Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/fork.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * 'fork.c' contains the help-routines for the 'fork' system call |
| 9 | * (see also entry.S and others). |
| 10 | * Fork is rather simple, once you get the hang of it, but the memory |
| 11 | * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' |
| 12 | */ |
| 13 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | #include <linux/slab.h> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/unistd.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/module.h> |
| 18 | #include <linux/vmalloc.h> |
| 19 | #include <linux/completion.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/personality.h> |
| 21 | #include <linux/mempolicy.h> |
| 22 | #include <linux/sem.h> |
| 23 | #include <linux/file.h> |
Al Viro | 9f3acc3 | 2008-04-24 07:44:08 -0400 | [diff] [blame] | 24 | #include <linux/fdtable.h> |
Jens Axboe | da9cbc8 | 2008-06-30 20:42:08 +0200 | [diff] [blame] | 25 | #include <linux/iocontext.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <linux/key.h> |
| 27 | #include <linux/binfmts.h> |
| 28 | #include <linux/mman.h> |
Andrea Arcangeli | cddb8a5 | 2008-07-28 15:46:29 -0700 | [diff] [blame] | 29 | #include <linux/mmu_notifier.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | #include <linux/fs.h> |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 31 | #include <linux/nsproxy.h> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 32 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | #include <linux/cpu.h> |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 34 | #include <linux/cgroup.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <linux/security.h> |
Mel Gorman | a1e7877 | 2008-07-23 21:27:23 -0700 | [diff] [blame] | 36 | #include <linux/hugetlb.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | #include <linux/swap.h> |
| 38 | #include <linux/syscalls.h> |
| 39 | #include <linux/jiffies.h> |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 40 | #include <linux/tracehook.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | #include <linux/futex.h> |
Linus Torvalds | 8141c7f | 2008-11-15 10:20:36 -0800 | [diff] [blame] | 42 | #include <linux/compat.h> |
Andrew Morton | 7c3ab73 | 2006-12-10 02:19:19 -0800 | [diff] [blame] | 43 | #include <linux/task_io_accounting_ops.h> |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 44 | #include <linux/rcupdate.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | #include <linux/ptrace.h> |
| 46 | #include <linux/mount.h> |
| 47 | #include <linux/audit.h> |
Pavel Emelianov | 78fb746 | 2008-02-07 00:13:51 -0800 | [diff] [blame] | 48 | #include <linux/memcontrol.h> |
Frederic Weisbecker | f201ae2 | 2008-11-23 06:22:56 +0100 | [diff] [blame] | 49 | #include <linux/ftrace.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | #include <linux/profile.h> |
| 51 | #include <linux/rmap.h> |
Hugh Dickins | f8af4da | 2009-09-21 17:01:57 -0700 | [diff] [blame] | 52 | #include <linux/ksm.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | #include <linux/acct.h> |
Jay Lan | 8f0ab51 | 2006-09-30 23:28:59 -0700 | [diff] [blame] | 54 | #include <linux/tsacct_kern.h> |
Matt Helsley | 9f46080 | 2005-11-07 00:59:16 -0800 | [diff] [blame] | 55 | #include <linux/cn_proc.h> |
Rafael J. Wysocki | ba96a0c | 2007-05-23 13:57:25 -0700 | [diff] [blame] | 56 | #include <linux/freezer.h> |
Shailabh Nagar | ca74e92 | 2006-07-14 00:24:36 -0700 | [diff] [blame] | 57 | #include <linux/delayacct.h> |
Shailabh Nagar | ad4ecbc | 2006-07-14 00:24:44 -0700 | [diff] [blame] | 58 | #include <linux/taskstats_kern.h> |
Arjan van de Ven | 0a42540 | 2006-09-26 10:52:38 +0200 | [diff] [blame] | 59 | #include <linux/random.h> |
Miloslav Trmac | 522ed77 | 2007-07-15 23:40:56 -0700 | [diff] [blame] | 60 | #include <linux/tty.h> |
Pavel Emelyanov | 6f4e643 | 2007-10-18 23:40:11 -0700 | [diff] [blame] | 61 | #include <linux/proc_fs.h> |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 62 | #include <linux/blkdev.h> |
Al Viro | 5ad4e53 | 2009-03-29 19:50:06 -0400 | [diff] [blame] | 63 | #include <linux/fs_struct.h> |
Eric Sandeen | 7c9f886 | 2008-04-22 16:38:23 -0500 | [diff] [blame] | 64 | #include <linux/magic.h> |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 65 | #include <linux/perf_event.h> |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 66 | #include <linux/posix-timers.h> |
Avi Kivity | 8e7cac7 | 2009-11-29 16:34:48 +0200 | [diff] [blame] | 67 | #include <linux/user-return-notifier.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | |
| 69 | #include <asm/pgtable.h> |
| 70 | #include <asm/pgalloc.h> |
| 71 | #include <asm/uaccess.h> |
| 72 | #include <asm/mmu_context.h> |
| 73 | #include <asm/cacheflush.h> |
| 74 | #include <asm/tlbflush.h> |
| 75 | |
Steven Rostedt | ad8d75f | 2009-04-14 19:39:12 -0400 | [diff] [blame] | 76 | #include <trace/events/sched.h> |
| 77 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | /* |
| 79 | * Protected counters by write_lock_irq(&tasklist_lock) |
| 80 | */ |
| 81 | unsigned long total_forks; /* Handle normal Linux uptimes. */ |
| 82 | int nr_threads; /* The idle threads do not count.. */ |
| 83 | |
| 84 | int max_threads; /* tunable limit on nr_threads */ |
| 85 | |
| 86 | DEFINE_PER_CPU(unsigned long, process_counts) = 0; |
| 87 | |
Christoph Hellwig | c59923a | 2006-07-10 04:45:40 -0700 | [diff] [blame] | 88 | __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ |
Paul E. McKenney | db1466b | 2010-03-03 07:46:56 -0800 | [diff] [blame] | 89 | |
| 90 | #ifdef CONFIG_PROVE_RCU |
| 91 | int lockdep_tasklist_lock_is_held(void) |
| 92 | { |
| 93 | return lockdep_is_held(&tasklist_lock); |
| 94 | } |
| 95 | EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); |
| 96 | #endif /* #ifdef CONFIG_PROVE_RCU */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | |
| 98 | int nr_processes(void) |
| 99 | { |
| 100 | int cpu; |
| 101 | int total = 0; |
| 102 | |
Ian Campbell | 1d51075 | 2009-11-03 10:11:14 +0000 | [diff] [blame] | 103 | for_each_possible_cpu(cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | total += per_cpu(process_counts, cpu); |
| 105 | |
| 106 | return total; |
| 107 | } |
| 108 | |
| 109 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR |
| 110 | # define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) |
| 111 | # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 112 | static struct kmem_cache *task_struct_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | #endif |
| 114 | |
FUJITA Tomonori | b69c49b | 2008-07-25 01:45:40 -0700 | [diff] [blame] | 115 | #ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR |
| 116 | static inline struct thread_info *alloc_thread_info(struct task_struct *tsk) |
| 117 | { |
| 118 | #ifdef CONFIG_DEBUG_STACK_USAGE |
| 119 | gfp_t mask = GFP_KERNEL | __GFP_ZERO; |
| 120 | #else |
| 121 | gfp_t mask = GFP_KERNEL; |
| 122 | #endif |
| 123 | return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER); |
| 124 | } |
| 125 | |
| 126 | static inline void free_thread_info(struct thread_info *ti) |
| 127 | { |
| 128 | free_pages((unsigned long)ti, THREAD_SIZE_ORDER); |
| 129 | } |
| 130 | #endif |
| 131 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | /* SLAB cache for signal_struct structures (tsk->signal) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 133 | static struct kmem_cache *signal_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | |
| 135 | /* SLAB cache for sighand_struct structures (tsk->sighand) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 136 | struct kmem_cache *sighand_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | |
| 138 | /* SLAB cache for files_struct structures (tsk->files) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 139 | struct kmem_cache *files_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | |
| 141 | /* SLAB cache for fs_struct structures (tsk->fs) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 142 | struct kmem_cache *fs_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | |
| 144 | /* SLAB cache for vm_area_struct structures */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 145 | struct kmem_cache *vm_area_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | |
| 147 | /* SLAB cache for mm_struct structures (tsk->mm) */ |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 148 | static struct kmem_cache *mm_cachep; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | |
KOSAKI Motohiro | c6a7f57 | 2009-09-21 17:01:32 -0700 | [diff] [blame] | 150 | static void account_kernel_stack(struct thread_info *ti, int account) |
| 151 | { |
| 152 | struct zone *zone = page_zone(virt_to_page(ti)); |
| 153 | |
| 154 | mod_zone_page_state(zone, NR_KERNEL_STACK, account); |
| 155 | } |
| 156 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | void free_task(struct task_struct *tsk) |
| 158 | { |
Peter Zijlstra | 3e26c14 | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 159 | prop_local_destroy_single(&tsk->dirties); |
KOSAKI Motohiro | c6a7f57 | 2009-09-21 17:01:32 -0700 | [diff] [blame] | 160 | account_kernel_stack(tsk->stack, -1); |
Roman Zippel | f7e4217 | 2007-05-09 02:35:17 -0700 | [diff] [blame] | 161 | free_thread_info(tsk->stack); |
Ingo Molnar | 23f78d4a | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 162 | rt_mutex_debug_task_free(tsk); |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 163 | ftrace_graph_exit_task(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 164 | free_task_struct(tsk); |
| 165 | } |
| 166 | EXPORT_SYMBOL(free_task); |
| 167 | |
Andrew Morton | 158d9eb | 2006-03-31 02:31:34 -0800 | [diff] [blame] | 168 | void __put_task_struct(struct task_struct *tsk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | { |
Eugene Teo | 270f722 | 2007-10-18 23:40:38 -0700 | [diff] [blame] | 170 | WARN_ON(!tsk->exit_state); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | WARN_ON(atomic_read(&tsk->usage)); |
| 172 | WARN_ON(tsk == current); |
| 173 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 174 | exit_creds(tsk); |
Shailabh Nagar | 35df17c | 2006-08-31 21:27:38 -0700 | [diff] [blame] | 175 | delayacct_tsk_free(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | |
| 177 | if (!profile_handoff_task(tsk)) |
| 178 | free_task(tsk); |
| 179 | } |
| 180 | |
Suresh Siddha | 2adee9b | 2008-04-16 10:25:35 +0200 | [diff] [blame] | 181 | /* |
| 182 | * macro override instead of weak attribute alias, to workaround |
| 183 | * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions. |
| 184 | */ |
| 185 | #ifndef arch_task_cache_init |
| 186 | #define arch_task_cache_init() |
| 187 | #endif |
Suresh Siddha | 61c4628 | 2008-03-10 15:28:04 -0700 | [diff] [blame] | 188 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | void __init fork_init(unsigned long mempages) |
| 190 | { |
| 191 | #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR |
| 192 | #ifndef ARCH_MIN_TASKALIGN |
| 193 | #define ARCH_MIN_TASKALIGN L1_CACHE_BYTES |
| 194 | #endif |
| 195 | /* create a slab on which task_structs can be allocated */ |
| 196 | task_struct_cachep = |
| 197 | kmem_cache_create("task_struct", sizeof(struct task_struct), |
Vegard Nossum | 2dff440 | 2008-05-31 15:56:17 +0200 | [diff] [blame] | 198 | ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | #endif |
| 200 | |
Suresh Siddha | 61c4628 | 2008-03-10 15:28:04 -0700 | [diff] [blame] | 201 | /* do the arch specific task caches init */ |
| 202 | arch_task_cache_init(); |
| 203 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | /* |
| 205 | * The default maximum number of threads is set to a safe |
| 206 | * value: the thread structures can take up at most half |
| 207 | * of memory. |
| 208 | */ |
