Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/kernel/exit.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | */ | |
7 | ||
1da177e4 LT |
8 | #include <linux/mm.h> |
9 | #include <linux/slab.h> | |
4eb5aaa3 | 10 | #include <linux/sched/autogroup.h> |
6e84f315 | 11 | #include <linux/sched/mm.h> |
03441a34 | 12 | #include <linux/sched/stat.h> |
29930025 | 13 | #include <linux/sched/task.h> |
68db0cf1 | 14 | #include <linux/sched/task_stack.h> |
32ef5517 | 15 | #include <linux/sched/cputime.h> |
1da177e4 | 16 | #include <linux/interrupt.h> |
1da177e4 | 17 | #include <linux/module.h> |
c59ede7b | 18 | #include <linux/capability.h> |
1da177e4 LT |
19 | #include <linux/completion.h> |
20 | #include <linux/personality.h> | |
21 | #include <linux/tty.h> | |
da9cbc87 | 22 | #include <linux/iocontext.h> |
1da177e4 | 23 | #include <linux/key.h> |
1da177e4 LT |
24 | #include <linux/cpu.h> |
25 | #include <linux/acct.h> | |
8f0ab514 | 26 | #include <linux/tsacct_kern.h> |
1da177e4 | 27 | #include <linux/file.h> |
9f3acc31 | 28 | #include <linux/fdtable.h> |
80d26af8 | 29 | #include <linux/freezer.h> |
1da177e4 | 30 | #include <linux/binfmts.h> |
ab516013 | 31 | #include <linux/nsproxy.h> |
84d73786 | 32 | #include <linux/pid_namespace.h> |
1da177e4 LT |
33 | #include <linux/ptrace.h> |
34 | #include <linux/profile.h> | |
35 | #include <linux/mount.h> | |
36 | #include <linux/proc_fs.h> | |
49d769d5 | 37 | #include <linux/kthread.h> |
1da177e4 | 38 | #include <linux/mempolicy.h> |
c757249a | 39 | #include <linux/taskstats_kern.h> |
ca74e92b | 40 | #include <linux/delayacct.h> |
b4f48b63 | 41 | #include <linux/cgroup.h> |
1da177e4 | 42 | #include <linux/syscalls.h> |
7ed20e1a | 43 | #include <linux/signal.h> |
6a14c5c9 | 44 | #include <linux/posix-timers.h> |
9f46080c | 45 | #include <linux/cn_proc.h> |
de5097c2 | 46 | #include <linux/mutex.h> |
0771dfef | 47 | #include <linux/futex.h> |
b92ce558 | 48 | #include <linux/pipe_fs_i.h> |
fa84cb93 | 49 | #include <linux/audit.h> /* for audit_free() */ |
83cc5ed3 | 50 | #include <linux/resource.h> |
6eaeeaba | 51 | #include <linux/task_io_accounting_ops.h> |
355f841a EB |
52 | #include <linux/blkdev.h> |
53 | #include <linux/task_work.h> | |
5ad4e53b | 54 | #include <linux/fs_struct.h> |
d84f4f99 | 55 | #include <linux/init_task.h> |
cdd6c482 | 56 | #include <linux/perf_event.h> |
ad8d75ff | 57 | #include <trace/events/sched.h> |
24f1e32c | 58 | #include <linux/hw_breakpoint.h> |
3d5992d2 | 59 | #include <linux/oom.h> |
54848d73 | 60 | #include <linux/writeback.h> |
40401530 | 61 | #include <linux/shm.h> |
5c9a8750 | 62 | #include <linux/kcov.h> |
50b5e49c | 63 | #include <linux/kmsan.h> |
53d3eaa3 | 64 | #include <linux/random.h> |
8f95c90c | 65 | #include <linux/rcuwait.h> |
7e95a225 | 66 | #include <linux/compat.h> |
b1b6b5a3 | 67 | #include <linux/io_uring.h> |
670721c7 | 68 | #include <linux/kprobes.h> |
54ecbe6f | 69 | #include <linux/rethook.h> |
9db89b41 | 70 | #include <linux/sysfs.h> |
fd593511 | 71 | #include <linux/user_events.h> |
7c0f6ba6 | 72 | #include <linux/uaccess.h> |
6dfeff09 MWO |
73 | |
74 | #include <uapi/linux/wait.h> | |
75 | ||
1da177e4 | 76 | #include <asm/unistd.h> |
1da177e4 LT |
77 | #include <asm/mmu_context.h> |
78 | ||
2e521a20 JA |
79 | #include "exit.h" |
80 | ||
d4ccd54d JH |
81 | /* |
82 | * The default value should be high enough to not crash a system that randomly | |
83 | * crashes its kernel from time to time, but low enough to at least not permit | |
84 | * overflowing 32-bit refcounts or the ldsem writer count. | |
85 | */ | |
86 | static unsigned int oops_limit = 10000; | |
87 | ||
88 | #ifdef CONFIG_SYSCTL | |
89 | static struct ctl_table kern_exit_table[] = { | |
90 | { | |
91 | .procname = "oops_limit", | |
92 | .data = &oops_limit, | |
93 | .maxlen = sizeof(oops_limit), | |
94 | .mode = 0644, | |
95 | .proc_handler = proc_douintvec, | |
96 | }, | |
97 | { } | |
98 | }; | |
99 | ||
100 | static __init int kernel_exit_sysctls_init(void) | |
101 | { | |
102 | register_sysctl_init("kernel", kern_exit_table); | |
103 | return 0; | |
104 | } | |
105 | late_initcall(kernel_exit_sysctls_init); | |
106 | #endif | |
107 | ||
9db89b41 KC |
108 | static atomic_t oops_count = ATOMIC_INIT(0); |
109 | ||
110 | #ifdef CONFIG_SYSFS | |
111 | static ssize_t oops_count_show(struct kobject *kobj, struct kobj_attribute *attr, | |
112 | char *page) | |
113 | { | |
114 | return sysfs_emit(page, "%d\n", atomic_read(&oops_count)); | |
115 | } | |
116 | ||
117 | static struct kobj_attribute oops_count_attr = __ATTR_RO(oops_count); | |
118 | ||
119 | static __init int kernel_exit_sysfs_init(void) | |
120 | { | |
121 | sysfs_add_file_to_group(kernel_kobj, &oops_count_attr.attr, NULL); | |
122 | return 0; | |
123 | } | |
124 | late_initcall(kernel_exit_sysfs_init); | |
125 | #endif | |
126 | ||
d40e48e0 | 127 | static void __unhash_process(struct task_struct *p, bool group_dead) |
1da177e4 LT |
128 | { |
129 | nr_threads--; | |
50d75f8d | 130 | detach_pid(p, PIDTYPE_PID); |
d40e48e0 | 131 | if (group_dead) { |
6883f81a | 132 | detach_pid(p, PIDTYPE_TGID); |
1da177e4 LT |
133 | detach_pid(p, PIDTYPE_PGID); |
134 | detach_pid(p, PIDTYPE_SID); | |
c97d9893 | 135 | |
5e85d4ab | 136 | list_del_rcu(&p->tasks); |
9cd80bbb | 137 | list_del_init(&p->sibling); |
909ea964 | 138 | __this_cpu_dec(process_counts); |
1da177e4 | 139 | } |
0c740d0a | 140 | list_del_rcu(&p->thread_node); |
1da177e4 LT |
141 | } |
142 | ||
6a14c5c9 ON |
143 | /* |
144 | * This function expects the tasklist_lock write-locked. | |
145 | */ | |
146 | static void __exit_signal(struct task_struct *tsk) | |
147 | { | |
148 | struct signal_struct *sig = tsk->signal; | |
d40e48e0 | 149 | bool group_dead = thread_group_leader(tsk); |
6a14c5c9 | 150 | struct sighand_struct *sighand; |
3f649ab7 | 151 | struct tty_struct *tty; |
5613fda9 | 152 | u64 utime, stime; |
6a14c5c9 | 153 | |
d11c563d | 154 | sighand = rcu_dereference_check(tsk->sighand, |
db1466b3 | 155 | lockdep_tasklist_lock_is_held()); |
6a14c5c9 ON |
156 | spin_lock(&sighand->siglock); |
157 | ||
baa73d9e | 158 | #ifdef CONFIG_POSIX_TIMERS |
6a14c5c9 | 159 | posix_cpu_timers_exit(tsk); |
b95e31c0 | 160 | if (group_dead) |
6a14c5c9 | 161 | posix_cpu_timers_exit_group(tsk); |
baa73d9e | 162 | #endif |
e0a70217 | 163 | |
baa73d9e NP |
164 | if (group_dead) { |
165 | tty = sig->tty; | |
166 | sig->tty = NULL; | |
167 | } else { | |
6a14c5c9 ON |
168 | /* |
169 | * If there is any task waiting for the group exit | |
170 | * then notify it: | |
171 | */ | |
d344193a | 172 | if (sig->notify_count > 0 && !--sig->notify_count) |
60700e38 | 173 | wake_up_process(sig->group_exec_task); |
6db840fa | 174 | |
6a14c5c9 ON |
175 | if (tsk == sig->curr_target) |
176 | sig->curr_target = next_thread(tsk); | |
6a14c5c9 ON |
177 | } |
178 | ||
53d3eaa3 NP |
179 | add_device_randomness((const void*) &tsk->se.sum_exec_runtime, |
180 | sizeof(unsigned long long)); | |
181 | ||
90ed9cbe | 182 | /* |
26e75b5c ON |
183 | * Accumulate here the counters for all threads as they die. We could |
184 | * skip the group leader because it is the last user of signal_struct, | |
185 | * but we want to avoid the race with thread_group_cputime() which can | |
186 | * see the empty ->thread_head list. | |
90ed9cbe RR |
187 | */ |
188 | task_cputime(tsk, &utime, &stime); | |
e78c3496 | 189 | write_seqlock(&sig->stats_lock); |
90ed9cbe RR |
190 | sig->utime += utime; |
191 | sig->stime += stime; | |
192 | sig->gtime += task_gtime(tsk); | |
193 | sig->min_flt += tsk->min_flt; | |
194 | sig->maj_flt += tsk->maj_flt; | |
195 | sig->nvcsw += tsk->nvcsw; | |
196 | sig->nivcsw += tsk->nivcsw; | |
197 | sig->inblock += task_io_get_inblock(tsk); | |
198 | sig->oublock += task_io_get_oublock(tsk); | |
199 | task_io_accounting_add(&sig->ioac, &tsk->ioac); | |
200 | sig->sum_sched_runtime += tsk->se.sum_exec_runtime; | |
b3ac022c | 201 | sig->nr_threads--; |
d40e48e0 | 202 | __unhash_process(tsk, group_dead); |
e78c3496 | 203 | write_sequnlock(&sig->stats_lock); |
5876700c | 204 | |
da7978b0 ON |
205 | /* |
206 | * Do this under ->siglock, we can race with another thread | |
207 | * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals. | |
208 | */ | |
209 | flush_sigqueue(&tsk->pending); | |
a7e5328a | 210 | tsk->sighand = NULL; |
6a14c5c9 | 211 | spin_unlock(&sighand->siglock); |
6a14c5c9 | 212 | |
a7e5328a | 213 | __cleanup_sighand(sighand); |
a0be55de | 214 | clear_tsk_thread_flag(tsk, TIF_SIGPENDING); |
d40e48e0 | 215 | if (group_dead) { |
6a14c5c9 | 216 | flush_sigqueue(&sig->shared_pending); |
4ada856f | 217 | tty_kref_put(tty); |
6a14c5c9 ON |
218 | } |
219 | } | |
220 | ||
8c7904a0 EB |
221 | static void delayed_put_task_struct(struct rcu_head *rhp) |
222 | { | |
0a16b607 MD |
223 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); |
224 | ||
670721c7 | 225 | kprobe_flush_task(tsk); |
54ecbe6f | 226 | rethook_flush_task(tsk); |
4e231c79 | 227 | perf_event_delayed_put(tsk); |
0a16b607 MD |
228 | trace_sched_process_free(tsk); |
229 | put_task_struct(tsk); | |
8c7904a0 EB |
230 | } |
231 | ||
3fbd7ee2 EB |
232 | void put_task_struct_rcu_user(struct task_struct *task) |
233 | { | |
234 | if (refcount_dec_and_test(&task->rcu_users)) | |
235 | call_rcu(&task->rcu, delayed_put_task_struct); | |
236 | } | |
