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