]>
git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - kernel/exit.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 #include <linux/slab.h>
9 #include <linux/sched/autogroup.h>
10 #include <linux/sched/mm.h>
11 #include <linux/sched/stat.h>
12 #include <linux/interrupt.h>
13 #include <linux/module.h>
14 #include <linux/capability.h>
15 #include <linux/completion.h>
16 #include <linux/personality.h>
17 #include <linux/tty.h>
18 #include <linux/iocontext.h>
19 #include <linux/key.h>
20 #include <linux/cpu.h>
21 #include <linux/acct.h>
22 #include <linux/tsacct_kern.h>
23 #include <linux/file.h>
24 #include <linux/fdtable.h>
25 #include <linux/freezer.h>
26 #include <linux/binfmts.h>
27 #include <linux/nsproxy.h>
28 #include <linux/pid_namespace.h>
29 #include <linux/ptrace.h>
30 #include <linux/profile.h>
31 #include <linux/mount.h>
32 #include <linux/proc_fs.h>
33 #include <linux/kthread.h>
34 #include <linux/mempolicy.h>
35 #include <linux/taskstats_kern.h>
36 #include <linux/delayacct.h>
37 #include <linux/cgroup.h>
38 #include <linux/syscalls.h>
39 #include <linux/signal.h>
40 #include <linux/posix-timers.h>
41 #include <linux/cn_proc.h>
42 #include <linux/mutex.h>
43 #include <linux/futex.h>
44 #include <linux/pipe_fs_i.h>
45 #include <linux/audit.h> /* for audit_free() */
46 #include <linux/resource.h>
47 #include <linux/blkdev.h>
48 #include <linux/task_io_accounting_ops.h>
49 #include <linux/tracehook.h>
50 #include <linux/fs_struct.h>
51 #include <linux/userfaultfd_k.h>
52 #include <linux/init_task.h>
53 #include <linux/perf_event.h>
54 #include <trace/events/sched.h>
55 #include <linux/hw_breakpoint.h>
56 #include <linux/oom.h>
57 #include <linux/writeback.h>
58 #include <linux/shm.h>
59 #include <linux/kcov.h>
60 #include <linux/random.h>
61 #include <linux/rcuwait.h>
63 #include <linux/uaccess.h>
64 #include <asm/unistd.h>
65 #include <asm/pgtable.h>
66 #include <asm/mmu_context.h>
68 static void __unhash_process(struct task_struct
*p
, bool group_dead
)
71 detach_pid(p
, PIDTYPE_PID
);
73 detach_pid(p
, PIDTYPE_PGID
);
74 detach_pid(p
, PIDTYPE_SID
);
76 list_del_rcu(&p
->tasks
);
77 list_del_init(&p
->sibling
);
78 __this_cpu_dec(process_counts
);
80 list_del_rcu(&p
->thread_group
);
81 list_del_rcu(&p
->thread_node
);
85 * This function expects the tasklist_lock write-locked.
87 static void __exit_signal(struct task_struct
*tsk
)
89 struct signal_struct
*sig
= tsk
->signal
;
90 bool group_dead
= thread_group_leader(tsk
);
91 struct sighand_struct
*sighand
;
92 struct tty_struct
*uninitialized_var(tty
);
95 sighand
= rcu_dereference_check(tsk
->sighand
,
96 lockdep_tasklist_lock_is_held());
97 spin_lock(&sighand
->siglock
);
99 #ifdef CONFIG_POSIX_TIMERS
100 posix_cpu_timers_exit(tsk
);
102 posix_cpu_timers_exit_group(tsk
);
105 * This can only happen if the caller is de_thread().
106 * FIXME: this is the temporary hack, we should teach
107 * posix-cpu-timers to handle this case correctly.
109 if (unlikely(has_group_leader_pid(tsk
)))
110 posix_cpu_timers_exit_group(tsk
);
119 * If there is any task waiting for the group exit
122 if (sig
->notify_count
> 0 && !--sig
->notify_count
)
123 wake_up_process(sig
->group_exit_task
);
125 if (tsk
== sig
->curr_target
)
126 sig
->curr_target
= next_thread(tsk
);
129 add_device_randomness((const void*) &tsk
->se
.sum_exec_runtime
,
130 sizeof(unsigned long long));
133 * Accumulate here the counters for all threads as they die. We could
134 * skip the group leader because it is the last user of signal_struct,
135 * but we want to avoid the race with thread_group_cputime() which can
136 * see the empty ->thread_head list.
138 task_cputime(tsk
, &utime
, &stime
);
139 write_seqlock(&sig
->stats_lock
);
142 sig
->gtime
+= task_gtime(tsk
);
143 sig
->min_flt
+= tsk
->min_flt
;
144 sig
->maj_flt
+= tsk
->maj_flt
;
145 sig
->nvcsw
+= tsk
->nvcsw
;
146 sig
->nivcsw
+= tsk
->nivcsw
;
147 sig
->inblock
+= task_io_get_inblock(tsk
);
148 sig
->oublock
+= task_io_get_oublock(tsk
);
149 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
150 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
152 __unhash_process(tsk
, group_dead
);
153 write_sequnlock(&sig
->stats_lock
);
156 * Do this under ->siglock, we can race with another thread
157 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
159 flush_sigqueue(&tsk
->pending
);
161 spin_unlock(&sighand
->siglock
);
163 __cleanup_sighand(sighand
);
164 clear_tsk_thread_flag(tsk
, TIF_SIGPENDING
);
166 flush_sigqueue(&sig
->shared_pending
);
171 static void delayed_put_task_struct(struct rcu_head
*rhp
)
173 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
175 perf_event_delayed_put(tsk
);
176 trace_sched_process_free(tsk
);
177 put_task_struct(tsk
);
181 void release_task(struct task_struct
*p
)
183 struct task_struct
*leader
;
186 /* don't need to get the RCU readlock here - the process is dead and
187 * can't be modifying its own credentials. But shut RCU-lockdep up */
189 atomic_dec(&__task_cred(p
)->user
->processes
);
194 write_lock_irq(&tasklist_lock
);
195 ptrace_release_task(p
);
199 * If we are the last non-leader member of the thread
200 * group, and the leader is zombie, then notify the
201 * group leader's parent process. (if it wants notification.)
