3602f468e3a0c277030dfdaf95c6665ea77df47a
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 #include <linux/slab.h>
9 #include <linux/interrupt.h>
10 #include <linux/module.h>
11 #include <linux/capability.h>
12 #include <linux/completion.h>
13 #include <linux/personality.h>
14 #include <linux/tty.h>
15 #include <linux/iocontext.h>
16 #include <linux/key.h>
17 #include <linux/security.h>
18 #include <linux/cpu.h>
19 #include <linux/acct.h>
20 #include <linux/tsacct_kern.h>
21 #include <linux/file.h>
22 #include <linux/fdtable.h>
23 #include <linux/binfmts.h>
24 #include <linux/nsproxy.h>
25 #include <linux/pid_namespace.h>
26 #include <linux/ptrace.h>
27 #include <linux/profile.h>
28 #include <linux/mount.h>
29 #include <linux/proc_fs.h>
30 #include <linux/kthread.h>
31 #include <linux/mempolicy.h>
32 #include <linux/taskstats_kern.h>
33 #include <linux/delayacct.h>
34 #include <linux/freezer.h>
35 #include <linux/cgroup.h>
36 #include <linux/syscalls.h>
37 #include <linux/signal.h>
38 #include <linux/posix-timers.h>
39 #include <linux/cn_proc.h>
40 #include <linux/mutex.h>
41 #include <linux/futex.h>
42 #include <linux/pipe_fs_i.h>
43 #include <linux/audit.h> /* for audit_free() */
44 #include <linux/resource.h>
45 #include <linux/blkdev.h>
46 #include <linux/task_io_accounting_ops.h>
47 #include <linux/tracehook.h>
48 #include <linux/fs_struct.h>
49 #include <linux/init_task.h>
50 #include <linux/perf_event.h>
51 #include <trace/events/sched.h>
52 #include <linux/hw_breakpoint.h>
54 #include <asm/uaccess.h>
55 #include <asm/unistd.h>
56 #include <asm/pgtable.h>
57 #include <asm/mmu_context.h>
59 static void exit_mm(struct task_struct
* tsk
);
61 static void __unhash_process(struct task_struct
*p
, bool group_dead
)
64 detach_pid(p
, PIDTYPE_PID
);
66 detach_pid(p
, PIDTYPE_PGID
);
67 detach_pid(p
, PIDTYPE_SID
);
69 list_del_rcu(&p
->tasks
);
70 list_del_init(&p
->sibling
);
71 __get_cpu_var(process_counts
)--;
73 list_del_rcu(&p
->thread_group
);
77 * This function expects the tasklist_lock write-locked.
79 static void __exit_signal(struct task_struct
*tsk
)
81 struct signal_struct
*sig
= tsk
->signal
;
82 bool group_dead
= thread_group_leader(tsk
);
83 struct sighand_struct
*sighand
;
84 struct tty_struct
*uninitialized_var(tty
);
87 BUG_ON(!atomic_read(&sig
->count
));
89 sighand
= rcu_dereference_check(tsk
->sighand
,
90 rcu_read_lock_held() ||
91 lockdep_tasklist_lock_is_held());
92 spin_lock(&sighand
->siglock
);
93 atomic_dec(&sig
->count
);
95 posix_cpu_timers_exit(tsk
);
97 posix_cpu_timers_exit_group(tsk
);
102 * If there is any task waiting for the group exit
105 if (sig
->notify_count
> 0 && !--sig
->notify_count
)
106 wake_up_process(sig
->group_exit_task
);
108 if (tsk
== sig
->curr_target
)
109 sig
->curr_target
= next_thread(tsk
);
111 * Accumulate here the counters for all threads but the
112 * group leader as they die, so they can be added into
113 * the process-wide totals when those are taken.
114 * The group leader stays around as a zombie as long
115 * as there are other threads. When it gets reaped,
116 * the exit.c code will add its counts into these totals.
117 * We won't ever get here for the group leader, since it
118 * will have been the last reference on the signal_struct.
120 sig
->utime
= cputime_add(sig
->utime
, tsk
->utime
);
121 sig
->stime
= cputime_add(sig
->stime
, tsk
->stime
);
122 sig
->gtime
= cputime_add(sig
->gtime
, tsk
->gtime
);
123 sig
->min_flt
+= tsk
->min_flt
;
124 sig
->maj_flt
+= tsk
->maj_flt
;
125 sig
->nvcsw
+= tsk
->nvcsw
;
126 sig
->nivcsw
+= tsk
->nivcsw
;
127 sig
->inblock
+= task_io_get_inblock(tsk
);
128 sig
->oublock
+= task_io_get_oublock(tsk
);
129 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
130 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
133 __unhash_process(tsk
, group_dead
);
136 * Do this under ->siglock, we can race with another thread
137 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
139 flush_sigqueue(&tsk
->pending
);
141 spin_unlock(&sighand
->siglock
);
143 __cleanup_sighand(sighand
);
144 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
146 flush_sigqueue(&sig
->shared_pending
);
147 taskstats_tgid_free(sig
);
152 static void delayed_put_task_struct(struct rcu_head
*rhp
)
154 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
156 #ifdef CONFIG_PERF_EVENTS
157 WARN_ON_ONCE(tsk
->perf_event_ctxp
);
159 trace_sched_process_free(tsk
);
160 put_task_struct(tsk
);
164 void release_task(struct task_struct
* p
)
166 struct task_struct
*leader
;
169 tracehook_prepare_release_task(p
);
170 /* don't need to get the RCU readlock here - the process is dead and
171 * can't be modifying its own credentials. But shut RCU-lockdep up */
173 atomic_dec(&__task_cred(p
)->user
->processes
);
178 write_lock_irq(&tasklist_lock
);
179 tracehook_finish_release_task(p
);
183 * If we are the last non-leader member of the thread
184 * group, and the leader is zombie, then notify the
185 * group leader's parent process. (if it wants notification.)
