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 list_del_rcu(&p
->thread_group
);
80 * This function expects the tasklist_lock write-locked.
82 static void __exit_signal(struct task_struct
*tsk
)
84 struct signal_struct
*sig
= tsk
->signal
;
85 bool group_dead
= thread_group_leader(tsk
);
86 struct sighand_struct
*sighand
;
87 struct tty_struct
*uninitialized_var(tty
);
89 sighand
= rcu_dereference_check(tsk
->sighand
,
90 lockdep_tasklist_lock_is_held());
91 spin_lock(&sighand
->siglock
);
93 posix_cpu_timers_exit(tsk
);
95 posix_cpu_timers_exit_group(tsk
);
100 * This can only happen if the caller is de_thread().
101 * FIXME: this is the temporary hack, we should teach
102 * posix-cpu-timers to handle this case correctly.
104 if (unlikely(has_group_leader_pid(tsk
)))
105 posix_cpu_timers_exit_group(tsk
);
108 * If there is any task waiting for the group exit
111 if (sig
->notify_count
> 0 && !--sig
->notify_count
)
112 wake_up_process(sig
->group_exit_task
);
114 if (tsk
== sig
->curr_target
)
115 sig
->curr_target
= next_thread(tsk
);
117 * Accumulate here the counters for all threads but the
118 * group leader as they die, so they can be added into
119 * the process-wide totals when those are taken.
120 * The group leader stays around as a zombie as long
121 * as there are other threads. When it gets reaped,
122 * the exit.c code will add its counts into these totals.
123 * We won't ever get here for the group leader, since it
124 * will have been the last reference on the signal_struct.
126 sig
->utime
+= tsk
->utime
;
127 sig
->stime
+= tsk
->stime
;
128 sig
->gtime
+= tsk
->gtime
;
129 sig
->min_flt
+= tsk
->min_flt
;
130 sig
->maj_flt
+= tsk
->maj_flt
;
131 sig
->nvcsw
+= tsk
->nvcsw
;
132 sig
->nivcsw
+= tsk
->nivcsw
;
133 sig
->inblock
+= task_io_get_inblock(tsk
);
134 sig
->oublock
+= task_io_get_oublock(tsk
);
135 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
136 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
140 __unhash_process(tsk
, group_dead
);
143 * Do this under ->siglock, we can race with another thread
144 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
146 flush_sigqueue(&tsk
->pending
);
148 spin_unlock(&sighand
->siglock
);
150 __cleanup_sighand(sighand
);
151 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
153 flush_sigqueue(&sig
->shared_pending
);
158 static void delayed_put_task_struct(struct rcu_head
*rhp
)
160 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
162 perf_event_delayed_put(tsk
);
163 trace_sched_process_free(tsk
);
164 put_task_struct(tsk
);
168 void release_task(struct task_struct
* p
)
170 struct task_struct
*leader
;
173 /* don't need to get the RCU readlock here - the process is dead and
174 * can't be modifying its own credentials. But shut RCU-lockdep up */
176 atomic_dec(&__task_cred(p
)->user
->processes
);
181 write_lock_irq(&tasklist_lock
);
182 ptrace_release_task(p
);
186 * If we are the last non-leader member of the thread
187 * group, and the leader is zombie, then notify the
188 * group leader's parent process. (if it wants notification.)
191 leader
= p
->group_leader
;
192 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
194 * If we were the last child thread and the leader has
195 * exited already, and the leader's parent ignores SIGCHLD,
196 * then we are the one who should release the leader.
198 zap_leader
= do_notify_parent(leader
, leader
->exit_signal
);
200 leader
->exit_state
= EXIT_DEAD
;
203 write_unlock_irq(&tasklist_lock
);
205 call_rcu(&p
->rcu
, delayed_put_task_struct
);
208 if (unlikely(zap_leader
))
213 * This checks not only the pgrp, but falls back on the pid if no
214 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
217 * The caller must hold rcu lock or the tasklist lock.
219 struct pid
*session_of_pgrp(struct pid
*pgrp
)
221 struct task_struct
*p
;
222 struct pid
*sid
= NULL
;
224 p
= pid_task(pgrp
, PIDTYPE_PGID
);
226 p
= pid_task(pgrp
, PIDTYPE_PID
);
228 sid
= task_session(p
);
234 * Determine if a process group is "orphaned", according to the POSIX
235 * definition in 2.2.2.52. Orphaned process groups are not to be affected
236 * by terminal-generated stop signals. Newly orphaned process groups are
237 * to receive a SIGHUP and a SIGCONT.
239 * "I ask you, have you ever known what it is to be an orphan?"
241 static int will_become_orphaned_pgrp(struct pid
*pgrp
, struct task_struct
*ignored_task
)
243 struct task_struct
*p
;
245 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
246 if ((p
== ignored_task
) ||
247 (p
->exit_state
&& thread_group_empty(p
)) ||
248 is_global_init(p
->real_parent
))
251 if (task_pgrp(p
->real_parent
) != pgrp
&&
252 task_session(p
->real_parent
) == task_session(p
))
254 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
259 int is_current_pgrp_orphaned(void)
263 read_lock(&tasklist_lock
);
264 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
265 read_unlock(&tasklist_lock
);
270 static bool has_stopped_jobs(struct pid
*pgrp
)
272 struct task_struct
*p
;
274 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
275 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
277 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
283 * Check to see if any process groups have become orphaned as
284 * a result of our exiting, and if they have any stopped jobs,
285 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
288 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
290 struct pid
*pgrp
= task_pgrp(tsk
);
291 struct task_struct
*ignored_task
= tsk
;
294 /* exit: our father is in a different pgrp than
295 * we are and we were the only connection outside.