204 leader
= p
->group_leader
;
205 if (leader
!= p
&& thread_group_empty(leader
)
206 && leader
->exit_state
== EXIT_ZOMBIE
) {
208 * If we were the last child thread and the leader has
209 * exited already, and the leader's parent ignores SIGCHLD,
210 * then we are the one who should release the leader.
212 zap_leader
= do_notify_parent(leader
, leader
->exit_signal
);
214 leader
->exit_state
= EXIT_DEAD
;
217 write_unlock_irq(&tasklist_lock
);
219 call_rcu(&p
->rcu
, delayed_put_task_struct
);
222 if (unlikely(zap_leader
))
227 * Note that if this function returns a valid task_struct pointer (!NULL)
228 * task->usage must remain >0 for the duration of the RCU critical section.
230 struct task_struct
*task_rcu_dereference(struct task_struct
**ptask
)
232 struct sighand_struct
*sighand
;
233 struct task_struct
*task
;
236 * We need to verify that release_task() was not called and thus
237 * delayed_put_task_struct() can't run and drop the last reference
238 * before rcu_read_unlock(). We check task->sighand != NULL,
239 * but we can read the already freed and reused memory.
242 task
= rcu_dereference(*ptask
);
246 probe_kernel_address(&task
->sighand
, sighand
);
249 * Pairs with atomic_dec_and_test() in put_task_struct(). If this task
250 * was already freed we can not miss the preceding update of this
254 if (unlikely(task
!= READ_ONCE(*ptask
)))
258 * We've re-checked that "task == *ptask", now we have two different
261 * 1. This is actually the same task/task_struct. In this case
262 * sighand != NULL tells us it is still alive.
264 * 2. This is another task which got the same memory for task_struct.
265 * We can't know this of course, and we can not trust
268 * In this case we actually return a random value, but this is
271 * If we return NULL - we can pretend that we actually noticed that
272 * *ptask was updated when the previous task has exited. Or pretend
273 * that probe_slab_address(&sighand) reads NULL.
275 * If we return the new task (because sighand is not NULL for any
276 * reason) - this is fine too. This (new) task can't go away before
279 * And note: We could even eliminate the false positive if re-read
280 * task->sighand once again to avoid the falsely NULL. But this case
281 * is very unlikely so we don't care.
289 void 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_trywake() in the first place. Pairs with set_current_state()
299 * barrier (A) in rcuwait_wait_event().
302 * [S] tsk = current [S] cond = true
309 * Avoid using task_rcu_dereference() magic as long as we are careful,
310 * see comment in rcuwait_wait_event() regarding ->exit_state.
312 task
= rcu_dereference(w
->task
);
314 wake_up_process(task
);
318 struct task_struct
*try_get_task_struct(struct task_struct
**ptask
)
320 struct task_struct
*task
;
323 task
= task_rcu_dereference(ptask
);
325 get_task_struct(task
);
332 * Determine if a process group is "orphaned", according to the POSIX
333 * definition in 2.2.2.52. Orphaned process groups are not to be affected
334 * by terminal-generated stop signals. Newly orphaned process groups are
335 * to receive a SIGHUP and a SIGCONT.
337 * "I ask you, have you ever known what it is to be an orphan?"
339 static int will_become_orphaned_pgrp(struct pid
*pgrp
,
340 struct task_struct
*ignored_task
)
342 struct task_struct
*p
;
344 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
345 if ((p
== ignored_task
) ||
346 (p
->exit_state
&& thread_group_empty(p
)) ||
347 is_global_init(p
->real_parent
))
350 if (task_pgrp(p
->real_parent
) != pgrp
&&
351 task_session(p
->real_parent
) == task_session(p
))
353 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
358 int is_current_pgrp_orphaned(void)
362 read_lock(&tasklist_lock
);
363 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
364 read_unlock(&tasklist_lock
);
369 static bool has_stopped_jobs(struct pid
*pgrp
)
371 struct task_struct
*p
;
373 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
374 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
376 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
382 * Check to see if any process groups have become orphaned as
383 * a result of our exiting, and if they have any stopped jobs,
384 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
387 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
389 struct pid
*pgrp
= task_pgrp(tsk
);
390 struct task_struct
*ignored_task
= tsk
;
393 /* exit: our father is in a different pgrp than
394 * we are and we were the only connection outside.
396 parent
= tsk
->real_parent
;
398 /* reparent: our child is in a different pgrp than
399 * we are, and it was the only connection outside.
403 if (task_pgrp(parent
) != pgrp
&&
404 task_session(parent
) == task_session(tsk
) &&
405 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
406 has_stopped_jobs(pgrp
)) {
407 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
408 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
414 * A task is exiting. If it owned this mm, find a new owner for the mm.
416 void mm_update_next_owner(struct mm_struct
*mm
)
418 struct task_struct
*c
, *g
, *p
= current
;
422 * If the exiting or execing task is not the owner, it's
423 * someone else's problem.
428 * The current owner is exiting/execing and there are no other
429 * candidates. Do not leave the mm pointing to a possibly
430 * freed task structure.
