]>
git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - kernel/exit.c
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/mnt_namespace.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/binfmts.h>
23 #include <linux/nsproxy.h>
24 #include <linux/pid_namespace.h>
25 #include <linux/ptrace.h>
26 #include <linux/profile.h>
27 #include <linux/mount.h>
28 #include <linux/proc_fs.h>
29 #include <linux/kthread.h>
30 #include <linux/mempolicy.h>
31 #include <linux/taskstats_kern.h>
32 #include <linux/delayacct.h>
33 #include <linux/freezer.h>
34 #include <linux/cgroup.h>
35 #include <linux/syscalls.h>
36 #include <linux/signal.h>
37 #include <linux/posix-timers.h>
38 #include <linux/cn_proc.h>
39 #include <linux/mutex.h>
40 #include <linux/futex.h>
41 #include <linux/compat.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>
48 #include <asm/uaccess.h>
49 #include <asm/unistd.h>
50 #include <asm/pgtable.h>
51 #include <asm/mmu_context.h>
53 static void exit_mm(struct task_struct
* tsk
);
55 static void __unhash_process(struct task_struct
*p
)
58 detach_pid(p
, PIDTYPE_PID
);
59 if (thread_group_leader(p
)) {
60 detach_pid(p
, PIDTYPE_PGID
);
61 detach_pid(p
, PIDTYPE_SID
);
63 list_del_rcu(&p
->tasks
);
64 __get_cpu_var(process_counts
)--;
66 list_del_rcu(&p
->thread_group
);
71 * This function expects the tasklist_lock write-locked.
73 static void __exit_signal(struct task_struct
*tsk
)
75 struct signal_struct
*sig
= tsk
->signal
;
76 struct sighand_struct
*sighand
;
79 BUG_ON(!atomic_read(&sig
->count
));
82 sighand
= rcu_dereference(tsk
->sighand
);
83 spin_lock(&sighand
->siglock
);
85 posix_cpu_timers_exit(tsk
);
86 if (atomic_dec_and_test(&sig
->count
))
87 posix_cpu_timers_exit_group(tsk
);
90 * If there is any task waiting for the group exit
93 if (sig
->group_exit_task
&& atomic_read(&sig
->count
) == sig
->notify_count
)
94 wake_up_process(sig
->group_exit_task
);
96 if (tsk
== sig
->curr_target
)
97 sig
->curr_target
= next_thread(tsk
);
99 * Accumulate here the counters for all threads but the
100 * group leader as they die, so they can be added into
101 * the process-wide totals when those are taken.
102 * The group leader stays around as a zombie as long
103 * as there are other threads. When it gets reaped,
104 * the exit.c code will add its counts into these totals.
105 * We won't ever get here for the group leader, since it
106 * will have been the last reference on the signal_struct.
108 sig
->utime
= cputime_add(sig
->utime
, tsk
->utime
);
109 sig
->stime
= cputime_add(sig
->stime
, tsk
->stime
);
110 sig
->gtime
= cputime_add(sig
->gtime
, tsk
->gtime
);
111 sig
->min_flt
+= tsk
->min_flt
;
112 sig
->maj_flt
+= tsk
->maj_flt
;
113 sig
->nvcsw
+= tsk
->nvcsw
;
114 sig
->nivcsw
+= tsk
->nivcsw
;
115 sig
->inblock
+= task_io_get_inblock(tsk
);
116 sig
->oublock
+= task_io_get_oublock(tsk
);
117 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
118 sig
= NULL
; /* Marker for below. */
121 __unhash_process(tsk
);
125 spin_unlock(&sighand
->siglock
);
128 __cleanup_sighand(sighand
);
129 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
130 flush_sigqueue(&tsk
->pending
);
132 flush_sigqueue(&sig
->shared_pending
);
133 taskstats_tgid_free(sig
);
134 __cleanup_signal(sig
);
138 static void delayed_put_task_struct(struct rcu_head
*rhp
)
140 put_task_struct(container_of(rhp
, struct task_struct
, rcu
));
143 void release_task(struct task_struct
* p
)
145 struct task_struct
*leader
;
148 atomic_dec(&p
->user
->processes
);
150 write_lock_irq(&tasklist_lock
);
152 BUG_ON(!list_empty(&p
->ptrace_list
) || !list_empty(&p
->ptrace_children
));
156 * If we are the last non-leader member of the thread
157 * group, and the leader is zombie, then notify the
158 * group leader's parent process. (if it wants notification.)
161 leader
= p
->group_leader
;
162 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
163 BUG_ON(leader
->exit_signal
== -1);
164 do_notify_parent(leader
, leader
->exit_signal
);
166 * If we were the last child thread and the leader has
167 * exited already, and the leader's parent ignores SIGCHLD,
168 * then we are the one who should release the leader.
170 * do_notify_parent() will have marked it self-reaping in
173 zap_leader
= (leader
->exit_signal
== -1);
176 write_unlock_irq(&tasklist_lock
);
178 call_rcu(&p
->rcu
, delayed_put_task_struct
);
181 if (unlikely(zap_leader
))
186 * This checks not only the pgrp, but falls back on the pid if no
187 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
190 * The caller must hold rcu lock or the tasklist lock.
