Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1 | /* |
| 2 | * kernel/lockdep.c |
| 3 | * |
| 4 | * Runtime locking correctness validator |
| 5 | * |
| 6 | * Started by Ingo Molnar: |
| 7 | * |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
Peter Zijlstra | 90eec10 | 2015-11-16 11:08:45 +0100 | [diff] [blame] | 9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 10 | * |
| 11 | * this code maps all the lock dependencies as they occur in a live kernel |
| 12 | * and will warn about the following classes of locking bugs: |
| 13 | * |
| 14 | * - lock inversion scenarios |
| 15 | * - circular lock dependencies |
| 16 | * - hardirq/softirq safe/unsafe locking bugs |
| 17 | * |
| 18 | * Bugs are reported even if the current locking scenario does not cause |
| 19 | * any deadlock at this point. |
| 20 | * |
| 21 | * I.e. if anytime in the past two locks were taken in a different order, |
| 22 | * even if it happened for another task, even if those were different |
| 23 | * locks (but of the same class as this lock), this code will detect it. |
| 24 | * |
| 25 | * Thanks to Arjan van de Ven for coming up with the initial idea of |
| 26 | * mapping lock dependencies runtime. |
| 27 | */ |
Steven Rostedt | a5e2588 | 2008-12-02 15:34:05 -0500 | [diff] [blame] | 28 | #define DISABLE_BRANCH_PROFILING |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 29 | #include <linux/mutex.h> |
| 30 | #include <linux/sched.h> |
Ingo Molnar | e601757 | 2017-02-01 16:36:40 +0100 | [diff] [blame] | 31 | #include <linux/sched/clock.h> |
Ingo Molnar | 2993002 | 2017-02-08 18:51:36 +0100 | [diff] [blame] | 32 | #include <linux/sched/task.h> |
Nikolay Borisov | 6d7225f | 2017-05-03 14:53:05 -0700 | [diff] [blame] | 33 | #include <linux/sched/mm.h> |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 34 | #include <linux/delay.h> |
| 35 | #include <linux/module.h> |
| 36 | #include <linux/proc_fs.h> |
| 37 | #include <linux/seq_file.h> |
| 38 | #include <linux/spinlock.h> |
| 39 | #include <linux/kallsyms.h> |
| 40 | #include <linux/interrupt.h> |
| 41 | #include <linux/stacktrace.h> |
| 42 | #include <linux/debug_locks.h> |
| 43 | #include <linux/irqflags.h> |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 44 | #include <linux/utsname.h> |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 45 | #include <linux/hash.h> |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 46 | #include <linux/ftrace.h> |
Peter Zijlstra | b4b136f | 2009-01-29 14:50:36 +0100 | [diff] [blame] | 47 | #include <linux/stringify.h> |
Ming Lei | d588e46 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 48 | #include <linux/bitops.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 49 | #include <linux/gfp.h> |
Yong Zhang | d3d03d4 | 2011-11-09 16:04:51 +0800 | [diff] [blame] | 50 | #include <linux/kmemcheck.h> |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 51 | #include <linux/random.h> |
Peter Zijlstra | dfaaf3f | 2016-05-30 18:31:33 +0200 | [diff] [blame] | 52 | #include <linux/jhash.h> |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 53 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 54 | #include <asm/sections.h> |
| 55 | |
| 56 | #include "lockdep_internals.h" |
| 57 | |
Steven Rostedt | a8d154b | 2009-04-10 09:36:00 -0400 | [diff] [blame] | 58 | #define CREATE_TRACE_POINTS |
Frederic Weisbecker | 6717876 | 2009-11-13 10:06:34 +0100 | [diff] [blame] | 59 | #include <trace/events/lock.h> |
Steven Rostedt | a8d154b | 2009-04-10 09:36:00 -0400 | [diff] [blame] | 60 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 61 | #ifdef CONFIG_LOCKDEP_CROSSRELEASE |
| 62 | #include <linux/slab.h> |
| 63 | #endif |
| 64 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 65 | #ifdef CONFIG_PROVE_LOCKING |
| 66 | int prove_locking = 1; |
| 67 | module_param(prove_locking, int, 0644); |
| 68 | #else |
| 69 | #define prove_locking 0 |
| 70 | #endif |
| 71 | |
| 72 | #ifdef CONFIG_LOCK_STAT |
| 73 | int lock_stat = 1; |
| 74 | module_param(lock_stat, int, 0644); |
| 75 | #else |
| 76 | #define lock_stat 0 |
| 77 | #endif |
| 78 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 79 | /* |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 80 | * lockdep_lock: protects the lockdep graph, the hashes and the |
| 81 | * class/list/hash allocators. |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 82 | * |
| 83 | * This is one of the rare exceptions where it's justified |
| 84 | * to use a raw spinlock - we really dont want the spinlock |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 85 | * code to recurse back into the lockdep code... |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 86 | */ |
Thomas Gleixner | edc35bd | 2009-12-03 12:38:57 +0100 | [diff] [blame] | 87 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 88 | |
| 89 | static int graph_lock(void) |
| 90 | { |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 91 | arch_spin_lock(&lockdep_lock); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 92 | /* |
| 93 | * Make sure that if another CPU detected a bug while |
| 94 | * walking the graph we dont change it (while the other |
| 95 | * CPU is busy printing out stuff with the graph lock |
| 96 | * dropped already) |
| 97 | */ |
| 98 | if (!debug_locks) { |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 99 | arch_spin_unlock(&lockdep_lock); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 100 | return 0; |
| 101 | } |
Steven Rostedt | bb065af | 2008-05-12 21:21:00 +0200 | [diff] [blame] | 102 | /* prevent any recursions within lockdep from causing deadlocks */ |
| 103 | current->lockdep_recursion++; |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 104 | return 1; |
| 105 | } |
| 106 | |
| 107 | static inline int graph_unlock(void) |
| 108 | { |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 109 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) { |
| 110 | /* |
| 111 | * The lockdep graph lock isn't locked while we expect it to |
| 112 | * be, we're confused now, bye! |
| 113 | */ |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 114 | return DEBUG_LOCKS_WARN_ON(1); |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 115 | } |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 116 | |
Steven Rostedt | bb065af | 2008-05-12 21:21:00 +0200 | [diff] [blame] | 117 | current->lockdep_recursion--; |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 118 | arch_spin_unlock(&lockdep_lock); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 119 | return 0; |
| 120 | } |
| 121 | |
| 122 | /* |
| 123 | * Turn lock debugging off and return with 0 if it was off already, |
| 124 | * and also release the graph lock: |
| 125 | */ |
| 126 | static inline int debug_locks_off_graph_unlock(void) |
| 127 | { |
| 128 | int ret = debug_locks_off(); |
| 129 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 130 | arch_spin_unlock(&lockdep_lock); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 131 | |
| 132 | return ret; |
| 133 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 134 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 135 | unsigned long nr_list_entries; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 136 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 137 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 138 | /* |
| 139 | * All data structures here are protected by the global debug_lock. |
| 140 | * |
| 141 | * Mutex key structs only get allocated, once during bootup, and never |
| 142 | * get freed - this significantly simplifies the debugging code. |
| 143 | */ |
| 144 | unsigned long nr_lock_classes; |
| 145 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; |
| 146 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 147 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
| 148 | { |
| 149 | if (!hlock->class_idx) { |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 150 | /* |
| 151 | * Someone passed in garbage, we give up. |
| 152 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 153 | DEBUG_LOCKS_WARN_ON(1); |
| 154 | return NULL; |
| 155 | } |
| 156 | return lock_classes + hlock->class_idx - 1; |
| 157 | } |
| 158 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 159 | #ifdef CONFIG_LOCK_STAT |
Peter Zijlstra | 2552821 | 2016-03-15 14:52:49 -0700 | [diff] [blame] | 160 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], cpu_lock_stats); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 161 | |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 162 | static inline u64 lockstat_clock(void) |
| 163 | { |
Peter Zijlstra | c676329 | 2010-05-25 10:48:51 +0200 | [diff] [blame] | 164 | return local_clock(); |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 165 | } |
| 166 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 167 | static int lock_point(unsigned long points[], unsigned long ip) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 168 | { |
| 169 | int i; |
| 170 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 171 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
| 172 | if (points[i] == 0) { |
| 173 | points[i] = ip; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 174 | break; |
| 175 | } |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 176 | if (points[i] == ip) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 177 | break; |
| 178 | } |
| 179 | |
| 180 | return i; |
| 181 | } |
| 182 | |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 183 | static void lock_time_inc(struct lock_time *lt, u64 time) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 184 | { |
| 185 | if (time > lt->max) |
| 186 | lt->max = time; |
| 187 | |
Frank Rowand | 109d71c | 2009-11-19 13:42:06 -0800 | [diff] [blame] | 188 | if (time < lt->min || !lt->nr) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 189 | lt->min = time; |
| 190 | |
| 191 | lt->total += time; |
| 192 | lt->nr++; |
| 193 | } |
| 194 | |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 195 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
| 196 | { |
Frank Rowand | 109d71c | 2009-11-19 13:42:06 -0800 | [diff] [blame] | 197 | if (!src->nr) |
| 198 | return; |
| 199 | |
| 200 | if (src->max > dst->max) |
| 201 | dst->max = src->max; |
| 202 | |
| 203 | if (src->min < dst->min || !dst->nr) |
| 204 | dst->min = src->min; |
| 205 | |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 206 | dst->total += src->total; |
| 207 | dst->nr += src->nr; |
| 208 | } |
| 209 | |
| 210 | struct lock_class_stats lock_stats(struct lock_class *class) |
| 211 | { |
| 212 | struct lock_class_stats stats; |
| 213 | int cpu, i; |
| 214 | |
| 215 | memset(&stats, 0, sizeof(struct lock_class_stats)); |
| 216 | for_each_possible_cpu(cpu) { |
| 217 | struct lock_class_stats *pcs = |
Tejun Heo | 1871e52 | 2009-10-29 22:34:13 +0900 | [diff] [blame] | 218 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 219 | |
| 220 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) |
| 221 | stats.contention_point[i] += pcs->contention_point[i]; |
| 222 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 223 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
| 224 | stats.contending_point[i] += pcs->contending_point[i]; |
| 225 | |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 226 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
| 227 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); |
| 228 | |
| 229 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); |
| 230 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 231 | |
| 232 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) |
| 233 | stats.bounces[i] += pcs->bounces[i]; |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 234 | } |
| 235 | |
| 236 | return stats; |
| 237 | } |
| 238 | |
| 239 | void clear_lock_stats(struct lock_class *class) |
| 240 | { |
| 241 | int cpu; |
| 242 | |
| 243 | for_each_possible_cpu(cpu) { |
| 244 | struct lock_class_stats *cpu_stats = |
Tejun Heo | 1871e52 | 2009-10-29 22:34:13 +0900 | [diff] [blame] | 245 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 246 | |
| 247 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); |
| 248 | } |
| 249 | memset(class->contention_point, 0, sizeof(class->contention_point)); |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 250 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 251 | } |
| 252 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 253 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
| 254 | { |
Tejun Heo | 1871e52 | 2009-10-29 22:34:13 +0900 | [diff] [blame] | 255 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 256 | } |
| 257 | |
| 258 | static void put_lock_stats(struct lock_class_stats *stats) |
| 259 | { |
Tejun Heo | 1871e52 | 2009-10-29 22:34:13 +0900 | [diff] [blame] | 260 | put_cpu_var(cpu_lock_stats); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 261 | } |
| 262 | |
| 263 | static void lock_release_holdtime(struct held_lock *hlock) |
| 264 | { |
| 265 | struct lock_class_stats *stats; |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 266 | u64 holdtime; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 267 | |
| 268 | if (!lock_stat) |
| 269 | return; |
| 270 | |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 271 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 272 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 273 | stats = get_lock_stats(hlock_class(hlock)); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 274 | if (hlock->read) |
| 275 | lock_time_inc(&stats->read_holdtime, holdtime); |
| 276 | else |
| 277 | lock_time_inc(&stats->write_holdtime, holdtime); |
| 278 | put_lock_stats(stats); |
| 279 | } |
| 280 | #else |
| 281 | static inline void lock_release_holdtime(struct held_lock *hlock) |
| 282 | { |
| 283 | } |
| 284 | #endif |
| 285 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 286 | /* |
| 287 | * We keep a global list of all lock classes. The list only grows, |
| 288 | * never shrinks. The list is only accessed with the lockdep |
| 289 | * spinlock lock held. |
| 290 | */ |
| 291 | LIST_HEAD(all_lock_classes); |
| 292 | |
| 293 | /* |
| 294 | * The lockdep classes are in a hash-table as well, for fast lookup: |
| 295 | */ |
| 296 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) |
| 297 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 298 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 299 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
| 300 | |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 301 | static struct hlist_head classhash_table[CLASSHASH_SIZE]; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 302 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 303 | /* |
| 304 | * We put the lock dependency chains into a hash-table as well, to cache |
| 305 | * their existence: |
| 306 | */ |
| 307 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) |
| 308 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 309 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 310 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
| 311 | |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 312 | static struct hlist_head chainhash_table[CHAINHASH_SIZE]; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 313 | |
| 314 | /* |
| 315 | * The hash key of the lock dependency chains is a hash itself too: |
| 316 | * it's a hash of all locks taken up to that lock, including that lock. |
| 317 | * It's a 64-bit hash, because it's important for the keys to be |
| 318 | * unique. |
| 319 | */ |
Peter Zijlstra | dfaaf3f | 2016-05-30 18:31:33 +0200 | [diff] [blame] | 320 | static inline u64 iterate_chain_key(u64 key, u32 idx) |
| 321 | { |
| 322 | u32 k0 = key, k1 = key >> 32; |
| 323 | |
| 324 | __jhash_mix(idx, k0, k1); /* Macro that modifies arguments! */ |
| 325 | |
| 326 | return k0 | (u64)k1 << 32; |
| 327 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 328 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 329 | void lockdep_off(void) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 330 | { |
| 331 | current->lockdep_recursion++; |
| 332 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 333 | EXPORT_SYMBOL(lockdep_off); |
| 334 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 335 | void lockdep_on(void) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 336 | { |
| 337 | current->lockdep_recursion--; |
| 338 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 339 | EXPORT_SYMBOL(lockdep_on); |
| 340 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 341 | /* |
| 342 | * Debugging switches: |
| 343 | */ |
| 344 | |
| 345 | #define VERBOSE 0 |
Ingo Molnar | 33e94e9 | 2006-12-13 00:34:41 -0800 | [diff] [blame] | 346 | #define VERY_VERBOSE 0 |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 347 | |
| 348 | #if VERBOSE |
| 349 | # define HARDIRQ_VERBOSE 1 |
| 350 | # define SOFTIRQ_VERBOSE 1 |
| 351 | #else |
| 352 | # define HARDIRQ_VERBOSE 0 |
| 353 | # define SOFTIRQ_VERBOSE 0 |
| 354 | #endif |
| 355 | |
Peter Zijlstra | d92a8cf | 2017-03-03 10:13:38 +0100 | [diff] [blame] | 356 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 357 | /* |
| 358 | * Quick filtering for interesting events: |
| 359 | */ |
| 360 | static int class_filter(struct lock_class *class) |
| 361 | { |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 362 | #if 0 |
| 363 | /* Example */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 364 | if (class->name_version == 1 && |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 365 | !strcmp(class->name, "lockname")) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 366 | return 1; |
| 367 | if (class->name_version == 1 && |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 368 | !strcmp(class->name, "&struct->lockfield")) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 369 | return 1; |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 370 | #endif |
Ingo Molnar | a664089 | 2006-12-13 00:34:39 -0800 | [diff] [blame] | 371 | /* Filter everything else. 1 would be to allow everything else */ |
| 372 | return 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 373 | } |
| 374 | #endif |
| 375 | |
| 376 | static int verbose(struct lock_class *class) |
| 377 | { |
| 378 | #if VERBOSE |
| 379 | return class_filter(class); |
| 380 | #endif |
| 381 | return 0; |
| 382 | } |
| 383 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 384 | /* |
| 385 | * Stack-trace: tightly packed array of stack backtrace |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 386 | * addresses. Protected by the graph_lock. |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 387 | */ |
| 388 | unsigned long nr_stack_trace_entries; |
| 389 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; |
| 390 | |
Dave Jones | 2c52283 | 2013-04-25 13:40:02 -0400 | [diff] [blame] | 391 | static void print_lockdep_off(const char *bug_msg) |
| 392 | { |
| 393 | printk(KERN_DEBUG "%s\n", bug_msg); |
| 394 | printk(KERN_DEBUG "turning off the locking correctness validator.\n"); |
Andreas Gruenbacher | acf5937 | 2014-07-15 21:10:52 +0200 | [diff] [blame] | 395 | #ifdef CONFIG_LOCK_STAT |
Dave Jones | 2c52283 | 2013-04-25 13:40:02 -0400 | [diff] [blame] | 396 | printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n"); |
Andreas Gruenbacher | acf5937 | 2014-07-15 21:10:52 +0200 | [diff] [blame] | 397 | #endif |
Dave Jones | 2c52283 | 2013-04-25 13:40:02 -0400 | [diff] [blame] | 398 | } |
| 399 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 400 | static int save_trace(struct stack_trace *trace) |
| 401 | { |
| 402 | trace->nr_entries = 0; |
| 403 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; |
| 404 | trace->entries = stack_trace + nr_stack_trace_entries; |
| 405 | |
Andi Kleen | 5a1b399 | 2006-09-26 10:52:34 +0200 | [diff] [blame] | 406 | trace->skip = 3; |
Andi Kleen | 5a1b399 | 2006-09-26 10:52:34 +0200 | [diff] [blame] | 407 | |
Christoph Hellwig | ab1b6f0 | 2007-05-08 00:23:29 -0700 | [diff] [blame] | 408 | save_stack_trace(trace); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 409 | |
Peter Zijlstra | 4f84f43 | 2009-07-20 15:27:04 +0200 | [diff] [blame] | 410 | /* |
| 411 | * Some daft arches put -1 at the end to indicate its a full trace. |
| 412 | * |
| 413 | * <rant> this is buggy anyway, since it takes a whole extra entry so a |
| 414 | * complete trace that maxes out the entries provided will be reported |
| 415 | * as incomplete, friggin useless </rant> |
| 416 | */ |
Luck, Tony | ea5b41f | 2009-12-09 14:29:36 -0800 | [diff] [blame] | 417 | if (trace->nr_entries != 0 && |
| 418 | trace->entries[trace->nr_entries-1] == ULONG_MAX) |
Peter Zijlstra | 4f84f43 | 2009-07-20 15:27:04 +0200 | [diff] [blame] | 419 | trace->nr_entries--; |
| 420 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 421 | trace->max_entries = trace->nr_entries; |
| 422 | |
| 423 | nr_stack_trace_entries += trace->nr_entries; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 424 | |
Peter Zijlstra | 4f84f43 | 2009-07-20 15:27:04 +0200 | [diff] [blame] | 425 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 426 | if (!debug_locks_off_graph_unlock()) |
| 427 | return 0; |
| 428 | |
Dave Jones | 2c52283 | 2013-04-25 13:40:02 -0400 | [diff] [blame] | 429 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 430 | dump_stack(); |
| 431 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 432 | return 0; |
| 433 | } |
| 434 | |
| 435 | return 1; |
| 436 | } |
| 437 | |
| 438 | unsigned int nr_hardirq_chains; |
| 439 | unsigned int nr_softirq_chains; |
| 440 | unsigned int nr_process_chains; |
| 441 | unsigned int max_lockdep_depth; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 442 | |
| 443 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 444 | /* |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 445 | * Various lockdep statistics: |
| 446 | */ |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 447 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 448 | #endif |
| 449 | |
| 450 | /* |
| 451 | * Locking printouts: |
| 452 | */ |
| 453 | |
Peter Zijlstra | fabe9c4 | 2009-01-22 14:51:01 +0100 | [diff] [blame] | 454 | #define __USAGE(__STATE) \ |
Peter Zijlstra | b4b136f | 2009-01-29 14:50:36 +0100 | [diff] [blame] | 455 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
| 456 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ |
| 457 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ |
| 458 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", |
Peter Zijlstra | fabe9c4 | 2009-01-22 14:51:01 +0100 | [diff] [blame] | 459 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 460 | static const char *usage_str[] = |
| 461 | { |
Peter Zijlstra | fabe9c4 | 2009-01-22 14:51:01 +0100 | [diff] [blame] | 462 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
| 463 | #include "lockdep_states.h" |
| 464 | #undef LOCKDEP_STATE |
| 465 | [LOCK_USED] = "INITIAL USE", |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 466 | }; |
| 467 | |
| 468 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) |
| 469 | { |
Alexey Dobriyan | ffb4512 | 2007-05-08 00:28:41 -0700 | [diff] [blame] | 470 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 471 | } |
| 472 | |
Peter Zijlstra | 3ff176c | 2009-01-22 17:40:42 +0100 | [diff] [blame] | 473 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
| 474 | { |
| 475 | return 1UL << bit; |
| 476 | } |
| 477 | |
| 478 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
| 479 | { |
| 480 | char c = '.'; |
| 481 | |
| 482 | if (class->usage_mask & lock_flag(bit + 2)) |
| 483 | c = '+'; |
| 484 | if (class->usage_mask & lock_flag(bit)) { |
| 485 | c = '-'; |
| 486 | if (class->usage_mask & lock_flag(bit + 2)) |
| 487 | c = '?'; |
| 488 | } |
| 489 | |
| 490 | return c; |
| 491 | } |
| 492 | |
Peter Zijlstra | f510b23 | 2009-01-22 17:53:47 +0100 | [diff] [blame] | 493 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 494 | { |
Peter Zijlstra | f510b23 | 2009-01-22 17:53:47 +0100 | [diff] [blame] | 495 | int i = 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 496 | |
Peter Zijlstra | f510b23 | 2009-01-22 17:53:47 +0100 | [diff] [blame] | 497 | #define LOCKDEP_STATE(__STATE) \ |
| 498 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ |
| 499 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); |
| 500 | #include "lockdep_states.h" |
| 501 | #undef LOCKDEP_STATE |
| 502 | |
| 503 | usage[i] = '\0'; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 504 | } |
| 505 | |
Steven Rostedt | e5e78d0 | 2011-11-02 20:24:16 -0400 | [diff] [blame] | 506 | static void __print_lock_name(struct lock_class *class) |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 507 | { |
| 508 | char str[KSYM_NAME_LEN]; |
| 509 | const char *name; |
| 510 | |
| 511 | name = class->name; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 512 | if (!name) { |
| 513 | name = __get_key_name(class->key, str); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 514 | printk(KERN_CONT "%s", name); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 515 | } else { |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 516 | printk(KERN_CONT "%s", name); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 517 | if (class->name_version > 1) |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 518 | printk(KERN_CONT "#%d", class->name_version); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 519 | if (class->subclass) |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 520 | printk(KERN_CONT "/%d", class->subclass); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 521 | } |
Steven Rostedt | e5e78d0 | 2011-11-02 20:24:16 -0400 | [diff] [blame] | 522 | } |
| 523 | |
| 524 | static void print_lock_name(struct lock_class *class) |
| 525 | { |
| 526 | char usage[LOCK_USAGE_CHARS]; |
| 527 | |
| 528 | get_usage_chars(class, usage); |
| 529 | |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 530 | printk(KERN_CONT " ("); |
Steven Rostedt | e5e78d0 | 2011-11-02 20:24:16 -0400 | [diff] [blame] | 531 | __print_lock_name(class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 532 | printk(KERN_CONT "){%s}", usage); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 533 | } |
| 534 | |
| 535 | static void print_lockdep_cache(struct lockdep_map *lock) |
| 536 | { |
| 537 | const char *name; |
Tejun Heo | 9281ace | 2007-07-17 04:03:51 -0700 | [diff] [blame] | 538 | char str[KSYM_NAME_LEN]; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 539 | |
| 540 | name = lock->name; |
| 541 | if (!name) |
| 542 | name = __get_key_name(lock->key->subkeys, str); |
| 543 | |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 544 | printk(KERN_CONT "%s", name); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 545 | } |
| 546 | |
| 547 | static void print_lock(struct held_lock *hlock) |
| 548 | { |
Peter Zijlstra | d7bc319 | 2015-04-15 17:11:57 +0200 | [diff] [blame] | 549 | /* |
| 550 | * We can be called locklessly through debug_show_all_locks() so be |
| 551 | * extra careful, the hlock might have been released and cleared. |
| 552 | */ |
| 553 | unsigned int class_idx = hlock->class_idx; |
| 554 | |
| 555 | /* Don't re-read hlock->class_idx, can't use READ_ONCE() on bitfields: */ |
| 556 | barrier(); |
| 557 | |
| 558 | if (!class_idx || (class_idx - 1) >= MAX_LOCKDEP_KEYS) { |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 559 | printk(KERN_CONT "<RELEASED>\n"); |
Peter Zijlstra | d7bc319 | 2015-04-15 17:11:57 +0200 | [diff] [blame] | 560 | return; |
| 561 | } |
| 562 | |
| 563 | print_lock_name(lock_classes + class_idx - 1); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 564 | printk(KERN_CONT ", at: [<%p>] %pS\n", |
| 565 | (void *)hlock->acquire_ip, (void *)hlock->acquire_ip); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 566 | } |
| 567 | |
| 568 | static void lockdep_print_held_locks(struct task_struct *curr) |
| 569 | { |
| 570 | int i, depth = curr->lockdep_depth; |
| 571 | |
| 572 | if (!depth) { |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 573 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 574 | return; |
| 575 | } |
| 576 | printk("%d lock%s held by %s/%d:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 577 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 578 | |
| 579 | for (i = 0; i < depth; i++) { |
| 580 | printk(" #%d: ", i); |
| 581 | print_lock(curr->held_locks + i); |
| 582 | } |
| 583 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 584 | |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 585 | static void print_kernel_ident(void) |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 586 | { |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 587 | printk("%s %.*s %s\n", init_utsname()->release, |
Serge E. Hallyn | 96b644b | 2006-10-02 02:18:13 -0700 | [diff] [blame] | 588 | (int)strcspn(init_utsname()->version, " "), |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 589 | init_utsname()->version, |
| 590 | print_tainted()); |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 591 | } |
| 592 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 593 | static int very_verbose(struct lock_class *class) |
| 594 | { |
| 595 | #if VERY_VERBOSE |
| 596 | return class_filter(class); |
| 597 | #endif |
| 598 | return 0; |
| 599 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 600 | |
| 601 | /* |
| 602 | * Is this the address of a static object: |
| 603 | */ |
Sasha Levin | 8dce7a9 | 2013-06-13 18:41:16 -0400 | [diff] [blame] | 604 | #ifdef __KERNEL__ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 605 | static int static_obj(void *obj) |
| 606 | { |
| 607 | unsigned long start = (unsigned long) &_stext, |
| 608 | end = (unsigned long) &_end, |
| 609 | addr = (unsigned long) obj; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 610 | |
| 611 | /* |
| 612 | * static variable? |
| 613 | */ |
| 614 | if ((addr >= start) && (addr < end)) |
| 615 | return 1; |
| 616 | |
Mike Frysinger | 2a9ad18 | 2009-09-22 16:44:16 -0700 | [diff] [blame] | 617 | if (arch_is_kernel_data(addr)) |
| 618 | return 1; |
| 619 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 620 | /* |
Tejun Heo | 10fad5e | 2010-03-10 18:57:54 +0900 | [diff] [blame] | 621 | * in-kernel percpu var? |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 622 | */ |
Tejun Heo | 10fad5e | 2010-03-10 18:57:54 +0900 | [diff] [blame] | 623 | if (is_kernel_percpu_address(addr)) |
| 624 | return 1; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 625 | |
| 626 | /* |
Tejun Heo | 10fad5e | 2010-03-10 18:57:54 +0900 | [diff] [blame] | 627 | * module static or percpu var? |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 628 | */ |
Tejun Heo | 10fad5e | 2010-03-10 18:57:54 +0900 | [diff] [blame] | 629 | return is_module_address(addr) || is_module_percpu_address(addr); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 630 | } |
Sasha Levin | 8dce7a9 | 2013-06-13 18:41:16 -0400 | [diff] [blame] | 631 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 632 | |
| 633 | /* |
| 634 | * To make lock name printouts unique, we calculate a unique |
| 635 | * class->name_version generation counter: |
| 636 | */ |
| 637 | static int count_matching_names(struct lock_class *new_class) |
| 638 | { |
| 639 | struct lock_class *class; |
| 640 | int count = 0; |
| 641 | |
| 642 | if (!new_class->name) |
| 643 | return 0; |
| 644 | |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 645 | list_for_each_entry_rcu(class, &all_lock_classes, lock_entry) { |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 646 | if (new_class->key - new_class->subclass == class->key) |
| 647 | return class->name_version; |
| 648 | if (class->name && !strcmp(class->name, new_class->name)) |
| 649 | count = max(count, class->name_version); |
| 650 | } |
| 651 | |
| 652 | return count + 1; |
| 653 | } |
| 654 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 655 | /* |
