1 // SPDX-License-Identifier: GPL-2.0-only
5 * Copyright (C) 1991, 1992 Linus Torvalds
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>
72 #include <linux/uaccess.h>
73 #include <asm/unistd.h>
74 #include <asm/mmu_context.h>
77 * The default value should be high enough to not crash a system that randomly
78 * crashes its kernel from time to time, but low enough to at least not permit
79 * overflowing 32-bit refcounts or the ldsem writer count.
81 static unsigned int oops_limit
= 10000;
84 static struct ctl_table kern_exit_table
[] = {
86 .procname
= "oops_limit",
88 .maxlen
= sizeof(oops_limit
),
90 .proc_handler
= proc_douintvec
,
95 static __init
int kernel_exit_sysctls_init(void)
97 register_sysctl_init("kernel", kern_exit_table
);
100 late_initcall(kernel_exit_sysctls_init
);
103 static atomic_t oops_count
= ATOMIC_INIT(0);
106 static ssize_t
oops_count_show(struct kobject
*kobj
, struct kobj_attribute
*attr
,
109 return sysfs_emit(page
, "%d\n", atomic_read(&oops_count
));
112 static struct kobj_attribute oops_count_attr
= __ATTR_RO(oops_count
);
114 static __init
int kernel_exit_sysfs_init(void)
116 sysfs_add_file_to_group(kernel_kobj
, &oops_count_attr
.attr
, NULL
);
119 late_initcall(kernel_exit_sysfs_init
);
122 static void __unhash_process(struct task_struct
*p
, bool group_dead
)
125 detach_pid(p
, PIDTYPE_PID
);
127 detach_pid(p
, PIDTYPE_TGID
);
128 detach_pid(p
, PIDTYPE_PGID
);
129 detach_pid(p
, PIDTYPE_SID
);
131 list_del_rcu(&p
->tasks
);
132 list_del_init(&p
->sibling
);
133 __this_cpu_dec(process_counts
);
135 list_del_rcu(&p
->thread_group
);
136 list_del_rcu(&p
->thread_node
);
140 * This function expects the tasklist_lock write-locked.
142 static void __exit_signal(struct task_struct
*tsk
)
144 struct signal_struct
*sig
= tsk
->signal
;
145 bool group_dead
= thread_group_leader(tsk
);
146 struct sighand_struct
*sighand
;
147 struct tty_struct
*tty
;
150 sighand
= rcu_dereference_check(tsk
->sighand
,
151 lockdep_tasklist_lock_is_held());
152 spin_lock(&sighand
->siglock
);
154 #ifdef CONFIG_POSIX_TIMERS
155 posix_cpu_timers_exit(tsk
);
157 posix_cpu_timers_exit_group(tsk
);
165 * If there is any task waiting for the group exit
168 if (sig
->notify_count
> 0 && !--sig
->notify_count
)
169 wake_up_process(sig
->group_exec_task
);
171 if (tsk
== sig
->curr_target
)
172 sig
->curr_target
= next_thread(tsk
);
175 add_device_randomness((const void*) &tsk
->se
.sum_exec_runtime
,
176 sizeof(unsigned long long));
179 * Accumulate here the counters for all threads as they die. We could
180 * skip the group leader because it is the last user of signal_struct,
181 * but we want to avoid the race with thread_group_cputime() which can
182 * see the empty ->thread_head list.
184 task_cputime(tsk
, &utime
, &stime
);
185 write_seqlock(&sig
->stats_lock
);
188 sig
->gtime
+= task_gtime(tsk
);
189 sig
->min_flt
+= tsk
->min_flt
;
190 sig
->maj_flt
+= tsk
->maj_flt
;
191 sig
->nvcsw
+= tsk
->nvcsw
;
192 sig
->nivcsw
+= tsk
->nivcsw
;
193 sig
->inblock
+= task_io_get_inblock(tsk
);
194 sig
->oublock
+= task_io_get_oublock(tsk
);
195 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
196 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
198 __unhash_process(tsk
, group_dead
);
199 write_sequnlock(&sig
->stats_lock
);
202 * Do this under ->siglock, we can race with another thread
203 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
205 flush_sigqueue(&tsk
->pending
);
207 spin_unlock(&sighand
->siglock
);
209 __cleanup_sighand(sighand
);
210 clear_tsk_thread_flag(tsk
, TIF_SIGPENDING
);
212 flush_sigqueue(&sig
->shared_pending
);
217 static void delayed_put_task_struct(struct rcu_head
*rhp
)
219 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
221 kprobe_flush_task(tsk
);
222 rethook_flush_task(tsk
);
223 perf_event_delayed_put(tsk
);
224 trace_sched_process_free(tsk
);
225 put_task_struct(tsk
);
228 void put_task_struct_rcu_user(struct task_struct
*task
)
230 if (refcount_dec_and_test(&task
->rcu_users
))
231 call_rcu(&task
->rcu
, delayed_put_task_struct
);
234 void __weak
release_thread(struct task_struct
*dead_task
)
238 void release_task(struct task_struct
*p
)
240 struct task_struct
*leader
;
241 struct pid
*thread_pid
;
244 /* don't need to get the RCU readlock here - the process is dead and
245 * can't be modifying its own credentials. But shut RCU-lockdep up */
247 dec_rlimit_ucounts(task_ucounts(p
), UCOUNT_RLIMIT_NPROC
, 1);
252 write_lock_irq(&tasklist_lock
);
253 ptrace_release_task(p
);
254 thread_pid
= get_pid(p
->thread_pid
);
258 * If we are the last non-leader member of the thread
259 * group, and the leader is zombie, then notify the
260 * group leader's parent process. (if it wants notification.)
263 leader
= p
->group_leader
;
264 if (leader
!= p
&& thread_group_empty(leader
)
265 && leader
->exit_state
== EXIT_ZOMBIE
) {
267 * If we were the last child thread and the leader has
268 * exited already, and the leader's parent ignores SIGCHLD,
269 * then we are the one who should release the leader.