| 209 | max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE); |
| 210 | |
| 211 | /* |
| 212 | * we need to allow at least 20 threads to boot a system |
| 213 | */ |
| 214 | if(max_threads < 20) |
| 215 | max_threads = 20; |
| 216 | |
| 217 | init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2; |
| 218 | init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2; |
| 219 | init_task.signal->rlim[RLIMIT_SIGPENDING] = |
| 220 | init_task.signal->rlim[RLIMIT_NPROC]; |
| 221 | } |
| 222 | |
Suresh Siddha | 61c4628 | 2008-03-10 15:28:04 -0700 | [diff] [blame] | 223 | int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, |
| 224 | struct task_struct *src) |
| 225 | { |
| 226 | *dst = *src; |
| 227 | return 0; |
| 228 | } |
| 229 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | static struct task_struct *dup_task_struct(struct task_struct *orig) |
| 231 | { |
| 232 | struct task_struct *tsk; |
| 233 | struct thread_info *ti; |
Eric Sandeen | 7c9f886 | 2008-04-22 16:38:23 -0500 | [diff] [blame] | 234 | unsigned long *stackend; |
| 235 | |
Peter Zijlstra | 3e26c14 | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 236 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | |
| 238 | prepare_to_copy(orig); |
| 239 | |
| 240 | tsk = alloc_task_struct(); |
| 241 | if (!tsk) |
| 242 | return NULL; |
| 243 | |
| 244 | ti = alloc_thread_info(tsk); |
| 245 | if (!ti) { |
| 246 | free_task_struct(tsk); |
| 247 | return NULL; |
| 248 | } |
| 249 | |
Suresh Siddha | 61c4628 | 2008-03-10 15:28:04 -0700 | [diff] [blame] | 250 | err = arch_dup_task_struct(tsk, orig); |
| 251 | if (err) |
| 252 | goto out; |
| 253 | |
Roman Zippel | f7e4217 | 2007-05-09 02:35:17 -0700 | [diff] [blame] | 254 | tsk->stack = ti; |
Peter Zijlstra | 3e26c14 | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 255 | |
| 256 | err = prop_local_init_single(&tsk->dirties); |
Suresh Siddha | 61c4628 | 2008-03-10 15:28:04 -0700 | [diff] [blame] | 257 | if (err) |
| 258 | goto out; |
Peter Zijlstra | 3e26c14 | 2007-10-16 23:25:50 -0700 | [diff] [blame] | 259 | |
Al Viro | 10ebffd | 2005-11-13 16:06:56 -0800 | [diff] [blame] | 260 | setup_thread_stack(tsk, orig); |
Avi Kivity | 8e7cac7 | 2009-11-29 16:34:48 +0200 | [diff] [blame] | 261 | clear_user_return_notifier(tsk); |
Eric Sandeen | 7c9f886 | 2008-04-22 16:38:23 -0500 | [diff] [blame] | 262 | stackend = end_of_stack(tsk); |
| 263 | *stackend = STACK_END_MAGIC; /* for overflow detection */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | |
Arjan van de Ven | 0a42540 | 2006-09-26 10:52:38 +0200 | [diff] [blame] | 265 | #ifdef CONFIG_CC_STACKPROTECTOR |
| 266 | tsk->stack_canary = get_random_int(); |
| 267 | #endif |
| 268 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | /* One for us, one for whoever does the "release_task()" (usually parent) */ |
| 270 | atomic_set(&tsk->usage,2); |
Giancarlo Formicuccia | 4b5d37a | 2005-09-09 13:01:22 -0700 | [diff] [blame] | 271 | atomic_set(&tsk->fs_excl, 0); |
Alexey Dobriyan | 6c5c934 | 2006-09-29 01:59:40 -0700 | [diff] [blame] | 272 | #ifdef CONFIG_BLK_DEV_IO_TRACE |
Jens Axboe | 2056a78 | 2006-03-23 20:00:26 +0100 | [diff] [blame] | 273 | tsk->btrace_seq = 0; |
Alexey Dobriyan | 6c5c934 | 2006-09-29 01:59:40 -0700 | [diff] [blame] | 274 | #endif |
Jens Axboe | a0aa7f6 | 2006-04-20 13:05:33 +0200 | [diff] [blame] | 275 | tsk->splice_pipe = NULL; |
KOSAKI Motohiro | c6a7f57 | 2009-09-21 17:01:32 -0700 | [diff] [blame] | 276 | |
| 277 | account_kernel_stack(ti, 1); |
| 278 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | return tsk; |
Suresh Siddha | 61c4628 | 2008-03-10 15:28:04 -0700 | [diff] [blame] | 280 | |
| 281 | out: |
| 282 | free_thread_info(ti); |
| 283 | free_task_struct(tsk); |
| 284 | return NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 285 | } |
| 286 | |
| 287 | #ifdef CONFIG_MMU |
Alexey Dobriyan | a39bc51 | 2007-10-18 23:41:10 -0700 | [diff] [blame] | 288 | static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 289 | { |
Hugh Dickins | fd3e42f | 2005-10-29 18:16:06 -0700 | [diff] [blame] | 290 | struct vm_area_struct *mpnt, *tmp, **pprev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | struct rb_node **rb_link, *rb_parent; |
| 292 | int retval; |
| 293 | unsigned long charge; |
| 294 | struct mempolicy *pol; |
| 295 | |
| 296 | down_write(&oldmm->mmap_sem); |
Ralf Baechle | ec8c044 | 2006-12-12 17:14:57 +0000 | [diff] [blame] | 297 | flush_cache_dup_mm(oldmm); |
Ingo Molnar | ad33945 | 2006-07-03 00:25:15 -0700 | [diff] [blame] | 298 | /* |
| 299 | * Not linked in yet - no deadlock potential: |
| 300 | */ |
| 301 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); |
Hugh Dickins | 7ee7823 | 2005-10-29 18:16:08 -0700 | [diff] [blame] | 302 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 303 | mm->locked_vm = 0; |
| 304 | mm->mmap = NULL; |
| 305 | mm->mmap_cache = NULL; |
| 306 | mm->free_area_cache = oldmm->mmap_base; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 307 | mm->cached_hole_size = ~0UL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 308 | mm->map_count = 0; |
Rusty Russell | 9489424 | 2009-03-30 22:05:12 -0600 | [diff] [blame] | 309 | cpumask_clear(mm_cpumask(mm)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | mm->mm_rb = RB_ROOT; |
| 311 | rb_link = &mm->mm_rb.rb_node; |
| 312 | rb_parent = NULL; |
| 313 | pprev = &mm->mmap; |
Hugh Dickins | f8af4da | 2009-09-21 17:01:57 -0700 | [diff] [blame] | 314 | retval = ksm_fork(mm, oldmm); |
| 315 | if (retval) |
| 316 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | |
Hugh Dickins | fd3e42f | 2005-10-29 18:16:06 -0700 | [diff] [blame] | 318 | for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 319 | struct file *file; |
| 320 | |
| 321 | if (mpnt->vm_flags & VM_DONTCOPY) { |
Hugh Dickins | 3b6bfcd | 2005-07-12 13:58:09 -0700 | [diff] [blame] | 322 | long pages = vma_pages(mpnt); |
| 323 | mm->total_vm -= pages; |
Hugh Dickins | ab50b8e | 2005-10-29 18:15:56 -0700 | [diff] [blame] | 324 | vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file, |
Hugh Dickins | 3b6bfcd | 2005-07-12 13:58:09 -0700 | [diff] [blame] | 325 | -pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 326 | continue; |
| 327 | } |
| 328 | charge = 0; |
| 329 | if (mpnt->vm_flags & VM_ACCOUNT) { |
| 330 | unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT; |
| 331 | if (security_vm_enough_memory(len)) |
| 332 | goto fail_nomem; |
| 333 | charge = len; |
| 334 | } |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 335 | tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | if (!tmp) |
| 337 | goto fail_nomem; |
| 338 | *tmp = *mpnt; |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 339 | INIT_LIST_HEAD(&tmp->anon_vma_chain); |
Lee Schermerhorn | 846a16b | 2008-04-28 02:13:09 -0700 | [diff] [blame] | 340 | pol = mpol_dup(vma_policy(mpnt)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | retval = PTR_ERR(pol); |
| 342 | if (IS_ERR(pol)) |
| 343 | goto fail_nomem_policy; |
| 344 | vma_set_policy(tmp, pol); |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 345 | if (anon_vma_fork(tmp, mpnt)) |
| 346 | goto fail_nomem_anon_vma_fork; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | tmp->vm_flags &= ~VM_LOCKED; |
| 348 | tmp->vm_mm = mm; |
| 349 | tmp->vm_next = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | file = tmp->vm_file; |
| 351 | if (file) { |
Josef "Jeff" Sipek | f3a43f3 | 2006-12-08 02:36:43 -0800 | [diff] [blame] | 352 | struct inode *inode = file->f_path.dentry->d_inode; |
Hugh Dickins | b88ed20 | 2008-12-10 20:48:52 +0000 | [diff] [blame] | 353 | struct address_space *mapping = file->f_mapping; |
| 354 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 355 | get_file(file); |
| 356 | if (tmp->vm_flags & VM_DENYWRITE) |
| 357 | atomic_dec(&inode->i_writecount); |
Hugh Dickins | b88ed20 | 2008-12-10 20:48:52 +0000 | [diff] [blame] | 358 | spin_lock(&mapping->i_mmap_lock); |
| 359 | if (tmp->vm_flags & VM_SHARED) |
| 360 | mapping->i_mmap_writable++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 361 | tmp->vm_truncate_count = mpnt->vm_truncate_count; |
Hugh Dickins | b88ed20 | 2008-12-10 20:48:52 +0000 | [diff] [blame] | 362 | flush_dcache_mmap_lock(mapping); |
| 363 | /* insert tmp into the share list, just after mpnt */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 364 | vma_prio_tree_add(tmp, mpnt); |
Hugh Dickins | b88ed20 | 2008-12-10 20:48:52 +0000 | [diff] [blame] | 365 | flush_dcache_mmap_unlock(mapping); |
| 366 | spin_unlock(&mapping->i_mmap_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 367 | } |
| 368 | |
| 369 | /* |
Mel Gorman | a1e7877 | 2008-07-23 21:27:23 -0700 | [diff] [blame] | 370 | * Clear hugetlb-related page reserves for children. This only |
| 371 | * affects MAP_PRIVATE mappings. Faults generated by the child |
| 372 | * are not guaranteed to succeed, even if read-only |
| 373 | */ |
| 374 | if (is_vm_hugetlb_page(tmp)) |
| 375 | reset_vma_resv_huge_pages(tmp); |
| 376 | |
| 377 | /* |
Hugh Dickins | 7ee7823 | 2005-10-29 18:16:08 -0700 | [diff] [blame] | 378 | * Link in the new vma and copy the page table entries. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 380 | *pprev = tmp; |
| 381 | pprev = &tmp->vm_next; |
| 382 | |
| 383 | __vma_link_rb(mm, tmp, rb_link, rb_parent); |
| 384 | rb_link = &tmp->vm_rb.rb_right; |
| 385 | rb_parent = &tmp->vm_rb; |
| 386 | |
| 387 | mm->map_count++; |
Hugh Dickins | 0b0db14 | 2005-11-21 21:32:20 -0800 | [diff] [blame] | 388 | retval = copy_page_range(mm, oldmm, mpnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 389 | |
| 390 | if (tmp->vm_ops && tmp->vm_ops->open) |
| 391 | tmp->vm_ops->open(tmp); |
| 392 | |
| 393 | if (retval) |
| 394 | goto out; |
| 395 | } |
Jeremy Fitzhardinge | d6dd61c | 2007-05-02 19:27:14 +0200 | [diff] [blame] | 396 | /* a new mm has just been created */ |
| 397 | arch_dup_mmap(oldmm, mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 398 | retval = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 | out: |
Hugh Dickins | 7ee7823 | 2005-10-29 18:16:08 -0700 | [diff] [blame] | 400 | up_write(&mm->mmap_sem); |
Hugh Dickins | fd3e42f | 2005-10-29 18:16:06 -0700 | [diff] [blame] | 401 | flush_tlb_mm(oldmm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 402 | up_write(&oldmm->mmap_sem); |
| 403 | return retval; |
Rik van Riel | 5beb493 | 2010-03-05 13:42:07 -0800 | [diff] [blame] | 404 | fail_nomem_anon_vma_fork: |
| 405 | mpol_put(pol); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | fail_nomem_policy: |
| 407 | kmem_cache_free(vm_area_cachep, tmp); |
| 408 | fail_nomem: |
| 409 | retval = -ENOMEM; |
| 410 | vm_unacct_memory(charge); |
| 411 | goto out; |
| 412 | } |
| 413 | |
| 414 | static inline int mm_alloc_pgd(struct mm_struct * mm) |
| 415 | { |
| 416 | mm->pgd = pgd_alloc(mm); |
| 417 | if (unlikely(!mm->pgd)) |
| 418 | return -ENOMEM; |
| 419 | return 0; |
| 420 | } |
| 421 | |
| 422 | static inline void mm_free_pgd(struct mm_struct * mm) |
| 423 | { |
Benjamin Herrenschmidt | 5e54197 | 2008-02-04 22:29:14 -0800 | [diff] [blame] | 424 | pgd_free(mm, mm->pgd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 425 | } |
| 426 | #else |
| 427 | #define dup_mmap(mm, oldmm) (0) |
| 428 | #define mm_alloc_pgd(mm) (0) |
| 429 | #define mm_free_pgd(mm) |
| 430 | #endif /* CONFIG_MMU */ |
| 431 | |
Daniel Walker | 23ff444 | 2007-10-18 03:06:07 -0700 | [diff] [blame] | 432 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 434 | #define allocate_mm() (kmem_cache_alloc(mm_cachep, GFP_KERNEL)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm))) |
| 436 | |
Hidehiro Kawai | 4cb0e11 | 2009-01-06 14:42:47 -0800 | [diff] [blame] | 437 | static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT; |