| 656 | * Register a lock's class in the hash-table, if the class is not present |
| 657 | * yet. Otherwise we look it up. We cache the result in the lock object |
| 658 | * itself, so actual lookup of the hash should be once per lock object. |
| 659 | */ |
| 660 | static inline struct lock_class * |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 661 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 662 | { |
| 663 | struct lockdep_subclass_key *key; |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 664 | struct hlist_head *hash_head; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 665 | struct lock_class *class; |
Thomas Gleixner | 383776f | 2017-02-27 15:37:36 +0100 | [diff] [blame] | 666 | bool is_static = false; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 667 | |
Hitoshi Mitake | 4ba053c | 2010-10-13 17:30:26 +0900 | [diff] [blame] | 668 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
| 669 | debug_locks_off(); |
| 670 | printk(KERN_ERR |
| 671 | "BUG: looking up invalid subclass: %u\n", subclass); |
| 672 | printk(KERN_ERR |
| 673 | "turning off the locking correctness validator.\n"); |
| 674 | dump_stack(); |
| 675 | return NULL; |
| 676 | } |
| 677 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 678 | /* |
| 679 | * Static locks do not have their class-keys yet - for them the key |
Thomas Gleixner | 383776f | 2017-02-27 15:37:36 +0100 | [diff] [blame] | 680 | * is the lock object itself. If the lock is in the per cpu area, |
| 681 | * the canonical address of the lock (per cpu offset removed) is |
| 682 | * used. |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 683 | */ |
Thomas Gleixner | 383776f | 2017-02-27 15:37:36 +0100 | [diff] [blame] | 684 | if (unlikely(!lock->key)) { |
| 685 | unsigned long can_addr, addr = (unsigned long)lock; |
| 686 | |
| 687 | if (__is_kernel_percpu_address(addr, &can_addr)) |
| 688 | lock->key = (void *)can_addr; |
| 689 | else if (__is_module_percpu_address(addr, &can_addr)) |
| 690 | lock->key = (void *)can_addr; |
| 691 | else if (static_obj(lock)) |
| 692 | lock->key = (void *)lock; |
| 693 | else |
| 694 | return ERR_PTR(-EINVAL); |
| 695 | is_static = true; |
| 696 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 697 | |
| 698 | /* |
| 699 | * NOTE: the class-key must be unique. For dynamic locks, a static |
| 700 | * lock_class_key variable is passed in through the mutex_init() |
| 701 | * (or spin_lock_init()) call - which acts as the key. For static |
| 702 | * locks we use the lock object itself as the key. |
| 703 | */ |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 704 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
| 705 | sizeof(struct lockdep_map)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 706 | |
| 707 | key = lock->key->subkeys + subclass; |
| 708 | |
| 709 | hash_head = classhashentry(key); |
| 710 | |
| 711 | /* |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 712 | * We do an RCU walk of the hash, see lockdep_free_key_range(). |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 713 | */ |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 714 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 715 | return NULL; |
| 716 | |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 717 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 718 | if (class->key == key) { |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 719 | /* |
| 720 | * Huh! same key, different name? Did someone trample |
| 721 | * on some memory? We're most confused. |
| 722 | */ |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 723 | WARN_ON_ONCE(class->name != lock->name); |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 724 | return class; |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 725 | } |
| 726 | } |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 727 | |
Thomas Gleixner | 383776f | 2017-02-27 15:37:36 +0100 | [diff] [blame] | 728 | return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL); |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 729 | } |
| 730 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 731 | #ifdef CONFIG_LOCKDEP_CROSSRELEASE |
| 732 | static void cross_init(struct lockdep_map *lock, int cross); |
| 733 | static int cross_lock(struct lockdep_map *lock); |
| 734 | static int lock_acquire_crosslock(struct held_lock *hlock); |
| 735 | static int lock_release_crosslock(struct lockdep_map *lock); |
| 736 | #else |
| 737 | static inline void cross_init(struct lockdep_map *lock, int cross) {} |
| 738 | static inline int cross_lock(struct lockdep_map *lock) { return 0; } |
| 739 | static inline int lock_acquire_crosslock(struct held_lock *hlock) { return 2; } |
| 740 | static inline int lock_release_crosslock(struct lockdep_map *lock) { return 2; } |
| 741 | #endif |
| 742 | |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 743 | /* |
| 744 | * Register a lock's class in the hash-table, if the class is not present |
| 745 | * yet. Otherwise we look it up. We cache the result in the lock object |
| 746 | * itself, so actual lookup of the hash should be once per lock object. |
| 747 | */ |
Denys Vlasenko | c003ed9 | 2016-04-08 20:58:46 +0200 | [diff] [blame] | 748 | static struct lock_class * |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 749 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 750 | { |
| 751 | struct lockdep_subclass_key *key; |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 752 | struct hlist_head *hash_head; |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 753 | struct lock_class *class; |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 754 | |
| 755 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 756 | |
| 757 | class = look_up_lock_class(lock, subclass); |
Thomas Gleixner | 383776f | 2017-02-27 15:37:36 +0100 | [diff] [blame] | 758 | if (likely(!IS_ERR_OR_NULL(class))) |
Yong Zhang | 87cdee7 | 2011-11-09 16:07:14 +0800 | [diff] [blame] | 759 | goto out_set_class_cache; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 760 | |
| 761 | /* |
| 762 | * Debug-check: all keys must be persistent! |
Thomas Gleixner | 383776f | 2017-02-27 15:37:36 +0100 | [diff] [blame] | 763 | */ |
| 764 | if (IS_ERR(class)) { |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 765 | debug_locks_off(); |
| 766 | printk("INFO: trying to register non-static key.\n"); |
| 767 | printk("the code is fine but needs lockdep annotation.\n"); |
| 768 | printk("turning off the locking correctness validator.\n"); |
| 769 | dump_stack(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 770 | return NULL; |
| 771 | } |
| 772 | |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 773 | key = lock->key->subkeys + subclass; |
| 774 | hash_head = classhashentry(key); |
| 775 | |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 776 | if (!graph_lock()) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 777 | return NULL; |
| 778 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 779 | /* |
| 780 | * We have to do the hash-walk again, to avoid races |
| 781 | * with another CPU: |
| 782 | */ |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 783 | hlist_for_each_entry_rcu(class, hash_head, hash_entry) { |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 784 | if (class->key == key) |
| 785 | goto out_unlock_set; |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 786 | } |
| 787 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 788 | /* |
| 789 | * Allocate a new key from the static array, and add it to |
| 790 | * the hash: |
| 791 | */ |
| 792 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 793 | if (!debug_locks_off_graph_unlock()) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 794 | return NULL; |
| 795 | } |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 796 | |
Dave Jones | 2c52283 | 2013-04-25 13:40:02 -0400 | [diff] [blame] | 797 | print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!"); |
Peter Zijlstra | eedeeab | 2009-03-18 12:38:47 +0100 | [diff] [blame] | 798 | dump_stack(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 799 | return NULL; |
| 800 | } |
| 801 | class = lock_classes + nr_lock_classes++; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 802 | debug_atomic_inc(nr_unused_locks); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 803 | class->key = key; |
| 804 | class->name = lock->name; |
| 805 | class->subclass = subclass; |
| 806 | INIT_LIST_HEAD(&class->lock_entry); |
| 807 | INIT_LIST_HEAD(&class->locks_before); |
| 808 | INIT_LIST_HEAD(&class->locks_after); |
| 809 | class->name_version = count_matching_names(class); |
| 810 | /* |
| 811 | * We use RCU's safe list-add method to make |
| 812 | * parallel walking of the hash-list safe: |
| 813 | */ |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 814 | hlist_add_head_rcu(&class->hash_entry, hash_head); |
Dale Farnsworth | 1481197 | 2008-02-25 23:03:02 +0100 | [diff] [blame] | 815 | /* |
| 816 | * Add it to the global list of classes: |
| 817 | */ |
| 818 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 819 | |
| 820 | if (verbose(class)) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 821 | graph_unlock(); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 822 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 823 | printk("\nnew class %p: %s", class->key, class->name); |
| 824 | if (class->name_version > 1) |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 825 | printk(KERN_CONT "#%d", class->name_version); |
| 826 | printk(KERN_CONT "\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 827 | dump_stack(); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 828 | |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 829 | if (!graph_lock()) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 830 | return NULL; |
| 831 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 832 | } |
| 833 | out_unlock_set: |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 834 | graph_unlock(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 835 | |
Yong Zhang | 87cdee7 | 2011-11-09 16:07:14 +0800 | [diff] [blame] | 836 | out_set_class_cache: |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 837 | if (!subclass || force) |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 838 | lock->class_cache[0] = class; |
| 839 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
| 840 | lock->class_cache[subclass] = class; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 841 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 842 | /* |
| 843 | * Hash collision, did we smoke some? We found a class with a matching |
| 844 | * hash but the subclass -- which is hashed in -- didn't match. |
| 845 | */ |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 846 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
| 847 | return NULL; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 848 | |
| 849 | return class; |
| 850 | } |
| 851 | |
Peter Zijlstra | ca58abc | 2007-07-19 01:48:53 -0700 | [diff] [blame] | 852 | #ifdef CONFIG_PROVE_LOCKING |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 853 | /* |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 854 | * Allocate a lockdep entry. (assumes the graph_lock held, returns |
| 855 | * with NULL on failure) |
| 856 | */ |
| 857 | static struct lock_list *alloc_list_entry(void) |
| 858 | { |
| 859 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { |
| 860 | if (!debug_locks_off_graph_unlock()) |
| 861 | return NULL; |
| 862 | |
Dave Jones | 2c52283 | 2013-04-25 13:40:02 -0400 | [diff] [blame] | 863 | print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!"); |
Peter Zijlstra | eedeeab | 2009-03-18 12:38:47 +0100 | [diff] [blame] | 864 | dump_stack(); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 865 | return NULL; |
| 866 | } |
| 867 | return list_entries + nr_list_entries++; |
| 868 | } |
| 869 | |
| 870 | /* |
| 871 | * Add a new dependency to the head of the list: |
| 872 | */ |
Tahsin Erdogan | 83f0616 | 2016-11-08 00:02:07 -0800 | [diff] [blame] | 873 | static int add_lock_to_list(struct lock_class *this, struct list_head *head, |
| 874 | unsigned long ip, int distance, |
| 875 | struct stack_trace *trace) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 876 | { |
| 877 | struct lock_list *entry; |
| 878 | /* |
| 879 | * Lock not present yet - get a new dependency struct and |
| 880 | * add it to the list: |
| 881 | */ |
| 882 | entry = alloc_list_entry(); |
| 883 | if (!entry) |
| 884 | return 0; |
| 885 | |
Zhu Yi | 7487017 | 2008-08-27 14:33:00 +0800 | [diff] [blame] | 886 | entry->class = this; |
| 887 | entry->distance = distance; |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 888 | entry->trace = *trace; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 889 | /* |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 890 | * Both allocation and removal are done under the graph lock; but |
| 891 | * iteration is under RCU-sched; see look_up_lock_class() and |
| 892 | * lockdep_free_key_range(). |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 893 | */ |
| 894 | list_add_tail_rcu(&entry->entry, head); |
| 895 | |
| 896 | return 1; |
| 897 | } |
| 898 | |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 899 | /* |
| 900 | * For good efficiency of modular, we use power of 2 |
| 901 | */ |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 902 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
| 903 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) |
| 904 | |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 905 | /* |
| 906 | * The circular_queue and helpers is used to implement the |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 907 | * breadth-first search(BFS)algorithem, by which we can build |
| 908 | * the shortest path from the next lock to be acquired to the |
| 909 | * previous held lock if there is a circular between them. |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 910 | */ |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 911 | struct circular_queue { |
| 912 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; |
| 913 | unsigned int front, rear; |
| 914 | }; |
| 915 | |
| 916 | static struct circular_queue lock_cq; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 917 | |
Ming Lei | 12f3dfd | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 918 | unsigned int max_bfs_queue_depth; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 919 | |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 920 | static unsigned int lockdep_dependency_gen_id; |
| 921 | |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 922 | static inline void __cq_init(struct circular_queue *cq) |
| 923 | { |
| 924 | cq->front = cq->rear = 0; |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 925 | lockdep_dependency_gen_id++; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 926 | } |
| 927 | |
| 928 | static inline int __cq_empty(struct circular_queue *cq) |
| 929 | { |
| 930 | return (cq->front == cq->rear); |
| 931 | } |
| 932 | |
| 933 | static inline int __cq_full(struct circular_queue *cq) |
| 934 | { |
| 935 | return ((cq->rear + 1) & CQ_MASK) == cq->front; |
| 936 | } |
| 937 | |
| 938 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) |
| 939 | { |
| 940 | if (__cq_full(cq)) |
| 941 | return -1; |
| 942 | |
| 943 | cq->element[cq->rear] = elem; |
| 944 | cq->rear = (cq->rear + 1) & CQ_MASK; |
| 945 | return 0; |
| 946 | } |
| 947 | |
| 948 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) |
| 949 | { |
| 950 | if (__cq_empty(cq)) |
| 951 | return -1; |
| 952 | |
| 953 | *elem = cq->element[cq->front]; |
| 954 | cq->front = (cq->front + 1) & CQ_MASK; |
| 955 | return 0; |
| 956 | } |
| 957 | |
| 958 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) |
| 959 | { |
| 960 | return (cq->rear - cq->front) & CQ_MASK; |
| 961 | } |
| 962 | |
| 963 | static inline void mark_lock_accessed(struct lock_list *lock, |
| 964 | struct lock_list *parent) |
| 965 | { |
| 966 | unsigned long nr; |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 967 | |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 968 | nr = lock - list_entries; |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 969 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 970 | lock->parent = parent; |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 971 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 972 | } |
| 973 | |
| 974 | static inline unsigned long lock_accessed(struct lock_list *lock) |
| 975 | { |
| 976 | unsigned long nr; |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 977 | |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 978 | nr = lock - list_entries; |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 979 | WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */ |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 980 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 981 | } |
| 982 | |
| 983 | static inline struct lock_list *get_lock_parent(struct lock_list *child) |
| 984 | { |
| 985 | return child->parent; |
| 986 | } |
| 987 | |
| 988 | static inline int get_lock_depth(struct lock_list *child) |
| 989 | { |
| 990 | int depth = 0; |
| 991 | struct lock_list *parent; |
| 992 | |
| 993 | while ((parent = get_lock_parent(child))) { |
| 994 | child = parent; |
| 995 | depth++; |
| 996 | } |
| 997 | return depth; |
| 998 | } |
| 999 | |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1000 | static int __bfs(struct lock_list *source_entry, |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1001 | void *data, |
| 1002 | int (*match)(struct lock_list *entry, void *data), |
| 1003 | struct lock_list **target_entry, |
| 1004 | int forward) |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1005 | { |
| 1006 | struct lock_list *entry; |
Ming Lei | d588e46 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1007 | struct list_head *head; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1008 | struct circular_queue *cq = &lock_cq; |
| 1009 | int ret = 1; |
| 1010 | |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1011 | if (match(source_entry, data)) { |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1012 | *target_entry = source_entry; |
| 1013 | ret = 0; |
| 1014 | goto exit; |
| 1015 | } |
| 1016 | |
Ming Lei | d588e46 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1017 | if (forward) |
| 1018 | head = &source_entry->class->locks_after; |
| 1019 | else |
| 1020 | head = &source_entry->class->locks_before; |
| 1021 | |
| 1022 | if (list_empty(head)) |
| 1023 | goto exit; |
| 1024 | |
| 1025 | __cq_init(cq); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1026 | __cq_enqueue(cq, (unsigned long)source_entry); |
| 1027 | |
| 1028 | while (!__cq_empty(cq)) { |
| 1029 | struct lock_list *lock; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1030 | |
| 1031 | __cq_dequeue(cq, (unsigned long *)&lock); |
| 1032 | |
| 1033 | if (!lock->class) { |
| 1034 | ret = -2; |
| 1035 | goto exit; |
| 1036 | } |
| 1037 | |
| 1038 | if (forward) |
| 1039 | head = &lock->class->locks_after; |
| 1040 | else |
| 1041 | head = &lock->class->locks_before; |
| 1042 | |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 1043 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
| 1044 | |
| 1045 | list_for_each_entry_rcu(entry, head, entry) { |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1046 | if (!lock_accessed(entry)) { |
Ming Lei | 12f3dfd | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1047 | unsigned int cq_depth; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1048 | mark_lock_accessed(entry, lock); |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1049 | if (match(entry, data)) { |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1050 | *target_entry = entry; |
| 1051 | ret = 0; |
| 1052 | goto exit; |
| 1053 | } |
| 1054 | |
| 1055 | if (__cq_enqueue(cq, (unsigned long)entry)) { |
| 1056 | ret = -1; |
| 1057 | goto exit; |
| 1058 | } |
Ming Lei | 12f3dfd | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1059 | cq_depth = __cq_get_elem_count(cq); |
| 1060 | if (max_bfs_queue_depth < cq_depth) |
| 1061 | max_bfs_queue_depth = cq_depth; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1062 | } |
| 1063 | } |
| 1064 | } |
| 1065 | exit: |
| 1066 | return ret; |
| 1067 | } |
| 1068 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1069 | static inline int __bfs_forwards(struct lock_list *src_entry, |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1070 | void *data, |
| 1071 | int (*match)(struct lock_list *entry, void *data), |
| 1072 | struct lock_list **target_entry) |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1073 | { |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1074 | return __bfs(src_entry, data, match, target_entry, 1); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1075 | |
| 1076 | } |
| 1077 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1078 | static inline int __bfs_backwards(struct lock_list *src_entry, |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1079 | void *data, |
| 1080 | int (*match)(struct lock_list *entry, void *data), |
| 1081 | struct lock_list **target_entry) |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1082 | { |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1083 | return __bfs(src_entry, data, match, target_entry, 0); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1084 | |
| 1085 | } |
| 1086 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1087 | /* |
| 1088 | * Recursive, forwards-direction lock-dependency checking, used for |
| 1089 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe |
| 1090 | * checking. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1091 | */ |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1092 | |
| 1093 | /* |
| 1094 | * Print a dependency chain entry (this is only done when a deadlock |
| 1095 | * has been detected): |
| 1096 | */ |
| 1097 | static noinline int |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1098 | print_circular_bug_entry(struct lock_list *target, int depth) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1099 | { |
| 1100 | if (debug_locks_silent) |
| 1101 | return 0; |
| 1102 | printk("\n-> #%u", depth); |
| 1103 | print_lock_name(target->class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1104 | printk(KERN_CONT ":\n"); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1105 | print_stack_trace(&target->trace, 6); |
| 1106 | |
| 1107 | return 0; |
| 1108 | } |
| 1109 | |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1110 | static void |
| 1111 | print_circular_lock_scenario(struct held_lock *src, |
| 1112 | struct held_lock *tgt, |
| 1113 | struct lock_list *prt) |
| 1114 | { |
| 1115 | struct lock_class *source = hlock_class(src); |
| 1116 | struct lock_class *target = hlock_class(tgt); |
| 1117 | struct lock_class *parent = prt->class; |
| 1118 | |
| 1119 | /* |
| 1120 | * A direct locking problem where unsafe_class lock is taken |
| 1121 | * directly by safe_class lock, then all we need to show |
| 1122 | * is the deadlock scenario, as it is obvious that the |
| 1123 | * unsafe lock is taken under the safe lock. |
| 1124 | * |
| 1125 | * But if there is a chain instead, where the safe lock takes |
| 1126 | * an intermediate lock (middle_class) where this lock is |
| 1127 | * not the same as the safe lock, then the lock chain is |
| 1128 | * used to describe the problem. Otherwise we would need |
| 1129 | * to show a different CPU case for each link in the chain |
| 1130 | * from the safe_class lock to the unsafe_class lock. |
| 1131 | */ |
| 1132 | if (parent != source) { |
| 1133 | printk("Chain exists of:\n "); |
| 1134 | __print_lock_name(source); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1135 | printk(KERN_CONT " --> "); |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1136 | __print_lock_name(parent); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1137 | printk(KERN_CONT " --> "); |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1138 | __print_lock_name(target); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1139 | printk(KERN_CONT "\n\n"); |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1140 | } |
| 1141 | |
Byungchul Park | 383a4bc | 2017-08-07 16:12:55 +0900 | [diff] [blame] | 1142 | if (cross_lock(tgt->instance)) { |
| 1143 | printk(" Possible unsafe locking scenario by crosslock:\n\n"); |
| 1144 | printk(" CPU0 CPU1\n"); |
| 1145 | printk(" ---- ----\n"); |
| 1146 | printk(" lock("); |
| 1147 | __print_lock_name(parent); |
| 1148 | printk(KERN_CONT ");\n"); |
| 1149 | printk(" lock("); |
| 1150 | __print_lock_name(target); |
| 1151 | printk(KERN_CONT ");\n"); |
| 1152 | printk(" lock("); |
| 1153 | __print_lock_name(source); |
| 1154 | printk(KERN_CONT ");\n"); |
| 1155 | printk(" unlock("); |
| 1156 | __print_lock_name(target); |
| 1157 | printk(KERN_CONT ");\n"); |
| 1158 | printk("\n *** DEADLOCK ***\n\n"); |
| 1159 | } else { |
| 1160 | printk(" Possible unsafe locking scenario:\n\n"); |
| 1161 | printk(" CPU0 CPU1\n"); |
| 1162 | printk(" ---- ----\n"); |
| 1163 | printk(" lock("); |
| 1164 | __print_lock_name(target); |
| 1165 | printk(KERN_CONT ");\n"); |
| 1166 | printk(" lock("); |
| 1167 | __print_lock_name(parent); |
| 1168 | printk(KERN_CONT ");\n"); |
| 1169 | printk(" lock("); |
| 1170 | __print_lock_name(target); |
| 1171 | printk(KERN_CONT ");\n"); |
| 1172 | printk(" lock("); |
| 1173 | __print_lock_name(source); |
| 1174 | printk(KERN_CONT ");\n"); |
| 1175 | printk("\n *** DEADLOCK ***\n\n"); |
| 1176 | } |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1177 | } |
| 1178 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1179 | /* |
| 1180 | * When a circular dependency is detected, print the |
| 1181 | * header first: |
| 1182 | */ |
| 1183 | static noinline int |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1184 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
| 1185 | struct held_lock *check_src, |
| 1186 | struct held_lock *check_tgt) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1187 | { |
| 1188 | struct task_struct *curr = current; |
| 1189 | |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1190 | if (debug_locks_silent) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1191 | return 0; |
| 1192 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1193 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 1194 | pr_warn("======================================================\n"); |
| 1195 | pr_warn("WARNING: possible circular locking dependency detected\n"); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 1196 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 1197 | pr_warn("------------------------------------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1198 | pr_warn("%s/%d is trying to acquire lock:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 1199 | curr->comm, task_pid_nr(curr)); |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1200 | print_lock(check_src); |
Byungchul Park | 383a4bc | 2017-08-07 16:12:55 +0900 | [diff] [blame] | 1201 | |
| 1202 | if (cross_lock(check_tgt->instance)) |
| 1203 | pr_warn("\nbut now in release context of a crosslock acquired at the following:\n"); |
| 1204 | else |
| 1205 | pr_warn("\nbut task is already holding lock:\n"); |
| 1206 | |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1207 | print_lock(check_tgt); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1208 | pr_warn("\nwhich lock already depends on the new lock.\n\n"); |
| 1209 | pr_warn("\nthe existing dependency chain (in reverse order) is:\n"); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1210 | |
| 1211 | print_circular_bug_entry(entry, depth); |
| 1212 | |
| 1213 | return 0; |
| 1214 | } |
| 1215 | |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1216 | static inline int class_equal(struct lock_list *entry, void *data) |
| 1217 | { |
| 1218 | return entry->class == data; |
| 1219 | } |
| 1220 | |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1221 | static noinline int print_circular_bug(struct lock_list *this, |
| 1222 | struct lock_list *target, |
| 1223 | struct held_lock *check_src, |
Byungchul Park | 383a4bc | 2017-08-07 16:12:55 +0900 | [diff] [blame] | 1224 | struct held_lock *check_tgt, |
| 1225 | struct stack_trace *trace) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1226 | { |
| 1227 | struct task_struct *curr = current; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1228 | struct lock_list *parent; |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1229 | struct lock_list *first_parent; |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1230 | int depth; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1231 | |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1232 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1233 | return 0; |
| 1234 | |
Byungchul Park | 383a4bc | 2017-08-07 16:12:55 +0900 | [diff] [blame] | 1235 | if (cross_lock(check_tgt->instance)) |
| 1236 | this->trace = *trace; |
| 1237 | else if (!save_trace(&this->trace)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1238 | return 0; |
| 1239 | |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1240 | depth = get_lock_depth(target); |
| 1241 | |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1242 | print_circular_bug_header(target, depth, check_src, check_tgt); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1243 | |
| 1244 | parent = get_lock_parent(target); |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1245 | first_parent = parent; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1246 | |
| 1247 | while (parent) { |
| 1248 | print_circular_bug_entry(parent, --depth); |
| 1249 | parent = get_lock_parent(parent); |
| 1250 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1251 | |
| 1252 | printk("\nother info that might help us debug this:\n\n"); |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1253 | print_circular_lock_scenario(check_src, check_tgt, |
| 1254 | first_parent); |
| 1255 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1256 | lockdep_print_held_locks(curr); |
| 1257 | |
| 1258 | printk("\nstack backtrace:\n"); |
| 1259 | dump_stack(); |
| 1260 | |
| 1261 | return 0; |
| 1262 | } |
| 1263 | |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1264 | static noinline int print_bfs_bug(int ret) |
| 1265 | { |
| 1266 | if (!debug_locks_off_graph_unlock()) |
| 1267 | return 0; |
| 1268 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 1269 | /* |
| 1270 | * Breadth-first-search failed, graph got corrupted? |
| 1271 | */ |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1272 | WARN(1, "lockdep bfs error:%d\n", ret); |
| 1273 | |
| 1274 | return 0; |
| 1275 | } |
| 1276 | |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1277 | static int noop_count(struct lock_list *entry, void *data) |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1278 | { |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1279 | (*(unsigned long *)data)++; |
| 1280 | return 0; |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1281 | } |
| 1282 | |
Fengguang Wu | 5216d53 | 2013-11-09 00:55:35 +0800 | [diff] [blame] | 1283 | static unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1284 | { |
| 1285 | unsigned long count = 0; |
| 1286 | struct lock_list *uninitialized_var(target_entry); |
| 1287 | |
| 1288 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
| 1289 | |
| 1290 | return count; |
| 1291 | } |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1292 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
| 1293 | { |
| 1294 | unsigned long ret, flags; |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1295 | struct lock_list this; |
| 1296 | |