f470021a | 237 | |
2be9880d KW |
238 | void __weak release_thread(struct task_struct *dead_task) |
239 | { | |
240 | } | |
241 | ||
a0be55de | 242 | void release_task(struct task_struct *p) |
1da177e4 | 243 | { |
36c8b586 | 244 | struct task_struct *leader; |
7bc3e6e5 | 245 | struct pid *thread_pid; |
1da177e4 | 246 | int zap_leader; |
1f09f974 | 247 | repeat: |
c69e8d9c | 248 | /* don't need to get the RCU readlock here - the process is dead and |
d11c563d PM |
249 | * can't be modifying its own credentials. But shut RCU-lockdep up */ |
250 | rcu_read_lock(); | |
21d1c5e3 | 251 | dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1); |
d11c563d | 252 | rcu_read_unlock(); |
c69e8d9c | 253 | |
6b115bf5 | 254 | cgroup_release(p); |
0203026b | 255 | |
1da177e4 | 256 | write_lock_irq(&tasklist_lock); |
a288eecc | 257 | ptrace_release_task(p); |
7bc3e6e5 | 258 | thread_pid = get_pid(p->thread_pid); |
1da177e4 | 259 | __exit_signal(p); |
35f5cad8 | 260 | |
1da177e4 LT |
261 | /* |
262 | * If we are the last non-leader member of the thread | |
263 | * group, and the leader is zombie, then notify the | |
264 | * group leader's parent process. (if it wants notification.) | |
265 | */ | |
266 | zap_leader = 0; | |
267 | leader = p->group_leader; | |
a0be55de IA |
268 | if (leader != p && thread_group_empty(leader) |
269 | && leader->exit_state == EXIT_ZOMBIE) { | |
1da177e4 LT |
270 | /* |
271 | * If we were the last child thread and the leader has | |
272 | * exited already, and the leader's parent ignores SIGCHLD, | |
273 | * then we are the one who should release the leader. | |
dae33574 | 274 | */ |
86773473 | 275 | zap_leader = do_notify_parent(leader, leader->exit_signal); |
dae33574 RM |
276 | if (zap_leader) |
277 | leader->exit_state = EXIT_DEAD; | |
1da177e4 LT |
278 | } |
279 | ||
1da177e4 | 280 | write_unlock_irq(&tasklist_lock); |
3a15fb6e | 281 | seccomp_filter_release(p); |
7bc3e6e5 | 282 | proc_flush_pid(thread_pid); |
6ade99ec | 283 | put_pid(thread_pid); |
1da177e4 | 284 | release_thread(p); |
3fbd7ee2 | 285 | put_task_struct_rcu_user(p); |
1da177e4 LT |
286 | |
287 | p = leader; | |
288 | if (unlikely(zap_leader)) | |
289 | goto repeat; | |
290 | } | |
291 | ||
9d9a6ebf | 292 | int rcuwait_wake_up(struct rcuwait *w) |
8f95c90c | 293 | { |
9d9a6ebf | 294 | int ret = 0; |
8f95c90c DB |
295 | struct task_struct *task; |
296 | ||
297 | rcu_read_lock(); | |
298 | ||
299 | /* | |
300 | * Order condition vs @task, such that everything prior to the load | |
301 | * of @task is visible. This is the condition as to why the user called | |
c9d64a1b | 302 | * rcuwait_wake() in the first place. Pairs with set_current_state() |
8f95c90c DB |
303 | * barrier (A) in rcuwait_wait_event(). |
304 | * | |
305 | * WAIT WAKE | |
306 | * [S] tsk = current [S] cond = true | |
307 | * MB (A) MB (B) | |
308 | * [L] cond [L] tsk | |
309 | */ | |
6dc080ee | 310 | smp_mb(); /* (B) */ |
8f95c90c | 311 | |
8f95c90c DB |
312 | task = rcu_dereference(w->task); |
313 | if (task) | |
9d9a6ebf | 314 | ret = wake_up_process(task); |
8f95c90c | 315 | rcu_read_unlock(); |
9d9a6ebf DB |
316 | |
317 | return ret; | |
8f95c90c | 318 | } |
ac8dec42 | 319 | EXPORT_SYMBOL_GPL(rcuwait_wake_up); |
8f95c90c | 320 | |
1da177e4 LT |
321 | /* |
322 | * Determine if a process group is "orphaned", according to the POSIX | |
323 | * definition in 2.2.2.52. Orphaned process groups are not to be affected | |
324 | * by terminal-generated stop signals. Newly orphaned process groups are | |
325 | * to receive a SIGHUP and a SIGCONT. | |
326 | * | |
327 | * "I ask you, have you ever known what it is to be an orphan?" | |
328 | */ | |
a0be55de IA |
329 | static int will_become_orphaned_pgrp(struct pid *pgrp, |
330 | struct task_struct *ignored_task) | |
1da177e4 LT |
331 | { |
332 | struct task_struct *p; | |
1da177e4 | 333 | |
0475ac08 | 334 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
05e83df6 ON |
335 | if ((p == ignored_task) || |
336 | (p->exit_state && thread_group_empty(p)) || | |
337 | is_global_init(p->real_parent)) | |
1da177e4 | 338 | continue; |
05e83df6 | 339 | |
0475ac08 | 340 | if (task_pgrp(p->real_parent) != pgrp && |
05e83df6 ON |
341 | task_session(p->real_parent) == task_session(p)) |
342 | return 0; | |
0475ac08 | 343 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
05e83df6 ON |
344 | |
345 | return 1; | |
1da177e4 LT |
346 | } |
347 | ||
3e7cd6c4 | 348 | int is_current_pgrp_orphaned(void) |
1da177e4 LT |
349 | { |
350 | int retval; | |
351 | ||
352 | read_lock(&tasklist_lock); | |
3e7cd6c4 | 353 | retval = will_become_orphaned_pgrp(task_pgrp(current), NULL); |
1da177e4 LT |
354 | read_unlock(&tasklist_lock); |
355 | ||
356 | return retval; | |
357 | } | |
358 | ||
961c4675 | 359 | static bool has_stopped_jobs(struct pid *pgrp) |
1da177e4 | 360 | { |
1da177e4 LT |
361 | struct task_struct *p; |
362 | ||
0475ac08 | 363 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
961c4675 ON |
364 | if (p->signal->flags & SIGNAL_STOP_STOPPED) |
365 | return true; | |
0475ac08 | 366 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
961c4675 ON |
367 | |
368 | return false; | |
1da177e4 LT |
369 | } |
370 | ||
f49ee505 ON |
371 | /* |
372 | * Check to see if any process groups have become orphaned as | |
373 | * a result of our exiting, and if they have any stopped jobs, | |
374 | * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
375 | */ | |
376 | static void | |
377 | kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) | |
378 | { | |
379 | struct pid *pgrp = task_pgrp(tsk); | |
380 | struct task_struct *ignored_task = tsk; | |
381 | ||
382 | if (!parent) | |
a0be55de IA |
383 | /* exit: our father is in a different pgrp than |
384 | * we are and we were the only connection outside. | |
385 | */ | |
f49ee505 ON |
386 | parent = tsk->real_parent; |
387 | else | |
388 | /* reparent: our child is in a different pgrp than | |
389 | * we are, and it was the only connection outside. | |
390 | */ | |
391 | ignored_task = NULL; | |
392 | ||
393 | if (task_pgrp(parent) != pgrp && | |
394 | task_session(parent) == task_session(tsk) && | |
395 | will_become_orphaned_pgrp(pgrp, ignored_task) && | |
396 | has_stopped_jobs(pgrp)) { | |
397 | __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); | |
398 | __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); | |
399 | } | |
400 | } | |
401 | ||
92307383 | 402 | static void coredump_task_exit(struct task_struct *tsk) |
d67e03e3 EB |
403 | { |
404 | struct core_state *core_state; | |
405 | ||
406 | /* | |
407 | * Serialize with any possible pending coredump. | |
0258b5fd | 408 | * We must hold siglock around checking core_state |
92307383 | 409 | * and setting PF_POSTCOREDUMP. The core-inducing thread |
d67e03e3 | 410 | * will increment ->nr_threads for each thread in the |
92307383 | 411 | * group without PF_POSTCOREDUMP set. |
d67e03e3 | 412 | */ |
0258b5fd | 413 | spin_lock_irq(&tsk->sighand->siglock); |
92307383 | 414 | tsk->flags |= PF_POSTCOREDUMP; |
0258b5fd EB |
415 | core_state = tsk->signal->core_state; |
416 | spin_unlock_irq(&tsk->sighand->siglock); | |
f9010dbd MC |
417 | |
418 | /* The vhost_worker does not particpate in coredumps */ | |
419 | if (core_state && | |
420 | ((tsk->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)) { | |
d67e03e3 EB |
421 | struct core_thread self; |
422 | ||
d67e03e3 EB |
423 | self.task = current; |
424 | if (self.task->flags & PF_SIGNALED) | |
425 | self.next = xchg(&core_state->dumper.next, &self); | |
426 | else | |
427 | self.task = NULL; | |
428 | /* | |
429 | * Implies mb(), the result of xchg() must be visible | |
430 | * to core_state->dumper. | |
431 | */ | |
432 | if (atomic_dec_and_test(&core_state->nr_threads)) | |
433 | complete(&core_state->startup); | |
434 | ||
435 | for (;;) { | |
f5d39b02 | 436 | set_current_state(TASK_UNINTERRUPTIBLE|TASK_FREEZABLE); |
d67e03e3 EB |
437 | if (!self.task) /* see coredump_finish() */ |
438 | break; | |
f5d39b02 | 439 | schedule(); |
d67e03e3 EB |
440 | } |
441 | __set_current_state(TASK_RUNNING); | |
d67e03e3 EB |
442 | } |
443 | } | |
444 | ||
f98bafa0 | 445 | #ifdef CONFIG_MEMCG |
cf475ad2 | 446 | /* |
733eda7a | 447 | * A task is exiting. If it owned this mm, find a new owner for the mm. |
cf475ad2 | 448 | */ |
cf475ad2 BS |
449 | void mm_update_next_owner(struct mm_struct *mm) |
450 | { | |
451 | struct task_struct *c, *g, *p = current; | |
452 | ||
453 | retry: | |
733eda7a KH |
454 | /* |
455 | * If the exiting or execing task is not the owner, it's | |
456 | * someone else's problem. | |
457 | */ | |
458 | if (mm->owner != p) | |
cf475ad2 | 459 | return; |
733eda7a KH |
460 | /* |
461 | * The current owner is exiting/execing and there are no other | |
462 | * candidates. Do not leave the mm pointing to a possibly | |
463 | * freed task structure. | |
464 | */ | |
465 | if (atomic_read(&mm->mm_users) <= 1) { | |
987717e5 | 466 | WRITE_ONCE(mm->owner, NULL); |
733eda7a KH |
467 | return; |
468 | } | |
cf475ad2 BS |
469 | |
470 | read_lock(&tasklist_lock); | |
471 | /* | |
472 | * Search in the children | |
473 | */ | |
474 | list_for_each_entry(c, &p->children, sibling) { | |
475 | if (c->mm == mm) | |
476 | goto assign_new_owner; | |
477 | } | |
478 | ||
479 | /* | |
480 | * Search in the siblings | |
481 | */ | |