192 struct pid
*session_of_pgrp(struct pid
*pgrp
)
194 struct task_struct
*p
;
195 struct pid
*sid
= NULL
;
197 p
= pid_task(pgrp
, PIDTYPE_PGID
);
199 p
= pid_task(pgrp
, PIDTYPE_PID
);
201 sid
= task_session(p
);
207 * Determine if a process group is "orphaned", according to the POSIX
208 * definition in 2.2.2.52. Orphaned process groups are not to be affected
209 * by terminal-generated stop signals. Newly orphaned process groups are
210 * to receive a SIGHUP and a SIGCONT.
212 * "I ask you, have you ever known what it is to be an orphan?"
214 static int will_become_orphaned_pgrp(struct pid
*pgrp
, struct task_struct
*ignored_task
)
216 struct task_struct
*p
;
218 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
219 if ((p
== ignored_task
) ||
220 (p
->exit_state
&& thread_group_empty(p
)) ||
221 is_global_init(p
->real_parent
))
224 if (task_pgrp(p
->real_parent
) != pgrp
&&
225 task_session(p
->real_parent
) == task_session(p
))
227 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
232 int is_current_pgrp_orphaned(void)
236 read_lock(&tasklist_lock
);
237 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
238 read_unlock(&tasklist_lock
);
243 static int has_stopped_jobs(struct pid
*pgrp
)
246 struct task_struct
*p
;
248 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
249 if (!task_is_stopped(p
))
253 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
258 * Check to see if any process groups have become orphaned as
259 * a result of our exiting, and if they have any stopped jobs,
260 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
263 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
265 struct pid
*pgrp
= task_pgrp(tsk
);
266 struct task_struct
*ignored_task
= tsk
;
269 /* exit: our father is in a different pgrp than
270 * we are and we were the only connection outside.
272 parent
= tsk
->real_parent
;
274 /* reparent: our child is in a different pgrp than
275 * we are, and it was the only connection outside.
279 if (task_pgrp(parent
) != pgrp
&&
280 task_session(parent
) == task_session(tsk
) &&
281 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
282 has_stopped_jobs(pgrp
)) {
283 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
284 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
289 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
291 * If a kernel thread is launched as a result of a system call, or if
292 * it ever exits, it should generally reparent itself to kthreadd so it
293 * isn't in the way of other processes and is correctly cleaned up on exit.
295 * The various task state such as scheduling policy and priority may have
296 * been inherited from a user process, so we reset them to sane values here.
298 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
300 static void reparent_to_kthreadd(void)
302 write_lock_irq(&tasklist_lock
);
304 ptrace_unlink(current
);
305 /* Reparent to init */
306 remove_parent(current
);
307 current
->real_parent
= current
->parent
= kthreadd_task
;
310 /* Set the exit signal to SIGCHLD so we signal init on exit */
311 current
->exit_signal
= SIGCHLD
;
313 if (task_nice(current
) < 0)
314 set_user_nice(current
, 0);
318 security_task_reparent_to_init(current
);
319 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
320 sizeof(current
->signal
->rlim
));
321 atomic_inc(&(INIT_USER
->__count
));
322 write_unlock_irq(&tasklist_lock
);
323 switch_uid(INIT_USER
);
326 void __set_special_pids(struct pid
*pid
)
328 struct task_struct
*curr
= current
->group_leader
;
329 pid_t nr
= pid_nr(pid
);
331 if (task_session(curr
) != pid
) {
332 detach_pid(curr
, PIDTYPE_SID
);
333 attach_pid(curr
, PIDTYPE_SID
, pid
);
334 set_task_session(curr
, nr
);
336 if (task_pgrp(curr
) != pid
) {
337 detach_pid(curr
, PIDTYPE_PGID
);
338 attach_pid(curr
, PIDTYPE_PGID
, pid
);
339 set_task_pgrp(curr
, nr
);
343 static void set_special_pids(struct pid
*pid
)
345 write_lock_irq(&tasklist_lock
);
346 __set_special_pids(pid
);
347 write_unlock_irq(&tasklist_lock
);
351 * Let kernel threads use this to say that they
352 * allow a certain signal (since daemonize() will
353 * have disabled all of them by default).
355 int allow_signal(int sig
)
357 if (!valid_signal(sig
) || sig
< 1)
360 spin_lock_irq(¤t
->sighand
->siglock
);
361 sigdelset(¤t
->blocked
, sig
);
363 /* Kernel threads handle their own signals.
364 Let the signal code know it'll be handled, so
365 that they don't get converted to SIGKILL or
366 just silently dropped */
367 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
370 spin_unlock_irq(¤t
->sighand
->siglock
);
374 EXPORT_SYMBOL(allow_signal
);
376 int disallow_signal(int sig
)
378 if (!valid_signal(sig
) || sig
< 1)
381 spin_lock_irq(¤t
->sighand
->siglock
);
382 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= SIG_IGN
;
384 spin_unlock_irq(¤t
->sighand
->siglock
);
388 EXPORT_SYMBOL(disallow_signal
);
391 * Put all the gunge required to become a kernel thread without
392 * attached user resources in one place where it belongs.