| 1297 | this.parent = NULL; |
| 1298 | this.class = class; |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1299 | |
| 1300 | local_irq_save(flags); |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 1301 | arch_spin_lock(&lockdep_lock); |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1302 | ret = __lockdep_count_forward_deps(&this); |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 1303 | arch_spin_unlock(&lockdep_lock); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1304 | local_irq_restore(flags); |
| 1305 | |
| 1306 | return ret; |
| 1307 | } |
| 1308 | |
Fengguang Wu | 5216d53 | 2013-11-09 00:55:35 +0800 | [diff] [blame] | 1309 | static unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1310 | { |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1311 | unsigned long count = 0; |
| 1312 | struct lock_list *uninitialized_var(target_entry); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1313 | |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1314 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1315 | |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1316 | return count; |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1317 | } |
| 1318 | |
| 1319 | unsigned long lockdep_count_backward_deps(struct lock_class *class) |
| 1320 | { |
| 1321 | unsigned long ret, flags; |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1322 | struct lock_list this; |
| 1323 | |
| 1324 | this.parent = NULL; |
| 1325 | this.class = class; |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1326 | |
| 1327 | local_irq_save(flags); |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 1328 | arch_spin_lock(&lockdep_lock); |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1329 | ret = __lockdep_count_backward_deps(&this); |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 1330 | arch_spin_unlock(&lockdep_lock); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1331 | local_irq_restore(flags); |
| 1332 | |
| 1333 | return ret; |
| 1334 | } |
| 1335 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1336 | /* |
| 1337 | * Prove that the dependency graph starting at <entry> can not |
| 1338 | * lead to <target>. Print an error and return 0 if it does. |
| 1339 | */ |
| 1340 | static noinline int |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1341 | check_noncircular(struct lock_list *root, struct lock_class *target, |
| 1342 | struct lock_list **target_entry) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1343 | { |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1344 | int result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1345 | |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 1346 | debug_atomic_inc(nr_cyclic_checks); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1347 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1348 | result = __bfs_forwards(root, target, class_equal, target_entry); |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1349 | |
| 1350 | return result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1351 | } |
| 1352 | |
Peter Zijlstra | ae81330 | 2017-03-03 10:13:38 +0100 | [diff] [blame] | 1353 | static noinline int |
| 1354 | check_redundant(struct lock_list *root, struct lock_class *target, |
| 1355 | struct lock_list **target_entry) |
| 1356 | { |
| 1357 | int result; |
| 1358 | |
| 1359 | debug_atomic_inc(nr_redundant_checks); |
| 1360 | |
| 1361 | result = __bfs_forwards(root, target, class_equal, target_entry); |
| 1362 | |
| 1363 | return result; |
| 1364 | } |
| 1365 | |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 1366 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1367 | /* |
| 1368 | * Forwards and backwards subgraph searching, for the purposes of |
| 1369 | * proving that two subgraphs can be connected by a new dependency |
| 1370 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. |
| 1371 | */ |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1372 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1373 | static inline int usage_match(struct lock_list *entry, void *bit) |
| 1374 | { |
| 1375 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); |
| 1376 | } |
| 1377 | |
| 1378 | |
| 1379 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1380 | /* |
| 1381 | * Find a node in the forwards-direction dependency sub-graph starting |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1382 | * at @root->class that matches @bit. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1383 | * |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1384 | * Return 0 if such a node exists in the subgraph, and put that node |
| 1385 | * into *@target_entry. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1386 | * |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1387 | * Return 1 otherwise and keep *@target_entry unchanged. |
| 1388 | * Return <0 on error. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1389 | */ |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1390 | static int |
| 1391 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, |
| 1392 | struct lock_list **target_entry) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1393 | { |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1394 | int result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1395 | |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 1396 | debug_atomic_inc(nr_find_usage_forwards_checks); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1397 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1398 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
| 1399 | |
| 1400 | return result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1401 | } |
| 1402 | |
| 1403 | /* |
| 1404 | * Find a node in the backwards-direction dependency sub-graph starting |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1405 | * at @root->class that matches @bit. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1406 | * |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1407 | * Return 0 if such a node exists in the subgraph, and put that node |
| 1408 | * into *@target_entry. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1409 | * |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1410 | * Return 1 otherwise and keep *@target_entry unchanged. |
| 1411 | * Return <0 on error. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1412 | */ |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1413 | static int |
| 1414 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, |
| 1415 | struct lock_list **target_entry) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1416 | { |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1417 | int result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1418 | |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 1419 | debug_atomic_inc(nr_find_usage_backwards_checks); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1420 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1421 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1422 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1423 | return result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1424 | } |
| 1425 | |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1426 | static void print_lock_class_header(struct lock_class *class, int depth) |
| 1427 | { |
| 1428 | int bit; |
| 1429 | |
| 1430 | printk("%*s->", depth, ""); |
| 1431 | print_lock_name(class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1432 | printk(KERN_CONT " ops: %lu", class->ops); |
| 1433 | printk(KERN_CONT " {\n"); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1434 | |
| 1435 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { |
| 1436 | if (class->usage_mask & (1 << bit)) { |
| 1437 | int len = depth; |
| 1438 | |
| 1439 | len += printk("%*s %s", depth, "", usage_str[bit]); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1440 | len += printk(KERN_CONT " at:\n"); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1441 | print_stack_trace(class->usage_traces + bit, len); |
| 1442 | } |
| 1443 | } |
| 1444 | printk("%*s }\n", depth, ""); |
| 1445 | |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1446 | printk("%*s ... key at: [<%p>] %pS\n", |
| 1447 | depth, "", class->key, class->key); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1448 | } |
| 1449 | |
| 1450 | /* |
| 1451 | * printk the shortest lock dependencies from @start to @end in reverse order: |
| 1452 | */ |
| 1453 | static void __used |
| 1454 | print_shortest_lock_dependencies(struct lock_list *leaf, |
| 1455 | struct lock_list *root) |
| 1456 | { |
| 1457 | struct lock_list *entry = leaf; |
| 1458 | int depth; |
| 1459 | |
| 1460 | /*compute depth from generated tree by BFS*/ |
| 1461 | depth = get_lock_depth(leaf); |
| 1462 | |
| 1463 | do { |
| 1464 | print_lock_class_header(entry->class, depth); |
| 1465 | printk("%*s ... acquired at:\n", depth, ""); |
| 1466 | print_stack_trace(&entry->trace, 2); |
| 1467 | printk("\n"); |
| 1468 | |
| 1469 | if (depth == 0 && (entry != root)) { |
Steven Rostedt | 6be8c39 | 2011-04-20 21:41:58 -0400 | [diff] [blame] | 1470 | printk("lockdep:%s bad path found in chain graph\n", __func__); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1471 | break; |
| 1472 | } |
| 1473 | |
| 1474 | entry = get_lock_parent(entry); |
| 1475 | depth--; |
| 1476 | } while (entry && (depth >= 0)); |
| 1477 | |
| 1478 | return; |
| 1479 | } |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1480 | |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1481 | static void |
| 1482 | print_irq_lock_scenario(struct lock_list *safe_entry, |
| 1483 | struct lock_list *unsafe_entry, |
Steven Rostedt | dad3d74 | 2011-04-20 21:41:57 -0400 | [diff] [blame] | 1484 | struct lock_class *prev_class, |
| 1485 | struct lock_class *next_class) |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1486 | { |
| 1487 | struct lock_class *safe_class = safe_entry->class; |
| 1488 | struct lock_class *unsafe_class = unsafe_entry->class; |
Steven Rostedt | dad3d74 | 2011-04-20 21:41:57 -0400 | [diff] [blame] | 1489 | struct lock_class *middle_class = prev_class; |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1490 | |
| 1491 | if (middle_class == safe_class) |
Steven Rostedt | dad3d74 | 2011-04-20 21:41:57 -0400 | [diff] [blame] | 1492 | middle_class = next_class; |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1493 | |
| 1494 | /* |
| 1495 | * A direct locking problem where unsafe_class lock is taken |
| 1496 | * directly by safe_class lock, then all we need to show |
| 1497 | * is the deadlock scenario, as it is obvious that the |
| 1498 | * unsafe lock is taken under the safe lock. |
| 1499 | * |
| 1500 | * But if there is a chain instead, where the safe lock takes |
| 1501 | * an intermediate lock (middle_class) where this lock is |
| 1502 | * not the same as the safe lock, then the lock chain is |
| 1503 | * used to describe the problem. Otherwise we would need |
| 1504 | * to show a different CPU case for each link in the chain |
| 1505 | * from the safe_class lock to the unsafe_class lock. |
| 1506 | */ |
| 1507 | if (middle_class != unsafe_class) { |
| 1508 | printk("Chain exists of:\n "); |
| 1509 | __print_lock_name(safe_class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1510 | printk(KERN_CONT " --> "); |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1511 | __print_lock_name(middle_class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1512 | printk(KERN_CONT " --> "); |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1513 | __print_lock_name(unsafe_class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1514 | printk(KERN_CONT "\n\n"); |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1515 | } |
| 1516 | |
| 1517 | printk(" Possible interrupt unsafe locking scenario:\n\n"); |
| 1518 | printk(" CPU0 CPU1\n"); |
| 1519 | printk(" ---- ----\n"); |
| 1520 | printk(" lock("); |
| 1521 | __print_lock_name(unsafe_class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1522 | printk(KERN_CONT ");\n"); |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1523 | printk(" local_irq_disable();\n"); |
| 1524 | printk(" lock("); |
| 1525 | __print_lock_name(safe_class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1526 | printk(KERN_CONT ");\n"); |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1527 | printk(" lock("); |
| 1528 | __print_lock_name(middle_class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1529 | printk(KERN_CONT ");\n"); |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1530 | printk(" <Interrupt>\n"); |
| 1531 | printk(" lock("); |
| 1532 | __print_lock_name(safe_class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1533 | printk(KERN_CONT ");\n"); |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1534 | printk("\n *** DEADLOCK ***\n\n"); |
| 1535 | } |
| 1536 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1537 | static int |
| 1538 | print_bad_irq_dependency(struct task_struct *curr, |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1539 | struct lock_list *prev_root, |
| 1540 | struct lock_list *next_root, |
| 1541 | struct lock_list *backwards_entry, |
| 1542 | struct lock_list *forwards_entry, |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1543 | struct held_lock *prev, |
| 1544 | struct held_lock *next, |
| 1545 | enum lock_usage_bit bit1, |
| 1546 | enum lock_usage_bit bit2, |
| 1547 | const char *irqclass) |
| 1548 | { |
| 1549 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
| 1550 | return 0; |
| 1551 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1552 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 1553 | pr_warn("=====================================================\n"); |
| 1554 | pr_warn("WARNING: %s-safe -> %s-unsafe lock order detected\n", |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1555 | irqclass, irqclass); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 1556 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 1557 | pr_warn("-----------------------------------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1558 | pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 1559 | curr->comm, task_pid_nr(curr), |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1560 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
| 1561 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, |
| 1562 | curr->hardirqs_enabled, |
| 1563 | curr->softirqs_enabled); |
| 1564 | print_lock(next); |
| 1565 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1566 | pr_warn("\nand this task is already holding:\n"); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1567 | print_lock(prev); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1568 | pr_warn("which would create a new lock dependency:\n"); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1569 | print_lock_name(hlock_class(prev)); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1570 | pr_cont(" ->"); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1571 | print_lock_name(hlock_class(next)); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1572 | pr_cont("\n"); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1573 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1574 | pr_warn("\nbut this new dependency connects a %s-irq-safe lock:\n", |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1575 | irqclass); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1576 | print_lock_name(backwards_entry->class); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1577 | pr_warn("\n... which became %s-irq-safe at:\n", irqclass); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1578 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1579 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1580 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1581 | pr_warn("\nto a %s-irq-unsafe lock:\n", irqclass); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1582 | print_lock_name(forwards_entry->class); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1583 | pr_warn("\n... which became %s-irq-unsafe at:\n", irqclass); |
| 1584 | pr_warn("..."); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1585 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1586 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1587 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1588 | pr_warn("\nother info that might help us debug this:\n\n"); |
Steven Rostedt | dad3d74 | 2011-04-20 21:41:57 -0400 | [diff] [blame] | 1589 | print_irq_lock_scenario(backwards_entry, forwards_entry, |
| 1590 | hlock_class(prev), hlock_class(next)); |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1591 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1592 | lockdep_print_held_locks(curr); |
| 1593 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1594 | pr_warn("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1595 | if (!save_trace(&prev_root->trace)) |
| 1596 | return 0; |
| 1597 | print_shortest_lock_dependencies(backwards_entry, prev_root); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1598 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1599 | pr_warn("\nthe dependencies between the lock to be acquired"); |
| 1600 | pr_warn(" and %s-irq-unsafe lock:\n", irqclass); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1601 | if (!save_trace(&next_root->trace)) |
| 1602 | return 0; |
| 1603 | print_shortest_lock_dependencies(forwards_entry, next_root); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1604 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1605 | pr_warn("\nstack backtrace:\n"); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1606 | dump_stack(); |
| 1607 | |
| 1608 | return 0; |
| 1609 | } |
| 1610 | |
| 1611 | static int |
| 1612 | check_usage(struct task_struct *curr, struct held_lock *prev, |
| 1613 | struct held_lock *next, enum lock_usage_bit bit_backwards, |
| 1614 | enum lock_usage_bit bit_forwards, const char *irqclass) |
| 1615 | { |
| 1616 | int ret; |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1617 | struct lock_list this, that; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1618 | struct lock_list *uninitialized_var(target_entry); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1619 | struct lock_list *uninitialized_var(target_entry1); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1620 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1621 | this.parent = NULL; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1622 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1623 | this.class = hlock_class(prev); |
| 1624 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1625 | if (ret < 0) |
| 1626 | return print_bfs_bug(ret); |
| 1627 | if (ret == 1) |
| 1628 | return ret; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1629 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1630 | that.parent = NULL; |
| 1631 | that.class = hlock_class(next); |
| 1632 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1633 | if (ret < 0) |
| 1634 | return print_bfs_bug(ret); |
| 1635 | if (ret == 1) |
| 1636 | return ret; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1637 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1638 | return print_bad_irq_dependency(curr, &this, &that, |
| 1639 | target_entry, target_entry1, |
| 1640 | prev, next, |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1641 | bit_backwards, bit_forwards, irqclass); |
| 1642 | } |
| 1643 | |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1644 | static const char *state_names[] = { |
| 1645 | #define LOCKDEP_STATE(__STATE) \ |
Peter Zijlstra | b4b136f | 2009-01-29 14:50:36 +0100 | [diff] [blame] | 1646 | __stringify(__STATE), |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1647 | #include "lockdep_states.h" |
| 1648 | #undef LOCKDEP_STATE |
| 1649 | }; |
| 1650 | |
| 1651 | static const char *state_rnames[] = { |
| 1652 | #define LOCKDEP_STATE(__STATE) \ |
Peter Zijlstra | b4b136f | 2009-01-29 14:50:36 +0100 | [diff] [blame] | 1653 | __stringify(__STATE)"-READ", |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1654 | #include "lockdep_states.h" |
| 1655 | #undef LOCKDEP_STATE |
| 1656 | }; |
| 1657 | |
| 1658 | static inline const char *state_name(enum lock_usage_bit bit) |
| 1659 | { |
| 1660 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
| 1661 | } |
| 1662 | |
| 1663 | static int exclusive_bit(int new_bit) |
| 1664 | { |
| 1665 | /* |
| 1666 | * USED_IN |
| 1667 | * USED_IN_READ |
| 1668 | * ENABLED |
| 1669 | * ENABLED_READ |
| 1670 | * |
| 1671 | * bit 0 - write/read |
| 1672 | * bit 1 - used_in/enabled |
| 1673 | * bit 2+ state |
| 1674 | */ |
| 1675 | |
| 1676 | int state = new_bit & ~3; |
| 1677 | int dir = new_bit & 2; |
| 1678 | |
| 1679 | /* |
| 1680 | * keep state, bit flip the direction and strip read. |
| 1681 | */ |
| 1682 | return state | (dir ^ 2); |
| 1683 | } |
| 1684 | |
| 1685 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, |
| 1686 | struct held_lock *next, enum lock_usage_bit bit) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1687 | { |
| 1688 | /* |
| 1689 | * Prove that the new dependency does not connect a hardirq-safe |
| 1690 | * lock with a hardirq-unsafe lock - to achieve this we search |
| 1691 | * the backwards-subgraph starting at <prev>, and the |
| 1692 | * forwards-subgraph starting at <next>: |
| 1693 | */ |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1694 | if (!check_usage(curr, prev, next, bit, |
| 1695 | exclusive_bit(bit), state_name(bit))) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1696 | return 0; |
| 1697 | |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1698 | bit++; /* _READ */ |
| 1699 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1700 | /* |
| 1701 | * Prove that the new dependency does not connect a hardirq-safe-read |
| 1702 | * lock with a hardirq-unsafe lock - to achieve this we search |
| 1703 | * the backwards-subgraph starting at <prev>, and the |
| 1704 | * forwards-subgraph starting at <next>: |
| 1705 | */ |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1706 | if (!check_usage(curr, prev, next, bit, |
| 1707 | exclusive_bit(bit), state_name(bit))) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1708 | return 0; |
| 1709 | |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1710 | return 1; |
| 1711 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1712 | |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1713 | static int |
| 1714 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, |
| 1715 | struct held_lock *next) |
| 1716 | { |
| 1717 | #define LOCKDEP_STATE(__STATE) \ |
| 1718 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 1719 | return 0; |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1720 | #include "lockdep_states.h" |
| 1721 | #undef LOCKDEP_STATE |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 1722 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1723 | return 1; |
| 1724 | } |
| 1725 | |
| 1726 | static void inc_chains(void) |
| 1727 | { |
| 1728 | if (current->hardirq_context) |
| 1729 | nr_hardirq_chains++; |
| 1730 | else { |
| 1731 | if (current->softirq_context) |
| 1732 | nr_softirq_chains++; |
| 1733 | else |
| 1734 | nr_process_chains++; |
| 1735 | } |
| 1736 | } |
| 1737 | |
| 1738 | #else |
| 1739 | |
| 1740 | static inline int |
| 1741 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, |
| 1742 | struct held_lock *next) |
| 1743 | { |
| 1744 | return 1; |
| 1745 | } |
| 1746 | |
| 1747 | static inline void inc_chains(void) |
| 1748 | { |
| 1749 | nr_process_chains++; |
| 1750 | } |
| 1751 | |
| 1752 | #endif |
| 1753 | |
Steven Rostedt | 48702ec | 2011-04-20 21:41:56 -0400 | [diff] [blame] | 1754 | static void |
| 1755 | print_deadlock_scenario(struct held_lock *nxt, |
| 1756 | struct held_lock *prv) |
| 1757 | { |
| 1758 | struct lock_class *next = hlock_class(nxt); |
| 1759 | struct lock_class *prev = hlock_class(prv); |
| 1760 | |
| 1761 | printk(" Possible unsafe locking scenario:\n\n"); |
| 1762 | printk(" CPU0\n"); |
| 1763 | printk(" ----\n"); |
| 1764 | printk(" lock("); |
| 1765 | __print_lock_name(prev); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1766 | printk(KERN_CONT ");\n"); |
Steven Rostedt | 48702ec | 2011-04-20 21:41:56 -0400 | [diff] [blame] | 1767 | printk(" lock("); |
| 1768 | __print_lock_name(next); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 1769 | printk(KERN_CONT ");\n"); |
Steven Rostedt | 48702ec | 2011-04-20 21:41:56 -0400 | [diff] [blame] | 1770 | printk("\n *** DEADLOCK ***\n\n"); |
| 1771 | printk(" May be due to missing lock nesting notation\n\n"); |
| 1772 | } |
| 1773 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1774 | static int |
| 1775 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, |
| 1776 | struct held_lock *next) |
| 1777 | { |
| 1778 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
| 1779 | return 0; |
| 1780 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1781 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 1782 | pr_warn("============================================\n"); |
| 1783 | pr_warn("WARNING: possible recursive locking detected\n"); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 1784 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 1785 | pr_warn("--------------------------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1786 | pr_warn("%s/%d is trying to acquire lock:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 1787 | curr->comm, task_pid_nr(curr)); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1788 | print_lock(next); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1789 | pr_warn("\nbut task is already holding lock:\n"); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1790 | print_lock(prev); |
| 1791 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1792 | pr_warn("\nother info that might help us debug this:\n"); |
Steven Rostedt | 48702ec | 2011-04-20 21:41:56 -0400 | [diff] [blame] | 1793 | print_deadlock_scenario(next, prev); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1794 | lockdep_print_held_locks(curr); |
| 1795 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 1796 | pr_warn("\nstack backtrace:\n"); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1797 | dump_stack(); |
| 1798 | |
| 1799 | return 0; |
| 1800 | } |
| 1801 | |
| 1802 | /* |
| 1803 | * Check whether we are holding such a class already. |
| 1804 | * |
| 1805 | * (Note that this has to be done separately, because the graph cannot |
| 1806 | * detect such classes of deadlocks.) |
| 1807 | * |
| 1808 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read |
| 1809 | */ |
| 1810 | static int |
| 1811 | check_deadlock(struct task_struct *curr, struct held_lock *next, |
| 1812 | struct lockdep_map *next_instance, int read) |
| 1813 | { |
| 1814 | struct held_lock *prev; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 1815 | struct held_lock *nest = NULL; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1816 | int i; |
| 1817 | |
| 1818 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 1819 | prev = curr->held_locks + i; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 1820 | |
| 1821 | if (prev->instance == next->nest_lock) |
| 1822 | nest = prev; |
| 1823 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1824 | if (hlock_class(prev) != hlock_class(next)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1825 | continue; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 1826 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1827 | /* |
| 1828 | * Allow read-after-read recursion of the same |
| 1829 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
| 1830 | */ |
| 1831 | if ((read == 2) && prev->read) |
| 1832 | return 2; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 1833 | |
| 1834 | /* |
| 1835 | * We're holding the nest_lock, which serializes this lock's |
| 1836 | * nesting behaviour. |
| 1837 | */ |
| 1838 | if (nest) |
| 1839 | return 2; |
| 1840 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 1841 | if (cross_lock(prev->instance)) |
| 1842 | continue; |
| 1843 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1844 | return print_deadlock_bug(curr, prev, next); |
| 1845 | } |
| 1846 | return 1; |
| 1847 | } |
| 1848 | |
| 1849 | /* |
| 1850 | * There was a chain-cache miss, and we are about to add a new dependency |
| 1851 | * to a previous lock. We recursively validate the following rules: |
| 1852 | * |
| 1853 | * - would the adding of the <prev> -> <next> dependency create a |
| 1854 | * circular dependency in the graph? [== circular deadlock] |
| 1855 | * |
| 1856 | * - does the new prev->next dependency connect any hardirq-safe lock |
| 1857 | * (in the full backwards-subgraph starting at <prev>) with any |
| 1858 | * hardirq-unsafe lock (in the full forwards-subgraph starting at |
| 1859 | * <next>)? [== illegal lock inversion with hardirq contexts] |
| 1860 | * |
| 1861 | * - does the new prev->next dependency connect any softirq-safe lock |
| 1862 | * (in the full backwards-subgraph starting at <prev>) with any |
| 1863 | * softirq-unsafe lock (in the full forwards-subgraph starting at |
| 1864 | * <next>)? [== illegal lock inversion with softirq contexts] |
| 1865 | * |
| 1866 | * any of these scenarios could lead to a deadlock. |
| 1867 | * |
| 1868 | * Then if all the validations pass, we add the forwards and backwards |
| 1869 | * dependency. |
| 1870 | */ |
| 1871 | static int |
| 1872 | check_prev_add(struct task_struct *curr, struct held_lock *prev, |
Byungchul Park | ce07a941 | 2017-08-07 16:12:51 +0900 | [diff] [blame] | 1873 | struct held_lock *next, int distance, struct stack_trace *trace, |
| 1874 | int (*save)(struct stack_trace *trace)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1875 | { |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1876 | struct lock_list *uninitialized_var(target_entry); |
Peter Zijlstra | 8b405d5 | 2017-10-04 11:13:37 +0200 | [diff] [blame] | 1877 | struct lock_list *entry; |
| 1878 | struct lock_list this; |
| 1879 | int ret; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1880 | |
| 1881 | /* |
| 1882 | * Prove that the new <prev> -> <next> dependency would not |
| 1883 | * create a circular dependency in the graph. (We do this by |
| 1884 | * forward-recursing into the graph starting at <next>, and |
| 1885 | * checking whether we can reach <prev>.) |
| 1886 | * |
| 1887 | * We are using global variables to control the recursion, to |
| 1888 | * keep the stackframe size of the recursive functions low: |
| 1889 | */ |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1890 | this.class = hlock_class(next); |
| 1891 | this.parent = NULL; |
| 1892 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); |
Peter Zijlstra | 8b405d5 | 2017-10-04 11:13:37 +0200 | [diff] [blame] | 1893 | if (unlikely(!ret)) { |
| 1894 | if (!trace->entries) { |
| 1895 | /* |
| 1896 | * If @save fails here, the printing might trigger |
| 1897 | * a WARN but because of the !nr_entries it should |
| 1898 | * not do bad things. |
| 1899 | */ |
| 1900 | save(trace); |
| 1901 | } |
Byungchul Park | 383a4bc | 2017-08-07 16:12:55 +0900 | [diff] [blame] | 1902 | return print_circular_bug(&this, target_entry, next, prev, trace); |
Peter Zijlstra | 8b405d5 | 2017-10-04 11:13:37 +0200 | [diff] [blame] | 1903 | } |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1904 | else if (unlikely(ret < 0)) |
| 1905 | return print_bfs_bug(ret); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1906 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1907 | if (!check_prev_add_irq(curr, prev, next)) |
| 1908 | return 0; |
| 1909 | |
| 1910 | /* |
| 1911 | * For recursive read-locks we do all the dependency checks, |
| 1912 | * but we dont store read-triggered dependencies (only |
