]>
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/sched/task.h>
13 #include <linux/sched/task_stack.h>
14 #include <linux/sched/cputime.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/capability.h>
18 #include <linux/completion.h>
19 #include <linux/personality.h>
20 #include <linux/tty.h>
21 #include <linux/iocontext.h>
22 #include <linux/key.h>
23 #include <linux/cpu.h>
24 #include <linux/acct.h>
25 #include <linux/tsacct_kern.h>
26 #include <linux/file.h>
27 #include <linux/fdtable.h>
28 #include <linux/freezer.h>
29 #include <linux/binfmts.h>
30 #include <linux/nsproxy.h>
31 #include <linux/pid_namespace.h>
32 #include <linux/ptrace.h>
33 #include <linux/profile.h>
34 #include <linux/mount.h>
35 #include <linux/proc_fs.h>
36 #include <linux/kthread.h>
37 #include <linux/mempolicy.h>
38 #include <linux/taskstats_kern.h>
39 #include <linux/delayacct.h>
40 #include <linux/cgroup.h>
41 #include <linux/syscalls.h>
42 #include <linux/signal.h>
43 #include <linux/posix-timers.h>
44 #include <linux/cn_proc.h>
45 #include <linux/mutex.h>
46 #include <linux/futex.h>
47 #include <linux/pipe_fs_i.h>
48 #include <linux/audit.h> /* for audit_free() */
49 #include <linux/resource.h>
50 #include <linux/blkdev.h>
51 #include <linux/task_io_accounting_ops.h>
52 #include <linux/tracehook.h>
53 #include <linux/fs_struct.h>
54 #include <linux/userfaultfd_k.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/random.h>
64 #include <linux/rcuwait.h>
66 #include <linux/uaccess.h>
67 #include <asm/unistd.h>
68 #include <asm/pgtable.h>
69 #include <asm/mmu_context.h>
71 static void __unhash_process(struct task_struct
*p
, bool group_dead
)
74 detach_pid(p
, PIDTYPE_PID
);
76 detach_pid(p
, PIDTYPE_PGID
);
77 detach_pid(p
, PIDTYPE_SID
);
79 list_del_rcu(&p
->tasks
);
80 list_del_init(&p
->sibling
);
81 __this_cpu_dec(process_counts
);
83 list_del_rcu(&p
->thread_group
);
84 list_del_rcu(&p
->thread_node
);
88 * This function expects the tasklist_lock write-locked.
90 static void __exit_signal(struct task_struct
*tsk
)
92 struct signal_struct
*sig
= tsk
->signal
;
93 bool group_dead
= thread_group_leader(tsk
);
94 struct sighand_struct
*sighand
;
95 struct tty_struct
*uninitialized_var(tty
);
98 sighand
= rcu_dereference_check(tsk
->sighand
,
99 lockdep_tasklist_lock_is_held());
100 spin_lock(&sighand
->siglock
);
102 #ifdef CONFIG_POSIX_TIMERS
103 posix_cpu_timers_exit(tsk
);
105 posix_cpu_timers_exit_group(tsk
);
108 * This can only happen if the caller is de_thread().
109 * FIXME: this is the temporary hack, we should teach
110 * posix-cpu-timers to handle this case correctly.
112 if (unlikely(has_group_leader_pid(tsk
)))
113 posix_cpu_timers_exit_group(tsk
);
122 * If there is any task waiting for the group exit
125 if (sig
->notify_count
> 0 && !--sig
->notify_count
)
126 wake_up_process(sig
->group_exit_task
);
128 if (tsk
== sig
->curr_target
)
129 sig
->curr_target
= next_thread(tsk
);
132 add_device_randomness((const void*) &tsk
->se
.sum_exec_runtime
,
133 sizeof(unsigned long long));
136 * Accumulate here the counters for all threads as they die. We could
137 * skip the group leader because it is the last user of signal_struct,
138 * but we want to avoid the race with thread_group_cputime() which can
139 * see the empty ->thread_head list.
141 task_cputime(tsk
, &utime
, &stime
);
142 write_seqlock(&sig
->stats_lock
);
145 sig
->gtime
+= task_gtime(tsk
);
146 sig
->min_flt
+= tsk
->min_flt
;
147 sig
->maj_flt
+= tsk
->maj_flt
;
148 sig
->nvcsw
+= tsk
->nvcsw
;
149 sig
->nivcsw
+= tsk
->nivcsw
;
150 sig
->inblock
+= task_io_get_inblock(tsk
);
151 sig
->oublock
+= task_io_get_oublock(tsk
);
152 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
153 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
155 __unhash_process(tsk
, group_dead
);
156 write_sequnlock(&sig
->stats_lock
);
159 * Do this under ->siglock, we can race with another thread
160 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
162 flush_sigqueue(&tsk
->pending
);
164 spin_unlock(&sighand
->siglock
);
166 __cleanup_sighand(sighand
);
167 clear_tsk_thread_flag(tsk
, TIF_SIGPENDING
);
169 flush_sigqueue(&sig
->shared_pending
);
174 static void delayed_put_task_struct(struct rcu_head
*rhp
)
176 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
178 perf_event_delayed_put(tsk
);
179 trace_sched_process_free(tsk
);
180 put_task_struct(tsk
);
184 void release_task(struct task_struct
*p
)
186 struct task_struct
*leader
;
189 /* don't need to get the RCU readlock here - the process is dead and
190 * can't be modifying its own credentials. But shut RCU-lockdep up */
192 atomic_dec(&__task_cred(p
)->user
->processes
);
197 write_lock_irq(&tasklist_lock
);
198 ptrace_release_task(p
);
202 * If we are the last non-leader member of the thread
203 * group, and the leader is zombie, then notify the
204 * group leader's parent process. (if it wants notification.)