188 leader
= p
->group_leader
;
189 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
190 BUG_ON(task_detached(leader
));
191 do_notify_parent(leader
, leader
->exit_signal
);
193 * If we were the last child thread and the leader has
194 * exited already, and the leader's parent ignores SIGCHLD,
195 * then we are the one who should release the leader.
197 * do_notify_parent() will have marked it self-reaping in
200 zap_leader
= task_detached(leader
);
203 * This maintains the invariant that release_task()
204 * only runs on a task in EXIT_DEAD, just for sanity.
207 leader
->exit_state
= EXIT_DEAD
;
210 write_unlock_irq(&tasklist_lock
);
212 call_rcu(&p
->rcu
, delayed_put_task_struct
);
215 if (unlikely(zap_leader
))
220 * This checks not only the pgrp, but falls back on the pid if no
221 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
224 * The caller must hold rcu lock or the tasklist lock.
226 struct pid
*session_of_pgrp(struct pid
*pgrp
)
228 struct task_struct
*p
;
229 struct pid
*sid
= NULL
;
231 p
= pid_task(pgrp
, PIDTYPE_PGID
);
233 p
= pid_task(pgrp
, PIDTYPE_PID
);
235 sid
= task_session(p
);
241 * Determine if a process group is "orphaned", according to the POSIX
242 * definition in 2.2.2.52. Orphaned process groups are not to be affected
243 * by terminal-generated stop signals. Newly orphaned process groups are
244 * to receive a SIGHUP and a SIGCONT.
246 * "I ask you, have you ever known what it is to be an orphan?"
248 static int will_become_orphaned_pgrp(struct pid
*pgrp
, struct task_struct
*ignored_task
)
250 struct task_struct
*p
;
252 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
253 if ((p
== ignored_task
) ||
254 (p
->exit_state
&& thread_group_empty(p
)) ||
255 is_global_init(p
->real_parent
))
258 if (task_pgrp(p
->real_parent
) != pgrp
&&
259 task_session(p
->real_parent
) == task_session(p
))
261 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
266 int is_current_pgrp_orphaned(void)
270 read_lock(&tasklist_lock
);
271 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
272 read_unlock(&tasklist_lock
);
277 static int has_stopped_jobs(struct pid
*pgrp
)
280 struct task_struct
*p
;
282 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
283 if (!task_is_stopped(p
))
287 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
292 * Check to see if any process groups have become orphaned as
293 * a result of our exiting, and if they have any stopped jobs,
294 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
297 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
299 struct pid
*pgrp
= task_pgrp(tsk
);
300 struct task_struct
*ignored_task
= tsk
;
303 /* exit: our father is in a different pgrp than
304 * we are and we were the only connection outside.
306 parent
= tsk
->real_parent
;
308 /* reparent: our child is in a different pgrp than
309 * we are, and it was the only connection outside.
313 if (task_pgrp(parent
) != pgrp
&&
314 task_session(parent
) == task_session(tsk
) &&
315 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
316 has_stopped_jobs(pgrp
)) {
317 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
318 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
323 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
325 * If a kernel thread is launched as a result of a system call, or if
326 * it ever exits, it should generally reparent itself to kthreadd so it
327 * isn't in the way of other processes and is correctly cleaned up on exit.
329 * The various task state such as scheduling policy and priority may have
330 * been inherited from a user process, so we reset them to sane values here.
332 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
334 static void reparent_to_kthreadd(void)
336 write_lock_irq(&tasklist_lock
);
338 ptrace_unlink(current
);
339 /* Reparent to init */
340 current
->real_parent
= current
->parent
= kthreadd_task
;
341 list_move_tail(¤t
->sibling
, ¤t
->real_parent
->children
);
343 /* Set the exit signal to SIGCHLD so we signal init on exit */
344 current
->exit_signal
= SIGCHLD
;
346 if (task_nice(current
) < 0)
347 set_user_nice(current
, 0);
351 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
352 sizeof(current
->signal
->rlim
));
354 atomic_inc(&init_cred
.usage
);
355 commit_creds(&init_cred
);
356 write_unlock_irq(&tasklist_lock
);
359 void __set_special_pids(struct pid
*pid
)
361 struct task_struct
*curr
= current
->group_leader
;
363 if (task_session(curr
) != pid
)
364 change_pid(curr
, PIDTYPE_SID
, pid
);
366 if (task_pgrp(curr
) != pid
)
367 change_pid(curr
, PIDTYPE_PGID
, pid
);
370 static void set_special_pids(struct pid
*pid
)
372 write_lock_irq(&tasklist_lock
);
373 __set_special_pids(pid
);
374 write_unlock_irq(&tasklist_lock
);
378 * Let kernel threads use this to say that they allow a certain signal.
379 * Must not be used if kthread was cloned with CLONE_SIGHAND.
381 int allow_signal(int sig
)
383 if (!valid_signal(sig
) || sig
< 1)
386 spin_lock_irq(¤t
->sighand
->siglock
);
387 /* This is only needed for daemonize()'ed kthreads */
388 sigdelset(¤t
->blocked
, sig
);
390 * Kernel threads handle their own signals. Let the signal code
391 * know it'll be handled, so that they don't get converted to
392 * SIGKILL or just silently dropped.