dea33cfd | 482 | list_for_each_entry(c, &p->real_parent->children, sibling) { |
cf475ad2 BS |
483 | if (c->mm == mm) |
484 | goto assign_new_owner; | |
485 | } | |
486 | ||
487 | /* | |
f87fb599 | 488 | * Search through everything else, we should not get here often. |
cf475ad2 | 489 | */ |
39af1765 ON |
490 | for_each_process(g) { |
491 | if (g->flags & PF_KTHREAD) | |
492 | continue; | |
493 | for_each_thread(g, c) { | |
494 | if (c->mm == mm) | |
495 | goto assign_new_owner; | |
496 | if (c->mm) | |
497 | break; | |
498 | } | |
f87fb599 | 499 | } |
cf475ad2 | 500 | read_unlock(&tasklist_lock); |
31a78f23 BS |
501 | /* |
502 | * We found no owner yet mm_users > 1: this implies that we are | |
503 | * most likely racing with swapoff (try_to_unuse()) or /proc or | |
e5991371 | 504 | * ptrace or page migration (get_task_mm()). Mark owner as NULL. |
31a78f23 | 505 | */ |
987717e5 | 506 | WRITE_ONCE(mm->owner, NULL); |
cf475ad2 BS |
507 | return; |
508 | ||
509 | assign_new_owner: | |
510 | BUG_ON(c == p); | |
511 | get_task_struct(c); | |
512 | /* | |
513 | * The task_lock protects c->mm from changing. | |
514 | * We always want mm->owner->mm == mm | |
515 | */ | |
516 | task_lock(c); | |
e5991371 HD |
517 | /* |
518 | * Delay read_unlock() till we have the task_lock() | |
519 | * to ensure that c does not slip away underneath us | |
520 | */ | |
521 | read_unlock(&tasklist_lock); | |
cf475ad2 BS |
522 | if (c->mm != mm) { |
523 | task_unlock(c); | |
524 | put_task_struct(c); | |
525 | goto retry; | |
526 | } | |
987717e5 | 527 | WRITE_ONCE(mm->owner, c); |
bd74fdae | 528 | lru_gen_migrate_mm(mm); |
cf475ad2 BS |
529 | task_unlock(c); |
530 | put_task_struct(c); | |
531 | } | |
f98bafa0 | 532 | #endif /* CONFIG_MEMCG */ |
cf475ad2 | 533 | |
1da177e4 LT |
534 | /* |
535 | * Turn us into a lazy TLB process if we | |
536 | * aren't already.. | |
537 | */ | |
0039962a | 538 | static void exit_mm(void) |
1da177e4 | 539 | { |
0039962a | 540 | struct mm_struct *mm = current->mm; |
1da177e4 | 541 | |
4610ba7a | 542 | exit_mm_release(current, mm); |
1da177e4 LT |
543 | if (!mm) |
544 | return; | |
d8ed45c5 | 545 | mmap_read_lock(mm); |
aa464ba9 | 546 | mmgrab_lazy_tlb(mm); |
0039962a | 547 | BUG_ON(mm != current->active_mm); |
1da177e4 | 548 | /* more a memory barrier than a real lock */ |
0039962a | 549 | task_lock(current); |
5bc78502 MD |
550 | /* |
551 | * When a thread stops operating on an address space, the loop | |
552 | * in membarrier_private_expedited() may not observe that | |
553 | * tsk->mm, and the loop in membarrier_global_expedited() may | |
554 | * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED | |
555 | * rq->membarrier_state, so those would not issue an IPI. | |
556 | * Membarrier requires a memory barrier after accessing | |
557 | * user-space memory, before clearing tsk->mm or the | |
558 | * rq->membarrier_state. | |
559 | */ | |
560 | smp_mb__after_spinlock(); | |
561 | local_irq_disable(); | |
0039962a | 562 | current->mm = NULL; |
5bc78502 | 563 | membarrier_update_current_mm(NULL); |
1da177e4 | 564 | enter_lazy_tlb(mm, current); |
5bc78502 | 565 | local_irq_enable(); |
0039962a | 566 | task_unlock(current); |
5bc78502 | 567 | mmap_read_unlock(mm); |
cf475ad2 | 568 | mm_update_next_owner(mm); |
1da177e4 | 569 | mmput(mm); |
c32b3cbe | 570 | if (test_thread_flag(TIF_MEMDIE)) |
38531201 | 571 | exit_oom_victim(); |
1da177e4 LT |
572 | } |
573 | ||
c9dc05bf ON |
574 | static struct task_struct *find_alive_thread(struct task_struct *p) |
575 | { | |
576 | struct task_struct *t; | |
577 | ||
578 | for_each_thread(p, t) { | |
579 | if (!(t->flags & PF_EXITING)) | |
580 | return t; | |
581 | } | |
582 | return NULL; | |
583 | } | |
584 | ||
8fb335e0 AV |
585 | static struct task_struct *find_child_reaper(struct task_struct *father, |
586 | struct list_head *dead) | |
1109909c ON |
587 | __releases(&tasklist_lock) |
588 | __acquires(&tasklist_lock) | |
589 | { | |
590 | struct pid_namespace *pid_ns = task_active_pid_ns(father); | |
591 | struct task_struct *reaper = pid_ns->child_reaper; | |
8fb335e0 | 592 | struct task_struct *p, *n; |
1109909c ON |
593 | |
594 | if (likely(reaper != father)) | |
595 | return reaper; | |
596 | ||
c9dc05bf ON |
597 | reaper = find_alive_thread(father); |
598 | if (reaper) { | |
1109909c ON |
599 | pid_ns->child_reaper = reaper; |
600 | return reaper; | |
601 | } | |
602 | ||
603 | write_unlock_irq(&tasklist_lock); | |
8fb335e0 AV |
604 | |
605 | list_for_each_entry_safe(p, n, dead, ptrace_entry) { | |
606 | list_del_init(&p->ptrace_entry); | |
607 | release_task(p); | |
608 | } | |
609 | ||
1109909c ON |
610 | zap_pid_ns_processes(pid_ns); |
611 | write_lock_irq(&tasklist_lock); | |
612 | ||
613 | return father; | |
614 | } | |
615 | ||
1da177e4 | 616 | /* |
ebec18a6 LP |
617 | * When we die, we re-parent all our children, and try to: |
618 | * 1. give them to another thread in our thread group, if such a member exists | |
619 | * 2. give it to the first ancestor process which prctl'd itself as a | |
620 | * child_subreaper for its children (like a service manager) | |
621 | * 3. give it to the init process (PID 1) in our pid namespace | |
1da177e4 | 622 | */ |
1109909c ON |
623 | static struct task_struct *find_new_reaper(struct task_struct *father, |
624 | struct task_struct *child_reaper) | |
1da177e4 | 625 | { |
c9dc05bf | 626 | struct task_struct *thread, *reaper; |
1da177e4 | 627 | |
c9dc05bf ON |
628 | thread = find_alive_thread(father); |
629 | if (thread) | |
950bbabb | 630 | return thread; |
1da177e4 | 631 | |
7d24e2df | 632 | if (father->signal->has_child_subreaper) { |
c6c70f44 | 633 | unsigned int ns_level = task_pid(father)->level; |
ebec18a6 | 634 | /* |
175aed3f | 635 | * Find the first ->is_child_subreaper ancestor in our pid_ns. |
c6c70f44 ON |
636 | * We can't check reaper != child_reaper to ensure we do not |
637 | * cross the namespaces, the exiting parent could be injected | |
638 | * by setns() + fork(). | |
639 | * We check pid->level, this is slightly more efficient than | |
640 | * task_active_pid_ns(reaper) != task_active_pid_ns(father). | |
ebec18a6 | 641 | */ |
c6c70f44 ON |
642 | for (reaper = father->real_parent; |
643 | task_pid(reaper)->level == ns_level; | |
ebec18a6 | 644 | reaper = reaper->real_parent) { |
175aed3f | 645 | if (reaper == &init_task) |
ebec18a6 LP |
646 | break; |
647 | if (!reaper->signal->is_child_subreaper) | |
648 | continue; | |
c9dc05bf ON |
649 | thread = find_alive_thread(reaper); |
650 | if (thread) | |
651 | return thread; | |
ebec18a6 | 652 | } |
1da177e4 | 653 | } |
762a24be | 654 | |
1109909c | 655 | return child_reaper; |
950bbabb ON |
656 | } |
657 | ||
5dfc80be ON |
658 | /* |
659 | * Any that need to be release_task'd are put on the @dead list. | |
660 | */ | |
9cd80bbb | 661 | static void reparent_leader(struct task_struct *father, struct task_struct *p, |
5dfc80be ON |
662 | struct list_head *dead) |
663 | { | |
2831096e | 664 | if (unlikely(p->exit_state == EXIT_DEAD)) |
5dfc80be ON |
665 | return; |
666 | ||
abd50b39 | 667 | /* We don't want people slaying init. */ |
5dfc80be ON |
668 | p->exit_signal = SIGCHLD; |
669 | ||
670 | /* If it has exited notify the new parent about this child's death. */ | |
d21142ec | 671 | if (!p->ptrace && |
5dfc80be | 672 | p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) { |
86773473 | 673 | if (do_notify_parent(p, p->exit_signal)) { |
5dfc80be | 674 | p->exit_state = EXIT_DEAD; |
dc2fd4b0 | 675 | list_add(&p->ptrace_entry, dead); |
5dfc80be ON |
676 | } |
677 | } | |
678 | ||
679 | kill_orphaned_pgrp(p, father); | |
680 | } | |
681 | ||
482a3767 ON |
682 | /* |
683 | * This does two things: | |
684 | * | |
685 | * A. Make init inherit all the child processes | |
686 | * B. Check to see if any process groups have become orphaned | |
687 | * as a result of our exiting, and if they have any stopped | |
688 | * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) | |
689 | */ | |
690 | static void forget_original_parent(struct task_struct *father, | |
691 | struct list_head *dead) | |
1da177e4 | 692 | { |
482a3767 | 693 | struct task_struct *p, *t, *reaper; |
762a24be | 694 | |
7c8bd232 | 695 | if (unlikely(!list_empty(&father->ptraced))) |
482a3767 | 696 | exit_ptrace(father, dead); |
f470021a | 697 | |
7c8bd232 | 698 | /* Can drop and reacquire tasklist_lock */ |
8fb335e0 | 699 | reaper = find_child_reaper(father, dead); |
ad9e206a | 700 | if (list_empty(&father->children)) |
482a3767 | 701 | return; |
1109909c ON |
702 | |
703 | reaper = find_new_reaper(father, reaper); | |
2831096e | 704 | list_for_each_entry(p, &father->children, sibling) { |
57a05918 | 705 | for_each_thread(p, t) { |
22a34c6f MB |
706 | RCU_INIT_POINTER(t->real_parent, reaper); |
707 | BUG_ON((!t->ptrace) != (rcu_access_pointer(t->parent) == father)); | |
57a05918 | 708 | if (likely(!t->ptrace)) |
9cd80bbb | 709 | t->parent = t->real_parent; |
9cd80bbb ON |
710 | if (t->pdeath_signal) |
711 | group_send_sig_info(t->pdeath_signal, | |
01024980 EB |
712 | SEND_SIG_NOINFO, t, |
713 | PIDTYPE_TGID); | |
57a05918 | 714 | } |
2831096e ON |
715 | /* |
716 | * If this is a threaded reparent there is no need to | |
717 | * notify anyone anything has happened. | |
718 | */ | |
719 | if (!same_thread_group(reaper, father)) | |
