Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Detect hard and soft lockups on a system |
| 3 | * |
| 4 | * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc. |
| 5 | * |
Fernando Luis Vázquez Cao | 86f5e6a | 2012-02-09 17:42:22 -0500 | [diff] [blame] | 6 | * Note: Most of this code is borrowed heavily from the original softlockup |
| 7 | * detector, so thanks to Ingo for the initial implementation. |
| 8 | * Some chunks also taken from the old x86-specific nmi watchdog code, thanks |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 9 | * to those contributors as well. |
| 10 | */ |
| 11 | |
Andrew Morton | 4501980 | 2012-03-23 15:01:55 -0700 | [diff] [blame] | 12 | #define pr_fmt(fmt) "NMI watchdog: " fmt |
| 13 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 14 | #include <linux/mm.h> |
| 15 | #include <linux/cpu.h> |
| 16 | #include <linux/nmi.h> |
| 17 | #include <linux/init.h> |
| 18 | #include <linux/delay.h> |
| 19 | #include <linux/freezer.h> |
| 20 | #include <linux/kthread.h> |
| 21 | #include <linux/lockdep.h> |
| 22 | #include <linux/notifier.h> |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/sysctl.h> |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 25 | #include <linux/smpboot.h> |
Clark Williams | 8bd75c7 | 2013-02-07 09:47:07 -0600 | [diff] [blame] | 26 | #include <linux/sched/rt.h> |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 27 | |
| 28 | #include <asm/irq_regs.h> |
Eric B Munson | 5d1c0f4 | 2012-03-10 14:37:28 -0500 | [diff] [blame] | 29 | #include <linux/kvm_para.h> |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 30 | #include <linux/perf_event.h> |
| 31 | |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 32 | int watchdog_user_enabled = 1; |
Mandeep Singh Baines | 4eec42f | 2011-05-22 22:10:23 -0700 | [diff] [blame] | 33 | int __read_mostly watchdog_thresh = 10; |
Aaron Tomlin | ed23587 | 2014-06-23 13:22:05 -0700 | [diff] [blame] | 34 | #ifdef CONFIG_SMP |
| 35 | int __read_mostly sysctl_softlockup_all_cpu_backtrace; |
| 36 | #else |
| 37 | #define sysctl_softlockup_all_cpu_backtrace 0 |
| 38 | #endif |
| 39 | |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 40 | static int __read_mostly watchdog_running; |
Chuansheng Liu | 0f34c40 | 2012-12-17 15:59:50 -0800 | [diff] [blame] | 41 | static u64 __read_mostly sample_period; |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 42 | |
| 43 | static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts); |
| 44 | static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog); |
| 45 | static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer); |
| 46 | static DEFINE_PER_CPU(bool, softlockup_touch_sync); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 47 | static DEFINE_PER_CPU(bool, soft_watchdog_warn); |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 48 | static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts); |
| 49 | static DEFINE_PER_CPU(unsigned long, soft_lockup_hrtimer_cnt); |
Frederic Weisbecker | 23637d4 | 2010-05-15 23:15:20 +0200 | [diff] [blame] | 50 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
Don Zickus | cafcd80 | 2010-05-14 11:11:21 -0400 | [diff] [blame] | 51 | static DEFINE_PER_CPU(bool, hard_watchdog_warn); |
| 52 | static DEFINE_PER_CPU(bool, watchdog_nmi_touch); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 53 | static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved); |
| 54 | static DEFINE_PER_CPU(struct perf_event *, watchdog_ev); |
| 55 | #endif |
Aaron Tomlin | ed23587 | 2014-06-23 13:22:05 -0700 | [diff] [blame] | 56 | static unsigned long soft_lockup_nmi_warn; |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 57 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 58 | /* boot commands */ |
| 59 | /* |
| 60 | * Should we panic when a soft-lockup or hard-lockup occurs: |
| 61 | */ |
Frederic Weisbecker | 23637d4 | 2010-05-15 23:15:20 +0200 | [diff] [blame] | 62 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
Don Zickus | fef2c9b | 2011-03-22 16:34:16 -0700 | [diff] [blame] | 63 | static int hardlockup_panic = |
| 64 | CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE; |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 65 | |
| 66 | static int __init hardlockup_panic_setup(char *str) |
| 67 | { |
| 68 | if (!strncmp(str, "panic", 5)) |
| 69 | hardlockup_panic = 1; |
Don Zickus | fef2c9b | 2011-03-22 16:34:16 -0700 | [diff] [blame] | 70 | else if (!strncmp(str, "nopanic", 7)) |
| 71 | hardlockup_panic = 0; |