| 1913 | * write-triggered dependencies). This ensures that only the |
| 1914 | * write-side dependencies matter, and that if for example a |
| 1915 | * write-lock never takes any other locks, then the reads are |
| 1916 | * equivalent to a NOP. |
| 1917 | */ |
| 1918 | if (next->read == 2 || prev->read == 2) |
| 1919 | return 1; |
| 1920 | /* |
| 1921 | * Is the <prev> -> <next> dependency already present? |
| 1922 | * |
| 1923 | * (this may occur even though this is a new chain: consider |
| 1924 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 |
| 1925 | * chains - the second one will be new, but L1 already has |
| 1926 | * L2 added to its dependency list, due to the first chain.) |
| 1927 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1928 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
| 1929 | if (entry->class == hlock_class(next)) { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1930 | if (distance == 1) |
| 1931 | entry->distance = 1; |
Byungchul Park | 70911fd | 2017-08-07 16:12:50 +0900 | [diff] [blame] | 1932 | return 1; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1933 | } |
| 1934 | } |
| 1935 | |
Peter Zijlstra | ae81330 | 2017-03-03 10:13:38 +0100 | [diff] [blame] | 1936 | /* |
| 1937 | * Is the <prev> -> <next> link redundant? |
| 1938 | */ |
| 1939 | this.class = hlock_class(prev); |
| 1940 | this.parent = NULL; |
| 1941 | ret = check_redundant(&this, hlock_class(next), &target_entry); |
| 1942 | if (!ret) { |
| 1943 | debug_atomic_inc(nr_redundant); |
| 1944 | return 2; |
| 1945 | } |
| 1946 | if (ret < 0) |
| 1947 | return print_bfs_bug(ret); |
| 1948 | |
| 1949 | |
Peter Zijlstra | 8b405d5 | 2017-10-04 11:13:37 +0200 | [diff] [blame] | 1950 | if (!trace->entries && !save(trace)) |
Byungchul Park | ce07a941 | 2017-08-07 16:12:51 +0900 | [diff] [blame] | 1951 | return 0; |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 1952 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1953 | /* |
| 1954 | * Ok, all validations passed, add the new lock |
| 1955 | * to the previous lock's dependency list: |
| 1956 | */ |
Tahsin Erdogan | 83f0616 | 2016-11-08 00:02:07 -0800 | [diff] [blame] | 1957 | ret = add_lock_to_list(hlock_class(next), |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1958 | &hlock_class(prev)->locks_after, |
Byungchul Park | ce07a941 | 2017-08-07 16:12:51 +0900 | [diff] [blame] | 1959 | next->acquire_ip, distance, trace); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1960 | |
| 1961 | if (!ret) |
| 1962 | return 0; |
| 1963 | |
Tahsin Erdogan | 83f0616 | 2016-11-08 00:02:07 -0800 | [diff] [blame] | 1964 | ret = add_lock_to_list(hlock_class(prev), |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1965 | &hlock_class(next)->locks_before, |
Byungchul Park | ce07a941 | 2017-08-07 16:12:51 +0900 | [diff] [blame] | 1966 | next->acquire_ip, distance, trace); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1967 | if (!ret) |
| 1968 | return 0; |
| 1969 | |
Byungchul Park | 70911fd | 2017-08-07 16:12:50 +0900 | [diff] [blame] | 1970 | return 2; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1971 | } |
| 1972 | |
| 1973 | /* |
| 1974 | * Add the dependency to all directly-previous locks that are 'relevant'. |
| 1975 | * The ones that are relevant are (in increasing distance from curr): |
| 1976 | * all consecutive trylock entries and the final non-trylock entry - or |
| 1977 | * the end of this context's lock-chain - whichever comes first. |
| 1978 | */ |
| 1979 | static int |
| 1980 | check_prevs_add(struct task_struct *curr, struct held_lock *next) |
| 1981 | { |
| 1982 | int depth = curr->lockdep_depth; |
| 1983 | struct held_lock *hlock; |
Peter Zijlstra | 8b405d5 | 2017-10-04 11:13:37 +0200 | [diff] [blame] | 1984 | struct stack_trace trace = { |
| 1985 | .nr_entries = 0, |
| 1986 | .max_entries = 0, |
| 1987 | .entries = NULL, |
| 1988 | .skip = 0, |
| 1989 | }; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1990 | |
| 1991 | /* |
| 1992 | * Debugging checks. |
| 1993 | * |
| 1994 | * Depth must not be zero for a non-head lock: |
| 1995 | */ |
| 1996 | if (!depth) |
| 1997 | goto out_bug; |
| 1998 | /* |
| 1999 | * At least two relevant locks must exist for this |
| 2000 | * to be a head: |
| 2001 | */ |
| 2002 | if (curr->held_locks[depth].irq_context != |
| 2003 | curr->held_locks[depth-1].irq_context) |
| 2004 | goto out_bug; |
| 2005 | |
| 2006 | for (;;) { |
| 2007 | int distance = curr->lockdep_depth - depth + 1; |
Oleg Nesterov | 1b5ff81 | 2014-01-20 19:20:10 +0100 | [diff] [blame] | 2008 | hlock = curr->held_locks + depth - 1; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2009 | /* |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 2010 | * Only non-crosslock entries get new dependencies added. |
| 2011 | * Crosslock entries will be added by commit later: |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2012 | */ |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 2013 | if (!cross_lock(hlock->instance)) { |
Byungchul Park | ce07a941 | 2017-08-07 16:12:51 +0900 | [diff] [blame] | 2014 | /* |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 2015 | * Only non-recursive-read entries get new dependencies |
| 2016 | * added: |
Byungchul Park | ce07a941 | 2017-08-07 16:12:51 +0900 | [diff] [blame] | 2017 | */ |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 2018 | if (hlock->read != 2 && hlock->check) { |
| 2019 | int ret = check_prev_add(curr, hlock, next, |
Peter Zijlstra | 8b405d5 | 2017-10-04 11:13:37 +0200 | [diff] [blame] | 2020 | distance, &trace, save_trace); |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 2021 | if (!ret) |
| 2022 | return 0; |
Byungchul Park | ce07a941 | 2017-08-07 16:12:51 +0900 | [diff] [blame] | 2023 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 2024 | /* |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 2025 | * Stop after the first non-trylock entry, |
| 2026 | * as non-trylock entries have added their |
| 2027 | * own direct dependencies already, so this |
| 2028 | * lock is connected to them indirectly: |
| 2029 | */ |
| 2030 | if (!hlock->trylock) |
| 2031 | break; |
| 2032 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2033 | } |
| 2034 | depth--; |
| 2035 | /* |
| 2036 | * End of lock-stack? |
| 2037 | */ |
| 2038 | if (!depth) |
| 2039 | break; |
| 2040 | /* |
| 2041 | * Stop the search if we cross into another context: |
| 2042 | */ |
| 2043 | if (curr->held_locks[depth].irq_context != |
| 2044 | curr->held_locks[depth-1].irq_context) |
| 2045 | break; |
| 2046 | } |
| 2047 | return 1; |
| 2048 | out_bug: |
| 2049 | if (!debug_locks_off_graph_unlock()) |
| 2050 | return 0; |
| 2051 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2052 | /* |
| 2053 | * Clearly we all shouldn't be here, but since we made it we |
| 2054 | * can reliable say we messed up our state. See the above two |
| 2055 | * gotos for reasons why we could possibly end up here. |
| 2056 | */ |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2057 | WARN_ON(1); |
| 2058 | |
| 2059 | return 0; |
| 2060 | } |
| 2061 | |
| 2062 | unsigned long nr_lock_chains; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2063 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
Huang, Ying | cd1a28e | 2008-06-23 11:20:54 +0800 | [diff] [blame] | 2064 | int nr_chain_hlocks; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2065 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
| 2066 | |
| 2067 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) |
| 2068 | { |
| 2069 | return lock_classes + chain_hlocks[chain->base + i]; |
| 2070 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2071 | |
| 2072 | /* |
Ingo Molnar | 9e4e755 | 2016-02-29 10:03:58 +0100 | [diff] [blame] | 2073 | * Returns the index of the first held_lock of the current chain |
| 2074 | */ |
| 2075 | static inline int get_first_held_lock(struct task_struct *curr, |
| 2076 | struct held_lock *hlock) |
| 2077 | { |
| 2078 | int i; |
| 2079 | struct held_lock *hlock_curr; |
| 2080 | |
| 2081 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { |
| 2082 | hlock_curr = curr->held_locks + i; |
| 2083 | if (hlock_curr->irq_context != hlock->irq_context) |
| 2084 | break; |
| 2085 | |
| 2086 | } |
| 2087 | |
| 2088 | return ++i; |
| 2089 | } |
| 2090 | |
Borislav Petkov | 5c8a010 | 2016-04-04 10:42:07 +0200 | [diff] [blame] | 2091 | #ifdef CONFIG_DEBUG_LOCKDEP |
Ingo Molnar | 9e4e755 | 2016-02-29 10:03:58 +0100 | [diff] [blame] | 2092 | /* |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2093 | * Returns the next chain_key iteration |
| 2094 | */ |
| 2095 | static u64 print_chain_key_iteration(int class_idx, u64 chain_key) |
| 2096 | { |
| 2097 | u64 new_chain_key = iterate_chain_key(chain_key, class_idx); |
| 2098 | |
| 2099 | printk(" class_idx:%d -> chain_key:%016Lx", |
| 2100 | class_idx, |
| 2101 | (unsigned long long)new_chain_key); |
| 2102 | return new_chain_key; |
| 2103 | } |
| 2104 | |
| 2105 | static void |
| 2106 | print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) |
| 2107 | { |
| 2108 | struct held_lock *hlock; |
| 2109 | u64 chain_key = 0; |
| 2110 | int depth = curr->lockdep_depth; |
| 2111 | int i; |
| 2112 | |
| 2113 | printk("depth: %u\n", depth + 1); |
| 2114 | for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) { |
| 2115 | hlock = curr->held_locks + i; |
| 2116 | chain_key = print_chain_key_iteration(hlock->class_idx, chain_key); |
| 2117 | |
| 2118 | print_lock(hlock); |
| 2119 | } |
| 2120 | |
| 2121 | print_chain_key_iteration(hlock_next->class_idx, chain_key); |
| 2122 | print_lock(hlock_next); |
| 2123 | } |
| 2124 | |
| 2125 | static void print_chain_keys_chain(struct lock_chain *chain) |
| 2126 | { |
| 2127 | int i; |
| 2128 | u64 chain_key = 0; |
| 2129 | int class_id; |
| 2130 | |
| 2131 | printk("depth: %u\n", chain->depth); |
| 2132 | for (i = 0; i < chain->depth; i++) { |
| 2133 | class_id = chain_hlocks[chain->base + i]; |
| 2134 | chain_key = print_chain_key_iteration(class_id + 1, chain_key); |
| 2135 | |
| 2136 | print_lock_name(lock_classes + class_id); |
| 2137 | printk("\n"); |
| 2138 | } |
| 2139 | } |
| 2140 | |
| 2141 | static void print_collision(struct task_struct *curr, |
| 2142 | struct held_lock *hlock_next, |
| 2143 | struct lock_chain *chain) |
| 2144 | { |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2145 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 2146 | pr_warn("============================\n"); |
| 2147 | pr_warn("WARNING: chain_key collision\n"); |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2148 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 2149 | pr_warn("----------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2150 | pr_warn("%s/%d: ", current->comm, task_pid_nr(current)); |
| 2151 | pr_warn("Hash chain already cached but the contents don't match!\n"); |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2152 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2153 | pr_warn("Held locks:"); |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2154 | print_chain_keys_held_locks(curr, hlock_next); |
| 2155 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2156 | pr_warn("Locks in cached chain:"); |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2157 | print_chain_keys_chain(chain); |
| 2158 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2159 | pr_warn("\nstack backtrace:\n"); |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2160 | dump_stack(); |
| 2161 | } |
Borislav Petkov | 5c8a010 | 2016-04-04 10:42:07 +0200 | [diff] [blame] | 2162 | #endif |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2163 | |
| 2164 | /* |
Ingo Molnar | 9e4e755 | 2016-02-29 10:03:58 +0100 | [diff] [blame] | 2165 | * Checks whether the chain and the current held locks are consistent |
| 2166 | * in depth and also in content. If they are not it most likely means |
| 2167 | * that there was a collision during the calculation of the chain_key. |
| 2168 | * Returns: 0 not passed, 1 passed |
| 2169 | */ |
| 2170 | static int check_no_collision(struct task_struct *curr, |
| 2171 | struct held_lock *hlock, |
| 2172 | struct lock_chain *chain) |
| 2173 | { |
| 2174 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 2175 | int i, j, id; |
| 2176 | |
| 2177 | i = get_first_held_lock(curr, hlock); |
| 2178 | |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2179 | if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) { |
| 2180 | print_collision(curr, hlock, chain); |
Ingo Molnar | 9e4e755 | 2016-02-29 10:03:58 +0100 | [diff] [blame] | 2181 | return 0; |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2182 | } |
Ingo Molnar | 9e4e755 | 2016-02-29 10:03:58 +0100 | [diff] [blame] | 2183 | |
| 2184 | for (j = 0; j < chain->depth - 1; j++, i++) { |
| 2185 | id = curr->held_locks[i].class_idx - 1; |
| 2186 | |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2187 | if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) { |
| 2188 | print_collision(curr, hlock, chain); |
Ingo Molnar | 9e4e755 | 2016-02-29 10:03:58 +0100 | [diff] [blame] | 2189 | return 0; |
Alfredo Alvarez Fernandez | 39e2e17 | 2016-03-30 19:03:36 +0200 | [diff] [blame] | 2190 | } |
Ingo Molnar | 9e4e755 | 2016-02-29 10:03:58 +0100 | [diff] [blame] | 2191 | } |
| 2192 | #endif |
| 2193 | return 1; |
| 2194 | } |
| 2195 | |
| 2196 | /* |
Byungchul Park | 49347a9 | 2017-08-07 16:12:49 +0900 | [diff] [blame] | 2197 | * This is for building a chain between just two different classes, |
| 2198 | * instead of adding a new hlock upon current, which is done by |
| 2199 | * add_chain_cache(). |
| 2200 | * |
| 2201 | * This can be called in any context with two classes, while |
| 2202 | * add_chain_cache() must be done within the lock owener's context |
| 2203 | * since it uses hlock which might be racy in another context. |
| 2204 | */ |
| 2205 | static inline int add_chain_cache_classes(unsigned int prev, |
| 2206 | unsigned int next, |
| 2207 | unsigned int irq_context, |
| 2208 | u64 chain_key) |
| 2209 | { |
| 2210 | struct hlist_head *hash_head = chainhashentry(chain_key); |
| 2211 | struct lock_chain *chain; |
| 2212 | |
| 2213 | /* |
| 2214 | * Allocate a new chain entry from the static array, and add |
| 2215 | * it to the hash: |
| 2216 | */ |
| 2217 | |
| 2218 | /* |
| 2219 | * We might need to take the graph lock, ensure we've got IRQs |
| 2220 | * disabled to make this an IRQ-safe lock.. for recursion reasons |
| 2221 | * lockdep won't complain about its own locking errors. |
| 2222 | */ |
| 2223 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2224 | return 0; |
| 2225 | |
| 2226 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { |
| 2227 | if (!debug_locks_off_graph_unlock()) |
| 2228 | return 0; |
| 2229 | |
| 2230 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
| 2231 | dump_stack(); |
| 2232 | return 0; |
| 2233 | } |
| 2234 | |
| 2235 | chain = lock_chains + nr_lock_chains++; |
| 2236 | chain->chain_key = chain_key; |
| 2237 | chain->irq_context = irq_context; |
| 2238 | chain->depth = 2; |
| 2239 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
| 2240 | chain->base = nr_chain_hlocks; |
| 2241 | nr_chain_hlocks += chain->depth; |
| 2242 | chain_hlocks[chain->base] = prev - 1; |
| 2243 | chain_hlocks[chain->base + 1] = next -1; |
| 2244 | } |
| 2245 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 2246 | /* |
| 2247 | * Important for check_no_collision(). |
| 2248 | */ |
| 2249 | else { |
| 2250 | if (!debug_locks_off_graph_unlock()) |
| 2251 | return 0; |
| 2252 | |
| 2253 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); |
| 2254 | dump_stack(); |
| 2255 | return 0; |
| 2256 | } |
| 2257 | #endif |
| 2258 | |
| 2259 | hlist_add_head_rcu(&chain->entry, hash_head); |
| 2260 | debug_atomic_inc(chain_lookup_misses); |
| 2261 | inc_chains(); |
| 2262 | |
| 2263 | return 1; |
| 2264 | } |
| 2265 | |
| 2266 | /* |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2267 | * Adds a dependency chain into chain hashtable. And must be called with |
| 2268 | * graph_lock held. |
| 2269 | * |
| 2270 | * Return 0 if fail, and graph_lock is released. |
| 2271 | * Return 1 if succeed, with graph_lock held. |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2272 | */ |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2273 | static inline int add_chain_cache(struct task_struct *curr, |
| 2274 | struct held_lock *hlock, |
| 2275 | u64 chain_key) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2276 | { |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2277 | struct lock_class *class = hlock_class(hlock); |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 2278 | struct hlist_head *hash_head = chainhashentry(chain_key); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2279 | struct lock_chain *chain; |
Steven Rostedt | e0944ee | 2011-04-20 21:42:00 -0400 | [diff] [blame] | 2280 | int i, j; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2281 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2282 | /* |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2283 | * Allocate a new chain entry from the static array, and add |
| 2284 | * it to the hash: |
| 2285 | */ |
| 2286 | |
| 2287 | /* |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2288 | * We might need to take the graph lock, ensure we've got IRQs |
| 2289 | * disabled to make this an IRQ-safe lock.. for recursion reasons |
| 2290 | * lockdep won't complain about its own locking errors. |
| 2291 | */ |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 2292 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2293 | return 0; |
Ingo Molnar | 9e4e755 | 2016-02-29 10:03:58 +0100 | [diff] [blame] | 2294 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2295 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 2296 | if (!debug_locks_off_graph_unlock()) |
| 2297 | return 0; |
| 2298 | |
Dave Jones | 2c52283 | 2013-04-25 13:40:02 -0400 | [diff] [blame] | 2299 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!"); |
Peter Zijlstra | eedeeab | 2009-03-18 12:38:47 +0100 | [diff] [blame] | 2300 | dump_stack(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2301 | return 0; |
| 2302 | } |
| 2303 | chain = lock_chains + nr_lock_chains++; |
| 2304 | chain->chain_key = chain_key; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2305 | chain->irq_context = hlock->irq_context; |
Ingo Molnar | 9e4e755 | 2016-02-29 10:03:58 +0100 | [diff] [blame] | 2306 | i = get_first_held_lock(curr, hlock); |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2307 | chain->depth = curr->lockdep_depth + 1 - i; |
Peter Zijlstra | 75dd602 | 2016-03-30 11:36:59 +0200 | [diff] [blame] | 2308 | |
| 2309 | BUILD_BUG_ON((1UL << 24) <= ARRAY_SIZE(chain_hlocks)); |
| 2310 | BUILD_BUG_ON((1UL << 6) <= ARRAY_SIZE(curr->held_locks)); |
| 2311 | BUILD_BUG_ON((1UL << 8*sizeof(chain_hlocks[0])) <= ARRAY_SIZE(lock_classes)); |
| 2312 | |
Steven Rostedt | e0944ee | 2011-04-20 21:42:00 -0400 | [diff] [blame] | 2313 | if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
| 2314 | chain->base = nr_chain_hlocks; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2315 | for (j = 0; j < chain->depth - 1; j++, i++) { |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2316 | int lock_id = curr->held_locks[i].class_idx - 1; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2317 | chain_hlocks[chain->base + j] = lock_id; |
| 2318 | } |
| 2319 | chain_hlocks[chain->base + j] = class - lock_classes; |
| 2320 | } |
Peter Zijlstra | 75dd602 | 2016-03-30 11:36:59 +0200 | [diff] [blame] | 2321 | |
| 2322 | if (nr_chain_hlocks < MAX_LOCKDEP_CHAIN_HLOCKS) |
| 2323 | nr_chain_hlocks += chain->depth; |
| 2324 | |
| 2325 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 2326 | /* |
| 2327 | * Important for check_no_collision(). |
| 2328 | */ |
| 2329 | if (unlikely(nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)) { |
Byungchul Park | f9af456 | 2017-01-13 11:42:04 +0900 | [diff] [blame] | 2330 | if (!debug_locks_off_graph_unlock()) |
Peter Zijlstra | 75dd602 | 2016-03-30 11:36:59 +0200 | [diff] [blame] | 2331 | return 0; |
| 2332 | |
| 2333 | print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!"); |
| 2334 | dump_stack(); |
| 2335 | return 0; |
| 2336 | } |
| 2337 | #endif |
| 2338 | |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 2339 | hlist_add_head_rcu(&chain->entry, hash_head); |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2340 | debug_atomic_inc(chain_lookup_misses); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2341 | inc_chains(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2342 | |
| 2343 | return 1; |
| 2344 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2345 | |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2346 | /* |
| 2347 | * Look up a dependency chain. |
| 2348 | */ |
| 2349 | static inline struct lock_chain *lookup_chain_cache(u64 chain_key) |
| 2350 | { |
| 2351 | struct hlist_head *hash_head = chainhashentry(chain_key); |
| 2352 | struct lock_chain *chain; |
| 2353 | |
| 2354 | /* |
| 2355 | * We can walk it lock-free, because entries only get added |
| 2356 | * to the hash: |
| 2357 | */ |
| 2358 | hlist_for_each_entry_rcu(chain, hash_head, entry) { |
| 2359 | if (chain->chain_key == chain_key) { |
| 2360 | debug_atomic_inc(chain_lookup_hits); |
| 2361 | return chain; |
| 2362 | } |
| 2363 | } |
| 2364 | return NULL; |
| 2365 | } |
| 2366 | |
| 2367 | /* |
| 2368 | * If the key is not present yet in dependency chain cache then |
| 2369 | * add it and return 1 - in this case the new dependency chain is |
| 2370 | * validated. If the key is already hashed, return 0. |
| 2371 | * (On return with 1 graph_lock is held.) |
| 2372 | */ |
| 2373 | static inline int lookup_chain_cache_add(struct task_struct *curr, |
| 2374 | struct held_lock *hlock, |
| 2375 | u64 chain_key) |
| 2376 | { |
| 2377 | struct lock_class *class = hlock_class(hlock); |
| 2378 | struct lock_chain *chain = lookup_chain_cache(chain_key); |
| 2379 | |
| 2380 | if (chain) { |
| 2381 | cache_hit: |
| 2382 | if (!check_no_collision(curr, hlock, chain)) |
| 2383 | return 0; |
| 2384 | |
| 2385 | if (very_verbose(class)) { |
| 2386 | printk("\nhash chain already cached, key: " |
| 2387 | "%016Lx tail class: [%p] %s\n", |
| 2388 | (unsigned long long)chain_key, |
| 2389 | class->key, class->name); |
| 2390 | } |
| 2391 | |
| 2392 | return 0; |
| 2393 | } |
| 2394 | |
| 2395 | if (very_verbose(class)) { |
| 2396 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
| 2397 | (unsigned long long)chain_key, class->key, class->name); |
| 2398 | } |
| 2399 | |
| 2400 | if (!graph_lock()) |
| 2401 | return 0; |
| 2402 | |
| 2403 | /* |
| 2404 | * We have to walk the chain again locked - to avoid duplicates: |
| 2405 | */ |
| 2406 | chain = lookup_chain_cache(chain_key); |
| 2407 | if (chain) { |
| 2408 | graph_unlock(); |
| 2409 | goto cache_hit; |
| 2410 | } |
| 2411 | |
| 2412 | if (!add_chain_cache(curr, hlock, chain_key)) |
| 2413 | return 0; |
| 2414 | |
| 2415 | return 1; |
| 2416 | } |
| 2417 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2418 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, |
Johannes Berg | 4e6045f | 2007-10-18 23:39:55 -0700 | [diff] [blame] | 2419 | struct held_lock *hlock, int chain_head, u64 chain_key) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2420 | { |
| 2421 | /* |
| 2422 | * Trylock needs to maintain the stack of held locks, but it |
| 2423 | * does not add new dependencies, because trylock can be done |
| 2424 | * in any order. |
| 2425 | * |
| 2426 | * We look up the chain_key and do the O(N^2) check and update of |
| 2427 | * the dependencies only if this is a new dependency chain. |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2428 | * (If lookup_chain_cache_add() return with 1 it acquires |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2429 | * graph_lock for us) |
| 2430 | */ |
Oleg Nesterov | fb9edbe | 2014-01-20 19:20:06 +0100 | [diff] [blame] | 2431 | if (!hlock->trylock && hlock->check && |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2432 | lookup_chain_cache_add(curr, hlock, chain_key)) { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2433 | /* |
| 2434 | * Check whether last held lock: |
| 2435 | * |
| 2436 | * - is irq-safe, if this lock is irq-unsafe |
| 2437 | * - is softirq-safe, if this lock is hardirq-unsafe |
| 2438 | * |
| 2439 | * And check whether the new lock's dependency graph |
| 2440 | * could lead back to the previous lock. |
| 2441 | * |
| 2442 | * any of these scenarios could lead to a deadlock. If |
| 2443 | * All validations |
| 2444 | */ |
| 2445 | int ret = check_deadlock(curr, hlock, lock, hlock->read); |
| 2446 | |
| 2447 | if (!ret) |
| 2448 | return 0; |
| 2449 | /* |
| 2450 | * Mark recursive read, as we jump over it when |
| 2451 | * building dependencies (just like we jump over |
| 2452 | * trylock entries): |
| 2453 | */ |
| 2454 | if (ret == 2) |
| 2455 | hlock->read = 2; |
| 2456 | /* |
| 2457 | * Add dependency only if this lock is not the head |
| 2458 | * of the chain, and if it's not a secondary read-lock: |
| 2459 | */ |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2460 | if (!chain_head && ret != 2) { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2461 | if (!check_prevs_add(curr, hlock)) |
| 2462 | return 0; |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2463 | } |
| 2464 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2465 | graph_unlock(); |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2466 | } else { |
| 2467 | /* after lookup_chain_cache_add(): */ |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2468 | if (unlikely(!debug_locks)) |
| 2469 | return 0; |
Byungchul Park | 545c23f | 2017-08-07 16:12:48 +0900 | [diff] [blame] | 2470 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2471 | |
| 2472 | return 1; |
| 2473 | } |
| 2474 | #else |
| 2475 | static inline int validate_chain(struct task_struct *curr, |
| 2476 | struct lockdep_map *lock, struct held_lock *hlock, |
Gregory Haskins | 3aa416b | 2007-10-11 22:11:11 +0200 | [diff] [blame] | 2477 | int chain_head, u64 chain_key) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2478 | { |
| 2479 | return 1; |
| 2480 | } |
Peter Zijlstra | ca58abc | 2007-07-19 01:48:53 -0700 | [diff] [blame] | 2481 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2482 | |
| 2483 | /* |
| 2484 | * We are building curr_chain_key incrementally, so double-check |
| 2485 | * it from scratch, to make sure that it's done correctly: |
| 2486 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 2487 | static void check_chain_key(struct task_struct *curr) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2488 | { |
| 2489 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 2490 | struct held_lock *hlock, *prev_hlock = NULL; |
Alfredo Alvarez Fernandez | 5f18ab5 | 2016-02-11 00:33:32 +0100 | [diff] [blame] | 2491 | unsigned int i; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2492 | u64 chain_key = 0; |
| 2493 | |
| 2494 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 2495 | hlock = curr->held_locks + i; |
| 2496 | if (chain_key != hlock->prev_chain_key) { |
| 2497 | debug_locks_off(); |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2498 | /* |
| 2499 | * We got mighty confused, our chain keys don't match |
| 2500 | * with what we expect, someone trample on our task state? |
| 2501 | */ |
Arjan van de Ven | 2df8b1d | 2008-07-30 12:43:11 -0700 | [diff] [blame] | 2502 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2503 | curr->lockdep_depth, i, |
| 2504 | (unsigned long long)chain_key, |
| 2505 | (unsigned long long)hlock->prev_chain_key); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2506 | return; |
| 2507 | } |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2508 | /* |
| 2509 | * Whoops ran out of static storage again? |
| 2510 | */ |
Alfredo Alvarez Fernandez | 5f18ab5 | 2016-02-11 00:33:32 +0100 | [diff] [blame] | 2511 | if (DEBUG_LOCKS_WARN_ON(hlock->class_idx > MAX_LOCKDEP_KEYS)) |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 2512 | return; |
| 2513 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2514 | if (prev_hlock && (prev_hlock->irq_context != |
| 2515 | hlock->irq_context)) |
| 2516 | chain_key = 0; |
Alfredo Alvarez Fernandez | 5f18ab5 | 2016-02-11 00:33:32 +0100 | [diff] [blame] | 2517 | chain_key = iterate_chain_key(chain_key, hlock->class_idx); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2518 | prev_hlock = hlock; |
| 2519 | } |
| 2520 | if (chain_key != curr->curr_chain_key) { |
| 2521 | debug_locks_off(); |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2522 | /* |
| 2523 | * More smoking hash instead of calculating it, damn see these |
| 2524 | * numbers float.. I bet that a pink elephant stepped on my memory. |
| 2525 | */ |
Arjan van de Ven | 2df8b1d | 2008-07-30 12:43:11 -0700 | [diff] [blame] | 2526 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2527 | curr->lockdep_depth, i, |
| 2528 | (unsigned long long)chain_key, |
| 2529 | (unsigned long long)curr->curr_chain_key); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2530 | } |
| 2531 | #endif |
| 2532 | } |
| 2533 | |
Steven Rostedt | 282b5c2 | 2011-04-20 21:41:59 -0400 | [diff] [blame] | 2534 | static void |
| 2535 | print_usage_bug_scenario(struct held_lock *lock) |
| 2536 | { |
| 2537 | struct lock_class *class = hlock_class(lock); |
| 2538 | |
| 2539 | printk(" Possible unsafe locking scenario:\n\n"); |
| 2540 | printk(" CPU0\n"); |
| 2541 | printk(" ----\n"); |
| 2542 | printk(" lock("); |
| 2543 | __print_lock_name(class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 2544 | printk(KERN_CONT ");\n"); |
Steven Rostedt | 282b5c2 | 2011-04-20 21:41:59 -0400 | [diff] [blame] | 2545 | printk(" <Interrupt>\n"); |
| 2546 | printk(" lock("); |
| 2547 | __print_lock_name(class); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 2548 | printk(KERN_CONT ");\n"); |
Steven Rostedt | 282b5c2 | 2011-04-20 21:41:59 -0400 | [diff] [blame] | 2549 | printk("\n *** DEADLOCK ***\n\n"); |
| 2550 | } |
| 2551 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2552 | static int |
| 2553 | print_usage_bug(struct task_struct *curr, struct held_lock *this, |
| 2554 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) |
| 2555 | { |
| 2556 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
| 2557 | return 0; |
| 2558 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2559 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 2560 | pr_warn("================================\n"); |
| 2561 | pr_warn("WARNING: inconsistent lock state\n"); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 2562 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 2563 | pr_warn("--------------------------------\n"); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2564 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2565 | pr_warn("inconsistent {%s} -> {%s} usage.\n", |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2566 | usage_str[prev_bit], usage_str[new_bit]); |
| 2567 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2568 | pr_warn("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 2569 | curr->comm, task_pid_nr(curr), |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2570 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
| 2571 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, |
| 2572 | trace_hardirqs_enabled(curr), |
| 2573 | trace_softirqs_enabled(curr)); |
| 2574 | print_lock(this); |
| 2575 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2576 | pr_warn("{%s} state was registered at:\n", usage_str[prev_bit]); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2577 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2578 | |