297 parent
= tsk
->real_parent
;
299 /* reparent: our child is in a different pgrp than
300 * we are, and it was the only connection outside.
304 if (task_pgrp(parent
) != pgrp
&&
305 task_session(parent
) == task_session(tsk
) &&
306 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
307 has_stopped_jobs(pgrp
)) {
308 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
309 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
314 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
316 * If a kernel thread is launched as a result of a system call, or if
317 * it ever exits, it should generally reparent itself to kthreadd so it
318 * isn't in the way of other processes and is correctly cleaned up on exit.
320 * The various task state such as scheduling policy and priority may have
321 * been inherited from a user process, so we reset them to sane values here.
323 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
325 static void reparent_to_kthreadd(void)
327 write_lock_irq(&tasklist_lock
);
329 ptrace_unlink(current
);
330 /* Reparent to init */
331 current
->real_parent
= current
->parent
= kthreadd_task
;
332 list_move_tail(¤t
->sibling
, ¤t
->real_parent
->children
);
334 /* Set the exit signal to SIGCHLD so we signal init on exit */
335 current
->exit_signal
= SIGCHLD
;
337 if (task_nice(current
) < 0)
338 set_user_nice(current
, 0);
342 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
343 sizeof(current
->signal
->rlim
));
345 atomic_inc(&init_cred
.usage
);
346 commit_creds(&init_cred
);
347 write_unlock_irq(&tasklist_lock
);
350 void __set_special_pids(struct pid
*pid
)
352 struct task_struct
*curr
= current
->group_leader
;
354 if (task_session(curr
) != pid
)
355 change_pid(curr
, PIDTYPE_SID
, pid
);
357 if (task_pgrp(curr
) != pid
)
358 change_pid(curr
, PIDTYPE_PGID
, pid
);
361 static void set_special_pids(struct pid
*pid
)
363 write_lock_irq(&tasklist_lock
);
364 __set_special_pids(pid
);
365 write_unlock_irq(&tasklist_lock
);
369 * Let kernel threads use this to say that they allow a certain signal.
370 * Must not be used if kthread was cloned with CLONE_SIGHAND.
372 int allow_signal(int sig
)
374 if (!valid_signal(sig
) || sig
< 1)
377 spin_lock_irq(¤t
->sighand
->siglock
);
378 /* This is only needed for daemonize()'ed kthreads */
379 sigdelset(¤t
->blocked
, sig
);
381 * Kernel threads handle their own signals. Let the signal code
382 * know it'll be handled, so that they don't get converted to
383 * SIGKILL or just silently dropped.
385 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
387 spin_unlock_irq(¤t
->sighand
->siglock
);
391 EXPORT_SYMBOL(allow_signal
);
393 int disallow_signal(int sig
)
395 if (!valid_signal(sig
) || sig
< 1)
398 spin_lock_irq(¤t
->sighand
->siglock
);
399 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= SIG_IGN
;
401 spin_unlock_irq(¤t
->sighand
->siglock
);
405 EXPORT_SYMBOL(disallow_signal
);
408 * Put all the gunge required to become a kernel thread without
409 * attached user resources in one place where it belongs.
412 void daemonize(const char *name
, ...)
417 va_start(args
, name
);
418 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
422 * If we were started as result of loading a module, close all of the
423 * user space pages. We don't need them, and if we didn't close them
424 * they would be locked into memory.
428 * We don't want to have TIF_FREEZE set if the system-wide hibernation
429 * or suspend transition begins right now.
431 current
->flags
|= (PF_NOFREEZE
| PF_KTHREAD
);
433 if (current
->nsproxy
!= &init_nsproxy
) {
434 get_nsproxy(&init_nsproxy
);
435 switch_task_namespaces(current
, &init_nsproxy
);
437 set_special_pids(&init_struct_pid
);
438 proc_clear_tty(current
);
440 /* Block and flush all signals */
441 sigfillset(&blocked
);
442 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
443 flush_signals(current
);
445 /* Become as one with the init task */
447 daemonize_fs_struct();
449 current
->files
= init_task
.files
;
450 atomic_inc(¤t
->files
->count
);
452 reparent_to_kthreadd();
455 EXPORT_SYMBOL(daemonize
);
457 static void close_files(struct files_struct
* files
)
465 * It is safe to dereference the fd table without RCU or
466 * ->file_lock because this is the last reference to the
467 * files structure. But use RCU to shut RCU-lockdep up.
470 fdt
= files_fdtable(files
);
475 if (i
>= fdt
->max_fds
)
477 set
= fdt
->open_fds
->fds_bits
[j
++];
480 struct file
* file
= xchg(&fdt
->fd
[i
], NULL
);
482 filp_close(file
, files
);
492 struct files_struct
*get_files_struct(struct task_struct
*task
)
494 struct files_struct
*files
;
499 atomic_inc(&files
->count
);
505 void put_files_struct(struct files_struct
*files
)
509 if (atomic_dec_and_test(&files
->count
)) {
512 * Free the fd and fdset arrays if we expanded them.
513 * If the fdtable was embedded, pass files for freeing
514 * at the end of the RCU grace period. Otherwise,
515 * you can free files immediately.
518 fdt
= files_fdtable(files
);
519 if (fdt
!= &files
->fdtab
)
520 kmem_cache_free(files_cachep
, files
);
526 void reset_files_struct(struct files_struct
*files
)
528 struct task_struct
*tsk
= current
;
529 struct files_struct
*old
;
535 put_files_struct(old
);
538 void exit_files(struct task_struct
*tsk
)
540 struct files_struct
* files
= tsk
->files
;
546 put_files_struct(files
);
550 #ifdef CONFIG_MM_OWNER
552 * A task is exiting. If it owned this mm, find a new owner for the mm.