271 zap_leader
= do_notify_parent(leader
, leader
->exit_signal
);
273 leader
->exit_state
= EXIT_DEAD
;
276 write_unlock_irq(&tasklist_lock
);
277 seccomp_filter_release(p
);
278 proc_flush_pid(thread_pid
);
281 put_task_struct_rcu_user(p
);
284 if (unlikely(zap_leader
))
288 int rcuwait_wake_up(struct rcuwait
*w
)
291 struct task_struct
*task
;
296 * Order condition vs @task, such that everything prior to the load
297 * of @task is visible. This is the condition as to why the user called
298 * rcuwait_wake() in the first place. Pairs with set_current_state()
299 * barrier (A) in rcuwait_wait_event().
302 * [S] tsk = current [S] cond = true
308 task
= rcu_dereference(w
->task
);
310 ret
= wake_up_process(task
);
315 EXPORT_SYMBOL_GPL(rcuwait_wake_up
);
318 * Determine if a process group is "orphaned", according to the POSIX
319 * definition in 2.2.2.52. Orphaned process groups are not to be affected
320 * by terminal-generated stop signals. Newly orphaned process groups are
321 * to receive a SIGHUP and a SIGCONT.
323 * "I ask you, have you ever known what it is to be an orphan?"
325 static int will_become_orphaned_pgrp(struct pid
*pgrp
,
326 struct task_struct
*ignored_task
)
328 struct task_struct
*p
;
330 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
331 if ((p
== ignored_task
) ||
332 (p
->exit_state
&& thread_group_empty(p
)) ||
333 is_global_init(p
->real_parent
))
336 if (task_pgrp(p
->real_parent
) != pgrp
&&
337 task_session(p
->real_parent
) == task_session(p
))
339 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
344 int is_current_pgrp_orphaned(void)
348 read_lock(&tasklist_lock
);
349 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
350 read_unlock(&tasklist_lock
);
355 static bool has_stopped_jobs(struct pid
*pgrp
)
357 struct task_struct
*p
;
359 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
360 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
362 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
368 * Check to see if any process groups have become orphaned as
369 * a result of our exiting, and if they have any stopped jobs,
370 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
373 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
375 struct pid
*pgrp
= task_pgrp(tsk
);
376 struct task_struct
*ignored_task
= tsk
;
379 /* exit: our father is in a different pgrp than
380 * we are and we were the only connection outside.
382 parent
= tsk
->real_parent
;
384 /* reparent: our child is in a different pgrp than
385 * we are, and it was the only connection outside.
389 if (task_pgrp(parent
) != pgrp
&&
390 task_session(parent
) == task_session(tsk
) &&
391 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
392 has_stopped_jobs(pgrp
)) {
393 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
394 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
398 static void coredump_task_exit(struct task_struct
*tsk
)
400 struct core_state
*core_state
;
403 * Serialize with any possible pending coredump.
404 * We must hold siglock around checking core_state
405 * and setting PF_POSTCOREDUMP. The core-inducing thread
406 * will increment ->nr_threads for each thread in the
407 * group without PF_POSTCOREDUMP set.
409 spin_lock_irq(&tsk
->sighand
->siglock
);
410 tsk
->flags
|= PF_POSTCOREDUMP
;
411 core_state
= tsk
->signal
->core_state
;
412 spin_unlock_irq(&tsk
->sighand
->siglock
);
414 struct core_thread self
;
417 if (self
.task
->flags
& PF_SIGNALED
)
418 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
422 * Implies mb(), the result of xchg() must be visible
423 * to core_state->dumper.
425 if (atomic_dec_and_test(&core_state
->nr_threads
))
426 complete(&core_state
->startup
);
429 set_current_state(TASK_UNINTERRUPTIBLE
|TASK_FREEZABLE
);
430 if (!self
.task
) /* see coredump_finish() */
434 __set_current_state(TASK_RUNNING
);
440 * A task is exiting. If it owned this mm, find a new owner for the mm.
442 void mm_update_next_owner(struct mm_struct
*mm
)
444 struct task_struct
*c
, *g
, *p
= current
;
448 * If the exiting or execing task is not the owner, it's
449 * someone else's problem.
454 * The current owner is exiting/execing and there are no other
455 * candidates. Do not leave the mm pointing to a possibly
456 * freed task structure.
458 if (atomic_read(&mm
->mm_users
) <= 1) {
459 WRITE_ONCE(mm
->owner
, NULL
);
463 read_lock(&tasklist_lock
);
465 * Search in the children
467 list_for_each_entry(c
, &p
->children
, sibling
) {
469 goto assign_new_owner
;
473 * Search in the siblings
475 list_for_each_entry(c
, &p
->real_parent
->children
, sibling
) {
477 goto assign_new_owner
;
481 * Search through everything else, we should not get here often.
483 for_each_process(g
) {
484 if (g
->flags
& PF_KTHREAD
)
486 for_each_thread(g
, c
) {
488 goto assign_new_owner
;
493 read_unlock(&tasklist_lock
);
495 * We found no owner yet mm_users > 1: this implies that we are
496 * most likely racing with swapoff (try_to_unuse()) or /proc or
497 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
499 WRITE_ONCE(mm
->owner
, NULL
);
506 * The task_lock protects c->mm from changing.
507 * We always want mm->owner->mm == mm
511 * Delay read_unlock() till we have the task_lock()
512 * to ensure that c does not slip away underneath us
514 read_unlock(&tasklist_lock
);
520 WRITE_ONCE(mm
->owner
, c
);
521 lru_gen_migrate_mm(mm
);
525 #endif /* CONFIG_MEMCG */
528 * Turn us into a lazy TLB process if we
531 static void exit_mm(void)
533 struct mm_struct
*mm
= current
->mm
;
535 exit_mm_release(current
, mm
);
541 BUG_ON(mm
!= current
->active_mm
);
542 /* more a memory barrier than a real lock */
545 * When a thread stops operating on an address space, the loop
546 * in membarrier_private_expedited() may not observe that
547 * tsk->mm, and the loop in membarrier_global_expedited() may
548 * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED
549 * rq->membarrier_state, so those would not issue an IPI.