| 438 | |
| 439 | static int __init coredump_filter_setup(char *s) |
| 440 | { |
| 441 | default_dump_filter = |
| 442 | (simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) & |
| 443 | MMF_DUMP_FILTER_MASK; |
| 444 | return 1; |
| 445 | } |
| 446 | |
| 447 | __setup("coredump_filter=", coredump_filter_setup); |
| 448 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | #include <linux/init_task.h> |
| 450 | |
Alexey Dobriyan | 858f099 | 2009-09-23 15:57:32 -0700 | [diff] [blame] | 451 | static void mm_init_aio(struct mm_struct *mm) |
| 452 | { |
| 453 | #ifdef CONFIG_AIO |
| 454 | spin_lock_init(&mm->ioctx_lock); |
| 455 | INIT_HLIST_HEAD(&mm->ioctx_list); |
| 456 | #endif |
| 457 | } |
| 458 | |
Pavel Emelianov | 78fb746 | 2008-02-07 00:13:51 -0800 | [diff] [blame] | 459 | static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | { |
| 461 | atomic_set(&mm->mm_users, 1); |
| 462 | atomic_set(&mm->mm_count, 1); |
| 463 | init_rwsem(&mm->mmap_sem); |
| 464 | INIT_LIST_HEAD(&mm->mmlist); |
Hugh Dickins | f8af4da | 2009-09-21 17:01:57 -0700 | [diff] [blame] | 465 | mm->flags = (current->mm) ? |
| 466 | (current->mm->flags & MMF_INIT_MASK) : default_dump_filter; |
Oleg Nesterov | 999d9fc | 2008-07-25 01:47:41 -0700 | [diff] [blame] | 467 | mm->core_state = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 468 | mm->nr_ptes = 0; |
KAMEZAWA Hiroyuki | d559db0 | 2010-03-05 13:41:39 -0800 | [diff] [blame] | 469 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 470 | spin_lock_init(&mm->page_table_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | mm->free_area_cache = TASK_UNMAPPED_BASE; |
Wolfgang Wander | 1363c3c | 2005-06-21 17:14:49 -0700 | [diff] [blame] | 472 | mm->cached_hole_size = ~0UL; |
Alexey Dobriyan | 858f099 | 2009-09-23 15:57:32 -0700 | [diff] [blame] | 473 | mm_init_aio(mm); |
Balbir Singh | cf475ad | 2008-04-29 01:00:16 -0700 | [diff] [blame] | 474 | mm_init_owner(mm, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | |
| 476 | if (likely(!mm_alloc_pgd(mm))) { |
| 477 | mm->def_flags = 0; |
Andrea Arcangeli | cddb8a5 | 2008-07-28 15:46:29 -0700 | [diff] [blame] | 478 | mmu_notifier_mm_init(mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 479 | return mm; |
| 480 | } |
Pavel Emelianov | 78fb746 | 2008-02-07 00:13:51 -0800 | [diff] [blame] | 481 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 482 | free_mm(mm); |
| 483 | return NULL; |
| 484 | } |
| 485 | |
| 486 | /* |
| 487 | * Allocate and initialize an mm_struct. |
| 488 | */ |
| 489 | struct mm_struct * mm_alloc(void) |
| 490 | { |
| 491 | struct mm_struct * mm; |
| 492 | |
| 493 | mm = allocate_mm(); |
| 494 | if (mm) { |
| 495 | memset(mm, 0, sizeof(*mm)); |
Pavel Emelianov | 78fb746 | 2008-02-07 00:13:51 -0800 | [diff] [blame] | 496 | mm = mm_init(mm, current); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | } |
| 498 | return mm; |
| 499 | } |
| 500 | |
| 501 | /* |
| 502 | * Called when the last reference to the mm |
| 503 | * is dropped: either by a lazy thread or by |
| 504 | * mmput. Free the page directory and the mm. |
| 505 | */ |
Harvey Harrison | 7ad5b3a | 2008-02-08 04:19:53 -0800 | [diff] [blame] | 506 | void __mmdrop(struct mm_struct *mm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | { |
| 508 | BUG_ON(mm == &init_mm); |
| 509 | mm_free_pgd(mm); |
| 510 | destroy_context(mm); |
Andrea Arcangeli | cddb8a5 | 2008-07-28 15:46:29 -0700 | [diff] [blame] | 511 | mmu_notifier_mm_destroy(mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | free_mm(mm); |
| 513 | } |
Avi Kivity | 6d4e4c4 | 2007-11-21 16:41:05 +0200 | [diff] [blame] | 514 | EXPORT_SYMBOL_GPL(__mmdrop); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 515 | |
| 516 | /* |
| 517 | * Decrement the use count and release all resources for an mm. |
| 518 | */ |
| 519 | void mmput(struct mm_struct *mm) |
| 520 | { |
Andrew Morton | 0ae26f1 | 2006-06-23 02:05:15 -0700 | [diff] [blame] | 521 | might_sleep(); |
| 522 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | if (atomic_dec_and_test(&mm->mm_users)) { |
| 524 | exit_aio(mm); |
Andrea Arcangeli | 1c2fb7a | 2009-09-21 17:02:22 -0700 | [diff] [blame] | 525 | ksm_exit(mm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | exit_mmap(mm); |
Matt Helsley | 925d1c4 | 2008-04-29 01:01:36 -0700 | [diff] [blame] | 527 | set_mm_exe_file(mm, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 528 | if (!list_empty(&mm->mmlist)) { |
| 529 | spin_lock(&mmlist_lock); |
| 530 | list_del(&mm->mmlist); |
| 531 | spin_unlock(&mmlist_lock); |
| 532 | } |
| 533 | put_swap_token(mm); |
Hiroshi Shimamoto | 801460d | 2009-09-23 15:57:41 -0700 | [diff] [blame] | 534 | if (mm->binfmt) |
| 535 | module_put(mm->binfmt->module); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 536 | mmdrop(mm); |
| 537 | } |
| 538 | } |
| 539 | EXPORT_SYMBOL_GPL(mmput); |
| 540 | |
| 541 | /** |
| 542 | * get_task_mm - acquire a reference to the task's mm |
| 543 | * |
Oleg Nesterov | 246bb0b | 2008-07-25 01:47:38 -0700 | [diff] [blame] | 544 | * Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 545 | * this kernel workthread has transiently adopted a user mm with use_mm, |
| 546 | * to do its AIO) is not set and if so returns a reference to it, after |
| 547 | * bumping up the use count. User must release the mm via mmput() |
| 548 | * after use. Typically used by /proc and ptrace. |
| 549 | */ |
| 550 | struct mm_struct *get_task_mm(struct task_struct *task) |
| 551 | { |
| 552 | struct mm_struct *mm; |
| 553 | |
| 554 | task_lock(task); |
| 555 | mm = task->mm; |
| 556 | if (mm) { |
Oleg Nesterov | 246bb0b | 2008-07-25 01:47:38 -0700 | [diff] [blame] | 557 | if (task->flags & PF_KTHREAD) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 558 | mm = NULL; |
| 559 | else |
| 560 | atomic_inc(&mm->mm_users); |
| 561 | } |
| 562 | task_unlock(task); |
| 563 | return mm; |
| 564 | } |
| 565 | EXPORT_SYMBOL_GPL(get_task_mm); |
| 566 | |
| 567 | /* Please note the differences between mmput and mm_release. |
| 568 | * mmput is called whenever we stop holding onto a mm_struct, |
| 569 | * error success whatever. |
| 570 | * |
| 571 | * mm_release is called after a mm_struct has been removed |
| 572 | * from the current process. |
| 573 | * |
| 574 | * This difference is important for error handling, when we |
| 575 | * only half set up a mm_struct for a new process and need to restore |
| 576 | * the old one. Because we mmput the new mm_struct before |
| 577 | * restoring the old one. . . |
| 578 | * Eric Biederman 10 January 1998 |
| 579 | */ |
| 580 | void mm_release(struct task_struct *tsk, struct mm_struct *mm) |
| 581 | { |
| 582 | struct completion *vfork_done = tsk->vfork_done; |
| 583 | |
Linus Torvalds | 8141c7f | 2008-11-15 10:20:36 -0800 | [diff] [blame] | 584 | /* Get rid of any futexes when releasing the mm */ |
| 585 | #ifdef CONFIG_FUTEX |
Peter Zijlstra | fc6b177 | 2009-10-05 18:17:32 +0200 | [diff] [blame] | 586 | if (unlikely(tsk->robust_list)) { |
Linus Torvalds | 8141c7f | 2008-11-15 10:20:36 -0800 | [diff] [blame] | 587 | exit_robust_list(tsk); |
Peter Zijlstra | fc6b177 | 2009-10-05 18:17:32 +0200 | [diff] [blame] | 588 | tsk->robust_list = NULL; |
| 589 | } |
Linus Torvalds | 8141c7f | 2008-11-15 10:20:36 -0800 | [diff] [blame] | 590 | #ifdef CONFIG_COMPAT |
Peter Zijlstra | fc6b177 | 2009-10-05 18:17:32 +0200 | [diff] [blame] | 591 | if (unlikely(tsk->compat_robust_list)) { |
Linus Torvalds | 8141c7f | 2008-11-15 10:20:36 -0800 | [diff] [blame] | 592 | compat_exit_robust_list(tsk); |
Peter Zijlstra | fc6b177 | 2009-10-05 18:17:32 +0200 | [diff] [blame] | 593 | tsk->compat_robust_list = NULL; |
| 594 | } |
Linus Torvalds | 8141c7f | 2008-11-15 10:20:36 -0800 | [diff] [blame] | 595 | #endif |
Thomas Gleixner | 322a2c1 | 2009-10-05 18:18:03 +0200 | [diff] [blame] | 596 | if (unlikely(!list_empty(&tsk->pi_state_list))) |
| 597 | exit_pi_state_list(tsk); |
Linus Torvalds | 8141c7f | 2008-11-15 10:20:36 -0800 | [diff] [blame] | 598 | #endif |
| 599 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | /* Get rid of any cached register state */ |
| 601 | deactivate_mm(tsk, mm); |
| 602 | |
| 603 | /* notify parent sleeping on vfork() */ |
| 604 | if (vfork_done) { |
| 605 | tsk->vfork_done = NULL; |
| 606 | complete(vfork_done); |
| 607 | } |
Roland McGrath | fec1d01 | 2006-12-06 20:36:34 -0800 | [diff] [blame] | 608 | |
| 609 | /* |
| 610 | * If we're exiting normally, clear a user-space tid field if |
| 611 | * requested. We leave this alone when dying by signal, to leave |
| 612 | * the value intact in a core dump, and to save the unnecessary |
| 613 | * trouble otherwise. Userland only wants this done for a sys_exit. |
| 614 | */ |
Eric Dumazet | 9c8a822 | 2009-08-06 15:09:28 -0700 | [diff] [blame] | 615 | if (tsk->clear_child_tid) { |
| 616 | if (!(tsk->flags & PF_SIGNALED) && |
| 617 | atomic_read(&mm->mm_users) > 1) { |
| 618 | /* |
| 619 | * We don't check the error code - if userspace has |
| 620 | * not set up a proper pointer then tough luck. |
| 621 | */ |
| 622 | put_user(0, tsk->clear_child_tid); |
| 623 | sys_futex(tsk->clear_child_tid, FUTEX_WAKE, |
| 624 | 1, NULL, NULL, 0); |
| 625 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 626 | tsk->clear_child_tid = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 627 | } |
| 628 | } |
| 629 | |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 630 | /* |
| 631 | * Allocate a new mm structure and copy contents from the |
| 632 | * mm structure of the passed in task structure. |
| 633 | */ |
Carsten Otte | 402b086 | 2008-03-25 18:47:10 +0100 | [diff] [blame] | 634 | struct mm_struct *dup_mm(struct task_struct *tsk) |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 635 | { |
| 636 | struct mm_struct *mm, *oldmm = current->mm; |
| 637 | int err; |
| 638 | |
| 639 | if (!oldmm) |
| 640 | return NULL; |
| 641 | |
| 642 | mm = allocate_mm(); |
| 643 | if (!mm) |
| 644 | goto fail_nomem; |
| 645 | |
| 646 | memcpy(mm, oldmm, sizeof(*mm)); |
| 647 | |
Ashwin Chaugule | 7602bdf | 2006-12-06 20:31:57 -0800 | [diff] [blame] | 648 | /* Initializing for Swap token stuff */ |
| 649 | mm->token_priority = 0; |
| 650 | mm->last_interval = 0; |
| 651 | |
Pavel Emelianov | 78fb746 | 2008-02-07 00:13:51 -0800 | [diff] [blame] | 652 | if (!mm_init(mm, tsk)) |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 653 | goto fail_nomem; |
| 654 | |
| 655 | if (init_new_context(tsk, mm)) |
| 656 | goto fail_nocontext; |
| 657 | |
Matt Helsley | 925d1c4 | 2008-04-29 01:01:36 -0700 | [diff] [blame] | 658 | dup_mm_exe_file(oldmm, mm); |
| 659 | |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 660 | err = dup_mmap(mm, oldmm); |
| 661 | if (err) |
| 662 | goto free_pt; |
| 663 | |
| 664 | mm->hiwater_rss = get_mm_rss(mm); |
| 665 | mm->hiwater_vm = mm->total_vm; |
| 666 | |
Hiroshi Shimamoto | 801460d | 2009-09-23 15:57:41 -0700 | [diff] [blame] | 667 | if (mm->binfmt && !try_module_get(mm->binfmt->module)) |
| 668 | goto free_pt; |
| 669 | |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 670 | return mm; |
| 671 | |
| 672 | free_pt: |
Hiroshi Shimamoto | 801460d | 2009-09-23 15:57:41 -0700 | [diff] [blame] | 673 | /* don't put binfmt in mmput, we haven't got module yet */ |
| 674 | mm->binfmt = NULL; |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 675 | mmput(mm); |
| 676 | |
| 677 | fail_nomem: |
| 678 | return NULL; |
| 679 | |
| 680 | fail_nocontext: |
| 681 | /* |
| 682 | * If init_new_context() failed, we cannot use mmput() to free the mm |
| 683 | * because it calls destroy_context() |
| 684 | */ |
| 685 | mm_free_pgd(mm); |
| 686 | free_mm(mm); |
| 687 | return NULL; |
| 688 | } |
| 689 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 690 | static int copy_mm(unsigned long clone_flags, struct task_struct * tsk) |