Don Zickus | 5dc3055 | 2010-11-29 17:07:17 -0500 | [diff] [blame] | 72 | else if (!strncmp(str, "0", 1)) |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 73 | watchdog_user_enabled = 0; |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 74 | return 1; |
| 75 | } |
| 76 | __setup("nmi_watchdog=", hardlockup_panic_setup); |
| 77 | #endif |
| 78 | |
| 79 | unsigned int __read_mostly softlockup_panic = |
| 80 | CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE; |
| 81 | |
| 82 | static int __init softlockup_panic_setup(char *str) |
| 83 | { |
| 84 | softlockup_panic = simple_strtoul(str, NULL, 0); |
| 85 | |
| 86 | return 1; |
| 87 | } |
| 88 | __setup("softlockup_panic=", softlockup_panic_setup); |
| 89 | |
| 90 | static int __init nowatchdog_setup(char *str) |
| 91 | { |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 92 | watchdog_user_enabled = 0; |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 93 | return 1; |
| 94 | } |
| 95 | __setup("nowatchdog", nowatchdog_setup); |
| 96 | |
| 97 | /* deprecated */ |
| 98 | static int __init nosoftlockup_setup(char *str) |
| 99 | { |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 100 | watchdog_user_enabled = 0; |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 101 | return 1; |
| 102 | } |
| 103 | __setup("nosoftlockup", nosoftlockup_setup); |
| 104 | /* */ |
Aaron Tomlin | ed23587 | 2014-06-23 13:22:05 -0700 | [diff] [blame] | 105 | #ifdef CONFIG_SMP |
| 106 | static int __init softlockup_all_cpu_backtrace_setup(char *str) |
| 107 | { |
| 108 | sysctl_softlockup_all_cpu_backtrace = |
| 109 | !!simple_strtol(str, NULL, 0); |
| 110 | return 1; |
| 111 | } |
| 112 | __setup("softlockup_all_cpu_backtrace=", softlockup_all_cpu_backtrace_setup); |
| 113 | #endif |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 114 | |
Mandeep Singh Baines | 4eec42f | 2011-05-22 22:10:23 -0700 | [diff] [blame] | 115 | /* |
| 116 | * Hard-lockup warnings should be triggered after just a few seconds. Soft- |
| 117 | * lockups can have false positives under extreme conditions. So we generally |
| 118 | * want a higher threshold for soft lockups than for hard lockups. So we couple |
| 119 | * the thresholds with a factor: we make the soft threshold twice the amount of |
| 120 | * time the hard threshold is. |
| 121 | */ |
Ingo Molnar | 6e9101a | 2011-05-24 05:43:18 +0200 | [diff] [blame] | 122 | static int get_softlockup_thresh(void) |
Mandeep Singh Baines | 4eec42f | 2011-05-22 22:10:23 -0700 | [diff] [blame] | 123 | { |
| 124 | return watchdog_thresh * 2; |
| 125 | } |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 126 | |
| 127 | /* |
| 128 | * Returns seconds, approximately. We don't need nanosecond |
| 129 | * resolution, and we don't need to waste time with a big divide when |
| 130 | * 2^30ns == 1.074s. |
| 131 | */ |
Namhyung Kim | c06b4f1 | 2012-12-27 11:49:44 +0900 | [diff] [blame] | 132 | static unsigned long get_timestamp(void) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 133 | { |
Namhyung Kim | c06b4f1 | 2012-12-27 11:49:44 +0900 | [diff] [blame] | 134 | return local_clock() >> 30LL; /* 2^30 ~= 10^9 */ |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 135 | } |
| 136 | |
Chuansheng Liu | 0f34c40 | 2012-12-17 15:59:50 -0800 | [diff] [blame] | 137 | static void set_sample_period(void) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 138 | { |
| 139 | /* |
Mandeep Singh Baines | 586692a | 2011-05-22 22:10:22 -0700 | [diff] [blame] | 140 | * convert watchdog_thresh from seconds to ns |
Fernando Luis Vázquez Cao | 86f5e6a | 2012-02-09 17:42:22 -0500 | [diff] [blame] | 141 | * the divide by 5 is to give hrtimer several chances (two |
| 142 | * or three with the current relation between the soft |
| 143 | * and hard thresholds) to increment before the |
| 144 | * hardlockup detector generates a warning |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 145 | */ |
Chuansheng Liu | 0f34c40 | 2012-12-17 15:59:50 -0800 | [diff] [blame] | 146 | sample_period = get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 147 | } |
| 148 | |
| 149 | /* Commands for resetting the watchdog */ |
| 150 | static void __touch_watchdog(void) |
| 151 | { |
Namhyung Kim | c06b4f1 | 2012-12-27 11:49:44 +0900 | [diff] [blame] | 152 | __this_cpu_write(watchdog_touch_ts, get_timestamp()); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 153 | } |
| 154 | |
Don Zickus | 332fbdb | 2010-05-07 17:11:45 -0400 | [diff] [blame] | 155 | void touch_softlockup_watchdog(void) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 156 | { |
Andrew Morton | 7861144 | 2014-04-18 15:07:12 -0700 | [diff] [blame] | 157 | /* |
| 158 | * Preemption can be enabled. It doesn't matter which CPU's timestamp |