550 * Membarrier requires a memory barrier after accessing
551 * user-space memory, before clearing tsk->mm or the
552 * rq->membarrier_state.
554 smp_mb__after_spinlock();
557 membarrier_update_current_mm(NULL
);
558 enter_lazy_tlb(mm
, current
);
560 task_unlock(current
);
561 mmap_read_unlock(mm
);
562 mm_update_next_owner(mm
);
564 if (test_thread_flag(TIF_MEMDIE
))
568 static struct task_struct
*find_alive_thread(struct task_struct
*p
)
570 struct task_struct
*t
;
572 for_each_thread(p
, t
) {
573 if (!(t
->flags
& PF_EXITING
))
579 static struct task_struct
*find_child_reaper(struct task_struct
*father
,
580 struct list_head
*dead
)
581 __releases(&tasklist_lock
)
582 __acquires(&tasklist_lock
)
584 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
585 struct task_struct
*reaper
= pid_ns
->child_reaper
;
586 struct task_struct
*p
, *n
;
588 if (likely(reaper
!= father
))
591 reaper
= find_alive_thread(father
);
593 pid_ns
->child_reaper
= reaper
;
597 write_unlock_irq(&tasklist_lock
);
599 list_for_each_entry_safe(p
, n
, dead
, ptrace_entry
) {
600 list_del_init(&p
->ptrace_entry
);
604 zap_pid_ns_processes(pid_ns
);
605 write_lock_irq(&tasklist_lock
);
611 * When we die, we re-parent all our children, and try to:
612 * 1. give them to another thread in our thread group, if such a member exists
613 * 2. give it to the first ancestor process which prctl'd itself as a
614 * child_subreaper for its children (like a service manager)
615 * 3. give it to the init process (PID 1) in our pid namespace
617 static struct task_struct
*find_new_reaper(struct task_struct
*father
,
618 struct task_struct
*child_reaper
)
620 struct task_struct
*thread
, *reaper
;
622 thread
= find_alive_thread(father
);
626 if (father
->signal
->has_child_subreaper
) {
627 unsigned int ns_level
= task_pid(father
)->level
;
629 * Find the first ->is_child_subreaper ancestor in our pid_ns.
630 * We can't check reaper != child_reaper to ensure we do not
631 * cross the namespaces, the exiting parent could be injected
632 * by setns() + fork().
633 * We check pid->level, this is slightly more efficient than
634 * task_active_pid_ns(reaper) != task_active_pid_ns(father).
636 for (reaper
= father
->real_parent
;
637 task_pid(reaper
)->level
== ns_level
;
638 reaper
= reaper
->real_parent
) {
639 if (reaper
== &init_task
)
641 if (!reaper
->signal
->is_child_subreaper
)
643 thread
= find_alive_thread(reaper
);
653 * Any that need to be release_task'd are put on the @dead list.
655 static void reparent_leader(struct task_struct
*father
, struct task_struct
*p
,
656 struct list_head
*dead
)
658 if (unlikely(p
->exit_state
== EXIT_DEAD
))
661 /* We don't want people slaying init. */
662 p
->exit_signal
= SIGCHLD
;
664 /* If it has exited notify the new parent about this child's death. */
666 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
667 if (do_notify_parent(p
, p
->exit_signal
)) {
668 p
->exit_state
= EXIT_DEAD
;
669 list_add(&p
->ptrace_entry
, dead
);
673 kill_orphaned_pgrp(p
, father
);
677 * This does two things:
679 * A. Make init inherit all the child processes
680 * B. Check to see if any process groups have become orphaned
681 * as a result of our exiting, and if they have any stopped
682 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
684 static void forget_original_parent(struct task_struct
*father
,
685 struct list_head
*dead
)
687 struct task_struct
*p
, *t
, *reaper
;
689 if (unlikely(!list_empty(&father
->ptraced
)))
690 exit_ptrace(father
, dead
);
692 /* Can drop and reacquire tasklist_lock */
693 reaper
= find_child_reaper(father
, dead
);
694 if (list_empty(&father
->children
))
697 reaper
= find_new_reaper(father
, reaper
);
698 list_for_each_entry(p
, &father
->children
, sibling
) {
699 for_each_thread(p
, t
) {
700 RCU_INIT_POINTER(t
->real_parent
, reaper
);
701 BUG_ON((!t
->ptrace
) != (rcu_access_pointer(t
->parent
) == father
));
702 if (likely(!t
->ptrace
))
703 t
->parent
= t
->real_parent
;
704 if (t
->pdeath_signal
)
705 group_send_sig_info(t
->pdeath_signal
,
710 * If this is a threaded reparent there is no need to
711 * notify anyone anything has happened.
713 if (!same_thread_group(reaper
, father
))
714 reparent_leader(father
, p
, dead
);
716 list_splice_tail_init(&father
->children
, &reaper
->children
);
720 * Send signals to all our closest relatives so that they know
721 * to properly mourn us..
723 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
726 struct task_struct
*p
, *n
;
729 write_lock_irq(&tasklist_lock
);
730 forget_original_parent(tsk
, &dead
);
733 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
735 tsk
->exit_state
= EXIT_ZOMBIE
;
736 if (unlikely(tsk
->ptrace
)) {
737 int sig
= thread_group_leader(tsk
) &&
738 thread_group_empty(tsk
) &&
739 !ptrace_reparented(tsk
) ?