| 691 | { |
| 692 | struct mm_struct * mm, *oldmm; |
| 693 | int retval; |
| 694 | |
| 695 | tsk->min_flt = tsk->maj_flt = 0; |
| 696 | tsk->nvcsw = tsk->nivcsw = 0; |
Mandeep Singh Baines | 17406b8 | 2009-02-06 15:37:47 -0800 | [diff] [blame] | 697 | #ifdef CONFIG_DETECT_HUNG_TASK |
| 698 | tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw; |
| 699 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 700 | |
| 701 | tsk->mm = NULL; |
| 702 | tsk->active_mm = NULL; |
| 703 | |
| 704 | /* |
| 705 | * Are we cloning a kernel thread? |
| 706 | * |
| 707 | * We need to steal a active VM for that.. |
| 708 | */ |
| 709 | oldmm = current->mm; |
| 710 | if (!oldmm) |
| 711 | return 0; |
| 712 | |
| 713 | if (clone_flags & CLONE_VM) { |
| 714 | atomic_inc(&oldmm->mm_users); |
| 715 | mm = oldmm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 716 | goto good_mm; |
| 717 | } |
| 718 | |
| 719 | retval = -ENOMEM; |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 720 | mm = dup_mm(tsk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 721 | if (!mm) |
| 722 | goto fail_nomem; |
| 723 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 724 | good_mm: |
Ashwin Chaugule | 7602bdf | 2006-12-06 20:31:57 -0800 | [diff] [blame] | 725 | /* Initializing for Swap token stuff */ |
| 726 | mm->token_priority = 0; |
| 727 | mm->last_interval = 0; |
| 728 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 | tsk->mm = mm; |
| 730 | tsk->active_mm = mm; |
| 731 | return 0; |
| 732 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 733 | fail_nomem: |
| 734 | return retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 735 | } |
| 736 | |
Alexey Dobriyan | a39bc51 | 2007-10-18 23:41:10 -0700 | [diff] [blame] | 737 | static int copy_fs(unsigned long clone_flags, struct task_struct *tsk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 738 | { |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 739 | struct fs_struct *fs = current->fs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 740 | if (clone_flags & CLONE_FS) { |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 741 | /* tsk->fs is already what we want */ |
| 742 | write_lock(&fs->lock); |
| 743 | if (fs->in_exec) { |
| 744 | write_unlock(&fs->lock); |
| 745 | return -EAGAIN; |
| 746 | } |
| 747 | fs->users++; |
| 748 | write_unlock(&fs->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 749 | return 0; |
| 750 | } |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 751 | tsk->fs = copy_fs_struct(fs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 752 | if (!tsk->fs) |
| 753 | return -ENOMEM; |
| 754 | return 0; |
| 755 | } |
| 756 | |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 757 | static int copy_files(unsigned long clone_flags, struct task_struct * tsk) |
| 758 | { |
| 759 | struct files_struct *oldf, *newf; |
| 760 | int error = 0; |
| 761 | |
| 762 | /* |
| 763 | * A background process may not have any files ... |
| 764 | */ |
| 765 | oldf = current->files; |
| 766 | if (!oldf) |
| 767 | goto out; |
| 768 | |
| 769 | if (clone_flags & CLONE_FILES) { |
| 770 | atomic_inc(&oldf->count); |
| 771 | goto out; |
| 772 | } |
| 773 | |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 774 | newf = dup_fd(oldf, &error); |
| 775 | if (!newf) |
| 776 | goto out; |
| 777 | |
| 778 | tsk->files = newf; |
| 779 | error = 0; |
| 780 | out: |
| 781 | return error; |
| 782 | } |
| 783 | |
Jens Axboe | fadad878 | 2008-01-24 08:54:47 +0100 | [diff] [blame] | 784 | static int copy_io(unsigned long clone_flags, struct task_struct *tsk) |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 785 | { |
| 786 | #ifdef CONFIG_BLOCK |
| 787 | struct io_context *ioc = current->io_context; |
| 788 | |
| 789 | if (!ioc) |
| 790 | return 0; |
Jens Axboe | fadad878 | 2008-01-24 08:54:47 +0100 | [diff] [blame] | 791 | /* |
| 792 | * Share io context with parent, if CLONE_IO is set |
| 793 | */ |
| 794 | if (clone_flags & CLONE_IO) { |
| 795 | tsk->io_context = ioc_task_link(ioc); |
| 796 | if (unlikely(!tsk->io_context)) |
| 797 | return -ENOMEM; |
| 798 | } else if (ioprio_valid(ioc->ioprio)) { |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 799 | tsk->io_context = alloc_io_context(GFP_KERNEL, -1); |
| 800 | if (unlikely(!tsk->io_context)) |
| 801 | return -ENOMEM; |
| 802 | |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 803 | tsk->io_context->ioprio = ioc->ioprio; |
| 804 | } |
| 805 | #endif |
| 806 | return 0; |
| 807 | } |
| 808 | |
Alexey Dobriyan | a39bc51 | 2007-10-18 23:41:10 -0700 | [diff] [blame] | 809 | static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 810 | { |
| 811 | struct sighand_struct *sig; |
| 812 | |
Zhaolei | 6034880 | 2009-01-06 14:40:46 -0800 | [diff] [blame] | 813 | if (clone_flags & CLONE_SIGHAND) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 814 | atomic_inc(¤t->sighand->count); |
| 815 | return 0; |
| 816 | } |
| 817 | sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
Ingo Molnar | e56d090 | 2006-01-08 01:01:37 -0800 | [diff] [blame] | 818 | rcu_assign_pointer(tsk->sighand, sig); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 819 | if (!sig) |
| 820 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 821 | atomic_set(&sig->count, 1); |
| 822 | memcpy(sig->action, current->sighand->action, sizeof(sig->action)); |
| 823 | return 0; |
| 824 | } |
| 825 | |
Oleg Nesterov | a7e5328 | 2006-03-28 16:11:27 -0800 | [diff] [blame] | 826 | void __cleanup_sighand(struct sighand_struct *sighand) |
Oleg Nesterov | c81addc | 2006-03-28 16:11:17 -0800 | [diff] [blame] | 827 | { |
Oleg Nesterov | c81addc | 2006-03-28 16:11:17 -0800 | [diff] [blame] | 828 | if (atomic_dec_and_test(&sighand->count)) |
| 829 | kmem_cache_free(sighand_cachep, sighand); |
| 830 | } |
| 831 | |
Frank Mayhar | f06febc | 2008-09-12 09:54:39 -0700 | [diff] [blame] | 832 | |
| 833 | /* |
| 834 | * Initialize POSIX timer handling for a thread group. |
| 835 | */ |
| 836 | static void posix_cpu_timers_init_group(struct signal_struct *sig) |
| 837 | { |
Jiri Slaby | 78d7d40 | 2010-03-05 13:42:54 -0800 | [diff] [blame] | 838 | unsigned long cpu_limit; |
| 839 | |
Frank Mayhar | f06febc | 2008-09-12 09:54:39 -0700 | [diff] [blame] | 840 | /* Thread group counters. */ |
| 841 | thread_group_cputime_init(sig); |
| 842 | |
Jiri Slaby | 78d7d40 | 2010-03-05 13:42:54 -0800 | [diff] [blame] | 843 | cpu_limit = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur); |
| 844 | if (cpu_limit != RLIM_INFINITY) { |
| 845 | sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit); |
Oleg Nesterov | 6279a751 | 2009-03-27 01:06:07 +0100 | [diff] [blame] | 846 | sig->cputimer.running = 1; |
| 847 | } |
| 848 | |
Frank Mayhar | f06febc | 2008-09-12 09:54:39 -0700 | [diff] [blame] | 849 | /* The timer lists. */ |
| 850 | INIT_LIST_HEAD(&sig->cpu_timers[0]); |
| 851 | INIT_LIST_HEAD(&sig->cpu_timers[1]); |
| 852 | INIT_LIST_HEAD(&sig->cpu_timers[2]); |
| 853 | } |
| 854 | |
Alexey Dobriyan | a39bc51 | 2007-10-18 23:41:10 -0700 | [diff] [blame] | 855 | static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 856 | { |
| 857 | struct signal_struct *sig; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | |
Oleg Nesterov | 4ab6c08 | 2009-08-26 14:29:24 -0700 | [diff] [blame] | 859 | if (clone_flags & CLONE_THREAD) |
Peter Zijlstra | 490dea4 | 2008-11-24 17:06:57 +0100 | [diff] [blame] | 860 | return 0; |
Oleg Nesterov | 6279a751 | 2009-03-27 01:06:07 +0100 | [diff] [blame] | 861 | |
Veaceslav Falico | a56704e | 2010-03-10 15:23:01 -0800 | [diff] [blame] | 862 | sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | tsk->signal = sig; |
| 864 | if (!sig) |
| 865 | return -ENOMEM; |
| 866 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 867 | atomic_set(&sig->count, 1); |
| 868 | atomic_set(&sig->live, 1); |
| 869 | init_waitqueue_head(&sig->wait_chldexit); |
Sukadev Bhattiprolu | b3bfa0c | 2009-04-02 16:58:08 -0700 | [diff] [blame] | 870 | if (clone_flags & CLONE_NEWPID) |
| 871 | sig->flags |= SIGNAL_UNKILLABLE; |
Oleg Nesterov | db51aec | 2008-04-30 00:52:52 -0700 | [diff] [blame] | 872 | sig->curr_target = tsk; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 873 | init_sigpending(&sig->shared_pending); |
| 874 | INIT_LIST_HEAD(&sig->posix_timers); |
| 875 | |
Thomas Gleixner | c9cb2e3 | 2007-02-16 01:27:49 -0800 | [diff] [blame] | 876 | hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 877 | sig->real_timer.function = it_real_fn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 878 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 879 | task_lock(current->group_leader); |
| 880 | memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim); |
| 881 | task_unlock(current->group_leader); |
| 882 | |
Oleg Nesterov | 6279a751 | 2009-03-27 01:06:07 +0100 | [diff] [blame] | 883 | posix_cpu_timers_init_group(sig); |
| 884 | |
Miloslav Trmac | 522ed77 | 2007-07-15 23:40:56 -0700 | [diff] [blame] | 885 | tty_audit_fork(sig); |
| 886 | |
KOSAKI Motohiro | 28b83c5 | 2009-09-21 17:03:13 -0700 | [diff] [blame] | 887 | sig->oom_adj = current->signal->oom_adj; |
| 888 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 889 | return 0; |
| 890 | } |
| 891 | |
Oleg Nesterov | 6b3934e | 2006-03-28 16:11:16 -0800 | [diff] [blame] | 892 | void __cleanup_signal(struct signal_struct *sig) |
| 893 | { |
Frank Mayhar | f06febc | 2008-09-12 09:54:39 -0700 | [diff] [blame] | 894 | thread_group_cputime_free(sig); |
Alan Cox | 9c9f4de | 2008-10-13 10:37:26 +0100 | [diff] [blame] | 895 | tty_kref_put(sig->tty); |
Oleg Nesterov | 6b3934e | 2006-03-28 16:11:16 -0800 | [diff] [blame] | 896 | kmem_cache_free(signal_cachep, sig); |
| 897 | } |
| 898 | |
Alexey Dobriyan | a39bc51 | 2007-10-18 23:41:10 -0700 | [diff] [blame] | 899 | static void copy_flags(unsigned long clone_flags, struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 900 | { |
| 901 | unsigned long new_flags = p->flags; |
| 902 | |
Rafael J. Wysocki | 8314418 | 2007-07-17 04:03:35 -0700 | [diff] [blame] | 903 | new_flags &= ~PF_SUPERPRIV; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 904 | new_flags |= PF_FORKNOEXEC; |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 905 | new_flags |= PF_STARTING; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 906 | p->flags = new_flags; |
Rafael J. Wysocki | 2e13189 | 2007-10-18 03:04:45 -0700 | [diff] [blame] | 907 | clear_freeze_flag(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 908 | } |
| 909 | |
Heiko Carstens | 17da2bd | 2009-01-14 14:14:10 +0100 | [diff] [blame] | 910 | SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 911 | { |
| 912 | current->clear_child_tid = tidptr; |
| 913 | |
Pavel Emelyanov | b488893 | 2007-10-18 23:40:14 -0700 | [diff] [blame] | 914 | return task_pid_vnr(current); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 915 | } |
| 916 | |
Alexey Dobriyan | a39bc51 | 2007-10-18 23:41:10 -0700 | [diff] [blame] | 917 | static void rt_mutex_init_task(struct task_struct *p) |
Ingo Molnar | 23f78d4a | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 918 | { |
Thomas Gleixner | 1d61548 | 2009-11-17 14:54:03 +0100 | [diff] [blame] | 919 | raw_spin_lock_init(&p->pi_lock); |
Zilvinas Valinskas | e29e175 | 2007-03-16 13:38:34 -0800 | [diff] [blame] | 920 | #ifdef CONFIG_RT_MUTEXES |
Thomas Gleixner | 1d61548 | 2009-11-17 14:54:03 +0100 | [diff] [blame] | 921 | plist_head_init_raw(&p->pi_waiters, &p->pi_lock); |
Ingo Molnar | 23f78d4a | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 922 | p->pi_blocked_on = NULL; |
Ingo Molnar | 23f78d4a | 2006-06-27 02:54:53 -0700 | [diff] [blame] | 923 | #endif |
| 924 | } |
| 925 | |
Balbir Singh | cf475ad | 2008-04-29 01:00:16 -0700 | [diff] [blame] | 926 | #ifdef CONFIG_MM_OWNER |