394 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
396 spin_unlock_irq(¤t
->sighand
->siglock
);
400 EXPORT_SYMBOL(allow_signal
);
402 int disallow_signal(int sig
)
404 if (!valid_signal(sig
) || sig
< 1)
407 spin_lock_irq(¤t
->sighand
->siglock
);
408 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= SIG_IGN
;
410 spin_unlock_irq(¤t
->sighand
->siglock
);
414 EXPORT_SYMBOL(disallow_signal
);
417 * Put all the gunge required to become a kernel thread without
418 * attached user resources in one place where it belongs.
421 void daemonize(const char *name
, ...)
426 va_start(args
, name
);
427 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
431 * If we were started as result of loading a module, close all of the
432 * user space pages. We don't need them, and if we didn't close them
433 * they would be locked into memory.
437 * We don't want to have TIF_FREEZE set if the system-wide hibernation
438 * or suspend transition begins right now.
440 current
->flags
|= (PF_NOFREEZE
| PF_KTHREAD
);
442 if (current
->nsproxy
!= &init_nsproxy
) {
443 get_nsproxy(&init_nsproxy
);
444 switch_task_namespaces(current
, &init_nsproxy
);
446 set_special_pids(&init_struct_pid
);
447 proc_clear_tty(current
);
449 /* Block and flush all signals */
450 sigfillset(&blocked
);
451 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
452 flush_signals(current
);
454 /* Become as one with the init task */
456 daemonize_fs_struct();
458 current
->files
= init_task
.files
;
459 atomic_inc(¤t
->files
->count
);
461 reparent_to_kthreadd();
464 EXPORT_SYMBOL(daemonize
);
466 static void close_files(struct files_struct
* files
)
474 * It is safe to dereference the fd table without RCU or
475 * ->file_lock because this is the last reference to the
476 * files structure. But use RCU to shut RCU-lockdep up.
479 fdt
= files_fdtable(files
);
484 if (i
>= fdt
->max_fds
)
486 set
= fdt
->open_fds
->fds_bits
[j
++];
489 struct file
* file
= xchg(&fdt
->fd
[i
], NULL
);
491 filp_close(file
, files
);
501 struct files_struct
*get_files_struct(struct task_struct
*task
)
503 struct files_struct
*files
;
508 atomic_inc(&files
->count
);
514 void put_files_struct(struct files_struct
*files
)
518 if (atomic_dec_and_test(&files
->count
)) {
521 * Free the fd and fdset arrays if we expanded them.
522 * If the fdtable was embedded, pass files for freeing
523 * at the end of the RCU grace period. Otherwise,
524 * you can free files immediately.
527 fdt
= files_fdtable(files
);
528 if (fdt
!= &files
->fdtab
)
529 kmem_cache_free(files_cachep
, files
);
535 void reset_files_struct(struct files_struct
*files
)
537 struct task_struct
*tsk
= current
;
538 struct files_struct
*old
;
544 put_files_struct(old
);
547 void exit_files(struct task_struct
*tsk
)
549 struct files_struct
* files
= tsk
->files
;
555 put_files_struct(files
);
559 #ifdef CONFIG_MM_OWNER
561 * Task p is exiting and it owned mm, lets find a new owner for it
564 mm_need_new_owner(struct mm_struct
*mm
, struct task_struct
*p
)
567 * If there are other users of the mm and the owner (us) is exiting
568 * we need to find a new owner to take on the responsibility.
570 if (atomic_read(&mm
->mm_users
) <= 1)
577 void mm_update_next_owner(struct mm_struct
*mm
)
579 struct task_struct
*c
, *g
, *p
= current
;
582 if (!mm_need_new_owner(mm
, p
))
585 read_lock(&tasklist_lock
);
587 * Search in the children
589 list_for_each_entry(c
, &p
->children
, sibling
) {
591 goto assign_new_owner
;
595 * Search in the siblings
597 list_for_each_entry(c
, &p
->real_parent
->children
, sibling
) {
599 goto assign_new_owner
;
603 * Search through everything else. We should not get
606 do_each_thread(g
, c
) {
608 goto assign_new_owner
;
609 } while_each_thread(g
, c
);
611 read_unlock(&tasklist_lock
);
613 * We found no owner yet mm_users > 1: this implies that we are
614 * most likely racing with swapoff (try_to_unuse()) or /proc or
615 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
624 * The task_lock protects c->mm from changing.
625 * We always want mm->owner->mm == mm
629 * Delay read_unlock() till we have the task_lock()
630 * to ensure that c does not slip away underneath us
632 read_unlock(&tasklist_lock
);
642 #endif /* CONFIG_MM_OWNER */
645 * Turn us into a lazy TLB process if we
648 static void exit_mm(struct task_struct
* tsk
)
650 struct mm_struct
*mm
= tsk
->mm
;
651 struct core_state
*core_state
;
657 * Serialize with any possible pending coredump.
658 * We must hold mmap_sem around checking core_state
659 * and clearing tsk->mm. The core-inducing thread
660 * will increment ->nr_threads for each thread in the
661 * group with ->mm != NULL.
663 down_read(&mm
->mmap_sem
);
664 core_state
= mm
->core_state
;
666 struct core_thread self
;
667 up_read(&mm
->mmap_sem
);
670 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
672 * Implies mb(), the result of xchg() must be visible
673 * to core_state->dumper.
675 if (atomic_dec_and_test(&core_state
->nr_threads
))
676 complete(&core_state
->startup
);
679 set_task_state(tsk
, TASK_UNINTERRUPTIBLE
);
680 if (!self
.task
) /* see coredump_finish() */
684 __set_task_state(tsk
, TASK_RUNNING
);
685 down_read(&mm
->mmap_sem
);
687 atomic_inc(&mm
->mm_count
);
688 BUG_ON(mm
!= tsk
->active_mm
);
689 /* more a memory barrier than a real lock */
692 up_read(&mm
->mmap_sem
);
693 enter_lazy_tlb(mm
, current
);
694 /* We don't want this task to be frozen prematurely */
695 clear_freeze_flag(tsk
);
697 mm_update_next_owner(mm
);
702 * When we die, we re-parent all our children.