| 2579 | print_irqtrace_events(curr); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2580 | pr_warn("\nother info that might help us debug this:\n"); |
Steven Rostedt | 282b5c2 | 2011-04-20 21:41:59 -0400 | [diff] [blame] | 2581 | print_usage_bug_scenario(this); |
| 2582 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2583 | lockdep_print_held_locks(curr); |
| 2584 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2585 | pr_warn("\nstack backtrace:\n"); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2586 | dump_stack(); |
| 2587 | |
| 2588 | return 0; |
| 2589 | } |
| 2590 | |
| 2591 | /* |
| 2592 | * Print out an error if an invalid bit is set: |
| 2593 | */ |
| 2594 | static inline int |
| 2595 | valid_state(struct task_struct *curr, struct held_lock *this, |
| 2596 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) |
| 2597 | { |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2598 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2599 | return print_usage_bug(curr, this, bad_bit, new_bit); |
| 2600 | return 1; |
| 2601 | } |
| 2602 | |
| 2603 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
| 2604 | enum lock_usage_bit new_bit); |
| 2605 | |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2606 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2607 | |
| 2608 | /* |
| 2609 | * print irq inversion bug: |
| 2610 | */ |
| 2611 | static int |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2612 | print_irq_inversion_bug(struct task_struct *curr, |
| 2613 | struct lock_list *root, struct lock_list *other, |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2614 | struct held_lock *this, int forwards, |
| 2615 | const char *irqclass) |
| 2616 | { |
Steven Rostedt | dad3d74 | 2011-04-20 21:41:57 -0400 | [diff] [blame] | 2617 | struct lock_list *entry = other; |
| 2618 | struct lock_list *middle = NULL; |
| 2619 | int depth; |
| 2620 | |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 2621 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2622 | return 0; |
| 2623 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2624 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 2625 | pr_warn("========================================================\n"); |
| 2626 | pr_warn("WARNING: possible irq lock inversion dependency detected\n"); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 2627 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 2628 | pr_warn("--------------------------------------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2629 | pr_warn("%s/%d just changed the state of lock:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 2630 | curr->comm, task_pid_nr(curr)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2631 | print_lock(this); |
| 2632 | if (forwards) |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2633 | pr_warn("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2634 | else |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2635 | pr_warn("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2636 | print_lock_name(other->class); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2637 | pr_warn("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2638 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2639 | pr_warn("\nother info that might help us debug this:\n"); |
Steven Rostedt | dad3d74 | 2011-04-20 21:41:57 -0400 | [diff] [blame] | 2640 | |
| 2641 | /* Find a middle lock (if one exists) */ |
| 2642 | depth = get_lock_depth(other); |
| 2643 | do { |
| 2644 | if (depth == 0 && (entry != root)) { |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2645 | pr_warn("lockdep:%s bad path found in chain graph\n", __func__); |
Steven Rostedt | dad3d74 | 2011-04-20 21:41:57 -0400 | [diff] [blame] | 2646 | break; |
| 2647 | } |
| 2648 | middle = entry; |
| 2649 | entry = get_lock_parent(entry); |
| 2650 | depth--; |
| 2651 | } while (entry && entry != root && (depth >= 0)); |
| 2652 | if (forwards) |
| 2653 | print_irq_lock_scenario(root, other, |
| 2654 | middle ? middle->class : root->class, other->class); |
| 2655 | else |
| 2656 | print_irq_lock_scenario(other, root, |
| 2657 | middle ? middle->class : other->class, root->class); |
| 2658 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2659 | lockdep_print_held_locks(curr); |
| 2660 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2661 | pr_warn("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2662 | if (!save_trace(&root->trace)) |
| 2663 | return 0; |
| 2664 | print_shortest_lock_dependencies(other, root); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2665 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 2666 | pr_warn("\nstack backtrace:\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2667 | dump_stack(); |
| 2668 | |
| 2669 | return 0; |
| 2670 | } |
| 2671 | |
| 2672 | /* |
| 2673 | * Prove that in the forwards-direction subgraph starting at <this> |
| 2674 | * there is no lock matching <mask>: |
| 2675 | */ |
| 2676 | static int |
| 2677 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, |
| 2678 | enum lock_usage_bit bit, const char *irqclass) |
| 2679 | { |
| 2680 | int ret; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2681 | struct lock_list root; |
| 2682 | struct lock_list *uninitialized_var(target_entry); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2683 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2684 | root.parent = NULL; |
| 2685 | root.class = hlock_class(this); |
| 2686 | ret = find_usage_forwards(&root, bit, &target_entry); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2687 | if (ret < 0) |
| 2688 | return print_bfs_bug(ret); |
| 2689 | if (ret == 1) |
| 2690 | return ret; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2691 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2692 | return print_irq_inversion_bug(curr, &root, target_entry, |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2693 | this, 1, irqclass); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2694 | } |
| 2695 | |
| 2696 | /* |
| 2697 | * Prove that in the backwards-direction subgraph starting at <this> |
| 2698 | * there is no lock matching <mask>: |
| 2699 | */ |
| 2700 | static int |
| 2701 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, |
| 2702 | enum lock_usage_bit bit, const char *irqclass) |
| 2703 | { |
| 2704 | int ret; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2705 | struct lock_list root; |
| 2706 | struct lock_list *uninitialized_var(target_entry); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2707 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2708 | root.parent = NULL; |
| 2709 | root.class = hlock_class(this); |
| 2710 | ret = find_usage_backwards(&root, bit, &target_entry); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2711 | if (ret < 0) |
| 2712 | return print_bfs_bug(ret); |
| 2713 | if (ret == 1) |
| 2714 | return ret; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2715 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2716 | return print_irq_inversion_bug(curr, &root, target_entry, |
Oleg Nesterov | 48d5067 | 2010-01-26 19:16:41 +0100 | [diff] [blame] | 2717 | this, 0, irqclass); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2718 | } |
| 2719 | |
Ingo Molnar | 3117df0 | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 2720 | void print_irqtrace_events(struct task_struct *curr) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2721 | { |
| 2722 | printk("irq event stamp: %u\n", curr->irq_events); |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 2723 | printk("hardirqs last enabled at (%u): [<%p>] %pS\n", |
| 2724 | curr->hardirq_enable_event, (void *)curr->hardirq_enable_ip, |
| 2725 | (void *)curr->hardirq_enable_ip); |
| 2726 | printk("hardirqs last disabled at (%u): [<%p>] %pS\n", |
| 2727 | curr->hardirq_disable_event, (void *)curr->hardirq_disable_ip, |
| 2728 | (void *)curr->hardirq_disable_ip); |
| 2729 | printk("softirqs last enabled at (%u): [<%p>] %pS\n", |
| 2730 | curr->softirq_enable_event, (void *)curr->softirq_enable_ip, |
| 2731 | (void *)curr->softirq_enable_ip); |
| 2732 | printk("softirqs last disabled at (%u): [<%p>] %pS\n", |
| 2733 | curr->softirq_disable_event, (void *)curr->softirq_disable_ip, |
| 2734 | (void *)curr->softirq_disable_ip); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2735 | } |
| 2736 | |
Peter Zijlstra | cd95302 | 2009-01-22 16:38:21 +0100 | [diff] [blame] | 2737 | static int HARDIRQ_verbose(struct lock_class *class) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2738 | { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2739 | #if HARDIRQ_VERBOSE |
| 2740 | return class_filter(class); |
| 2741 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2742 | return 0; |
| 2743 | } |
| 2744 | |
Peter Zijlstra | cd95302 | 2009-01-22 16:38:21 +0100 | [diff] [blame] | 2745 | static int SOFTIRQ_verbose(struct lock_class *class) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2746 | { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2747 | #if SOFTIRQ_VERBOSE |
| 2748 | return class_filter(class); |
| 2749 | #endif |
| 2750 | return 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2751 | } |
| 2752 | |
| 2753 | #define STRICT_READ_CHECKS 1 |
| 2754 | |
Peter Zijlstra | cd95302 | 2009-01-22 16:38:21 +0100 | [diff] [blame] | 2755 | static int (*state_verbose_f[])(struct lock_class *class) = { |
| 2756 | #define LOCKDEP_STATE(__STATE) \ |
| 2757 | __STATE##_verbose, |
| 2758 | #include "lockdep_states.h" |
| 2759 | #undef LOCKDEP_STATE |
| 2760 | }; |
| 2761 | |
| 2762 | static inline int state_verbose(enum lock_usage_bit bit, |
| 2763 | struct lock_class *class) |
| 2764 | { |
| 2765 | return state_verbose_f[bit >> 2](class); |
| 2766 | } |
| 2767 | |
Peter Zijlstra | 42c50d5 | 2009-01-22 16:58:16 +0100 | [diff] [blame] | 2768 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
| 2769 | enum lock_usage_bit bit, const char *name); |
| 2770 | |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2771 | static int |
Peter Zijlstra | 1c21f14 | 2009-03-04 13:51:13 +0100 | [diff] [blame] | 2772 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
| 2773 | enum lock_usage_bit new_bit) |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2774 | { |
Peter Zijlstra | f989209 | 2009-01-22 16:09:59 +0100 | [diff] [blame] | 2775 | int excl_bit = exclusive_bit(new_bit); |
Peter Zijlstra | 9d3651a | 2009-01-22 17:18:32 +0100 | [diff] [blame] | 2776 | int read = new_bit & 1; |
Peter Zijlstra | 42c50d5 | 2009-01-22 16:58:16 +0100 | [diff] [blame] | 2777 | int dir = new_bit & 2; |
| 2778 | |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2779 | /* |
| 2780 | * mark USED_IN has to look forwards -- to ensure no dependency |
| 2781 | * has ENABLED state, which would allow recursion deadlocks. |
| 2782 | * |
| 2783 | * mark ENABLED has to look backwards -- to ensure no dependee |
| 2784 | * has USED_IN state, which, again, would allow recursion deadlocks. |
| 2785 | */ |
Peter Zijlstra | 42c50d5 | 2009-01-22 16:58:16 +0100 | [diff] [blame] | 2786 | check_usage_f usage = dir ? |
| 2787 | check_usage_backwards : check_usage_forwards; |
Peter Zijlstra | f989209 | 2009-01-22 16:09:59 +0100 | [diff] [blame] | 2788 | |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2789 | /* |
| 2790 | * Validate that this particular lock does not have conflicting |
| 2791 | * usage states. |
| 2792 | */ |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2793 | if (!valid_state(curr, this, new_bit, excl_bit)) |
| 2794 | return 0; |
Peter Zijlstra | 9d3651a | 2009-01-22 17:18:32 +0100 | [diff] [blame] | 2795 | |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2796 | /* |
| 2797 | * Validate that the lock dependencies don't have conflicting usage |
| 2798 | * states. |
| 2799 | */ |
| 2800 | if ((!read || !dir || STRICT_READ_CHECKS) && |
Peter Zijlstra | 1c21f14 | 2009-03-04 13:51:13 +0100 | [diff] [blame] | 2801 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2802 | return 0; |
Peter Zijlstra | 780e820 | 2009-01-22 16:51:29 +0100 | [diff] [blame] | 2803 | |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2804 | /* |
| 2805 | * Check for read in write conflicts |
| 2806 | */ |
| 2807 | if (!read) { |
| 2808 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) |
| 2809 | return 0; |
| 2810 | |
| 2811 | if (STRICT_READ_CHECKS && |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 2812 | !usage(curr, this, excl_bit + 1, |
| 2813 | state_name(new_bit + 1))) |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2814 | return 0; |
| 2815 | } |
Peter Zijlstra | 780e820 | 2009-01-22 16:51:29 +0100 | [diff] [blame] | 2816 | |
Peter Zijlstra | cd95302 | 2009-01-22 16:38:21 +0100 | [diff] [blame] | 2817 | if (state_verbose(new_bit, hlock_class(this))) |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2818 | return 2; |
| 2819 | |
| 2820 | return 1; |
| 2821 | } |
| 2822 | |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2823 | enum mark_type { |
Peter Zijlstra | 36bfb9b | 2009-01-22 14:12:41 +0100 | [diff] [blame] | 2824 | #define LOCKDEP_STATE(__STATE) __STATE, |
| 2825 | #include "lockdep_states.h" |
| 2826 | #undef LOCKDEP_STATE |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2827 | }; |
| 2828 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2829 | /* |
| 2830 | * Mark all held locks with a usage bit: |
| 2831 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 2832 | static int |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2833 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2834 | { |
| 2835 | enum lock_usage_bit usage_bit; |
| 2836 | struct held_lock *hlock; |
| 2837 | int i; |
| 2838 | |
| 2839 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 2840 | hlock = curr->held_locks + i; |
| 2841 | |
Peter Zijlstra | cf2ad4d | 2009-01-27 13:58:08 +0100 | [diff] [blame] | 2842 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
| 2843 | if (hlock->read) |
| 2844 | usage_bit += 1; /* READ */ |
| 2845 | |
| 2846 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2847 | |
Oleg Nesterov | 34d0ed5 | 2014-01-20 19:20:13 +0100 | [diff] [blame] | 2848 | if (!hlock->check) |
Peter Zijlstra | efbe2ee | 2011-07-07 11:39:45 +0200 | [diff] [blame] | 2849 | continue; |
| 2850 | |
Jarek Poplawski | 4ff773bb | 2007-05-08 00:31:00 -0700 | [diff] [blame] | 2851 | if (!mark_lock(curr, hlock, usage_bit)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2852 | return 0; |
| 2853 | } |
| 2854 | |
| 2855 | return 1; |
| 2856 | } |
| 2857 | |
| 2858 | /* |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2859 | * Hardirqs will be enabled: |
| 2860 | */ |
Peter Zijlstra | dd4e5d3 | 2011-06-21 17:17:27 +0200 | [diff] [blame] | 2861 | static void __trace_hardirqs_on_caller(unsigned long ip) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2862 | { |
| 2863 | struct task_struct *curr = current; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2864 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2865 | /* we'll do an OFF -> ON transition: */ |
| 2866 | curr->hardirqs_enabled = 1; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2867 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2868 | /* |
| 2869 | * We are going to turn hardirqs on, so set the |
| 2870 | * usage bit for all held locks: |
| 2871 | */ |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2872 | if (!mark_held_locks(curr, HARDIRQ)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2873 | return; |
| 2874 | /* |
| 2875 | * If we have softirqs enabled, then set the usage |
| 2876 | * bit for all held locks. (disabled hardirqs prevented |
| 2877 | * this bit from being set before) |
| 2878 | */ |
| 2879 | if (curr->softirqs_enabled) |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2880 | if (!mark_held_locks(curr, SOFTIRQ)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2881 | return; |
| 2882 | |
| 2883 | curr->hardirq_enable_ip = ip; |
| 2884 | curr->hardirq_enable_event = ++curr->irq_events; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2885 | debug_atomic_inc(hardirqs_on_events); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2886 | } |
Peter Zijlstra | dd4e5d3 | 2011-06-21 17:17:27 +0200 | [diff] [blame] | 2887 | |
Andi Kleen | b35f830 | 2014-02-08 08:52:02 +0100 | [diff] [blame] | 2888 | __visible void trace_hardirqs_on_caller(unsigned long ip) |
Peter Zijlstra | dd4e5d3 | 2011-06-21 17:17:27 +0200 | [diff] [blame] | 2889 | { |
| 2890 | time_hardirqs_on(CALLER_ADDR0, ip); |
| 2891 | |
| 2892 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
| 2893 | return; |
| 2894 | |
Peter Zijlstra | 7d36b26 | 2011-07-26 13:13:44 +0200 | [diff] [blame] | 2895 | if (unlikely(current->hardirqs_enabled)) { |
| 2896 | /* |
| 2897 | * Neither irq nor preemption are disabled here |
| 2898 | * so this is racy by nature but losing one hit |
| 2899 | * in a stat is not a big deal. |
| 2900 | */ |
| 2901 | __debug_atomic_inc(redundant_hardirqs_on); |
| 2902 | return; |
| 2903 | } |
| 2904 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2905 | /* |
| 2906 | * We're enabling irqs and according to our state above irqs weren't |
| 2907 | * already enabled, yet we find the hardware thinks they are in fact |
| 2908 | * enabled.. someone messed up their IRQ state tracing. |
| 2909 | */ |
Peter Zijlstra | dd4e5d3 | 2011-06-21 17:17:27 +0200 | [diff] [blame] | 2910 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2911 | return; |
| 2912 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2913 | /* |
| 2914 | * See the fine text that goes along with this variable definition. |
| 2915 | */ |
Peter Zijlstra | 7d36b26 | 2011-07-26 13:13:44 +0200 | [diff] [blame] | 2916 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
| 2917 | return; |
| 2918 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2919 | /* |
| 2920 | * Can't allow enabling interrupts while in an interrupt handler, |
| 2921 | * that's general bad form and such. Recursion, limited stack etc.. |
| 2922 | */ |
Peter Zijlstra | 7d36b26 | 2011-07-26 13:13:44 +0200 | [diff] [blame] | 2923 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
| 2924 | return; |
| 2925 | |
Peter Zijlstra | dd4e5d3 | 2011-06-21 17:17:27 +0200 | [diff] [blame] | 2926 | current->lockdep_recursion = 1; |
| 2927 | __trace_hardirqs_on_caller(ip); |
| 2928 | current->lockdep_recursion = 0; |
| 2929 | } |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2930 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2931 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 2932 | void trace_hardirqs_on(void) |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2933 | { |
| 2934 | trace_hardirqs_on_caller(CALLER_ADDR0); |
| 2935 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2936 | EXPORT_SYMBOL(trace_hardirqs_on); |
| 2937 | |
| 2938 | /* |
| 2939 | * Hardirqs were disabled: |
| 2940 | */ |
Andi Kleen | b35f830 | 2014-02-08 08:52:02 +0100 | [diff] [blame] | 2941 | __visible void trace_hardirqs_off_caller(unsigned long ip) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2942 | { |
| 2943 | struct task_struct *curr = current; |
| 2944 | |
Heiko Carstens | 6afe40b | 2008-10-28 11:14:58 +0100 | [diff] [blame] | 2945 | time_hardirqs_off(CALLER_ADDR0, ip); |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2946 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2947 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
| 2948 | return; |
| 2949 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2950 | /* |
| 2951 | * So we're supposed to get called after you mask local IRQs, but for |
| 2952 | * some reason the hardware doesn't quite think you did a proper job. |
| 2953 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2954 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2955 | return; |
| 2956 | |
| 2957 | if (curr->hardirqs_enabled) { |
| 2958 | /* |
| 2959 | * We have done an ON -> OFF transition: |
| 2960 | */ |
| 2961 | curr->hardirqs_enabled = 0; |
Heiko Carstens | 6afe40b | 2008-10-28 11:14:58 +0100 | [diff] [blame] | 2962 | curr->hardirq_disable_ip = ip; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2963 | curr->hardirq_disable_event = ++curr->irq_events; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2964 | debug_atomic_inc(hardirqs_off_events); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2965 | } else |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2966 | debug_atomic_inc(redundant_hardirqs_off); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2967 | } |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2968 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2969 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 2970 | void trace_hardirqs_off(void) |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2971 | { |
| 2972 | trace_hardirqs_off_caller(CALLER_ADDR0); |
| 2973 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2974 | EXPORT_SYMBOL(trace_hardirqs_off); |
| 2975 | |
| 2976 | /* |
| 2977 | * Softirqs will be enabled: |
| 2978 | */ |
| 2979 | void trace_softirqs_on(unsigned long ip) |
| 2980 | { |
| 2981 | struct task_struct *curr = current; |
| 2982 | |
Peter Zijlstra | dd4e5d3 | 2011-06-21 17:17:27 +0200 | [diff] [blame] | 2983 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2984 | return; |
| 2985 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 2986 | /* |
| 2987 | * We fancy IRQs being disabled here, see softirq.c, avoids |
| 2988 | * funny state and nesting things. |
| 2989 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2990 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2991 | return; |
| 2992 | |
| 2993 | if (curr->softirqs_enabled) { |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2994 | debug_atomic_inc(redundant_softirqs_on); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2995 | return; |
| 2996 | } |
| 2997 | |
Peter Zijlstra | dd4e5d3 | 2011-06-21 17:17:27 +0200 | [diff] [blame] | 2998 | current->lockdep_recursion = 1; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2999 | /* |
| 3000 | * We'll do an OFF -> ON transition: |
| 3001 | */ |
| 3002 | curr->softirqs_enabled = 1; |
| 3003 | curr->softirq_enable_ip = ip; |
| 3004 | curr->softirq_enable_event = ++curr->irq_events; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 3005 | debug_atomic_inc(softirqs_on_events); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3006 | /* |
| 3007 | * We are going to turn softirqs on, so set the |
| 3008 | * usage bit for all held locks, if hardirqs are |
| 3009 | * enabled too: |
| 3010 | */ |
| 3011 | if (curr->hardirqs_enabled) |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 3012 | mark_held_locks(curr, SOFTIRQ); |
Peter Zijlstra | dd4e5d3 | 2011-06-21 17:17:27 +0200 | [diff] [blame] | 3013 | current->lockdep_recursion = 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3014 | } |
| 3015 | |
| 3016 | /* |
| 3017 | * Softirqs were disabled: |
| 3018 | */ |
| 3019 | void trace_softirqs_off(unsigned long ip) |
| 3020 | { |
| 3021 | struct task_struct *curr = current; |
| 3022 | |
Peter Zijlstra | dd4e5d3 | 2011-06-21 17:17:27 +0200 | [diff] [blame] | 3023 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3024 | return; |
| 3025 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3026 | /* |
| 3027 | * We fancy IRQs being disabled here, see softirq.c |
| 3028 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3029 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 3030 | return; |
| 3031 | |
| 3032 | if (curr->softirqs_enabled) { |
| 3033 | /* |
| 3034 | * We have done an ON -> OFF transition: |
| 3035 | */ |
| 3036 | curr->softirqs_enabled = 0; |
| 3037 | curr->softirq_disable_ip = ip; |
| 3038 | curr->softirq_disable_event = ++curr->irq_events; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 3039 | debug_atomic_inc(softirqs_off_events); |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3040 | /* |
| 3041 | * Whoops, we wanted softirqs off, so why aren't they? |
| 3042 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3043 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
| 3044 | } else |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 3045 | debug_atomic_inc(redundant_softirqs_off); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3046 | } |
| 3047 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3048 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
| 3049 | { |
| 3050 | /* |
| 3051 | * If non-trylock use in a hardirq or softirq context, then |
| 3052 | * mark the lock as used in these contexts: |
| 3053 | */ |
| 3054 | if (!hlock->trylock) { |
| 3055 | if (hlock->read) { |
| 3056 | if (curr->hardirq_context) |
| 3057 | if (!mark_lock(curr, hlock, |
| 3058 | LOCK_USED_IN_HARDIRQ_READ)) |
| 3059 | return 0; |
| 3060 | if (curr->softirq_context) |
| 3061 | if (!mark_lock(curr, hlock, |
| 3062 | LOCK_USED_IN_SOFTIRQ_READ)) |
| 3063 | return 0; |
| 3064 | } else { |
| 3065 | if (curr->hardirq_context) |
| 3066 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) |
| 3067 | return 0; |
| 3068 | if (curr->softirq_context) |
| 3069 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) |
| 3070 | return 0; |
| 3071 | } |
| 3072 | } |
| 3073 | if (!hlock->hardirqs_off) { |
| 3074 | if (hlock->read) { |
| 3075 | if (!mark_lock(curr, hlock, |
Peter Zijlstra | 4fc95e8 | 2009-01-22 13:10:52 +0100 | [diff] [blame] | 3076 | LOCK_ENABLED_HARDIRQ_READ)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3077 | return 0; |
| 3078 | if (curr->softirqs_enabled) |
| 3079 | if (!mark_lock(curr, hlock, |
Peter Zijlstra | 4fc95e8 | 2009-01-22 13:10:52 +0100 | [diff] [blame] | 3080 | LOCK_ENABLED_SOFTIRQ_READ)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3081 | return 0; |
| 3082 | } else { |
| 3083 | if (!mark_lock(curr, hlock, |
Peter Zijlstra | 4fc95e8 | 2009-01-22 13:10:52 +0100 | [diff] [blame] | 3084 | LOCK_ENABLED_HARDIRQ)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3085 | return 0; |
| 3086 | if (curr->softirqs_enabled) |
| 3087 | if (!mark_lock(curr, hlock, |
Peter Zijlstra | 4fc95e8 | 2009-01-22 13:10:52 +0100 | [diff] [blame] | 3088 | LOCK_ENABLED_SOFTIRQ)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3089 | return 0; |
| 3090 | } |
| 3091 | } |
| 3092 | |
| 3093 | return 1; |
| 3094 | } |
| 3095 | |
Boqun Feng | c246975 | 2016-02-16 13:57:40 +0800 | [diff] [blame] | 3096 | static inline unsigned int task_irq_context(struct task_struct *task) |
| 3097 | { |
| 3098 | return 2 * !!task->hardirq_context + !!task->softirq_context; |
| 3099 | } |
| 3100 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3101 | static int separate_irq_context(struct task_struct *curr, |
| 3102 | struct held_lock *hlock) |
| 3103 | { |
| 3104 | unsigned int depth = curr->lockdep_depth; |
| 3105 | |
| 3106 | /* |
| 3107 | * Keep track of points where we cross into an interrupt context: |
| 3108 | */ |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3109 | if (depth) { |
| 3110 | struct held_lock *prev_hlock; |
| 3111 | |
| 3112 | prev_hlock = curr->held_locks + depth-1; |
| 3113 | /* |
| 3114 | * If we cross into another context, reset the |
| 3115 | * hash key (this also prevents the checking and the |
| 3116 | * adding of the dependency to 'prev'): |
| 3117 | */ |
| 3118 | if (prev_hlock->irq_context != hlock->irq_context) |
| 3119 | return 1; |
| 3120 | } |
| 3121 | return 0; |
| 3122 | } |
| 3123 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3124 | #else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3125 | |
| 3126 | static inline |
| 3127 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
| 3128 | enum lock_usage_bit new_bit) |
| 3129 | { |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3130 | WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */ |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3131 | return 1; |
| 3132 | } |
| 3133 | |
| 3134 | static inline int mark_irqflags(struct task_struct *curr, |
| 3135 | struct held_lock *hlock) |
| 3136 | { |
| 3137 | return 1; |
| 3138 | } |
| 3139 | |
Boqun Feng | c246975 | 2016-02-16 13:57:40 +0800 | [diff] [blame] | 3140 | static inline unsigned int task_irq_context(struct task_struct *task) |
| 3141 | { |
| 3142 | return 0; |
| 3143 | } |
| 3144 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3145 | static inline int separate_irq_context(struct task_struct *curr, |
| 3146 | struct held_lock *hlock) |
| 3147 | { |
| 3148 | return 0; |
| 3149 | } |
| 3150 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3151 | #endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3152 | |
| 3153 | /* |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3154 | * Mark a lock with a usage bit, and validate the state transition: |
| 3155 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 3156 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
Steven Rostedt | 0764d23 | 2008-05-12 21:20:44 +0200 | [diff] [blame] | 3157 | enum lock_usage_bit new_bit) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3158 | { |
| 3159 | unsigned int new_mask = 1 << new_bit, ret = 1; |
| 3160 | |
| 3161 | /* |
| 3162 | * If already set then do not dirty the cacheline, |
| 3163 | * nor do any checks: |
| 3164 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3165 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3166 | return 1; |
| 3167 | |
| 3168 | if (!graph_lock()) |
| 3169 | return 0; |
| 3170 | /* |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 3171 | * Make sure we didn't race: |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3172 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3173 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3174 | graph_unlock(); |
| 3175 | return 1; |
| 3176 | } |
| 3177 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3178 | hlock_class(this)->usage_mask |= new_mask; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3179 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3180 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3181 | return 0; |
| 3182 | |
| 3183 | switch (new_bit) { |
Peter Zijlstra | 5346417 | 2009-01-22 14:15:53 +0100 | [diff] [blame] | 3184 | #define LOCKDEP_STATE(__STATE) \ |
| 3185 | case LOCK_USED_IN_##__STATE: \ |
| 3186 | case LOCK_USED_IN_##__STATE##_READ: \ |
| 3187 | case LOCK_ENABLED_##__STATE: \ |
| 3188 | case LOCK_ENABLED_##__STATE##_READ: |
| 3189 | #include "lockdep_states.h" |
| 3190 | #undef LOCKDEP_STATE |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3191 | ret = mark_lock_irq(curr, this, new_bit); |
| 3192 | if (!ret) |
| 3193 | return 0; |
| 3194 | break; |
| 3195 | case LOCK_USED: |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 3196 | debug_atomic_dec(nr_unused_locks); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3197 | break; |
| 3198 | default: |
| 3199 | if (!debug_locks_off_graph_unlock()) |
| 3200 | return 0; |
| 3201 | WARN_ON(1); |
| 3202 | return 0; |
| 3203 | } |
| 3204 | |
| 3205 | graph_unlock(); |
| 3206 | |
| 3207 | /* |
| 3208 | * We must printk outside of the graph_lock: |
| 3209 | */ |
| 3210 | if (ret == 2) { |
| 3211 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); |
| 3212 | print_lock(this); |
| 3213 | print_irqtrace_events(curr); |
| 3214 | dump_stack(); |
| 3215 | } |
| 3216 | |
| 3217 | return ret; |
| 3218 | } |
| 3219 | |
| 3220 | /* |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3221 | * Initialize a lock instance's lock-class mapping info: |
| 3222 | */ |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 3223 | static void __lockdep_init_map(struct lockdep_map *lock, const char *name, |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 3224 | struct lock_class_key *key, int subclass) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3225 | { |
Yong Zhang | d3d03d4 | 2011-11-09 16:04:51 +0800 | [diff] [blame] | 3226 | int i; |
| 3227 | |
| 3228 | kmemcheck_mark_initialized(lock, sizeof(*lock)); |
| 3229 | |
| 3230 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) |