| 927 | void mm_init_owner(struct mm_struct *mm, struct task_struct *p) |
| 928 | { |
| 929 | mm->owner = p; |
| 930 | } |
| 931 | #endif /* CONFIG_MM_OWNER */ |
| 932 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 933 | /* |
Frank Mayhar | f06febc | 2008-09-12 09:54:39 -0700 | [diff] [blame] | 934 | * Initialize POSIX timer handling for a single task. |
| 935 | */ |
| 936 | static void posix_cpu_timers_init(struct task_struct *tsk) |
| 937 | { |
| 938 | tsk->cputime_expires.prof_exp = cputime_zero; |
| 939 | tsk->cputime_expires.virt_exp = cputime_zero; |
| 940 | tsk->cputime_expires.sched_exp = 0; |
| 941 | INIT_LIST_HEAD(&tsk->cpu_timers[0]); |
| 942 | INIT_LIST_HEAD(&tsk->cpu_timers[1]); |
| 943 | INIT_LIST_HEAD(&tsk->cpu_timers[2]); |
| 944 | } |
| 945 | |
| 946 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 947 | * This creates a new process as a copy of the old one, |
| 948 | * but does not actually start it yet. |
| 949 | * |
| 950 | * It copies the registers, and all the appropriate |
| 951 | * parts of the process environment (as per the clone |
| 952 | * flags). The actual kick-off is left to the caller. |
| 953 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 954 | static struct task_struct *copy_process(unsigned long clone_flags, |
| 955 | unsigned long stack_start, |
| 956 | struct pt_regs *regs, |
| 957 | unsigned long stack_size, |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 958 | int __user *child_tidptr, |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 959 | struct pid *pid, |
| 960 | int trace) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 961 | { |
| 962 | int retval; |
Mariusz Kozlowski | a24efe6 | 2007-10-18 23:41:09 -0700 | [diff] [blame] | 963 | struct task_struct *p; |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 964 | int cgroup_callbacks_done = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 965 | |
| 966 | if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) |
| 967 | return ERR_PTR(-EINVAL); |
| 968 | |
| 969 | /* |
| 970 | * Thread groups must share signals as well, and detached threads |
| 971 | * can only be started up within the thread group. |
| 972 | */ |
| 973 | if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND)) |
| 974 | return ERR_PTR(-EINVAL); |
| 975 | |
| 976 | /* |
| 977 | * Shared signal handlers imply shared VM. By way of the above, |
| 978 | * thread groups also imply shared VM. Blocking this case allows |
| 979 | * for various simplifications in other code. |
| 980 | */ |
| 981 | if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) |
| 982 | return ERR_PTR(-EINVAL); |
| 983 | |
Sukadev Bhattiprolu | 123be07 | 2009-09-23 15:57:20 -0700 | [diff] [blame] | 984 | /* |
| 985 | * Siblings of global init remain as zombies on exit since they are |
| 986 | * not reaped by their parent (swapper). To solve this and to avoid |
| 987 | * multi-rooted process trees, prevent global and container-inits |
| 988 | * from creating siblings. |
| 989 | */ |
| 990 | if ((clone_flags & CLONE_PARENT) && |
| 991 | current->signal->flags & SIGNAL_UNKILLABLE) |
| 992 | return ERR_PTR(-EINVAL); |
| 993 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 994 | retval = security_task_create(clone_flags); |
| 995 | if (retval) |
| 996 | goto fork_out; |
| 997 | |
| 998 | retval = -ENOMEM; |
| 999 | p = dup_task_struct(current); |
| 1000 | if (!p) |
| 1001 | goto fork_out; |
| 1002 | |
Steven Rostedt | f7e8b61 | 2009-06-02 16:39:48 -0400 | [diff] [blame] | 1003 | ftrace_graph_init_task(p); |
| 1004 | |
Peter Zijlstra | bea493a | 2006-10-17 00:10:33 -0700 | [diff] [blame] | 1005 | rt_mutex_init_task(p); |
| 1006 | |
Ingo Molnar | d12c1a3 | 2008-07-14 12:09:28 +0200 | [diff] [blame] | 1007 | #ifdef CONFIG_PROVE_LOCKING |
Ingo Molnar | de30a2b | 2006-07-03 00:24:42 -0700 | [diff] [blame] | 1008 | DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled); |
| 1009 | DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled); |
| 1010 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1011 | retval = -EAGAIN; |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 1012 | if (atomic_read(&p->real_cred->user->processes) >= |
Jiri Slaby | 78d7d40 | 2010-03-05 13:42:54 -0800 | [diff] [blame] | 1013 | task_rlimit(p, RLIMIT_NPROC)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1014 | if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) && |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 1015 | p->real_cred->user != INIT_USER) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1016 | goto bad_fork_free; |
| 1017 | } |
| 1018 | |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 1019 | retval = copy_creds(p, clone_flags); |
| 1020 | if (retval < 0) |
| 1021 | goto bad_fork_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1022 | |
| 1023 | /* |
| 1024 | * If multiple threads are within copy_process(), then this check |
| 1025 | * triggers too late. This doesn't hurt, the check is only there |
| 1026 | * to stop root fork bombs. |
| 1027 | */ |
Li Zefan | 04ec93f | 2009-02-06 08:17:19 +0000 | [diff] [blame] | 1028 | retval = -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1029 | if (nr_threads >= max_threads) |
| 1030 | goto bad_fork_cleanup_count; |
| 1031 | |
Al Viro | a1261f5 | 2005-11-13 16:06:55 -0800 | [diff] [blame] | 1032 | if (!try_module_get(task_thread_info(p)->exec_domain->module)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1033 | goto bad_fork_cleanup_count; |
| 1034 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1035 | p->did_exec = 0; |
Shailabh Nagar | ca74e92 | 2006-07-14 00:24:36 -0700 | [diff] [blame] | 1036 | delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1037 | copy_flags(clone_flags, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1038 | INIT_LIST_HEAD(&p->children); |
| 1039 | INIT_LIST_HEAD(&p->sibling); |
Paul E. McKenney | f41d911 | 2009-08-22 13:56:52 -0700 | [diff] [blame] | 1040 | rcu_copy_process(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1041 | p->vfork_done = NULL; |
| 1042 | spin_lock_init(&p->alloc_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1043 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1044 | init_sigpending(&p->pending); |
| 1045 | |
| 1046 | p->utime = cputime_zero; |
| 1047 | p->stime = cputime_zero; |
Laurent Vivier | 9ac5231 | 2007-10-15 17:00:19 +0200 | [diff] [blame] | 1048 | p->gtime = cputime_zero; |
Michael Neuling | c66f08b | 2007-10-18 03:06:34 -0700 | [diff] [blame] | 1049 | p->utimescaled = cputime_zero; |
| 1050 | p->stimescaled = cputime_zero; |
Hidetoshi Seto | d99ca3b | 2009-12-02 17:26:47 +0900 | [diff] [blame] | 1051 | #ifndef CONFIG_VIRT_CPU_ACCOUNTING |
Peter Zijlstra | 73a2bcb | 2007-10-29 21:18:11 +0100 | [diff] [blame] | 1052 | p->prev_utime = cputime_zero; |
Balbir Singh | 9301899 | 2007-10-30 00:26:32 +0100 | [diff] [blame] | 1053 | p->prev_stime = cputime_zero; |
Hidetoshi Seto | d99ca3b | 2009-12-02 17:26:47 +0900 | [diff] [blame] | 1054 | #endif |
KAMEZAWA Hiroyuki | a3a2e76 | 2010-04-06 14:34:42 -0700 | [diff] [blame] | 1055 | #if defined(SPLIT_RSS_COUNTING) |
| 1056 | memset(&p->rss_stat, 0, sizeof(p->rss_stat)); |
| 1057 | #endif |
Balbir Singh | 172ba84 | 2007-07-09 18:52:00 +0200 | [diff] [blame] | 1058 | |
Arjan van de Ven | 6976675 | 2008-09-01 15:52:40 -0700 | [diff] [blame] | 1059 | p->default_timer_slack_ns = current->timer_slack_ns; |
| 1060 | |
Andrea Righi | 5995477 | 2008-07-27 17:29:15 +0200 | [diff] [blame] | 1061 | task_io_accounting_init(&p->ioac); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1062 | acct_clear_integrals(p); |
| 1063 | |
Frank Mayhar | f06febc | 2008-09-12 09:54:39 -0700 | [diff] [blame] | 1064 | posix_cpu_timers_init(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1065 | |
| 1066 | p->lock_depth = -1; /* -1 = no lock */ |
| 1067 | do_posix_clock_monotonic_gettime(&p->start_time); |
Tomas Janousek | 924b42d | 2007-07-15 23:39:42 -0700 | [diff] [blame] | 1068 | p->real_start_time = p->start_time; |
| 1069 | monotonic_to_bootbased(&p->real_start_time); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1070 | p->io_context = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1071 | p->audit_context = NULL; |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 1072 | cgroup_fork(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1073 | #ifdef CONFIG_NUMA |
Lee Schermerhorn | 846a16b | 2008-04-28 02:13:09 -0700 | [diff] [blame] | 1074 | p->mempolicy = mpol_dup(p->mempolicy); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1075 | if (IS_ERR(p->mempolicy)) { |
| 1076 | retval = PTR_ERR(p->mempolicy); |
| 1077 | p->mempolicy = NULL; |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 1078 | goto bad_fork_cleanup_cgroup; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1079 | } |
Paul Jackson | c61afb1 | 2006-03-24 03:16:08 -0800 | [diff] [blame] | 1080 | mpol_fix_fork_child_flag(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1081 | #endif |
Ingo Molnar | de30a2b | 2006-07-03 00:24:42 -0700 | [diff] [blame] | 1082 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 1083 | p->irq_events = 0; |
Russell King | b36e475 | 2006-08-27 12:26:34 +0100 | [diff] [blame] | 1084 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
| 1085 | p->hardirqs_enabled = 1; |
| 1086 | #else |
Ingo Molnar | de30a2b | 2006-07-03 00:24:42 -0700 | [diff] [blame] | 1087 | p->hardirqs_enabled = 0; |
Russell King | b36e475 | 2006-08-27 12:26:34 +0100 | [diff] [blame] | 1088 | #endif |
Ingo Molnar | de30a2b | 2006-07-03 00:24:42 -0700 | [diff] [blame] | 1089 | p->hardirq_enable_ip = 0; |
| 1090 | p->hardirq_enable_event = 0; |
| 1091 | p->hardirq_disable_ip = _THIS_IP_; |
| 1092 | p->hardirq_disable_event = 0; |
| 1093 | p->softirqs_enabled = 1; |
| 1094 | p->softirq_enable_ip = _THIS_IP_; |
| 1095 | p->softirq_enable_event = 0; |
| 1096 | p->softirq_disable_ip = 0; |
| 1097 | p->softirq_disable_event = 0; |
| 1098 | p->hardirq_context = 0; |
| 1099 | p->softirq_context = 0; |
| 1100 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1101 | #ifdef CONFIG_LOCKDEP |
| 1102 | p->lockdep_depth = 0; /* no locks held yet */ |
| 1103 | p->curr_chain_key = 0; |
| 1104 | p->lockdep_recursion = 0; |
| 1105 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1106 | |
Ingo Molnar | 408894e | 2006-01-09 15:59:20 -0800 | [diff] [blame] | 1107 | #ifdef CONFIG_DEBUG_MUTEXES |
| 1108 | p->blocked_on = NULL; /* not blocked yet */ |
| 1109 | #endif |
KAMEZAWA Hiroyuki | 569b846 | 2009-12-15 16:47:03 -0800 | [diff] [blame] | 1110 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
| 1111 | p->memcg_batch.do_batch = 0; |
| 1112 | p->memcg_batch.memcg = NULL; |
| 1113 | #endif |
Markus Metzger | 0f48140 | 2009-04-03 16:43:48 +0200 | [diff] [blame] | 1114 | |
| 1115 | p->bts = NULL; |
Ingo Molnar | 408894e | 2006-01-09 15:59:20 -0800 | [diff] [blame] | 1116 | |
Stefani Seibold | d899bf7 | 2009-09-22 16:45:40 -0700 | [diff] [blame] | 1117 | p->stack_start = stack_start; |
| 1118 | |
Srivatsa Vaddagiri | 3c90e6e | 2007-11-09 22:39:39 +0100 | [diff] [blame] | 1119 | /* Perform scheduler related setup. Assign this task to a CPU. */ |
| 1120 | sched_fork(p, clone_flags); |
Peter Zijlstra | 6ab423e | 2009-05-25 14:45:27 +0200 | [diff] [blame] | 1121 | |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1122 | retval = perf_event_init_task(p); |
Peter Zijlstra | 6ab423e | 2009-05-25 14:45:27 +0200 | [diff] [blame] | 1123 | if (retval) |
| 1124 | goto bad_fork_cleanup_policy; |
Srivatsa Vaddagiri | 3c90e6e | 2007-11-09 22:39:39 +0100 | [diff] [blame] | 1125 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1126 | if ((retval = audit_alloc(p))) |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 1127 | goto bad_fork_cleanup_policy; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1128 | /* copy all the process information */ |
