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>
53 #include <linux/oom.h>
54 #include <linux/writeback.h>
55 #include <linux/shm.h>
57 #include <asm/uaccess.h>
58 #include <asm/unistd.h>
59 #include <asm/pgtable.h>
60 #include <asm/mmu_context.h>
62 static void exit_mm(struct task_struct
* tsk
);
64 static void __unhash_process(struct task_struct
*p
, bool group_dead
)
67 detach_pid(p
, PIDTYPE_PID
);
69 detach_pid(p
, PIDTYPE_PGID
);
70 detach_pid(p
, PIDTYPE_SID
);
72 list_del_rcu(&p
->tasks
);
73 list_del_init(&p
->sibling
);
74 __this_cpu_dec(process_counts
);
76 * If we are the last child process in a pid namespace to be
77 * reaped, notify the reaper sleeping zap_pid_ns_processes().
79 if (IS_ENABLED(CONFIG_PID_NS
)) {
80 struct task_struct
*parent
= p
->real_parent
;
82 if ((task_active_pid_ns(parent
)->child_reaper
== parent
) &&
83 list_empty(&parent
->children
) &&
84 (parent
->flags
& PF_EXITING
))
85 wake_up_process(parent
);
88 list_del_rcu(&p
->thread_group
);
92 * This function expects the tasklist_lock write-locked.
94 static void __exit_signal(struct task_struct
*tsk
)
96 struct signal_struct
*sig
= tsk
->signal
;
97 bool group_dead
= thread_group_leader(tsk
);
98 struct sighand_struct
*sighand
;
99 struct tty_struct
*uninitialized_var(tty
);
101 sighand
= rcu_dereference_check(tsk
->sighand
,
102 lockdep_tasklist_lock_is_held());
103 spin_lock(&sighand
->siglock
);
105 posix_cpu_timers_exit(tsk
);
107 posix_cpu_timers_exit_group(tsk
);
112 * This can only happen if the caller is de_thread().
113 * FIXME: this is the temporary hack, we should teach
114 * posix-cpu-timers to handle this case correctly.
116 if (unlikely(has_group_leader_pid(tsk
)))
117 posix_cpu_timers_exit_group(tsk
);
120 * If there is any task waiting for the group exit
123 if (sig
->notify_count
> 0 && !--sig
->notify_count
)
124 wake_up_process(sig
->group_exit_task
);
126 if (tsk
== sig
->curr_target
)
127 sig
->curr_target
= next_thread(tsk
);
129 * Accumulate here the counters for all threads but the
130 * group leader as they die, so they can be added into
131 * the process-wide totals when those are taken.
132 * The group leader stays around as a zombie as long
133 * as there are other threads. When it gets reaped,
134 * the exit.c code will add its counts into these totals.
135 * We won't ever get here for the group leader, since it
136 * will have been the last reference on the signal_struct.
138 sig
->utime
+= tsk
->utime
;
139 sig
->stime
+= tsk
->stime
;
140 sig
->gtime
+= tsk
->gtime
;
141 sig
->min_flt
+= tsk
->min_flt
;
142 sig
->maj_flt
+= tsk
->maj_flt
;
143 sig
->nvcsw
+= tsk
->nvcsw
;
144 sig
->nivcsw
+= tsk
->nivcsw
;
145 sig
->inblock
+= task_io_get_inblock(tsk
);
146 sig
->oublock
+= task_io_get_oublock(tsk
);
147 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
148 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
152 __unhash_process(tsk
, group_dead
);
155 * Do this under ->siglock, we can race with another thread
156 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
158 flush_sigqueue(&tsk
->pending
);
160 spin_unlock(&sighand
->siglock
);
162 __cleanup_sighand(sighand
);
163 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
165 flush_sigqueue(&sig
->shared_pending
);
170 static void delayed_put_task_struct(struct rcu_head
*rhp
)
172 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
174 perf_event_delayed_put(tsk
);
175 trace_sched_process_free(tsk
);
176 put_task_struct(tsk
);
180 void release_task(struct task_struct
* p
)
182 struct task_struct
*leader
;
185 /* don't need to get the RCU readlock here - the process is dead and
186 * can't be modifying its own credentials. But shut RCU-lockdep up */
188 atomic_dec(&__task_cred(p
)->user
->processes
);
193 write_lock_irq(&tasklist_lock
);
194 ptrace_release_task(p
);
198 * If we are the last non-leader member of the thread
199 * group, and the leader is zombie, then notify the
200 * group leader's parent process. (if it wants notification.)
203 leader
= p
->group_leader
;
204 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
206 * If we were the last child thread and the leader has
207 * exited already, and the leader's parent ignores SIGCHLD,
208 * then we are the one who should release the leader.
210 zap_leader
= do_notify_parent(leader
, leader
->exit_signal
);
212 leader
->exit_state
= EXIT_DEAD
;
215 write_unlock_irq(&tasklist_lock
);
217 call_rcu(&p
->rcu
, delayed_put_task_struct
);
220 if (unlikely(zap_leader
))
225 * This checks not only the pgrp, but falls back on the pid if no
226 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
229 * The caller must hold rcu lock or the tasklist lock.
231 struct pid
*session_of_pgrp(struct pid
*pgrp
)
233 struct task_struct
*p
;
234 struct pid
*sid
= NULL
;
236 p
= pid_task(pgrp
, PIDTYPE_PGID
);
238 p
= pid_task(pgrp
, PIDTYPE_PID
);
240 sid
= task_session(p
);
246 * Determine if a process group is "orphaned", according to the POSIX
247 * definition in 2.2.2.52. Orphaned process groups are not to be affected
248 * by terminal-generated stop signals. Newly orphaned process groups are
249 * to receive a SIGHUP and a SIGCONT.
251 * "I ask you, have you ever known what it is to be an orphan?"