482a3767 | 720 | reparent_leader(father, p, dead); |
1da177e4 | 721 | } |
2831096e | 722 | list_splice_tail_init(&father->children, &reaper->children); |
1da177e4 LT |
723 | } |
724 | ||
725 | /* | |
726 | * Send signals to all our closest relatives so that they know | |
727 | * to properly mourn us.. | |
728 | */ | |
821c7de7 | 729 | static void exit_notify(struct task_struct *tsk, int group_dead) |
1da177e4 | 730 | { |
53c8f9f1 | 731 | bool autoreap; |
482a3767 ON |
732 | struct task_struct *p, *n; |
733 | LIST_HEAD(dead); | |
1da177e4 | 734 | |
762a24be | 735 | write_lock_irq(&tasklist_lock); |
482a3767 ON |
736 | forget_original_parent(tsk, &dead); |
737 | ||
821c7de7 ON |
738 | if (group_dead) |
739 | kill_orphaned_pgrp(tsk->group_leader, NULL); | |
1da177e4 | 740 | |
b191d649 | 741 | tsk->exit_state = EXIT_ZOMBIE; |
45cdf5cc ON |
742 | if (unlikely(tsk->ptrace)) { |
743 | int sig = thread_group_leader(tsk) && | |
744 | thread_group_empty(tsk) && | |
745 | !ptrace_reparented(tsk) ? | |
746 | tsk->exit_signal : SIGCHLD; | |
747 | autoreap = do_notify_parent(tsk, sig); | |
748 | } else if (thread_group_leader(tsk)) { | |
749 | autoreap = thread_group_empty(tsk) && | |
750 | do_notify_parent(tsk, tsk->exit_signal); | |
751 | } else { | |
752 | autoreap = true; | |
753 | } | |
1da177e4 | 754 | |
30b692d3 CB |
755 | if (autoreap) { |
756 | tsk->exit_state = EXIT_DEAD; | |
6c66e7db | 757 | list_add(&tsk->ptrace_entry, &dead); |
30b692d3 | 758 | } |
1da177e4 | 759 | |
9c339168 ON |
760 | /* mt-exec, de_thread() is waiting for group leader */ |
761 | if (unlikely(tsk->signal->notify_count < 0)) | |
60700e38 | 762 | wake_up_process(tsk->signal->group_exec_task); |
1da177e4 LT |
763 | write_unlock_irq(&tasklist_lock); |
764 | ||
482a3767 ON |
765 | list_for_each_entry_safe(p, n, &dead, ptrace_entry) { |
766 | list_del_init(&p->ptrace_entry); | |
767 | release_task(p); | |
768 | } | |
1da177e4 LT |
769 | } |
770 | ||
e18eecb8 JD |
771 | #ifdef CONFIG_DEBUG_STACK_USAGE |
772 | static void check_stack_usage(void) | |
773 | { | |
774 | static DEFINE_SPINLOCK(low_water_lock); | |
775 | static int lowest_to_date = THREAD_SIZE; | |
e18eecb8 JD |
776 | unsigned long free; |
777 | ||
7c9f8861 | 778 | free = stack_not_used(current); |
e18eecb8 JD |
779 | |
780 | if (free >= lowest_to_date) | |
781 | return; | |
782 | ||
783 | spin_lock(&low_water_lock); | |
784 | if (free < lowest_to_date) { | |
627393d4 | 785 | pr_info("%s (%d) used greatest stack depth: %lu bytes left\n", |
a0be55de | 786 | current->comm, task_pid_nr(current), free); |
e18eecb8 JD |
787 | lowest_to_date = free; |
788 | } | |
789 | spin_unlock(&low_water_lock); | |
790 | } | |
791 | #else | |
792 | static inline void check_stack_usage(void) {} | |
793 | #endif | |
794 | ||
d80f7d7b EB |
795 | static void synchronize_group_exit(struct task_struct *tsk, long code) |
796 | { | |
797 | struct sighand_struct *sighand = tsk->sighand; | |
798 | struct signal_struct *signal = tsk->signal; | |
799 | ||
800 | spin_lock_irq(&sighand->siglock); | |
801 | signal->quick_threads--; | |
802 | if ((signal->quick_threads == 0) && | |
803 | !(signal->flags & SIGNAL_GROUP_EXIT)) { | |
804 | signal->flags = SIGNAL_GROUP_EXIT; | |
805 | signal->group_exit_code = code; | |
806 | signal->group_stop_count = 0; | |
807 | } | |
808 | spin_unlock_irq(&sighand->siglock); | |
809 | } | |
810 | ||
9af6528e | 811 | void __noreturn do_exit(long code) |
1da177e4 LT |
812 | { |
813 | struct task_struct *tsk = current; | |
814 | int group_dead; | |
815 | ||
001c28e5 NP |
816 | WARN_ON(irqs_disabled()); |
817 | ||
d80f7d7b EB |
818 | synchronize_group_exit(tsk, code); |
819 | ||
b1f866b0 | 820 | WARN_ON(tsk->plug); |
22e2c507 | 821 | |
586b58ca | 822 | kcov_task_exit(tsk); |
50b5e49c | 823 | kmsan_task_exit(tsk); |
586b58ca | 824 | |
92307383 | 825 | coredump_task_exit(tsk); |
a288eecc | 826 | ptrace_event(PTRACE_EVENT_EXIT, code); |
fd593511 | 827 | user_events_exit(tsk); |
1da177e4 | 828 | |
f552a27a | 829 | io_uring_files_cancel(); |
d12619b5 | 830 | exit_signals(tsk); /* sets PF_EXITING */ |
1da177e4 | 831 | |
51229b49 | 832 | acct_update_integrals(tsk); |
1da177e4 | 833 | group_dead = atomic_dec_and_test(&tsk->signal->live); |
c3068951 | 834 | if (group_dead) { |
43cf75d9 | 835 | /* |
836 | * If the last thread of global init has exited, panic | |
837 | * immediately to get a useable coredump. | |
838 | */ | |
839 | if (unlikely(is_global_init(tsk))) | |
840 | panic("Attempted to kill init! exitcode=0x%08x\n", | |
841 | tsk->signal->group_exit_code ?: (int)code); | |
842 | ||
baa73d9e | 843 | #ifdef CONFIG_POSIX_TIMERS |
778e9a9c | 844 | hrtimer_cancel(&tsk->signal->real_timer); |
d5b36a4d | 845 | exit_itimers(tsk); |
baa73d9e | 846 | #endif |
1f10206c JP |
847 | if (tsk->mm) |
848 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm); | |
c3068951 | 849 | } |
f6ec29a4 | 850 | acct_collect(code, group_dead); |
522ed776 MT |
851 | if (group_dead) |
852 | tty_audit_exit(); | |
a4ff8dba | 853 | audit_free(tsk); |
115085ea | 854 | |
48d212a2 | 855 | tsk->exit_code = code; |
115085ea | 856 | taskstats_exit(tsk, group_dead); |
c757249a | 857 | |
0039962a | 858 | exit_mm(); |
1da177e4 | 859 | |
0e464814 | 860 | if (group_dead) |
f6ec29a4 | 861 | acct_process(); |
0a16b607 MD |
862 | trace_sched_process_exit(tsk); |
863 | ||
1da177e4 | 864 | exit_sem(tsk); |
b34a6b1d | 865 | exit_shm(tsk); |
1ec7f1dd AV |
866 | exit_files(tsk); |
867 | exit_fs(tsk); | |
c39df5fa ON |
868 | if (group_dead) |
869 | disassociate_ctty(1); | |
8aac6270 | 870 | exit_task_namespaces(tsk); |
ed3e694d | 871 | exit_task_work(tsk); |
e6464694 | 872 | exit_thread(tsk); |
0b3fcf17 SE |
873 | |
874 | /* | |
875 | * Flush inherited counters to the parent - before the parent | |
876 | * gets woken up by child-exit notifications. | |
877 | * | |
878 | * because of cgroup mode, must be called before cgroup_exit() | |
879 | */ | |
880 | perf_event_exit_task(tsk); | |
881 | ||
8e5bfa8c | 882 | sched_autogroup_exit_task(tsk); |
1ec41830 | 883 | cgroup_exit(tsk); |
1da177e4 | 884 | |
24f1e32c FW |
885 | /* |
886 | * FIXME: do that only when needed, using sched_exit tracepoint | |
887 | */ | |
7c8df286 | 888 | flush_ptrace_hw_breakpoint(tsk); |
33b2fb30 | 889 | |
ccdd29ff | 890 | exit_tasks_rcu_start(); |
821c7de7 | 891 | exit_notify(tsk, group_dead); |
ef982393 | 892 | proc_exit_connector(tsk); |
c11600e4 | 893 | mpol_put_task_policy(tsk); |
42b2dd0a | 894 | #ifdef CONFIG_FUTEX |
c87e2837 IM |
895 | if (unlikely(current->pi_state_cache)) |
896 | kfree(current->pi_state_cache); | |
42b2dd0a | 897 | #endif |
de5097c2 | 898 | /* |
9a11b49a | 899 | * Make sure we are holding no locks: |
de5097c2 | 900 | */ |
1b1d2fb4 | 901 | debug_check_no_locks_held(); |
1da177e4 | 902 | |
afc847b7 | 903 | if (tsk->io_context) |
b69f2292 | 904 | exit_io_context(tsk); |
afc847b7 | 905 | |
b92ce558 | 906 | if (tsk->splice_pipe) |
4b8a8f1e | 907 | free_pipe_info(tsk->splice_pipe); |
b92ce558 | 908 | |
5640f768 ED |
909 | if (tsk->task_frag.page) |
910 | put_page(tsk->task_frag.page); | |
911 | ||
1a03d3f1 | 912 | exit_task_stack_account(tsk); |
e0e81739 | 913 | |
4bcb8232 | 914 | check_stack_usage(); |
7407251a | 915 | preempt_disable(); |
54848d73 WF |
916 | if (tsk->nr_dirtied) |
917 | __this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied); | |
f41d911f | 918 | exit_rcu(); |
ccdd29ff | 919 | exit_tasks_rcu_finish(); |
b5740f4b | 920 | |
b09be676 | 921 | lockdep_free_task(tsk); |
9af6528e | 922 | do_task_dead(); |
1da177e4 | 923 | } |
012914da | 924 | |
0e25498f EB |
925 | void __noreturn make_task_dead(int signr) |
926 | { | |
927 | /* | |
928 | * Take the task off the cpu after something catastrophic has | |
929 | * happened. | |
05ea0424 EB |
930 | * |
931 | * We can get here from a kernel oops, sometimes with preemption off. | |
932 | * Start by checking for critical errors. | |
933 | * Then fix up important state like USER_DS and preemption. | |
934 | * Then do everything else. | |
0e25498f | 935 | */ |
05ea0424 | 936 | struct task_struct *tsk = current; |
7535b832 | 937 | unsigned int limit; |
05ea0424 EB |
938 | |
939 | if (unlikely(in_interrupt())) | |
940 | panic("Aiee, killing interrupt handler!"); | |
941 | if (unlikely(!tsk->pid)) | |
942 | panic("Attempted to kill the idle task!"); | |
943 | ||
001c28e5 NP |
944 | if (unlikely(irqs_disabled())) { |
945 | pr_info("note: %s[%d] exited with irqs disabled\n", | |
946 | current->comm, task_pid_nr(current)); | |
947 | local_irq_enable(); | |
948 | } | |
05ea0424 EB |
949 | if (unlikely(in_atomic())) { |
950 | pr_info("note: %s[%d] exited with preempt_count %d\n", | |
951 | current->comm, task_pid_nr(current), | |
952 | preempt_count()); | |
953 | preempt_count_set(PREEMPT_ENABLED); | |
954 | } | |
955 | ||
d4ccd54d JH |
956 | /* |
957 | * Every time the system oopses, if the oops happens while a reference | |
958 | * to an object was held, the reference leaks. | |
959 | * If the oops doesn't also leak memory, repeated oopsing can cause | |
960 | * reference counters to wrap around (if they're not using refcount_t). | |
961 | * This means that repeated oopsing can make unexploitable-looking bugs | |
962 | * exploitable through repeated oopsing. | |
963 | * To make sure this can't happen, place an upper bound on how often the | |