432 if (atomic_read(&mm
->mm_users
) <= 1) {
437 read_lock(&tasklist_lock
);
439 * Search in the children
441 list_for_each_entry(c
, &p
->children
, sibling
) {
443 goto assign_new_owner
;
447 * Search in the siblings
449 list_for_each_entry(c
, &p
->real_parent
->children
, sibling
) {
451 goto assign_new_owner
;
455 * Search through everything else, we should not get here often.
457 for_each_process(g
) {
458 if (g
->flags
& PF_KTHREAD
)
460 for_each_thread(g
, c
) {
462 goto assign_new_owner
;
467 read_unlock(&tasklist_lock
);
469 * We found no owner yet mm_users > 1: this implies that we are
470 * most likely racing with swapoff (try_to_unuse()) or /proc or
471 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
480 * The task_lock protects c->mm from changing.
481 * We always want mm->owner->mm == mm
485 * Delay read_unlock() till we have the task_lock()
486 * to ensure that c does not slip away underneath us
488 read_unlock(&tasklist_lock
);
498 #endif /* CONFIG_MEMCG */
501 * Turn us into a lazy TLB process if we
504 static void exit_mm(void)
506 struct mm_struct
*mm
= current
->mm
;
507 struct core_state
*core_state
;
509 mm_release(current
, mm
);
514 * Serialize with any possible pending coredump.
515 * We must hold mmap_sem around checking core_state
516 * and clearing tsk->mm. The core-inducing thread
517 * will increment ->nr_threads for each thread in the
518 * group with ->mm != NULL.
520 down_read(&mm
->mmap_sem
);
521 core_state
= mm
->core_state
;
523 struct core_thread self
;
525 up_read(&mm
->mmap_sem
);
528 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
530 * Implies mb(), the result of xchg() must be visible
531 * to core_state->dumper.
533 if (atomic_dec_and_test(&core_state
->nr_threads
))
534 complete(&core_state
->startup
);
537 set_current_state(TASK_UNINTERRUPTIBLE
);
538 if (!self
.task
) /* see coredump_finish() */
540 freezable_schedule();
542 __set_current_state(TASK_RUNNING
);
543 down_read(&mm
->mmap_sem
);
546 BUG_ON(mm
!= current
->active_mm
);
547 /* more a memory barrier than a real lock */
550 up_read(&mm
->mmap_sem
);
551 enter_lazy_tlb(mm
, current
);
552 task_unlock(current
);
553 mm_update_next_owner(mm
);
554 userfaultfd_exit(mm
);
556 if (test_thread_flag(TIF_MEMDIE
))
560 static struct task_struct
*find_alive_thread(struct task_struct
*p
)
562 struct task_struct
*t
;
564 for_each_thread(p
, t
) {
565 if (!(t
->flags
& PF_EXITING
))
571 static struct task_struct
*find_child_reaper(struct task_struct
*father
)
572 __releases(&tasklist_lock
)
573 __acquires(&tasklist_lock
)
575 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
576 struct task_struct
*reaper
= pid_ns
->child_reaper
;
578 if (likely(reaper
!= father
))
581 reaper
= find_alive_thread(father
);
583 pid_ns
->child_reaper
= reaper
;
587 write_unlock_irq(&tasklist_lock
);
588 if (unlikely(pid_ns
== &init_pid_ns
)) {
589 panic("Attempted to kill init! exitcode=0x%08x\n",
590 father
->signal
->group_exit_code
?: father
->exit_code
);
592 zap_pid_ns_processes(pid_ns
);
593 write_lock_irq(&tasklist_lock
);
599 * When we die, we re-parent all our children, and try to:
600 * 1. give them to another thread in our thread group, if such a member exists
601 * 2. give it to the first ancestor process which prctl'd itself as a
602 * child_subreaper for its children (like a service manager)
603 * 3. give it to the init process (PID 1) in our pid namespace
605 static struct task_struct
*find_new_reaper(struct task_struct
*father
,
606 struct task_struct
*child_reaper
)
608 struct task_struct
*thread
, *reaper
;
610 thread
= find_alive_thread(father
);
614 if (father
->signal
->has_child_subreaper
) {
615 unsigned int ns_level
= task_pid(father
)->level
;
617 * Find the first ->is_child_subreaper ancestor in our pid_ns.
618 * We can't check reaper != child_reaper to ensure we do not
619 * cross the namespaces, the exiting parent could be injected
620 * by setns() + fork().
621 * We check pid->level, this is slightly more efficient than
622 * task_active_pid_ns(reaper) != task_active_pid_ns(father).
624 for (reaper
= father
->real_parent
;
625 task_pid(reaper
)->level
== ns_level
;
626 reaper
= reaper
->real_parent
) {
627 if (reaper
== &init_task
)
629 if (!reaper
->signal
->is_child_subreaper
)
631 thread
= find_alive_thread(reaper
);
641 * Any that need to be release_task'd are put on the @dead list.