554 void mm_update_next_owner(struct mm_struct
*mm
)
556 struct task_struct
*c
, *g
, *p
= current
;
560 * If the exiting or execing task is not the owner, it's
561 * someone else's problem.
566 * The current owner is exiting/execing and there are no other
567 * candidates. Do not leave the mm pointing to a possibly
568 * freed task structure.
570 if (atomic_read(&mm
->mm_users
) <= 1) {
575 read_lock(&tasklist_lock
);
577 * Search in the children
579 list_for_each_entry(c
, &p
->children
, sibling
) {
581 goto assign_new_owner
;
585 * Search in the siblings
587 list_for_each_entry(c
, &p
->real_parent
->children
, sibling
) {
589 goto assign_new_owner
;
593 * Search through everything else. We should not get
596 do_each_thread(g
, c
) {
598 goto assign_new_owner
;
599 } while_each_thread(g
, c
);
601 read_unlock(&tasklist_lock
);
603 * We found no owner yet mm_users > 1: this implies that we are
604 * most likely racing with swapoff (try_to_unuse()) or /proc or
605 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
614 * The task_lock protects c->mm from changing.
615 * We always want mm->owner->mm == mm
619 * Delay read_unlock() till we have the task_lock()
620 * to ensure that c does not slip away underneath us
622 read_unlock(&tasklist_lock
);
632 #endif /* CONFIG_MM_OWNER */
635 * Turn us into a lazy TLB process if we
638 static void exit_mm(struct task_struct
* tsk
)
640 struct mm_struct
*mm
= tsk
->mm
;
641 struct core_state
*core_state
;
647 * Serialize with any possible pending coredump.
648 * We must hold mmap_sem around checking core_state
649 * and clearing tsk->mm. The core-inducing thread
650 * will increment ->nr_threads for each thread in the
651 * group with ->mm != NULL.
653 down_read(&mm
->mmap_sem
);
654 core_state
= mm
->core_state
;
656 struct core_thread self
;
657 up_read(&mm
->mmap_sem
);
660 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
662 * Implies mb(), the result of xchg() must be visible
663 * to core_state->dumper.
665 if (atomic_dec_and_test(&core_state
->nr_threads
))
666 complete(&core_state
->startup
);
669 set_task_state(tsk
, TASK_UNINTERRUPTIBLE
);
670 if (!self
.task
) /* see coredump_finish() */
674 __set_task_state(tsk
, TASK_RUNNING
);
675 down_read(&mm
->mmap_sem
);
677 atomic_inc(&mm
->mm_count
);
678 BUG_ON(mm
!= tsk
->active_mm
);
679 /* more a memory barrier than a real lock */
682 up_read(&mm
->mmap_sem
);
683 enter_lazy_tlb(mm
, current
);
685 mm_update_next_owner(mm
);
690 * When we die, we re-parent all our children.
691 * Try to give them to another thread in our thread
692 * group, and if no such member exists, give it to
693 * the child reaper process (ie "init") in our pid
696 static struct task_struct
*find_new_reaper(struct task_struct
*father
)
697 __releases(&tasklist_lock
)
698 __acquires(&tasklist_lock
)
700 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
701 struct task_struct
*thread
;
704 while_each_thread(father
, thread
) {
705 if (thread
->flags
& PF_EXITING
)
707 if (unlikely(pid_ns
->child_reaper
== father
))
708 pid_ns
->child_reaper
= thread
;
712 if (unlikely(pid_ns
->child_reaper
== father
)) {
713 write_unlock_irq(&tasklist_lock
);
714 if (unlikely(pid_ns
== &init_pid_ns
))
715 panic("Attempted to kill init!");
717 zap_pid_ns_processes(pid_ns
);
718 write_lock_irq(&tasklist_lock
);
720 * We can not clear ->child_reaper or leave it alone.
721 * There may by stealth EXIT_DEAD tasks on ->children,
722 * forget_original_parent() must move them somewhere.
724 pid_ns
->child_reaper
= init_pid_ns
.child_reaper
;
727 return pid_ns
->child_reaper
;
731 * Any that need to be release_task'd are put on the @dead list.
733 static void reparent_leader(struct task_struct
*father
, struct task_struct
*p
,
734 struct list_head
*dead
)
736 list_move_tail(&p
->sibling
, &p
->real_parent
->children
);
738 if (p
->exit_state
== EXIT_DEAD
)
741 * If this is a threaded reparent there is no need to
742 * notify anyone anything has happened.
744 if (same_thread_group(p
->real_parent
, father
))
747 /* We don't want people slaying init. */
748 p
->exit_signal
= SIGCHLD
;
750 /* If it has exited notify the new parent about this child's death. */
752 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
753 if (do_notify_parent(p
, p
->exit_signal
)) {
754 p
->exit_state
= EXIT_DEAD
;
755 list_move_tail(&p
->sibling
, dead
);
759 kill_orphaned_pgrp(p
, father
);
762 static void forget_original_parent(struct task_struct
*father
)
764 struct task_struct
*p
, *n
, *reaper
;
765 LIST_HEAD(dead_children
);
767 write_lock_irq(&tasklist_lock
);
769 * Note that exit_ptrace() and find_new_reaper() might
770 * drop tasklist_lock and reacquire it.