703 * Try to give them to another thread in our thread
704 * group, and if no such member exists, give it to
705 * the child reaper process (ie "init") in our pid
708 static struct task_struct
*find_new_reaper(struct task_struct
*father
)
710 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
711 struct task_struct
*thread
;
714 while_each_thread(father
, thread
) {
715 if (thread
->flags
& PF_EXITING
)
717 if (unlikely(pid_ns
->child_reaper
== father
))
718 pid_ns
->child_reaper
= thread
;
722 if (unlikely(pid_ns
->child_reaper
== father
)) {
723 write_unlock_irq(&tasklist_lock
);
724 if (unlikely(pid_ns
== &init_pid_ns
))
725 panic("Attempted to kill init!");
727 zap_pid_ns_processes(pid_ns
);
728 write_lock_irq(&tasklist_lock
);
730 * We can not clear ->child_reaper or leave it alone.
731 * There may by stealth EXIT_DEAD tasks on ->children,
732 * forget_original_parent() must move them somewhere.
734 pid_ns
->child_reaper
= init_pid_ns
.child_reaper
;
737 return pid_ns
->child_reaper
;
741 * Any that need to be release_task'd are put on the @dead list.
743 static void reparent_leader(struct task_struct
*father
, struct task_struct
*p
,
744 struct list_head
*dead
)
746 list_move_tail(&p
->sibling
, &p
->real_parent
->children
);
748 if (task_detached(p
))
751 * If this is a threaded reparent there is no need to
752 * notify anyone anything has happened.
754 if (same_thread_group(p
->real_parent
, father
))
757 /* We don't want people slaying init. */
758 p
->exit_signal
= SIGCHLD
;
760 /* If it has exited notify the new parent about this child's death. */
761 if (!task_ptrace(p
) &&
762 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
763 do_notify_parent(p
, p
->exit_signal
);
764 if (task_detached(p
)) {
765 p
->exit_state
= EXIT_DEAD
;
766 list_move_tail(&p
->sibling
, dead
);
770 kill_orphaned_pgrp(p
, father
);
773 static void forget_original_parent(struct task_struct
*father
)
775 struct task_struct
*p
, *n
, *reaper
;
776 LIST_HEAD(dead_children
);
780 write_lock_irq(&tasklist_lock
);
781 reaper
= find_new_reaper(father
);
783 list_for_each_entry_safe(p
, n
, &father
->children
, sibling
) {
784 struct task_struct
*t
= p
;
786 t
->real_parent
= reaper
;
787 if (t
->parent
== father
) {
788 BUG_ON(task_ptrace(t
));
789 t
->parent
= t
->real_parent
;
791 if (t
->pdeath_signal
)
792 group_send_sig_info(t
->pdeath_signal
,
794 } while_each_thread(p
, t
);
795 reparent_leader(father
, p
, &dead_children
);
797 write_unlock_irq(&tasklist_lock
);
799 BUG_ON(!list_empty(&father
->children
));
801 list_for_each_entry_safe(p
, n
, &dead_children
, sibling
) {
802 list_del_init(&p
->sibling
);
808 * Send signals to all our closest relatives so that they know
809 * to properly mourn us..
811 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
817 * This does two things:
819 * A. Make init inherit all the child processes
820 * B. Check to see if any process groups have become orphaned
821 * as a result of our exiting, and if they have any stopped
822 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
824 forget_original_parent(tsk
);
825 exit_task_namespaces(tsk
);
827 write_lock_irq(&tasklist_lock
);
829 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
831 /* Let father know we died
833 * Thread signals are configurable, but you aren't going to use
834 * that to send signals to arbitary processes.
835 * That stops right now.
837 * If the parent exec id doesn't match the exec id we saved
838 * when we started then we know the parent has changed security
841 * If our self_exec id doesn't match our parent_exec_id then
842 * we have changed execution domain as these two values started
843 * the same after a fork.
845 if (tsk
->exit_signal
!= SIGCHLD
&& !task_detached(tsk
) &&
846 (tsk
->parent_exec_id
!= tsk
->real_parent
->self_exec_id
||
847 tsk
->self_exec_id
!= tsk
->parent_exec_id
))
848 tsk
->exit_signal
= SIGCHLD
;
850 signal
= tracehook_notify_death(tsk
, &cookie
, group_dead
);
852 signal
= do_notify_parent(tsk
, signal
);
854 tsk
->exit_state
= signal
== DEATH_REAP
? EXIT_DEAD
: EXIT_ZOMBIE
;
856 /* mt-exec, de_thread() is waiting for group leader */
857 if (unlikely(tsk
->signal
->notify_count
< 0))
858 wake_up_process(tsk
->signal
->group_exit_task
);
859 write_unlock_irq(&tasklist_lock
);
861 tracehook_report_death(tsk
, signal
, cookie
, group_dead
);
863 /* If the process is dead, release it - nobody will wait for it */
864 if (signal
== DEATH_REAP
)
868 #ifdef CONFIG_DEBUG_STACK_USAGE
869 static void check_stack_usage(void)
871 static DEFINE_SPINLOCK(low_water_lock
);
872 static int lowest_to_date
= THREAD_SIZE
;
875 free
= stack_not_used(current
);
877 if (free
>= lowest_to_date
)
880 spin_lock(&low_water_lock
);
881 if (free
< lowest_to_date
) {
882 printk(KERN_WARNING
"%s used greatest stack depth: %lu bytes "
884 current
->comm
, free
);
885 lowest_to_date
= free
;
887 spin_unlock(&low_water_lock
);
890 static inline void check_stack_usage(void) {}
893 NORET_TYPE
void do_exit(long code
)
895 struct task_struct
*tsk
= current
;
898 profile_task_exit(tsk
);
900 WARN_ON(atomic_read(&tsk
->fs_excl
));
902 if (unlikely(in_interrupt()))
903 panic("Aiee, killing interrupt handler!");
904 if (unlikely(!tsk
->pid
))
905 panic("Attempted to kill the idle task!");
907 tracehook_report_exit(&code
);
909 validate_creds_for_do_exit(tsk
);
912 * We're taking recursive faults here in do_exit. Safest is to just
913 * leave this task alone and wait for reboot.