740 tsk
->exit_signal
: SIGCHLD
;
741 autoreap
= do_notify_parent(tsk
, sig
);
742 } else if (thread_group_leader(tsk
)) {
743 autoreap
= thread_group_empty(tsk
) &&
744 do_notify_parent(tsk
, tsk
->exit_signal
);
750 tsk
->exit_state
= EXIT_DEAD
;
751 list_add(&tsk
->ptrace_entry
, &dead
);
754 /* mt-exec, de_thread() is waiting for group leader */
755 if (unlikely(tsk
->signal
->notify_count
< 0))
756 wake_up_process(tsk
->signal
->group_exec_task
);
757 write_unlock_irq(&tasklist_lock
);
759 list_for_each_entry_safe(p
, n
, &dead
, ptrace_entry
) {
760 list_del_init(&p
->ptrace_entry
);
765 #ifdef CONFIG_DEBUG_STACK_USAGE
766 static void check_stack_usage(void)
768 static DEFINE_SPINLOCK(low_water_lock
);
769 static int lowest_to_date
= THREAD_SIZE
;
772 free
= stack_not_used(current
);
774 if (free
>= lowest_to_date
)
777 spin_lock(&low_water_lock
);
778 if (free
< lowest_to_date
) {
779 pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
780 current
->comm
, task_pid_nr(current
), free
);
781 lowest_to_date
= free
;
783 spin_unlock(&low_water_lock
);
786 static inline void check_stack_usage(void) {}
789 static void synchronize_group_exit(struct task_struct
*tsk
, long code
)
791 struct sighand_struct
*sighand
= tsk
->sighand
;
792 struct signal_struct
*signal
= tsk
->signal
;
794 spin_lock_irq(&sighand
->siglock
);
795 signal
->quick_threads
--;
796 if ((signal
->quick_threads
== 0) &&
797 !(signal
->flags
& SIGNAL_GROUP_EXIT
)) {
798 signal
->flags
= SIGNAL_GROUP_EXIT
;
799 signal
->group_exit_code
= code
;
800 signal
->group_stop_count
= 0;
802 spin_unlock_irq(&sighand
->siglock
);
805 void __noreturn
do_exit(long code
)
807 struct task_struct
*tsk
= current
;
810 synchronize_group_exit(tsk
, code
);
815 kmsan_task_exit(tsk
);
817 coredump_task_exit(tsk
);
818 ptrace_event(PTRACE_EVENT_EXIT
, code
);
820 validate_creds_for_do_exit(tsk
);
822 io_uring_files_cancel();
823 exit_signals(tsk
); /* sets PF_EXITING */
825 /* sync mm's RSS info before statistics gathering */
827 sync_mm_rss(tsk
->mm
);
828 acct_update_integrals(tsk
);
829 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
832 * If the last thread of global init has exited, panic
833 * immediately to get a useable coredump.
835 if (unlikely(is_global_init(tsk
)))
836 panic("Attempted to kill init! exitcode=0x%08x\n",
837 tsk
->signal
->group_exit_code
?: (int)code
);
839 #ifdef CONFIG_POSIX_TIMERS
840 hrtimer_cancel(&tsk
->signal
->real_timer
);
844 setmax_mm_hiwater_rss(&tsk
->signal
->maxrss
, tsk
->mm
);
846 acct_collect(code
, group_dead
);
851 tsk
->exit_code
= code
;
852 taskstats_exit(tsk
, group_dead
);
858 trace_sched_process_exit(tsk
);
865 disassociate_ctty(1);
866 exit_task_namespaces(tsk
);
871 * Flush inherited counters to the parent - before the parent
872 * gets woken up by child-exit notifications.
874 * because of cgroup mode, must be called before cgroup_exit()
876 perf_event_exit_task(tsk
);
878 sched_autogroup_exit_task(tsk
);
882 * FIXME: do that only when needed, using sched_exit tracepoint
884 flush_ptrace_hw_breakpoint(tsk
);
886 exit_tasks_rcu_start();
887 exit_notify(tsk
, group_dead
);
888 proc_exit_connector(tsk
);
889 mpol_put_task_policy(tsk
);
891 if (unlikely(current
->pi_state_cache
))
892 kfree(current
->pi_state_cache
);
895 * Make sure we are holding no locks:
897 debug_check_no_locks_held();
900 exit_io_context(tsk
);
902 if (tsk
->splice_pipe
)
903 free_pipe_info(tsk
->splice_pipe
);
905 if (tsk
->task_frag
.page
)
906 put_page(tsk
->task_frag
.page
);
908 validate_creds_for_do_exit(tsk
);
909 exit_task_stack_account(tsk
);
914 __this_cpu_add(dirty_throttle_leaks
, tsk
->nr_dirtied
);
916 exit_tasks_rcu_finish();
918 lockdep_free_task(tsk
);
922 void __noreturn
make_task_dead(int signr
)
925 * Take the task off the cpu after something catastrophic has
928 * We can get here from a kernel oops, sometimes with preemption off.
929 * Start by checking for critical errors.
930 * Then fix up important state like USER_DS and preemption.
931 * Then do everything else.
933 struct task_struct
*tsk
= current
;
936 if (unlikely(in_interrupt()))
937 panic("Aiee, killing interrupt handler!");
938 if (unlikely(!tsk
->pid
))
939 panic("Attempted to kill the idle task!");
941 if (unlikely(in_atomic())) {
942 pr_info("note: %s[%d] exited with preempt_count %d\n",
943 current
->comm
, task_pid_nr(current
),
945 preempt_count_set(PREEMPT_ENABLED
);
949 * Every time the system oopses, if the oops happens while a reference
950 * to an object was held, the reference leaks.
951 * If the oops doesn't also leak memory, repeated oopsing can cause
952 * reference counters to wrap around (if they're not using refcount_t).
953 * This means that repeated oopsing can make unexploitable-looking bugs
954 * exploitable through repeated oopsing.
955 * To make sure this can't happen, place an upper bound on how often the
956 * kernel may oops without panic().
958 limit
= READ_ONCE(oops_limit
);
959 if (atomic_inc_return(&oops_count
) >= limit
&& limit
)
960 panic("Oopsed too often (kernel.oops_limit is %d)", limit
);
963 * We're taking recursive faults here in make_task_dead. Safest is to just
964 * leave this task alone and wait for reboot.