207 leader
= p
->group_leader
;
208 if (leader
!= p
&& thread_group_empty(leader
)
209 && leader
->exit_state
== EXIT_ZOMBIE
) {
211 * If we were the last child thread and the leader has
212 * exited already, and the leader's parent ignores SIGCHLD,
213 * then we are the one who should release the leader.
215 zap_leader
= do_notify_parent(leader
, leader
->exit_signal
);
217 leader
->exit_state
= EXIT_DEAD
;
220 write_unlock_irq(&tasklist_lock
);
222 call_rcu(&p
->rcu
, delayed_put_task_struct
);
225 if (unlikely(zap_leader
))
230 * Note that if this function returns a valid task_struct pointer (!NULL)
231 * task->usage must remain >0 for the duration of the RCU critical section.
233 struct task_struct
*task_rcu_dereference(struct task_struct
**ptask
)
235 struct sighand_struct
*sighand
;
236 struct task_struct
*task
;
239 * We need to verify that release_task() was not called and thus
240 * delayed_put_task_struct() can't run and drop the last reference
241 * before rcu_read_unlock(). We check task->sighand != NULL,
242 * but we can read the already freed and reused memory.
245 task
= rcu_dereference(*ptask
);
249 probe_kernel_address(&task
->sighand
, sighand
);
252 * Pairs with atomic_dec_and_test() in put_task_struct(). If this task
253 * was already freed we can not miss the preceding update of this
257 if (unlikely(task
!= READ_ONCE(*ptask
)))
261 * We've re-checked that "task == *ptask", now we have two different
264 * 1. This is actually the same task/task_struct. In this case
265 * sighand != NULL tells us it is still alive.
267 * 2. This is another task which got the same memory for task_struct.
268 * We can't know this of course, and we can not trust
271 * In this case we actually return a random value, but this is
274 * If we return NULL - we can pretend that we actually noticed that
275 * *ptask was updated when the previous task has exited. Or pretend
276 * that probe_slab_address(&sighand) reads NULL.
278 * If we return the new task (because sighand is not NULL for any
279 * reason) - this is fine too. This (new) task can't go away before
282 * And note: We could even eliminate the false positive if re-read
283 * task->sighand once again to avoid the falsely NULL. But this case
284 * is very unlikely so we don't care.
292 void rcuwait_wake_up(struct rcuwait
*w
)
294 struct task_struct
*task
;
299 * Order condition vs @task, such that everything prior to the load
300 * of @task is visible. This is the condition as to why the user called
301 * rcuwait_trywake() in the first place. Pairs with set_current_state()
302 * barrier (A) in rcuwait_wait_event().
305 * [S] tsk = current [S] cond = true
312 * Avoid using task_rcu_dereference() magic as long as we are careful,
313 * see comment in rcuwait_wait_event() regarding ->exit_state.
315 task
= rcu_dereference(w
->task
);
317 wake_up_process(task
);
321 struct task_struct
*try_get_task_struct(struct task_struct
**ptask
)
323 struct task_struct
*task
;
326 task
= task_rcu_dereference(ptask
);
328 get_task_struct(task
);
335 * Determine if a process group is "orphaned", according to the POSIX
336 * definition in 2.2.2.52. Orphaned process groups are not to be affected
337 * by terminal-generated stop signals. Newly orphaned process groups are
338 * to receive a SIGHUP and a SIGCONT.
340 * "I ask you, have you ever known what it is to be an orphan?"
342 static int will_become_orphaned_pgrp(struct pid
*pgrp
,
343 struct task_struct
*ignored_task
)
345 struct task_struct
*p
;
347 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
348 if ((p
== ignored_task
) ||
349 (p
->exit_state
&& thread_group_empty(p
)) ||
350 is_global_init(p
->real_parent
))
353 if (task_pgrp(p
->real_parent
) != pgrp
&&
354 task_session(p
->real_parent
) == task_session(p
))
356 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
361 int is_current_pgrp_orphaned(void)
365 read_lock(&tasklist_lock
);
366 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
367 read_unlock(&tasklist_lock
);
372 static bool has_stopped_jobs(struct pid
*pgrp
)
374 struct task_struct
*p
;
376 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
377 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
379 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
385 * Check to see if any process groups have become orphaned as
386 * a result of our exiting, and if they have any stopped jobs,
387 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
390 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
392 struct pid
*pgrp
= task_pgrp(tsk
);
393 struct task_struct
*ignored_task
= tsk
;
396 /* exit: our father is in a different pgrp than
397 * we are and we were the only connection outside.
399 parent
= tsk
->real_parent
;
401 /* reparent: our child is in a different pgrp than
402 * we are, and it was the only connection outside.
406 if (task_pgrp(parent
) != pgrp
&&
407 task_session(parent
) == task_session(tsk
) &&
408 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
409 has_stopped_jobs(pgrp
)) {
410 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
411 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
417 * A task is exiting. If it owned this mm, find a new owner for the mm.
419 void mm_update_next_owner(struct mm_struct
*mm
)
421 struct task_struct
*c
, *g
, *p
= current
;
425 * If the exiting or execing task is not the owner, it's
426 * someone else's problem.
431 * The current owner is exiting/execing and there are no other
432 * candidates. Do not leave the mm pointing to a possibly
433 * freed task structure.