643 static void reparent_leader(struct task_struct
*father
, struct task_struct
*p
,
644 struct list_head
*dead
)
646 if (unlikely(p
->exit_state
== EXIT_DEAD
))
649 /* We don't want people slaying init. */
650 p
->exit_signal
= SIGCHLD
;
652 /* If it has exited notify the new parent about this child's death. */
654 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
655 if (do_notify_parent(p
, p
->exit_signal
)) {
656 p
->exit_state
= EXIT_DEAD
;
657 list_add(&p
->ptrace_entry
, dead
);
661 kill_orphaned_pgrp(p
, father
);
665 * This does two things:
667 * A. Make init inherit all the child processes
668 * B. Check to see if any process groups have become orphaned
669 * as a result of our exiting, and if they have any stopped
670 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
672 static void forget_original_parent(struct task_struct
*father
,
673 struct list_head
*dead
)
675 struct task_struct
*p
, *t
, *reaper
;
677 if (unlikely(!list_empty(&father
->ptraced
)))
678 exit_ptrace(father
, dead
);
680 /* Can drop and reacquire tasklist_lock */
681 reaper
= find_child_reaper(father
);
682 if (list_empty(&father
->children
))
685 reaper
= find_new_reaper(father
, reaper
);
686 list_for_each_entry(p
, &father
->children
, sibling
) {
687 for_each_thread(p
, t
) {
688 t
->real_parent
= reaper
;
689 BUG_ON((!t
->ptrace
) != (t
->parent
== father
));
690 if (likely(!t
->ptrace
))
691 t
->parent
= t
->real_parent
;
692 if (t
->pdeath_signal
)
693 group_send_sig_info(t
->pdeath_signal
,
697 * If this is a threaded reparent there is no need to
698 * notify anyone anything has happened.
700 if (!same_thread_group(reaper
, father
))
701 reparent_leader(father
, p
, dead
);
703 list_splice_tail_init(&father
->children
, &reaper
->children
);
707 * Send signals to all our closest relatives so that they know
708 * to properly mourn us..
710 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
713 struct task_struct
*p
, *n
;
716 write_lock_irq(&tasklist_lock
);
717 forget_original_parent(tsk
, &dead
);
720 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
722 if (unlikely(tsk
->ptrace
)) {
723 int sig
= thread_group_leader(tsk
) &&
724 thread_group_empty(tsk
) &&
725 !ptrace_reparented(tsk
) ?
726 tsk
->exit_signal
: SIGCHLD
;
727 autoreap
= do_notify_parent(tsk
, sig
);
728 } else if (thread_group_leader(tsk
)) {
729 autoreap
= thread_group_empty(tsk
) &&
730 do_notify_parent(tsk
, tsk
->exit_signal
);
735 tsk
->exit_state
= autoreap
? EXIT_DEAD
: EXIT_ZOMBIE
;
736 if (tsk
->exit_state
== EXIT_DEAD
)
737 list_add(&tsk
->ptrace_entry
, &dead
);
739 /* mt-exec, de_thread() is waiting for group leader */
740 if (unlikely(tsk
->signal
->notify_count
< 0))
741 wake_up_process(tsk
->signal
->group_exit_task
);
742 write_unlock_irq(&tasklist_lock
);
744 list_for_each_entry_safe(p
, n
, &dead
, ptrace_entry
) {
745 list_del_init(&p
->ptrace_entry
);
750 #ifdef CONFIG_DEBUG_STACK_USAGE
751 static void check_stack_usage(void)
753 static DEFINE_SPINLOCK(low_water_lock
);
754 static int lowest_to_date
= THREAD_SIZE
;
757 free
= stack_not_used(current
);
759 if (free
>= lowest_to_date
)
762 spin_lock(&low_water_lock
);
763 if (free
< lowest_to_date
) {
764 pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
765 current
->comm
, task_pid_nr(current
), free
);
766 lowest_to_date
= free
;
768 spin_unlock(&low_water_lock
);
771 static inline void check_stack_usage(void) {}
774 void __noreturn
do_exit(long code
)
776 struct task_struct
*tsk
= current
;
778 TASKS_RCU(int tasks_rcu_i
);
780 profile_task_exit(tsk
);
783 WARN_ON(blk_needs_flush_plug(tsk
));
785 if (unlikely(in_interrupt()))
786 panic("Aiee, killing interrupt handler!");
787 if (unlikely(!tsk
->pid
))
788 panic("Attempted to kill the idle task!");
791 * If do_exit is called because this processes oopsed, it's possible
792 * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
793 * continuing. Amongst other possible reasons, this is to prevent
794 * mm_release()->clear_child_tid() from writing to a user-controlled
799 ptrace_event(PTRACE_EVENT_EXIT
, code
);
801 validate_creds_for_do_exit(tsk
);
804 * We're taking recursive faults here in do_exit. Safest is to just
805 * leave this task alone and wait for reboot.
807 if (unlikely(tsk
->flags
& PF_EXITING
)) {
808 pr_alert("Fixing recursive fault but reboot is needed!\n");
810 * We can do this unlocked here. The futex code uses
811 * this flag just to verify whether the pi state
812 * cleanup has been done or not. In the worst case it
813 * loops once more. We pretend that the cleanup was
814 * done as there is no way to return. Either the
815 * OWNER_DIED bit is set by now or we push the blocked
816 * task into the wait for ever nirwana as well.
818 tsk
->flags
|= PF_EXITPIDONE
;
819 set_current_state(TASK_UNINTERRUPTIBLE
);
823 exit_signals(tsk
); /* sets PF_EXITING */
825 * Ensure that all new tsk->pi_lock acquisitions must observe
826 * PF_EXITING. Serializes against futex.c:attach_to_pi_owner().
830 * Ensure that we must observe the pi_state in exit_mm() ->
831 * mm_release() -> exit_pi_state_list().
833 raw_spin_unlock_wait(&tsk
->pi_lock
);
835 if (unlikely(in_atomic())) {
836 pr_info("note: %s[%d] exited with preempt_count %d\n",
837 current
->comm
, task_pid_nr(current
),
839 preempt_count_set(PREEMPT_ENABLED
);
842 /* sync mm's RSS info before statistics gathering */
844 sync_mm_rss(tsk
->mm
);
845 acct_update_integrals(tsk
);
846 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
848 #ifdef CONFIG_POSIX_TIMERS
849 hrtimer_cancel(&tsk
->signal
->real_timer
);
850 exit_itimers(tsk
->signal
);
853 setmax_mm_hiwater_rss(&tsk
->signal
->maxrss
, tsk
->mm
);
855 acct_collect(code
, group_dead
);
860 tsk
->exit_code
= code
;
861 taskstats_exit(tsk
, group_dead
);
867 trace_sched_process_exit(tsk
);
874 disassociate_ctty(1);
875 exit_task_namespaces(tsk
);
880 * Flush inherited counters to the parent - before the parent
881 * gets woken up by child-exit notifications.