966 if (unlikely(tsk
->flags
& PF_EXITING
)) {
967 pr_alert("Fixing recursive fault but reboot is needed!\n");
968 futex_exit_recursive(tsk
);
969 tsk
->exit_state
= EXIT_DEAD
;
970 refcount_inc(&tsk
->rcu_users
);
977 SYSCALL_DEFINE1(exit
, int, error_code
)
979 do_exit((error_code
&0xff)<<8);
983 * Take down every thread in the group. This is called by fatal signals
984 * as well as by sys_exit_group (below).
987 do_group_exit(int exit_code
)
989 struct signal_struct
*sig
= current
->signal
;
991 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
992 exit_code
= sig
->group_exit_code
;
993 else if (sig
->group_exec_task
)
996 struct sighand_struct
*const sighand
= current
->sighand
;
998 spin_lock_irq(&sighand
->siglock
);
999 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
1000 /* Another thread got here before we took the lock. */
1001 exit_code
= sig
->group_exit_code
;
1002 else if (sig
->group_exec_task
)
1005 sig
->group_exit_code
= exit_code
;
1006 sig
->flags
= SIGNAL_GROUP_EXIT
;
1007 zap_other_threads(current
);
1009 spin_unlock_irq(&sighand
->siglock
);
1017 * this kills every thread in the thread group. Note that any externally
1018 * wait4()-ing process will get the correct exit code - even if this
1019 * thread is not the thread group leader.
1021 SYSCALL_DEFINE1(exit_group
, int, error_code
)
1023 do_group_exit((error_code
& 0xff) << 8);
1028 struct waitid_info
{
1036 enum pid_type wo_type
;
1040 struct waitid_info
*wo_info
;
1042 struct rusage
*wo_rusage
;
1044 wait_queue_entry_t child_wait
;
1048 static int eligible_pid(struct wait_opts
*wo
, struct task_struct
*p
)
1050 return wo
->wo_type
== PIDTYPE_MAX
||
1051 task_pid_type(p
, wo
->wo_type
) == wo
->wo_pid
;
1055 eligible_child(struct wait_opts
*wo
, bool ptrace
, struct task_struct
*p
)
1057 if (!eligible_pid(wo
, p
))
1061 * Wait for all children (clone and not) if __WALL is set or
1062 * if it is traced by us.
1064 if (ptrace
|| (wo
->wo_flags
& __WALL
))
1068 * Otherwise, wait for clone children *only* if __WCLONE is set;
1069 * otherwise, wait for non-clone children *only*.
1071 * Note: a "clone" child here is one that reports to its parent
1072 * using a signal other than SIGCHLD, or a non-leader thread which
1073 * we can only see if it is traced by us.
1075 if ((p
->exit_signal
!= SIGCHLD
) ^ !!(wo
->wo_flags
& __WCLONE
))
1082 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1083 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1084 * the lock and this task is uninteresting. If we return nonzero, we have
1085 * released the lock and the system call should return.
1087 static int wait_task_zombie(struct wait_opts
*wo
, struct task_struct
*p
)
1090 pid_t pid
= task_pid_vnr(p
);
1091 uid_t uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1092 struct waitid_info
*infop
;
1094 if (!likely(wo
->wo_flags
& WEXITED
))
1097 if (unlikely(wo
->wo_flags
& WNOWAIT
)) {
1098 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1099 ? p
->signal
->group_exit_code
: p
->exit_code
;
1101 read_unlock(&tasklist_lock
);
1102 sched_annotate_sleep();
1104 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1109 * Move the task's state to DEAD/TRACE, only one thread can do this.
1111 state
= (ptrace_reparented(p
) && thread_group_leader(p
)) ?
1112 EXIT_TRACE
: EXIT_DEAD
;
1113 if (cmpxchg(&p
->exit_state
, EXIT_ZOMBIE
, state
) != EXIT_ZOMBIE
)
1116 * We own this thread, nobody else can reap it.
1118 read_unlock(&tasklist_lock
);
1119 sched_annotate_sleep();
1122 * Check thread_group_leader() to exclude the traced sub-threads.
1124 if (state
== EXIT_DEAD
&& thread_group_leader(p
)) {
1125 struct signal_struct
*sig
= p
->signal
;
1126 struct signal_struct
*psig
= current
->signal
;
1127 unsigned long maxrss
;
1128 u64 tgutime
, tgstime
;
1131 * The resource counters for the group leader are in its
1132 * own task_struct. Those for dead threads in the group
1133 * are in its signal_struct, as are those for the child
1134 * processes it has previously reaped. All these
1135 * accumulate in the parent's signal_struct c* fields.
1137 * We don't bother to take a lock here to protect these
1138 * p->signal fields because the whole thread group is dead
1139 * and nobody can change them.
1141 * psig->stats_lock also protects us from our sub-threads
1142 * which can reap other children at the same time. Until
1143 * we change k_getrusage()-like users to rely on this lock
1144 * we have to take ->siglock as well.
1146 * We use thread_group_cputime_adjusted() to get times for
1147 * the thread group, which consolidates times for all threads
1148 * in the group including the group leader.