964 | * kernel may oops without panic(). | |
965 | */ | |
7535b832 KC |
966 | limit = READ_ONCE(oops_limit); |
967 | if (atomic_inc_return(&oops_count) >= limit && limit) | |
968 | panic("Oopsed too often (kernel.oops_limit is %d)", limit); | |
d4ccd54d | 969 | |
05ea0424 EB |
970 | /* |
971 | * We're taking recursive faults here in make_task_dead. Safest is to just | |
972 | * leave this task alone and wait for reboot. | |
973 | */ | |
974 | if (unlikely(tsk->flags & PF_EXITING)) { | |
975 | pr_alert("Fixing recursive fault but reboot is needed!\n"); | |
976 | futex_exit_recursive(tsk); | |
912616f1 EB |
977 | tsk->exit_state = EXIT_DEAD; |
978 | refcount_inc(&tsk->rcu_users); | |
7f80a2fd | 979 | do_task_dead(); |
05ea0424 EB |
980 | } |
981 | ||
0e25498f EB |
982 | do_exit(signr); |
983 | } | |
984 | ||
754fe8d2 | 985 | SYSCALL_DEFINE1(exit, int, error_code) |
1da177e4 LT |
986 | { |
987 | do_exit((error_code&0xff)<<8); | |
988 | } | |
989 | ||
1da177e4 LT |
990 | /* |
991 | * Take down every thread in the group. This is called by fatal signals | |
992 | * as well as by sys_exit_group (below). | |
993 | */ | |
eae654f1 | 994 | void __noreturn |
1da177e4 LT |
995 | do_group_exit(int exit_code) |
996 | { | |
bfc4b089 ON |
997 | struct signal_struct *sig = current->signal; |
998 | ||
49697335 | 999 | if (sig->flags & SIGNAL_GROUP_EXIT) |
bfc4b089 | 1000 | exit_code = sig->group_exit_code; |
49697335 EB |
1001 | else if (sig->group_exec_task) |
1002 | exit_code = 0; | |
cbe9dac3 | 1003 | else { |
1da177e4 | 1004 | struct sighand_struct *const sighand = current->sighand; |
a0be55de | 1005 | |
1da177e4 | 1006 | spin_lock_irq(&sighand->siglock); |
49697335 | 1007 | if (sig->flags & SIGNAL_GROUP_EXIT) |
1da177e4 LT |
1008 | /* Another thread got here before we took the lock. */ |
1009 | exit_code = sig->group_exit_code; | |
49697335 EB |
1010 | else if (sig->group_exec_task) |
1011 | exit_code = 0; | |
1da177e4 | 1012 | else { |
1da177e4 | 1013 | sig->group_exit_code = exit_code; |
ed5d2cac | 1014 | sig->flags = SIGNAL_GROUP_EXIT; |
1da177e4 LT |
1015 | zap_other_threads(current); |
1016 | } | |
1017 | spin_unlock_irq(&sighand->siglock); | |
1da177e4 LT |
1018 | } |
1019 | ||
1020 | do_exit(exit_code); | |
1021 | /* NOTREACHED */ | |
1022 | } | |
1023 | ||
1024 | /* | |
1025 | * this kills every thread in the thread group. Note that any externally | |
1026 | * wait4()-ing process will get the correct exit code - even if this | |
1027 | * thread is not the thread group leader. | |
1028 | */ | |
754fe8d2 | 1029 | SYSCALL_DEFINE1(exit_group, int, error_code) |
1da177e4 LT |
1030 | { |
1031 | do_group_exit((error_code & 0xff) << 8); | |
2ed7c03e HC |
1032 | /* NOTREACHED */ |
1033 | return 0; | |
1da177e4 LT |
1034 | } |
1035 | ||
989264f4 | 1036 | static int eligible_pid(struct wait_opts *wo, struct task_struct *p) |
1da177e4 | 1037 | { |
5c01ba49 ON |
1038 | return wo->wo_type == PIDTYPE_MAX || |
1039 | task_pid_type(p, wo->wo_type) == wo->wo_pid; | |
1040 | } | |
1da177e4 | 1041 | |
bf959931 ON |
1042 | static int |
1043 | eligible_child(struct wait_opts *wo, bool ptrace, struct task_struct *p) | |
5c01ba49 ON |
1044 | { |
1045 | if (!eligible_pid(wo, p)) | |
1046 | return 0; | |
bf959931 ON |
1047 | |
1048 | /* | |
1049 | * Wait for all children (clone and not) if __WALL is set or | |
1050 | * if it is traced by us. | |
1051 | */ | |
1052 | if (ptrace || (wo->wo_flags & __WALL)) | |
1053 | return 1; | |
1054 | ||
1055 | /* | |
1056 | * Otherwise, wait for clone children *only* if __WCLONE is set; | |
1057 | * otherwise, wait for non-clone children *only*. | |
1058 | * | |
1059 | * Note: a "clone" child here is one that reports to its parent | |
1060 | * using a signal other than SIGCHLD, or a non-leader thread which | |
1061 | * we can only see if it is traced by us. | |
1062 | */ | |
1063 | if ((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE)) | |
1da177e4 | 1064 | return 0; |
1da177e4 | 1065 | |
14dd0b81 | 1066 | return 1; |
1da177e4 LT |
1067 | } |
1068 | ||
1da177e4 LT |
1069 | /* |
1070 | * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold | |
1071 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1072 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1073 | * released the lock and the system call should return. | |
1074 | */ | |
9e8ae01d | 1075 | static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) |
1da177e4 | 1076 | { |
67d7ddde | 1077 | int state, status; |
6c5f3e7b | 1078 | pid_t pid = task_pid_vnr(p); |
43e13cc1 | 1079 | uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p)); |
67d7ddde | 1080 | struct waitid_info *infop; |
1da177e4 | 1081 | |
9e8ae01d | 1082 | if (!likely(wo->wo_flags & WEXITED)) |
98abed02 RM |
1083 | return 0; |
1084 | ||
9e8ae01d | 1085 | if (unlikely(wo->wo_flags & WNOWAIT)) { |
907c311f EB |
1086 | status = (p->signal->flags & SIGNAL_GROUP_EXIT) |
1087 | ? p->signal->group_exit_code : p->exit_code; | |
1da177e4 LT |
1088 | get_task_struct(p); |
1089 | read_unlock(&tasklist_lock); | |
1029a2b5 | 1090 | sched_annotate_sleep(); |
e61a2502 AV |
1091 | if (wo->wo_rusage) |
1092 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage); | |
bb380ec3 | 1093 | put_task_struct(p); |
76d9871e | 1094 | goto out_info; |
1da177e4 | 1095 | } |
1da177e4 | 1096 | /* |
abd50b39 | 1097 | * Move the task's state to DEAD/TRACE, only one thread can do this. |
1da177e4 | 1098 | */ |
f6507f83 ON |
1099 | state = (ptrace_reparented(p) && thread_group_leader(p)) ? |
1100 | EXIT_TRACE : EXIT_DEAD; | |
abd50b39 | 1101 | if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE) |
1da177e4 | 1102 | return 0; |
986094df ON |
1103 | /* |
1104 | * We own this thread, nobody else can reap it. | |
1105 | */ | |
1106 | read_unlock(&tasklist_lock); | |
1107 | sched_annotate_sleep(); | |
f6507f83 | 1108 | |
befca967 | 1109 | /* |
f6507f83 | 1110 | * Check thread_group_leader() to exclude the traced sub-threads. |
befca967 | 1111 | */ |
f6507f83 | 1112 | if (state == EXIT_DEAD && thread_group_leader(p)) { |
f953ccd0 ON |
1113 | struct signal_struct *sig = p->signal; |
1114 | struct signal_struct *psig = current->signal; | |
1f10206c | 1115 | unsigned long maxrss; |
5613fda9 | 1116 | u64 tgutime, tgstime; |
3795e161 | 1117 | |
1da177e4 LT |
1118 | /* |
1119 | * The resource counters for the group leader are in its | |
1120 | * own task_struct. Those for dead threads in the group | |
1121 | * are in its signal_struct, as are those for the child | |
1122 | * processes it has previously reaped. All these | |
1123 | * accumulate in the parent's signal_struct c* fields. | |
1124 | * | |
1125 | * We don't bother to take a lock here to protect these | |
f953ccd0 ON |
1126 | * p->signal fields because the whole thread group is dead |
1127 | * and nobody can change them. | |
1128 | * | |
dcca3475 | 1129 | * psig->stats_lock also protects us from our sub-threads |
c1be35a1 | 1130 | * which can reap other children at the same time. |
0cf55e1e | 1131 | * |
a0be55de IA |
1132 | * We use thread_group_cputime_adjusted() to get times for |
1133 | * the thread group, which consolidates times for all threads | |
1134 | * in the group including the group leader. | |
1da177e4 | 1135 | */ |
e80d0a1a | 1136 | thread_group_cputime_adjusted(p, &tgutime, &tgstime); |
c1be35a1 | 1137 | write_seqlock_irq(&psig->stats_lock); |
64861634 MS |
1138 | psig->cutime += tgutime + sig->cutime; |
1139 | psig->cstime += tgstime + sig->cstime; | |
6fac4829 | 1140 | psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime; |
3795e161 JJ |
1141 | psig->cmin_flt += |
1142 | p->min_flt + sig->min_flt + sig->cmin_flt; | |
1143 | psig->cmaj_flt += | |
1144 | p->maj_flt + sig->maj_flt + sig->cmaj_flt; | |
1145 | psig->cnvcsw += | |
1146 | p->nvcsw + sig->nvcsw + sig->cnvcsw; | |
1147 | psig->cnivcsw += | |
1148 | p->nivcsw + sig->nivcsw + sig->cnivcsw; | |
6eaeeaba ED |
1149 | psig->cinblock += |
1150 | task_io_get_inblock(p) + | |
1151 | sig->inblock + sig->cinblock; | |
1152 | psig->coublock += | |
1153 | task_io_get_oublock(p) + | |
1154 | sig->oublock + sig->coublock; | |
1f10206c JP |
1155 | maxrss = max(sig->maxrss, sig->cmaxrss); |
1156 | if (psig->cmaxrss < maxrss) | |
1157 | psig->cmaxrss = maxrss; | |
5995477a AR |
1158 | task_io_accounting_add(&psig->ioac, &p->ioac); |
1159 | task_io_accounting_add(&psig->ioac, &sig->ioac); | |
c1be35a1 | 1160 | write_sequnlock_irq(&psig->stats_lock); |
1da177e4 LT |
1161 | } |
1162 | ||
ce72a16f AV |
1163 | if (wo->wo_rusage) |
1164 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage); | |
1da177e4 LT |
1165 | status = (p->signal->flags & SIGNAL_GROUP_EXIT) |
1166 | ? p->signal->group_exit_code : p->exit_code; | |
359566fa | 1167 | wo->wo_stat = status; |
2f4e6e2a | 1168 | |
b4360690 | 1169 | if (state == EXIT_TRACE) { |
1da177e4 | 1170 | write_lock_irq(&tasklist_lock); |
2f4e6e2a ON |
1171 | /* We dropped tasklist, ptracer could die and untrace */ |
1172 | ptrace_unlink(p); | |
b4360690 ON |
1173 | |
1174 | /* If parent wants a zombie, don't release it now */ | |
1175 | state = EXIT_ZOMBIE; | |
1176 | if (do_notify_parent(p, p->exit_signal)) | |
1177 | state = EXIT_DEAD; | |
abd50b39 | 1178 | p->exit_state = state; |
1da177e4 LT |
1179 | write_unlock_irq(&tasklist_lock); |
1180 | } | |
abd50b39 | 1181 | if (state == EXIT_DEAD) |