395 void daemonize(const char *name
, ...)
398 struct fs_struct
*fs
;
401 va_start(args
, name
);
402 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
406 * If we were started as result of loading a module, close all of the
407 * user space pages. We don't need them, and if we didn't close them
408 * they would be locked into memory.
412 * We don't want to have TIF_FREEZE set if the system-wide hibernation
413 * or suspend transition begins right now.
415 current
->flags
|= PF_NOFREEZE
;
417 if (current
->nsproxy
!= &init_nsproxy
) {
418 get_nsproxy(&init_nsproxy
);
419 switch_task_namespaces(current
, &init_nsproxy
);
421 set_special_pids(&init_struct_pid
);
422 proc_clear_tty(current
);
424 /* Block and flush all signals */
425 sigfillset(&blocked
);
426 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
427 flush_signals(current
);
429 /* Become as one with the init task */
431 exit_fs(current
); /* current->fs->count--; */
434 atomic_inc(&fs
->count
);
437 current
->files
= init_task
.files
;
438 atomic_inc(¤t
->files
->count
);
440 reparent_to_kthreadd();
443 EXPORT_SYMBOL(daemonize
);
445 static void close_files(struct files_struct
* files
)
453 * It is safe to dereference the fd table without RCU or
454 * ->file_lock because this is the last reference to the
457 fdt
= files_fdtable(files
);
461 if (i
>= fdt
->max_fds
)
463 set
= fdt
->open_fds
->fds_bits
[j
++];
466 struct file
* file
= xchg(&fdt
->fd
[i
], NULL
);
468 filp_close(file
, files
);
478 struct files_struct
*get_files_struct(struct task_struct
*task
)
480 struct files_struct
*files
;
485 atomic_inc(&files
->count
);
491 void put_files_struct(struct files_struct
*files
)
495 if (atomic_dec_and_test(&files
->count
)) {
498 * Free the fd and fdset arrays if we expanded them.
499 * If the fdtable was embedded, pass files for freeing
500 * at the end of the RCU grace period. Otherwise,
501 * you can free files immediately.
503 fdt
= files_fdtable(files
);
504 if (fdt
!= &files
->fdtab
)
505 kmem_cache_free(files_cachep
, files
);
510 EXPORT_SYMBOL(put_files_struct
);
512 void reset_files_struct(struct task_struct
*tsk
, struct files_struct
*files
)
514 struct files_struct
*old
;
520 put_files_struct(old
);
522 EXPORT_SYMBOL(reset_files_struct
);
524 static void __exit_files(struct task_struct
*tsk
)
526 struct files_struct
* files
= tsk
->files
;
532 put_files_struct(files
);
536 void exit_files(struct task_struct
*tsk
)
541 static void __put_fs_struct(struct fs_struct
*fs
)
543 /* No need to hold fs->lock if we are killing it */
544 if (atomic_dec_and_test(&fs
->count
)) {
547 if (fs
->altroot
.dentry
)
548 path_put(&fs
->altroot
);
549 kmem_cache_free(fs_cachep
, fs
);
553 void put_fs_struct(struct fs_struct
*fs
)
558 static void __exit_fs(struct task_struct
*tsk
)
560 struct fs_struct
* fs
= tsk
->fs
;
570 void exit_fs(struct task_struct
*tsk
)
575 EXPORT_SYMBOL_GPL(exit_fs
);
578 * Turn us into a lazy TLB process if we
581 static void exit_mm(struct task_struct
* tsk
)
583 struct mm_struct
*mm
= tsk
->mm
;
589 * Serialize with any possible pending coredump.
590 * We must hold mmap_sem around checking core_waiters
591 * and clearing tsk->mm. The core-inducing thread
592 * will increment core_waiters for each thread in the
593 * group with ->mm != NULL.
595 down_read(&mm
->mmap_sem
);
596 if (mm
->core_waiters
) {
597 up_read(&mm
->mmap_sem
);
598 down_write(&mm
->mmap_sem
);
599 if (!--mm
->core_waiters
)
600 complete(mm
->core_startup_done
);
601 up_write(&mm
->mmap_sem
);
603 wait_for_completion(&mm
->core_done
);
604 down_read(&mm
->mmap_sem
);
606 atomic_inc(&mm
->mm_count
);
607 BUG_ON(mm
!= tsk
->active_mm
);
608 /* more a memory barrier than a real lock */
611 up_read(&mm
->mmap_sem
);
612 enter_lazy_tlb(mm
, current
);
613 /* We don't want this task to be frozen prematurely */
614 clear_freeze_flag(tsk
);
620 reparent_thread(struct task_struct
*p
, struct task_struct
*father
, int traced
)
622 if (p
->pdeath_signal
)
623 /* We already hold the tasklist_lock here. */
624 group_send_sig_info(p
->pdeath_signal
, SEND_SIG_NOINFO
, p
);
626 /* Move the child from its dying parent to the new one. */
627 if (unlikely(traced
)) {
628 /* Preserve ptrace links if someone else is tracing this child. */
629 list_del_init(&p
->ptrace_list
);
630 if (p
->parent
!= p
->real_parent
)
631 list_add(&p
->ptrace_list
, &p
->real_parent
->ptrace_children
);
633 /* If this child is being traced, then we're the one tracing it
634 * anyway, so let go of it.