883 * because of cgroup mode, must be called before cgroup_exit()
885 perf_event_exit_task(tsk
);
887 sched_autogroup_exit_task(tsk
);
891 * FIXME: do that only when needed, using sched_exit tracepoint
893 flush_ptrace_hw_breakpoint(tsk
);
895 TASKS_RCU(preempt_disable());
896 TASKS_RCU(tasks_rcu_i
= __srcu_read_lock(&tasks_rcu_exit_srcu
));
897 TASKS_RCU(preempt_enable());
898 exit_notify(tsk
, group_dead
);
899 proc_exit_connector(tsk
);
900 mpol_put_task_policy(tsk
);
902 if (unlikely(current
->pi_state_cache
))
903 kfree(current
->pi_state_cache
);
906 * Make sure we are holding no locks:
908 debug_check_no_locks_held();
910 * We can do this unlocked here. The futex code uses this flag
911 * just to verify whether the pi state cleanup has been done
912 * or not. In the worst case it loops once more.
914 tsk
->flags
|= PF_EXITPIDONE
;
917 exit_io_context(tsk
);
919 if (tsk
->splice_pipe
)
920 free_pipe_info(tsk
->splice_pipe
);
922 if (tsk
->task_frag
.page
)
923 put_page(tsk
->task_frag
.page
);
925 validate_creds_for_do_exit(tsk
);
930 __this_cpu_add(dirty_throttle_leaks
, tsk
->nr_dirtied
);
932 TASKS_RCU(__srcu_read_unlock(&tasks_rcu_exit_srcu
, tasks_rcu_i
));
936 EXPORT_SYMBOL_GPL(do_exit
);
938 void complete_and_exit(struct completion
*comp
, long code
)
945 EXPORT_SYMBOL(complete_and_exit
);
947 SYSCALL_DEFINE1(exit
, int, error_code
)
949 do_exit((error_code
&0xff)<<8);
953 * Take down every thread in the group. This is called by fatal signals
954 * as well as by sys_exit_group (below).
957 do_group_exit(int exit_code
)
959 struct signal_struct
*sig
= current
->signal
;
961 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
963 if (signal_group_exit(sig
))
964 exit_code
= sig
->group_exit_code
;
965 else if (!thread_group_empty(current
)) {
966 struct sighand_struct
*const sighand
= current
->sighand
;
968 spin_lock_irq(&sighand
->siglock
);
969 if (signal_group_exit(sig
))
970 /* Another thread got here before we took the lock. */
971 exit_code
= sig
->group_exit_code
;
973 sig
->group_exit_code
= exit_code
;
974 sig
->flags
= SIGNAL_GROUP_EXIT
;
975 zap_other_threads(current
);
977 spin_unlock_irq(&sighand
->siglock
);
985 * this kills every thread in the thread group. Note that any externally
986 * wait4()-ing process will get the correct exit code - even if this
987 * thread is not the thread group leader.
989 SYSCALL_DEFINE1(exit_group
, int, error_code
)
991 do_group_exit((error_code
& 0xff) << 8);
997 enum pid_type wo_type
;
1001 struct siginfo __user
*wo_info
;
1002 int __user
*wo_stat
;
1003 struct rusage __user
*wo_rusage
;
1005 wait_queue_t child_wait
;
1010 struct pid
*task_pid_type(struct task_struct
*task
, enum pid_type type
)
1012 if (type
!= PIDTYPE_PID
)
1013 task
= task
->group_leader
;
1014 return task
->pids
[type
].pid
;
1017 static int eligible_pid(struct wait_opts
*wo
, struct task_struct
*p
)
1019 return wo
->wo_type
== PIDTYPE_MAX
||
1020 task_pid_type(p
, wo
->wo_type
) == wo
->wo_pid
;
1024 eligible_child(struct wait_opts
*wo
, bool ptrace
, struct task_struct
*p
)
1026 if (!eligible_pid(wo
, p
))
1030 * Wait for all children (clone and not) if __WALL is set or
1031 * if it is traced by us.
1033 if (ptrace
|| (wo
->wo_flags
& __WALL
))
1037 * Otherwise, wait for clone children *only* if __WCLONE is set;
1038 * otherwise, wait for non-clone children *only*.
1040 * Note: a "clone" child here is one that reports to its parent
1041 * using a signal other than SIGCHLD, or a non-leader thread which
1042 * we can only see if it is traced by us.
1044 if ((p
->exit_signal
!= SIGCHLD
) ^ !!(wo
->wo_flags
& __WCLONE
))
1050 static int wait_noreap_copyout(struct wait_opts
*wo
, struct task_struct
*p
,
1051 pid_t pid
, uid_t uid
, int why
, int status
)
1053 struct siginfo __user
*infop
;
1054 int retval
= wo
->wo_rusage
1055 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1058 infop
= wo
->wo_info
;
1061 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1063 retval
= put_user(0, &infop
->si_errno
);
1065 retval
= put_user((short)why
, &infop
->si_code
);
1067 retval
= put_user(pid
, &infop
->si_pid
);
1069 retval
= put_user(uid
, &infop
->si_uid
);
1071 retval
= put_user(status
, &infop
->si_status
);
1079 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1080 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1081 * the lock and this task is uninteresting. If we return nonzero, we have
1082 * released the lock and the system call should return.