773 reaper
= find_new_reaper(father
);
775 list_for_each_entry_safe(p
, n
, &father
->children
, sibling
) {
776 struct task_struct
*t
= p
;
778 t
->real_parent
= reaper
;
779 if (t
->parent
== father
) {
781 t
->parent
= t
->real_parent
;
783 if (t
->pdeath_signal
)
784 group_send_sig_info(t
->pdeath_signal
,
786 } while_each_thread(p
, t
);
787 reparent_leader(father
, p
, &dead_children
);
789 write_unlock_irq(&tasklist_lock
);
791 BUG_ON(!list_empty(&father
->children
));
793 list_for_each_entry_safe(p
, n
, &dead_children
, sibling
) {
794 list_del_init(&p
->sibling
);
800 * Send signals to all our closest relatives so that they know
801 * to properly mourn us..
803 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
808 * This does two things:
810 * A. Make init inherit all the child processes
811 * B. Check to see if any process groups have become orphaned
812 * as a result of our exiting, and if they have any stopped
813 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
815 forget_original_parent(tsk
);
816 exit_task_namespaces(tsk
);
818 write_lock_irq(&tasklist_lock
);
820 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
822 /* Let father know we died
824 * Thread signals are configurable, but you aren't going to use
825 * that to send signals to arbitrary processes.
826 * That stops right now.
828 * If the parent exec id doesn't match the exec id we saved
829 * when we started then we know the parent has changed security
832 * If our self_exec id doesn't match our parent_exec_id then
833 * we have changed execution domain as these two values started
834 * the same after a fork.
836 if (thread_group_leader(tsk
) && tsk
->exit_signal
!= SIGCHLD
&&
837 (tsk
->parent_exec_id
!= tsk
->real_parent
->self_exec_id
||
838 tsk
->self_exec_id
!= tsk
->parent_exec_id
))
839 tsk
->exit_signal
= SIGCHLD
;
841 if (unlikely(tsk
->ptrace
)) {
842 int sig
= thread_group_leader(tsk
) &&
843 thread_group_empty(tsk
) &&
844 !ptrace_reparented(tsk
) ?
845 tsk
->exit_signal
: SIGCHLD
;
846 autoreap
= do_notify_parent(tsk
, sig
);
847 } else if (thread_group_leader(tsk
)) {
848 autoreap
= thread_group_empty(tsk
) &&
849 do_notify_parent(tsk
, tsk
->exit_signal
);
854 tsk
->exit_state
= autoreap
? 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 /* If the process is dead, release it - nobody will wait for it */
866 #ifdef CONFIG_DEBUG_STACK_USAGE
867 static void check_stack_usage(void)
869 static DEFINE_SPINLOCK(low_water_lock
);
870 static int lowest_to_date
= THREAD_SIZE
;
873 free
= stack_not_used(current
);
875 if (free
>= lowest_to_date
)
878 spin_lock(&low_water_lock
);
879 if (free
< lowest_to_date
) {
880 printk(KERN_WARNING
"%s used greatest stack depth: %lu bytes "
882 current
->comm
, free
);
883 lowest_to_date
= free
;
885 spin_unlock(&low_water_lock
);
888 static inline void check_stack_usage(void) {}
891 void do_exit(long code
)
893 struct task_struct
*tsk
= current
;
896 profile_task_exit(tsk
);
898 WARN_ON(blk_needs_flush_plug(tsk
));
900 if (unlikely(in_interrupt()))
901 panic("Aiee, killing interrupt handler!");
902 if (unlikely(!tsk
->pid
))
903 panic("Attempted to kill the idle task!");
906 * If do_exit is called because this processes oopsed, it's possible
907 * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
908 * continuing. Amongst other possible reasons, this is to prevent
909 * mm_release()->clear_child_tid() from writing to a user-controlled
914 ptrace_event(PTRACE_EVENT_EXIT
, code
);
916 validate_creds_for_do_exit(tsk
);
919 * We're taking recursive faults here in do_exit. Safest is to just
920 * leave this task alone and wait for reboot.
922 if (unlikely(tsk
->flags
& PF_EXITING
)) {
924 "Fixing recursive fault but reboot is needed!\n");
926 * We can do this unlocked here. The futex code uses
927 * this flag just to verify whether the pi state
928 * cleanup has been done or not. In the worst case it
929 * loops once more. We pretend that the cleanup was
930 * done as there is no way to return. Either the
931 * OWNER_DIED bit is set by now or we push the blocked
932 * task into the wait for ever nirwana as well.
934 tsk
->flags
|= PF_EXITPIDONE
;
935 set_current_state(TASK_UNINTERRUPTIBLE
);
941 exit_signals(tsk
); /* sets PF_EXITING */
943 * tsk->flags are checked in the futex code to protect against
944 * an exiting task cleaning up the robust pi futexes.
947 raw_spin_unlock_wait(&tsk
->pi_lock
);
949 if (unlikely(in_atomic()))
950 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
951 current
->comm
, task_pid_nr(current
),
954 acct_update_integrals(tsk
);
955 /* sync mm's RSS info before statistics gathering */
957 sync_mm_rss(tsk
, tsk
->mm
);
958 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
960 hrtimer_cancel(&tsk
->signal
->real_timer
);
961 exit_itimers(tsk
->signal
);
963 setmax_mm_hiwater_rss(&tsk
->signal
->maxrss
, tsk
->mm
);
965 acct_collect(code
, group_dead
);
970 tsk
->exit_code
= code
;
971 taskstats_exit(tsk
, group_dead
);
977 trace_sched_process_exit(tsk
);
987 * Flush inherited counters to the parent - before the parent
988 * gets woken up by child-exit notifications.