638 p
->parent
= p
->real_parent
;
641 if (task_is_traced(p
)) {
643 * If it was at a trace stop, turn it into
644 * a normal stop since it's no longer being
651 /* If this is a threaded reparent there is no need to
652 * notify anyone anything has happened.
654 if (p
->real_parent
->group_leader
== father
->group_leader
)
657 /* We don't want people slaying init. */
658 if (p
->exit_signal
!= -1)
659 p
->exit_signal
= SIGCHLD
;
661 /* If we'd notified the old parent about this child's death,
662 * also notify the new parent.
664 if (!traced
&& p
->exit_state
== EXIT_ZOMBIE
&&
665 p
->exit_signal
!= -1 && thread_group_empty(p
))
666 do_notify_parent(p
, p
->exit_signal
);
668 kill_orphaned_pgrp(p
, father
);
672 * When we die, we re-parent all our children.
673 * Try to give them to another thread in our thread
674 * group, and if no such member exists, give it to
675 * the child reaper process (ie "init") in our pid
678 static void forget_original_parent(struct task_struct
*father
)
680 struct task_struct
*p
, *n
, *reaper
= father
;
681 struct list_head ptrace_dead
;
683 INIT_LIST_HEAD(&ptrace_dead
);
685 write_lock_irq(&tasklist_lock
);
688 reaper
= next_thread(reaper
);
689 if (reaper
== father
) {
690 reaper
= task_child_reaper(father
);
693 } while (reaper
->flags
& PF_EXITING
);
696 * There are only two places where our children can be:
698 * - in our child list
699 * - in our ptraced child list
701 * Search them and reparent children.
703 list_for_each_entry_safe(p
, n
, &father
->children
, sibling
) {
708 /* if father isn't the real parent, then ptrace must be enabled */
709 BUG_ON(father
!= p
->real_parent
&& !ptrace
);
711 if (father
== p
->real_parent
) {
712 /* reparent with a reaper, real father it's us */
713 p
->real_parent
= reaper
;
714 reparent_thread(p
, father
, 0);
716 /* reparent ptraced task to its real parent */
718 if (p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
!= -1 &&
719 thread_group_empty(p
))
720 do_notify_parent(p
, p
->exit_signal
);
724 * if the ptraced child is a zombie with exit_signal == -1
725 * we must collect it before we exit, or it will remain
726 * zombie forever since we prevented it from self-reap itself
727 * while it was being traced by us, to be able to see it in wait4.
729 if (unlikely(ptrace
&& p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
== -1))
730 list_add(&p
->ptrace_list
, &ptrace_dead
);
733 list_for_each_entry_safe(p
, n
, &father
->ptrace_children
, ptrace_list
) {
734 p
->real_parent
= reaper
;
735 reparent_thread(p
, father
, 1);
738 write_unlock_irq(&tasklist_lock
);
739 BUG_ON(!list_empty(&father
->children
));
740 BUG_ON(!list_empty(&father
->ptrace_children
));
742 list_for_each_entry_safe(p
, n
, &ptrace_dead
, ptrace_list
) {
743 list_del_init(&p
->ptrace_list
);
750 * Send signals to all our closest relatives so that they know
751 * to properly mourn us..
753 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
758 * This does two things:
760 * A. Make init inherit all the child processes
761 * B. Check to see if any process groups have become orphaned
762 * as a result of our exiting, and if they have any stopped
763 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
765 forget_original_parent(tsk
);
766 exit_task_namespaces(tsk
);
768 write_lock_irq(&tasklist_lock
);
770 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
772 /* Let father know we died
774 * Thread signals are configurable, but you aren't going to use
775 * that to send signals to arbitary processes.
776 * That stops right now.
778 * If the parent exec id doesn't match the exec id we saved
779 * when we started then we know the parent has changed security
782 * If our self_exec id doesn't match our parent_exec_id then
783 * we have changed execution domain as these two values started
784 * the same after a fork.
786 if (tsk
->exit_signal
!= SIGCHLD
&& tsk
->exit_signal
!= -1 &&
787 (tsk
->parent_exec_id
!= tsk
->real_parent
->self_exec_id
||
788 tsk
->self_exec_id
!= tsk
->parent_exec_id
)
789 && !capable(CAP_KILL
))
790 tsk
->exit_signal
= SIGCHLD
;
793 /* If something other than our normal parent is ptracing us, then
794 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
795 * only has special meaning to our real parent.