435 if (atomic_read(&mm
->mm_users
) <= 1) {
440 read_lock(&tasklist_lock
);
442 * Search in the children
444 list_for_each_entry(c
, &p
->children
, sibling
) {
446 goto assign_new_owner
;
450 * Search in the siblings
452 list_for_each_entry(c
, &p
->real_parent
->children
, sibling
) {
454 goto assign_new_owner
;
458 * Search through everything else, we should not get here often.
460 for_each_process(g
) {
461 if (g
->flags
& PF_KTHREAD
)
463 for_each_thread(g
, c
) {
465 goto assign_new_owner
;
470 read_unlock(&tasklist_lock
);
472 * We found no owner yet mm_users > 1: this implies that we are
473 * most likely racing with swapoff (try_to_unuse()) or /proc or
474 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
483 * The task_lock protects c->mm from changing.
484 * We always want mm->owner->mm == mm
488 * Delay read_unlock() till we have the task_lock()
489 * to ensure that c does not slip away underneath us
491 read_unlock(&tasklist_lock
);
501 #endif /* CONFIG_MEMCG */
504 * Turn us into a lazy TLB process if we
507 static void exit_mm(void)
509 struct mm_struct
*mm
= current
->mm
;
510 struct core_state
*core_state
;
512 mm_release(current
, mm
);
517 * Serialize with any possible pending coredump.
518 * We must hold mmap_sem around checking core_state
519 * and clearing tsk->mm. The core-inducing thread
520 * will increment ->nr_threads for each thread in the
521 * group with ->mm != NULL.
523 down_read(&mm
->mmap_sem
);
524 core_state
= mm
->core_state
;
526 struct core_thread self
;
528 up_read(&mm
->mmap_sem
);
531 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
533 * Implies mb(), the result of xchg() must be visible
534 * to core_state->dumper.
536 if (atomic_dec_and_test(&core_state
->nr_threads
))
537 complete(&core_state
->startup
);
540 set_current_state(TASK_UNINTERRUPTIBLE
);
541 if (!self
.task
) /* see coredump_finish() */
543 freezable_schedule();
545 __set_current_state(TASK_RUNNING
);
546 down_read(&mm
->mmap_sem
);
549 BUG_ON(mm
!= current
->active_mm
);
550 /* more a memory barrier than a real lock */
553 up_read(&mm
->mmap_sem
);
554 enter_lazy_tlb(mm
, current
);
555 task_unlock(current
);
556 mm_update_next_owner(mm
);
557 userfaultfd_exit(mm
);
559 if (test_thread_flag(TIF_MEMDIE
))
563 static struct task_struct
*find_alive_thread(struct task_struct
*p
)
565 struct task_struct
*t
;
567 for_each_thread(p
, t
) {
568 if (!(t
->flags
& PF_EXITING
))
574 static struct task_struct
*find_child_reaper(struct task_struct
*father
)
575 __releases(&tasklist_lock
)
576 __acquires(&tasklist_lock
)
578 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
579 struct task_struct
*reaper
= pid_ns
->child_reaper
;
581 if (likely(reaper
!= father
))
584 reaper
= find_alive_thread(father
);
586 pid_ns
->child_reaper
= reaper
;
590 write_unlock_irq(&tasklist_lock
);
591 if (unlikely(pid_ns
== &init_pid_ns
)) {
592 panic("Attempted to kill init! exitcode=0x%08x\n",
593 father
->signal
->group_exit_code
?: father
->exit_code
);
595 zap_pid_ns_processes(pid_ns
);
596 write_lock_irq(&tasklist_lock
);
602 * When we die, we re-parent all our children, and try to:
603 * 1. give them to another thread in our thread group, if such a member exists
604 * 2. give it to the first ancestor process which prctl'd itself as a
605 * child_subreaper for its children (like a service manager)
606 * 3. give it to the init process (PID 1) in our pid namespace
608 static struct task_struct
*find_new_reaper(struct task_struct
*father
,
609 struct task_struct
*child_reaper
)
611 struct task_struct
*thread
, *reaper
;
613 thread
= find_alive_thread(father
);
617 if (father
->signal
->has_child_subreaper
) {
618 unsigned int ns_level
= task_pid(father
)->level
;
620 * Find the first ->is_child_subreaper ancestor in our pid_ns.
621 * We can't check reaper != child_reaper to ensure we do not
622 * cross the namespaces, the exiting parent could be injected
623 * by setns() + fork().
624 * We check pid->level, this is slightly more efficient than
625 * task_active_pid_ns(reaper) != task_active_pid_ns(father).
627 for (reaper
= father
->real_parent
;
628 task_pid(reaper
)->level
== ns_level
;
629 reaper
= reaper
->real_parent
) {
630 if (reaper
== &init_task
)
632 if (!reaper
->signal
->is_child_subreaper
)
634 thread
= find_alive_thread(reaper
);
644 * Any that need to be release_task'd are put on the @dead list.
646 static void reparent_leader(struct task_struct
*father
, struct task_struct
*p
,
647 struct list_head
*dead
)
649 if (unlikely(p
->exit_state
== EXIT_DEAD
))
652 /* We don't want people slaying init. */
653 p
->exit_signal
= SIGCHLD
;
655 /* If it has exited notify the new parent about this child's death. */
657 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
658 if (do_notify_parent(p
, p
->exit_signal
)) {
659 p
->exit_state
= EXIT_DEAD
;
660 list_add(&p
->ptrace_entry
, dead
);
664 kill_orphaned_pgrp(p
, father
);
668 * This does two things:
670 * A. Make init inherit all the child processes
671 * B. Check to see if any process groups have become orphaned
672 * as a result of our exiting, and if they have any stopped
673 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
675 static void forget_original_parent(struct task_struct
*father
,
676 struct list_head
*dead
)
678 struct task_struct
*p
, *t
, *reaper
;
680 if (unlikely(!list_empty(&father
->ptraced
)))
681 exit_ptrace(father
, dead
);
683 /* Can drop and reacquire tasklist_lock */
684 reaper
= find_child_reaper(father
);
685 if (list_empty(&father
->children
))
688 reaper
= find_new_reaper(father
, reaper
);
689 list_for_each_entry(p
, &father
->children
, sibling
) {
690 for_each_thread(p
, t
) {
691 t
->real_parent
= reaper
;
692 BUG_ON((!t
->ptrace
) != (t
->parent
== father
));
693 if (likely(!t
->ptrace
))
694 t
->parent
= t
->real_parent
;
695 if (t
->pdeath_signal
)
696 group_send_sig_info(t
->pdeath_signal
,
700 * If this is a threaded reparent there is no need to
701 * notify anyone anything has happened.