1150 thread_group_cputime_adjusted(p
, &tgutime
, &tgstime
);
1151 spin_lock_irq(¤t
->sighand
->siglock
);
1152 write_seqlock(&psig
->stats_lock
);
1153 psig
->cutime
+= tgutime
+ sig
->cutime
;
1154 psig
->cstime
+= tgstime
+ sig
->cstime
;
1155 psig
->cgtime
+= task_gtime(p
) + sig
->gtime
+ sig
->cgtime
;
1157 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1159 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1161 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1163 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1165 task_io_get_inblock(p
) +
1166 sig
->inblock
+ sig
->cinblock
;
1168 task_io_get_oublock(p
) +
1169 sig
->oublock
+ sig
->coublock
;
1170 maxrss
= max(sig
->maxrss
, sig
->cmaxrss
);
1171 if (psig
->cmaxrss
< maxrss
)
1172 psig
->cmaxrss
= maxrss
;
1173 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1174 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1175 write_sequnlock(&psig
->stats_lock
);
1176 spin_unlock_irq(¤t
->sighand
->siglock
);
1180 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1181 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1182 ? p
->signal
->group_exit_code
: p
->exit_code
;
1183 wo
->wo_stat
= status
;
1185 if (state
== EXIT_TRACE
) {
1186 write_lock_irq(&tasklist_lock
);
1187 /* We dropped tasklist, ptracer could die and untrace */
1190 /* If parent wants a zombie, don't release it now */
1191 state
= EXIT_ZOMBIE
;
1192 if (do_notify_parent(p
, p
->exit_signal
))
1194 p
->exit_state
= state
;
1195 write_unlock_irq(&tasklist_lock
);
1197 if (state
== EXIT_DEAD
)
1201 infop
= wo
->wo_info
;
1203 if ((status
& 0x7f) == 0) {
1204 infop
->cause
= CLD_EXITED
;
1205 infop
->status
= status
>> 8;
1207 infop
->cause
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1208 infop
->status
= status
& 0x7f;
1217 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1220 if (task_is_traced(p
) && !(p
->jobctl
& JOBCTL_LISTENING
))
1221 return &p
->exit_code
;
1223 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1224 return &p
->signal
->group_exit_code
;
1230 * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
1232 * @ptrace: is the wait for ptrace
1233 * @p: task to wait for
1235 * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
1238 * read_lock(&tasklist_lock), which is released if return value is
1239 * non-zero. Also, grabs and releases @p->sighand->siglock.
1242 * 0 if wait condition didn't exist and search for other wait conditions
1243 * should continue. Non-zero return, -errno on failure and @p's pid on
1244 * success, implies that tasklist_lock is released and wait condition
1245 * search should terminate.
1247 static int wait_task_stopped(struct wait_opts
*wo
,
1248 int ptrace
, struct task_struct
*p
)
1250 struct waitid_info
*infop
;
1251 int exit_code
, *p_code
, why
;
1252 uid_t uid
= 0; /* unneeded, required by compiler */
1256 * Traditionally we see ptrace'd stopped tasks regardless of options.
1258 if (!ptrace
&& !(wo
->wo_flags
& WUNTRACED
))
1261 if (!task_stopped_code(p
, ptrace
))
1265 spin_lock_irq(&p
->sighand
->siglock
);
1267 p_code
= task_stopped_code(p
, ptrace
);
1268 if (unlikely(!p_code
))
1271 exit_code
= *p_code
;
1275 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1278 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1280 spin_unlock_irq(&p
->sighand
->siglock
);
1285 * Now we are pretty sure this task is interesting.
1286 * Make sure it doesn't get reaped out from under us while we
1287 * give up the lock and then examine it below. We don't want to
1288 * keep holding onto the tasklist_lock while we call getrusage and
1289 * possibly take page faults for user memory.
1292 pid
= task_pid_vnr(p
);
1293 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1294 read_unlock(&tasklist_lock
);
1295 sched_annotate_sleep();
1297 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1300 if (likely(!(wo
->wo_flags
& WNOWAIT
)))
1301 wo
->wo_stat
= (exit_code
<< 8) | 0x7f;
1303 infop
= wo
->wo_info
;
1306 infop
->status
= exit_code
;
1314 * Handle do_wait work for one task in a live, non-stopped state.
1315 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1316 * the lock and this task is uninteresting. If we return nonzero, we have
1317 * released the lock and the system call should return.
1319 static int wait_task_continued(struct wait_opts
*wo
, struct task_struct
*p
)
1321 struct waitid_info
*infop
;
1325 if (!unlikely(wo
->wo_flags
& WCONTINUED
))
1328 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1331 spin_lock_irq(&p
->sighand
->siglock
);
1332 /* Re-check with the lock held. */
1333 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1334 spin_unlock_irq(&p
->sighand
->siglock
);
1337 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1338 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1339 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1340 spin_unlock_irq(&p
->sighand
->siglock
);
1342 pid
= task_pid_vnr(p
);
1344 read_unlock(&tasklist_lock
);
1345 sched_annotate_sleep();
1347 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1350 infop
= wo
->wo_info
;
1352 wo
->wo_stat
= 0xffff;
1354 infop
->cause
= CLD_CONTINUED
;
1357 infop
->status
= SIGCONT
;
1363 * Consider @p for a wait by @parent.
1365 * -ECHILD should be in ->notask_error before the first call.
1366 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1367 * Returns zero if the search for a child should continue;
1368 * then ->notask_error is 0 if @p is an eligible child,
1371 static int wait_consider_task(struct wait_opts
*wo
, int ptrace
,
1372 struct task_struct
*p
)
1375 * We can race with wait_task_zombie() from another thread.
1376 * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
1377 * can't confuse the checks below.
1379 int exit_state
= READ_ONCE(p
->exit_state
);
1382 if (unlikely(exit_state
== EXIT_DEAD
))
1385 ret
= eligible_child(wo
, ptrace
, p
);
1389 if (unlikely(exit_state
== EXIT_TRACE
)) {
1391 * ptrace == 0 means we are the natural parent. In this case
1392 * we should clear notask_error, debugger will notify us.
1394 if (likely(!ptrace
))
1395 wo
->notask_error
= 0;
1399 if (likely(!ptrace
) && unlikely(p
->ptrace
)) {
1401 * If it is traced by its real parent's group, just pretend
1402 * the caller is ptrace_do_wait() and reap this child if it
1405 * This also hides group stop state from real parent; otherwise
1406 * a single stop can be reported twice as group and ptrace stop.
1407 * If a ptracer wants to distinguish these two events for its
1408 * own children it should create a separate process which takes
1409 * the role of real parent.
1411 if (!ptrace_reparented(p
))
1416 if (exit_state
== EXIT_ZOMBIE
) {
1417 /* we don't reap group leaders with subthreads */
1418 if (!delay_group_leader(p
)) {
1420 * A zombie ptracee is only visible to its ptracer.