1da177e4 | 1182 | release_task(p); |
2f4e6e2a | 1183 | |
76d9871e AV |
1184 | out_info: |
1185 | infop = wo->wo_info; | |
1186 | if (infop) { | |
1187 | if ((status & 0x7f) == 0) { | |
1188 | infop->cause = CLD_EXITED; | |
1189 | infop->status = status >> 8; | |
1190 | } else { | |
1191 | infop->cause = (status & 0x80) ? CLD_DUMPED : CLD_KILLED; | |
1192 | infop->status = status & 0x7f; | |
1193 | } | |
1194 | infop->pid = pid; | |
1195 | infop->uid = uid; | |
1196 | } | |
1197 | ||
67d7ddde | 1198 | return pid; |
1da177e4 LT |
1199 | } |
1200 | ||
90bc8d8b ON |
1201 | static int *task_stopped_code(struct task_struct *p, bool ptrace) |
1202 | { | |
1203 | if (ptrace) { | |
570ac933 | 1204 | if (task_is_traced(p) && !(p->jobctl & JOBCTL_LISTENING)) |
90bc8d8b ON |
1205 | return &p->exit_code; |
1206 | } else { | |
1207 | if (p->signal->flags & SIGNAL_STOP_STOPPED) | |
1208 | return &p->signal->group_exit_code; | |
1209 | } | |
1210 | return NULL; | |
1211 | } | |
1212 | ||
19e27463 TH |
1213 | /** |
1214 | * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED | |
1215 | * @wo: wait options | |
1216 | * @ptrace: is the wait for ptrace | |
1217 | * @p: task to wait for | |
1218 | * | |
1219 | * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED. | |
1220 | * | |
1221 | * CONTEXT: | |
1222 | * read_lock(&tasklist_lock), which is released if return value is | |
1223 | * non-zero. Also, grabs and releases @p->sighand->siglock. | |
1224 | * | |
1225 | * RETURNS: | |
1226 | * 0 if wait condition didn't exist and search for other wait conditions | |
1227 | * should continue. Non-zero return, -errno on failure and @p's pid on | |
1228 | * success, implies that tasklist_lock is released and wait condition | |
1229 | * search should terminate. | |
1da177e4 | 1230 | */ |
9e8ae01d ON |
1231 | static int wait_task_stopped(struct wait_opts *wo, |
1232 | int ptrace, struct task_struct *p) | |
1da177e4 | 1233 | { |
67d7ddde AV |
1234 | struct waitid_info *infop; |
1235 | int exit_code, *p_code, why; | |
ee7c82da | 1236 | uid_t uid = 0; /* unneeded, required by compiler */ |
c8950783 | 1237 | pid_t pid; |
1da177e4 | 1238 | |
47918025 ON |
1239 | /* |
1240 | * Traditionally we see ptrace'd stopped tasks regardless of options. | |
1241 | */ | |
9e8ae01d | 1242 | if (!ptrace && !(wo->wo_flags & WUNTRACED)) |
98abed02 RM |
1243 | return 0; |
1244 | ||
19e27463 TH |
1245 | if (!task_stopped_code(p, ptrace)) |
1246 | return 0; | |
1247 | ||
ee7c82da ON |
1248 | exit_code = 0; |
1249 | spin_lock_irq(&p->sighand->siglock); | |
1250 | ||
90bc8d8b ON |
1251 | p_code = task_stopped_code(p, ptrace); |
1252 | if (unlikely(!p_code)) | |
ee7c82da ON |
1253 | goto unlock_sig; |
1254 | ||
90bc8d8b | 1255 | exit_code = *p_code; |
ee7c82da ON |
1256 | if (!exit_code) |
1257 | goto unlock_sig; | |
1258 | ||
9e8ae01d | 1259 | if (!unlikely(wo->wo_flags & WNOWAIT)) |
90bc8d8b | 1260 | *p_code = 0; |
ee7c82da | 1261 | |
8ca937a6 | 1262 | uid = from_kuid_munged(current_user_ns(), task_uid(p)); |
ee7c82da ON |
1263 | unlock_sig: |
1264 | spin_unlock_irq(&p->sighand->siglock); | |
1265 | if (!exit_code) | |
1da177e4 LT |
1266 | return 0; |
1267 | ||
1268 | /* | |
1269 | * Now we are pretty sure this task is interesting. | |
1270 | * Make sure it doesn't get reaped out from under us while we | |
1271 | * give up the lock and then examine it below. We don't want to | |
1272 | * keep holding onto the tasklist_lock while we call getrusage and | |
1273 | * possibly take page faults for user memory. | |
1274 | */ | |
1275 | get_task_struct(p); | |
6c5f3e7b | 1276 | pid = task_pid_vnr(p); |
f470021a | 1277 | why = ptrace ? CLD_TRAPPED : CLD_STOPPED; |
1da177e4 | 1278 | read_unlock(&tasklist_lock); |
1029a2b5 | 1279 | sched_annotate_sleep(); |
e61a2502 AV |
1280 | if (wo->wo_rusage) |
1281 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage); | |
bb380ec3 | 1282 | put_task_struct(p); |
1da177e4 | 1283 | |
bb380ec3 AV |
1284 | if (likely(!(wo->wo_flags & WNOWAIT))) |
1285 | wo->wo_stat = (exit_code << 8) | 0x7f; | |
1da177e4 | 1286 | |
9e8ae01d | 1287 | infop = wo->wo_info; |
67d7ddde AV |
1288 | if (infop) { |
1289 | infop->cause = why; | |
1290 | infop->status = exit_code; | |
1291 | infop->pid = pid; | |
1292 | infop->uid = uid; | |
1293 | } | |
67d7ddde | 1294 | return pid; |
1da177e4 LT |
1295 | } |
1296 | ||
1297 | /* | |
1298 | * Handle do_wait work for one task in a live, non-stopped state. | |
1299 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold | |
1300 | * the lock and this task is uninteresting. If we return nonzero, we have | |
1301 | * released the lock and the system call should return. | |
1302 | */ | |
9e8ae01d | 1303 | static int wait_task_continued(struct wait_opts *wo, struct task_struct *p) |
1da177e4 | 1304 | { |
bb380ec3 | 1305 | struct waitid_info *infop; |
1da177e4 LT |
1306 | pid_t pid; |
1307 | uid_t uid; | |
1308 | ||
9e8ae01d | 1309 | if (!unlikely(wo->wo_flags & WCONTINUED)) |
98abed02 RM |
1310 | return 0; |
1311 | ||
1da177e4 LT |
1312 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) |
1313 | return 0; | |
1314 | ||
1315 | spin_lock_irq(&p->sighand->siglock); | |
1316 | /* Re-check with the lock held. */ | |
1317 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) { | |
1318 | spin_unlock_irq(&p->sighand->siglock); | |
1319 | return 0; | |
1320 | } | |
9e8ae01d | 1321 | if (!unlikely(wo->wo_flags & WNOWAIT)) |
1da177e4 | 1322 | p->signal->flags &= ~SIGNAL_STOP_CONTINUED; |
8ca937a6 | 1323 | uid = from_kuid_munged(current_user_ns(), task_uid(p)); |
1da177e4 LT |
1324 | spin_unlock_irq(&p->sighand->siglock); |
1325 | ||
6c5f3e7b | 1326 | pid = task_pid_vnr(p); |
1da177e4 LT |
1327 | get_task_struct(p); |
1328 | read_unlock(&tasklist_lock); | |
1029a2b5 | 1329 | sched_annotate_sleep(); |
e61a2502 AV |
1330 | if (wo->wo_rusage) |
1331 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage); | |
bb380ec3 | 1332 | put_task_struct(p); |
1da177e4 | 1333 | |
bb380ec3 AV |
1334 | infop = wo->wo_info; |
1335 | if (!infop) { | |
359566fa | 1336 | wo->wo_stat = 0xffff; |
1da177e4 | 1337 | } else { |
bb380ec3 AV |
1338 | infop->cause = CLD_CONTINUED; |
1339 | infop->pid = pid; | |
1340 | infop->uid = uid; | |
1341 | infop->status = SIGCONT; | |
1da177e4 | 1342 | } |
bb380ec3 | 1343 | return pid; |
1da177e4 LT |
1344 | } |
1345 | ||
98abed02 RM |
1346 | /* |
1347 | * Consider @p for a wait by @parent. | |
1348 | * | |
9e8ae01d | 1349 | * -ECHILD should be in ->notask_error before the first call. |
98abed02 RM |
1350 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. |
1351 | * Returns zero if the search for a child should continue; | |
9e8ae01d | 1352 | * then ->notask_error is 0 if @p is an eligible child, |
3a2f5a59 | 1353 | * or still -ECHILD. |
98abed02 | 1354 | */ |
b6e763f0 ON |
1355 | static int wait_consider_task(struct wait_opts *wo, int ptrace, |
1356 | struct task_struct *p) | |
98abed02 | 1357 | { |
3245d6ac ON |
1358 | /* |
1359 | * We can race with wait_task_zombie() from another thread. | |
1360 | * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition | |
1361 | * can't confuse the checks below. | |
1362 | */ | |
6aa7de05 | 1363 | int exit_state = READ_ONCE(p->exit_state); |
b3ab0316 ON |
1364 | int ret; |
1365 | ||
3245d6ac | 1366 | if (unlikely(exit_state == EXIT_DEAD)) |
b3ab0316 ON |
1367 | return 0; |
1368 | ||
bf959931 | 1369 | ret = eligible_child(wo, ptrace, p); |
14dd0b81 | 1370 | if (!ret) |
98abed02 RM |
1371 | return ret; |
1372 | ||
3245d6ac | 1373 | if (unlikely(exit_state == EXIT_TRACE)) { |
50b8d257 | 1374 | /* |
abd50b39 ON |
1375 | * ptrace == 0 means we are the natural parent. In this case |
1376 | * we should clear notask_error, debugger will notify us. | |
50b8d257 | 1377 | */ |
abd50b39 | 1378 | if (likely(!ptrace)) |
50b8d257 | 1379 | wo->notask_error = 0; |
823b018e | 1380 | return 0; |
50b8d257 | 1381 | } |
823b018e | 1382 | |
377d75da ON |
1383 | if (likely(!ptrace) && unlikely(p->ptrace)) { |
1384 | /* | |
1385 | * If it is traced by its real parent's group, just pretend | |
1386 | * the caller is ptrace_do_wait() and reap this child if it | |
1387 | * is zombie. | |
1388 | * | |
1389 | * This also hides group stop state from real parent; otherwise | |
1390 | * a single stop can be reported twice as group and ptrace stop. | |
1391 | * If a ptracer wants to distinguish these two events for its | |
1392 | * own children it should create a separate process which takes | |
1393 | * the role of real parent. | |
1394 | */ | |
1395 | if (!ptrace_reparented(p)) | |
1396 | ptrace = 1; | |
1397 | } | |
1398 | ||
45cb24a1 | 1399 | /* slay zombie? */ |
3245d6ac | 1400 | if (exit_state == EXIT_ZOMBIE) { |
9b84cca2 | 1401 | /* we don't reap group leaders with subthreads */ |
7c733eb3 ON |
1402 | if (!delay_group_leader(p)) { |
1403 | /* | |
1404 | * A zombie ptracee is only visible to its ptracer. | |
1405 | * Notification and reaping will be cascaded to the | |
1406 | * real parent when the ptracer detaches. | |
1407 | */ | |
1408 | if (unlikely(ptrace) || likely(!p->ptrace)) | |
1409 | return wait_task_zombie(wo, p); | |
1410 | } | |
98abed02 | 1411 | |
f470021a | 1412 | /* |
9b84cca2 TH |
1413 | * Allow access to stopped/continued state via zombie by |
1414 | * falling through. Clearing of notask_error is complex. | |