915 if (unlikely(tsk
->flags
& PF_EXITING
)) {
917 "Fixing recursive fault but reboot is needed!\n");
919 * We can do this unlocked here. The futex code uses
920 * this flag just to verify whether the pi state
921 * cleanup has been done or not. In the worst case it
922 * loops once more. We pretend that the cleanup was
923 * done as there is no way to return. Either the
924 * OWNER_DIED bit is set by now or we push the blocked
925 * task into the wait for ever nirwana as well.
927 tsk
->flags
|= PF_EXITPIDONE
;
928 set_current_state(TASK_UNINTERRUPTIBLE
);
934 exit_signals(tsk
); /* sets PF_EXITING */
936 * tsk->flags are checked in the futex code to protect against
937 * an exiting task cleaning up the robust pi futexes.
940 raw_spin_unlock_wait(&tsk
->pi_lock
);
942 if (unlikely(in_atomic()))
943 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
944 current
->comm
, task_pid_nr(current
),
947 acct_update_integrals(tsk
);
948 /* sync mm's RSS info before statistics gathering */
950 sync_mm_rss(tsk
, tsk
->mm
);
951 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
953 hrtimer_cancel(&tsk
->signal
->real_timer
);
954 exit_itimers(tsk
->signal
);
956 setmax_mm_hiwater_rss(&tsk
->signal
->maxrss
, tsk
->mm
);
958 acct_collect(code
, group_dead
);
961 if (unlikely(tsk
->audit_context
))
964 tsk
->exit_code
= code
;
965 taskstats_exit(tsk
, group_dead
);
971 trace_sched_process_exit(tsk
);
981 disassociate_ctty(1);
983 module_put(task_thread_info(tsk
)->exec_domain
->module
);
985 proc_exit_connector(tsk
);
988 * FIXME: do that only when needed, using sched_exit tracepoint
990 flush_ptrace_hw_breakpoint(tsk
);
992 * Flush inherited counters to the parent - before the parent
993 * gets woken up by child-exit notifications.
995 perf_event_exit_task(tsk
);
997 exit_notify(tsk
, group_dead
);
1000 mpol_put(tsk
->mempolicy
);
1001 tsk
->mempolicy
= NULL
;
1005 if (unlikely(current
->pi_state_cache
))
1006 kfree(current
->pi_state_cache
);
1009 * Make sure we are holding no locks:
1011 debug_check_no_locks_held(tsk
);
1013 * We can do this unlocked here. The futex code uses this flag
1014 * just to verify whether the pi state cleanup has been done
1015 * or not. In the worst case it loops once more.
1017 tsk
->flags
|= PF_EXITPIDONE
;
1019 if (tsk
->io_context
)
1020 exit_io_context(tsk
);
1022 if (tsk
->splice_pipe
)
1023 __free_pipe_info(tsk
->splice_pipe
);
1025 validate_creds_for_do_exit(tsk
);
1029 /* causes final put_task_struct in finish_task_switch(). */
1030 tsk
->state
= TASK_DEAD
;
1033 /* Avoid "noreturn function does return". */
1035 cpu_relax(); /* For when BUG is null */
1038 EXPORT_SYMBOL_GPL(do_exit
);
1040 NORET_TYPE
void complete_and_exit(struct completion
*comp
, long code
)
1048 EXPORT_SYMBOL(complete_and_exit
);
1050 SYSCALL_DEFINE1(exit
, int, error_code
)
1052 do_exit((error_code
&0xff)<<8);
1056 * Take down every thread in the group. This is called by fatal signals
1057 * as well as by sys_exit_group (below).
1060 do_group_exit(int exit_code
)
1062 struct signal_struct
*sig
= current
->signal
;
1064 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
1066 if (signal_group_exit(sig
))
1067 exit_code
= sig
->group_exit_code
;
1068 else if (!thread_group_empty(current
)) {
1069 struct sighand_struct
*const sighand
= current
->sighand
;
1070 spin_lock_irq(&sighand
->siglock
);
1071 if (signal_group_exit(sig
))
1072 /* Another thread got here before we took the lock. */
1073 exit_code
= sig
->group_exit_code
;
1075 sig
->group_exit_code
= exit_code
;
1076 sig
->flags
= SIGNAL_GROUP_EXIT
;
1077 zap_other_threads(current
);
1079 spin_unlock_irq(&sighand
->siglock
);
1087 * this kills every thread in the thread group. Note that any externally
1088 * wait4()-ing process will get the correct exit code - even if this
1089 * thread is not the thread group leader.