| 159 | * gets zeroed here, so use the raw_ operation. |
| 160 | */ |
| 161 | raw_cpu_write(watchdog_touch_ts, 0); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 162 | } |
Ingo Molnar | 0167c78 | 2010-05-13 08:53:33 +0200 | [diff] [blame] | 163 | EXPORT_SYMBOL(touch_softlockup_watchdog); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 164 | |
Don Zickus | 332fbdb | 2010-05-07 17:11:45 -0400 | [diff] [blame] | 165 | void touch_all_softlockup_watchdogs(void) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 166 | { |
| 167 | int cpu; |
| 168 | |
| 169 | /* |
| 170 | * this is done lockless |
| 171 | * do we care if a 0 races with a timestamp? |
| 172 | * all it means is the softlock check starts one cycle later |
| 173 | */ |
| 174 | for_each_online_cpu(cpu) |
| 175 | per_cpu(watchdog_touch_ts, cpu) = 0; |
| 176 | } |
| 177 | |
Don Zickus | cafcd80 | 2010-05-14 11:11:21 -0400 | [diff] [blame] | 178 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 179 | void touch_nmi_watchdog(void) |
| 180 | { |
Ben Zhang | 62572e2 | 2014-04-03 14:47:18 -0700 | [diff] [blame] | 181 | /* |
| 182 | * Using __raw here because some code paths have |
| 183 | * preemption enabled. If preemption is enabled |
| 184 | * then interrupts should be enabled too, in which |
| 185 | * case we shouldn't have to worry about the watchdog |
| 186 | * going off. |
| 187 | */ |
| 188 | __raw_get_cpu_var(watchdog_nmi_touch) = true; |
Don Zickus | 332fbdb | 2010-05-07 17:11:45 -0400 | [diff] [blame] | 189 | touch_softlockup_watchdog(); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 190 | } |
| 191 | EXPORT_SYMBOL(touch_nmi_watchdog); |
| 192 | |
Don Zickus | cafcd80 | 2010-05-14 11:11:21 -0400 | [diff] [blame] | 193 | #endif |
| 194 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 195 | void touch_softlockup_watchdog_sync(void) |
| 196 | { |
| 197 | __raw_get_cpu_var(softlockup_touch_sync) = true; |
| 198 | __raw_get_cpu_var(watchdog_touch_ts) = 0; |
| 199 | } |
| 200 | |
Frederic Weisbecker | 23637d4 | 2010-05-15 23:15:20 +0200 | [diff] [blame] | 201 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 202 | /* watchdog detector functions */ |
Don Zickus | 26e09c6 | 2010-05-17 18:06:04 -0400 | [diff] [blame] | 203 | static int is_hardlockup(void) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 204 | { |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 205 | unsigned long hrint = __this_cpu_read(hrtimer_interrupts); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 206 | |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 207 | if (__this_cpu_read(hrtimer_interrupts_saved) == hrint) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 208 | return 1; |
| 209 | |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 210 | __this_cpu_write(hrtimer_interrupts_saved, hrint); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 211 | return 0; |
| 212 | } |
| 213 | #endif |
| 214 | |
Don Zickus | 26e09c6 | 2010-05-17 18:06:04 -0400 | [diff] [blame] | 215 | static int is_softlockup(unsigned long touch_ts) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 216 | { |
Namhyung Kim | c06b4f1 | 2012-12-27 11:49:44 +0900 | [diff] [blame] | 217 | unsigned long now = get_timestamp(); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 218 | |
| 219 | /* Warn about unreasonable delays: */ |
Mandeep Singh Baines | 4eec42f | 2011-05-22 22:10:23 -0700 | [diff] [blame] | 220 | if (time_after(now, touch_ts + get_softlockup_thresh())) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 221 | return now - touch_ts; |
| 222 | |
| 223 | return 0; |
| 224 | } |
| 225 | |
Frederic Weisbecker | 23637d4 | 2010-05-15 23:15:20 +0200 | [diff] [blame] | 226 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
Cyrill Gorcunov | 1880c4a | 2011-06-23 16:49:18 +0400 | [diff] [blame] | 227 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 228 | static struct perf_event_attr wd_hw_attr = { |
| 229 | .type = PERF_TYPE_HARDWARE, |
| 230 | .config = PERF_COUNT_HW_CPU_CYCLES, |
| 231 | .size = sizeof(struct perf_event_attr), |
| 232 | .pinned = 1, |
| 233 | .disabled = 1, |
| 234 | }; |
| 235 | |
| 236 | /* Callback function for perf event subsystem */ |
Peter Zijlstra | a8b0ca1 | 2011-06-27 14:41:57 +0200 | [diff] [blame] | 237 | static void watchdog_overflow_callback(struct perf_event *event, |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 238 | struct perf_sample_data *data, |
| 239 | struct pt_regs *regs) |
| 240 | { |
Peter Zijlstra | c6db67c | 2010-08-20 11:49:15 +0200 | [diff] [blame] | 241 | /* Ensure the watchdog never gets throttled */ |
| 242 | event->hw.interrupts = 0; |