990 * because of cgroup mode, must be called before cgroup_exit()
992 perf_event_exit_task(tsk
);
997 disassociate_ctty(1);
999 module_put(task_thread_info(tsk
)->exec_domain
->module
);
1001 proc_exit_connector(tsk
);
1004 * FIXME: do that only when needed, using sched_exit tracepoint
1006 ptrace_put_breakpoints(tsk
);
1008 exit_notify(tsk
, group_dead
);
1011 mpol_put(tsk
->mempolicy
);
1012 tsk
->mempolicy
= NULL
;
1016 if (unlikely(current
->pi_state_cache
))
1017 kfree(current
->pi_state_cache
);
1020 * Make sure we are holding no locks:
1022 debug_check_no_locks_held(tsk
);
1024 * We can do this unlocked here. The futex code uses this flag
1025 * just to verify whether the pi state cleanup has been done
1026 * or not. In the worst case it loops once more.
1028 tsk
->flags
|= PF_EXITPIDONE
;
1030 if (tsk
->io_context
)
1031 exit_io_context(tsk
);
1033 if (tsk
->splice_pipe
)
1034 __free_pipe_info(tsk
->splice_pipe
);
1036 validate_creds_for_do_exit(tsk
);
1039 if (tsk
->nr_dirtied
)
1040 __this_cpu_add(dirty_throttle_leaks
, tsk
->nr_dirtied
);
1044 * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
1045 * when the following two conditions become true.
1046 * - There is race condition of mmap_sem (It is acquired by
1048 * - SMI occurs before setting TASK_RUNINNG.
1049 * (or hypervisor of virtual machine switches to other guest)
1050 * As a result, we may become TASK_RUNNING after becoming TASK_DEAD
1052 * To avoid it, we have to wait for releasing tsk->pi_lock which
1053 * is held by try_to_wake_up()
1056 raw_spin_unlock_wait(&tsk
->pi_lock
);
1058 /* causes final put_task_struct in finish_task_switch(). */
1059 tsk
->state
= TASK_DEAD
;
1060 tsk
->flags
|= PF_NOFREEZE
; /* tell freezer to ignore us */
1063 /* Avoid "noreturn function does return". */
1065 cpu_relax(); /* For when BUG is null */
1068 EXPORT_SYMBOL_GPL(do_exit
);
1070 void complete_and_exit(struct completion
*comp
, long code
)
1078 EXPORT_SYMBOL(complete_and_exit
);
1080 SYSCALL_DEFINE1(exit
, int, error_code
)
1082 do_exit((error_code
&0xff)<<8);
1086 * Take down every thread in the group. This is called by fatal signals
1087 * as well as by sys_exit_group (below).
1090 do_group_exit(int exit_code
)
1092 struct signal_struct
*sig
= current
->signal
;
1094 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
1096 if (signal_group_exit(sig
))
1097 exit_code
= sig
->group_exit_code
;
1098 else if (!thread_group_empty(current
)) {
1099 struct sighand_struct
*const sighand
= current
->sighand
;
1100 spin_lock_irq(&sighand
->siglock
);
1101 if (signal_group_exit(sig
))
1102 /* Another thread got here before we took the lock. */
1103 exit_code
= sig
->group_exit_code
;
1105 sig
->group_exit_code
= exit_code
;
1106 sig
->flags
= SIGNAL_GROUP_EXIT
;
1107 zap_other_threads(current
);
1109 spin_unlock_irq(&sighand
->siglock
);
1117 * this kills every thread in the thread group. Note that any externally
1118 * wait4()-ing process will get the correct exit code - even if this
1119 * thread is not the thread group leader.
1121 SYSCALL_DEFINE1(exit_group
, int, error_code
)
1123 do_group_exit((error_code
& 0xff) << 8);
1129 enum pid_type wo_type
;
1133 struct siginfo __user
*wo_info
;
1134 int __user
*wo_stat
;
1135 struct rusage __user
*wo_rusage
;
1137 wait_queue_t child_wait
;
1142 struct pid
*task_pid_type(struct task_struct
*task
, enum pid_type type
)
1144 if (type
!= PIDTYPE_PID
)
1145 task
= task
->group_leader
;
1146 return task
->pids
[type
].pid
;
1149 static int eligible_pid(struct wait_opts
*wo
, struct task_struct
*p
)
1151 return wo
->wo_type
== PIDTYPE_MAX
||
1152 task_pid_type(p
, wo
->wo_type
) == wo
->wo_pid
;
1155 static int eligible_child(struct wait_opts
*wo
, struct task_struct
*p
)
1157 if (!eligible_pid(wo
, p
))
1159 /* Wait for all children (clone and not) if __WALL is set;
1160 * otherwise, wait for clone children *only* if __WCLONE is
1161 * set; otherwise, wait for non-clone children *only*. (Note:
1162 * A "clone" child here is one that reports to its parent
1163 * using a signal other than SIGCHLD.) */
1164 if (((p
->exit_signal
!= SIGCHLD
) ^ !!(wo
->wo_flags
& __WCLONE
))
1165 && !(wo
->wo_flags
& __WALL
))
1171 static int wait_noreap_copyout(struct wait_opts
*wo
, struct task_struct
*p
,
1172 pid_t pid
, uid_t uid
, int why
, int status
)
1174 struct siginfo __user
*infop
;
1175 int retval
= wo
->wo_rusage
1176 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1179 infop
= wo
->wo_info
;
1182 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1184 retval
= put_user(0, &infop
->si_errno
);
1186 retval
= put_user((short)why
, &infop
->si_code
);
1188 retval
= put_user(pid
, &infop
->si_pid
);
1190 retval
= put_user(uid
, &infop
->si_uid
);
1192 retval
= put_user(status
, &infop
->si_status
);
1200 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1201 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1202 * the lock and this task is uninteresting. If we return nonzero, we have
1203 * released the lock and the system call should return.