253 static int will_become_orphaned_pgrp(struct pid
*pgrp
, struct task_struct
*ignored_task
)
255 struct task_struct
*p
;
257 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
258 if ((p
== ignored_task
) ||
259 (p
->exit_state
&& thread_group_empty(p
)) ||
260 is_global_init(p
->real_parent
))
263 if (task_pgrp(p
->real_parent
) != pgrp
&&
264 task_session(p
->real_parent
) == task_session(p
))
266 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
271 int is_current_pgrp_orphaned(void)
275 read_lock(&tasklist_lock
);
276 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
277 read_unlock(&tasklist_lock
);
282 static bool has_stopped_jobs(struct pid
*pgrp
)
284 struct task_struct
*p
;
286 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
287 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
289 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
295 * Check to see if any process groups have become orphaned as
296 * a result of our exiting, and if they have any stopped jobs,
297 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
300 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
302 struct pid
*pgrp
= task_pgrp(tsk
);
303 struct task_struct
*ignored_task
= tsk
;
306 /* exit: our father is in a different pgrp than
307 * we are and we were the only connection outside.
309 parent
= tsk
->real_parent
;
311 /* reparent: our child is in a different pgrp than
312 * we are, and it was the only connection outside.
316 if (task_pgrp(parent
) != pgrp
&&
317 task_session(parent
) == task_session(tsk
) &&
318 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
319 has_stopped_jobs(pgrp
)) {
320 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
321 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
326 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
328 * If a kernel thread is launched as a result of a system call, or if
329 * it ever exits, it should generally reparent itself to kthreadd so it
330 * isn't in the way of other processes and is correctly cleaned up on exit.
332 * The various task state such as scheduling policy and priority may have
333 * been inherited from a user process, so we reset them to sane values here.
335 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
337 static void reparent_to_kthreadd(void)
339 write_lock_irq(&tasklist_lock
);
341 ptrace_unlink(current
);
342 /* Reparent to init */
343 current
->real_parent
= current
->parent
= kthreadd_task
;
344 list_move_tail(¤t
->sibling
, ¤t
->real_parent
->children
);
346 /* Set the exit signal to SIGCHLD so we signal init on exit */
347 current
->exit_signal
= SIGCHLD
;
349 if (task_nice(current
) < 0)
350 set_user_nice(current
, 0);
354 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
355 sizeof(current
->signal
->rlim
));
357 atomic_inc(&init_cred
.usage
);
358 commit_creds(&init_cred
);
359 write_unlock_irq(&tasklist_lock
);
362 void __set_special_pids(struct pid
*pid
)
364 struct task_struct
*curr
= current
->group_leader
;
366 if (task_session(curr
) != pid
)
367 change_pid(curr
, PIDTYPE_SID
, pid
);
369 if (task_pgrp(curr
) != pid
)
370 change_pid(curr
, PIDTYPE_PGID
, pid
);
373 static void set_special_pids(struct pid
*pid
)
375 write_lock_irq(&tasklist_lock
);
376 __set_special_pids(pid
);
377 write_unlock_irq(&tasklist_lock
);
381 * Let kernel threads use this to say that they allow a certain signal.
382 * Must not be used if kthread was cloned with CLONE_SIGHAND.
384 int allow_signal(int sig
)
386 if (!valid_signal(sig
) || sig
< 1)
389 spin_lock_irq(¤t
->sighand
->siglock
);
390 /* This is only needed for daemonize()'ed kthreads */
391 sigdelset(¤t
->blocked
, sig
);
393 * Kernel threads handle their own signals. Let the signal code
394 * know it'll be handled, so that they don't get converted to
395 * SIGKILL or just silently dropped.
397 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
399 spin_unlock_irq(¤t
->sighand
->siglock
);
403 EXPORT_SYMBOL(allow_signal
);
405 int disallow_signal(int sig
)
407 if (!valid_signal(sig
) || sig
< 1)
410 spin_lock_irq(¤t
->sighand
->siglock
);
411 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= SIG_IGN
;
413 spin_unlock_irq(¤t
->sighand
->siglock
);
417 EXPORT_SYMBOL(disallow_signal
);
420 * Put all the gunge required to become a kernel thread without
421 * attached user resources in one place where it belongs.
424 void daemonize(const char *name
, ...)
429 va_start(args
, name
);
430 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
434 * If we were started as result of loading a module, close all of the
435 * user space pages. We don't need them, and if we didn't close them
436 * they would be locked into memory.
440 * We don't want to get frozen, in case system-wide hibernation
441 * or suspend transition begins right now.
443 current
->flags
|= (PF_NOFREEZE
| PF_KTHREAD
);
445 if (current
->nsproxy
!= &init_nsproxy
) {
446 get_nsproxy(&init_nsproxy
);
447 switch_task_namespaces(current
, &init_nsproxy
);
449 set_special_pids(&init_struct_pid
);
450 proc_clear_tty(current
);
452 /* Block and flush all signals */
453 sigfillset(&blocked
);
454 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
455 flush_signals(current
);
457 /* Become as one with the init task */
459 daemonize_fs_struct();
461 current
->files
= init_task
.files
;
462 atomic_inc(¤t
->files
->count
);
464 reparent_to_kthreadd();
467 EXPORT_SYMBOL(daemonize
);
469 static void close_files(struct files_struct
* files
)
477 * It is safe to dereference the fd table without RCU or
478 * ->file_lock because this is the last reference to the
479 * files structure. But use RCU to shut RCU-lockdep up.
482 fdt
= files_fdtable(files
);
487 if (i
>= fdt
->max_fds
)
489 set
= fdt
->open_fds
[j
++];
492 struct file
* file
= xchg(&fdt
->fd
[i
], NULL
);
494 filp_close(file
, files
);
504 struct files_struct
*get_files_struct(struct task_struct
*task
)
506 struct files_struct
*files
;
511 atomic_inc(&files
->count
);
517 void put_files_struct(struct files_struct
*files
)
521 if (atomic_dec_and_test(&files
->count
)) {
524 * Free the fd and fdset arrays if we expanded them.