703 if (!same_thread_group(reaper
, father
))
704 reparent_leader(father
, p
, dead
);
706 list_splice_tail_init(&father
->children
, &reaper
->children
);
710 * Send signals to all our closest relatives so that they know
711 * to properly mourn us..
713 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
716 struct task_struct
*p
, *n
;
719 write_lock_irq(&tasklist_lock
);
720 forget_original_parent(tsk
, &dead
);
723 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
725 if (unlikely(tsk
->ptrace
)) {
726 int sig
= thread_group_leader(tsk
) &&
727 thread_group_empty(tsk
) &&
728 !ptrace_reparented(tsk
) ?
729 tsk
->exit_signal
: SIGCHLD
;
730 autoreap
= do_notify_parent(tsk
, sig
);
731 } else if (thread_group_leader(tsk
)) {
732 autoreap
= thread_group_empty(tsk
) &&
733 do_notify_parent(tsk
, tsk
->exit_signal
);
738 tsk
->exit_state
= autoreap
? EXIT_DEAD
: EXIT_ZOMBIE
;
739 if (tsk
->exit_state
== EXIT_DEAD
)
740 list_add(&tsk
->ptrace_entry
, &dead
);
742 /* mt-exec, de_thread() is waiting for group leader */
743 if (unlikely(tsk
->signal
->notify_count
< 0))
744 wake_up_process(tsk
->signal
->group_exit_task
);
745 write_unlock_irq(&tasklist_lock
);
747 list_for_each_entry_safe(p
, n
, &dead
, ptrace_entry
) {
748 list_del_init(&p
->ptrace_entry
);
753 #ifdef CONFIG_DEBUG_STACK_USAGE
754 static void check_stack_usage(void)
756 static DEFINE_SPINLOCK(low_water_lock
);
757 static int lowest_to_date
= THREAD_SIZE
;
760 free
= stack_not_used(current
);
762 if (free
>= lowest_to_date
)
765 spin_lock(&low_water_lock
);
766 if (free
< lowest_to_date
) {
767 pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
768 current
->comm
, task_pid_nr(current
), free
);
769 lowest_to_date
= free
;
771 spin_unlock(&low_water_lock
);
774 static inline void check_stack_usage(void) {}
777 void __noreturn
do_exit(long code
)
779 struct task_struct
*tsk
= current
;
781 TASKS_RCU(int tasks_rcu_i
);
783 profile_task_exit(tsk
);
786 WARN_ON(blk_needs_flush_plug(tsk
));
788 if (unlikely(in_interrupt()))
789 panic("Aiee, killing interrupt handler!");
790 if (unlikely(!tsk
->pid
))
791 panic("Attempted to kill the idle task!");
794 * If do_exit is called because this processes oopsed, it's possible
795 * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
796 * continuing. Amongst other possible reasons, this is to prevent
797 * mm_release()->clear_child_tid() from writing to a user-controlled
802 ptrace_event(PTRACE_EVENT_EXIT
, code
);
804 validate_creds_for_do_exit(tsk
);
807 * We're taking recursive faults here in do_exit. Safest is to just
808 * leave this task alone and wait for reboot.
810 if (unlikely(tsk
->flags
& PF_EXITING
)) {
811 pr_alert("Fixing recursive fault but reboot is needed!\n");
813 * We can do this unlocked here. The futex code uses
814 * this flag just to verify whether the pi state
815 * cleanup has been done or not. In the worst case it
816 * loops once more. We pretend that the cleanup was
817 * done as there is no way to return. Either the
818 * OWNER_DIED bit is set by now or we push the blocked
819 * task into the wait for ever nirwana as well.
821 tsk
->flags
|= PF_EXITPIDONE
;
822 set_current_state(TASK_UNINTERRUPTIBLE
);
826 exit_signals(tsk
); /* sets PF_EXITING */
828 * Ensure that all new tsk->pi_lock acquisitions must observe
829 * PF_EXITING. Serializes against futex.c:attach_to_pi_owner().
833 * Ensure that we must observe the pi_state in exit_mm() ->
834 * mm_release() -> exit_pi_state_list().
836 raw_spin_unlock_wait(&tsk
->pi_lock
);
838 if (unlikely(in_atomic())) {
839 pr_info("note: %s[%d] exited with preempt_count %d\n",
840 current
->comm
, task_pid_nr(current
),
842 preempt_count_set(PREEMPT_ENABLED
);
845 /* sync mm's RSS info before statistics gathering */
847 sync_mm_rss(tsk
->mm
);
848 acct_update_integrals(tsk
);
849 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
851 #ifdef CONFIG_POSIX_TIMERS
852 hrtimer_cancel(&tsk
->signal
->real_timer
);
853 exit_itimers(tsk
->signal
);
856 setmax_mm_hiwater_rss(&tsk
->signal
->maxrss
, tsk
->mm
);
858 acct_collect(code
, group_dead
);
863 tsk
->exit_code
= code
;
864 taskstats_exit(tsk
, group_dead
);
870 trace_sched_process_exit(tsk
);
877 disassociate_ctty(1);
878 exit_task_namespaces(tsk
);
883 * Flush inherited counters to the parent - before the parent
884 * gets woken up by child-exit notifications.