| 3231 | lock->class_cache[i] = NULL; |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 3232 | |
Peter Zijlstra | c8a2500 | 2009-04-17 09:40:49 +0200 | [diff] [blame] | 3233 | #ifdef CONFIG_LOCK_STAT |
| 3234 | lock->cpu = raw_smp_processor_id(); |
| 3235 | #endif |
| 3236 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3237 | /* |
| 3238 | * Can't be having no nameless bastards around this place! |
| 3239 | */ |
Peter Zijlstra | c8a2500 | 2009-04-17 09:40:49 +0200 | [diff] [blame] | 3240 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
| 3241 | lock->name = "NULL"; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3242 | return; |
Peter Zijlstra | c8a2500 | 2009-04-17 09:40:49 +0200 | [diff] [blame] | 3243 | } |
| 3244 | |
| 3245 | lock->name = name; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3246 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3247 | /* |
| 3248 | * No key, no joy, we need to hash something. |
| 3249 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3250 | if (DEBUG_LOCKS_WARN_ON(!key)) |
| 3251 | return; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3252 | /* |
| 3253 | * Sanity check, the lock-class key must be persistent: |
| 3254 | */ |
| 3255 | if (!static_obj(key)) { |
| 3256 | printk("BUG: key %p not in .data!\n", key); |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3257 | /* |
| 3258 | * What it says above ^^^^^, I suggest you read it. |
| 3259 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3260 | DEBUG_LOCKS_WARN_ON(1); |
| 3261 | return; |
| 3262 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3263 | lock->key = key; |
Peter Zijlstra | c8a2500 | 2009-04-17 09:40:49 +0200 | [diff] [blame] | 3264 | |
| 3265 | if (unlikely(!debug_locks)) |
| 3266 | return; |
| 3267 | |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 3268 | if (subclass) { |
| 3269 | unsigned long flags; |
| 3270 | |
| 3271 | if (DEBUG_LOCKS_WARN_ON(current->lockdep_recursion)) |
| 3272 | return; |
| 3273 | |
| 3274 | raw_local_irq_save(flags); |
| 3275 | current->lockdep_recursion = 1; |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 3276 | register_lock_class(lock, subclass, 1); |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 3277 | current->lockdep_recursion = 0; |
| 3278 | raw_local_irq_restore(flags); |
| 3279 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3280 | } |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 3281 | |
| 3282 | void lockdep_init_map(struct lockdep_map *lock, const char *name, |
| 3283 | struct lock_class_key *key, int subclass) |
| 3284 | { |
| 3285 | cross_init(lock, 0); |
| 3286 | __lockdep_init_map(lock, name, key, subclass); |
| 3287 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3288 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
| 3289 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 3290 | #ifdef CONFIG_LOCKDEP_CROSSRELEASE |
| 3291 | void lockdep_init_map_crosslock(struct lockdep_map *lock, const char *name, |
| 3292 | struct lock_class_key *key, int subclass) |
| 3293 | { |
| 3294 | cross_init(lock, 1); |
| 3295 | __lockdep_init_map(lock, name, key, subclass); |
| 3296 | } |
| 3297 | EXPORT_SYMBOL_GPL(lockdep_init_map_crosslock); |
| 3298 | #endif |
| 3299 | |
Peter Zijlstra | 1704f47 | 2010-03-19 01:37:42 +0100 | [diff] [blame] | 3300 | struct lock_class_key __lockdep_no_validate__; |
Kent Overstreet | ea6749c | 2012-12-27 22:21:58 -0800 | [diff] [blame] | 3301 | EXPORT_SYMBOL_GPL(__lockdep_no_validate__); |
Peter Zijlstra | 1704f47 | 2010-03-19 01:37:42 +0100 | [diff] [blame] | 3302 | |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3303 | static int |
| 3304 | print_lock_nested_lock_not_held(struct task_struct *curr, |
| 3305 | struct held_lock *hlock, |
| 3306 | unsigned long ip) |
| 3307 | { |
| 3308 | if (!debug_locks_off()) |
| 3309 | return 0; |
| 3310 | if (debug_locks_silent) |
| 3311 | return 0; |
| 3312 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3313 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 3314 | pr_warn("==================================\n"); |
| 3315 | pr_warn("WARNING: Nested lock was not taken\n"); |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3316 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 3317 | pr_warn("----------------------------------\n"); |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3318 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3319 | pr_warn("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr)); |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3320 | print_lock(hlock); |
| 3321 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3322 | pr_warn("\nbut this task is not holding:\n"); |
| 3323 | pr_warn("%s\n", hlock->nest_lock->name); |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3324 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3325 | pr_warn("\nstack backtrace:\n"); |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3326 | dump_stack(); |
| 3327 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3328 | pr_warn("\nother info that might help us debug this:\n"); |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3329 | lockdep_print_held_locks(curr); |
| 3330 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3331 | pr_warn("\nstack backtrace:\n"); |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3332 | dump_stack(); |
| 3333 | |
| 3334 | return 0; |
| 3335 | } |
| 3336 | |
Peter Zijlstra | f831948 | 2016-11-30 14:32:25 +1100 | [diff] [blame] | 3337 | static int __lock_is_held(struct lockdep_map *lock, int read); |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3338 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3339 | /* |
| 3340 | * This gets called for every mutex_lock*()/spin_lock*() operation. |
| 3341 | * We maintain the dependency maps and validate the locking attempt: |
| 3342 | */ |
| 3343 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
| 3344 | int trylock, int read, int check, int hardirqs_off, |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3345 | struct lockdep_map *nest_lock, unsigned long ip, |
Peter Zijlstra | 21199f2 | 2015-09-16 16:10:40 +0200 | [diff] [blame] | 3346 | int references, int pin_count) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3347 | { |
| 3348 | struct task_struct *curr = current; |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 3349 | struct lock_class *class = NULL; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3350 | struct held_lock *hlock; |
Alfredo Alvarez Fernandez | 5f18ab5 | 2016-02-11 00:33:32 +0100 | [diff] [blame] | 3351 | unsigned int depth; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3352 | int chain_head = 0; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3353 | int class_idx; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3354 | u64 chain_key; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 3355 | int ret; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3356 | |
| 3357 | if (unlikely(!debug_locks)) |
| 3358 | return 0; |
| 3359 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3360 | /* |
| 3361 | * Lockdep should run with IRQs disabled, otherwise we could |
| 3362 | * get an interrupt which would want to take locks, which would |
| 3363 | * end up in lockdep and have you got a head-ache already? |
| 3364 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3365 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 3366 | return 0; |
| 3367 | |
Oleg Nesterov | fb9edbe | 2014-01-20 19:20:06 +0100 | [diff] [blame] | 3368 | if (!prove_locking || lock->key == &__lockdep_no_validate__) |
| 3369 | check = 0; |
Peter Zijlstra | 1704f47 | 2010-03-19 01:37:42 +0100 | [diff] [blame] | 3370 | |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 3371 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
| 3372 | class = lock->class_cache[subclass]; |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 3373 | /* |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 3374 | * Not cached? |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 3375 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3376 | if (unlikely(!class)) { |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 3377 | class = register_lock_class(lock, subclass, 0); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3378 | if (!class) |
| 3379 | return 0; |
| 3380 | } |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 3381 | atomic_inc((atomic_t *)&class->ops); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3382 | if (very_verbose(class)) { |
| 3383 | printk("\nacquire class [%p] %s", class->key, class->name); |
| 3384 | if (class->name_version > 1) |
Dmitry Vyukov | f943fe0 | 2016-11-28 15:24:43 +0100 | [diff] [blame] | 3385 | printk(KERN_CONT "#%d", class->name_version); |
| 3386 | printk(KERN_CONT "\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3387 | dump_stack(); |
| 3388 | } |
| 3389 | |
| 3390 | /* |
| 3391 | * Add the lock to the list of currently held locks. |
| 3392 | * (we dont increase the depth just yet, up until the |
| 3393 | * dependency checks are done) |
| 3394 | */ |
| 3395 | depth = curr->lockdep_depth; |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3396 | /* |
| 3397 | * Ran out of static storage for our per-task lock stack again have we? |
| 3398 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3399 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
| 3400 | return 0; |
| 3401 | |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3402 | class_idx = class - lock_classes + 1; |
| 3403 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 3404 | /* TODO: nest_lock is not implemented for crosslock yet. */ |
| 3405 | if (depth && !cross_lock(lock)) { |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3406 | hlock = curr->held_locks + depth - 1; |
| 3407 | if (hlock->class_idx == class_idx && nest_lock) { |
Peter Zijlstra | 7fb4a2c | 2017-03-01 16:23:30 +0100 | [diff] [blame] | 3408 | if (hlock->references) { |
| 3409 | /* |
| 3410 | * Check: unsigned int references:12, overflow. |
| 3411 | */ |
| 3412 | if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1)) |
| 3413 | return 0; |
| 3414 | |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3415 | hlock->references++; |
Peter Zijlstra | 7fb4a2c | 2017-03-01 16:23:30 +0100 | [diff] [blame] | 3416 | } else { |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3417 | hlock->references = 2; |
Peter Zijlstra | 7fb4a2c | 2017-03-01 16:23:30 +0100 | [diff] [blame] | 3418 | } |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3419 | |
| 3420 | return 1; |
| 3421 | } |
| 3422 | } |
| 3423 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3424 | hlock = curr->held_locks + depth; |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3425 | /* |
| 3426 | * Plain impossible, we just registered it and checked it weren't no |
| 3427 | * NULL like.. I bet this mushroom I ate was good! |
| 3428 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3429 | if (DEBUG_LOCKS_WARN_ON(!class)) |
| 3430 | return 0; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3431 | hlock->class_idx = class_idx; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3432 | hlock->acquire_ip = ip; |
| 3433 | hlock->instance = lock; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 3434 | hlock->nest_lock = nest_lock; |
Boqun Feng | c246975 | 2016-02-16 13:57:40 +0800 | [diff] [blame] | 3435 | hlock->irq_context = task_irq_context(curr); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3436 | hlock->trylock = trylock; |
| 3437 | hlock->read = read; |
| 3438 | hlock->check = check; |
Dmitry Baryshkov | 6951b12 | 2008-08-18 04:26:37 +0400 | [diff] [blame] | 3439 | hlock->hardirqs_off = !!hardirqs_off; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3440 | hlock->references = references; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3441 | #ifdef CONFIG_LOCK_STAT |
| 3442 | hlock->waittime_stamp = 0; |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 3443 | hlock->holdtime_stamp = lockstat_clock(); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3444 | #endif |
Peter Zijlstra | 21199f2 | 2015-09-16 16:10:40 +0200 | [diff] [blame] | 3445 | hlock->pin_count = pin_count; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3446 | |
Oleg Nesterov | fb9edbe | 2014-01-20 19:20:06 +0100 | [diff] [blame] | 3447 | if (check && !mark_irqflags(curr, hlock)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3448 | return 0; |
| 3449 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3450 | /* mark it as used: */ |
Jarek Poplawski | 4ff773bb | 2007-05-08 00:31:00 -0700 | [diff] [blame] | 3451 | if (!mark_lock(curr, hlock, LOCK_USED)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3452 | return 0; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3453 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3454 | /* |
Gautham R Shenoy | 17aacfb | 2007-10-28 20:47:01 +0100 | [diff] [blame] | 3455 | * Calculate the chain hash: it's the combined hash of all the |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3456 | * lock keys along the dependency chain. We save the hash value |
| 3457 | * at every step so that we can get the current hash easily |
| 3458 | * after unlock. The chain hash is then used to cache dependency |
| 3459 | * results. |
| 3460 | * |
| 3461 | * The 'key ID' is what is the most compact key value to drive |
| 3462 | * the hash, not class->key. |
| 3463 | */ |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3464 | /* |
| 3465 | * Whoops, we did it again.. ran straight out of our static allocation. |
| 3466 | */ |
Alfredo Alvarez Fernandez | 5f18ab5 | 2016-02-11 00:33:32 +0100 | [diff] [blame] | 3467 | if (DEBUG_LOCKS_WARN_ON(class_idx > MAX_LOCKDEP_KEYS)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3468 | return 0; |
| 3469 | |
| 3470 | chain_key = curr->curr_chain_key; |
| 3471 | if (!depth) { |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3472 | /* |
| 3473 | * How can we have a chain hash when we ain't got no keys?! |
| 3474 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3475 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
| 3476 | return 0; |
| 3477 | chain_head = 1; |
| 3478 | } |
| 3479 | |
| 3480 | hlock->prev_chain_key = chain_key; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3481 | if (separate_irq_context(curr, hlock)) { |
| 3482 | chain_key = 0; |
| 3483 | chain_head = 1; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3484 | } |
Alfredo Alvarez Fernandez | 5f18ab5 | 2016-02-11 00:33:32 +0100 | [diff] [blame] | 3485 | chain_key = iterate_chain_key(chain_key, class_idx); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3486 | |
Peter Zijlstra | f831948 | 2016-11-30 14:32:25 +1100 | [diff] [blame] | 3487 | if (nest_lock && !__lock_is_held(nest_lock, -1)) |
Maarten Lankhorst | d094595 | 2012-09-13 11:39:51 +0200 | [diff] [blame] | 3488 | return print_lock_nested_lock_not_held(curr, hlock, ip); |
| 3489 | |
Gregory Haskins | 3aa416b | 2007-10-11 22:11:11 +0200 | [diff] [blame] | 3490 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 3491 | return 0; |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 3492 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 3493 | ret = lock_acquire_crosslock(hlock); |
| 3494 | /* |
| 3495 | * 2 means normal acquire operations are needed. Otherwise, it's |
| 3496 | * ok just to return with '0:fail, 1:success'. |
| 3497 | */ |
| 3498 | if (ret != 2) |
| 3499 | return ret; |
| 3500 | |
Gregory Haskins | 3aa416b | 2007-10-11 22:11:11 +0200 | [diff] [blame] | 3501 | curr->curr_chain_key = chain_key; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3502 | curr->lockdep_depth++; |
| 3503 | check_chain_key(curr); |
Jarek Poplawski | 60e114d | 2007-02-20 13:58:00 -0800 | [diff] [blame] | 3504 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 3505 | if (unlikely(!debug_locks)) |
| 3506 | return 0; |
| 3507 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3508 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
| 3509 | debug_locks_off(); |
Dave Jones | 2c52283 | 2013-04-25 13:40:02 -0400 | [diff] [blame] | 3510 | print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!"); |
| 3511 | printk(KERN_DEBUG "depth: %i max: %lu!\n", |
Ben Greear | c054060 | 2013-02-06 10:56:19 -0800 | [diff] [blame] | 3512 | curr->lockdep_depth, MAX_LOCK_DEPTH); |
Ben Greear | c054060 | 2013-02-06 10:56:19 -0800 | [diff] [blame] | 3513 | |
| 3514 | lockdep_print_held_locks(current); |
| 3515 | debug_show_all_locks(); |
Peter Zijlstra | eedeeab | 2009-03-18 12:38:47 +0100 | [diff] [blame] | 3516 | dump_stack(); |
Ben Greear | c054060 | 2013-02-06 10:56:19 -0800 | [diff] [blame] | 3517 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3518 | return 0; |
| 3519 | } |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 3520 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3521 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
| 3522 | max_lockdep_depth = curr->lockdep_depth; |
| 3523 | |
| 3524 | return 1; |
| 3525 | } |
| 3526 | |
| 3527 | static int |
Srivatsa S. Bhat | f86f755 | 2013-01-08 18:35:58 +0530 | [diff] [blame] | 3528 | print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3529 | unsigned long ip) |
| 3530 | { |
| 3531 | if (!debug_locks_off()) |
| 3532 | return 0; |
| 3533 | if (debug_locks_silent) |
| 3534 | return 0; |
| 3535 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3536 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 3537 | pr_warn("=====================================\n"); |
| 3538 | pr_warn("WARNING: bad unlock balance detected!\n"); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 3539 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 3540 | pr_warn("-------------------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3541 | pr_warn("%s/%d is trying to release lock (", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 3542 | curr->comm, task_pid_nr(curr)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3543 | print_lockdep_cache(lock); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3544 | pr_cont(") at:\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3545 | print_ip_sym(ip); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3546 | pr_warn("but there are no more locks to release!\n"); |
| 3547 | pr_warn("\nother info that might help us debug this:\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3548 | lockdep_print_held_locks(curr); |
| 3549 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 3550 | pr_warn("\nstack backtrace:\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3551 | dump_stack(); |
| 3552 | |
| 3553 | return 0; |
| 3554 | } |
| 3555 | |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3556 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
| 3557 | { |
| 3558 | if (hlock->instance == lock) |
| 3559 | return 1; |
| 3560 | |
| 3561 | if (hlock->references) { |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 3562 | struct lock_class *class = lock->class_cache[0]; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3563 | |
| 3564 | if (!class) |
| 3565 | class = look_up_lock_class(lock, 0); |
| 3566 | |
Peter Zijlstra | 80e0401 | 2011-08-05 14:26:17 +0200 | [diff] [blame] | 3567 | /* |
| 3568 | * If look_up_lock_class() failed to find a class, we're trying |
| 3569 | * to test if we hold a lock that has never yet been acquired. |
| 3570 | * Clearly if the lock hasn't been acquired _ever_, we're not |
| 3571 | * holding it either, so report failure. |
| 3572 | */ |
Thomas Gleixner | 383776f | 2017-02-27 15:37:36 +0100 | [diff] [blame] | 3573 | if (IS_ERR_OR_NULL(class)) |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3574 | return 0; |
| 3575 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3576 | /* |
| 3577 | * References, but not a lock we're actually ref-counting? |
| 3578 | * State got messed up, follow the sites that change ->references |
| 3579 | * and try to make sense of it. |
| 3580 | */ |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3581 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
| 3582 | return 0; |
| 3583 | |
| 3584 | if (hlock->class_idx == class - lock_classes + 1) |
| 3585 | return 1; |
| 3586 | } |
| 3587 | |
| 3588 | return 0; |
| 3589 | } |
| 3590 | |
J. R. Okajima | 41c2c5b | 2017-02-03 01:38:15 +0900 | [diff] [blame] | 3591 | /* @depth must not be zero */ |
| 3592 | static struct held_lock *find_held_lock(struct task_struct *curr, |
| 3593 | struct lockdep_map *lock, |
| 3594 | unsigned int depth, int *idx) |
| 3595 | { |
| 3596 | struct held_lock *ret, *hlock, *prev_hlock; |
| 3597 | int i; |
| 3598 | |
| 3599 | i = depth - 1; |
| 3600 | hlock = curr->held_locks + i; |
| 3601 | ret = hlock; |
| 3602 | if (match_held_lock(hlock, lock)) |
| 3603 | goto out; |
| 3604 | |
| 3605 | ret = NULL; |
| 3606 | for (i--, prev_hlock = hlock--; |
| 3607 | i >= 0; |
| 3608 | i--, prev_hlock = hlock--) { |
| 3609 | /* |
| 3610 | * We must not cross into another context: |
| 3611 | */ |
| 3612 | if (prev_hlock->irq_context != hlock->irq_context) { |
| 3613 | ret = NULL; |
| 3614 | break; |
| 3615 | } |
| 3616 | if (match_held_lock(hlock, lock)) { |
| 3617 | ret = hlock; |
| 3618 | break; |
| 3619 | } |
| 3620 | } |
| 3621 | |
| 3622 | out: |
| 3623 | *idx = i; |
| 3624 | return ret; |
| 3625 | } |
| 3626 | |
J. R. Okajima | e969970 | 2017-02-03 01:38:16 +0900 | [diff] [blame] | 3627 | static int reacquire_held_locks(struct task_struct *curr, unsigned int depth, |
| 3628 | int idx) |
| 3629 | { |
| 3630 | struct held_lock *hlock; |
| 3631 | |
| 3632 | for (hlock = curr->held_locks + idx; idx < depth; idx++, hlock++) { |
| 3633 | if (!__lock_acquire(hlock->instance, |
| 3634 | hlock_class(hlock)->subclass, |
| 3635 | hlock->trylock, |
| 3636 | hlock->read, hlock->check, |
| 3637 | hlock->hardirqs_off, |
| 3638 | hlock->nest_lock, hlock->acquire_ip, |
| 3639 | hlock->references, hlock->pin_count)) |
| 3640 | return 1; |
| 3641 | } |
| 3642 | return 0; |
| 3643 | } |
| 3644 | |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3645 | static int |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3646 | __lock_set_class(struct lockdep_map *lock, const char *name, |
| 3647 | struct lock_class_key *key, unsigned int subclass, |
| 3648 | unsigned long ip) |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3649 | { |
| 3650 | struct task_struct *curr = current; |
J. R. Okajima | 41c2c5b | 2017-02-03 01:38:15 +0900 | [diff] [blame] | 3651 | struct held_lock *hlock; |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3652 | struct lock_class *class; |
| 3653 | unsigned int depth; |
| 3654 | int i; |
| 3655 | |
| 3656 | depth = curr->lockdep_depth; |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3657 | /* |
| 3658 | * This function is about (re)setting the class of a held lock, |
| 3659 | * yet we're not actually holding any locks. Naughty user! |
| 3660 | */ |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3661 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
| 3662 | return 0; |
| 3663 | |
J. R. Okajima | 41c2c5b | 2017-02-03 01:38:15 +0900 | [diff] [blame] | 3664 | hlock = find_held_lock(curr, lock, depth, &i); |
| 3665 | if (!hlock) |
| 3666 | return print_unlock_imbalance_bug(curr, lock, ip); |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3667 | |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3668 | lockdep_init_map(lock, name, key, 0); |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3669 | class = register_lock_class(lock, subclass, 0); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3670 | hlock->class_idx = class - lock_classes + 1; |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3671 | |
| 3672 | curr->lockdep_depth = i; |
| 3673 | curr->curr_chain_key = hlock->prev_chain_key; |
| 3674 | |
J. R. Okajima | e969970 | 2017-02-03 01:38:16 +0900 | [diff] [blame] | 3675 | if (reacquire_held_locks(curr, depth, i)) |
| 3676 | return 0; |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3677 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3678 | /* |
| 3679 | * I took it apart and put it back together again, except now I have |
| 3680 | * these 'spare' parts.. where shall I put them. |
| 3681 | */ |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3682 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
| 3683 | return 0; |
| 3684 | return 1; |
| 3685 | } |
| 3686 | |
J. R. Okajima | 6419c4a | 2017-02-03 01:38:17 +0900 | [diff] [blame] | 3687 | static int __lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
| 3688 | { |
| 3689 | struct task_struct *curr = current; |
| 3690 | struct held_lock *hlock; |
| 3691 | unsigned int depth; |
| 3692 | int i; |
| 3693 | |
| 3694 | depth = curr->lockdep_depth; |
| 3695 | /* |
| 3696 | * This function is about (re)setting the class of a held lock, |
| 3697 | * yet we're not actually holding any locks. Naughty user! |
| 3698 | */ |
| 3699 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
| 3700 | return 0; |
| 3701 | |
| 3702 | hlock = find_held_lock(curr, lock, depth, &i); |
| 3703 | if (!hlock) |
| 3704 | return print_unlock_imbalance_bug(curr, lock, ip); |
| 3705 | |
| 3706 | curr->lockdep_depth = i; |
| 3707 | curr->curr_chain_key = hlock->prev_chain_key; |
| 3708 | |
| 3709 | WARN(hlock->read, "downgrading a read lock"); |
| 3710 | hlock->read = 1; |
| 3711 | hlock->acquire_ip = ip; |
| 3712 | |
| 3713 | if (reacquire_held_locks(curr, depth, i)) |
| 3714 | return 0; |
| 3715 | |
| 3716 | /* |
| 3717 | * I took it apart and put it back together again, except now I have |
| 3718 | * these 'spare' parts.. where shall I put them. |
| 3719 | */ |
| 3720 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
| 3721 | return 0; |
| 3722 | return 1; |
| 3723 | } |
| 3724 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3725 | /* |
Peter Zijlstra | e0f56fd | 2015-06-11 14:46:52 +0200 | [diff] [blame] | 3726 | * Remove the lock to the list of currently held locks - this gets |
| 3727 | * called on mutex_unlock()/spin_unlock*() (or on a failed |
| 3728 | * mutex_lock_interruptible()). |
| 3729 | * |
| 3730 | * @nested is an hysterical artifact, needs a tree wide cleanup. |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3731 | */ |
| 3732 | static int |
Peter Zijlstra | e0f56fd | 2015-06-11 14:46:52 +0200 | [diff] [blame] | 3733 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3734 | { |
Peter Zijlstra | e0f56fd | 2015-06-11 14:46:52 +0200 | [diff] [blame] | 3735 | struct task_struct *curr = current; |
J. R. Okajima | 41c2c5b | 2017-02-03 01:38:15 +0900 | [diff] [blame] | 3736 | struct held_lock *hlock; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3737 | unsigned int depth; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 3738 | int ret, i; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3739 | |
Peter Zijlstra | e0f56fd | 2015-06-11 14:46:52 +0200 | [diff] [blame] | 3740 | if (unlikely(!debug_locks)) |
| 3741 | return 0; |
| 3742 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 3743 | ret = lock_release_crosslock(lock); |
| 3744 | /* |
| 3745 | * 2 means normal release operations are needed. Otherwise, it's |
| 3746 | * ok just to return with '0:fail, 1:success'. |
| 3747 | */ |
| 3748 | if (ret != 2) |
| 3749 | return ret; |
| 3750 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3751 | depth = curr->lockdep_depth; |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3752 | /* |
| 3753 | * So we're all set to release this lock.. wait what lock? We don't |
| 3754 | * own any locks, you've been drinking again? |
| 3755 | */ |
Peter Zijlstra | e0f56fd | 2015-06-11 14:46:52 +0200 | [diff] [blame] | 3756 | if (DEBUG_LOCKS_WARN_ON(depth <= 0)) |
| 3757 | return print_unlock_imbalance_bug(curr, lock, ip); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3758 | |
Peter Zijlstra | e0f56fd | 2015-06-11 14:46:52 +0200 | [diff] [blame] | 3759 | /* |
| 3760 | * Check whether the lock exists in the current stack |
| 3761 | * of held locks: |
| 3762 | */ |
J. R. Okajima | 41c2c5b | 2017-02-03 01:38:15 +0900 | [diff] [blame] | 3763 | hlock = find_held_lock(curr, lock, depth, &i); |
| 3764 | if (!hlock) |
| 3765 | return print_unlock_imbalance_bug(curr, lock, ip); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3766 | |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3767 | if (hlock->instance == lock) |
| 3768 | lock_release_holdtime(hlock); |
| 3769 | |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 3770 | WARN(hlock->pin_count, "releasing a pinned lock\n"); |
| 3771 | |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3772 | if (hlock->references) { |
| 3773 | hlock->references--; |
| 3774 | if (hlock->references) { |
| 3775 | /* |
| 3776 | * We had, and after removing one, still have |
| 3777 | * references, the current lock stack is still |
| 3778 | * valid. We're done! |
| 3779 | */ |
| 3780 | return 1; |
| 3781 | } |
| 3782 | } |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3783 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3784 | /* |
| 3785 | * We have the right lock to unlock, 'hlock' points to it. |
| 3786 | * Now we remove it from the stack, and add back the other |
| 3787 | * entries (if any), recalculating the hash along the way: |
| 3788 | */ |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3789 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3790 | curr->lockdep_depth = i; |
| 3791 | curr->curr_chain_key = hlock->prev_chain_key; |
| 3792 | |
J. R. Okajima | e969970 | 2017-02-03 01:38:16 +0900 | [diff] [blame] | 3793 | if (reacquire_held_locks(curr, depth, i + 1)) |
| 3794 | return 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3795 | |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3796 | /* |
| 3797 | * We had N bottles of beer on the wall, we drank one, but now |
| 3798 | * there's not N-1 bottles of beer left on the wall... |
| 3799 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3800 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
| 3801 | return 0; |
Peter Zijlstra | e0f56fd | 2015-06-11 14:46:52 +0200 | [diff] [blame] | 3802 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3803 | return 1; |
| 3804 | } |
| 3805 | |
Peter Zijlstra | f831948 | 2016-11-30 14:32:25 +1100 | [diff] [blame] | 3806 | static int __lock_is_held(struct lockdep_map *lock, int read) |
Peter Zijlstra | f607c66 | 2009-07-20 19:16:29 +0200 | [diff] [blame] | 3807 | { |
| 3808 | struct task_struct *curr = current; |
| 3809 | int i; |
| 3810 | |
| 3811 | for (i = 0; i < curr->lockdep_depth; i++) { |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3812 | struct held_lock *hlock = curr->held_locks + i; |
| 3813 | |
Peter Zijlstra | f831948 | 2016-11-30 14:32:25 +1100 | [diff] [blame] | 3814 | if (match_held_lock(hlock, lock)) { |
| 3815 | if (read == -1 || hlock->read == read) |
| 3816 | return 1; |
| 3817 | |
| 3818 | return 0; |
| 3819 | } |
Peter Zijlstra | f607c66 | 2009-07-20 19:16:29 +0200 | [diff] [blame] | 3820 | } |
| 3821 | |
| 3822 | return 0; |
| 3823 | } |
| 3824 | |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 3825 | static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock) |
| 3826 | { |
| 3827 | struct pin_cookie cookie = NIL_COOKIE; |
| 3828 | struct task_struct *curr = current; |
| 3829 | int i; |
| 3830 | |
| 3831 | if (unlikely(!debug_locks)) |
| 3832 | return cookie; |
| 3833 | |
| 3834 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 3835 | struct held_lock *hlock = curr->held_locks + i; |
| 3836 | |
| 3837 | if (match_held_lock(hlock, lock)) { |
| 3838 | /* |
| 3839 | * Grab 16bits of randomness; this is sufficient to not |
| 3840 | * be guessable and still allows some pin nesting in |
| 3841 | * our u32 pin_count. |
| 3842 | */ |
| 3843 | cookie.val = 1 + (prandom_u32() >> 16); |
| 3844 | hlock->pin_count += cookie.val; |
| 3845 | return cookie; |