| 1129 | if ((retval = copy_semundo(clone_flags, p))) |
| 1130 | goto bad_fork_cleanup_audit; |
| 1131 | if ((retval = copy_files(clone_flags, p))) |
| 1132 | goto bad_fork_cleanup_semundo; |
| 1133 | if ((retval = copy_fs(clone_flags, p))) |
| 1134 | goto bad_fork_cleanup_files; |
| 1135 | if ((retval = copy_sighand(clone_flags, p))) |
| 1136 | goto bad_fork_cleanup_fs; |
| 1137 | if ((retval = copy_signal(clone_flags, p))) |
| 1138 | goto bad_fork_cleanup_sighand; |
| 1139 | if ((retval = copy_mm(clone_flags, p))) |
| 1140 | goto bad_fork_cleanup_signal; |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 1141 | if ((retval = copy_namespaces(clone_flags, p))) |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 1142 | goto bad_fork_cleanup_mm; |
Jens Axboe | fadad878 | 2008-01-24 08:54:47 +0100 | [diff] [blame] | 1143 | if ((retval = copy_io(clone_flags, p))) |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1144 | goto bad_fork_cleanup_namespaces; |
Alexey Dobriyan | 6f2c55b | 2009-04-02 16:56:59 -0700 | [diff] [blame] | 1145 | retval = copy_thread(clone_flags, stack_start, stack_size, p, regs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1146 | if (retval) |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1147 | goto bad_fork_cleanup_io; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1148 | |
Pavel Emelyanov | 425fb2b | 2007-10-18 23:40:07 -0700 | [diff] [blame] | 1149 | if (pid != &init_struct_pid) { |
| 1150 | retval = -ENOMEM; |
Eric W. Biederman | 61bce0f | 2009-01-07 18:08:49 -0800 | [diff] [blame] | 1151 | pid = alloc_pid(p->nsproxy->pid_ns); |
Pavel Emelyanov | 425fb2b | 2007-10-18 23:40:07 -0700 | [diff] [blame] | 1152 | if (!pid) |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1153 | goto bad_fork_cleanup_io; |
Pavel Emelyanov | 6f4e643 | 2007-10-18 23:40:11 -0700 | [diff] [blame] | 1154 | |
| 1155 | if (clone_flags & CLONE_NEWPID) { |
Eric W. Biederman | 61bce0f | 2009-01-07 18:08:49 -0800 | [diff] [blame] | 1156 | retval = pid_ns_prepare_proc(p->nsproxy->pid_ns); |
Pavel Emelyanov | 6f4e643 | 2007-10-18 23:40:11 -0700 | [diff] [blame] | 1157 | if (retval < 0) |
| 1158 | goto bad_fork_free_pid; |
| 1159 | } |
Pavel Emelyanov | 425fb2b | 2007-10-18 23:40:07 -0700 | [diff] [blame] | 1160 | } |
| 1161 | |
| 1162 | p->pid = pid_nr(pid); |
| 1163 | p->tgid = p->pid; |
| 1164 | if (clone_flags & CLONE_THREAD) |
| 1165 | p->tgid = current->tgid; |
| 1166 | |
Serge E. Hallyn | e885dcd | 2008-07-25 01:47:06 -0700 | [diff] [blame] | 1167 | if (current->nsproxy != p->nsproxy) { |
| 1168 | retval = ns_cgroup_clone(p, pid); |
| 1169 | if (retval) |
Steven Rostedt | f7e8b61 | 2009-06-02 16:39:48 -0400 | [diff] [blame] | 1170 | goto bad_fork_free_pid; |
Serge E. Hallyn | e885dcd | 2008-07-25 01:47:06 -0700 | [diff] [blame] | 1171 | } |
| 1172 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1173 | p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL; |
| 1174 | /* |
| 1175 | * Clear TID on mm_release()? |
| 1176 | */ |
| 1177 | p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL; |
Alexey Dobriyan | 42b2dd0 | 2007-10-16 23:27:30 -0700 | [diff] [blame] | 1178 | #ifdef CONFIG_FUTEX |
Ingo Molnar | 8f17d3a | 2006-03-27 01:16:27 -0800 | [diff] [blame] | 1179 | p->robust_list = NULL; |
| 1180 | #ifdef CONFIG_COMPAT |
| 1181 | p->compat_robust_list = NULL; |
| 1182 | #endif |
Ingo Molnar | c87e283 | 2006-06-27 02:54:58 -0700 | [diff] [blame] | 1183 | INIT_LIST_HEAD(&p->pi_state_list); |
| 1184 | p->pi_state_cache = NULL; |
Alexey Dobriyan | 42b2dd0 | 2007-10-16 23:27:30 -0700 | [diff] [blame] | 1185 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1186 | /* |
GOTO Masanori | f9a3879 | 2006-03-13 21:20:44 -0800 | [diff] [blame] | 1187 | * sigaltstack should be cleared when sharing the same VM |
| 1188 | */ |
| 1189 | if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM) |
| 1190 | p->sas_ss_sp = p->sas_ss_size = 0; |
| 1191 | |
| 1192 | /* |
Oleg Nesterov | 6580807 | 2009-12-15 16:47:16 -0800 | [diff] [blame] | 1193 | * Syscall tracing and stepping should be turned off in the |
| 1194 | * child regardless of CLONE_PTRACE. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1195 | */ |
Oleg Nesterov | 6580807 | 2009-12-15 16:47:16 -0800 | [diff] [blame] | 1196 | user_disable_single_step(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1197 | clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); |
Laurent Vivier | ed75e8d | 2005-09-03 15:57:18 -0700 | [diff] [blame] | 1198 | #ifdef TIF_SYSCALL_EMU |
| 1199 | clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); |
| 1200 | #endif |
Arjan van de Ven | 9745512 | 2008-01-25 21:08:34 +0100 | [diff] [blame] | 1201 | clear_all_latency_tracing(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1202 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1203 | /* ok, now we should be set up.. */ |
| 1204 | p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); |
| 1205 | p->pdeath_signal = 0; |
| 1206 | p->exit_state = 0; |
| 1207 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1208 | /* |
| 1209 | * Ok, make it visible to the rest of the system. |
| 1210 | * We dont wake it up yet. |
| 1211 | */ |
| 1212 | p->group_leader = p; |
Oleg Nesterov | 47e6532 | 2006-03-28 16:11:25 -0800 | [diff] [blame] | 1213 | INIT_LIST_HEAD(&p->thread_group); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1214 | |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 1215 | /* Now that the task is set up, run cgroup callbacks if |
| 1216 | * necessary. We need to run them before the task is visible |
| 1217 | * on the tasklist. */ |
| 1218 | cgroup_fork_callbacks(p); |
| 1219 | cgroup_callbacks_done = 1; |
| 1220 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1221 | /* Need tasklist lock for parent etc handling! */ |
| 1222 | write_lock_irq(&tasklist_lock); |
| 1223 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1224 | /* CLONE_PARENT re-uses the old parent */ |
Oleg Nesterov | 2d5516c | 2009-03-02 22:58:45 +0100 | [diff] [blame] | 1225 | if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1226 | p->real_parent = current->real_parent; |
Oleg Nesterov | 2d5516c | 2009-03-02 22:58:45 +0100 | [diff] [blame] | 1227 | p->parent_exec_id = current->parent_exec_id; |
| 1228 | } else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1229 | p->real_parent = current; |
Oleg Nesterov | 2d5516c | 2009-03-02 22:58:45 +0100 | [diff] [blame] | 1230 | p->parent_exec_id = current->self_exec_id; |
| 1231 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1232 | |
Oleg Nesterov | 3f17da6 | 2006-02-15 22:13:24 +0300 | [diff] [blame] | 1233 | spin_lock(¤t->sighand->siglock); |
Oleg Nesterov | 4a2c7a7 | 2006-03-28 16:11:26 -0800 | [diff] [blame] | 1234 | |
| 1235 | /* |
| 1236 | * Process group and session signals need to be delivered to just the |
| 1237 | * parent before the fork or both the parent and the child after the |
| 1238 | * fork. Restart if a signal comes in before we add the new process to |
| 1239 | * it's process group. |
| 1240 | * A fatal signal pending means that current will exit, so the new |
| 1241 | * thread can't slip out of an OOM kill (or normal SIGKILL). |
| 1242 | */ |
Daniel Walker | 23ff444 | 2007-10-18 03:06:07 -0700 | [diff] [blame] | 1243 | recalc_sigpending(); |
Oleg Nesterov | 4a2c7a7 | 2006-03-28 16:11:26 -0800 | [diff] [blame] | 1244 | if (signal_pending(current)) { |
| 1245 | spin_unlock(¤t->sighand->siglock); |
| 1246 | write_unlock_irq(&tasklist_lock); |
| 1247 | retval = -ERESTARTNOINTR; |
Steven Rostedt | f7e8b61 | 2009-06-02 16:39:48 -0400 | [diff] [blame] | 1248 | goto bad_fork_free_pid; |
Oleg Nesterov | 4a2c7a7 | 2006-03-28 16:11:26 -0800 | [diff] [blame] | 1249 | } |
| 1250 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1251 | if (clone_flags & CLONE_THREAD) { |
Oleg Nesterov | 4ab6c08 | 2009-08-26 14:29:24 -0700 | [diff] [blame] | 1252 | atomic_inc(¤t->signal->count); |
| 1253 | atomic_inc(¤t->signal->live); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1254 | p->group_leader = current->group_leader; |
Oleg Nesterov | 47e6532 | 2006-03-28 16:11:25 -0800 | [diff] [blame] | 1255 | list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1256 | } |
| 1257 | |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1258 | if (likely(p->pid)) { |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 1259 | tracehook_finish_clone(p, clone_flags, trace); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1260 | |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1261 | if (thread_group_leader(p)) { |
Eric W. Biederman | 5cd1756 | 2007-12-04 23:45:04 -0800 | [diff] [blame] | 1262 | if (clone_flags & CLONE_NEWPID) |
Pavel Emelyanov | 30e49c2 | 2007-10-18 23:40:10 -0700 | [diff] [blame] | 1263 | p->nsproxy->pid_ns->child_reaper = p; |
Oleg Nesterov | c97d989 | 2006-03-28 16:11:06 -0800 | [diff] [blame] | 1264 | |
Oleg Nesterov | fea9d17 | 2008-02-08 04:19:19 -0800 | [diff] [blame] | 1265 | p->signal->leader_pid = pid; |
Alan Cox | 9c9f4de | 2008-10-13 10:37:26 +0100 | [diff] [blame] | 1266 | tty_kref_put(p->signal->tty); |
| 1267 | p->signal->tty = tty_kref_get(current->signal->tty); |
Eric W. Biederman | 5cd1756 | 2007-12-04 23:45:04 -0800 | [diff] [blame] | 1268 | attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); |
| 1269 | attach_pid(p, PIDTYPE_SID, task_session(current)); |
Oleg Nesterov | 9cd80bb | 2009-12-17 15:27:15 -0800 | [diff] [blame] | 1270 | list_add_tail(&p->sibling, &p->real_parent->children); |
Eric W. Biederman | 5e85d4a | 2006-04-18 22:20:16 -0700 | [diff] [blame] | 1271 | list_add_tail_rcu(&p->tasks, &init_task.tasks); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1272 | __get_cpu_var(process_counts)++; |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1273 | } |
Sukadev Bhattiprolu | 8586899 | 2007-05-10 22:23:03 -0700 | [diff] [blame] | 1274 | attach_pid(p, PIDTYPE_PID, pid); |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1275 | nr_threads++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1276 | } |
| 1277 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1278 | total_forks++; |
Oleg Nesterov | 3f17da6 | 2006-02-15 22:13:24 +0300 | [diff] [blame] | 1279 | spin_unlock(¤t->sighand->siglock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1280 | write_unlock_irq(&tasklist_lock); |
Andrew Morton | c13cf85 | 2005-11-28 13:43:48 -0800 | [diff] [blame] | 1281 | proc_fork_connector(p); |
Paul Menage | 817929e | 2007-10-18 23:39:36 -0700 | [diff] [blame] | 1282 | cgroup_post_fork(p); |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1283 | perf_event_fork(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1284 | return p; |
| 1285 | |
Pavel Emelyanov | 425fb2b | 2007-10-18 23:40:07 -0700 | [diff] [blame] | 1286 | bad_fork_free_pid: |
| 1287 | if (pid != &init_struct_pid) |
| 1288 | free_pid(pid); |
Jens Axboe | fd0928d | 2008-01-24 08:52:45 +0100 | [diff] [blame] | 1289 | bad_fork_cleanup_io: |
Louis Rilling | b69f229 | 2009-12-04 14:52:42 +0100 | [diff] [blame] | 1290 | if (p->io_context) |
| 1291 | exit_io_context(p); |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 1292 | bad_fork_cleanup_namespaces: |
Linus Torvalds | 444f378 | 2007-01-30 13:35:18 -0800 | [diff] [blame] | 1293 | exit_task_namespaces(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1294 | bad_fork_cleanup_mm: |
| 1295 | if (p->mm) |
| 1296 | mmput(p->mm); |
| 1297 | bad_fork_cleanup_signal: |
Oleg Nesterov | 4ab6c08 | 2009-08-26 14:29:24 -0700 | [diff] [blame] | 1298 | if (!(clone_flags & CLONE_THREAD)) |