797 if (tsk
->exit_signal
!= -1 && thread_group_empty(tsk
)) {
798 int signal
= tsk
->parent
== tsk
->real_parent
? tsk
->exit_signal
: SIGCHLD
;
799 do_notify_parent(tsk
, signal
);
800 } else if (tsk
->ptrace
) {
801 do_notify_parent(tsk
, SIGCHLD
);
805 if (tsk
->exit_signal
== -1 && likely(!tsk
->ptrace
))
807 tsk
->exit_state
= state
;
809 if (thread_group_leader(tsk
) &&
810 tsk
->signal
->notify_count
< 0 &&
811 tsk
->signal
->group_exit_task
)
812 wake_up_process(tsk
->signal
->group_exit_task
);
814 write_unlock_irq(&tasklist_lock
);
816 /* If the process is dead, release it - nobody will wait for it */
817 if (state
== EXIT_DEAD
)
821 #ifdef CONFIG_DEBUG_STACK_USAGE
822 static void check_stack_usage(void)
824 static DEFINE_SPINLOCK(low_water_lock
);
825 static int lowest_to_date
= THREAD_SIZE
;
826 unsigned long *n
= end_of_stack(current
);
831 free
= (unsigned long)n
- (unsigned long)end_of_stack(current
);
833 if (free
>= lowest_to_date
)
836 spin_lock(&low_water_lock
);
837 if (free
< lowest_to_date
) {
838 printk(KERN_WARNING
"%s used greatest stack depth: %lu bytes "
840 current
->comm
, free
);
841 lowest_to_date
= free
;
843 spin_unlock(&low_water_lock
);
846 static inline void check_stack_usage(void) {}
849 static inline void exit_child_reaper(struct task_struct
*tsk
)
851 if (likely(tsk
->group_leader
!= task_child_reaper(tsk
)))
854 if (tsk
->nsproxy
->pid_ns
== &init_pid_ns
)
855 panic("Attempted to kill init!");
858 * @tsk is the last thread in the 'cgroup-init' and is exiting.
859 * Terminate all remaining processes in the namespace and reap them
860 * before exiting @tsk.
862 * Note that @tsk (last thread of cgroup-init) may not necessarily
863 * be the child-reaper (i.e main thread of cgroup-init) of the
864 * namespace i.e the child_reaper may have already exited.
866 * Even after a child_reaper exits, we let it inherit orphaned children,
867 * because, pid_ns->child_reaper remains valid as long as there is
868 * at least one living sub-thread in the cgroup init.
870 * This living sub-thread of the cgroup-init will be notified when
871 * a child inherited by the 'child-reaper' exits (do_notify_parent()
872 * uses __group_send_sig_info()). Further, when reaping child processes,
873 * do_wait() iterates over children of all living sub threads.
875 * i.e even though 'child_reaper' thread is listed as the parent of the
876 * orphaned children, any living sub-thread in the cgroup-init can
877 * perform the role of the child_reaper.
879 zap_pid_ns_processes(tsk
->nsproxy
->pid_ns
);
882 NORET_TYPE
void do_exit(long code
)
884 struct task_struct
*tsk
= current
;
887 profile_task_exit(tsk
);
889 WARN_ON(atomic_read(&tsk
->fs_excl
));
891 if (unlikely(in_interrupt()))
892 panic("Aiee, killing interrupt handler!");
893 if (unlikely(!tsk
->pid
))
894 panic("Attempted to kill the idle task!");
896 if (unlikely(current
->ptrace
& PT_TRACE_EXIT
)) {
897 current
->ptrace_message
= code
;
898 ptrace_notify((PTRACE_EVENT_EXIT
<< 8) | SIGTRAP
);
902 * We're taking recursive faults here in do_exit. Safest is to just
903 * leave this task alone and wait for reboot.
905 if (unlikely(tsk
->flags
& PF_EXITING
)) {
907 "Fixing recursive fault but reboot is needed!\n");
909 * We can do this unlocked here. The futex code uses
910 * this flag just to verify whether the pi state
911 * cleanup has been done or not. In the worst case it
912 * loops once more. We pretend that the cleanup was
913 * done as there is no way to return. Either the
914 * OWNER_DIED bit is set by now or we push the blocked
915 * task into the wait for ever nirwana as well.
917 tsk
->flags
|= PF_EXITPIDONE
;
920 set_current_state(TASK_UNINTERRUPTIBLE
);
924 exit_signals(tsk
); /* sets PF_EXITING */
926 * tsk->flags are checked in the futex code to protect against
927 * an exiting task cleaning up the robust pi futexes.