1091 SYSCALL_DEFINE1(exit_group
, int, error_code
)
1093 do_group_exit((error_code
& 0xff) << 8);
1099 enum pid_type wo_type
;
1103 struct siginfo __user
*wo_info
;
1104 int __user
*wo_stat
;
1105 struct rusage __user
*wo_rusage
;
1107 wait_queue_t child_wait
;
1112 struct pid
*task_pid_type(struct task_struct
*task
, enum pid_type type
)
1114 if (type
!= PIDTYPE_PID
)
1115 task
= task
->group_leader
;
1116 return task
->pids
[type
].pid
;
1119 static int eligible_pid(struct wait_opts
*wo
, struct task_struct
*p
)
1121 return wo
->wo_type
== PIDTYPE_MAX
||
1122 task_pid_type(p
, wo
->wo_type
) == wo
->wo_pid
;
1125 static int eligible_child(struct wait_opts
*wo
, struct task_struct
*p
)
1127 if (!eligible_pid(wo
, p
))
1129 /* Wait for all children (clone and not) if __WALL is set;
1130 * otherwise, wait for clone children *only* if __WCLONE is
1131 * set; otherwise, wait for non-clone children *only*. (Note:
1132 * A "clone" child here is one that reports to its parent
1133 * using a signal other than SIGCHLD.) */
1134 if (((p
->exit_signal
!= SIGCHLD
) ^ !!(wo
->wo_flags
& __WCLONE
))
1135 && !(wo
->wo_flags
& __WALL
))
1141 static int wait_noreap_copyout(struct wait_opts
*wo
, struct task_struct
*p
,
1142 pid_t pid
, uid_t uid
, int why
, int status
)
1144 struct siginfo __user
*infop
;
1145 int retval
= wo
->wo_rusage
1146 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1149 infop
= wo
->wo_info
;
1152 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1154 retval
= put_user(0, &infop
->si_errno
);
1156 retval
= put_user((short)why
, &infop
->si_code
);
1158 retval
= put_user(pid
, &infop
->si_pid
);
1160 retval
= put_user(uid
, &infop
->si_uid
);
1162 retval
= put_user(status
, &infop
->si_status
);
1170 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1171 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1172 * the lock and this task is uninteresting. If we return nonzero, we have
1173 * released the lock and the system call should return.
1175 static int wait_task_zombie(struct wait_opts
*wo
, struct task_struct
*p
)
1177 unsigned long state
;
1178 int retval
, status
, traced
;
1179 pid_t pid
= task_pid_vnr(p
);
1180 uid_t uid
= __task_cred(p
)->uid
;
1181 struct siginfo __user
*infop
;
1183 if (!likely(wo
->wo_flags
& WEXITED
))
1186 if (unlikely(wo
->wo_flags
& WNOWAIT
)) {
1187 int exit_code
= p
->exit_code
;
1191 read_unlock(&tasklist_lock
);
1192 if ((exit_code
& 0x7f) == 0) {
1194 status
= exit_code
>> 8;
1196 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1197 status
= exit_code
& 0x7f;
1199 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, status
);
1203 * Try to move the task's state to DEAD
1204 * only one thread is allowed to do this:
1206 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1207 if (state
!= EXIT_ZOMBIE
) {
1208 BUG_ON(state
!= EXIT_DEAD
);
1212 traced
= ptrace_reparented(p
);
1214 * It can be ptraced but not reparented, check
1215 * !task_detached() to filter out sub-threads.
1217 if (likely(!traced
) && likely(!task_detached(p
))) {
1218 struct signal_struct
*psig
;
1219 struct signal_struct
*sig
;
1220 unsigned long maxrss
;
1221 cputime_t tgutime
, tgstime
;
1224 * The resource counters for the group leader are in its
1225 * own task_struct. Those for dead threads in the group
1226 * are in its signal_struct, as are those for the child
1227 * processes it has previously reaped. All these
1228 * accumulate in the parent's signal_struct c* fields.
1230 * We don't bother to take a lock here to protect these
1231 * p->signal fields, because they are only touched by
1232 * __exit_signal, which runs with tasklist_lock
1233 * write-locked anyway, and so is excluded here. We do
1234 * need to protect the access to parent->signal fields,
1235 * as other threads in the parent group can be right
1236 * here reaping other children at the same time.
1238 * We use thread_group_times() to get times for the thread
1239 * group, which consolidates times for all threads in the
1240 * group including the group leader.
1242 thread_group_times(p
, &tgutime
, &tgstime
);
1243 spin_lock_irq(&p
->real_parent
->sighand
->siglock
);
1244 psig
= p
->real_parent
->signal
;
1247 cputime_add(psig
->cutime
,
1248 cputime_add(tgutime
,
1251 cputime_add(psig
->cstime
,
1252 cputime_add(tgstime
,
1255 cputime_add(psig
->cgtime
,
1256 cputime_add(p
->gtime
,
1257 cputime_add(sig
->gtime
,
1260 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1262 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1264 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1266 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1268 task_io_get_inblock(p
) +
1269 sig
->inblock
+ sig
->cinblock
;
1271 task_io_get_oublock(p
) +
1272 sig
->oublock
+ sig
->coublock
;
1273 maxrss
= max(sig
->maxrss
, sig
->cmaxrss
);
1274 if (psig
->cmaxrss
< maxrss
)
1275 psig
->cmaxrss
= maxrss
;
1276 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1277 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1278 spin_unlock_irq(&p
->real_parent
->sighand
->siglock
);
1282 * Now we are sure this task is interesting, and no other
1283 * thread can reap it because we set its state to EXIT_DEAD.