| 1299 | __cleanup_signal(p->signal); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1300 | bad_fork_cleanup_sighand: |
Oleg Nesterov | a7e5328 | 2006-03-28 16:11:27 -0800 | [diff] [blame] | 1301 | __cleanup_sighand(p->sighand); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1302 | bad_fork_cleanup_fs: |
| 1303 | exit_fs(p); /* blocking */ |
| 1304 | bad_fork_cleanup_files: |
| 1305 | exit_files(p); /* blocking */ |
| 1306 | bad_fork_cleanup_semundo: |
| 1307 | exit_sem(p); |
| 1308 | bad_fork_cleanup_audit: |
| 1309 | audit_free(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1310 | bad_fork_cleanup_policy: |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1311 | perf_event_free_task(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1312 | #ifdef CONFIG_NUMA |
Lee Schermerhorn | f0be3d3 | 2008-04-28 02:13:08 -0700 | [diff] [blame] | 1313 | mpol_put(p->mempolicy); |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 1314 | bad_fork_cleanup_cgroup: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1315 | #endif |
Paul Menage | b4f48b6 | 2007-10-18 23:39:33 -0700 | [diff] [blame] | 1316 | cgroup_exit(p, cgroup_callbacks_done); |
Shailabh Nagar | 35df17c | 2006-08-31 21:27:38 -0700 | [diff] [blame] | 1317 | delayacct_tsk_free(p); |
Al Viro | a1261f5 | 2005-11-13 16:06:55 -0800 | [diff] [blame] | 1318 | module_put(task_thread_info(p)->exec_domain->module); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1319 | bad_fork_cleanup_count: |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 1320 | atomic_dec(&p->cred->user->processes); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 1321 | exit_creds(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1322 | bad_fork_free: |
| 1323 | free_task(p); |
Oleg Nesterov | fe7d37d | 2006-01-08 01:04:02 -0800 | [diff] [blame] | 1324 | fork_out: |
| 1325 | return ERR_PTR(retval); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1326 | } |
| 1327 | |
Adrian Bunk | 6b2fb3c | 2008-02-06 01:37:55 -0800 | [diff] [blame] | 1328 | noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1329 | { |
| 1330 | memset(regs, 0, sizeof(struct pt_regs)); |
| 1331 | return regs; |
| 1332 | } |
| 1333 | |
Al Viro | 9abcf40 | 2007-02-01 13:52:48 +0000 | [diff] [blame] | 1334 | struct task_struct * __cpuinit fork_idle(int cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1335 | { |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1336 | struct task_struct *task; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1337 | struct pt_regs regs; |
| 1338 | |
Pavel Emelyanov | 30e49c2 | 2007-10-18 23:40:10 -0700 | [diff] [blame] | 1339 | task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 1340 | &init_struct_pid, 0); |
Akinobu Mita | 753ca4f | 2006-11-25 11:09:34 -0800 | [diff] [blame] | 1341 | if (!IS_ERR(task)) |
| 1342 | init_idle(task, cpu); |
Oleg Nesterov | 73b9ebf | 2006-03-28 16:11:07 -0800 | [diff] [blame] | 1343 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1344 | return task; |
| 1345 | } |
| 1346 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1347 | /* |
| 1348 | * Ok, this is the main fork-routine. |
| 1349 | * |
| 1350 | * It copies the process, and if successful kick-starts |
| 1351 | * it and waits for it to finish using the VM if required. |
| 1352 | */ |
| 1353 | long do_fork(unsigned long clone_flags, |
| 1354 | unsigned long stack_start, |
| 1355 | struct pt_regs *regs, |
| 1356 | unsigned long stack_size, |
| 1357 | int __user *parent_tidptr, |
| 1358 | int __user *child_tidptr) |
| 1359 | { |
| 1360 | struct task_struct *p; |
| 1361 | int trace = 0; |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1362 | long nr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1363 | |
Andrew Morton | bdff746 | 2008-02-04 22:27:22 -0800 | [diff] [blame] | 1364 | /* |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 1365 | * Do some preliminary argument and permissions checking before we |
| 1366 | * actually start allocating stuff |
| 1367 | */ |
| 1368 | if (clone_flags & CLONE_NEWUSER) { |
| 1369 | if (clone_flags & CLONE_THREAD) |
| 1370 | return -EINVAL; |
| 1371 | /* hopefully this check will go away when userns support is |
| 1372 | * complete |
| 1373 | */ |
Serge E. Hallyn | 7657d90 | 2008-12-03 13:17:33 -0600 | [diff] [blame] | 1374 | if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) || |
| 1375 | !capable(CAP_SETGID)) |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 1376 | return -EPERM; |
| 1377 | } |
| 1378 | |
| 1379 | /* |
Andrew Morton | bdff746 | 2008-02-04 22:27:22 -0800 | [diff] [blame] | 1380 | * We hope to recycle these flags after 2.6.26 |
| 1381 | */ |
| 1382 | if (unlikely(clone_flags & CLONE_STOPPED)) { |
| 1383 | static int __read_mostly count = 100; |
| 1384 | |
| 1385 | if (count > 0 && printk_ratelimit()) { |
| 1386 | char comm[TASK_COMM_LEN]; |
| 1387 | |
| 1388 | count--; |
| 1389 | printk(KERN_INFO "fork(): process `%s' used deprecated " |
| 1390 | "clone flags 0x%lx\n", |
| 1391 | get_task_comm(comm, current), |
| 1392 | clone_flags & CLONE_STOPPED); |
| 1393 | } |
| 1394 | } |
| 1395 | |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 1396 | /* |
| 1397 | * When called from kernel_thread, don't do user tracing stuff. |
| 1398 | */ |
| 1399 | if (likely(user_mode(regs))) |
| 1400 | trace = tracehook_prepare_clone(clone_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1401 | |
Sukadev Bhattiprolu | a6f5e06 | 2007-10-18 23:39:53 -0700 | [diff] [blame] | 1402 | p = copy_process(clone_flags, stack_start, regs, stack_size, |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 1403 | child_tidptr, NULL, trace); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1404 | /* |
| 1405 | * Do this prior waking up the new thread - the thread pointer |
| 1406 | * might get invalid after that point, if the thread exits quickly. |
| 1407 | */ |
| 1408 | if (!IS_ERR(p)) { |
| 1409 | struct completion vfork; |
| 1410 | |
Mathieu Desnoyers | 0a16b60 | 2008-07-18 12:16:17 -0400 | [diff] [blame] | 1411 | trace_sched_process_fork(current, p); |
| 1412 | |
Pavel Emelyanov | 6c5f3e7 | 2008-02-08 04:19:20 -0800 | [diff] [blame] | 1413 | nr = task_pid_vnr(p); |
Pavel Emelyanov | 30e49c2 | 2007-10-18 23:40:10 -0700 | [diff] [blame] | 1414 | |
| 1415 | if (clone_flags & CLONE_PARENT_SETTID) |
| 1416 | put_user(nr, parent_tidptr); |
Sukadev Bhattiprolu | a6f5e06 | 2007-10-18 23:39:53 -0700 | [diff] [blame] | 1417 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1418 | if (clone_flags & CLONE_VFORK) { |
| 1419 | p->vfork_done = &vfork; |
| 1420 | init_completion(&vfork); |
| 1421 | } |
| 1422 | |
Al Viro | a64e649 | 2008-11-12 18:37:41 -0500 | [diff] [blame] | 1423 | audit_finish_fork(p); |
Oleg Nesterov | 087eb43 | 2009-06-04 16:29:07 -0700 | [diff] [blame] | 1424 | tracehook_report_clone(regs, clone_flags, nr, p); |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 1425 | |
| 1426 | /* |
| 1427 | * We set PF_STARTING at creation in case tracing wants to |
| 1428 | * use this to distinguish a fully live task from one that |
| 1429 | * hasn't gotten to tracehook_report_clone() yet. Now we |
| 1430 | * clear it and set the child going. |
| 1431 | */ |
| 1432 | p->flags &= ~PF_STARTING; |
| 1433 | |
| 1434 | if (unlikely(clone_flags & CLONE_STOPPED)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1435 | /* |
| 1436 | * We'll start up with an immediate SIGSTOP. |
| 1437 | */ |
| 1438 | sigaddset(&p->pending.signal, SIGSTOP); |
| 1439 | set_tsk_thread_flag(p, TIF_SIGPENDING); |
Oleg Nesterov | d9ae90a | 2008-02-06 01:36:13 -0800 | [diff] [blame] | 1440 | __set_task_state(p, TASK_STOPPED); |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 1441 | } else { |
| 1442 | wake_up_new_task(p, clone_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1443 | } |
| 1444 | |
Roland McGrath | 09a0539 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 1445 | tracehook_report_clone_complete(trace, regs, |
| 1446 | clone_flags, nr, p); |
| 1447 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1448 | if (clone_flags & CLONE_VFORK) { |
Rafael J. Wysocki | ba96a0c | 2007-05-23 13:57:25 -0700 | [diff] [blame] | 1449 | freezer_do_not_count(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1450 | wait_for_completion(&vfork); |
Rafael J. Wysocki | ba96a0c | 2007-05-23 13:57:25 -0700 | [diff] [blame] | 1451 | freezer_count(); |
Roland McGrath | daded34 | 2008-07-25 19:45:47 -0700 | [diff] [blame] | 1452 | tracehook_report_vfork_done(p, nr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1453 | } |
| 1454 | } else { |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1455 | nr = PTR_ERR(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1456 | } |
Eric W. Biederman | 92476d7 | 2006-03-31 02:31:42 -0800 | [diff] [blame] | 1457 | return nr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1458 | } |
| 1459 | |
Ravikiran G Thirumalai | 5fd63b3 | 2006-01-11 22:46:15 +0100 | [diff] [blame] | 1460 | #ifndef ARCH_MIN_MMSTRUCT_ALIGN |
| 1461 | #define ARCH_MIN_MMSTRUCT_ALIGN 0 |
| 1462 | #endif |
| 1463 | |
Alexey Dobriyan | 51cc506 | 2008-07-25 19:45:34 -0700 | [diff] [blame] | 1464 | static void sighand_ctor(void *data) |
Oleg Nesterov | aa1757f | 2006-03-28 16:11:12 -0800 | [diff] [blame] | 1465 | { |
| 1466 | struct sighand_struct *sighand = data; |
| 1467 | |
Christoph Lameter | a35afb8 | 2007-05-16 22:10:57 -0700 | [diff] [blame] | 1468 | spin_lock_init(&sighand->siglock); |
Davide Libenzi | b8fceee | 2007-09-20 12:40:16 -0700 | [diff] [blame] | 1469 | init_waitqueue_head(&sighand->signalfd_wqh); |
Oleg Nesterov | aa1757f | 2006-03-28 16:11:12 -0800 | [diff] [blame] | 1470 | } |
| 1471 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1472 | void __init proc_caches_init(void) |
| 1473 | { |
| 1474 | sighand_cachep = kmem_cache_create("sighand_cache", |
| 1475 | sizeof(struct sighand_struct), 0, |
Vegard Nossum | 2dff440 | 2008-05-31 15:56:17 +0200 | [diff] [blame] | 1476 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU| |
| 1477 | SLAB_NOTRACK, sighand_ctor); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1478 | signal_cachep = kmem_cache_create("signal_cache", |
| 1479 | sizeof(struct signal_struct), 0, |
Vegard Nossum | 2dff440 | 2008-05-31 15:56:17 +0200 | [diff] [blame] | 1480 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 1481 | files_cachep = kmem_cache_create("files_cache", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1482 | sizeof(struct files_struct), 0, |
Vegard Nossum | 2dff440 | 2008-05-31 15:56:17 +0200 | [diff] [blame] | 1483 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 1484 | fs_cachep = kmem_cache_create("fs_cache", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1485 | sizeof(struct fs_struct), 0, |
Vegard Nossum | 2dff440 | 2008-05-31 15:56:17 +0200 | [diff] [blame] | 1486 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1487 | mm_cachep = kmem_cache_create("mm_struct", |
Ravikiran G Thirumalai | 5fd63b3 | 2006-01-11 22:46:15 +0100 | [diff] [blame] | 1488 | sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN, |
Vegard Nossum | 2dff440 | 2008-05-31 15:56:17 +0200 | [diff] [blame] | 1489 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL); |
David Howells | 33e5d769 | 2009-04-02 16:56:32 -0700 | [diff] [blame] | 1490 | vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC); |
David Howells | 8feae13 | 2009-01-08 12:04:47 +0000 | [diff] [blame] | 1491 | mmap_init(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1492 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1493 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1494 | /* |
| 1495 | * Check constraints on flags passed to the unshare system call and |
| 1496 | * force unsharing of additional process context as appropriate. |
| 1497 | */ |