| 3846 | } |
| 3847 | } |
| 3848 | |
| 3849 | WARN(1, "pinning an unheld lock\n"); |
| 3850 | return cookie; |
| 3851 | } |
| 3852 | |
| 3853 | static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 3854 | { |
| 3855 | struct task_struct *curr = current; |
| 3856 | int i; |
| 3857 | |
| 3858 | if (unlikely(!debug_locks)) |
| 3859 | return; |
| 3860 | |
| 3861 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 3862 | struct held_lock *hlock = curr->held_locks + i; |
| 3863 | |
| 3864 | if (match_held_lock(hlock, lock)) { |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 3865 | hlock->pin_count += cookie.val; |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 3866 | return; |
| 3867 | } |
| 3868 | } |
| 3869 | |
| 3870 | WARN(1, "pinning an unheld lock\n"); |
| 3871 | } |
| 3872 | |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 3873 | static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 3874 | { |
| 3875 | struct task_struct *curr = current; |
| 3876 | int i; |
| 3877 | |
| 3878 | if (unlikely(!debug_locks)) |
| 3879 | return; |
| 3880 | |
| 3881 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 3882 | struct held_lock *hlock = curr->held_locks + i; |
| 3883 | |
| 3884 | if (match_held_lock(hlock, lock)) { |
| 3885 | if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n")) |
| 3886 | return; |
| 3887 | |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 3888 | hlock->pin_count -= cookie.val; |
| 3889 | |
| 3890 | if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n")) |
| 3891 | hlock->pin_count = 0; |
| 3892 | |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 3893 | return; |
| 3894 | } |
| 3895 | } |
| 3896 | |
| 3897 | WARN(1, "unpinning an unheld lock\n"); |
| 3898 | } |
| 3899 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3900 | /* |
| 3901 | * Check whether we follow the irq-flags state precisely: |
| 3902 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 3903 | static void check_flags(unsigned long flags) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3904 | { |
Ingo Molnar | 992860e | 2008-07-14 10:28:38 +0200 | [diff] [blame] | 3905 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
| 3906 | defined(CONFIG_TRACE_IRQFLAGS) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3907 | if (!debug_locks) |
| 3908 | return; |
| 3909 | |
Ingo Molnar | 5f9fa8a | 2007-12-07 19:02:47 +0100 | [diff] [blame] | 3910 | if (irqs_disabled_flags(flags)) { |
| 3911 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { |
| 3912 | printk("possible reason: unannotated irqs-off.\n"); |
| 3913 | } |
| 3914 | } else { |
| 3915 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { |
| 3916 | printk("possible reason: unannotated irqs-on.\n"); |
| 3917 | } |
| 3918 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3919 | |
| 3920 | /* |
| 3921 | * We dont accurately track softirq state in e.g. |
| 3922 | * hardirq contexts (such as on 4KSTACKS), so only |
| 3923 | * check if not in hardirq contexts: |
| 3924 | */ |
| 3925 | if (!hardirq_count()) { |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3926 | if (softirq_count()) { |
| 3927 | /* like the above, but with softirqs */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3928 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3929 | } else { |
| 3930 | /* lick the above, does it taste good? */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3931 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 3932 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3933 | } |
| 3934 | |
| 3935 | if (!debug_locks) |
| 3936 | print_irqtrace_events(current); |
| 3937 | #endif |
| 3938 | } |
| 3939 | |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3940 | void lock_set_class(struct lockdep_map *lock, const char *name, |
| 3941 | struct lock_class_key *key, unsigned int subclass, |
| 3942 | unsigned long ip) |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3943 | { |
| 3944 | unsigned long flags; |
| 3945 | |
| 3946 | if (unlikely(current->lockdep_recursion)) |
| 3947 | return; |
| 3948 | |
| 3949 | raw_local_irq_save(flags); |
| 3950 | current->lockdep_recursion = 1; |
| 3951 | check_flags(flags); |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3952 | if (__lock_set_class(lock, name, key, subclass, ip)) |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3953 | check_chain_key(current); |
| 3954 | current->lockdep_recursion = 0; |
| 3955 | raw_local_irq_restore(flags); |
| 3956 | } |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3957 | EXPORT_SYMBOL_GPL(lock_set_class); |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3958 | |
J. R. Okajima | 6419c4a | 2017-02-03 01:38:17 +0900 | [diff] [blame] | 3959 | void lock_downgrade(struct lockdep_map *lock, unsigned long ip) |
| 3960 | { |
| 3961 | unsigned long flags; |
| 3962 | |
| 3963 | if (unlikely(current->lockdep_recursion)) |
| 3964 | return; |
| 3965 | |
| 3966 | raw_local_irq_save(flags); |
| 3967 | current->lockdep_recursion = 1; |
| 3968 | check_flags(flags); |
| 3969 | if (__lock_downgrade(lock, ip)) |
| 3970 | check_chain_key(current); |
| 3971 | current->lockdep_recursion = 0; |
| 3972 | raw_local_irq_restore(flags); |
| 3973 | } |
| 3974 | EXPORT_SYMBOL_GPL(lock_downgrade); |
| 3975 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3976 | /* |
| 3977 | * We are not always called with irqs disabled - do that here, |
| 3978 | * and also avoid lockdep recursion: |
| 3979 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 3980 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 3981 | int trylock, int read, int check, |
| 3982 | struct lockdep_map *nest_lock, unsigned long ip) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3983 | { |
| 3984 | unsigned long flags; |
| 3985 | |
| 3986 | if (unlikely(current->lockdep_recursion)) |
| 3987 | return; |
| 3988 | |
| 3989 | raw_local_irq_save(flags); |
| 3990 | check_flags(flags); |
| 3991 | |
| 3992 | current->lockdep_recursion = 1; |
Frederic Weisbecker | db2c4c7 | 2010-02-02 23:34:40 +0100 | [diff] [blame] | 3993 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3994 | __lock_acquire(lock, subclass, trylock, read, check, |
Peter Zijlstra | 21199f2 | 2015-09-16 16:10:40 +0200 | [diff] [blame] | 3995 | irqs_disabled_flags(flags), nest_lock, ip, 0, 0); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3996 | current->lockdep_recursion = 0; |
| 3997 | raw_local_irq_restore(flags); |
| 3998 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3999 | EXPORT_SYMBOL_GPL(lock_acquire); |
| 4000 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 4001 | void lock_release(struct lockdep_map *lock, int nested, |
Steven Rostedt | 0764d23 | 2008-05-12 21:20:44 +0200 | [diff] [blame] | 4002 | unsigned long ip) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4003 | { |
| 4004 | unsigned long flags; |
| 4005 | |
| 4006 | if (unlikely(current->lockdep_recursion)) |
| 4007 | return; |
| 4008 | |
| 4009 | raw_local_irq_save(flags); |
| 4010 | check_flags(flags); |
| 4011 | current->lockdep_recursion = 1; |
Frederic Weisbecker | 9313543 | 2010-05-08 06:24:25 +0200 | [diff] [blame] | 4012 | trace_lock_release(lock, ip); |
Peter Zijlstra | e0f56fd | 2015-06-11 14:46:52 +0200 | [diff] [blame] | 4013 | if (__lock_release(lock, nested, ip)) |
| 4014 | check_chain_key(current); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4015 | current->lockdep_recursion = 0; |
| 4016 | raw_local_irq_restore(flags); |
| 4017 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4018 | EXPORT_SYMBOL_GPL(lock_release); |
| 4019 | |
Peter Zijlstra | f831948 | 2016-11-30 14:32:25 +1100 | [diff] [blame] | 4020 | int lock_is_held_type(struct lockdep_map *lock, int read) |
Peter Zijlstra | f607c66 | 2009-07-20 19:16:29 +0200 | [diff] [blame] | 4021 | { |
| 4022 | unsigned long flags; |
| 4023 | int ret = 0; |
| 4024 | |
| 4025 | if (unlikely(current->lockdep_recursion)) |
Peter Zijlstra | f2513cd | 2011-06-06 12:32:43 +0200 | [diff] [blame] | 4026 | return 1; /* avoid false negative lockdep_assert_held() */ |
Peter Zijlstra | f607c66 | 2009-07-20 19:16:29 +0200 | [diff] [blame] | 4027 | |
| 4028 | raw_local_irq_save(flags); |
| 4029 | check_flags(flags); |
| 4030 | |
| 4031 | current->lockdep_recursion = 1; |
Peter Zijlstra | f831948 | 2016-11-30 14:32:25 +1100 | [diff] [blame] | 4032 | ret = __lock_is_held(lock, read); |
Peter Zijlstra | f607c66 | 2009-07-20 19:16:29 +0200 | [diff] [blame] | 4033 | current->lockdep_recursion = 0; |
| 4034 | raw_local_irq_restore(flags); |
| 4035 | |
| 4036 | return ret; |
| 4037 | } |
Peter Zijlstra | f831948 | 2016-11-30 14:32:25 +1100 | [diff] [blame] | 4038 | EXPORT_SYMBOL_GPL(lock_is_held_type); |
Peter Zijlstra | f607c66 | 2009-07-20 19:16:29 +0200 | [diff] [blame] | 4039 | |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 4040 | struct pin_cookie lock_pin_lock(struct lockdep_map *lock) |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 4041 | { |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 4042 | struct pin_cookie cookie = NIL_COOKIE; |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 4043 | unsigned long flags; |
| 4044 | |
| 4045 | if (unlikely(current->lockdep_recursion)) |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 4046 | return cookie; |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 4047 | |
| 4048 | raw_local_irq_save(flags); |
| 4049 | check_flags(flags); |
| 4050 | |
| 4051 | current->lockdep_recursion = 1; |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 4052 | cookie = __lock_pin_lock(lock); |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 4053 | current->lockdep_recursion = 0; |
| 4054 | raw_local_irq_restore(flags); |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 4055 | |
| 4056 | return cookie; |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 4057 | } |
| 4058 | EXPORT_SYMBOL_GPL(lock_pin_lock); |
| 4059 | |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 4060 | void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 4061 | { |
| 4062 | unsigned long flags; |
| 4063 | |
| 4064 | if (unlikely(current->lockdep_recursion)) |
| 4065 | return; |
| 4066 | |
| 4067 | raw_local_irq_save(flags); |
| 4068 | check_flags(flags); |
| 4069 | |
| 4070 | current->lockdep_recursion = 1; |
Peter Zijlstra | e7904a2 | 2015-08-01 19:25:08 +0200 | [diff] [blame] | 4071 | __lock_repin_lock(lock, cookie); |
| 4072 | current->lockdep_recursion = 0; |
| 4073 | raw_local_irq_restore(flags); |
| 4074 | } |
| 4075 | EXPORT_SYMBOL_GPL(lock_repin_lock); |
| 4076 | |
| 4077 | void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie) |
| 4078 | { |
| 4079 | unsigned long flags; |
| 4080 | |
| 4081 | if (unlikely(current->lockdep_recursion)) |
| 4082 | return; |
| 4083 | |
| 4084 | raw_local_irq_save(flags); |
| 4085 | check_flags(flags); |
| 4086 | |
| 4087 | current->lockdep_recursion = 1; |
| 4088 | __lock_unpin_lock(lock, cookie); |
Peter Zijlstra | a24fc60 | 2015-06-11 14:46:53 +0200 | [diff] [blame] | 4089 | current->lockdep_recursion = 0; |
| 4090 | raw_local_irq_restore(flags); |
| 4091 | } |
| 4092 | EXPORT_SYMBOL_GPL(lock_unpin_lock); |
| 4093 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4094 | #ifdef CONFIG_LOCK_STAT |
| 4095 | static int |
| 4096 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, |
| 4097 | unsigned long ip) |
| 4098 | { |
| 4099 | if (!debug_locks_off()) |
| 4100 | return 0; |
| 4101 | if (debug_locks_silent) |
| 4102 | return 0; |
| 4103 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4104 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4105 | pr_warn("=================================\n"); |
| 4106 | pr_warn("WARNING: bad contention detected!\n"); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 4107 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4108 | pr_warn("---------------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4109 | pr_warn("%s/%d is trying to contend lock (", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 4110 | curr->comm, task_pid_nr(curr)); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4111 | print_lockdep_cache(lock); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4112 | pr_cont(") at:\n"); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4113 | print_ip_sym(ip); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4114 | pr_warn("but there are no locks held!\n"); |
| 4115 | pr_warn("\nother info that might help us debug this:\n"); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4116 | lockdep_print_held_locks(curr); |
| 4117 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4118 | pr_warn("\nstack backtrace:\n"); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4119 | dump_stack(); |
| 4120 | |
| 4121 | return 0; |
| 4122 | } |
| 4123 | |
| 4124 | static void |
| 4125 | __lock_contended(struct lockdep_map *lock, unsigned long ip) |
| 4126 | { |
| 4127 | struct task_struct *curr = current; |
J. R. Okajima | 41c2c5b | 2017-02-03 01:38:15 +0900 | [diff] [blame] | 4128 | struct held_lock *hlock; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4129 | struct lock_class_stats *stats; |
| 4130 | unsigned int depth; |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 4131 | int i, contention_point, contending_point; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4132 | |
| 4133 | depth = curr->lockdep_depth; |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 4134 | /* |
| 4135 | * Whee, we contended on this lock, except it seems we're not |
| 4136 | * actually trying to acquire anything much at all.. |
| 4137 | */ |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4138 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
| 4139 | return; |
| 4140 | |
J. R. Okajima | 41c2c5b | 2017-02-03 01:38:15 +0900 | [diff] [blame] | 4141 | hlock = find_held_lock(curr, lock, depth, &i); |
| 4142 | if (!hlock) { |
| 4143 | print_lock_contention_bug(curr, lock, ip); |
| 4144 | return; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4145 | } |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4146 | |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 4147 | if (hlock->instance != lock) |
| 4148 | return; |
| 4149 | |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 4150 | hlock->waittime_stamp = lockstat_clock(); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4151 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 4152 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
| 4153 | contending_point = lock_point(hlock_class(hlock)->contending_point, |
| 4154 | lock->ip); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4155 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 4156 | stats = get_lock_stats(hlock_class(hlock)); |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 4157 | if (contention_point < LOCKSTAT_POINTS) |
| 4158 | stats->contention_point[contention_point]++; |
| 4159 | if (contending_point < LOCKSTAT_POINTS) |
| 4160 | stats->contending_point[contending_point]++; |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 4161 | if (lock->cpu != smp_processor_id()) |
| 4162 | stats->bounces[bounce_contended + !!hlock->read]++; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4163 | put_lock_stats(stats); |
| 4164 | } |
| 4165 | |
| 4166 | static void |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 4167 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4168 | { |
| 4169 | struct task_struct *curr = current; |
J. R. Okajima | 41c2c5b | 2017-02-03 01:38:15 +0900 | [diff] [blame] | 4170 | struct held_lock *hlock; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4171 | struct lock_class_stats *stats; |
| 4172 | unsigned int depth; |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 4173 | u64 now, waittime = 0; |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 4174 | int i, cpu; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4175 | |
| 4176 | depth = curr->lockdep_depth; |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 4177 | /* |
| 4178 | * Yay, we acquired ownership of this lock we didn't try to |
| 4179 | * acquire, how the heck did that happen? |
| 4180 | */ |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4181 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
| 4182 | return; |
| 4183 | |
J. R. Okajima | 41c2c5b | 2017-02-03 01:38:15 +0900 | [diff] [blame] | 4184 | hlock = find_held_lock(curr, lock, depth, &i); |
| 4185 | if (!hlock) { |
| 4186 | print_lock_contention_bug(curr, lock, _RET_IP_); |
| 4187 | return; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4188 | } |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4189 | |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 4190 | if (hlock->instance != lock) |
| 4191 | return; |
| 4192 | |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 4193 | cpu = smp_processor_id(); |
| 4194 | if (hlock->waittime_stamp) { |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 4195 | now = lockstat_clock(); |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 4196 | waittime = now - hlock->waittime_stamp; |
| 4197 | hlock->holdtime_stamp = now; |
| 4198 | } |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4199 | |
Frederic Weisbecker | 883a2a3 | 2010-05-08 06:16:11 +0200 | [diff] [blame] | 4200 | trace_lock_acquired(lock, ip); |
Frederic Weisbecker | 2062501 | 2009-04-06 01:49:33 +0200 | [diff] [blame] | 4201 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 4202 | stats = get_lock_stats(hlock_class(hlock)); |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 4203 | if (waittime) { |
| 4204 | if (hlock->read) |
| 4205 | lock_time_inc(&stats->read_waittime, waittime); |
| 4206 | else |
| 4207 | lock_time_inc(&stats->write_waittime, waittime); |
| 4208 | } |
| 4209 | if (lock->cpu != cpu) |
| 4210 | stats->bounces[bounce_acquired + !!hlock->read]++; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4211 | put_lock_stats(stats); |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 4212 | |
| 4213 | lock->cpu = cpu; |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 4214 | lock->ip = ip; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4215 | } |
| 4216 | |
| 4217 | void lock_contended(struct lockdep_map *lock, unsigned long ip) |
| 4218 | { |
| 4219 | unsigned long flags; |
| 4220 | |
| 4221 | if (unlikely(!lock_stat)) |
| 4222 | return; |
| 4223 | |
| 4224 | if (unlikely(current->lockdep_recursion)) |
| 4225 | return; |
| 4226 | |
| 4227 | raw_local_irq_save(flags); |
| 4228 | check_flags(flags); |
| 4229 | current->lockdep_recursion = 1; |
Frederic Weisbecker | db2c4c7 | 2010-02-02 23:34:40 +0100 | [diff] [blame] | 4230 | trace_lock_contended(lock, ip); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4231 | __lock_contended(lock, ip); |
| 4232 | current->lockdep_recursion = 0; |
| 4233 | raw_local_irq_restore(flags); |
| 4234 | } |
| 4235 | EXPORT_SYMBOL_GPL(lock_contended); |
| 4236 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 4237 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4238 | { |
| 4239 | unsigned long flags; |
| 4240 | |
| 4241 | if (unlikely(!lock_stat)) |
| 4242 | return; |
| 4243 | |
| 4244 | if (unlikely(current->lockdep_recursion)) |
| 4245 | return; |
| 4246 | |
| 4247 | raw_local_irq_save(flags); |
| 4248 | check_flags(flags); |
| 4249 | current->lockdep_recursion = 1; |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 4250 | __lock_acquired(lock, ip); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 4251 | current->lockdep_recursion = 0; |
| 4252 | raw_local_irq_restore(flags); |
| 4253 | } |
| 4254 | EXPORT_SYMBOL_GPL(lock_acquired); |
| 4255 | #endif |
| 4256 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4257 | /* |
| 4258 | * Used by the testsuite, sanitize the validator state |
| 4259 | * after a simulated failure: |
| 4260 | */ |
| 4261 | |
| 4262 | void lockdep_reset(void) |
| 4263 | { |
| 4264 | unsigned long flags; |
Ingo Molnar | 23d95a0 | 2006-12-13 00:34:40 -0800 | [diff] [blame] | 4265 | int i; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4266 | |
| 4267 | raw_local_irq_save(flags); |
| 4268 | current->curr_chain_key = 0; |
| 4269 | current->lockdep_depth = 0; |
| 4270 | current->lockdep_recursion = 0; |
| 4271 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); |
| 4272 | nr_hardirq_chains = 0; |
| 4273 | nr_softirq_chains = 0; |
| 4274 | nr_process_chains = 0; |
| 4275 | debug_locks = 1; |
Ingo Molnar | 23d95a0 | 2006-12-13 00:34:40 -0800 | [diff] [blame] | 4276 | for (i = 0; i < CHAINHASH_SIZE; i++) |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 4277 | INIT_HLIST_HEAD(chainhash_table + i); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4278 | raw_local_irq_restore(flags); |
| 4279 | } |
| 4280 | |
| 4281 | static void zap_class(struct lock_class *class) |
| 4282 | { |
| 4283 | int i; |
| 4284 | |
| 4285 | /* |
| 4286 | * Remove all dependencies this lock is |
| 4287 | * involved in: |
| 4288 | */ |
| 4289 | for (i = 0; i < nr_list_entries; i++) { |
| 4290 | if (list_entries[i].class == class) |
| 4291 | list_del_rcu(&list_entries[i].entry); |
| 4292 | } |
| 4293 | /* |
| 4294 | * Unhash the class and remove it from the all_lock_classes list: |
| 4295 | */ |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 4296 | hlist_del_rcu(&class->hash_entry); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4297 | list_del_rcu(&class->lock_entry); |
| 4298 | |
Peter Zijlstra | cee34d8 | 2015-06-02 12:50:13 +0200 | [diff] [blame] | 4299 | RCU_INIT_POINTER(class->key, NULL); |
| 4300 | RCU_INIT_POINTER(class->name, NULL); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4301 | } |
| 4302 | |
Arjan van de Ven | fabe874 | 2008-01-24 07:00:45 +0100 | [diff] [blame] | 4303 | static inline int within(const void *addr, void *start, unsigned long size) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4304 | { |
| 4305 | return addr >= start && addr < start + size; |
| 4306 | } |
| 4307 | |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 4308 | /* |
| 4309 | * Used in module.c to remove lock classes from memory that is going to be |
| 4310 | * freed; and possibly re-used by other modules. |
| 4311 | * |
| 4312 | * We will have had one sync_sched() before getting here, so we're guaranteed |
| 4313 | * nobody will look up these exact classes -- they're properly dead but still |
| 4314 | * allocated. |
| 4315 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4316 | void lockdep_free_key_range(void *start, unsigned long size) |
| 4317 | { |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 4318 | struct lock_class *class; |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 4319 | struct hlist_head *head; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4320 | unsigned long flags; |
| 4321 | int i; |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 4322 | int locked; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4323 | |
| 4324 | raw_local_irq_save(flags); |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 4325 | locked = graph_lock(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4326 | |
| 4327 | /* |
| 4328 | * Unhash all classes that were created by this module: |
| 4329 | */ |
| 4330 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
| 4331 | head = classhash_table + i; |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 4332 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4333 | if (within(class->key, start, size)) |
| 4334 | zap_class(class); |
Arjan van de Ven | fabe874 | 2008-01-24 07:00:45 +0100 | [diff] [blame] | 4335 | else if (within(class->name, start, size)) |
| 4336 | zap_class(class); |
| 4337 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4338 | } |
| 4339 | |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 4340 | if (locked) |
| 4341 | graph_unlock(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4342 | raw_local_irq_restore(flags); |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 4343 | |
| 4344 | /* |
| 4345 | * Wait for any possible iterators from look_up_lock_class() to pass |
| 4346 | * before continuing to free the memory they refer to. |
| 4347 | * |
| 4348 | * sync_sched() is sufficient because the read-side is IRQ disable. |
| 4349 | */ |
| 4350 | synchronize_sched(); |
| 4351 | |
| 4352 | /* |
| 4353 | * XXX at this point we could return the resources to the pool; |
| 4354 | * instead we leak them. We would need to change to bitmap allocators |
| 4355 | * instead of the linear allocators we have now. |
| 4356 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4357 | } |
| 4358 | |
| 4359 | void lockdep_reset_lock(struct lockdep_map *lock) |
| 4360 | { |
Peter Zijlstra | 35a9393 | 2015-02-26 16:23:11 +0100 | [diff] [blame] | 4361 | struct lock_class *class; |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 4362 | struct hlist_head *head; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4363 | unsigned long flags; |
| 4364 | int i, j; |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 4365 | int locked; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4366 | |
| 4367 | raw_local_irq_save(flags); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4368 | |
| 4369 | /* |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 4370 | * Remove all classes this lock might have: |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4371 | */ |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 4372 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { |
| 4373 | /* |
| 4374 | * If the class exists we look it up and zap it: |
| 4375 | */ |
| 4376 | class = look_up_lock_class(lock, j); |
Thomas Gleixner | 383776f | 2017-02-27 15:37:36 +0100 | [diff] [blame] | 4377 | if (!IS_ERR_OR_NULL(class)) |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 4378 | zap_class(class); |
| 4379 | } |
| 4380 | /* |
| 4381 | * Debug check: in the end all mapped classes should |
| 4382 | * be gone. |
| 4383 | */ |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 4384 | locked = graph_lock(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4385 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
| 4386 | head = classhash_table + i; |
Andrew Morton | a63f38c | 2016-02-03 13:44:12 -0800 | [diff] [blame] | 4387 | hlist_for_each_entry_rcu(class, head, hash_entry) { |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 4388 | int match = 0; |
| 4389 | |
| 4390 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) |
| 4391 | match |= class == lock->class_cache[j]; |
| 4392 | |
| 4393 | if (unlikely(match)) { |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 4394 | if (debug_locks_off_graph_unlock()) { |
| 4395 | /* |
| 4396 | * We all just reset everything, how did it match? |
| 4397 | */ |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 4398 | WARN_ON(1); |
Peter Zijlstra | 0119fee | 2011-09-02 01:30:29 +0200 | [diff] [blame] | 4399 | } |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 4400 | goto out_restore; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4401 | } |
| 4402 | } |
| 4403 | } |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 4404 | if (locked) |
| 4405 | graph_unlock(); |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 4406 | |
| 4407 | out_restore: |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4408 | raw_local_irq_restore(flags); |
| 4409 | } |
| 4410 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4411 | void __init lockdep_info(void) |
| 4412 | { |
| 4413 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); |
| 4414 | |
Li Zefan | b0788ca | 2008-11-21 15:57:32 +0800 | [diff] [blame] | 4415 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4416 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
| 4417 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); |
Li Zefan | b0788ca | 2008-11-21 15:57:32 +0800 | [diff] [blame] | 4418 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4419 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
| 4420 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); |
| 4421 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); |
| 4422 | |
| 4423 | printk(" memory used by lock dependency info: %lu kB\n", |
| 4424 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + |
| 4425 | sizeof(struct list_head) * CLASSHASH_SIZE + |
| 4426 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + |
| 4427 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + |
Ming Lei | 9062920 | 2009-08-02 21:43:36 +0800 | [diff] [blame] | 4428 | sizeof(struct list_head) * CHAINHASH_SIZE |
Ming Lei | 4dd861d | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 4429 | #ifdef CONFIG_PROVE_LOCKING |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 4430 | + sizeof(struct circular_queue) |
Ming Lei | 4dd861d | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 4431 | #endif |
Ming Lei | 9062920 | 2009-08-02 21:43:36 +0800 | [diff] [blame] | 4432 | ) / 1024 |
Ming Lei | 4dd861d | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 4433 | ); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4434 | |
| 4435 | printk(" per task-struct memory footprint: %lu bytes\n", |
| 4436 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4437 | } |
| 4438 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4439 | static void |
| 4440 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, |
Arjan van de Ven | 55794a4 | 2006-07-10 04:44:03 -0700 | [diff] [blame] | 4441 | const void *mem_to, struct held_lock *hlock) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4442 | { |
| 4443 | if (!debug_locks_off()) |
| 4444 | return; |
| 4445 | if (debug_locks_silent) |
| 4446 | return; |
| 4447 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4448 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4449 | pr_warn("=========================\n"); |
| 4450 | pr_warn("WARNING: held lock freed!\n"); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 4451 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4452 | pr_warn("-------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4453 | pr_warn("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 4454 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
Arjan van de Ven | 55794a4 | 2006-07-10 04:44:03 -0700 | [diff] [blame] | 4455 | print_lock(hlock); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4456 | lockdep_print_held_locks(curr); |
| 4457 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4458 | pr_warn("\nstack backtrace:\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4459 | dump_stack(); |
| 4460 | } |
| 4461 | |
Oleg Nesterov | 5456178 | 2007-12-05 15:46:09 +0100 | [diff] [blame] | 4462 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
| 4463 | const void* lock_from, unsigned long lock_len) |
| 4464 | { |
| 4465 | return lock_from + lock_len <= mem_from || |
| 4466 | mem_from + mem_len <= lock_from; |
| 4467 | } |
| 4468 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4469 | /* |
| 4470 | * Called when kernel memory is freed (or unmapped), or if a lock |
| 4471 | * is destroyed or reinitialized - this code checks whether there is |
| 4472 | * any held lock in the memory range of <from> to <to>: |
| 4473 | */ |
| 4474 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) |
| 4475 | { |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4476 | struct task_struct *curr = current; |
| 4477 | struct held_lock *hlock; |
| 4478 | unsigned long flags; |
| 4479 | int i; |
| 4480 | |
| 4481 | if (unlikely(!debug_locks)) |
| 4482 | return; |
| 4483 | |
| 4484 | local_irq_save(flags); |
| 4485 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 4486 | hlock = curr->held_locks + i; |
| 4487 | |
Oleg Nesterov | 5456178 | 2007-12-05 15:46:09 +0100 | [diff] [blame] | 4488 | if (not_in_range(mem_from, mem_len, hlock->instance, |
| 4489 | sizeof(*hlock->instance))) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4490 | continue; |
| 4491 | |