886 * because of cgroup mode, must be called before cgroup_exit()
888 perf_event_exit_task(tsk
);
890 sched_autogroup_exit_task(tsk
);
894 * FIXME: do that only when needed, using sched_exit tracepoint
896 flush_ptrace_hw_breakpoint(tsk
);
898 TASKS_RCU(preempt_disable());
899 TASKS_RCU(tasks_rcu_i
= __srcu_read_lock(&tasks_rcu_exit_srcu
));
900 TASKS_RCU(preempt_enable());
901 exit_notify(tsk
, group_dead
);
902 proc_exit_connector(tsk
);
903 mpol_put_task_policy(tsk
);
905 if (unlikely(current
->pi_state_cache
))
906 kfree(current
->pi_state_cache
);
909 * Make sure we are holding no locks:
911 debug_check_no_locks_held();
913 * We can do this unlocked here. The futex code uses this flag
914 * just to verify whether the pi state cleanup has been done
915 * or not. In the worst case it loops once more.
917 tsk
->flags
|= PF_EXITPIDONE
;
920 exit_io_context(tsk
);
922 if (tsk
->splice_pipe
)
923 free_pipe_info(tsk
->splice_pipe
);
925 if (tsk
->task_frag
.page
)
926 put_page(tsk
->task_frag
.page
);
928 validate_creds_for_do_exit(tsk
);
933 __this_cpu_add(dirty_throttle_leaks
, tsk
->nr_dirtied
);
935 TASKS_RCU(__srcu_read_unlock(&tasks_rcu_exit_srcu
, tasks_rcu_i
));
939 EXPORT_SYMBOL_GPL(do_exit
);
941 void complete_and_exit(struct completion
*comp
, long code
)
948 EXPORT_SYMBOL(complete_and_exit
);
950 SYSCALL_DEFINE1(exit
, int, error_code
)
952 do_exit((error_code
&0xff)<<8);
956 * Take down every thread in the group. This is called by fatal signals
957 * as well as by sys_exit_group (below).
960 do_group_exit(int exit_code
)
962 struct signal_struct
*sig
= current
->signal
;
964 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
966 if (signal_group_exit(sig
))
967 exit_code
= sig
->group_exit_code
;
968 else if (!thread_group_empty(current
)) {
969 struct sighand_struct
*const sighand
= current
->sighand
;
971 spin_lock_irq(&sighand
->siglock
);
972 if (signal_group_exit(sig
))
973 /* Another thread got here before we took the lock. */
974 exit_code
= sig
->group_exit_code
;
976 sig
->group_exit_code
= exit_code
;
977 sig
->flags
= SIGNAL_GROUP_EXIT
;
978 zap_other_threads(current
);
980 spin_unlock_irq(&sighand
->siglock
);
988 * this kills every thread in the thread group. Note that any externally
989 * wait4()-ing process will get the correct exit code - even if this
990 * thread is not the thread group leader.
992 SYSCALL_DEFINE1(exit_group
, int, error_code
)
994 do_group_exit((error_code
& 0xff) << 8);
1000 enum pid_type wo_type
;
1004 struct siginfo __user
*wo_info
;
1005 int __user
*wo_stat
;
1006 struct rusage __user
*wo_rusage
;
1008 wait_queue_t child_wait
;
1013 struct pid
*task_pid_type(struct task_struct
*task
, enum pid_type type
)
1015 if (type
!= PIDTYPE_PID
)
1016 task
= task
->group_leader
;
1017 return task
->pids
[type
].pid
;
1020 static int eligible_pid(struct wait_opts
*wo
, struct task_struct
*p
)
1022 return wo
->wo_type
== PIDTYPE_MAX
||
1023 task_pid_type(p
, wo
->wo_type
) == wo
->wo_pid
;
1027 eligible_child(struct wait_opts
*wo
, bool ptrace
, struct task_struct
*p
)
1029 if (!eligible_pid(wo
, p
))
1033 * Wait for all children (clone and not) if __WALL is set or
1034 * if it is traced by us.
1036 if (ptrace
|| (wo
->wo_flags
& __WALL
))
1040 * Otherwise, wait for clone children *only* if __WCLONE is set;
1041 * otherwise, wait for non-clone children *only*.
1043 * Note: a "clone" child here is one that reports to its parent
1044 * using a signal other than SIGCHLD, or a non-leader thread which
1045 * we can only see if it is traced by us.
1047 if ((p
->exit_signal
!= SIGCHLD
) ^ !!(wo
->wo_flags
& __WCLONE
))
1053 static int wait_noreap_copyout(struct wait_opts
*wo
, struct task_struct
*p
,
1054 pid_t pid
, uid_t uid
, int why
, int status
)
1056 struct siginfo __user
*infop
;
1057 int retval
= wo
->wo_rusage
1058 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1061 infop
= wo
->wo_info
;
1064 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1066 retval
= put_user(0, &infop
->si_errno
);
1068 retval
= put_user((short)why
, &infop
->si_code
);
1070 retval
= put_user(pid
, &infop
->si_pid
);
1072 retval
= put_user(uid
, &infop
->si_uid
);
1074 retval
= put_user(status
, &infop
->si_status
);
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
)
1089 int state
, retval
, status
;
1090 pid_t pid
= task_pid_vnr(p
);
1091 uid_t uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1092 struct siginfo __user
*infop
;
1094 if (!likely(wo
->wo_flags
& WEXITED
))
1097 if (unlikely(wo
->wo_flags
& WNOWAIT
)) {
1098 int exit_code
= p
->exit_code
;
1102 read_unlock(&tasklist_lock
);
1103 sched_annotate_sleep();
1105 if ((exit_code
& 0x7f) == 0) {
1107 status
= exit_code
>> 8;
1109 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1110 status
= exit_code
& 0x7f;
1112 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, status
);
1115 * Move the task's state to DEAD/TRACE, only one thread can do this.