1205 static int wait_task_zombie(struct wait_opts
*wo
, struct task_struct
*p
)
1207 unsigned long state
;
1208 int retval
, status
, traced
;
1209 pid_t pid
= task_pid_vnr(p
);
1210 uid_t uid
= __task_cred(p
)->uid
;
1211 struct siginfo __user
*infop
;
1213 if (!likely(wo
->wo_flags
& WEXITED
))
1216 if (unlikely(wo
->wo_flags
& WNOWAIT
)) {
1217 int exit_code
= p
->exit_code
;
1221 read_unlock(&tasklist_lock
);
1222 if ((exit_code
& 0x7f) == 0) {
1224 status
= exit_code
>> 8;
1226 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1227 status
= exit_code
& 0x7f;
1229 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, status
);
1233 * Try to move the task's state to DEAD
1234 * only one thread is allowed to do this:
1236 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1237 if (state
!= EXIT_ZOMBIE
) {
1238 BUG_ON(state
!= EXIT_DEAD
);
1242 traced
= ptrace_reparented(p
);
1244 * It can be ptraced but not reparented, check
1245 * thread_group_leader() to filter out sub-threads.
1247 if (likely(!traced
) && thread_group_leader(p
)) {
1248 struct signal_struct
*psig
;
1249 struct signal_struct
*sig
;
1250 unsigned long maxrss
;
1251 cputime_t tgutime
, tgstime
;
1254 * The resource counters for the group leader are in its
1255 * own task_struct. Those for dead threads in the group
1256 * are in its signal_struct, as are those for the child
1257 * processes it has previously reaped. All these
1258 * accumulate in the parent's signal_struct c* fields.
1260 * We don't bother to take a lock here to protect these
1261 * p->signal fields, because they are only touched by
1262 * __exit_signal, which runs with tasklist_lock
1263 * write-locked anyway, and so is excluded here. We do
1264 * need to protect the access to parent->signal fields,
1265 * as other threads in the parent group can be right
1266 * here reaping other children at the same time.
1268 * We use thread_group_times() to get times for the thread
1269 * group, which consolidates times for all threads in the
1270 * group including the group leader.
1272 thread_group_times(p
, &tgutime
, &tgstime
);
1273 spin_lock_irq(&p
->real_parent
->sighand
->siglock
);
1274 psig
= p
->real_parent
->signal
;
1276 psig
->cutime
+= tgutime
+ sig
->cutime
;
1277 psig
->cstime
+= tgstime
+ sig
->cstime
;
1278 psig
->cgtime
+= p
->gtime
+ sig
->gtime
+ sig
->cgtime
;
1280 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1282 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1284 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1286 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1288 task_io_get_inblock(p
) +
1289 sig
->inblock
+ sig
->cinblock
;
1291 task_io_get_oublock(p
) +
1292 sig
->oublock
+ sig
->coublock
;
1293 maxrss
= max(sig
->maxrss
, sig
->cmaxrss
);
1294 if (psig
->cmaxrss
< maxrss
)
1295 psig
->cmaxrss
= maxrss
;
1296 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1297 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1298 spin_unlock_irq(&p
->real_parent
->sighand
->siglock
);
1302 * Now we are sure this task is interesting, and no other
1303 * thread can reap it because we set its state to EXIT_DEAD.
1305 read_unlock(&tasklist_lock
);
1307 retval
= wo
->wo_rusage
1308 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1309 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1310 ? p
->signal
->group_exit_code
: p
->exit_code
;
1311 if (!retval
&& wo
->wo_stat
)
1312 retval
= put_user(status
, wo
->wo_stat
);
1314 infop
= wo
->wo_info
;
1315 if (!retval
&& infop
)
1316 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1317 if (!retval
&& infop
)
1318 retval
= put_user(0, &infop
->si_errno
);
1319 if (!retval
&& infop
) {
1322 if ((status
& 0x7f) == 0) {
1326 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1329 retval
= put_user((short)why
, &infop
->si_code
);
1331 retval
= put_user(status
, &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
);
1341 write_lock_irq(&tasklist_lock
);
1342 /* We dropped tasklist, ptracer could die and untrace */
1345 * If this is not a sub-thread, notify the parent.
1346 * If parent wants a zombie, don't release it now.
1348 if (thread_group_leader(p
) &&
1349 !do_notify_parent(p
, p
->exit_signal
)) {
1350 p
->exit_state
= EXIT_ZOMBIE
;
1353 write_unlock_irq(&tasklist_lock
);
1361 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1364 if (task_is_stopped_or_traced(p
) &&
1365 !(p
->jobctl
& JOBCTL_LISTENING
))
1366 return &p
->exit_code
;
1368 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1369 return &p
->signal
->group_exit_code
;
1375 * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
1377 * @ptrace: is the wait for ptrace
1378 * @p: task to wait for
1380 * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
1383 * read_lock(&tasklist_lock), which is released if return value is
1384 * non-zero. Also, grabs and releases @p->sighand->siglock.
1387 * 0 if wait condition didn't exist and search for other wait conditions
1388 * should continue. Non-zero return, -errno on failure and @p's pid on
1389 * success, implies that tasklist_lock is released and wait condition
1390 * search should terminate.
1392 static int wait_task_stopped(struct wait_opts
*wo
,
1393 int ptrace
, struct task_struct
*p
)
1395 struct siginfo __user
*infop
;
1396 int retval
, exit_code
, *p_code
, why
;
1397 uid_t uid
= 0; /* unneeded, required by compiler */
1401 * Traditionally we see ptrace'd stopped tasks regardless of options.
1403 if (!ptrace
&& !(wo
->wo_flags
& WUNTRACED
))
1406 if (!task_stopped_code(p
, ptrace
))
1410 spin_lock_irq(&p
->sighand
->siglock
);
1412 p_code
= task_stopped_code(p
, ptrace
);
1413 if (unlikely(!p_code
))
1416 exit_code
= *p_code
;
1420 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1425 spin_unlock_irq(&p
->sighand
->siglock
);
1430 * Now we are pretty sure this task is interesting.