1084 static int wait_task_zombie(struct wait_opts
*wo
, struct task_struct
*p
)
1086 int state
, retval
, status
;
1087 pid_t pid
= task_pid_vnr(p
);
1088 uid_t uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1089 struct siginfo __user
*infop
;
1091 if (!likely(wo
->wo_flags
& WEXITED
))
1094 if (unlikely(wo
->wo_flags
& WNOWAIT
)) {
1095 int exit_code
= p
->exit_code
;
1099 read_unlock(&tasklist_lock
);
1100 sched_annotate_sleep();
1102 if ((exit_code
& 0x7f) == 0) {
1104 status
= exit_code
>> 8;
1106 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1107 status
= exit_code
& 0x7f;
1109 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, status
);
1112 * Move the task's state to DEAD/TRACE, only one thread can do this.
1114 state
= (ptrace_reparented(p
) && thread_group_leader(p
)) ?
1115 EXIT_TRACE
: EXIT_DEAD
;
1116 if (cmpxchg(&p
->exit_state
, EXIT_ZOMBIE
, state
) != EXIT_ZOMBIE
)
1119 * We own this thread, nobody else can reap it.
1121 read_unlock(&tasklist_lock
);
1122 sched_annotate_sleep();
1125 * Check thread_group_leader() to exclude the traced sub-threads.
1127 if (state
== EXIT_DEAD
&& thread_group_leader(p
)) {
1128 struct signal_struct
*sig
= p
->signal
;
1129 struct signal_struct
*psig
= current
->signal
;
1130 unsigned long maxrss
;
1131 u64 tgutime
, tgstime
;
1134 * The resource counters for the group leader are in its
1135 * own task_struct. Those for dead threads in the group
1136 * are in its signal_struct, as are those for the child
1137 * processes it has previously reaped. All these
1138 * accumulate in the parent's signal_struct c* fields.
1140 * We don't bother to take a lock here to protect these
1141 * p->signal fields because the whole thread group is dead
1142 * and nobody can change them.
1144 * psig->stats_lock also protects us from our sub-theads
1145 * which can reap other children at the same time. Until
1146 * we change k_getrusage()-like users to rely on this lock
1147 * we have to take ->siglock as well.
1149 * We use thread_group_cputime_adjusted() to get times for
1150 * the thread group, which consolidates times for all threads
1151 * in the group including the group leader.
1153 thread_group_cputime_adjusted(p
, &tgutime
, &tgstime
);
1154 spin_lock_irq(¤t
->sighand
->siglock
);
1155 write_seqlock(&psig
->stats_lock
);
1156 psig
->cutime
+= tgutime
+ sig
->cutime
;
1157 psig
->cstime
+= tgstime
+ sig
->cstime
;
1158 psig
->cgtime
+= task_gtime(p
) + sig
->gtime
+ sig
->cgtime
;
1160 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1162 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1164 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1166 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1168 task_io_get_inblock(p
) +
1169 sig
->inblock
+ sig
->cinblock
;
1171 task_io_get_oublock(p
) +
1172 sig
->oublock
+ sig
->coublock
;
1173 maxrss
= max(sig
->maxrss
, sig
->cmaxrss
);
1174 if (psig
->cmaxrss
< maxrss
)
1175 psig
->cmaxrss
= maxrss
;
1176 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1177 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1178 write_sequnlock(&psig
->stats_lock
);
1179 spin_unlock_irq(¤t
->sighand
->siglock
);
1182 retval
= wo
->wo_rusage
1183 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1184 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1185 ? p
->signal
->group_exit_code
: p
->exit_code
;
1186 if (!retval
&& wo
->wo_stat
)
1187 retval
= put_user(status
, wo
->wo_stat
);
1189 infop
= wo
->wo_info
;
1190 if (!retval
&& infop
)
1191 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1192 if (!retval
&& infop
)
1193 retval
= put_user(0, &infop
->si_errno
);
1194 if (!retval
&& infop
) {
1197 if ((status
& 0x7f) == 0) {
1201 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1204 retval
= put_user((short)why
, &infop
->si_code
);
1206 retval
= put_user(status
, &infop
->si_status
);
1208 if (!retval
&& infop
)
1209 retval
= put_user(pid
, &infop
->si_pid
);
1210 if (!retval
&& infop
)
1211 retval
= put_user(uid
, &infop
->si_uid
);
1215 if (state
== EXIT_TRACE
) {
1216 write_lock_irq(&tasklist_lock
);
1217 /* We dropped tasklist, ptracer could die and untrace */
1220 /* If parent wants a zombie, don't release it now */
1221 state
= EXIT_ZOMBIE
;
1222 if (do_notify_parent(p
, p
->exit_signal
))
1224 p
->exit_state
= state
;
1225 write_unlock_irq(&tasklist_lock
);
1227 if (state
== EXIT_DEAD
)
1233 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1236 if (task_is_traced(p
) && !(p
->jobctl
& JOBCTL_LISTENING
))
1237 return &p
->exit_code
;
1239 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1240 return &p
->signal
->group_exit_code
;
1246 * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
1248 * @ptrace: is the wait for ptrace
1249 * @p: task to wait for
1251 * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
1254 * read_lock(&tasklist_lock), which is released if return value is
1255 * non-zero. Also, grabs and releases @p->sighand->siglock.
1258 * 0 if wait condition didn't exist and search for other wait conditions
1259 * should continue. Non-zero return, -errno on failure and @p's pid on
1260 * success, implies that tasklist_lock is released and wait condition
1261 * search should terminate.