1117 state
= (ptrace_reparented(p
) && thread_group_leader(p
)) ?
1118 EXIT_TRACE
: EXIT_DEAD
;
1119 if (cmpxchg(&p
->exit_state
, EXIT_ZOMBIE
, state
) != EXIT_ZOMBIE
)
1122 * We own this thread, nobody else can reap it.
1124 read_unlock(&tasklist_lock
);
1125 sched_annotate_sleep();
1128 * Check thread_group_leader() to exclude the traced sub-threads.
1130 if (state
== EXIT_DEAD
&& thread_group_leader(p
)) {
1131 struct signal_struct
*sig
= p
->signal
;
1132 struct signal_struct
*psig
= current
->signal
;
1133 unsigned long maxrss
;
1134 u64 tgutime
, tgstime
;
1137 * The resource counters for the group leader are in its
1138 * own task_struct. Those for dead threads in the group
1139 * are in its signal_struct, as are those for the child
1140 * processes it has previously reaped. All these
1141 * accumulate in the parent's signal_struct c* fields.
1143 * We don't bother to take a lock here to protect these
1144 * p->signal fields because the whole thread group is dead
1145 * and nobody can change them.
1147 * psig->stats_lock also protects us from our sub-theads
1148 * which can reap other children at the same time. Until
1149 * we change k_getrusage()-like users to rely on this lock
1150 * we have to take ->siglock as well.
1152 * We use thread_group_cputime_adjusted() to get times for
1153 * the thread group, which consolidates times for all threads
1154 * in the group including the group leader.
1156 thread_group_cputime_adjusted(p
, &tgutime
, &tgstime
);
1157 spin_lock_irq(¤t
->sighand
->siglock
);
1158 write_seqlock(&psig
->stats_lock
);
1159 psig
->cutime
+= tgutime
+ sig
->cutime
;
1160 psig
->cstime
+= tgstime
+ sig
->cstime
;
1161 psig
->cgtime
+= task_gtime(p
) + sig
->gtime
+ sig
->cgtime
;
1163 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1165 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1167 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1169 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1171 task_io_get_inblock(p
) +
1172 sig
->inblock
+ sig
->cinblock
;
1174 task_io_get_oublock(p
) +
1175 sig
->oublock
+ sig
->coublock
;
1176 maxrss
= max(sig
->maxrss
, sig
->cmaxrss
);
1177 if (psig
->cmaxrss
< maxrss
)
1178 psig
->cmaxrss
= maxrss
;
1179 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1180 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1181 write_sequnlock(&psig
->stats_lock
);
1182 spin_unlock_irq(¤t
->sighand
->siglock
);
1185 retval
= wo
->wo_rusage
1186 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1187 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1188 ? p
->signal
->group_exit_code
: p
->exit_code
;
1189 if (!retval
&& wo
->wo_stat
)
1190 retval
= put_user(status
, wo
->wo_stat
);
1192 infop
= wo
->wo_info
;
1193 if (!retval
&& infop
)
1194 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1195 if (!retval
&& infop
)
1196 retval
= put_user(0, &infop
->si_errno
);
1197 if (!retval
&& infop
) {
1200 if ((status
& 0x7f) == 0) {
1204 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1207 retval
= put_user((short)why
, &infop
->si_code
);
1209 retval
= put_user(status
, &infop
->si_status
);
1211 if (!retval
&& infop
)
1212 retval
= put_user(pid
, &infop
->si_pid
);
1213 if (!retval
&& infop
)
1214 retval
= put_user(uid
, &infop
->si_uid
);
1218 if (state
== EXIT_TRACE
) {
1219 write_lock_irq(&tasklist_lock
);
1220 /* We dropped tasklist, ptracer could die and untrace */
1223 /* If parent wants a zombie, don't release it now */
1224 state
= EXIT_ZOMBIE
;
1225 if (do_notify_parent(p
, p
->exit_signal
))
1227 p
->exit_state
= state
;
1228 write_unlock_irq(&tasklist_lock
);
1230 if (state
== EXIT_DEAD
)
1236 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1239 if (task_is_traced(p
) && !(p
->jobctl
& JOBCTL_LISTENING
))
1240 return &p
->exit_code
;
1242 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1243 return &p
->signal
->group_exit_code
;
1249 * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
1251 * @ptrace: is the wait for ptrace
1252 * @p: task to wait for
1254 * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
1257 * read_lock(&tasklist_lock), which is released if return value is
1258 * non-zero. Also, grabs and releases @p->sighand->siglock.
1261 * 0 if wait condition didn't exist and search for other wait conditions
1262 * should continue. Non-zero return, -errno on failure and @p's pid on
1263 * success, implies that tasklist_lock is released and wait condition
1264 * search should terminate.