1431 * Make sure it doesn't get reaped out from under us while we
1432 * give up the lock and then examine it below. We don't want to
1433 * keep holding onto the tasklist_lock while we call getrusage and
1434 * possibly take page faults for user memory.
1437 pid
= task_pid_vnr(p
);
1438 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1439 read_unlock(&tasklist_lock
);
1441 if (unlikely(wo
->wo_flags
& WNOWAIT
))
1442 return wait_noreap_copyout(wo
, p
, pid
, uid
, why
, exit_code
);
1444 retval
= wo
->wo_rusage
1445 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1446 if (!retval
&& wo
->wo_stat
)
1447 retval
= put_user((exit_code
<< 8) | 0x7f, wo
->wo_stat
);
1449 infop
= wo
->wo_info
;
1450 if (!retval
&& infop
)
1451 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1452 if (!retval
&& infop
)
1453 retval
= put_user(0, &infop
->si_errno
);
1454 if (!retval
&& infop
)
1455 retval
= put_user((short)why
, &infop
->si_code
);
1456 if (!retval
&& infop
)
1457 retval
= put_user(exit_code
, &infop
->si_status
);
1458 if (!retval
&& infop
)
1459 retval
= put_user(pid
, &infop
->si_pid
);
1460 if (!retval
&& infop
)
1461 retval
= put_user(uid
, &infop
->si_uid
);
1471 * Handle do_wait work for one task in a live, non-stopped state.
1472 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1473 * the lock and this task is uninteresting. If we return nonzero, we have
1474 * released the lock and the system call should return.
1476 static int wait_task_continued(struct wait_opts
*wo
, struct task_struct
*p
)
1482 if (!unlikely(wo
->wo_flags
& WCONTINUED
))
1485 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1488 spin_lock_irq(&p
->sighand
->siglock
);
1489 /* Re-check with the lock held. */
1490 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1491 spin_unlock_irq(&p
->sighand
->siglock
);
1494 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1495 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1497 spin_unlock_irq(&p
->sighand
->siglock
);
1499 pid
= task_pid_vnr(p
);
1501 read_unlock(&tasklist_lock
);
1504 retval
= wo
->wo_rusage
1505 ? getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
) : 0;
1507 if (!retval
&& wo
->wo_stat
)
1508 retval
= put_user(0xffff, wo
->wo_stat
);
1512 retval
= wait_noreap_copyout(wo
, p
, pid
, uid
,
1513 CLD_CONTINUED
, SIGCONT
);
1514 BUG_ON(retval
== 0);
1521 * Consider @p for a wait by @parent.
1523 * -ECHILD should be in ->notask_error before the first call.
1524 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1525 * Returns zero if the search for a child should continue;
1526 * then ->notask_error is 0 if @p is an eligible child,
1527 * or another error from security_task_wait(), or still -ECHILD.
1529 static int wait_consider_task(struct wait_opts
*wo
, int ptrace
,
1530 struct task_struct
*p
)
1532 int ret
= eligible_child(wo
, p
);
1536 ret
= security_task_wait(p
);
1537 if (unlikely(ret
< 0)) {
1539 * If we have not yet seen any eligible child,
1540 * then let this error code replace -ECHILD.
1541 * A permission error will give the user a clue
1542 * to look for security policy problems, rather
1543 * than for mysterious wait bugs.
1545 if (wo
->notask_error
)
1546 wo
->notask_error
= ret
;
1550 /* dead body doesn't have much to contribute */
1551 if (unlikely(p
->exit_state
== EXIT_DEAD
)) {
1553 * But do not ignore this task until the tracer does
1554 * wait_task_zombie()->do_notify_parent().
1556 if (likely(!ptrace
) && unlikely(ptrace_reparented(p
)))
1557 wo
->notask_error
= 0;
1562 if (p
->exit_state
== EXIT_ZOMBIE
) {
1564 * A zombie ptracee is only visible to its ptracer.
1565 * Notification and reaping will be cascaded to the real
1566 * parent when the ptracer detaches.
1568 if (likely(!ptrace
) && unlikely(p
->ptrace
)) {
1569 /* it will become visible, clear notask_error */
1570 wo
->notask_error
= 0;
1574 /* we don't reap group leaders with subthreads */
1575 if (!delay_group_leader(p
))
1576 return wait_task_zombie(wo
, p
);
1579 * Allow access to stopped/continued state via zombie by
1580 * falling through. Clearing of notask_error is complex.
1584 * If WEXITED is set, notask_error should naturally be
1585 * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
1586 * so, if there are live subthreads, there are events to
1587 * wait for. If all subthreads are dead, it's still safe
1588 * to clear - this function will be called again in finite
1589 * amount time once all the subthreads are released and
1590 * will then return without clearing.
1594 * Stopped state is per-task and thus can't change once the
1595 * target task dies. Only continued and exited can happen.
1596 * Clear notask_error if WCONTINUED | WEXITED.
1598 if (likely(!ptrace
) || (wo
->wo_flags
& (WCONTINUED
| WEXITED
)))
1599 wo
->notask_error
= 0;
1602 * If @p is ptraced by a task in its real parent's group,
1603 * hide group stop/continued state when looking at @p as
1604 * the real parent; otherwise, a single stop can be
1605 * reported twice as group and ptrace stops.
1607 * If a ptracer wants to distinguish the two events for its
1608 * own children, it should create a separate process which
1609 * takes the role of real parent.