1421 * Notification and reaping will be cascaded to the
1422 * real parent when the ptracer detaches.
1424 if (unlikely(ptrace
) || likely(!p
->ptrace
))
1425 return wait_task_zombie(wo
, p
);
1429 * Allow access to stopped/continued state via zombie by
1430 * falling through. Clearing of notask_error is complex.
1434 * If WEXITED is set, notask_error should naturally be
1435 * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
1436 * so, if there are live subthreads, there are events to
1437 * wait for. If all subthreads are dead, it's still safe
1438 * to clear - this function will be called again in finite
1439 * amount time once all the subthreads are released and
1440 * will then return without clearing.
1444 * Stopped state is per-task and thus can't change once the
1445 * target task dies. Only continued and exited can happen.
1446 * Clear notask_error if WCONTINUED | WEXITED.
1448 if (likely(!ptrace
) || (wo
->wo_flags
& (WCONTINUED
| WEXITED
)))
1449 wo
->notask_error
= 0;
1452 * @p is alive and it's gonna stop, continue or exit, so
1453 * there always is something to wait for.
1455 wo
->notask_error
= 0;
1459 * Wait for stopped. Depending on @ptrace, different stopped state
1460 * is used and the two don't interact with each other.
1462 ret
= wait_task_stopped(wo
, ptrace
, p
);
1467 * Wait for continued. There's only one continued state and the
1468 * ptracer can consume it which can confuse the real parent. Don't
1469 * use WCONTINUED from ptracer. You don't need or want it.
1471 return wait_task_continued(wo
, p
);
1475 * Do the work of do_wait() for one thread in the group, @tsk.
1477 * -ECHILD should be in ->notask_error before the first call.
1478 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1479 * Returns zero if the search for a child should continue; then
1480 * ->notask_error is 0 if there were any eligible children,
1483 static int do_wait_thread(struct wait_opts
*wo
, struct task_struct
*tsk
)
1485 struct task_struct
*p
;
1487 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1488 int ret
= wait_consider_task(wo
, 0, p
);
1497 static int ptrace_do_wait(struct wait_opts
*wo
, struct task_struct
*tsk
)
1499 struct task_struct
*p
;
1501 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1502 int ret
= wait_consider_task(wo
, 1, p
);
1511 static int child_wait_callback(wait_queue_entry_t
*wait
, unsigned mode
,
1512 int sync
, void *key
)
1514 struct wait_opts
*wo
= container_of(wait
, struct wait_opts
,
1516 struct task_struct
*p
= key
;
1518 if (!eligible_pid(wo
, p
))
1521 if ((wo
->wo_flags
& __WNOTHREAD
) && wait
->private != p
->parent
)
1524 return default_wake_function(wait
, mode
, sync
, key
);
1527 void __wake_up_parent(struct task_struct
*p
, struct task_struct
*parent
)
1529 __wake_up_sync_key(&parent
->signal
->wait_chldexit
,
1530 TASK_INTERRUPTIBLE
, p
);
1533 static bool is_effectively_child(struct wait_opts
*wo
, bool ptrace
,
1534 struct task_struct
*target
)
1536 struct task_struct
*parent
=
1537 !ptrace
? target
->real_parent
: target
->parent
;
1539 return current
== parent
|| (!(wo
->wo_flags
& __WNOTHREAD
) &&
1540 same_thread_group(current
, parent
));
1544 * Optimization for waiting on PIDTYPE_PID. No need to iterate through child
1545 * and tracee lists to find the target task.
1547 static int do_wait_pid(struct wait_opts
*wo
)
1550 struct task_struct
*target
;
1554 target
= pid_task(wo
->wo_pid
, PIDTYPE_TGID
);
1555 if (target
&& is_effectively_child(wo
, ptrace
, target
)) {
1556 retval
= wait_consider_task(wo
, ptrace
, target
);
1562 target
= pid_task(wo
->wo_pid
, PIDTYPE_PID
);
1563 if (target
&& target
->ptrace
&&
1564 is_effectively_child(wo
, ptrace
, target
)) {
1565 retval
= wait_consider_task(wo
, ptrace
, target
);
1573 static long do_wait(struct wait_opts
*wo
)
1577 trace_sched_process_wait(wo
->wo_pid
);
1579 init_waitqueue_func_entry(&wo
->child_wait
, child_wait_callback
);
1580 wo
->child_wait
.private = current
;
1581 add_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1584 * If there is nothing that can match our criteria, just get out.