| 243 | |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 244 | if (__this_cpu_read(watchdog_nmi_touch) == true) { |
| 245 | __this_cpu_write(watchdog_nmi_touch, false); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 246 | return; |
| 247 | } |
| 248 | |
| 249 | /* check for a hardlockup |
| 250 | * This is done by making sure our timer interrupt |
| 251 | * is incrementing. The timer interrupt should have |
| 252 | * fired multiple times before we overflow'd. If it hasn't |
| 253 | * then this is a good indication the cpu is stuck |
| 254 | */ |
Don Zickus | 26e09c6 | 2010-05-17 18:06:04 -0400 | [diff] [blame] | 255 | if (is_hardlockup()) { |
| 256 | int this_cpu = smp_processor_id(); |
| 257 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 258 | /* only print hardlockups once */ |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 259 | if (__this_cpu_read(hard_watchdog_warn) == true) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 260 | return; |
| 261 | |
| 262 | if (hardlockup_panic) |
Fabian Frederick | 656c3b7 | 2014-08-06 16:04:03 -0700 | [diff] [blame] | 263 | panic("Watchdog detected hard LOCKUP on cpu %d", |
| 264 | this_cpu); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 265 | else |
Fabian Frederick | 656c3b7 | 2014-08-06 16:04:03 -0700 | [diff] [blame] | 266 | WARN(1, "Watchdog detected hard LOCKUP on cpu %d", |
| 267 | this_cpu); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 268 | |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 269 | __this_cpu_write(hard_watchdog_warn, true); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 270 | return; |
| 271 | } |
| 272 | |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 273 | __this_cpu_write(hard_watchdog_warn, false); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 274 | return; |
| 275 | } |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 276 | #endif /* CONFIG_HARDLOCKUP_DETECTOR */ |
| 277 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 278 | static void watchdog_interrupt_count(void) |
| 279 | { |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 280 | __this_cpu_inc(hrtimer_interrupts); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 281 | } |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 282 | |
| 283 | static int watchdog_nmi_enable(unsigned int cpu); |
| 284 | static void watchdog_nmi_disable(unsigned int cpu); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 285 | |
| 286 | /* watchdog kicker functions */ |
| 287 | static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) |
| 288 | { |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 289 | unsigned long touch_ts = __this_cpu_read(watchdog_touch_ts); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 290 | struct pt_regs *regs = get_irq_regs(); |
| 291 | int duration; |
Aaron Tomlin | ed23587 | 2014-06-23 13:22:05 -0700 | [diff] [blame] | 292 | int softlockup_all_cpu_backtrace = sysctl_softlockup_all_cpu_backtrace; |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 293 | |
| 294 | /* kick the hardlockup detector */ |
| 295 | watchdog_interrupt_count(); |
| 296 | |
| 297 | /* kick the softlockup detector */ |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 298 | wake_up_process(__this_cpu_read(softlockup_watchdog)); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 299 | |
| 300 | /* .. and repeat */ |
Chuansheng Liu | 0f34c40 | 2012-12-17 15:59:50 -0800 | [diff] [blame] | 301 | hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period)); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 302 | |
| 303 | if (touch_ts == 0) { |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 304 | if (unlikely(__this_cpu_read(softlockup_touch_sync))) { |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 305 | /* |
| 306 | * If the time stamp was touched atomically |
| 307 | * make sure the scheduler tick is up to date. |
| 308 | */ |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 309 | __this_cpu_write(softlockup_touch_sync, false); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 310 | sched_clock_tick(); |
| 311 | } |
Eric B Munson | 5d1c0f4 | 2012-03-10 14:37:28 -0500 | [diff] [blame] | 312 | |
| 313 | /* Clear the guest paused flag on watchdog reset */ |
| 314 | kvm_check_and_clear_guest_paused(); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 315 | __touch_watchdog(); |
| 316 | return HRTIMER_RESTART; |
| 317 | } |
| 318 | |
| 319 | /* check for a softlockup |
| 320 | * This is done by making sure a high priority task is |
| 321 | * being scheduled. The task touches the watchdog to |