930 spin_unlock_wait(&tsk
->pi_lock
);
932 if (unlikely(in_atomic()))
933 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
934 current
->comm
, task_pid_nr(current
),
937 acct_update_integrals(tsk
);
939 update_hiwater_rss(tsk
->mm
);
940 update_hiwater_vm(tsk
->mm
);
942 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
944 exit_child_reaper(tsk
);
945 hrtimer_cancel(&tsk
->signal
->real_timer
);
946 exit_itimers(tsk
->signal
);
948 acct_collect(code
, group_dead
);
950 if (unlikely(tsk
->robust_list
))
951 exit_robust_list(tsk
);
953 if (unlikely(tsk
->compat_robust_list
))
954 compat_exit_robust_list(tsk
);
959 if (unlikely(tsk
->audit_context
))
962 tsk
->exit_code
= code
;
963 taskstats_exit(tsk
, group_dead
);
977 if (group_dead
&& tsk
->signal
->leader
)
978 disassociate_ctty(1);
980 module_put(task_thread_info(tsk
)->exec_domain
->module
);
982 module_put(tsk
->binfmt
->module
);
984 proc_exit_connector(tsk
);
985 exit_notify(tsk
, group_dead
);
987 mpol_free(tsk
->mempolicy
);
988 tsk
->mempolicy
= NULL
;
992 * This must happen late, after the PID is not
995 if (unlikely(!list_empty(&tsk
->pi_state_list
)))
996 exit_pi_state_list(tsk
);
997 if (unlikely(current
->pi_state_cache
))
998 kfree(current
->pi_state_cache
);
1001 * Make sure we are holding no locks:
1003 debug_check_no_locks_held(tsk
);
1005 * We can do this unlocked here. The futex code uses this flag
1006 * just to verify whether the pi state cleanup has been done
1007 * or not. In the worst case it loops once more.
1009 tsk
->flags
|= PF_EXITPIDONE
;
1011 if (tsk
->io_context
)
1014 if (tsk
->splice_pipe
)
1015 __free_pipe_info(tsk
->splice_pipe
);
1018 /* causes final put_task_struct in finish_task_switch(). */
1019 tsk
->state
= TASK_DEAD
;
1023 /* Avoid "noreturn function does return". */
1025 cpu_relax(); /* For when BUG is null */
1028 EXPORT_SYMBOL_GPL(do_exit
);
1030 NORET_TYPE
void complete_and_exit(struct completion
*comp
, long code
)
1038 EXPORT_SYMBOL(complete_and_exit
);
1040 asmlinkage
long sys_exit(int error_code
)
1042 do_exit((error_code
&0xff)<<8);
1046 * Take down every thread in the group. This is called by fatal signals
1047 * as well as by sys_exit_group (below).
1050 do_group_exit(int exit_code
)
1052 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
1054 if (current
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1055 exit_code
= current
->signal
->group_exit_code
;
1056 else if (!thread_group_empty(current
)) {
1057 struct signal_struct
*const sig
= current
->signal
;
1058 struct sighand_struct
*const sighand
= current
->sighand
;
1059 spin_lock_irq(&sighand
->siglock
);
1060 if (signal_group_exit(sig
))
1061 /* Another thread got here before we took the lock. */
1062 exit_code
= sig
->group_exit_code
;
1064 sig
->group_exit_code
= exit_code
;
1065 sig
->flags
= SIGNAL_GROUP_EXIT
;
1066 zap_other_threads(current
);
1068 spin_unlock_irq(&sighand
->siglock
);
1076 * this kills every thread in the thread group. Note that any externally
1077 * wait4()-ing process will get the correct exit code - even if this
1078 * thread is not the thread group leader.
1080 asmlinkage
void sys_exit_group(int error_code
)
1082 do_group_exit((error_code
& 0xff) << 8);
1085 static struct pid
*task_pid_type(struct task_struct
*task
, enum pid_type type
)
1087 struct pid
*pid
= NULL
;
1088 if (type
== PIDTYPE_PID
)
1089 pid
= task
->pids
[type
].pid
;
1090 else if (type
< PIDTYPE_MAX
)
1091 pid
= task
->group_leader
->pids
[type
].pid
;
1095 static int eligible_child(enum pid_type type
, struct pid
*pid
, int options
,
1096 struct task_struct
*p
)
1100 if (type
< PIDTYPE_MAX
) {
1101 if (task_pid_type(p
, type
) != pid
)
1106 * Do not consider detached threads that are
1109 if (p
->exit_signal
== -1 && !p
->ptrace
)
1112 /* Wait for all children (clone and not) if __WALL is set;
1113 * otherwise, wait for clone children *only* if __WCLONE is
1114 * set; otherwise, wait for non-clone children *only*. (Note:
1115 * A "clone" child here is one that reports to its parent
1116 * using a signal other than SIGCHLD.) */
1117 if (((p
->exit_signal
!= SIGCHLD
) ^ ((options
& __WCLONE
) != 0))
1118 && !(options
& __WALL
))
1121 err
= security_task_wait(p
);
1125 if (type
!= PIDTYPE_PID
)
1127 /* This child was explicitly requested, abort */
1128 read_unlock(&tasklist_lock
);
1132 static int wait_noreap_copyout(struct task_struct
*p
, pid_t pid
, uid_t uid
,
1133 int why
, int status
,
1134 struct siginfo __user
*infop
,
1135 struct rusage __user
*rusagep
)
1137 int retval
= rusagep
? getrusage(p
, RUSAGE_BOTH
, rusagep
) : 0;
1141 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1143 retval
= put_user(0, &infop
->si_errno
);
1145 retval
= put_user((short)why
, &infop
->si_code
);
1147 retval
= put_user(pid
, &infop
->si_pid
);
1149 retval
= put_user(uid
, &infop
->si_uid
);
1151 retval
= put_user(status
, &infop
->si_status
);
1158 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1159 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1160 * the lock and this task is uninteresting. If we return nonzero, we have
1161 * released the lock and the system call should return.