1266 static int wait_task_stopped(struct wait_opts
*wo
,
1267 int ptrace
, struct task_struct
*p
)
1269 struct siginfo __user
*infop
;
1270 int retval
, exit_code
, *p_code
, why
;
1271 uid_t uid
= 0; /* unneeded, required by compiler */
1275 * Traditionally we see ptrace'd stopped tasks regardless of options.
1277 if (!ptrace
&& !(wo
->wo_flags
& WUNTRACED
))
1280 if (!task_stopped_code(p
, ptrace
))
1284 spin_lock_irq(&p
->sighand
->siglock
);
1286 p_code
= task_stopped_code(p
, ptrace
);
1287 if (unlikely(!p_code
))
1290 exit_code
= *p_code
;
1294 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1297 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1299 spin_unlock_irq(&p
->sighand
->siglock
);
1304 * Now we are pretty sure this task is interesting.
1305 * Make sure it doesn't get reaped out from under us while we
1306 * give up the lock and then examine it below. We don't want to
1307 * keep holding onto the tasklist_lock while we call getrusage and
1308 * possibly take page faults for user memory.
1311 pid
= task_pid_vnr(p
);
1312 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1313 read_unlock(&tasklist_lock
);
1314 sched_annotate_sleep();
1316 if (unlikely(wo
->wo_flags
& WNOWAIT
))
1317 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, exit_code
);
1319 retval
= wo
->wo_rusage
1320 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1321 if (!retval
&& wo
->wo_stat
)
1322 retval
= put_user((exit_code
<< 8) | 0x7f, wo
->wo_stat
);
1324 infop
= wo
->wo_info
;
1325 if (!retval
&& infop
)
1326 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1327 if (!retval
&& infop
)
1328 retval
= put_user(0, &infop
->si_errno
);
1329 if (!retval
&& infop
)
1330 retval
= put_user((short)why
, &infop
->si_code
);
1331 if (!retval
&& infop
)
1332 retval
= put_user(exit_code
, &infop
->si_status
);
1333 if (!retval
&& infop
)
1334 retval
= put_user(pid
, &infop
->si_pid
);
1335 if (!retval
&& infop
)
1336 retval
= put_user(uid
, &infop
->si_uid
);
1346 * Handle do_wait work for one task in a live, non-stopped state.
1347 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1348 * the lock and this task is uninteresting. If we return nonzero, we have
1349 * released the lock and the system call should return.
1351 static int wait_task_continued(struct wait_opts
*wo
, struct task_struct
*p
)
1357 if (!unlikely(wo
->wo_flags
& WCONTINUED
))
1360 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1363 spin_lock_irq(&p
->sighand
->siglock
);
1364 /* Re-check with the lock held. */
1365 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1366 spin_unlock_irq(&p
->sighand
->siglock
);
1369 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1370 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1371 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1372 spin_unlock_irq(&p
->sighand
->siglock
);
1374 pid
= task_pid_vnr(p
);
1376 read_unlock(&tasklist_lock
);
1377 sched_annotate_sleep();
1380 retval
= wo
->wo_rusage
1381 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1383 if (!retval
&& wo
->wo_stat
)
1384 retval
= put_user(0xffff, wo
->wo_stat
);
1388 retval
= wait_noreap_copyout(wo
, p
, pid
, uid
,
1389 CLD_CONTINUED
, SIGCONT
);
1390 BUG_ON(retval
== 0);
1397 * Consider @p for a wait by @parent.
1399 * -ECHILD should be in ->notask_error before the first call.
1400 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1401 * Returns zero if the search for a child should continue;
1402 * then ->notask_error is 0 if @p is an eligible child,
1405 static int wait_consider_task(struct wait_opts
*wo
, int ptrace
,
1406 struct task_struct
*p
)
1409 * We can race with wait_task_zombie() from another thread.
1410 * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
1411 * can't confuse the checks below.
1413 int exit_state
= ACCESS_ONCE(p
->exit_state
);
1416 if (unlikely(exit_state
== EXIT_DEAD
))
1419 ret
= eligible_child(wo
, ptrace
, p
);
1423 if (unlikely(exit_state
== EXIT_TRACE
)) {
1425 * ptrace == 0 means we are the natural parent. In this case
1426 * we should clear notask_error, debugger will notify us.
1428 if (likely(!ptrace
))
1429 wo
->notask_error
= 0;
1433 if (likely(!ptrace
) && unlikely(p
->ptrace
)) {
1435 * If it is traced by its real parent's group, just pretend
1436 * the caller is ptrace_do_wait() and reap this child if it
1439 * This also hides group stop state from real parent; otherwise
1440 * a single stop can be reported twice as group and ptrace stop.
1441 * If a ptracer wants to distinguish these two events for its
1442 * own children it should create a separate process which takes
1443 * the role of real parent.
1445 if (!ptrace_reparented(p
))
1450 if (exit_state
== EXIT_ZOMBIE
) {
1451 /* we don't reap group leaders with subthreads */
1452 if (!delay_group_leader(p
)) {
1454 * A zombie ptracee is only visible to its ptracer.
1455 * Notification and reaping will be cascaded to the
1456 * real parent when the ptracer detaches.
1458 if (unlikely(ptrace
) || likely(!p
->ptrace
))
1459 return wait_task_zombie(wo
, p
);
1463 * Allow access to stopped/continued state via zombie by
1464 * falling through. Clearing of notask_error is complex.
1468 * If WEXITED is set, notask_error should naturally be
1469 * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
1470 * so, if there are live subthreads, there are events to
1471 * wait for. If all subthreads are dead, it's still safe
1472 * to clear - this function will be called again in finite
1473 * amount time once all the subthreads are released and
1474 * will then return without clearing.
1478 * Stopped state is per-task and thus can't change once the
1479 * target task dies. Only continued and exited can happen.