| 322 | * indicate it is getting cpu time. If it hasn't then |
| 323 | * this is a good indication some task is hogging the cpu |
| 324 | */ |
Don Zickus | 26e09c6 | 2010-05-17 18:06:04 -0400 | [diff] [blame] | 325 | duration = is_softlockup(touch_ts); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 326 | if (unlikely(duration)) { |
Eric B Munson | 5d1c0f4 | 2012-03-10 14:37:28 -0500 | [diff] [blame] | 327 | /* |
| 328 | * If a virtual machine is stopped by the host it can look to |
| 329 | * the watchdog like a soft lockup, check to see if the host |
| 330 | * stopped the vm before we issue the warning |
| 331 | */ |
| 332 | if (kvm_check_and_clear_guest_paused()) |
| 333 | return HRTIMER_RESTART; |
| 334 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 335 | /* only warn once */ |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 336 | if (__this_cpu_read(soft_watchdog_warn) == true) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 337 | return HRTIMER_RESTART; |
| 338 | |
Aaron Tomlin | ed23587 | 2014-06-23 13:22:05 -0700 | [diff] [blame] | 339 | if (softlockup_all_cpu_backtrace) { |
| 340 | /* Prevent multiple soft-lockup reports if one cpu is already |
| 341 | * engaged in dumping cpu back traces |
| 342 | */ |
| 343 | if (test_and_set_bit(0, &soft_lockup_nmi_warn)) { |
| 344 | /* Someone else will report us. Let's give up */ |
| 345 | __this_cpu_write(soft_watchdog_warn, true); |
| 346 | return HRTIMER_RESTART; |
| 347 | } |
| 348 | } |
| 349 | |
Fabian Frederick | 656c3b7 | 2014-08-06 16:04:03 -0700 | [diff] [blame] | 350 | pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n", |
Don Zickus | 26e09c6 | 2010-05-17 18:06:04 -0400 | [diff] [blame] | 351 | smp_processor_id(), duration, |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 352 | current->comm, task_pid_nr(current)); |
| 353 | print_modules(); |
| 354 | print_irqtrace_events(current); |
| 355 | if (regs) |
| 356 | show_regs(regs); |
| 357 | else |
| 358 | dump_stack(); |
| 359 | |
Aaron Tomlin | ed23587 | 2014-06-23 13:22:05 -0700 | [diff] [blame] | 360 | if (softlockup_all_cpu_backtrace) { |
| 361 | /* Avoid generating two back traces for current |
| 362 | * given that one is already made above |
| 363 | */ |
| 364 | trigger_allbutself_cpu_backtrace(); |
| 365 | |
| 366 | clear_bit(0, &soft_lockup_nmi_warn); |
| 367 | /* Barrier to sync with other cpus */ |
| 368 | smp_mb__after_atomic(); |
| 369 | } |
| 370 | |
Josh Hunt | 69361ee | 2014-08-08 14:22:31 -0700 | [diff] [blame] | 371 | add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 372 | if (softlockup_panic) |
| 373 | panic("softlockup: hung tasks"); |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 374 | __this_cpu_write(soft_watchdog_warn, true); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 375 | } else |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 376 | __this_cpu_write(soft_watchdog_warn, false); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 377 | |
| 378 | return HRTIMER_RESTART; |
| 379 | } |
| 380 | |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 381 | static void watchdog_set_prio(unsigned int policy, unsigned int prio) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 382 | { |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 383 | struct sched_param param = { .sched_priority = prio }; |
| 384 | |
| 385 | sched_setscheduler(current, policy, ¶m); |
| 386 | } |
| 387 | |
| 388 | static void watchdog_enable(unsigned int cpu) |
| 389 | { |
Don Zickus | 26e09c6 | 2010-05-17 18:06:04 -0400 | [diff] [blame] | 390 | struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 391 | |
Bjørn Mork | 3935e895 | 2012-12-19 20:51:31 +0100 | [diff] [blame] | 392 | /* kick off the timer for the hardlockup detector */ |
| 393 | hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
| 394 | hrtimer->function = watchdog_timer_fn; |
| 395 | |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 396 | /* Enable the perf event */ |
| 397 | watchdog_nmi_enable(cpu); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 398 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 399 | /* done here because hrtimer_start can only pin to smp_processor_id() */ |
Chuansheng Liu | 0f34c40 | 2012-12-17 15:59:50 -0800 | [diff] [blame] | 400 | hrtimer_start(hrtimer, ns_to_ktime(sample_period), |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 401 | HRTIMER_MODE_REL_PINNED); |
| 402 | |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 403 | /* initialize timestamp */ |
| 404 | watchdog_set_prio(SCHED_FIFO, MAX_RT_PRIO - 1); |
| 405 | __touch_watchdog(); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 406 | } |