1415 | * | |
1416 | * When !@ptrace: | |
1417 | * | |
1418 | * If WEXITED is set, notask_error should naturally be | |
1419 | * cleared. If not, subset of WSTOPPED|WCONTINUED is set, | |
1420 | * so, if there are live subthreads, there are events to | |
1421 | * wait for. If all subthreads are dead, it's still safe | |
1422 | * to clear - this function will be called again in finite | |
1423 | * amount time once all the subthreads are released and | |
1424 | * will then return without clearing. | |
1425 | * | |
1426 | * When @ptrace: | |
1427 | * | |
1428 | * Stopped state is per-task and thus can't change once the | |
1429 | * target task dies. Only continued and exited can happen. | |
1430 | * Clear notask_error if WCONTINUED | WEXITED. | |
1431 | */ | |
1432 | if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED))) | |
1433 | wo->notask_error = 0; | |
1434 | } else { | |
1435 | /* | |
1436 | * @p is alive and it's gonna stop, continue or exit, so | |
1437 | * there always is something to wait for. | |
f470021a | 1438 | */ |
9e8ae01d | 1439 | wo->notask_error = 0; |
f470021a RM |
1440 | } |
1441 | ||
98abed02 | 1442 | /* |
45cb24a1 TH |
1443 | * Wait for stopped. Depending on @ptrace, different stopped state |
1444 | * is used and the two don't interact with each other. | |
98abed02 | 1445 | */ |
19e27463 TH |
1446 | ret = wait_task_stopped(wo, ptrace, p); |
1447 | if (ret) | |
1448 | return ret; | |
98abed02 RM |
1449 | |
1450 | /* | |
45cb24a1 TH |
1451 | * Wait for continued. There's only one continued state and the |
1452 | * ptracer can consume it which can confuse the real parent. Don't | |
1453 | * use WCONTINUED from ptracer. You don't need or want it. | |
98abed02 | 1454 | */ |
9e8ae01d | 1455 | return wait_task_continued(wo, p); |
98abed02 RM |
1456 | } |
1457 | ||
1458 | /* | |
1459 | * Do the work of do_wait() for one thread in the group, @tsk. | |
1460 | * | |
9e8ae01d | 1461 | * -ECHILD should be in ->notask_error before the first call. |
98abed02 RM |
1462 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. |
1463 | * Returns zero if the search for a child should continue; then | |
9e8ae01d | 1464 | * ->notask_error is 0 if there were any eligible children, |
3a2f5a59 | 1465 | * or still -ECHILD. |
98abed02 | 1466 | */ |
9e8ae01d | 1467 | static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk) |
98abed02 RM |
1468 | { |
1469 | struct task_struct *p; | |
1470 | ||
1471 | list_for_each_entry(p, &tsk->children, sibling) { | |
9cd80bbb | 1472 | int ret = wait_consider_task(wo, 0, p); |
a0be55de | 1473 | |
9cd80bbb ON |
1474 | if (ret) |
1475 | return ret; | |
98abed02 RM |
1476 | } |
1477 | ||
1478 | return 0; | |
1479 | } | |
1480 | ||
9e8ae01d | 1481 | static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk) |
98abed02 RM |
1482 | { |
1483 | struct task_struct *p; | |
1484 | ||
f470021a | 1485 | list_for_each_entry(p, &tsk->ptraced, ptrace_entry) { |
b6e763f0 | 1486 | int ret = wait_consider_task(wo, 1, p); |
a0be55de | 1487 | |
f470021a | 1488 | if (ret) |
98abed02 | 1489 | return ret; |
98abed02 RM |
1490 | } |
1491 | ||
1492 | return 0; | |
1493 | } | |
1494 | ||
2e521a20 | 1495 | bool pid_child_should_wake(struct wait_opts *wo, struct task_struct *p) |
9d900d4e JA |
1496 | { |
1497 | if (!eligible_pid(wo, p)) | |
1498 | return false; | |
1499 | ||
1500 | if ((wo->wo_flags & __WNOTHREAD) && wo->child_wait.private != p->parent) | |
1501 | return false; | |
1502 | ||
1503 | return true; | |
1504 | } | |
1505 | ||
ac6424b9 | 1506 | static int child_wait_callback(wait_queue_entry_t *wait, unsigned mode, |
0b7570e7 ON |
1507 | int sync, void *key) |
1508 | { | |
1509 | struct wait_opts *wo = container_of(wait, struct wait_opts, | |
1510 | child_wait); | |
1511 | struct task_struct *p = key; | |
1512 | ||
9d900d4e JA |
1513 | if (pid_child_should_wake(wo, p)) |
1514 | return default_wake_function(wait, mode, sync, key); | |
0b7570e7 | 1515 | |
9d900d4e | 1516 | return 0; |
0b7570e7 ON |
1517 | } |
1518 | ||
a7f0765e ON |
1519 | void __wake_up_parent(struct task_struct *p, struct task_struct *parent) |
1520 | { | |
0b7570e7 | 1521 | __wake_up_sync_key(&parent->signal->wait_chldexit, |
ce4dd442 | 1522 | TASK_INTERRUPTIBLE, p); |
a7f0765e ON |
1523 | } |
1524 | ||
5449162a JN |
1525 | static bool is_effectively_child(struct wait_opts *wo, bool ptrace, |
1526 | struct task_struct *target) | |
1527 | { | |
1528 | struct task_struct *parent = | |
1529 | !ptrace ? target->real_parent : target->parent; | |
1530 | ||
1531 | return current == parent || (!(wo->wo_flags & __WNOTHREAD) && | |
1532 | same_thread_group(current, parent)); | |
1533 | } | |
1534 | ||
1535 | /* | |
1536 | * Optimization for waiting on PIDTYPE_PID. No need to iterate through child | |
1537 | * and tracee lists to find the target task. | |
1538 | */ | |
1539 | static int do_wait_pid(struct wait_opts *wo) | |
1540 | { | |
1541 | bool ptrace; | |
1542 | struct task_struct *target; | |
1543 | int retval; | |
1544 | ||
1545 | ptrace = false; | |
1546 | target = pid_task(wo->wo_pid, PIDTYPE_TGID); | |
1547 | if (target && is_effectively_child(wo, ptrace, target)) { | |
1548 | retval = wait_consider_task(wo, ptrace, target); | |
1549 | if (retval) | |
1550 | return retval; | |
1551 | } | |
1552 | ||
1553 | ptrace = true; | |
1554 | target = pid_task(wo->wo_pid, PIDTYPE_PID); | |
1555 | if (target && target->ptrace && | |
1556 | is_effectively_child(wo, ptrace, target)) { | |
1557 | retval = wait_consider_task(wo, ptrace, target); | |
1558 | if (retval) | |
1559 | return retval; | |
1560 | } | |
1561 | ||
1562 | return 0; | |
1563 | } | |
1564 | ||
2e521a20 | 1565 | long __do_wait(struct wait_opts *wo) |
1da177e4 | 1566 | { |
06a101ca | 1567 | long retval; |
0a16b607 | 1568 | |
98abed02 | 1569 | /* |
3da56d16 | 1570 | * If there is nothing that can match our criteria, just get out. |
9e8ae01d ON |
1571 | * We will clear ->notask_error to zero if we see any child that |
1572 | * might later match our criteria, even if we are not able to reap | |
1573 | * it yet. | |
98abed02 | 1574 | */ |
64a16caf | 1575 | wo->notask_error = -ECHILD; |
9e8ae01d | 1576 | if ((wo->wo_type < PIDTYPE_MAX) && |
1722c14a | 1577 | (!wo->wo_pid || !pid_has_task(wo->wo_pid, wo->wo_type))) |
64a16caf | 1578 | goto notask; |
161550d7 | 1579 | |
1da177e4 | 1580 | read_lock(&tasklist_lock); |
9e8ae01d | 1581 | |
5449162a JN |
1582 | if (wo->wo_type == PIDTYPE_PID) { |
1583 | retval = do_wait_pid(wo); | |
64a16caf | 1584 | if (retval) |
06a101ca | 1585 | return retval; |
5449162a JN |
1586 | } else { |
1587 | struct task_struct *tsk = current; | |
1588 | ||
1589 | do { | |
1590 | retval = do_wait_thread(wo, tsk); | |
1591 | if (retval) | |
06a101ca | 1592 | return retval; |
98abed02 | 1593 | |
5449162a JN |
1594 | retval = ptrace_do_wait(wo, tsk); |
1595 | if (retval) | |
06a101ca | 1596 | return retval; |
5449162a JN |
1597 | |
1598 | if (wo->wo_flags & __WNOTHREAD) | |
1599 | break; | |
1600 | } while_each_thread(current, tsk); | |
1601 | } | |
1da177e4 | 1602 | read_unlock(&tasklist_lock); |
f2cc3eb1 | 1603 | |
64a16caf | 1604 | notask: |
9e8ae01d | 1605 | retval = wo->notask_error; |
06a101ca JA |
1606 | if (!retval && !(wo->wo_flags & WNOHANG)) |
1607 | return -ERESTARTSYS; | |
1608 | ||
1609 | return retval; | |
1610 | } | |
1611 | ||
1612 | static long do_wait(struct wait_opts *wo) | |
1613 | { | |
1614 | int retval; | |
1615 | ||
1616 | trace_sched_process_wait(wo->wo_pid); | |
1617 | ||
1618 | init_waitqueue_func_entry(&wo->child_wait, child_wait_callback); | |
1619 | wo->child_wait.private = current; | |
1620 | add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait); | |
1621 | ||
1622 | do { | |
1623 | set_current_state(TASK_INTERRUPTIBLE); | |
1624 | retval = __do_wait(wo); | |
1625 | if (retval != -ERESTARTSYS) | |
1626 | break; | |
1627 | if (signal_pending(current)) | |
1628 | break; | |
1629 | schedule(); | |
1630 | } while (1); | |
1631 | ||
f95d39d1 | 1632 | __set_current_state(TASK_RUNNING); |
0b7570e7 | 1633 | remove_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait); |
1da177e4 LT |
1634 | return retval; |
1635 | } | |
1636 | ||
2e521a20 JA |
1637 | int kernel_waitid_prepare(struct wait_opts *wo, int which, pid_t upid, |
1638 | struct waitid_info *infop, int options, | |
1639 | struct rusage *ru) | |
1da177e4 | 1640 | { |
eda7e9d4 | 1641 | unsigned int f_flags = 0; |
161550d7 EB |
1642 | struct pid *pid = NULL; |
1643 | enum pid_type type; | |
1da177e4 | 1644 | |
91c4e8ea ON |
1645 | if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED| |
1646 | __WNOTHREAD|__WCLONE|__WALL)) | |
1da177e4 LT |
1647 | return -EINVAL; |
1648 | if (!(options & (WEXITED|WSTOPPED|WCONTINUED))) | |
1649 | return -EINVAL; | |
1650 | ||
1651 | switch (which) { | |
1652 | case P_ALL: | |
161550d7 | 1653 | type = PIDTYPE_MAX; |
1da177e4 LT |
1654 | break; |
1655 | case P_PID: | |
161550d7 EB |
1656 | type = PIDTYPE_PID; |
1657 | if (upid <= 0) | |
1da177e4 | 1658 | return -EINVAL; |
3695eae5 CB |
1659 | |
1660 | pid = find_get_pid(upid); | |
1da177e4 LT |
1661 | break; |
1662 | case P_PGID: | |
161550d7 | 1663 | type = PIDTYPE_PGID; |
821cc7b0 | 1664 | if (upid < 0) |
1da177e4 | 1665 | return -EINVAL; |
3695eae5 | 1666 | |
821cc7b0 EB |
1667 | if (upid) |
1668 | pid = find_get_pid(upid); | |