525 * If the fdtable was embedded, pass files for freeing
526 * at the end of the RCU grace period. Otherwise,
527 * you can free files immediately.
530 fdt
= files_fdtable(files
);
531 if (fdt
!= &files
->fdtab
)
532 kmem_cache_free(files_cachep
, files
);
538 void reset_files_struct(struct files_struct
*files
)
540 struct task_struct
*tsk
= current
;
541 struct files_struct
*old
;
547 put_files_struct(old
);
550 void exit_files(struct task_struct
*tsk
)
552 struct files_struct
* files
= tsk
->files
;
558 put_files_struct(files
);
562 #ifdef CONFIG_MM_OWNER
564 * A task is exiting. If it owned this mm, find a new owner for the mm.
566 void mm_update_next_owner(struct mm_struct
*mm
)
568 struct task_struct
*c
, *g
, *p
= current
;
572 * If the exiting or execing task is not the owner, it's
573 * someone else's problem.
578 * The current owner is exiting/execing and there are no other
579 * candidates. Do not leave the mm pointing to a possibly
580 * freed task structure.
582 if (atomic_read(&mm
->mm_users
) <= 1) {
587 read_lock(&tasklist_lock
);
589 * Search in the children
591 list_for_each_entry(c
, &p
->children
, sibling
) {
593 goto assign_new_owner
;
597 * Search in the siblings
599 list_for_each_entry(c
, &p
->real_parent
->children
, sibling
) {
601 goto assign_new_owner
;
605 * Search through everything else. We should not get
608 do_each_thread(g
, c
) {
610 goto assign_new_owner
;
611 } while_each_thread(g
, c
);
613 read_unlock(&tasklist_lock
);
615 * We found no owner yet mm_users > 1: this implies that we are
616 * most likely racing with swapoff (try_to_unuse()) or /proc or
617 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
626 * The task_lock protects c->mm from changing.
627 * We always want mm->owner->mm == mm
631 * Delay read_unlock() till we have the task_lock()
632 * to ensure that c does not slip away underneath us
634 read_unlock(&tasklist_lock
);
644 #endif /* CONFIG_MM_OWNER */
647 * Turn us into a lazy TLB process if we
650 static void exit_mm(struct task_struct
* tsk
)
652 struct mm_struct
*mm
= tsk
->mm
;
653 struct core_state
*core_state
;
660 * Serialize with any possible pending coredump.
661 * We must hold mmap_sem around checking core_state
662 * and clearing tsk->mm. The core-inducing thread
663 * will increment ->nr_threads for each thread in the
664 * group with ->mm != NULL.
666 down_read(&mm
->mmap_sem
);
667 core_state
= mm
->core_state
;
669 struct core_thread self
;
670 up_read(&mm
->mmap_sem
);
673 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
675 * Implies mb(), the result of xchg() must be visible
676 * to core_state->dumper.
678 if (atomic_dec_and_test(&core_state
->nr_threads
))
679 complete(&core_state
->startup
);
682 set_task_state(tsk
, TASK_UNINTERRUPTIBLE
);
683 if (!self
.task
) /* see coredump_finish() */
687 __set_task_state(tsk
, TASK_RUNNING
);
688 down_read(&mm
->mmap_sem
);
690 atomic_inc(&mm
->mm_count
);
691 BUG_ON(mm
!= tsk
->active_mm
);
692 /* more a memory barrier than a real lock */
695 up_read(&mm
->mmap_sem
);
696 enter_lazy_tlb(mm
, current
);
698 mm_update_next_owner(mm
);
703 * When we die, we re-parent all our children, and try to:
704 * 1. give them to another thread in our thread group, if such a member exists
705 * 2. give it to the first ancestor process which prctl'd itself as a
706 * child_subreaper for its children (like a service manager)
707 * 3. give it to the init process (PID 1) in our pid namespace
709 static struct task_struct
*find_new_reaper(struct task_struct
*father
)
710 __releases(&tasklist_lock
)
711 __acquires(&tasklist_lock
)
713 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
714 struct task_struct
*thread
;
717 while_each_thread(father
, thread
) {
718 if (thread
->flags
& PF_EXITING
)
720 if (unlikely(pid_ns
->child_reaper
== father
))
721 pid_ns
->child_reaper
= thread
;
725 if (unlikely(pid_ns
->child_reaper
== father
)) {
726 write_unlock_irq(&tasklist_lock
);
727 if (unlikely(pid_ns
== &init_pid_ns
)) {
728 panic("Attempted to kill init! exitcode=0x%08x\n",
729 father
->signal
->group_exit_code
?:
733 zap_pid_ns_processes(pid_ns
);
734 write_lock_irq(&tasklist_lock
);
735 } else if (father
->signal
->has_child_subreaper
) {
736 struct task_struct
*reaper
;
739 * Find the first ancestor marked as child_subreaper.
740 * Note that the code below checks same_thread_group(reaper,
741 * pid_ns->child_reaper). This is what we need to DTRT in a
742 * PID namespace. However we still need the check above, see
743 * http://marc.info/?l=linux-kernel&m=131385460420380
745 for (reaper
= father
->real_parent
;
746 reaper
!= &init_task
;
747 reaper
= reaper
->real_parent
) {
748 if (same_thread_group(reaper
, pid_ns
->child_reaper
))
750 if (!reaper
->signal
->is_child_subreaper
)
754 if (!(thread
->flags
& PF_EXITING
))
756 } while_each_thread(reaper
, thread
);
760 return pid_ns
->child_reaper
;
764 * Any that need to be release_task'd are put on the @dead list.
766 static void reparent_leader(struct task_struct
*father
, struct task_struct
*p
,
767 struct list_head
*dead
)
769 list_move_tail(&p
->sibling
, &p
->real_parent
->children
);
771 if (p
->exit_state
== EXIT_DEAD
)
774 * If this is a threaded reparent there is no need to
775 * notify anyone anything has happened.