| 407 | |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 408 | static void watchdog_disable(unsigned int cpu) |
| 409 | { |
| 410 | struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); |
| 411 | |
| 412 | watchdog_set_prio(SCHED_NORMAL, 0); |
| 413 | hrtimer_cancel(hrtimer); |
| 414 | /* disable the perf event */ |
| 415 | watchdog_nmi_disable(cpu); |
| 416 | } |
| 417 | |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 418 | static void watchdog_cleanup(unsigned int cpu, bool online) |
| 419 | { |
| 420 | watchdog_disable(cpu); |
| 421 | } |
| 422 | |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 423 | static int watchdog_should_run(unsigned int cpu) |
| 424 | { |
| 425 | return __this_cpu_read(hrtimer_interrupts) != |
| 426 | __this_cpu_read(soft_lockup_hrtimer_cnt); |
| 427 | } |
| 428 | |
| 429 | /* |
| 430 | * The watchdog thread function - touches the timestamp. |
| 431 | * |
Chuansheng Liu | 0f34c40 | 2012-12-17 15:59:50 -0800 | [diff] [blame] | 432 | * It only runs once every sample_period seconds (4 seconds by |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 433 | * default) to reset the softlockup timestamp. If this gets delayed |
| 434 | * for more than 2*watchdog_thresh seconds then the debug-printout |
| 435 | * triggers in watchdog_timer_fn(). |
| 436 | */ |
| 437 | static void watchdog(unsigned int cpu) |
| 438 | { |
| 439 | __this_cpu_write(soft_lockup_hrtimer_cnt, |
| 440 | __this_cpu_read(hrtimer_interrupts)); |
| 441 | __touch_watchdog(); |
| 442 | } |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 443 | |
Frederic Weisbecker | 23637d4 | 2010-05-15 23:15:20 +0200 | [diff] [blame] | 444 | #ifdef CONFIG_HARDLOCKUP_DETECTOR |
Don Zickus | a702704 | 2012-06-13 09:35:48 -0400 | [diff] [blame] | 445 | /* |
| 446 | * People like the simple clean cpu node info on boot. |
| 447 | * Reduce the watchdog noise by only printing messages |
| 448 | * that are different from what cpu0 displayed. |
| 449 | */ |
| 450 | static unsigned long cpu0_err; |
| 451 | |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 452 | static int watchdog_nmi_enable(unsigned int cpu) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 453 | { |
| 454 | struct perf_event_attr *wd_attr; |
| 455 | struct perf_event *event = per_cpu(watchdog_ev, cpu); |
| 456 | |
| 457 | /* is it already setup and enabled? */ |
| 458 | if (event && event->state > PERF_EVENT_STATE_OFF) |
| 459 | goto out; |
| 460 | |
| 461 | /* it is setup but not enabled */ |
| 462 | if (event != NULL) |
| 463 | goto out_enable; |
| 464 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 465 | wd_attr = &wd_hw_attr; |
Mandeep Singh Baines | 4eec42f | 2011-05-22 22:10:23 -0700 | [diff] [blame] | 466 | wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh); |
Cyrill Gorcunov | 1880c4a | 2011-06-23 16:49:18 +0400 | [diff] [blame] | 467 | |
| 468 | /* Try to register using hardware perf events */ |
Avi Kivity | 4dc0da8 | 2011-06-29 18:42:35 +0300 | [diff] [blame] | 469 | event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL); |
Don Zickus | a702704 | 2012-06-13 09:35:48 -0400 | [diff] [blame] | 470 | |
| 471 | /* save cpu0 error for future comparision */ |
| 472 | if (cpu == 0 && IS_ERR(event)) |
| 473 | cpu0_err = PTR_ERR(event); |
| 474 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 475 | if (!IS_ERR(event)) { |
Don Zickus | a702704 | 2012-06-13 09:35:48 -0400 | [diff] [blame] | 476 | /* only print for cpu0 or different than cpu0 */ |
| 477 | if (cpu == 0 || cpu0_err) |
| 478 | pr_info("enabled on all CPUs, permanently consumes one hw-PMU counter.\n"); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 479 | goto out_save; |
| 480 | } |
| 481 | |
Don Zickus | a702704 | 2012-06-13 09:35:48 -0400 | [diff] [blame] | 482 | /* skip displaying the same error again */ |
| 483 | if (cpu > 0 && (PTR_ERR(event) == cpu0_err)) |
| 484 | return PTR_ERR(event); |
Don Zickus | 5651f7f | 2011-02-09 14:02:33 -0500 | [diff] [blame] | 485 | |
| 486 | /* vary the KERN level based on the returned errno */ |
| 487 | if (PTR_ERR(event) == -EOPNOTSUPP) |
Andrew Morton | 4501980 | 2012-03-23 15:01:55 -0700 | [diff] [blame] | 488 | pr_info("disabled (cpu%i): not supported (no LAPIC?)\n", cpu); |
Don Zickus | 5651f7f | 2011-02-09 14:02:33 -0500 | [diff] [blame] | 489 | else if (PTR_ERR(event) == -ENOENT) |
Fabian Frederick | 656c3b7 | 2014-08-06 16:04:03 -0700 | [diff] [blame] | 490 | pr_warn("disabled (cpu%i): hardware events not enabled\n", |
Andrew Morton | 4501980 | 2012-03-23 15:01:55 -0700 | [diff] [blame] | 491 | cpu); |