1585 * We will clear ->notask_error to zero if we see any child that
1586 * might later match our criteria, even if we are not able to reap
1589 wo
->notask_error
= -ECHILD
;
1590 if ((wo
->wo_type
< PIDTYPE_MAX
) &&
1591 (!wo
->wo_pid
|| !pid_has_task(wo
->wo_pid
, wo
->wo_type
)))
1594 set_current_state(TASK_INTERRUPTIBLE
);
1595 read_lock(&tasklist_lock
);
1597 if (wo
->wo_type
== PIDTYPE_PID
) {
1598 retval
= do_wait_pid(wo
);
1602 struct task_struct
*tsk
= current
;
1605 retval
= do_wait_thread(wo
, tsk
);
1609 retval
= ptrace_do_wait(wo
, tsk
);
1613 if (wo
->wo_flags
& __WNOTHREAD
)
1615 } while_each_thread(current
, tsk
);
1617 read_unlock(&tasklist_lock
);
1620 retval
= wo
->notask_error
;
1621 if (!retval
&& !(wo
->wo_flags
& WNOHANG
)) {
1622 retval
= -ERESTARTSYS
;
1623 if (!signal_pending(current
)) {
1629 __set_current_state(TASK_RUNNING
);
1630 remove_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1634 static long kernel_waitid(int which
, pid_t upid
, struct waitid_info
*infop
,
1635 int options
, struct rusage
*ru
)
1637 struct wait_opts wo
;
1638 struct pid
*pid
= NULL
;
1641 unsigned int f_flags
= 0;
1643 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
|
1644 __WNOTHREAD
|__WCLONE
|__WALL
))
1646 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1658 pid
= find_get_pid(upid
);
1661 type
= PIDTYPE_PGID
;
1666 pid
= find_get_pid(upid
);
1668 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1675 pid
= pidfd_get_pid(upid
, &f_flags
);
1677 return PTR_ERR(pid
);
1686 wo
.wo_flags
= options
;
1689 if (f_flags
& O_NONBLOCK
)
1690 wo
.wo_flags
|= WNOHANG
;
1693 if (!ret
&& !(options
& WNOHANG
) && (f_flags
& O_NONBLOCK
))
1700 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1701 infop
, int, options
, struct rusage __user
*, ru
)
1704 struct waitid_info info
= {.status
= 0};
1705 long err
= kernel_waitid(which
, upid
, &info
, options
, ru
? &r
: NULL
);
1711 if (ru
&& copy_to_user(ru
, &r
, sizeof(struct rusage
)))
1717 if (!user_write_access_begin(infop
, sizeof(*infop
)))
1720 unsafe_put_user(signo
, &infop
->si_signo
, Efault
);
1721 unsafe_put_user(0, &infop
->si_errno
, Efault
);
1722 unsafe_put_user(info
.cause
, &infop
->si_code
, Efault
);
1723 unsafe_put_user(info
.pid
, &infop
->si_pid
, Efault
);
1724 unsafe_put_user(info
.uid
, &infop
->si_uid
, Efault
);
1725 unsafe_put_user(info
.status
, &infop
->si_status
, Efault
);
1726 user_write_access_end();
1729 user_write_access_end();
1733 long kernel_wait4(pid_t upid
, int __user
*stat_addr
, int options
,
1736 struct wait_opts wo
;
1737 struct pid
*pid
= NULL
;
1741 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1742 __WNOTHREAD
|__WCLONE
|__WALL
))
1745 /* -INT_MIN is not defined */
1746 if (upid
== INT_MIN
)
1751 else if (upid
< 0) {
1752 type
= PIDTYPE_PGID
;
1753 pid
= find_get_pid(-upid
);
1754 } else if (upid
== 0) {
1755 type
= PIDTYPE_PGID
;
1756 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1757 } else /* upid > 0 */ {
1759 pid
= find_get_pid(upid
);
1764 wo
.wo_flags
= options
| WEXITED
;
1770 if (ret
> 0 && stat_addr
&& put_user(wo
.wo_stat
, stat_addr
))
1776 int kernel_wait(pid_t pid
, int *stat
)
1778 struct wait_opts wo
= {
1779 .wo_type
= PIDTYPE_PID
,
1780 .wo_pid
= find_get_pid(pid
),
1781 .wo_flags
= WEXITED
,
1786 if (ret
> 0 && wo
.wo_stat
)
1792 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1793 int, options
, struct rusage __user
*, ru
)
1796 long err
= kernel_wait4(upid
, stat_addr
, options
, ru
? &r
: NULL
);
1799 if (ru
&& copy_to_user(ru
, &r
, sizeof(struct rusage
)))
1805 #ifdef __ARCH_WANT_SYS_WAITPID
1808 * sys_waitpid() remains for compatibility. waitpid() should be
1809 * implemented by calling sys_wait4() from libc.a.
1811 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1813 return kernel_wait4(pid
, stat_addr
, options
, NULL
);
1818 #ifdef CONFIG_COMPAT
1819 COMPAT_SYSCALL_DEFINE4(wait4
,
1821 compat_uint_t __user
*, stat_addr
,
1823 struct compat_rusage __user
*, ru
)
1826 long err
= kernel_wait4(pid
, stat_addr
, options
, ru
? &r
: NULL
);
1828 if (ru
&& put_compat_rusage(&r
, ru
))
1834 COMPAT_SYSCALL_DEFINE5(waitid
,
1835 int, which
, compat_pid_t
, pid
,
1836 struct compat_siginfo __user
*, infop
, int, options
,
1837 struct compat_rusage __user
*, uru
)
1840 struct waitid_info info
= {.status
= 0};
1841 long err
= kernel_waitid(which
, pid
, &info
, options
, uru
? &ru
: NULL
);
1847 /* kernel_waitid() overwrites everything in ru */
1848 if (COMPAT_USE_64BIT_TIME
)
1849 err
= copy_to_user(uru
, &ru
, sizeof(ru
));
1851 err
= put_compat_rusage(&ru
, uru
);
1860 if (!user_write_access_begin(infop
, sizeof(*infop
)))
1863 unsafe_put_user(signo
, &infop
->si_signo
, Efault
);
1864 unsafe_put_user(0, &infop
->si_errno
, Efault
);
1865 unsafe_put_user(info
.cause
, &infop
->si_code
, Efault
);
1866 unsafe_put_user(info
.pid
, &infop
->si_pid
, Efault
);
1867 unsafe_put_user(info
.uid
, &infop
->si_uid
, Efault
);
1868 unsafe_put_user(info
.status
, &infop
->si_status
, Efault
);
1869 user_write_access_end();
1872 user_write_access_end();
1878 * thread_group_exited - check that a thread group has exited
1879 * @pid: tgid of thread group to be checked.
1881 * Test if the thread group represented by tgid has exited (all
1882 * threads are zombies, dead or completely gone).
1884 * Return: true if the thread group has exited. false otherwise.
1886 bool thread_group_exited(struct pid
*pid
)
1888 struct task_struct
*task
;
1892 task
= pid_task(pid
, PIDTYPE_PID
);
1894 (READ_ONCE(task
->exit_state
) && thread_group_empty(task
));
1899 EXPORT_SYMBOL(thread_group_exited
);
1901 __weak
void abort(void)
1905 /* if that doesn't kill us, halt */
1906 panic("Oops failed to kill thread");
1908 EXPORT_SYMBOL(abort
);