777 if (same_thread_group(p
->real_parent
, father
))
780 /* We don't want people slaying init. */
781 p
->exit_signal
= SIGCHLD
;
783 /* If it has exited notify the new parent about this child's death. */
785 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
786 if (do_notify_parent(p
, p
->exit_signal
)) {
787 p
->exit_state
= EXIT_DEAD
;
788 list_move_tail(&p
->sibling
, dead
);
792 kill_orphaned_pgrp(p
, father
);
795 static void forget_original_parent(struct task_struct
*father
)
797 struct task_struct
*p
, *n
, *reaper
;
798 LIST_HEAD(dead_children
);
800 write_lock_irq(&tasklist_lock
);
802 * Note that exit_ptrace() and find_new_reaper() might
803 * drop tasklist_lock and reacquire it.
806 reaper
= find_new_reaper(father
);
808 list_for_each_entry_safe(p
, n
, &father
->children
, sibling
) {
809 struct task_struct
*t
= p
;
811 t
->real_parent
= reaper
;
812 if (t
->parent
== father
) {
814 t
->parent
= t
->real_parent
;
816 if (t
->pdeath_signal
)
817 group_send_sig_info(t
->pdeath_signal
,
819 } while_each_thread(p
, t
);
820 reparent_leader(father
, p
, &dead_children
);
822 write_unlock_irq(&tasklist_lock
);
824 BUG_ON(!list_empty(&father
->children
));
826 list_for_each_entry_safe(p
, n
, &dead_children
, sibling
) {
827 list_del_init(&p
->sibling
);
833 * Send signals to all our closest relatives so that they know
834 * to properly mourn us..
836 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
841 * This does two things:
843 * A. Make init inherit all the child processes
844 * B. Check to see if any process groups have become orphaned
845 * as a result of our exiting, and if they have any stopped
846 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
848 forget_original_parent(tsk
);
849 exit_task_namespaces(tsk
);
851 write_lock_irq(&tasklist_lock
);
853 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
855 if (unlikely(tsk
->ptrace
)) {
856 int sig
= thread_group_leader(tsk
) &&
857 thread_group_empty(tsk
) &&
858 !ptrace_reparented(tsk
) ?
859 tsk
->exit_signal
: SIGCHLD
;
860 autoreap
= do_notify_parent(tsk
, sig
);
861 } else if (thread_group_leader(tsk
)) {
862 autoreap
= thread_group_empty(tsk
) &&
863 do_notify_parent(tsk
, tsk
->exit_signal
);
868 tsk
->exit_state
= autoreap
? EXIT_DEAD
: EXIT_ZOMBIE
;
870 /* mt-exec, de_thread() is waiting for group leader */
871 if (unlikely(tsk
->signal
->notify_count
< 0))
872 wake_up_process(tsk
->signal
->group_exit_task
);
873 write_unlock_irq(&tasklist_lock
);
875 /* If the process is dead, release it - nobody will wait for it */
880 #ifdef CONFIG_DEBUG_STACK_USAGE
881 static void check_stack_usage(void)
883 static DEFINE_SPINLOCK(low_water_lock
);
884 static int lowest_to_date
= THREAD_SIZE
;
887 free
= stack_not_used(current
);
889 if (free
>= lowest_to_date
)
892 spin_lock(&low_water_lock
);
893 if (free
< lowest_to_date
) {
894 printk(KERN_WARNING
"%s (%d) used greatest stack depth: "
896 current
->comm
, task_pid_nr(current
), free
);
897 lowest_to_date
= free
;
899 spin_unlock(&low_water_lock
);
902 static inline void check_stack_usage(void) {}
905 void do_exit(long code
)
907 struct task_struct
*tsk
= current
;
910 profile_task_exit(tsk
);
912 WARN_ON(blk_needs_flush_plug(tsk
));
914 if (unlikely(in_interrupt()))
915 panic("Aiee, killing interrupt handler!");
916 if (unlikely(!tsk
->pid
))
917 panic("Attempted to kill the idle task!");
920 * If do_exit is called because this processes oopsed, it's possible
921 * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
922 * continuing. Amongst other possible reasons, this is to prevent
923 * mm_release()->clear_child_tid() from writing to a user-controlled
928 ptrace_event(PTRACE_EVENT_EXIT
, code
);
930 validate_creds_for_do_exit(tsk
);
933 * We're taking recursive faults here in do_exit. Safest is to just
934 * leave this task alone and wait for reboot.
936 if (unlikely(tsk
->flags
& PF_EXITING
)) {
938 "Fixing recursive fault but reboot is needed!\n");
940 * We can do this unlocked here. The futex code uses
941 * this flag just to verify whether the pi state
942 * cleanup has been done or not. In the worst case it
943 * loops once more. We pretend that the cleanup was
944 * done as there is no way to return. Either the
945 * OWNER_DIED bit is set by now or we push the blocked
946 * task into the wait for ever nirwana as well.
948 tsk
->flags
|= PF_EXITPIDONE
;
949 set_current_state(TASK_UNINTERRUPTIBLE
);
953 exit_signals(tsk
); /* sets PF_EXITING */
955 * tsk->flags are checked in the futex code to protect against
956 * an exiting task cleaning up the robust pi futexes, and in
957 * task_work_add() to avoid the race with exit_task_work().
960 raw_spin_unlock_wait(&tsk
->pi_lock
);
964 if (unlikely(in_atomic()))
965 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
966 current
->comm
, task_pid_nr(current
),
969 acct_update_integrals(tsk
);
970 /* sync mm's RSS info before statistics gathering */
972 sync_mm_rss(tsk
->mm
);
973 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
975 hrtimer_cancel(&tsk
->signal
->real_timer
);
976 exit_itimers(tsk
->signal
);
978 setmax_mm_hiwater_rss(&tsk
->signal
->maxrss
, tsk
->mm
);
980 acct_collect(code
, group_dead
);
985 tsk
->exit_code
= code
;
986 taskstats_exit(tsk
, group_dead
);
992 trace_sched_process_exit(tsk
);
1002 * Flush inherited counters to the parent - before the parent
1003 * gets woken up by child-exit notifications.