1669 | else | |
1670 | pid = get_task_pid(current, PIDTYPE_PGID); | |
3695eae5 CB |
1671 | break; |
1672 | case P_PIDFD: | |
1673 | type = PIDTYPE_PID; | |
1674 | if (upid < 0) | |
1da177e4 | 1675 | return -EINVAL; |
3695eae5 | 1676 | |
ba7d25f3 | 1677 | pid = pidfd_get_pid(upid, &f_flags); |
3695eae5 CB |
1678 | if (IS_ERR(pid)) |
1679 | return PTR_ERR(pid); | |
ba7d25f3 | 1680 | |
1da177e4 LT |
1681 | break; |
1682 | default: | |
1683 | return -EINVAL; | |
1684 | } | |
1685 | ||
eda7e9d4 JA |
1686 | wo->wo_type = type; |
1687 | wo->wo_pid = pid; | |
1688 | wo->wo_flags = options; | |
1689 | wo->wo_info = infop; | |
1690 | wo->wo_rusage = ru; | |
ba7d25f3 | 1691 | if (f_flags & O_NONBLOCK) |
eda7e9d4 JA |
1692 | wo->wo_flags |= WNOHANG; |
1693 | ||
1694 | return 0; | |
1695 | } | |
1696 | ||
1697 | static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop, | |
1698 | int options, struct rusage *ru) | |
1699 | { | |
1700 | struct wait_opts wo; | |
1701 | long ret; | |
1702 | ||
1703 | ret = kernel_waitid_prepare(&wo, which, upid, infop, options, ru); | |
1704 | if (ret) | |
1705 | return ret; | |
ba7d25f3 | 1706 | |
9e8ae01d | 1707 | ret = do_wait(&wo); |
eda7e9d4 | 1708 | if (!ret && !(options & WNOHANG) && (wo.wo_flags & WNOHANG)) |
ba7d25f3 | 1709 | ret = -EAGAIN; |
dfe16dfa | 1710 | |
eda7e9d4 | 1711 | put_pid(wo.wo_pid); |
1da177e4 LT |
1712 | return ret; |
1713 | } | |
1714 | ||
ce72a16f AV |
1715 | SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, |
1716 | infop, int, options, struct rusage __user *, ru) | |
1717 | { | |
1718 | struct rusage r; | |
67d7ddde AV |
1719 | struct waitid_info info = {.status = 0}; |
1720 | long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL); | |
634a8160 | 1721 | int signo = 0; |
6c85501f | 1722 | |
634a8160 AV |
1723 | if (err > 0) { |
1724 | signo = SIGCHLD; | |
1725 | err = 0; | |
ce72a16f AV |
1726 | if (ru && copy_to_user(ru, &r, sizeof(struct rusage))) |
1727 | return -EFAULT; | |
1728 | } | |
67d7ddde AV |
1729 | if (!infop) |
1730 | return err; | |
1731 | ||
41cd7805 | 1732 | if (!user_write_access_begin(infop, sizeof(*infop))) |
1c9fec47 | 1733 | return -EFAULT; |
96ca579a | 1734 | |
634a8160 | 1735 | unsafe_put_user(signo, &infop->si_signo, Efault); |
4c48abe9 | 1736 | unsafe_put_user(0, &infop->si_errno, Efault); |
cc731525 | 1737 | unsafe_put_user(info.cause, &infop->si_code, Efault); |
4c48abe9 AV |
1738 | unsafe_put_user(info.pid, &infop->si_pid, Efault); |
1739 | unsafe_put_user(info.uid, &infop->si_uid, Efault); | |
1740 | unsafe_put_user(info.status, &infop->si_status, Efault); | |
41cd7805 | 1741 | user_write_access_end(); |
ce72a16f | 1742 | return err; |
4c48abe9 | 1743 | Efault: |
41cd7805 | 1744 | user_write_access_end(); |
4c48abe9 | 1745 | return -EFAULT; |
ce72a16f AV |
1746 | } |
1747 | ||
92ebce5a AV |
1748 | long kernel_wait4(pid_t upid, int __user *stat_addr, int options, |
1749 | struct rusage *ru) | |
1da177e4 | 1750 | { |
9e8ae01d | 1751 | struct wait_opts wo; |
161550d7 EB |
1752 | struct pid *pid = NULL; |
1753 | enum pid_type type; | |
1da177e4 LT |
1754 | long ret; |
1755 | ||
1756 | if (options & ~(WNOHANG|WUNTRACED|WCONTINUED| | |
1757 | __WNOTHREAD|__WCLONE|__WALL)) | |
1758 | return -EINVAL; | |
161550d7 | 1759 | |
dd83c161 | 1760 | /* -INT_MIN is not defined */ |
1761 | if (upid == INT_MIN) | |
1762 | return -ESRCH; | |
1763 | ||
161550d7 EB |
1764 | if (upid == -1) |
1765 | type = PIDTYPE_MAX; | |
1766 | else if (upid < 0) { | |
1767 | type = PIDTYPE_PGID; | |
1768 | pid = find_get_pid(-upid); | |
1769 | } else if (upid == 0) { | |
1770 | type = PIDTYPE_PGID; | |
2ae448ef | 1771 | pid = get_task_pid(current, PIDTYPE_PGID); |
161550d7 EB |
1772 | } else /* upid > 0 */ { |
1773 | type = PIDTYPE_PID; | |
1774 | pid = find_get_pid(upid); | |
1775 | } | |
1776 | ||
9e8ae01d ON |
1777 | wo.wo_type = type; |
1778 | wo.wo_pid = pid; | |
1779 | wo.wo_flags = options | WEXITED; | |
1780 | wo.wo_info = NULL; | |
359566fa | 1781 | wo.wo_stat = 0; |
9e8ae01d ON |
1782 | wo.wo_rusage = ru; |
1783 | ret = do_wait(&wo); | |
161550d7 | 1784 | put_pid(pid); |
359566fa AV |
1785 | if (ret > 0 && stat_addr && put_user(wo.wo_stat, stat_addr)) |
1786 | ret = -EFAULT; | |
1da177e4 | 1787 | |
1da177e4 LT |
1788 | return ret; |
1789 | } | |
1790 | ||
8043fc14 CH |
1791 | int kernel_wait(pid_t pid, int *stat) |
1792 | { | |
1793 | struct wait_opts wo = { | |
1794 | .wo_type = PIDTYPE_PID, | |
1795 | .wo_pid = find_get_pid(pid), | |
1796 | .wo_flags = WEXITED, | |
1797 | }; | |
1798 | int ret; | |
1799 | ||
1800 | ret = do_wait(&wo); | |
1801 | if (ret > 0 && wo.wo_stat) | |
1802 | *stat = wo.wo_stat; | |
1803 | put_pid(wo.wo_pid); | |
1804 | return ret; | |
1805 | } | |
1806 | ||
ce72a16f AV |
1807 | SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr, |
1808 | int, options, struct rusage __user *, ru) | |
1809 | { | |
1810 | struct rusage r; | |
1811 | long err = kernel_wait4(upid, stat_addr, options, ru ? &r : NULL); | |
1812 | ||
1813 | if (err > 0) { | |
1814 | if (ru && copy_to_user(ru, &r, sizeof(struct rusage))) | |
1815 | return -EFAULT; | |
1816 | } | |
1817 | return err; | |
1818 | } | |
1819 | ||
1da177e4 LT |
1820 | #ifdef __ARCH_WANT_SYS_WAITPID |
1821 | ||
1822 | /* | |
1823 | * sys_waitpid() remains for compatibility. waitpid() should be | |
1824 | * implemented by calling sys_wait4() from libc.a. | |
1825 | */ | |
17da2bd9 | 1826 | SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options) |
1da177e4 | 1827 | { |
d300b610 | 1828 | return kernel_wait4(pid, stat_addr, options, NULL); |
1da177e4 LT |
1829 | } |
1830 | ||
1831 | #endif | |
7e95a225 AV |
1832 | |
1833 | #ifdef CONFIG_COMPAT | |
1834 | COMPAT_SYSCALL_DEFINE4(wait4, | |
1835 | compat_pid_t, pid, | |
1836 | compat_uint_t __user *, stat_addr, | |
1837 | int, options, | |
1838 | struct compat_rusage __user *, ru) | |
1839 | { | |
ce72a16f AV |
1840 | struct rusage r; |
1841 | long err = kernel_wait4(pid, stat_addr, options, ru ? &r : NULL); | |
1842 | if (err > 0) { | |
1843 | if (ru && put_compat_rusage(&r, ru)) | |
1844 | return -EFAULT; | |
7e95a225 | 1845 | } |
ce72a16f | 1846 | return err; |
7e95a225 AV |
1847 | } |
1848 | ||
1849 | COMPAT_SYSCALL_DEFINE5(waitid, | |
1850 | int, which, compat_pid_t, pid, | |
1851 | struct compat_siginfo __user *, infop, int, options, | |
1852 | struct compat_rusage __user *, uru) | |
1853 | { | |
7e95a225 | 1854 | struct rusage ru; |
67d7ddde AV |
1855 | struct waitid_info info = {.status = 0}; |
1856 | long err = kernel_waitid(which, pid, &info, options, uru ? &ru : NULL); | |
634a8160 AV |
1857 | int signo = 0; |
1858 | if (err > 0) { | |
1859 | signo = SIGCHLD; | |
1860 | err = 0; | |
6c85501f AV |
1861 | if (uru) { |
1862 | /* kernel_waitid() overwrites everything in ru */ | |
1863 | if (COMPAT_USE_64BIT_TIME) | |
1864 | err = copy_to_user(uru, &ru, sizeof(ru)); | |
1865 | else | |
1866 | err = put_compat_rusage(&ru, uru); | |
1867 | if (err) | |
1868 | return -EFAULT; | |
1869 | } | |
7e95a225 AV |
1870 | } |
1871 | ||
4c48abe9 AV |
1872 | if (!infop) |
1873 | return err; | |
1874 | ||
41cd7805 | 1875 | if (!user_write_access_begin(infop, sizeof(*infop))) |
1c9fec47 | 1876 | return -EFAULT; |
96ca579a | 1877 | |
634a8160 | 1878 | unsafe_put_user(signo, &infop->si_signo, Efault); |
4c48abe9 | 1879 | unsafe_put_user(0, &infop->si_errno, Efault); |
cc731525 | 1880 | unsafe_put_user(info.cause, &infop->si_code, Efault); |
4c48abe9 AV |
1881 | unsafe_put_user(info.pid, &infop->si_pid, Efault); |
1882 | unsafe_put_user(info.uid, &infop->si_uid, Efault); | |
1883 | unsafe_put_user(info.status, &infop->si_status, Efault); | |
41cd7805 | 1884 | user_write_access_end(); |
67d7ddde | 1885 | return err; |
4c48abe9 | 1886 | Efault: |
41cd7805 | 1887 | user_write_access_end(); |
4c48abe9 | 1888 | return -EFAULT; |
7e95a225 AV |
1889 | } |
1890 | #endif | |
7c2c11b2 | 1891 | |
38fd525a EB |
1892 | /** |
1893 | * thread_group_exited - check that a thread group has exited | |
1894 | * @pid: tgid of thread group to be checked. | |
1895 | * | |
1896 | * Test if the thread group represented by tgid has exited (all | |
1897 | * threads are zombies, dead or completely gone). | |
1898 | * | |
1899 | * Return: true if the thread group has exited. false otherwise. | |
1900 | */ | |
1901 | bool thread_group_exited(struct pid *pid) | |
1902 | { | |
1903 | struct task_struct *task; | |
1904 | bool exited; | |
1905 | ||
1906 | rcu_read_lock(); | |
1907 | task = pid_task(pid, PIDTYPE_PID); | |
1908 | exited = !task || | |
1909 | (READ_ONCE(task->exit_state) && thread_group_empty(task)); | |
1910 | rcu_read_unlock(); | |
1911 | ||
1912 | return exited; | |
1913 | } | |
1914 | EXPORT_SYMBOL(thread_group_exited); | |
1915 | ||
c27cd083 MR |
1916 | /* |
1917 | * This needs to be __function_aligned as GCC implicitly makes any | |
1918 | * implementation of abort() cold and drops alignment specified by | |
1919 | * -falign-functions=N. | |
1920 | * | |
1921 | * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c11 | |
1922 | */ | |
1923 | __weak __function_aligned void abort(void) | |
7c2c11b2 SM |
1924 | { |
1925 | BUG(); | |
1926 | ||
1927 | /* if that doesn't kill us, halt */ | |
1928 | panic("Oops failed to kill thread"); | |
1929 | } | |
dc8635b7 | 1930 | EXPORT_SYMBOL(abort); |