Don Zickus | 5651f7f | 2011-02-09 14:02:33 -0500 | [diff] [blame] | 492 | else |
Andrew Morton | 4501980 | 2012-03-23 15:01:55 -0700 | [diff] [blame] | 493 | pr_err("disabled (cpu%i): unable to create perf event: %ld\n", |
| 494 | cpu, PTR_ERR(event)); |
Akinobu Mita | eac2433 | 2010-08-31 23:00:08 -0400 | [diff] [blame] | 495 | return PTR_ERR(event); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 496 | |
| 497 | /* success path */ |
| 498 | out_save: |
| 499 | per_cpu(watchdog_ev, cpu) = event; |
| 500 | out_enable: |
| 501 | perf_event_enable(per_cpu(watchdog_ev, cpu)); |
| 502 | out: |
| 503 | return 0; |
| 504 | } |
| 505 | |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 506 | static void watchdog_nmi_disable(unsigned int cpu) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 507 | { |
| 508 | struct perf_event *event = per_cpu(watchdog_ev, cpu); |
| 509 | |
| 510 | if (event) { |
| 511 | perf_event_disable(event); |
| 512 | per_cpu(watchdog_ev, cpu) = NULL; |
| 513 | |
| 514 | /* should be in cleanup, but blocks oprofile */ |
| 515 | perf_event_release_kernel(event); |
| 516 | } |
| 517 | return; |
| 518 | } |
| 519 | #else |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 520 | static int watchdog_nmi_enable(unsigned int cpu) { return 0; } |
| 521 | static void watchdog_nmi_disable(unsigned int cpu) { return; } |
Frederic Weisbecker | 23637d4 | 2010-05-15 23:15:20 +0200 | [diff] [blame] | 522 | #endif /* CONFIG_HARDLOCKUP_DETECTOR */ |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 523 | |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 524 | static struct smp_hotplug_thread watchdog_threads = { |
| 525 | .store = &softlockup_watchdog, |
| 526 | .thread_should_run = watchdog_should_run, |
| 527 | .thread_fn = watchdog, |
| 528 | .thread_comm = "watchdog/%u", |
| 529 | .setup = watchdog_enable, |
| 530 | .cleanup = watchdog_cleanup, |
| 531 | .park = watchdog_disable, |
| 532 | .unpark = watchdog_enable, |
| 533 | }; |
| 534 | |
Michal Hocko | 9809b18 | 2013-09-24 15:27:30 -0700 | [diff] [blame] | 535 | static void restart_watchdog_hrtimer(void *info) |
| 536 | { |
| 537 | struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); |
| 538 | int ret; |
| 539 | |
| 540 | /* |
| 541 | * No need to cancel and restart hrtimer if it is currently executing |
| 542 | * because it will reprogram itself with the new period now. |
| 543 | * We should never see it unqueued here because we are running per-cpu |
| 544 | * with interrupts disabled. |
| 545 | */ |
| 546 | ret = hrtimer_try_to_cancel(hrtimer); |
| 547 | if (ret == 1) |
| 548 | hrtimer_start(hrtimer, ns_to_ktime(sample_period), |
| 549 | HRTIMER_MODE_REL_PINNED); |
| 550 | } |
| 551 | |
| 552 | static void update_timers(int cpu) |
| 553 | { |
Michal Hocko | 9809b18 | 2013-09-24 15:27:30 -0700 | [diff] [blame] | 554 | /* |
| 555 | * Make sure that perf event counter will adopt to a new |
| 556 | * sampling period. Updating the sampling period directly would |
| 557 | * be much nicer but we do not have an API for that now so |
| 558 | * let's use a big hammer. |
| 559 | * Hrtimer will adopt the new period on the next tick but this |
| 560 | * might be late already so we have to restart the timer as well. |
| 561 | */ |
| 562 | watchdog_nmi_disable(cpu); |
Frederic Weisbecker | e0a23b0 | 2014-02-24 16:40:00 +0100 | [diff] [blame] | 563 | smp_call_function_single(cpu, restart_watchdog_hrtimer, NULL, 1); |
Michal Hocko | 9809b18 | 2013-09-24 15:27:30 -0700 | [diff] [blame] | 564 | watchdog_nmi_enable(cpu); |
| 565 | } |
| 566 | |
| 567 | static void update_timers_all_cpus(void) |
| 568 | { |
| 569 | int cpu; |
| 570 | |
| 571 | get_online_cpus(); |
Michal Hocko | 9809b18 | 2013-09-24 15:27:30 -0700 | [diff] [blame] | 572 | for_each_online_cpu(cpu) |
| 573 | update_timers(cpu); |
Michal Hocko | 9809b18 | 2013-09-24 15:27:30 -0700 | [diff] [blame] | 574 | put_online_cpus(); |
| 575 | } |
| 576 | |
| 577 | static int watchdog_enable_all_cpus(bool sample_period_changed) |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 578 | { |
| 579 | int err = 0; |
| 580 | |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 581 | if (!watchdog_running) { |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 582 | err = smpboot_register_percpu_thread(&watchdog_threads); |
| 583 | if (err) |
| 584 | pr_err("Failed to create watchdog threads, disabled\n"); |
| 585 | else |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 586 | watchdog_running = 1; |
Michal Hocko | 9809b18 | 2013-09-24 15:27:30 -0700 | [diff] [blame] | 587 | } else if (sample_period_changed) { |