1005 * because of cgroup mode, must be called before cgroup_exit()
1007 perf_event_exit_task(tsk
);
1009 cgroup_exit(tsk
, 1);
1012 disassociate_ctty(1);
1014 module_put(task_thread_info(tsk
)->exec_domain
->module
);
1016 proc_exit_connector(tsk
);
1019 * FIXME: do that only when needed, using sched_exit tracepoint
1021 ptrace_put_breakpoints(tsk
);
1023 exit_notify(tsk
, group_dead
);
1026 mpol_put(tsk
->mempolicy
);
1027 tsk
->mempolicy
= NULL
;
1031 if (unlikely(current
->pi_state_cache
))
1032 kfree(current
->pi_state_cache
);
1035 * Make sure we are holding no locks:
1037 debug_check_no_locks_held(tsk
);
1039 * We can do this unlocked here. The futex code uses this flag
1040 * just to verify whether the pi state cleanup has been done
1041 * or not. In the worst case it loops once more.
1043 tsk
->flags
|= PF_EXITPIDONE
;
1045 if (tsk
->io_context
)
1046 exit_io_context(tsk
);
1048 if (tsk
->splice_pipe
)
1049 __free_pipe_info(tsk
->splice_pipe
);
1051 validate_creds_for_do_exit(tsk
);
1054 if (tsk
->nr_dirtied
)
1055 __this_cpu_add(dirty_throttle_leaks
, tsk
->nr_dirtied
);
1059 * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
1060 * when the following two conditions become true.
1061 * - There is race condition of mmap_sem (It is acquired by
1063 * - SMI occurs before setting TASK_RUNINNG.
1064 * (or hypervisor of virtual machine switches to other guest)
1065 * As a result, we may become TASK_RUNNING after becoming TASK_DEAD
1067 * To avoid it, we have to wait for releasing tsk->pi_lock which
1068 * is held by try_to_wake_up()
1071 raw_spin_unlock_wait(&tsk
->pi_lock
);
1073 /* causes final put_task_struct in finish_task_switch(). */
1074 tsk
->state
= TASK_DEAD
;
1075 tsk
->flags
|= PF_NOFREEZE
; /* tell freezer to ignore us */
1078 /* Avoid "noreturn function does return". */
1080 cpu_relax(); /* For when BUG is null */
1083 EXPORT_SYMBOL_GPL(do_exit
);
1085 void complete_and_exit(struct completion
*comp
, long code
)
1093 EXPORT_SYMBOL(complete_and_exit
);
1095 SYSCALL_DEFINE1(exit
, int, error_code
)
1097 do_exit((error_code
&0xff)<<8);
1101 * Take down every thread in the group. This is called by fatal signals
1102 * as well as by sys_exit_group (below).
1105 do_group_exit(int exit_code
)
1107 struct signal_struct
*sig
= current
->signal
;
1109 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
1111 if (signal_group_exit(sig
))
1112 exit_code
= sig
->group_exit_code
;
1113 else if (!thread_group_empty(current
)) {
1114 struct sighand_struct
*const sighand
= current
->sighand
;
1115 spin_lock_irq(&sighand
->siglock
);
1116 if (signal_group_exit(sig
))
1117 /* Another thread got here before we took the lock. */
1118 exit_code
= sig
->group_exit_code
;
1120 sig
->group_exit_code
= exit_code
;
1121 sig
->flags
= SIGNAL_GROUP_EXIT
;
1122 zap_other_threads(current
);
1124 spin_unlock_irq(&sighand
->siglock
);
1132 * this kills every thread in the thread group. Note that any externally
1133 * wait4()-ing process will get the correct exit code - even if this
1134 * thread is not the thread group leader.
1136 SYSCALL_DEFINE1(exit_group
, int, error_code
)
1138 do_group_exit((error_code
& 0xff) << 8);
1144 enum pid_type wo_type
;
1148 struct siginfo __user
*wo_info
;
1149 int __user
*wo_stat
;
1150 struct rusage __user
*wo_rusage
;
1152 wait_queue_t child_wait
;
1157 struct pid
*task_pid_type(struct task_struct
*task
, enum pid_type type
)
1159 if (type
!= PIDTYPE_PID
)
1160 task
= task
->group_leader
;
1161 return task
->pids
[type
].pid
;
1164 static int eligible_pid(struct wait_opts
*wo
, struct task_struct
*p
)
1166 return wo
->wo_type
== PIDTYPE_MAX
||
1167 task_pid_type(p
, wo
->wo_type
) == wo
->wo_pid
;
1170 static int eligible_child(struct wait_opts
*wo
, struct task_struct
*p
)
1172 if (!eligible_pid(wo
, p
))
1174 /* Wait for all children (clone and not) if __WALL is set;
1175 * otherwise, wait for clone children *only* if __WCLONE is
1176 * set; otherwise, wait for non-clone children *only*. (Note:
1177 * A "clone" child here is one that reports to its parent
1178 * using a signal other than SIGCHLD.) */
1179 if (((p
->exit_signal
!= SIGCHLD
) ^ !!(wo
->wo_flags
& __WCLONE
))
1180 && !(wo
->wo_flags
& __WALL
))
1186 static int wait_noreap_copyout(struct wait_opts
*wo
, struct task_struct
*p
,
1187 pid_t pid
, uid_t uid
, int why
, int status
)
1189 struct siginfo __user
*infop
;
1190 int retval
= wo
->wo_rusage
1191 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1194 infop
= wo
->wo_info
;
1197 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1199 retval
= put_user(0, &infop
->si_errno
);
1201 retval
= put_user((short)why
, &infop
->si_code
);
1203 retval
= put_user(pid
, &infop
->si_pid
);
1205 retval
= put_user(uid
, &infop
->si_uid
);
1207 retval
= put_user(status
, &infop
->si_status
);
1215 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1216 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1217 * the lock and this task is uninteresting. If we return nonzero, we have
1218 * released the lock and the system call should return.