1163 static int wait_task_zombie(struct task_struct
*p
, int noreap
,
1164 struct siginfo __user
*infop
,
1165 int __user
*stat_addr
, struct rusage __user
*ru
)
1167 unsigned long state
;
1168 int retval
, status
, traced
;
1169 pid_t pid
= task_pid_vnr(p
);
1171 if (unlikely(noreap
)) {
1173 int exit_code
= p
->exit_code
;
1177 read_unlock(&tasklist_lock
);
1178 if ((exit_code
& 0x7f) == 0) {
1180 status
= exit_code
>> 8;
1182 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1183 status
= exit_code
& 0x7f;
1185 return wait_noreap_copyout(p
, pid
, uid
, why
,
1190 * Try to move the task's state to DEAD
1191 * only one thread is allowed to do this:
1193 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1194 if (state
!= EXIT_ZOMBIE
) {
1195 BUG_ON(state
!= EXIT_DEAD
);
1199 /* traced means p->ptrace, but not vice versa */
1200 traced
= (p
->real_parent
!= p
->parent
);
1202 if (likely(!traced
)) {
1203 struct signal_struct
*psig
;
1204 struct signal_struct
*sig
;
1207 * The resource counters for the group leader are in its
1208 * own task_struct. Those for dead threads in the group
1209 * are in its signal_struct, as are those for the child
1210 * processes it has previously reaped. All these
1211 * accumulate in the parent's signal_struct c* fields.
1213 * We don't bother to take a lock here to protect these
1214 * p->signal fields, because they are only touched by
1215 * __exit_signal, which runs with tasklist_lock
1216 * write-locked anyway, and so is excluded here. We do
1217 * need to protect the access to p->parent->signal fields,
1218 * as other threads in the parent group can be right
1219 * here reaping other children at the same time.
1221 spin_lock_irq(&p
->parent
->sighand
->siglock
);
1222 psig
= p
->parent
->signal
;
1225 cputime_add(psig
->cutime
,
1226 cputime_add(p
->utime
,
1227 cputime_add(sig
->utime
,
1230 cputime_add(psig
->cstime
,
1231 cputime_add(p
->stime
,
1232 cputime_add(sig
->stime
,
1235 cputime_add(psig
->cgtime
,
1236 cputime_add(p
->gtime
,
1237 cputime_add(sig
->gtime
,
1240 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1242 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1244 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1246 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1248 task_io_get_inblock(p
) +
1249 sig
->inblock
+ sig
->cinblock
;
1251 task_io_get_oublock(p
) +
1252 sig
->oublock
+ sig
->coublock
;
1253 spin_unlock_irq(&p
->parent
->sighand
->siglock
);
1257 * Now we are sure this task is interesting, and no other
1258 * thread can reap it because we set its state to EXIT_DEAD.
1260 read_unlock(&tasklist_lock
);
1262 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1263 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1264 ? p
->signal
->group_exit_code
: p
->exit_code
;
1265 if (!retval
&& stat_addr
)
1266 retval
= put_user(status
, stat_addr
);
1267 if (!retval
&& infop
)
1268 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1269 if (!retval
&& infop
)
1270 retval
= put_user(0, &infop
->si_errno
);
1271 if (!retval
&& infop
) {
1274 if ((status
& 0x7f) == 0) {
1278 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1281 retval
= put_user((short)why
, &infop
->si_code
);
1283 retval
= put_user(status
, &infop
->si_status
);
1285 if (!retval
&& infop
)
1286 retval
= put_user(pid
, &infop
->si_pid
);
1287 if (!retval
&& infop
)
1288 retval
= put_user(p
->uid
, &infop
->si_uid
);
1293 write_lock_irq(&tasklist_lock
);
1294 /* We dropped tasklist, ptracer could die and untrace */
1297 * If this is not a detached task, notify the parent.
1298 * If it's still not detached after that, don't release
1301 if (p
->exit_signal
!= -1) {
1302 do_notify_parent(p
, p
->exit_signal
);
1303 if (p
->exit_signal
!= -1) {
1304 p
->exit_state
= EXIT_ZOMBIE
;
1308 write_unlock_irq(&tasklist_lock
);
1317 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1318 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1319 * the lock and this task is uninteresting. If we return nonzero, we have
1320 * released the lock and the system call should return.
1322 static int wait_task_stopped(struct task_struct
*p
,
1323 int noreap
, struct siginfo __user
*infop
,
1324 int __user
*stat_addr
, struct rusage __user
*ru
)
1326 int retval
, exit_code
, why
;
1327 uid_t uid
= 0; /* unneeded, required by compiler */
1331 spin_lock_irq(&p
->sighand
->siglock
);
1333 if (unlikely(!task_is_stopped_or_traced(p
)))
1336 if (!(p
->ptrace
& PT_PTRACED
) && p
->signal
->group_stop_count
> 0)
1338 * A group stop is in progress and this is the group leader.