1611 if (likely(!ptrace
) && p
->ptrace
&& !ptrace_reparented(p
))
1615 * @p is alive and it's gonna stop, continue or exit, so
1616 * there always is something to wait for.
1618 wo
->notask_error
= 0;
1622 * Wait for stopped. Depending on @ptrace, different stopped state
1623 * is used and the two don't interact with each other.
1625 ret
= wait_task_stopped(wo
, ptrace
, p
);
1630 * Wait for continued. There's only one continued state and the
1631 * ptracer can consume it which can confuse the real parent. Don't
1632 * use WCONTINUED from ptracer. You don't need or want it.
1634 return wait_task_continued(wo
, p
);
1638 * Do the work of do_wait() for one thread in the group, @tsk.
1640 * -ECHILD should be in ->notask_error before the first call.
1641 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1642 * Returns zero if the search for a child should continue; then
1643 * ->notask_error is 0 if there were any eligible children,
1644 * or another error from security_task_wait(), or still -ECHILD.
1646 static int do_wait_thread(struct wait_opts
*wo
, struct task_struct
*tsk
)
1648 struct task_struct
*p
;
1650 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1651 int ret
= wait_consider_task(wo
, 0, p
);
1659 static int ptrace_do_wait(struct wait_opts
*wo
, struct task_struct
*tsk
)
1661 struct task_struct
*p
;
1663 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1664 int ret
= wait_consider_task(wo
, 1, p
);
1672 static int child_wait_callback(wait_queue_t
*wait
, unsigned mode
,
1673 int sync
, void *key
)
1675 struct wait_opts
*wo
= container_of(wait
, struct wait_opts
,
1677 struct task_struct
*p
= key
;
1679 if (!eligible_pid(wo
, p
))
1682 if ((wo
->wo_flags
& __WNOTHREAD
) && wait
->private != p
->parent
)
1685 return default_wake_function(wait
, mode
, sync
, key
);
1688 void __wake_up_parent(struct task_struct
*p
, struct task_struct
*parent
)
1690 __wake_up_sync_key(&parent
->signal
->wait_chldexit
,
1691 TASK_INTERRUPTIBLE
, 1, p
);
1694 static long do_wait(struct wait_opts
*wo
)
1696 struct task_struct
*tsk
;
1699 trace_sched_process_wait(wo
->wo_pid
);
1701 init_waitqueue_func_entry(&wo
->child_wait
, child_wait_callback
);
1702 wo
->child_wait
.private = current
;
1703 add_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1706 * If there is nothing that can match our critiera just get out.
1707 * We will clear ->notask_error to zero if we see any child that
1708 * might later match our criteria, even if we are not able to reap
1711 wo
->notask_error
= -ECHILD
;
1712 if ((wo
->wo_type
< PIDTYPE_MAX
) &&
1713 (!wo
->wo_pid
|| hlist_empty(&wo
->wo_pid
->tasks
[wo
->wo_type
])))
1716 set_current_state(TASK_INTERRUPTIBLE
);
1717 read_lock(&tasklist_lock
);
1720 retval
= do_wait_thread(wo
, tsk
);
1724 retval
= ptrace_do_wait(wo
, tsk
);
1728 if (wo
->wo_flags
& __WNOTHREAD
)
1730 } while_each_thread(current
, tsk
);
1731 read_unlock(&tasklist_lock
);
1734 retval
= wo
->notask_error
;
1735 if (!retval
&& !(wo
->wo_flags
& WNOHANG
)) {
1736 retval
= -ERESTARTSYS
;
1737 if (!signal_pending(current
)) {
1743 __set_current_state(TASK_RUNNING
);
1744 remove_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1748 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1749 infop
, int, options
, struct rusage __user
*, ru
)
1751 struct wait_opts wo
;
1752 struct pid
*pid
= NULL
;
1756 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1758 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1771 type
= PIDTYPE_PGID
;
1779 if (type
< PIDTYPE_MAX
)
1780 pid
= find_get_pid(upid
);
1784 wo
.wo_flags
= options
;
1794 * For a WNOHANG return, clear out all the fields
1795 * we would set so the user can easily tell the
1799 ret
= put_user(0, &infop
->si_signo
);
1801 ret
= put_user(0, &infop
->si_errno
);
1803 ret
= put_user(0, &infop
->si_code
);
1805 ret
= put_user(0, &infop
->si_pid
);
1807 ret
= put_user(0, &infop
->si_uid
);
1809 ret
= put_user(0, &infop
->si_status
);
1814 /* avoid REGPARM breakage on x86: */
1815 asmlinkage_protect(5, ret
, which
, upid
, infop
, options
, ru
);
1819 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1820 int, options
, struct rusage __user
*, ru
)
1822 struct wait_opts wo
;
1823 struct pid
*pid
= NULL
;
1827 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1828 __WNOTHREAD
|__WCLONE
|__WALL
))
1833 else if (upid
< 0) {
1834 type
= PIDTYPE_PGID
;
1835 pid
= find_get_pid(-upid
);
1836 } else if (upid
== 0) {
1837 type
= PIDTYPE_PGID
;
1838 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1839 } else /* upid > 0 */ {
1841 pid
= find_get_pid(upid
);
1846 wo
.wo_flags
= options
| WEXITED
;
1848 wo
.wo_stat
= stat_addr
;
1853 /* avoid REGPARM breakage on x86: */
1854 asmlinkage_protect(4, ret
, upid
, stat_addr
, options
, ru
);
1858 #ifdef __ARCH_WANT_SYS_WAITPID
1861 * sys_waitpid() remains for compatibility. waitpid() should be
1862 * implemented by calling sys_wait4() from libc.a.
1864 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1866 return sys_wait4(pid
, stat_addr
, options
, NULL
);
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