1220 static int wait_task_zombie(struct wait_opts
*wo
, struct task_struct
*p
)
1222 unsigned long state
;
1223 int retval
, status
, traced
;
1224 pid_t pid
= task_pid_vnr(p
);
1225 uid_t uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1226 struct siginfo __user
*infop
;
1228 if (!likely(wo
->wo_flags
& WEXITED
))
1231 if (unlikely(wo
->wo_flags
& WNOWAIT
)) {
1232 int exit_code
= p
->exit_code
;
1236 read_unlock(&tasklist_lock
);
1237 if ((exit_code
& 0x7f) == 0) {
1239 status
= exit_code
>> 8;
1241 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1242 status
= exit_code
& 0x7f;
1244 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, status
);
1248 * Try to move the task's state to DEAD
1249 * only one thread is allowed to do this:
1251 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1252 if (state
!= EXIT_ZOMBIE
) {
1253 BUG_ON(state
!= EXIT_DEAD
);
1257 traced
= ptrace_reparented(p
);
1259 * It can be ptraced but not reparented, check
1260 * thread_group_leader() to filter out sub-threads.
1262 if (likely(!traced
) && thread_group_leader(p
)) {
1263 struct signal_struct
*psig
;
1264 struct signal_struct
*sig
;
1265 unsigned long maxrss
;
1266 cputime_t tgutime
, tgstime
;
1269 * The resource counters for the group leader are in its
1270 * own task_struct. Those for dead threads in the group
1271 * are in its signal_struct, as are those for the child
1272 * processes it has previously reaped. All these
1273 * accumulate in the parent's signal_struct c* fields.
1275 * We don't bother to take a lock here to protect these
1276 * p->signal fields, because they are only touched by
1277 * __exit_signal, which runs with tasklist_lock
1278 * write-locked anyway, and so is excluded here. We do
1279 * need to protect the access to parent->signal fields,
1280 * as other threads in the parent group can be right
1281 * here reaping other children at the same time.
1283 * We use thread_group_times() to get times for the thread
1284 * group, which consolidates times for all threads in the
1285 * group including the group leader.
1287 thread_group_times(p
, &tgutime
, &tgstime
);
1288 spin_lock_irq(&p
->real_parent
->sighand
->siglock
);
1289 psig
= p
->real_parent
->signal
;
1291 psig
->cutime
+= tgutime
+ sig
->cutime
;
1292 psig
->cstime
+= tgstime
+ sig
->cstime
;
1293 psig
->cgtime
+= p
->gtime
+ sig
->gtime
+ sig
->cgtime
;
1295 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1297 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1299 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1301 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1303 task_io_get_inblock(p
) +
1304 sig
->inblock
+ sig
->cinblock
;
1306 task_io_get_oublock(p
) +
1307 sig
->oublock
+ sig
->coublock
;
1308 maxrss
= max(sig
->maxrss
, sig
->cmaxrss
);
1309 if (psig
->cmaxrss
< maxrss
)
1310 psig
->cmaxrss
= maxrss
;
1311 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1312 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1313 spin_unlock_irq(&p
->real_parent
->sighand
->siglock
);
1317 * Now we are sure this task is interesting, and no other
1318 * thread can reap it because we set its state to EXIT_DEAD.
1320 read_unlock(&tasklist_lock
);
1322 retval
= wo
->wo_rusage
1323 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1324 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1325 ? p
->signal
->group_exit_code
: p
->exit_code
;
1326 if (!retval
&& wo
->wo_stat
)
1327 retval
= put_user(status
, wo
->wo_stat
);
1329 infop
= wo
->wo_info
;
1330 if (!retval
&& infop
)
1331 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1332 if (!retval
&& infop
)
1333 retval
= put_user(0, &infop
->si_errno
);
1334 if (!retval
&& infop
) {
1337 if ((status
& 0x7f) == 0) {
1341 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1344 retval
= put_user((short)why
, &infop
->si_code
);
1346 retval
= put_user(status
, &infop
->si_status
);
1348 if (!retval
&& infop
)
1349 retval
= put_user(pid
, &infop
->si_pid
);
1350 if (!retval
&& infop
)
1351 retval
= put_user(uid
, &infop
->si_uid
);
1356 write_lock_irq(&tasklist_lock
);
1357 /* We dropped tasklist, ptracer could die and untrace */
1360 * If this is not a sub-thread, notify the parent.
1361 * If parent wants a zombie, don't release it now.
1363 if (thread_group_leader(p
) &&
1364 !do_notify_parent(p
, p
->exit_signal
)) {
1365 p
->exit_state
= EXIT_ZOMBIE
;
1368 write_unlock_irq(&tasklist_lock
);
1376 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1379 if (task_is_stopped_or_traced(p
) &&
1380 !(p
->jobctl
& JOBCTL_LISTENING
))
1381 return &p
->exit_code
;
1383 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1384 return &p
->signal
->group_exit_code
;
1390 * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
1392 * @ptrace: is the wait for ptrace
1393 * @p: task to wait for
1395 * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
1398 * read_lock(&tasklist_lock), which is released if return value is
1399 * non-zero. Also, grabs and releases @p->sighand->siglock.
1402 * 0 if wait condition didn't exist and search for other wait conditions
1403 * should continue. Non-zero return, -errno on failure and @p's pid on
1404 * success, implies that tasklist_lock is released and wait condition
1405 * search should terminate.