Oleg Nesterov | 5456178 | 2007-12-05 15:46:09 +0100 | [diff] [blame] | 4492 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4493 | break; |
| 4494 | } |
| 4495 | local_irq_restore(flags); |
| 4496 | } |
Peter Zijlstra | ed07536 | 2006-12-06 20:35:24 -0800 | [diff] [blame] | 4497 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4498 | |
Colin Cross | 1b1d2fb | 2013-05-06 23:50:08 +0000 | [diff] [blame] | 4499 | static void print_held_locks_bug(void) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4500 | { |
| 4501 | if (!debug_locks_off()) |
| 4502 | return; |
| 4503 | if (debug_locks_silent) |
| 4504 | return; |
| 4505 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4506 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4507 | pr_warn("====================================\n"); |
| 4508 | pr_warn("WARNING: %s/%d still has locks held!\n", |
Colin Cross | 1b1d2fb | 2013-05-06 23:50:08 +0000 | [diff] [blame] | 4509 | current->comm, task_pid_nr(current)); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 4510 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4511 | pr_warn("------------------------------------\n"); |
Colin Cross | 1b1d2fb | 2013-05-06 23:50:08 +0000 | [diff] [blame] | 4512 | lockdep_print_held_locks(current); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4513 | pr_warn("\nstack backtrace:\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4514 | dump_stack(); |
| 4515 | } |
| 4516 | |
Colin Cross | 1b1d2fb | 2013-05-06 23:50:08 +0000 | [diff] [blame] | 4517 | void debug_check_no_locks_held(void) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4518 | { |
Colin Cross | 1b1d2fb | 2013-05-06 23:50:08 +0000 | [diff] [blame] | 4519 | if (unlikely(current->lockdep_depth > 0)) |
| 4520 | print_held_locks_bug(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4521 | } |
Colin Cross | 1b1d2fb | 2013-05-06 23:50:08 +0000 | [diff] [blame] | 4522 | EXPORT_SYMBOL_GPL(debug_check_no_locks_held); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4523 | |
Sasha Levin | 8dce7a9 | 2013-06-13 18:41:16 -0400 | [diff] [blame] | 4524 | #ifdef __KERNEL__ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4525 | void debug_show_all_locks(void) |
| 4526 | { |
| 4527 | struct task_struct *g, *p; |
| 4528 | int count = 10; |
| 4529 | int unlock = 1; |
| 4530 | |
Jarek Poplawski | 9c35dd7 | 2007-03-22 00:11:28 -0800 | [diff] [blame] | 4531 | if (unlikely(!debug_locks)) { |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4532 | pr_warn("INFO: lockdep is turned off.\n"); |
Jarek Poplawski | 9c35dd7 | 2007-03-22 00:11:28 -0800 | [diff] [blame] | 4533 | return; |
| 4534 | } |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4535 | pr_warn("\nShowing all locks held in the system:\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4536 | |
| 4537 | /* |
| 4538 | * Here we try to get the tasklist_lock as hard as possible, |
| 4539 | * if not successful after 2 seconds we ignore it (but keep |
| 4540 | * trying). This is to enable a debug printout even if a |
| 4541 | * tasklist_lock-holding task deadlocks or crashes. |
| 4542 | */ |
| 4543 | retry: |
| 4544 | if (!read_trylock(&tasklist_lock)) { |
| 4545 | if (count == 10) |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4546 | pr_warn("hm, tasklist_lock locked, retrying... "); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4547 | if (count) { |
| 4548 | count--; |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4549 | pr_cont(" #%d", 10-count); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4550 | mdelay(200); |
| 4551 | goto retry; |
| 4552 | } |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4553 | pr_cont(" ignoring it.\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4554 | unlock = 0; |
qinghuang feng | 46fec7a | 2008-10-28 17:24:28 +0800 | [diff] [blame] | 4555 | } else { |
| 4556 | if (count != 10) |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4557 | pr_cont(" locked it.\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4558 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4559 | |
| 4560 | do_each_thread(g, p) { |
Ingo Molnar | 8568487 | 2007-12-05 15:46:09 +0100 | [diff] [blame] | 4561 | /* |
| 4562 | * It's not reliable to print a task's held locks |
| 4563 | * if it's not sleeping (or if it's not the current |
| 4564 | * task): |
| 4565 | */ |
| 4566 | if (p->state == TASK_RUNNING && p != current) |
| 4567 | continue; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4568 | if (p->lockdep_depth) |
| 4569 | lockdep_print_held_locks(p); |
| 4570 | if (!unlock) |
| 4571 | if (read_trylock(&tasklist_lock)) |
| 4572 | unlock = 1; |
| 4573 | } while_each_thread(g, p); |
| 4574 | |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4575 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4576 | pr_warn("=============================================\n\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4577 | |
| 4578 | if (unlock) |
| 4579 | read_unlock(&tasklist_lock); |
| 4580 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4581 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
Sasha Levin | 8dce7a9 | 2013-06-13 18:41:16 -0400 | [diff] [blame] | 4582 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4583 | |
Ingo Molnar | 82a1fcb | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 4584 | /* |
| 4585 | * Careful: only use this function if you are sure that |
| 4586 | * the task cannot run in parallel! |
| 4587 | */ |
John Kacur | f1b499f | 2010-08-05 17:10:53 +0200 | [diff] [blame] | 4588 | void debug_show_held_locks(struct task_struct *task) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4589 | { |
Jarek Poplawski | 9c35dd7 | 2007-03-22 00:11:28 -0800 | [diff] [blame] | 4590 | if (unlikely(!debug_locks)) { |
| 4591 | printk("INFO: lockdep is turned off.\n"); |
| 4592 | return; |
| 4593 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4594 | lockdep_print_held_locks(task); |
| 4595 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 4596 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
Peter Zijlstra | b351d16 | 2007-10-11 22:11:12 +0200 | [diff] [blame] | 4597 | |
Andi Kleen | 722a9f9 | 2014-05-02 00:44:38 +0200 | [diff] [blame] | 4598 | asmlinkage __visible void lockdep_sys_exit(void) |
Peter Zijlstra | b351d16 | 2007-10-11 22:11:12 +0200 | [diff] [blame] | 4599 | { |
| 4600 | struct task_struct *curr = current; |
| 4601 | |
| 4602 | if (unlikely(curr->lockdep_depth)) { |
| 4603 | if (!debug_locks_off()) |
| 4604 | return; |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4605 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4606 | pr_warn("================================================\n"); |
| 4607 | pr_warn("WARNING: lock held when returning to user space!\n"); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 4608 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4609 | pr_warn("------------------------------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4610 | pr_warn("%s/%d is leaving the kernel with locks still held!\n", |
Peter Zijlstra | b351d16 | 2007-10-11 22:11:12 +0200 | [diff] [blame] | 4611 | curr->comm, curr->pid); |
| 4612 | lockdep_print_held_locks(curr); |
| 4613 | } |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4614 | |
| 4615 | /* |
| 4616 | * The lock history for each syscall should be independent. So wipe the |
| 4617 | * slate clean on return to userspace. |
| 4618 | */ |
Peter Zijlstra | f52be57 | 2017-08-29 10:59:39 +0200 | [diff] [blame] | 4619 | lockdep_invariant_state(false); |
Peter Zijlstra | b351d16 | 2007-10-11 22:11:12 +0200 | [diff] [blame] | 4620 | } |
Paul E. McKenney | 0632eb3 | 2010-02-22 17:04:47 -0800 | [diff] [blame] | 4621 | |
Paul E. McKenney | b3fbab0 | 2011-05-24 08:31:09 -0700 | [diff] [blame] | 4622 | void lockdep_rcu_suspicious(const char *file, const int line, const char *s) |
Paul E. McKenney | 0632eb3 | 2010-02-22 17:04:47 -0800 | [diff] [blame] | 4623 | { |
| 4624 | struct task_struct *curr = current; |
| 4625 | |
Lai Jiangshan | 2b3fc35 | 2010-04-20 16:23:07 +0800 | [diff] [blame] | 4626 | /* Note: the following can be executed concurrently, so be careful. */ |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4627 | pr_warn("\n"); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4628 | pr_warn("=============================\n"); |
| 4629 | pr_warn("WARNING: suspicious RCU usage\n"); |
Ben Hutchings | fbdc4b9 | 2011-10-28 04:36:55 +0100 | [diff] [blame] | 4630 | print_kernel_ident(); |
Paul E. McKenney | a5dd63e | 2017-01-31 07:45:13 -0800 | [diff] [blame] | 4631 | pr_warn("-----------------------------\n"); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4632 | pr_warn("%s:%d %s!\n", file, line, s); |
| 4633 | pr_warn("\nother info that might help us debug this:\n\n"); |
| 4634 | pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n", |
Paul E. McKenney | c5fdcec | 2012-01-30 08:46:32 -0800 | [diff] [blame] | 4635 | !rcu_lockdep_current_cpu_online() |
| 4636 | ? "RCU used illegally from offline CPU!\n" |
Paul E. McKenney | 5c173eb | 2013-09-13 17:20:11 -0700 | [diff] [blame] | 4637 | : !rcu_is_watching() |
Paul E. McKenney | c5fdcec | 2012-01-30 08:46:32 -0800 | [diff] [blame] | 4638 | ? "RCU used illegally from idle CPU!\n" |
| 4639 | : "", |
| 4640 | rcu_scheduler_active, debug_locks); |
Frederic Weisbecker | 0464e93 | 2011-10-07 18:22:01 +0200 | [diff] [blame] | 4641 | |
| 4642 | /* |
| 4643 | * If a CPU is in the RCU-free window in idle (ie: in the section |
| 4644 | * between rcu_idle_enter() and rcu_idle_exit(), then RCU |
| 4645 | * considers that CPU to be in an "extended quiescent state", |
| 4646 | * which means that RCU will be completely ignoring that CPU. |
| 4647 | * Therefore, rcu_read_lock() and friends have absolutely no |
| 4648 | * effect on a CPU running in that state. In other words, even if |
| 4649 | * such an RCU-idle CPU has called rcu_read_lock(), RCU might well |
| 4650 | * delete data structures out from under it. RCU really has no |
| 4651 | * choice here: we need to keep an RCU-free window in idle where |
| 4652 | * the CPU may possibly enter into low power mode. This way we can |
| 4653 | * notice an extended quiescent state to other CPUs that started a grace |
| 4654 | * period. Otherwise we would delay any grace period as long as we run |
| 4655 | * in the idle task. |
| 4656 | * |
| 4657 | * So complain bitterly if someone does call rcu_read_lock(), |
| 4658 | * rcu_read_lock_bh() and so on from extended quiescent states. |
| 4659 | */ |
Paul E. McKenney | 5c173eb | 2013-09-13 17:20:11 -0700 | [diff] [blame] | 4660 | if (!rcu_is_watching()) |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4661 | pr_warn("RCU used illegally from extended quiescent state!\n"); |
Frederic Weisbecker | 0464e93 | 2011-10-07 18:22:01 +0200 | [diff] [blame] | 4662 | |
Paul E. McKenney | 0632eb3 | 2010-02-22 17:04:47 -0800 | [diff] [blame] | 4663 | lockdep_print_held_locks(curr); |
Paul E. McKenney | 681fbec | 2017-05-04 15:44:38 -0700 | [diff] [blame] | 4664 | pr_warn("\nstack backtrace:\n"); |
Paul E. McKenney | 0632eb3 | 2010-02-22 17:04:47 -0800 | [diff] [blame] | 4665 | dump_stack(); |
| 4666 | } |
Paul E. McKenney | b3fbab0 | 2011-05-24 08:31:09 -0700 | [diff] [blame] | 4667 | EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious); |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4668 | |
| 4669 | #ifdef CONFIG_LOCKDEP_CROSSRELEASE |
| 4670 | |
| 4671 | /* |
| 4672 | * Crossrelease works by recording a lock history for each thread and |
| 4673 | * connecting those historic locks that were taken after the |
| 4674 | * wait_for_completion() in the complete() context. |
| 4675 | * |
| 4676 | * Task-A Task-B |
| 4677 | * |
| 4678 | * mutex_lock(&A); |
| 4679 | * mutex_unlock(&A); |
| 4680 | * |
| 4681 | * wait_for_completion(&C); |
| 4682 | * lock_acquire_crosslock(); |
| 4683 | * atomic_inc_return(&cross_gen_id); |
| 4684 | * | |
| 4685 | * | mutex_lock(&B); |
| 4686 | * | mutex_unlock(&B); |
| 4687 | * | |
| 4688 | * | complete(&C); |
| 4689 | * `-- lock_commit_crosslock(); |
| 4690 | * |
| 4691 | * Which will then add a dependency between B and C. |
| 4692 | */ |
| 4693 | |
| 4694 | #define xhlock(i) (current->xhlocks[(i) % MAX_XHLOCKS_NR]) |
| 4695 | |
| 4696 | /* |
| 4697 | * Whenever a crosslock is held, cross_gen_id will be increased. |
| 4698 | */ |
| 4699 | static atomic_t cross_gen_id; /* Can be wrapped */ |
| 4700 | |
| 4701 | /* |
Byungchul Park | 23f873d | 2017-08-07 16:12:53 +0900 | [diff] [blame] | 4702 | * Make an entry of the ring buffer invalid. |
| 4703 | */ |
| 4704 | static inline void invalidate_xhlock(struct hist_lock *xhlock) |
| 4705 | { |
| 4706 | /* |
| 4707 | * Normally, xhlock->hlock.instance must be !NULL. |
| 4708 | */ |
| 4709 | xhlock->hlock.instance = NULL; |
| 4710 | } |
| 4711 | |
| 4712 | /* |
Peter Zijlstra | f52be57 | 2017-08-29 10:59:39 +0200 | [diff] [blame] | 4713 | * Lock history stacks; we have 2 nested lock history stacks: |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4714 | * |
Peter Zijlstra | e6f3faa | 2017-08-23 13:23:30 +0200 | [diff] [blame] | 4715 | * HARD(IRQ) |
| 4716 | * SOFT(IRQ) |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4717 | * |
Peter Zijlstra | e6f3faa | 2017-08-23 13:23:30 +0200 | [diff] [blame] | 4718 | * The thing is that once we complete a HARD/SOFT IRQ the future task locks |
| 4719 | * should not depend on any of the locks observed while running the IRQ. So |
| 4720 | * what we do is rewind the history buffer and erase all our knowledge of that |
| 4721 | * temporal event. |
Peter Zijlstra | f52be57 | 2017-08-29 10:59:39 +0200 | [diff] [blame] | 4722 | */ |
| 4723 | |
| 4724 | void crossrelease_hist_start(enum xhlock_context_t c) |
| 4725 | { |
| 4726 | struct task_struct *cur = current; |
| 4727 | |
| 4728 | if (!cur->xhlocks) |
| 4729 | return; |
| 4730 | |
| 4731 | cur->xhlock_idx_hist[c] = cur->xhlock_idx; |
| 4732 | cur->hist_id_save[c] = cur->hist_id; |
| 4733 | } |
| 4734 | |
| 4735 | void crossrelease_hist_end(enum xhlock_context_t c) |
| 4736 | { |
| 4737 | struct task_struct *cur = current; |
| 4738 | |
| 4739 | if (cur->xhlocks) { |
| 4740 | unsigned int idx = cur->xhlock_idx_hist[c]; |
| 4741 | struct hist_lock *h = &xhlock(idx); |
| 4742 | |
| 4743 | cur->xhlock_idx = idx; |
| 4744 | |
| 4745 | /* Check if the ring was overwritten. */ |
| 4746 | if (h->hist_id != cur->hist_id_save[c]) |
| 4747 | invalidate_xhlock(h); |
| 4748 | } |
| 4749 | } |
| 4750 | |
| 4751 | /* |
| 4752 | * lockdep_invariant_state() is used to annotate independence inside a task, to |
| 4753 | * make one task look like multiple independent 'tasks'. |
Peter Zijlstra | e6f3faa | 2017-08-23 13:23:30 +0200 | [diff] [blame] | 4754 | * |
| 4755 | * Take for instance workqueues; each work is independent of the last. The |
| 4756 | * completion of a future work does not depend on the completion of a past work |
| 4757 | * (in general). Therefore we must not carry that (lock) dependency across |
| 4758 | * works. |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4759 | * |
| 4760 | * This is true for many things; pretty much all kthreads fall into this |
Peter Zijlstra | e6f3faa | 2017-08-23 13:23:30 +0200 | [diff] [blame] | 4761 | * pattern, where they have an invariant state and future completions do not |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4762 | * depend on past completions. Its just that since they all have the 'same' |
| 4763 | * form -- the kthread does the same over and over -- it doesn't typically |
| 4764 | * matter. |
| 4765 | * |
| 4766 | * The same is true for system-calls, once a system call is completed (we've |
| 4767 | * returned to userspace) the next system call does not depend on the lock |
| 4768 | * history of the previous system call. |
Peter Zijlstra | e6f3faa | 2017-08-23 13:23:30 +0200 | [diff] [blame] | 4769 | * |
| 4770 | * They key property for independence, this invariant state, is that it must be |
| 4771 | * a point where we hold no locks and have no history. Because if we were to |
| 4772 | * hold locks, the restore at _end() would not necessarily recover it's history |
| 4773 | * entry. Similarly, independence per-definition means it does not depend on |
| 4774 | * prior state. |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4775 | */ |
Peter Zijlstra | f52be57 | 2017-08-29 10:59:39 +0200 | [diff] [blame] | 4776 | void lockdep_invariant_state(bool force) |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4777 | { |
Peter Zijlstra | e6f3faa | 2017-08-23 13:23:30 +0200 | [diff] [blame] | 4778 | /* |
| 4779 | * We call this at an invariant point, no current state, no history. |
Peter Zijlstra | f52be57 | 2017-08-29 10:59:39 +0200 | [diff] [blame] | 4780 | * Verify the former, enforce the latter. |
Peter Zijlstra | e6f3faa | 2017-08-23 13:23:30 +0200 | [diff] [blame] | 4781 | */ |
Peter Zijlstra | f52be57 | 2017-08-29 10:59:39 +0200 | [diff] [blame] | 4782 | WARN_ON_ONCE(!force && current->lockdep_depth); |
| 4783 | invalidate_xhlock(&xhlock(current->xhlock_idx)); |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4784 | } |
| 4785 | |
| 4786 | static int cross_lock(struct lockdep_map *lock) |
| 4787 | { |
| 4788 | return lock ? lock->cross : 0; |
| 4789 | } |
| 4790 | |
| 4791 | /* |
| 4792 | * This is needed to decide the relationship between wrapable variables. |
| 4793 | */ |
| 4794 | static inline int before(unsigned int a, unsigned int b) |
| 4795 | { |
| 4796 | return (int)(a - b) < 0; |
| 4797 | } |
| 4798 | |
| 4799 | static inline struct lock_class *xhlock_class(struct hist_lock *xhlock) |
| 4800 | { |
| 4801 | return hlock_class(&xhlock->hlock); |
| 4802 | } |
| 4803 | |
| 4804 | static inline struct lock_class *xlock_class(struct cross_lock *xlock) |
| 4805 | { |
| 4806 | return hlock_class(&xlock->hlock); |
| 4807 | } |
| 4808 | |
| 4809 | /* |
| 4810 | * Should we check a dependency with previous one? |
| 4811 | */ |
| 4812 | static inline int depend_before(struct held_lock *hlock) |
| 4813 | { |
| 4814 | return hlock->read != 2 && hlock->check && !hlock->trylock; |
| 4815 | } |
| 4816 | |
| 4817 | /* |
| 4818 | * Should we check a dependency with next one? |
| 4819 | */ |
| 4820 | static inline int depend_after(struct held_lock *hlock) |
| 4821 | { |
| 4822 | return hlock->read != 2 && hlock->check; |
| 4823 | } |
| 4824 | |
| 4825 | /* |
| 4826 | * Check if the xhlock is valid, which would be false if, |
| 4827 | * |
| 4828 | * 1. Has not used after initializaion yet. |
Byungchul Park | 23f873d | 2017-08-07 16:12:53 +0900 | [diff] [blame] | 4829 | * 2. Got invalidated. |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4830 | * |
| 4831 | * Remind hist_lock is implemented as a ring buffer. |
| 4832 | */ |
| 4833 | static inline int xhlock_valid(struct hist_lock *xhlock) |
| 4834 | { |
| 4835 | /* |
| 4836 | * xhlock->hlock.instance must be !NULL. |
| 4837 | */ |
| 4838 | return !!xhlock->hlock.instance; |
| 4839 | } |
| 4840 | |
| 4841 | /* |
| 4842 | * Record a hist_lock entry. |
| 4843 | * |
| 4844 | * Irq disable is only required. |
| 4845 | */ |
| 4846 | static void add_xhlock(struct held_lock *hlock) |
| 4847 | { |
| 4848 | unsigned int idx = ++current->xhlock_idx; |
| 4849 | struct hist_lock *xhlock = &xhlock(idx); |
| 4850 | |
| 4851 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 4852 | /* |
| 4853 | * This can be done locklessly because they are all task-local |
| 4854 | * state, we must however ensure IRQs are disabled. |
| 4855 | */ |
| 4856 | WARN_ON_ONCE(!irqs_disabled()); |
| 4857 | #endif |
| 4858 | |
| 4859 | /* Initialize hist_lock's members */ |
| 4860 | xhlock->hlock = *hlock; |
Byungchul Park | 907dc16 | 2017-08-14 16:00:52 +0900 | [diff] [blame] | 4861 | xhlock->hist_id = ++current->hist_id; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4862 | |
| 4863 | xhlock->trace.nr_entries = 0; |
| 4864 | xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES; |
| 4865 | xhlock->trace.entries = xhlock->trace_entries; |
| 4866 | xhlock->trace.skip = 3; |
| 4867 | save_stack_trace(&xhlock->trace); |
| 4868 | } |
| 4869 | |
| 4870 | static inline int same_context_xhlock(struct hist_lock *xhlock) |
| 4871 | { |
| 4872 | return xhlock->hlock.irq_context == task_irq_context(current); |
| 4873 | } |
| 4874 | |
| 4875 | /* |
| 4876 | * This should be lockless as far as possible because this would be |
| 4877 | * called very frequently. |
| 4878 | */ |
| 4879 | static void check_add_xhlock(struct held_lock *hlock) |
| 4880 | { |
| 4881 | /* |
| 4882 | * Record a hist_lock, only in case that acquisitions ahead |
| 4883 | * could depend on the held_lock. For example, if the held_lock |
| 4884 | * is trylock then acquisitions ahead never depends on that. |
| 4885 | * In that case, we don't need to record it. Just return. |
| 4886 | */ |
| 4887 | if (!current->xhlocks || !depend_before(hlock)) |
| 4888 | return; |
| 4889 | |
| 4890 | add_xhlock(hlock); |
| 4891 | } |
| 4892 | |
| 4893 | /* |
| 4894 | * For crosslock. |
| 4895 | */ |
| 4896 | static int add_xlock(struct held_lock *hlock) |
| 4897 | { |
| 4898 | struct cross_lock *xlock; |
| 4899 | unsigned int gen_id; |
| 4900 | |
| 4901 | if (!graph_lock()) |
| 4902 | return 0; |
| 4903 | |
| 4904 | xlock = &((struct lockdep_map_cross *)hlock->instance)->xlock; |
| 4905 | |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 4906 | /* |
| 4907 | * When acquisitions for a crosslock are overlapped, we use |
| 4908 | * nr_acquire to perform commit for them, based on cross_gen_id |
| 4909 | * of the first acquisition, which allows to add additional |
| 4910 | * dependencies. |
| 4911 | * |
| 4912 | * Moreover, when no acquisition of a crosslock is in progress, |
| 4913 | * we should not perform commit because the lock might not exist |
| 4914 | * any more, which might cause incorrect memory access. So we |
| 4915 | * have to track the number of acquisitions of a crosslock. |
| 4916 | * |
| 4917 | * depend_after() is necessary to initialize only the first |
| 4918 | * valid xlock so that the xlock can be used on its commit. |
| 4919 | */ |
| 4920 | if (xlock->nr_acquire++ && depend_after(&xlock->hlock)) |
| 4921 | goto unlock; |
| 4922 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4923 | gen_id = (unsigned int)atomic_inc_return(&cross_gen_id); |
| 4924 | xlock->hlock = *hlock; |
| 4925 | xlock->hlock.gen_id = gen_id; |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 4926 | unlock: |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4927 | graph_unlock(); |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 4928 | return 1; |
| 4929 | } |
| 4930 | |
| 4931 | /* |
| 4932 | * Called for both normal and crosslock acquires. Normal locks will be |
| 4933 | * pushed on the hist_lock queue. Cross locks will record state and |
| 4934 | * stop regular lock_acquire() to avoid being placed on the held_lock |
| 4935 | * stack. |
| 4936 | * |
| 4937 | * Return: 0 - failure; |
| 4938 | * 1 - crosslock, done; |
| 4939 | * 2 - normal lock, continue to held_lock[] ops. |
| 4940 | */ |
| 4941 | static int lock_acquire_crosslock(struct held_lock *hlock) |
| 4942 | { |
| 4943 | /* |
| 4944 | * CONTEXT 1 CONTEXT 2 |
| 4945 | * --------- --------- |
| 4946 | * lock A (cross) |
| 4947 | * X = atomic_inc_return(&cross_gen_id) |
| 4948 | * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 4949 | * Y = atomic_read_acquire(&cross_gen_id) |
| 4950 | * lock B |
| 4951 | * |
| 4952 | * atomic_read_acquire() is for ordering between A and B, |
| 4953 | * IOW, A happens before B, when CONTEXT 2 see Y >= X. |
| 4954 | * |
| 4955 | * Pairs with atomic_inc_return() in add_xlock(). |
| 4956 | */ |
| 4957 | hlock->gen_id = (unsigned int)atomic_read_acquire(&cross_gen_id); |
| 4958 | |
| 4959 | if (cross_lock(hlock->instance)) |
| 4960 | return add_xlock(hlock); |
| 4961 | |
| 4962 | check_add_xhlock(hlock); |
| 4963 | return 2; |
| 4964 | } |
| 4965 | |
| 4966 | static int copy_trace(struct stack_trace *trace) |
| 4967 | { |
| 4968 | unsigned long *buf = stack_trace + nr_stack_trace_entries; |
| 4969 | unsigned int max_nr = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; |
| 4970 | unsigned int nr = min(max_nr, trace->nr_entries); |
| 4971 | |
| 4972 | trace->nr_entries = nr; |
| 4973 | memcpy(buf, trace->entries, nr * sizeof(trace->entries[0])); |
| 4974 | trace->entries = buf; |
| 4975 | nr_stack_trace_entries += nr; |
| 4976 | |
| 4977 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
| 4978 | if (!debug_locks_off_graph_unlock()) |
| 4979 | return 0; |
| 4980 | |
| 4981 | print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!"); |
| 4982 | dump_stack(); |
| 4983 | |
| 4984 | return 0; |
| 4985 | } |
| 4986 | |
| 4987 | return 1; |
| 4988 | } |
| 4989 | |
| 4990 | static int commit_xhlock(struct cross_lock *xlock, struct hist_lock *xhlock) |
| 4991 | { |
| 4992 | unsigned int xid, pid; |
| 4993 | u64 chain_key; |
| 4994 | |
| 4995 | xid = xlock_class(xlock) - lock_classes; |
| 4996 | chain_key = iterate_chain_key((u64)0, xid); |
| 4997 | pid = xhlock_class(xhlock) - lock_classes; |
| 4998 | chain_key = iterate_chain_key(chain_key, pid); |
| 4999 | |
| 5000 | if (lookup_chain_cache(chain_key)) |
| 5001 | return 1; |
| 5002 | |
| 5003 | if (!add_chain_cache_classes(xid, pid, xhlock->hlock.irq_context, |
| 5004 | chain_key)) |
| 5005 | return 0; |
| 5006 | |
| 5007 | if (!check_prev_add(current, &xlock->hlock, &xhlock->hlock, 1, |
| 5008 | &xhlock->trace, copy_trace)) |
| 5009 | return 0; |
| 5010 | |
| 5011 | return 1; |
| 5012 | } |
| 5013 | |
| 5014 | static void commit_xhlocks(struct cross_lock *xlock) |
| 5015 | { |
| 5016 | unsigned int cur = current->xhlock_idx; |
Byungchul Park | 23f873d | 2017-08-07 16:12:53 +0900 | [diff] [blame] | 5017 | unsigned int prev_hist_id = xhlock(cur).hist_id; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5018 | unsigned int i; |
| 5019 | |
| 5020 | if (!graph_lock()) |
| 5021 | return; |
| 5022 | |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5023 | if (xlock->nr_acquire) { |
| 5024 | for (i = 0; i < MAX_XHLOCKS_NR; i++) { |
| 5025 | struct hist_lock *xhlock = &xhlock(cur - i); |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5026 | |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5027 | if (!xhlock_valid(xhlock)) |
| 5028 | break; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5029 | |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5030 | if (before(xhlock->hlock.gen_id, xlock->hlock.gen_id)) |
| 5031 | break; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5032 | |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5033 | if (!same_context_xhlock(xhlock)) |
| 5034 | break; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5035 | |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5036 | /* |
Byungchul Park | 907dc16 | 2017-08-14 16:00:52 +0900 | [diff] [blame] | 5037 | * Filter out the cases where the ring buffer was |
| 5038 | * overwritten and the current entry has a bigger |
| 5039 | * hist_id than the previous one, which is impossible |
| 5040 | * otherwise: |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5041 | */ |
Byungchul Park | 907dc16 | 2017-08-14 16:00:52 +0900 | [diff] [blame] | 5042 | if (unlikely(before(prev_hist_id, xhlock->hist_id))) |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5043 | break; |
Byungchul Park | 23f873d | 2017-08-07 16:12:53 +0900 | [diff] [blame] | 5044 | |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5045 | prev_hist_id = xhlock->hist_id; |
Byungchul Park | 23f873d | 2017-08-07 16:12:53 +0900 | [diff] [blame] | 5046 | |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5047 | /* |
| 5048 | * commit_xhlock() returns 0 with graph_lock already |
| 5049 | * released if fail. |
| 5050 | */ |
| 5051 | if (!commit_xhlock(xlock, xhlock)) |
| 5052 | return; |
| 5053 | } |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5054 | } |
| 5055 | |
| 5056 | graph_unlock(); |
| 5057 | } |
| 5058 | |
| 5059 | void lock_commit_crosslock(struct lockdep_map *lock) |
| 5060 | { |
| 5061 | struct cross_lock *xlock; |
| 5062 | unsigned long flags; |
| 5063 | |
| 5064 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
| 5065 | return; |
| 5066 | |
| 5067 | if (!current->xhlocks) |
| 5068 | return; |
| 5069 | |
| 5070 | /* |
| 5071 | * Do commit hist_locks with the cross_lock, only in case that |
| 5072 | * the cross_lock could depend on acquisitions after that. |
| 5073 | * |
| 5074 | * For example, if the cross_lock does not have the 'check' flag |
| 5075 | * then we don't need to check dependencies and commit for that. |
| 5076 | * Just skip it. In that case, of course, the cross_lock does |
| 5077 | * not depend on acquisitions ahead, either. |
| 5078 | * |
| 5079 | * WARNING: Don't do that in add_xlock() in advance. When an |
| 5080 | * acquisition context is different from the commit context, |
| 5081 | * invalid(skipped) cross_lock might be accessed. |
| 5082 | */ |
| 5083 | if (!depend_after(&((struct lockdep_map_cross *)lock)->xlock.hlock)) |
| 5084 | return; |
| 5085 | |
| 5086 | raw_local_irq_save(flags); |
| 5087 | check_flags(flags); |
| 5088 | current->lockdep_recursion = 1; |
| 5089 | xlock = &((struct lockdep_map_cross *)lock)->xlock; |
| 5090 | commit_xhlocks(xlock); |
| 5091 | current->lockdep_recursion = 0; |
| 5092 | raw_local_irq_restore(flags); |
| 5093 | } |
| 5094 | EXPORT_SYMBOL_GPL(lock_commit_crosslock); |
| 5095 | |
| 5096 | /* |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5097 | * Return: 0 - failure; |
| 5098 | * 1 - crosslock, done; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5099 | * 2 - normal lock, continue to held_lock[] ops. |
| 5100 | */ |
| 5101 | static int lock_release_crosslock(struct lockdep_map *lock) |
| 5102 | { |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5103 | if (cross_lock(lock)) { |
| 5104 | if (!graph_lock()) |
| 5105 | return 0; |
| 5106 | ((struct lockdep_map_cross *)lock)->xlock.nr_acquire--; |
| 5107 | graph_unlock(); |
| 5108 | return 1; |
| 5109 | } |
| 5110 | return 2; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5111 | } |
| 5112 | |
| 5113 | static void cross_init(struct lockdep_map *lock, int cross) |
| 5114 | { |
Byungchul Park | 28a903f | 2017-08-07 16:12:54 +0900 | [diff] [blame] | 5115 | if (cross) |
| 5116 | ((struct lockdep_map_cross *)lock)->xlock.nr_acquire = 0; |
| 5117 | |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5118 | lock->cross = cross; |
| 5119 | |
| 5120 | /* |
| 5121 | * Crossrelease assumes that the ring buffer size of xhlocks |
| 5122 | * is aligned with power of 2. So force it on build. |
| 5123 | */ |
| 5124 | BUILD_BUG_ON(MAX_XHLOCKS_NR & (MAX_XHLOCKS_NR - 1)); |
| 5125 | } |
| 5126 | |
| 5127 | void lockdep_init_task(struct task_struct *task) |
| 5128 | { |
| 5129 | int i; |
| 5130 | |
| 5131 | task->xhlock_idx = UINT_MAX; |
Byungchul Park | 23f873d | 2017-08-07 16:12:53 +0900 | [diff] [blame] | 5132 | task->hist_id = 0; |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5133 | |
Byungchul Park | 23f873d | 2017-08-07 16:12:53 +0900 | [diff] [blame] | 5134 | for (i = 0; i < XHLOCK_CTX_NR; i++) { |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5135 | task->xhlock_idx_hist[i] = UINT_MAX; |
Byungchul Park | 23f873d | 2017-08-07 16:12:53 +0900 | [diff] [blame] | 5136 | task->hist_id_save[i] = 0; |
| 5137 | } |
Byungchul Park | b09be67 | 2017-08-07 16:12:52 +0900 | [diff] [blame] | 5138 | |
| 5139 | task->xhlocks = kzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR, |
| 5140 | GFP_KERNEL); |
| 5141 | } |
| 5142 | |
| 5143 | void lockdep_free_task(struct task_struct *task) |
| 5144 | { |
| 5145 | if (task->xhlocks) { |
| 5146 | void *tmp = task->xhlocks; |
| 5147 | /* Diable crossrelease for current */ |
| 5148 | task->xhlocks = NULL; |
| 5149 | kfree(tmp); |
| 5150 | } |
| 5151 | } |
| 5152 | #endif |