1263 static int wait_task_stopped(struct wait_opts
*wo
,
1264 int ptrace
, struct task_struct
*p
)
1266 struct siginfo __user
*infop
;
1267 int retval
, exit_code
, *p_code
, why
;
1268 uid_t uid
= 0; /* unneeded, required by compiler */
1272 * Traditionally we see ptrace'd stopped tasks regardless of options.
1274 if (!ptrace
&& !(wo
->wo_flags
& WUNTRACED
))
1277 if (!task_stopped_code(p
, ptrace
))
1281 spin_lock_irq(&p
->sighand
->siglock
);
1283 p_code
= task_stopped_code(p
, ptrace
);
1284 if (unlikely(!p_code
))
1287 exit_code
= *p_code
;
1291 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1294 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1296 spin_unlock_irq(&p
->sighand
->siglock
);
1301 * Now we are pretty sure this task is interesting.
1302 * Make sure it doesn't get reaped out from under us while we
1303 * give up the lock and then examine it below. We don't want to
1304 * keep holding onto the tasklist_lock while we call getrusage and
1305 * possibly take page faults for user memory.
1308 pid
= task_pid_vnr(p
);
1309 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1310 read_unlock(&tasklist_lock
);
1311 sched_annotate_sleep();
1313 if (unlikely(wo
->wo_flags
& WNOWAIT
))
1314 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, exit_code
);
1316 retval
= wo
->wo_rusage
1317 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1318 if (!retval
&& wo
->wo_stat
)
1319 retval
= put_user((exit_code
<< 8) | 0x7f, wo
->wo_stat
);
1321 infop
= wo
->wo_info
;
1322 if (!retval
&& infop
)
1323 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1324 if (!retval
&& infop
)
1325 retval
= put_user(0, &infop
->si_errno
);
1326 if (!retval
&& infop
)
1327 retval
= put_user((short)why
, &infop
->si_code
);
1328 if (!retval
&& infop
)
1329 retval
= put_user(exit_code
, &infop
->si_status
);
1330 if (!retval
&& infop
)
1331 retval
= put_user(pid
, &infop
->si_pid
);
1332 if (!retval
&& infop
)
1333 retval
= put_user(uid
, &infop
->si_uid
);
1343 * Handle do_wait work for one task in a live, non-stopped state.
1344 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1345 * the lock and this task is uninteresting. If we return nonzero, we have
1346 * released the lock and the system call should return.
1348 static int wait_task_continued(struct wait_opts
*wo
, struct task_struct
*p
)
1354 if (!unlikely(wo
->wo_flags
& WCONTINUED
))
1357 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1360 spin_lock_irq(&p
->sighand
->siglock
);
1361 /* Re-check with the lock held. */
1362 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1363 spin_unlock_irq(&p
->sighand
->siglock
);
1366 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1367 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1368 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1369 spin_unlock_irq(&p
->sighand
->siglock
);
1371 pid
= task_pid_vnr(p
);
1373 read_unlock(&tasklist_lock
);
1374 sched_annotate_sleep();
1377 retval
= wo
->wo_rusage
1378 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1380 if (!retval
&& wo
->wo_stat
)
1381 retval
= put_user(0xffff, wo
->wo_stat
);
1385 retval
= wait_noreap_copyout(wo
, p
, pid
, uid
,
1386 CLD_CONTINUED
, SIGCONT
);
1387 BUG_ON(retval
== 0);
1394 * Consider @p for a wait by @parent.
1396 * -ECHILD should be in ->notask_error before the first call.
1397 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1398 * Returns zero if the search for a child should continue;
1399 * then ->notask_error is 0 if @p is an eligible child,
1402 static int wait_consider_task(struct wait_opts
*wo
, int ptrace
,
1403 struct task_struct
*p
)
1406 * We can race with wait_task_zombie() from another thread.
1407 * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
1408 * can't confuse the checks below.
1410 int exit_state
= ACCESS_ONCE(p
->exit_state
);
1413 if (unlikely(exit_state
== EXIT_DEAD
))
1416 ret
= eligible_child(wo
, ptrace
, p
);
1420 if (unlikely(exit_state
== EXIT_TRACE
)) {
1422 * ptrace == 0 means we are the natural parent. In this case
1423 * we should clear notask_error, debugger will notify us.
1425 if (likely(!ptrace
))
1426 wo
->notask_error
= 0;
1430 if (likely(!ptrace
) && unlikely(p
->ptrace
)) {
1432 * If it is traced by its real parent's group, just pretend
1433 * the caller is ptrace_do_wait() and reap this child if it
1436 * This also hides group stop state from real parent; otherwise
1437 * a single stop can be reported twice as group and ptrace stop.
1438 * If a ptracer wants to distinguish these two events for its
1439 * own children it should create a separate process which takes
1440 * the role of real parent.
1442 if (!ptrace_reparented(p
))
1447 if (exit_state
== EXIT_ZOMBIE
) {
1448 /* we don't reap group leaders with subthreads */
1449 if (!delay_group_leader(p
)) {
1451 * A zombie ptracee is only visible to its ptracer.
1452 * Notification and reaping will be cascaded to the
1453 * real parent when the ptracer detaches.
1455 if (unlikely(ptrace
) || likely(!p
->ptrace
))
1456 return wait_task_zombie(wo
, p
);
1460 * Allow access to stopped/continued state via zombie by
1461 * falling through. Clearing of notask_error is complex.
1465 * If WEXITED is set, notask_error should naturally be
1466 * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
1467 * so, if there are live subthreads, there are events to
1468 * wait for. If all subthreads are dead, it's still safe
1469 * to clear - this function will be called again in finite
1470 * amount time once all the subthreads are released and
1471 * will then return without clearing.