1407 static int wait_task_stopped(struct wait_opts
*wo
,
1408 int ptrace
, struct task_struct
*p
)
1410 struct siginfo __user
*infop
;
1411 int retval
, exit_code
, *p_code
, why
;
1412 uid_t uid
= 0; /* unneeded, required by compiler */
1416 * Traditionally we see ptrace'd stopped tasks regardless of options.
1418 if (!ptrace
&& !(wo
->wo_flags
& WUNTRACED
))
1421 if (!task_stopped_code(p
, ptrace
))
1425 spin_lock_irq(&p
->sighand
->siglock
);
1427 p_code
= task_stopped_code(p
, ptrace
);
1428 if (unlikely(!p_code
))
1431 exit_code
= *p_code
;
1435 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1438 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1440 spin_unlock_irq(&p
->sighand
->siglock
);
1445 * Now we are pretty sure this task is interesting.
1446 * Make sure it doesn't get reaped out from under us while we
1447 * give up the lock and then examine it below. We don't want to
1448 * keep holding onto the tasklist_lock while we call getrusage and
1449 * possibly take page faults for user memory.
1452 pid
= task_pid_vnr(p
);
1453 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1454 read_unlock(&tasklist_lock
);
1456 if (unlikely(wo
->wo_flags
& WNOWAIT
))
1457 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, exit_code
);
1459 retval
= wo
->wo_rusage
1460 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1461 if (!retval
&& wo
->wo_stat
)
1462 retval
= put_user((exit_code
<< 8) | 0x7f, wo
->wo_stat
);
1464 infop
= wo
->wo_info
;
1465 if (!retval
&& infop
)
1466 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1467 if (!retval
&& infop
)
1468 retval
= put_user(0, &infop
->si_errno
);
1469 if (!retval
&& infop
)
1470 retval
= put_user((short)why
, &infop
->si_code
);
1471 if (!retval
&& infop
)
1472 retval
= put_user(exit_code
, &infop
->si_status
);
1473 if (!retval
&& infop
)
1474 retval
= put_user(pid
, &infop
->si_pid
);
1475 if (!retval
&& infop
)
1476 retval
= put_user(uid
, &infop
->si_uid
);
1486 * Handle do_wait work for one task in a live, non-stopped state.
1487 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1488 * the lock and this task is uninteresting. If we return nonzero, we have
1489 * released the lock and the system call should return.
1491 static int wait_task_continued(struct wait_opts
*wo
, struct task_struct
*p
)
1497 if (!unlikely(wo
->wo_flags
& WCONTINUED
))
1500 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1503 spin_lock_irq(&p
->sighand
->siglock
);
1504 /* Re-check with the lock held. */
1505 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1506 spin_unlock_irq(&p
->sighand
->siglock
);
1509 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1510 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1511 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1512 spin_unlock_irq(&p
->sighand
->siglock
);
1514 pid
= task_pid_vnr(p
);
1516 read_unlock(&tasklist_lock
);
1519 retval
= wo
->wo_rusage
1520 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1522 if (!retval
&& wo
->wo_stat
)
1523 retval
= put_user(0xffff, wo
->wo_stat
);
1527 retval
= wait_noreap_copyout(wo
, p
, pid
, uid
,
1528 CLD_CONTINUED
, SIGCONT
);
1529 BUG_ON(retval
== 0);
1536 * Consider @p for a wait by @parent.
1538 * -ECHILD should be in ->notask_error before the first call.
1539 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1540 * Returns zero if the search for a child should continue;
1541 * then ->notask_error is 0 if @p is an eligible child,
1542 * or another error from security_task_wait(), or still -ECHILD.
1544 static int wait_consider_task(struct wait_opts
*wo
, int ptrace
,
1545 struct task_struct
*p
)
1547 int ret
= eligible_child(wo
, p
);
1551 ret
= security_task_wait(p
);
1552 if (unlikely(ret
< 0)) {
1554 * If we have not yet seen any eligible child,
1555 * then let this error code replace -ECHILD.
1556 * A permission error will give the user a clue
1557 * to look for security policy problems, rather
1558 * than for mysterious wait bugs.
1560 if (wo
->notask_error
)
1561 wo
->notask_error
= ret
;
1565 /* dead body doesn't have much to contribute */
1566 if (unlikely(p
->exit_state
== EXIT_DEAD
)) {
1568 * But do not ignore this task until the tracer does
1569 * wait_task_zombie()->do_notify_parent().
1571 if (likely(!ptrace
) && unlikely(ptrace_reparented(p
)))
1572 wo
->notask_error
= 0;
1577 if (p
->exit_state
== EXIT_ZOMBIE
) {
1579 * A zombie ptracee is only visible to its ptracer.
1580 * Notification and reaping will be cascaded to the real
1581 * parent when the ptracer detaches.
1583 if (likely(!ptrace
) && unlikely(p
->ptrace
)) {
1584 /* it will become visible, clear notask_error */
1585 wo
->notask_error
= 0;
1589 /* we don't reap group leaders with subthreads */
1590 if (!delay_group_leader(p
))
1591 return wait_task_zombie(wo
, p
);
1594 * Allow access to stopped/continued state via zombie by
1595 * falling through. Clearing of notask_error is complex.
1599 * If WEXITED is set, notask_error should naturally be
1600 * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
1601 * so, if there are live subthreads, there are events to
1602 * wait for. If all subthreads are dead, it's still safe
1603 * to clear - this function will be called again in finite
1604 * amount time once all the subthreads are released and
1605 * will then return without clearing.
1609 * Stopped state is per-task and thus can't change once the
1610 * target task dies. Only continued and exited can happen.
1611 * Clear notask_error if WCONTINUED | WEXITED.
1613 if (likely(!ptrace
) || (wo
->wo_flags
& (WCONTINUED
| WEXITED
)))
1614 wo
->notask_error
= 0;
1617 * If @p is ptraced by a task in its real parent's group,
1618 * hide group stop/continued state when looking at @p as
1619 * the real parent; otherwise, a single stop can be
1620 * reported twice as group and ptrace stops.