1285 read_unlock(&tasklist_lock
);
1287 retval
= wo
->wo_rusage
1288 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1289 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1290 ? p
->signal
->group_exit_code
: p
->exit_code
;
1291 if (!retval
&& wo
->wo_stat
)
1292 retval
= put_user(status
, wo
->wo_stat
);
1294 infop
= wo
->wo_info
;
1295 if (!retval
&& infop
)
1296 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1297 if (!retval
&& infop
)
1298 retval
= put_user(0, &infop
->si_errno
);
1299 if (!retval
&& infop
) {
1302 if ((status
& 0x7f) == 0) {
1306 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1309 retval
= put_user((short)why
, &infop
->si_code
);
1311 retval
= put_user(status
, &infop
->si_status
);
1313 if (!retval
&& infop
)
1314 retval
= put_user(pid
, &infop
->si_pid
);
1315 if (!retval
&& infop
)
1316 retval
= put_user(uid
, &infop
->si_uid
);
1321 write_lock_irq(&tasklist_lock
);
1322 /* We dropped tasklist, ptracer could die and untrace */
1325 * If this is not a detached task, notify the parent.
1326 * If it's still not detached after that, don't release
1329 if (!task_detached(p
)) {
1330 do_notify_parent(p
, p
->exit_signal
);
1331 if (!task_detached(p
)) {
1332 p
->exit_state
= EXIT_ZOMBIE
;
1336 write_unlock_irq(&tasklist_lock
);
1344 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1347 if (task_is_stopped_or_traced(p
))
1348 return &p
->exit_code
;
1350 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1351 return &p
->signal
->group_exit_code
;
1357 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1358 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1359 * the lock and this task is uninteresting. If we return nonzero, we have
1360 * released the lock and the system call should return.
1362 static int wait_task_stopped(struct wait_opts
*wo
,
1363 int ptrace
, struct task_struct
*p
)
1365 struct siginfo __user
*infop
;
1366 int retval
, exit_code
, *p_code
, why
;
1367 uid_t uid
= 0; /* unneeded, required by compiler */
1371 * Traditionally we see ptrace'd stopped tasks regardless of options.
1373 if (!ptrace
&& !(wo
->wo_flags
& WUNTRACED
))
1377 spin_lock_irq(&p
->sighand
->siglock
);
1379 p_code
= task_stopped_code(p
, ptrace
);
1380 if (unlikely(!p_code
))
1383 exit_code
= *p_code
;
1387 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1390 /* don't need the RCU readlock here as we're holding a spinlock */
1391 uid
= __task_cred(p
)->uid
;
1393 spin_unlock_irq(&p
->sighand
->siglock
);
1398 * Now we are pretty sure this task is interesting.
1399 * Make sure it doesn't get reaped out from under us while we
1400 * give up the lock and then examine it below. We don't want to
1401 * keep holding onto the tasklist_lock while we call getrusage and
1402 * possibly take page faults for user memory.
1405 pid
= task_pid_vnr(p
);
1406 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1407 read_unlock(&tasklist_lock
);
1409 if (unlikely(wo
->wo_flags
& WNOWAIT
))
1410 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, exit_code
);
1412 retval
= wo
->wo_rusage
1413 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1414 if (!retval
&& wo
->wo_stat
)
1415 retval
= put_user((exit_code
<< 8) | 0x7f, wo
->wo_stat
);
1417 infop
= wo
->wo_info
;
1418 if (!retval
&& infop
)
1419 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1420 if (!retval
&& infop
)
1421 retval
= put_user(0, &infop
->si_errno
);
1422 if (!retval
&& infop
)
1423 retval
= put_user((short)why
, &infop
->si_code
);
1424 if (!retval
&& infop
)
1425 retval
= put_user(exit_code
, &infop
->si_status
);
1426 if (!retval
&& infop
)
1427 retval
= put_user(pid
, &infop
->si_pid
);
1428 if (!retval
&& infop
)
1429 retval
= put_user(uid
, &infop
->si_uid
);
1439 * Handle do_wait work for one task in a live, non-stopped state.
1440 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1441 * the lock and this task is uninteresting. If we return nonzero, we have
1442 * released the lock and the system call should return.
1444 static int wait_task_continued(struct wait_opts
*wo
, struct task_struct
*p
)
1450 if (!unlikely(wo
->wo_flags
& WCONTINUED
))
1453 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1456 spin_lock_irq(&p
->sighand
->siglock
);
1457 /* Re-check with the lock held. */
1458 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1459 spin_unlock_irq(&p
->sighand
->siglock
);
1462 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1463 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1464 uid
= __task_cred(p
)->uid
;
1465 spin_unlock_irq(&p
->sighand
->siglock
);
1467 pid
= task_pid_vnr(p
);
1469 read_unlock(&tasklist_lock
);
1472 retval
= wo
->wo_rusage
1473 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1475 if (!retval
&& wo
->wo_stat
)
1476 retval
= put_user(0xffff, wo
->wo_stat
);
1480 retval
= wait_noreap_copyout(wo
, p
, pid
, uid
,
1481 CLD_CONTINUED
, SIGCONT
);
1482 BUG_ON(retval
== 0);
1489 * Consider @p for a wait by @parent.
1491 * -ECHILD should be in ->notask_error before the first call.
1492 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1493 * Returns zero if the search for a child should continue;
1494 * then ->notask_error is 0 if @p is an eligible child,
1495 * or another error from security_task_wait(), or still -ECHILD.
1497 static int wait_consider_task(struct wait_opts
*wo
, int ptrace
,
1498 struct task_struct
*p
)
1500 int ret
= eligible_child(wo
, p
);
1504 ret
= security_task_wait(p
);
1505 if (unlikely(ret
< 0)) {
1507 * If we have not yet seen any eligible child,
1508 * then let this error code replace -ECHILD.
1509 * A permission error will give the user a clue
1510 * to look for security policy problems, rather
1511 * than for mysterious wait bugs.
1513 if (wo
->notask_error
)
1514 wo
->notask_error
= ret
;
1518 if (likely(!ptrace
) && unlikely(task_ptrace(p
))) {
1520 * This child is hidden by ptrace.
1521 * We aren't allowed to see it now, but eventually we will.