1475 * Stopped state is per-task and thus can't change once the
1476 * target task dies. Only continued and exited can happen.
1477 * Clear notask_error if WCONTINUED | WEXITED.
1479 if (likely(!ptrace
) || (wo
->wo_flags
& (WCONTINUED
| WEXITED
)))
1480 wo
->notask_error
= 0;
1483 * @p is alive and it's gonna stop, continue or exit, so
1484 * there always is something to wait for.
1486 wo
->notask_error
= 0;
1490 * Wait for stopped. Depending on @ptrace, different stopped state
1491 * is used and the two don't interact with each other.
1493 ret
= wait_task_stopped(wo
, ptrace
, p
);
1498 * Wait for continued. There's only one continued state and the
1499 * ptracer can consume it which can confuse the real parent. Don't
1500 * use WCONTINUED from ptracer. You don't need or want it.
1502 return wait_task_continued(wo
, p
);
1506 * Do the work of do_wait() for one thread in the group, @tsk.
1508 * -ECHILD should be in ->notask_error before the first call.
1509 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1510 * Returns zero if the search for a child should continue; then
1511 * ->notask_error is 0 if there were any eligible children,
1514 static int do_wait_thread(struct wait_opts
*wo
, struct task_struct
*tsk
)
1516 struct task_struct
*p
;
1518 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1519 int ret
= wait_consider_task(wo
, 0, p
);
1528 static int ptrace_do_wait(struct wait_opts
*wo
, struct task_struct
*tsk
)
1530 struct task_struct
*p
;
1532 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1533 int ret
= wait_consider_task(wo
, 1, p
);
1542 static int child_wait_callback(wait_queue_t
*wait
, unsigned mode
,
1543 int sync
, void *key
)
1545 struct wait_opts
*wo
= container_of(wait
, struct wait_opts
,
1547 struct task_struct
*p
= key
;
1549 if (!eligible_pid(wo
, p
))
1552 if ((wo
->wo_flags
& __WNOTHREAD
) && wait
->private != p
->parent
)
1555 return default_wake_function(wait
, mode
, sync
, key
);
1558 void __wake_up_parent(struct task_struct
*p
, struct task_struct
*parent
)
1560 __wake_up_sync_key(&parent
->signal
->wait_chldexit
,
1561 TASK_INTERRUPTIBLE
, 1, p
);
1564 static long do_wait(struct wait_opts
*wo
)
1566 struct task_struct
*tsk
;
1569 trace_sched_process_wait(wo
->wo_pid
);
1571 init_waitqueue_func_entry(&wo
->child_wait
, child_wait_callback
);
1572 wo
->child_wait
.private = current
;
1573 add_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1576 * If there is nothing that can match our criteria, just get out.
1577 * We will clear ->notask_error to zero if we see any child that
1578 * might later match our criteria, even if we are not able to reap
1581 wo
->notask_error
= -ECHILD
;
1582 if ((wo
->wo_type
< PIDTYPE_MAX
) &&
1583 (!wo
->wo_pid
|| hlist_empty(&wo
->wo_pid
->tasks
[wo
->wo_type
])))
1586 set_current_state(TASK_INTERRUPTIBLE
);
1587 read_lock(&tasklist_lock
);
1590 retval
= do_wait_thread(wo
, tsk
);
1594 retval
= ptrace_do_wait(wo
, tsk
);
1598 if (wo
->wo_flags
& __WNOTHREAD
)
1600 } while_each_thread(current
, tsk
);
1601 read_unlock(&tasklist_lock
);
1604 retval
= wo
->notask_error
;
1605 if (!retval
&& !(wo
->wo_flags
& WNOHANG
)) {
1606 retval
= -ERESTARTSYS
;
1607 if (!signal_pending(current
)) {
1613 __set_current_state(TASK_RUNNING
);
1614 remove_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1618 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1619 infop
, int, options
, struct rusage __user
*, ru
)
1621 struct wait_opts wo
;
1622 struct pid
*pid
= NULL
;
1626 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
|
1627 __WNOTHREAD
|__WCLONE
|__WALL
))
1629 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1642 type
= PIDTYPE_PGID
;
1650 if (type
< PIDTYPE_MAX
)
1651 pid
= find_get_pid(upid
);
1655 wo
.wo_flags
= options
;
1665 * For a WNOHANG return, clear out all the fields
1666 * we would set so the user can easily tell the
1670 ret
= put_user(0, &infop
->si_signo
);
1672 ret
= put_user(0, &infop
->si_errno
);
1674 ret
= put_user(0, &infop
->si_code
);
1676 ret
= put_user(0, &infop
->si_pid
);
1678 ret
= put_user(0, &infop
->si_uid
);
1680 ret
= put_user(0, &infop
->si_status
);
1687 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1688 int, options
, struct rusage __user
*, ru
)
1690 struct wait_opts wo
;
1691 struct pid
*pid
= NULL
;
1695 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1696 __WNOTHREAD
|__WCLONE
|__WALL
))
1701 else if (upid
< 0) {
1702 type
= PIDTYPE_PGID
;
1703 pid
= find_get_pid(-upid
);
1704 } else if (upid
== 0) {
1705 type
= PIDTYPE_PGID
;
1706 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1707 } else /* upid > 0 */ {
1709 pid
= find_get_pid(upid
);
1714 wo
.wo_flags
= options
| WEXITED
;
1716 wo
.wo_stat
= stat_addr
;
1724 #ifdef __ARCH_WANT_SYS_WAITPID
1727 * sys_waitpid() remains for compatibility. waitpid() should be
1728 * implemented by calling sys_wait4() from libc.a.
1730 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1732 return sys_wait4(pid
, stat_addr
, options
, NULL
);