1622 * If a ptracer wants to distinguish the two events for its
1623 * own children, it should create a separate process which
1624 * takes the role of real parent.
1626 if (likely(!ptrace
) && p
->ptrace
&& !ptrace_reparented(p
))
1630 * @p is alive and it's gonna stop, continue or exit, so
1631 * there always is something to wait for.
1633 wo
->notask_error
= 0;
1637 * Wait for stopped. Depending on @ptrace, different stopped state
1638 * is used and the two don't interact with each other.
1640 ret
= wait_task_stopped(wo
, ptrace
, p
);
1645 * Wait for continued. There's only one continued state and the
1646 * ptracer can consume it which can confuse the real parent. Don't
1647 * use WCONTINUED from ptracer. You don't need or want it.
1649 return wait_task_continued(wo
, p
);
1653 * Do the work of do_wait() for one thread in the group, @tsk.
1655 * -ECHILD should be in ->notask_error before the first call.
1656 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1657 * Returns zero if the search for a child should continue; then
1658 * ->notask_error is 0 if there were any eligible children,
1659 * or another error from security_task_wait(), or still -ECHILD.
1661 static int do_wait_thread(struct wait_opts
*wo
, struct task_struct
*tsk
)
1663 struct task_struct
*p
;
1665 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1666 int ret
= wait_consider_task(wo
, 0, p
);
1674 static int ptrace_do_wait(struct wait_opts
*wo
, struct task_struct
*tsk
)
1676 struct task_struct
*p
;
1678 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1679 int ret
= wait_consider_task(wo
, 1, p
);
1687 static int child_wait_callback(wait_queue_t
*wait
, unsigned mode
,
1688 int sync
, void *key
)
1690 struct wait_opts
*wo
= container_of(wait
, struct wait_opts
,
1692 struct task_struct
*p
= key
;
1694 if (!eligible_pid(wo
, p
))
1697 if ((wo
->wo_flags
& __WNOTHREAD
) && wait
->private != p
->parent
)
1700 return default_wake_function(wait
, mode
, sync
, key
);
1703 void __wake_up_parent(struct task_struct
*p
, struct task_struct
*parent
)
1705 __wake_up_sync_key(&parent
->signal
->wait_chldexit
,
1706 TASK_INTERRUPTIBLE
, 1, p
);
1709 static long do_wait(struct wait_opts
*wo
)
1711 struct task_struct
*tsk
;
1714 trace_sched_process_wait(wo
->wo_pid
);
1716 init_waitqueue_func_entry(&wo
->child_wait
, child_wait_callback
);
1717 wo
->child_wait
.private = current
;
1718 add_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1721 * If there is nothing that can match our critiera just get out.
1722 * We will clear ->notask_error to zero if we see any child that
1723 * might later match our criteria, even if we are not able to reap
1726 wo
->notask_error
= -ECHILD
;
1727 if ((wo
->wo_type
< PIDTYPE_MAX
) &&
1728 (!wo
->wo_pid
|| hlist_empty(&wo
->wo_pid
->tasks
[wo
->wo_type
])))
1731 set_current_state(TASK_INTERRUPTIBLE
);
1732 read_lock(&tasklist_lock
);
1735 retval
= do_wait_thread(wo
, tsk
);
1739 retval
= ptrace_do_wait(wo
, tsk
);
1743 if (wo
->wo_flags
& __WNOTHREAD
)
1745 } while_each_thread(current
, tsk
);
1746 read_unlock(&tasklist_lock
);
1749 retval
= wo
->notask_error
;
1750 if (!retval
&& !(wo
->wo_flags
& WNOHANG
)) {
1751 retval
= -ERESTARTSYS
;
1752 if (!signal_pending(current
)) {
1758 __set_current_state(TASK_RUNNING
);
1759 remove_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1763 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1764 infop
, int, options
, struct rusage __user
*, ru
)
1766 struct wait_opts wo
;
1767 struct pid
*pid
= NULL
;
1771 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1773 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1786 type
= PIDTYPE_PGID
;
1794 if (type
< PIDTYPE_MAX
)
1795 pid
= find_get_pid(upid
);
1799 wo
.wo_flags
= options
;
1809 * For a WNOHANG return, clear out all the fields
1810 * we would set so the user can easily tell the
1814 ret
= put_user(0, &infop
->si_signo
);
1816 ret
= put_user(0, &infop
->si_errno
);
1818 ret
= put_user(0, &infop
->si_code
);
1820 ret
= put_user(0, &infop
->si_pid
);
1822 ret
= put_user(0, &infop
->si_uid
);
1824 ret
= put_user(0, &infop
->si_status
);
1829 /* avoid REGPARM breakage on x86: */
1830 asmlinkage_protect(5, ret
, which
, upid
, infop
, options
, ru
);
1834 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1835 int, options
, struct rusage __user
*, ru
)
1837 struct wait_opts wo
;
1838 struct pid
*pid
= NULL
;
1842 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1843 __WNOTHREAD
|__WCLONE
|__WALL
))
1848 else if (upid
< 0) {
1849 type
= PIDTYPE_PGID
;
1850 pid
= find_get_pid(-upid
);
1851 } else if (upid
== 0) {
1852 type
= PIDTYPE_PGID
;
1853 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1854 } else /* upid > 0 */ {
1856 pid
= find_get_pid(upid
);
1861 wo
.wo_flags
= options
| WEXITED
;
1863 wo
.wo_stat
= stat_addr
;
1868 /* avoid REGPARM breakage on x86: */
1869 asmlinkage_protect(4, ret
, upid
, stat_addr
, options
, ru
);
1873 #ifdef __ARCH_WANT_SYS_WAITPID
1876 * sys_waitpid() remains for compatibility. waitpid() should be
1877 * implemented by calling sys_wait4() from libc.a.
1879 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1881 return sys_wait4(pid
, stat_addr
, options
, NULL
);
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