1523 wo
->notask_error
= 0;
1527 if (p
->exit_state
== EXIT_DEAD
)
1531 * We don't reap group leaders with subthreads.
1533 if (p
->exit_state
== EXIT_ZOMBIE
&& !delay_group_leader(p
))
1534 return wait_task_zombie(wo
, p
);
1537 * It's stopped or running now, so it might
1538 * later continue, exit, or stop again.
1540 wo
->notask_error
= 0;
1542 if (task_stopped_code(p
, ptrace
))
1543 return wait_task_stopped(wo
, ptrace
, p
);
1545 return wait_task_continued(wo
, p
);
1549 * Do the work of do_wait() for one thread in the group, @tsk.
1551 * -ECHILD should be in ->notask_error before the first call.
1552 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1553 * Returns zero if the search for a child should continue; then
1554 * ->notask_error is 0 if there were any eligible children,
1555 * or another error from security_task_wait(), or still -ECHILD.
1557 static int do_wait_thread(struct wait_opts
*wo
, struct task_struct
*tsk
)
1559 struct task_struct
*p
;
1561 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1562 int ret
= wait_consider_task(wo
, 0, p
);
1570 static int ptrace_do_wait(struct wait_opts
*wo
, struct task_struct
*tsk
)
1572 struct task_struct
*p
;
1574 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1575 int ret
= wait_consider_task(wo
, 1, p
);
1583 static int child_wait_callback(wait_queue_t
*wait
, unsigned mode
,
1584 int sync
, void *key
)
1586 struct wait_opts
*wo
= container_of(wait
, struct wait_opts
,
1588 struct task_struct
*p
= key
;
1590 if (!eligible_pid(wo
, p
))
1593 if ((wo
->wo_flags
& __WNOTHREAD
) && wait
->private != p
->parent
)
1596 return default_wake_function(wait
, mode
, sync
, key
);
1599 void __wake_up_parent(struct task_struct
*p
, struct task_struct
*parent
)
1601 __wake_up_sync_key(&parent
->signal
->wait_chldexit
,
1602 TASK_INTERRUPTIBLE
, 1, p
);
1605 static long do_wait(struct wait_opts
*wo
)
1607 struct task_struct
*tsk
;
1610 trace_sched_process_wait(wo
->wo_pid
);
1612 init_waitqueue_func_entry(&wo
->child_wait
, child_wait_callback
);
1613 wo
->child_wait
.private = current
;
1614 add_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1617 * If there is nothing that can match our critiera just get out.
1618 * We will clear ->notask_error to zero if we see any child that
1619 * might later match our criteria, even if we are not able to reap
1622 wo
->notask_error
= -ECHILD
;
1623 if ((wo
->wo_type
< PIDTYPE_MAX
) &&
1624 (!wo
->wo_pid
|| hlist_empty(&wo
->wo_pid
->tasks
[wo
->wo_type
])))
1627 set_current_state(TASK_INTERRUPTIBLE
);
1628 read_lock(&tasklist_lock
);
1631 retval
= do_wait_thread(wo
, tsk
);
1635 retval
= ptrace_do_wait(wo
, tsk
);
1639 if (wo
->wo_flags
& __WNOTHREAD
)
1641 } while_each_thread(current
, tsk
);
1642 read_unlock(&tasklist_lock
);
1645 retval
= wo
->notask_error
;
1646 if (!retval
&& !(wo
->wo_flags
& WNOHANG
)) {
1647 retval
= -ERESTARTSYS
;
1648 if (!signal_pending(current
)) {
1654 __set_current_state(TASK_RUNNING
);
1655 remove_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1659 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1660 infop
, int, options
, struct rusage __user
*, ru
)
1662 struct wait_opts wo
;
1663 struct pid
*pid
= NULL
;
1667 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1669 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1682 type
= PIDTYPE_PGID
;
1690 if (type
< PIDTYPE_MAX
)
1691 pid
= find_get_pid(upid
);
1695 wo
.wo_flags
= options
;
1705 * For a WNOHANG return, clear out all the fields
1706 * we would set so the user can easily tell the
1710 ret
= put_user(0, &infop
->si_signo
);
1712 ret
= put_user(0, &infop
->si_errno
);
1714 ret
= put_user(0, &infop
->si_code
);
1716 ret
= put_user(0, &infop
->si_pid
);
1718 ret
= put_user(0, &infop
->si_uid
);
1720 ret
= put_user(0, &infop
->si_status
);
1725 /* avoid REGPARM breakage on x86: */
1726 asmlinkage_protect(5, ret
, which
, upid
, infop
, options
, ru
);
1730 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1731 int, options
, struct rusage __user
*, ru
)
1733 struct wait_opts wo
;
1734 struct pid
*pid
= NULL
;
1738 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1739 __WNOTHREAD
|__WCLONE
|__WALL
))
1744 else if (upid
< 0) {
1745 type
= PIDTYPE_PGID
;
1746 pid
= find_get_pid(-upid
);
1747 } else if (upid
== 0) {
1748 type
= PIDTYPE_PGID
;
1749 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1750 } else /* upid > 0 */ {
1752 pid
= find_get_pid(upid
);
1757 wo
.wo_flags
= options
| WEXITED
;
1759 wo
.wo_stat
= stat_addr
;
1764 /* avoid REGPARM breakage on x86: */
1765 asmlinkage_protect(4, ret
, upid
, stat_addr
, options
, ru
);
1769 #ifdef __ARCH_WANT_SYS_WAITPID
1772 * sys_waitpid() remains for compatibility. waitpid() should be
1773 * implemented by calling sys_wait4() from libc.a.
1775 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1777 return sys_wait4(pid
, stat_addr
, options
, NULL
);
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