| 588 | update_timers_all_cpus(); |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 589 | } |
| 590 | |
| 591 | return err; |
| 592 | } |
| 593 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 594 | /* prepare/enable/disable routines */ |
Vasily Averin | 4ff8195 | 2011-10-31 17:11:18 -0700 | [diff] [blame] | 595 | /* sysctl functions */ |
| 596 | #ifdef CONFIG_SYSCTL |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 597 | static void watchdog_disable_all_cpus(void) |
| 598 | { |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 599 | if (watchdog_running) { |
| 600 | watchdog_running = 0; |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 601 | smpboot_unregister_percpu_thread(&watchdog_threads); |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 602 | } |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 603 | } |
| 604 | |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 605 | /* |
Mandeep Singh Baines | 586692a | 2011-05-22 22:10:22 -0700 | [diff] [blame] | 606 | * proc handler for /proc/sys/kernel/nmi_watchdog,watchdog_thresh |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 607 | */ |
| 608 | |
Mandeep Singh Baines | 586692a | 2011-05-22 22:10:22 -0700 | [diff] [blame] | 609 | int proc_dowatchdog(struct ctl_table *table, int write, |
| 610 | void __user *buffer, size_t *lenp, loff_t *ppos) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 611 | { |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 612 | int err, old_thresh, old_enabled; |
Michal Hocko | 359e6fa | 2013-09-24 15:27:29 -0700 | [diff] [blame] | 613 | static DEFINE_MUTEX(watchdog_proc_mutex); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 614 | |
Michal Hocko | 359e6fa | 2013-09-24 15:27:29 -0700 | [diff] [blame] | 615 | mutex_lock(&watchdog_proc_mutex); |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 616 | old_thresh = ACCESS_ONCE(watchdog_thresh); |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 617 | old_enabled = ACCESS_ONCE(watchdog_user_enabled); |
Thomas Gleixner | bcd951c | 2012-07-16 10:42:38 +0000 | [diff] [blame] | 618 | |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 619 | err = proc_dointvec_minmax(table, write, buffer, lenp, ppos); |
| 620 | if (err || !write) |
Michal Hocko | 359e6fa | 2013-09-24 15:27:29 -0700 | [diff] [blame] | 621 | goto out; |
Mandeep Singh Baines | e04ab2b | 2011-05-22 22:10:21 -0700 | [diff] [blame] | 622 | |
Chuansheng Liu | 0f34c40 | 2012-12-17 15:59:50 -0800 | [diff] [blame] | 623 | set_sample_period(); |
anish kumar | b66a235 | 2013-03-12 14:44:08 -0400 | [diff] [blame] | 624 | /* |
| 625 | * Watchdog threads shouldn't be enabled if they are |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 626 | * disabled. The 'watchdog_running' variable check in |
anish kumar | b66a235 | 2013-03-12 14:44:08 -0400 | [diff] [blame] | 627 | * watchdog_*_all_cpus() function takes care of this. |
| 628 | */ |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 629 | if (watchdog_user_enabled && watchdog_thresh) |
Michal Hocko | 9809b18 | 2013-09-24 15:27:30 -0700 | [diff] [blame] | 630 | err = watchdog_enable_all_cpus(old_thresh != watchdog_thresh); |
Mandeep Singh Baines | e04ab2b | 2011-05-22 22:10:21 -0700 | [diff] [blame] | 631 | else |
| 632 | watchdog_disable_all_cpus(); |
| 633 | |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 634 | /* Restore old values on failure */ |
| 635 | if (err) { |
| 636 | watchdog_thresh = old_thresh; |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 637 | watchdog_user_enabled = old_enabled; |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 638 | } |
Michal Hocko | 359e6fa | 2013-09-24 15:27:29 -0700 | [diff] [blame] | 639 | out: |
| 640 | mutex_unlock(&watchdog_proc_mutex); |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 641 | return err; |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 642 | } |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 643 | #endif /* CONFIG_SYSCTL */ |
| 644 | |
Peter Zijlstra | 004417a | 2010-11-25 18:38:29 +0100 | [diff] [blame] | 645 | void __init lockup_detector_init(void) |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 646 | { |
Chuansheng Liu | 0f34c40 | 2012-12-17 15:59:50 -0800 | [diff] [blame] | 647 | set_sample_period(); |
Frederic Weisbecker | b8900bc | 2013-06-06 15:42:53 +0200 | [diff] [blame] | 648 | |
Frederic Weisbecker | 3c00ea8 | 2013-05-19 20:45:15 +0200 | [diff] [blame] | 649 | if (watchdog_user_enabled) |
Michal Hocko | 9809b18 | 2013-09-24 15:27:30 -0700 | [diff] [blame] | 650 | watchdog_enable_all_cpus(false); |
Don Zickus | 58687ac | 2010-05-07 17:11:44 -0400 | [diff] [blame] | 651 | } |