Alexey Dobriyan | a39bc51 | 2007-10-18 23:41:10 -0700 | [diff] [blame] | 1498 | static void check_unshare_flags(unsigned long *flags_ptr) |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1499 | { |
| 1500 | /* |
| 1501 | * If unsharing a thread from a thread group, must also |
| 1502 | * unshare vm. |
| 1503 | */ |
| 1504 | if (*flags_ptr & CLONE_THREAD) |
| 1505 | *flags_ptr |= CLONE_VM; |
| 1506 | |
| 1507 | /* |
| 1508 | * If unsharing vm, must also unshare signal handlers. |
| 1509 | */ |
| 1510 | if (*flags_ptr & CLONE_VM) |
| 1511 | *flags_ptr |= CLONE_SIGHAND; |
| 1512 | |
| 1513 | /* |
| 1514 | * If unsharing signal handlers and the task was created |
| 1515 | * using CLONE_THREAD, then must unshare the thread |
| 1516 | */ |
| 1517 | if ((*flags_ptr & CLONE_SIGHAND) && |
| 1518 | (atomic_read(¤t->signal->count) > 1)) |
| 1519 | *flags_ptr |= CLONE_THREAD; |
| 1520 | |
| 1521 | /* |
| 1522 | * If unsharing namespace, must also unshare filesystem information. |
| 1523 | */ |
| 1524 | if (*flags_ptr & CLONE_NEWNS) |
| 1525 | *flags_ptr |= CLONE_FS; |
| 1526 | } |
| 1527 | |
| 1528 | /* |
| 1529 | * Unsharing of tasks created with CLONE_THREAD is not supported yet |
| 1530 | */ |
| 1531 | static int unshare_thread(unsigned long unshare_flags) |
| 1532 | { |
| 1533 | if (unshare_flags & CLONE_THREAD) |
| 1534 | return -EINVAL; |
| 1535 | |
| 1536 | return 0; |
| 1537 | } |
| 1538 | |
| 1539 | /* |
JANAK DESAI | 99d1419 | 2006-02-07 12:58:59 -0800 | [diff] [blame] | 1540 | * Unshare the filesystem structure if it is being shared |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1541 | */ |
| 1542 | static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp) |
| 1543 | { |
| 1544 | struct fs_struct *fs = current->fs; |
| 1545 | |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1546 | if (!(unshare_flags & CLONE_FS) || !fs) |
| 1547 | return 0; |
| 1548 | |
| 1549 | /* don't need lock here; in the worst case we'll do useless copy */ |
| 1550 | if (fs->users == 1) |
| 1551 | return 0; |
| 1552 | |
| 1553 | *new_fsp = copy_fs_struct(fs); |
| 1554 | if (!*new_fsp) |
| 1555 | return -ENOMEM; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1556 | |
| 1557 | return 0; |
| 1558 | } |
| 1559 | |
| 1560 | /* |
Oleg Nesterov | dae3c5a | 2006-12-08 02:36:09 -0800 | [diff] [blame] | 1561 | * Unsharing of sighand is not supported yet |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1562 | */ |
| 1563 | static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp) |
| 1564 | { |
| 1565 | struct sighand_struct *sigh = current->sighand; |
| 1566 | |
Oleg Nesterov | dae3c5a | 2006-12-08 02:36:09 -0800 | [diff] [blame] | 1567 | if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1) |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1568 | return -EINVAL; |
| 1569 | else |
| 1570 | return 0; |
| 1571 | } |
| 1572 | |
| 1573 | /* |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 1574 | * Unshare vm if it is being shared |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1575 | */ |
| 1576 | static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp) |
| 1577 | { |
| 1578 | struct mm_struct *mm = current->mm; |
| 1579 | |
| 1580 | if ((unshare_flags & CLONE_VM) && |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 1581 | (mm && atomic_read(&mm->mm_users) > 1)) { |
Oleg Nesterov | 2d61b86 | 2006-03-18 20:41:10 +0300 | [diff] [blame] | 1582 | return -EINVAL; |
JANAK DESAI | a0a7ec3 | 2006-02-07 12:59:01 -0800 | [diff] [blame] | 1583 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1584 | |
| 1585 | return 0; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1586 | } |
| 1587 | |
| 1588 | /* |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 1589 | * Unshare file descriptor table if it is being shared |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1590 | */ |
| 1591 | static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp) |
| 1592 | { |
| 1593 | struct files_struct *fd = current->files; |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 1594 | int error = 0; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1595 | |
| 1596 | if ((unshare_flags & CLONE_FILES) && |
JANAK DESAI | a016f33 | 2006-02-07 12:59:02 -0800 | [diff] [blame] | 1597 | (fd && atomic_read(&fd->count) > 1)) { |
| 1598 | *new_fdp = dup_fd(fd, &error); |
| 1599 | if (!*new_fdp) |
| 1600 | return error; |
| 1601 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1602 | |
| 1603 | return 0; |
| 1604 | } |
| 1605 | |
| 1606 | /* |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1607 | * unshare allows a process to 'unshare' part of the process |
| 1608 | * context which was originally shared using clone. copy_* |
| 1609 | * functions used by do_fork() cannot be used here directly |
| 1610 | * because they modify an inactive task_struct that is being |
| 1611 | * constructed. Here we are modifying the current, active, |
| 1612 | * task_struct. |
| 1613 | */ |
Heiko Carstens | 6559eed8 | 2009-01-14 14:14:32 +0100 | [diff] [blame] | 1614 | SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1615 | { |
| 1616 | int err = 0; |
| 1617 | struct fs_struct *fs, *new_fs = NULL; |
Oleg Nesterov | dae3c5a | 2006-12-08 02:36:09 -0800 | [diff] [blame] | 1618 | struct sighand_struct *new_sigh = NULL; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1619 | struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL; |
| 1620 | struct files_struct *fd, *new_fd = NULL; |
Pavel Emelyanov | cf7b708 | 2007-10-18 23:39:54 -0700 | [diff] [blame] | 1621 | struct nsproxy *new_nsproxy = NULL; |
Manfred Spraul | 9edff4a | 2008-04-29 01:00:57 -0700 | [diff] [blame] | 1622 | int do_sysvsem = 0; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1623 | |
| 1624 | check_unshare_flags(&unshare_flags); |
| 1625 | |
Eric W. Biederman | 06f9d4f | 2006-03-22 00:07:40 -0800 | [diff] [blame] | 1626 | /* Return -EINVAL for all unsupported flags */ |
| 1627 | err = -EINVAL; |
| 1628 | if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND| |
Kirill Korotaev | 25b21cb | 2006-10-02 02:18:19 -0700 | [diff] [blame] | 1629 | CLONE_VM|CLONE_FILES|CLONE_SYSVSEM| |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 1630 | CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET)) |
Eric W. Biederman | 06f9d4f | 2006-03-22 00:07:40 -0800 | [diff] [blame] | 1631 | goto bad_unshare_out; |
| 1632 | |
Manfred Spraul | 6013f67 | 2008-04-29 01:00:59 -0700 | [diff] [blame] | 1633 | /* |
| 1634 | * CLONE_NEWIPC must also detach from the undolist: after switching |
| 1635 | * to a new ipc namespace, the semaphore arrays from the old |
| 1636 | * namespace are unreachable. |
| 1637 | */ |
| 1638 | if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM)) |
Manfred Spraul | 9edff4a | 2008-04-29 01:00:57 -0700 | [diff] [blame] | 1639 | do_sysvsem = 1; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1640 | if ((err = unshare_thread(unshare_flags))) |
| 1641 | goto bad_unshare_out; |
| 1642 | if ((err = unshare_fs(unshare_flags, &new_fs))) |
| 1643 | goto bad_unshare_cleanup_thread; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1644 | if ((err = unshare_sighand(unshare_flags, &new_sigh))) |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 1645 | goto bad_unshare_cleanup_fs; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1646 | if ((err = unshare_vm(unshare_flags, &new_mm))) |
| 1647 | goto bad_unshare_cleanup_sigh; |
| 1648 | if ((err = unshare_fd(unshare_flags, &new_fd))) |
| 1649 | goto bad_unshare_cleanup_vm; |
Badari Pulavarty | e3222c4 | 2007-05-08 00:25:21 -0700 | [diff] [blame] | 1650 | if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy, |
| 1651 | new_fs))) |
Manfred Spraul | 9edff4a | 2008-04-29 01:00:57 -0700 | [diff] [blame] | 1652 | goto bad_unshare_cleanup_fd; |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1653 | |
Manfred Spraul | 9edff4a | 2008-04-29 01:00:57 -0700 | [diff] [blame] | 1654 | if (new_fs || new_mm || new_fd || do_sysvsem || new_nsproxy) { |
| 1655 | if (do_sysvsem) { |
| 1656 | /* |
| 1657 | * CLONE_SYSVSEM is equivalent to sys_exit(). |
| 1658 | */ |
| 1659 | exit_sem(current); |
| 1660 | } |
Serge E. Hallyn | ab51601 | 2006-10-02 02:18:06 -0700 | [diff] [blame] | 1661 | |
Serge Hallyn | c0b2fc3 | 2006-10-02 02:18:18 -0700 | [diff] [blame] | 1662 | if (new_nsproxy) { |
Pavel Emelyanov | cf7b708 | 2007-10-18 23:39:54 -0700 | [diff] [blame] | 1663 | switch_task_namespaces(current, new_nsproxy); |
| 1664 | new_nsproxy = NULL; |
Serge Hallyn | c0b2fc3 | 2006-10-02 02:18:18 -0700 | [diff] [blame] | 1665 | } |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1666 | |
Pavel Emelyanov | cf7b708 | 2007-10-18 23:39:54 -0700 | [diff] [blame] | 1667 | task_lock(current); |
| 1668 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1669 | if (new_fs) { |
| 1670 | fs = current->fs; |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1671 | write_lock(&fs->lock); |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1672 | current->fs = new_fs; |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1673 | if (--fs->users) |
| 1674 | new_fs = NULL; |
| 1675 | else |
| 1676 | new_fs = fs; |
| 1677 | write_unlock(&fs->lock); |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1678 | } |
| 1679 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1680 | if (new_mm) { |
| 1681 | mm = current->mm; |
| 1682 | active_mm = current->active_mm; |
| 1683 | current->mm = new_mm; |
| 1684 | current->active_mm = new_mm; |
| 1685 | activate_mm(active_mm, new_mm); |
| 1686 | new_mm = mm; |
| 1687 | } |
| 1688 | |
| 1689 | if (new_fd) { |
| 1690 | fd = current->files; |
| 1691 | current->files = new_fd; |
| 1692 | new_fd = fd; |
| 1693 | } |
| 1694 | |
| 1695 | task_unlock(current); |
| 1696 | } |
| 1697 | |
Serge Hallyn | c0b2fc3 | 2006-10-02 02:18:18 -0700 | [diff] [blame] | 1698 | if (new_nsproxy) |
Linus Torvalds | 444f378 | 2007-01-30 13:35:18 -0800 | [diff] [blame] | 1699 | put_nsproxy(new_nsproxy); |
Serge Hallyn | c0b2fc3 | 2006-10-02 02:18:18 -0700 | [diff] [blame] | 1700 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1701 | bad_unshare_cleanup_fd: |
| 1702 | if (new_fd) |
| 1703 | put_files_struct(new_fd); |
| 1704 | |
| 1705 | bad_unshare_cleanup_vm: |
| 1706 | if (new_mm) |
| 1707 | mmput(new_mm); |
| 1708 | |
| 1709 | bad_unshare_cleanup_sigh: |
| 1710 | if (new_sigh) |
| 1711 | if (atomic_dec_and_test(&new_sigh->count)) |
| 1712 | kmem_cache_free(sighand_cachep, new_sigh); |
| 1713 | |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1714 | bad_unshare_cleanup_fs: |
| 1715 | if (new_fs) |
Al Viro | 498052b | 2009-03-30 07:20:30 -0400 | [diff] [blame] | 1716 | free_fs_struct(new_fs); |
JANAK DESAI | cf2e340 | 2006-02-07 12:58:58 -0800 | [diff] [blame] | 1717 | |
| 1718 | bad_unshare_cleanup_thread: |
| 1719 | bad_unshare_out: |
| 1720 | return err; |
| 1721 | } |
Al Viro | 3b12538 | 2008-04-22 05:31:30 -0400 | [diff] [blame] | 1722 | |
| 1723 | /* |
| 1724 | * Helper to unshare the files of the current task. |
| 1725 | * We don't want to expose copy_files internals to |
| 1726 | * the exec layer of the kernel. |
| 1727 | */ |
| 1728 | |
| 1729 | int unshare_files(struct files_struct **displaced) |
| 1730 | { |
| 1731 | struct task_struct *task = current; |
Al Viro | 5070451 | 2008-04-26 05:25:00 +0100 | [diff] [blame] | 1732 | struct files_struct *copy = NULL; |
Al Viro | 3b12538 | 2008-04-22 05:31:30 -0400 | [diff] [blame] | 1733 | int error; |
| 1734 | |
| 1735 | error = unshare_fd(CLONE_FILES, ©); |
| 1736 | if (error || !copy) { |
| 1737 | *displaced = NULL; |
| 1738 | return error; |
| 1739 | } |
| 1740 | *displaced = task->files; |
| 1741 | task_lock(task); |
| 1742 | task->files = copy; |
| 1743 | task_unlock(task); |
| 1744 | return 0; |
| 1745 | } |