1480 * Clear notask_error if WCONTINUED | WEXITED.
1482 if (likely(!ptrace
) || (wo
->wo_flags
& (WCONTINUED
| WEXITED
)))
1483 wo
->notask_error
= 0;
1486 * @p is alive and it's gonna stop, continue or exit, so
1487 * there always is something to wait for.
1489 wo
->notask_error
= 0;
1493 * Wait for stopped. Depending on @ptrace, different stopped state
1494 * is used and the two don't interact with each other.
1496 ret
= wait_task_stopped(wo
, ptrace
, p
);
1501 * Wait for continued. There's only one continued state and the
1502 * ptracer can consume it which can confuse the real parent. Don't
1503 * use WCONTINUED from ptracer. You don't need or want it.
1505 return wait_task_continued(wo
, p
);
1509 * Do the work of do_wait() for one thread in the group, @tsk.
1511 * -ECHILD should be in ->notask_error before the first call.
1512 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1513 * Returns zero if the search for a child should continue; then
1514 * ->notask_error is 0 if there were any eligible children,
1517 static int do_wait_thread(struct wait_opts
*wo
, struct task_struct
*tsk
)
1519 struct task_struct
*p
;
1521 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1522 int ret
= wait_consider_task(wo
, 0, p
);
1531 static int ptrace_do_wait(struct wait_opts
*wo
, struct task_struct
*tsk
)
1533 struct task_struct
*p
;
1535 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1536 int ret
= wait_consider_task(wo
, 1, p
);
1545 static int child_wait_callback(wait_queue_t
*wait
, unsigned mode
,
1546 int sync
, void *key
)
1548 struct wait_opts
*wo
= container_of(wait
, struct wait_opts
,
1550 struct task_struct
*p
= key
;
1552 if (!eligible_pid(wo
, p
))
1555 if ((wo
->wo_flags
& __WNOTHREAD
) && wait
->private != p
->parent
)
1558 return default_wake_function(wait
, mode
, sync
, key
);
1561 void __wake_up_parent(struct task_struct
*p
, struct task_struct
*parent
)
1563 __wake_up_sync_key(&parent
->signal
->wait_chldexit
,
1564 TASK_INTERRUPTIBLE
, 1, p
);
1567 static long do_wait(struct wait_opts
*wo
)
1569 struct task_struct
*tsk
;
1572 trace_sched_process_wait(wo
->wo_pid
);
1574 init_waitqueue_func_entry(&wo
->child_wait
, child_wait_callback
);
1575 wo
->child_wait
.private = current
;
1576 add_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1579 * If there is nothing that can match our criteria, just get out.
1580 * We will clear ->notask_error to zero if we see any child that
1581 * might later match our criteria, even if we are not able to reap
1584 wo
->notask_error
= -ECHILD
;
1585 if ((wo
->wo_type
< PIDTYPE_MAX
) &&
1586 (!wo
->wo_pid
|| hlist_empty(&wo
->wo_pid
->tasks
[wo
->wo_type
])))
1589 set_current_state(TASK_INTERRUPTIBLE
);
1590 read_lock(&tasklist_lock
);
1593 retval
= do_wait_thread(wo
, tsk
);
1597 retval
= ptrace_do_wait(wo
, tsk
);
1601 if (wo
->wo_flags
& __WNOTHREAD
)
1603 } while_each_thread(current
, tsk
);
1604 read_unlock(&tasklist_lock
);
1607 retval
= wo
->notask_error
;
1608 if (!retval
&& !(wo
->wo_flags
& WNOHANG
)) {
1609 retval
= -ERESTARTSYS
;
1610 if (!signal_pending(current
)) {
1616 __set_current_state(TASK_RUNNING
);
1617 remove_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1621 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1622 infop
, int, options
, struct rusage __user
*, ru
)
1624 struct wait_opts wo
;
1625 struct pid
*pid
= NULL
;
1629 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
|
1630 __WNOTHREAD
|__WCLONE
|__WALL
))
1632 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1645 type
= PIDTYPE_PGID
;
1653 if (type
< PIDTYPE_MAX
)
1654 pid
= find_get_pid(upid
);
1658 wo
.wo_flags
= options
;
1668 * For a WNOHANG return, clear out all the fields
1669 * we would set so the user can easily tell the
1673 ret
= put_user(0, &infop
->si_signo
);
1675 ret
= put_user(0, &infop
->si_errno
);
1677 ret
= put_user(0, &infop
->si_code
);
1679 ret
= put_user(0, &infop
->si_pid
);
1681 ret
= put_user(0, &infop
->si_uid
);
1683 ret
= put_user(0, &infop
->si_status
);
1690 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1691 int, options
, struct rusage __user
*, ru
)
1693 struct wait_opts wo
;
1694 struct pid
*pid
= NULL
;
1698 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1699 __WNOTHREAD
|__WCLONE
|__WALL
))
1704 else if (upid
< 0) {
1705 type
= PIDTYPE_PGID
;
1706 pid
= find_get_pid(-upid
);
1707 } else if (upid
== 0) {
1708 type
= PIDTYPE_PGID
;
1709 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1710 } else /* upid > 0 */ {
1712 pid
= find_get_pid(upid
);
1717 wo
.wo_flags
= options
| WEXITED
;
1719 wo
.wo_stat
= stat_addr
;
1727 #ifdef __ARCH_WANT_SYS_WAITPID
1730 * sys_waitpid() remains for compatibility. waitpid() should be
1731 * implemented by calling sys_wait4() from libc.a.
1733 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1735 return sys_wait4(pid
, stat_addr
, options
, NULL
);