1339 * We won't report until all threads have stopped.
1343 exit_code
= p
->exit_code
;
1352 spin_unlock_irq(&p
->sighand
->siglock
);
1357 * Now we are pretty sure this task is interesting.
1358 * Make sure it doesn't get reaped out from under us while we
1359 * give up the lock and then examine it below. We don't want to
1360 * keep holding onto the tasklist_lock while we call getrusage and
1361 * possibly take page faults for user memory.
1364 pid
= task_pid_vnr(p
);
1365 why
= (p
->ptrace
& PT_PTRACED
) ? CLD_TRAPPED
: CLD_STOPPED
;
1366 read_unlock(&tasklist_lock
);
1368 if (unlikely(noreap
))
1369 return wait_noreap_copyout(p
, pid
, uid
,
1373 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1374 if (!retval
&& stat_addr
)
1375 retval
= put_user((exit_code
<< 8) | 0x7f, stat_addr
);
1376 if (!retval
&& infop
)
1377 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1378 if (!retval
&& infop
)
1379 retval
= put_user(0, &infop
->si_errno
);
1380 if (!retval
&& infop
)
1381 retval
= put_user((short)why
, &infop
->si_code
);
1382 if (!retval
&& infop
)
1383 retval
= put_user(exit_code
, &infop
->si_status
);
1384 if (!retval
&& infop
)
1385 retval
= put_user(pid
, &infop
->si_pid
);
1386 if (!retval
&& infop
)
1387 retval
= put_user(uid
, &infop
->si_uid
);
1397 * Handle do_wait work for one task in a live, non-stopped state.
1398 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1399 * the lock and this task is uninteresting. If we return nonzero, we have
1400 * released the lock and the system call should return.
1402 static int wait_task_continued(struct task_struct
*p
, int noreap
,
1403 struct siginfo __user
*infop
,
1404 int __user
*stat_addr
, struct rusage __user
*ru
)
1410 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1413 spin_lock_irq(&p
->sighand
->siglock
);
1414 /* Re-check with the lock held. */
1415 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1416 spin_unlock_irq(&p
->sighand
->siglock
);
1420 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1421 spin_unlock_irq(&p
->sighand
->siglock
);
1423 pid
= task_pid_vnr(p
);
1426 read_unlock(&tasklist_lock
);
1429 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1431 if (!retval
&& stat_addr
)
1432 retval
= put_user(0xffff, stat_addr
);
1436 retval
= wait_noreap_copyout(p
, pid
, uid
,
1437 CLD_CONTINUED
, SIGCONT
,
1439 BUG_ON(retval
== 0);
1445 static long do_wait(enum pid_type type
, struct pid
*pid
, int options
,
1446 struct siginfo __user
*infop
, int __user
*stat_addr
,
1447 struct rusage __user
*ru
)
1449 DECLARE_WAITQUEUE(wait
, current
);
1450 struct task_struct
*tsk
;
1453 add_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1455 /* If there is nothing that can match our critier just get out */
1457 if ((type
< PIDTYPE_MAX
) && (!pid
|| hlist_empty(&pid
->tasks
[type
])))
1461 * We will set this flag if we see any child that might later
1462 * match our criteria, even if we are not able to reap it yet.
1465 current
->state
= TASK_INTERRUPTIBLE
;
1466 read_lock(&tasklist_lock
);
1469 struct task_struct
*p
;
1471 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1472 int ret
= eligible_child(type
, pid
, options
, p
);
1476 if (unlikely(ret
< 0)) {
1478 } else if (task_is_stopped_or_traced(p
)) {
1480 * It's stopped now, so it might later
1481 * continue, exit, or stop again.
1484 if (!(p
->ptrace
& PT_PTRACED
) &&
1485 !(options
& WUNTRACED
))
1488 retval
= wait_task_stopped(p
,
1489 (options
& WNOWAIT
), infop
,
1491 } else if (p
->exit_state
== EXIT_ZOMBIE
&&
1492 !delay_group_leader(p
)) {
1494 * We don't reap group leaders with subthreads.
1496 if (!likely(options
& WEXITED
))
1498 retval
= wait_task_zombie(p
,
1499 (options
& WNOWAIT
), infop
,
1501 } else if (p
->exit_state
!= EXIT_DEAD
) {
1503 * It's running now, so it might later
1504 * exit, stop, or stop and then continue.
1507 if (!unlikely(options
& WCONTINUED
))
1509 retval
= wait_task_continued(p
,
1510 (options
& WNOWAIT
), infop
,
1513 if (retval
!= 0) /* tasklist_lock released */
1517 list_for_each_entry(p
, &tsk
->ptrace_children
,
1519 flag
= eligible_child(type
, pid
, options
, p
);
1522 if (likely(flag
> 0))
1528 if (options
& __WNOTHREAD
)
1530 tsk
= next_thread(tsk
);
1531 BUG_ON(tsk
->signal
!= current
->signal
);
1532 } while (tsk
!= current
);
1533 read_unlock(&tasklist_lock
);
1536 if (options
& WNOHANG
)
1538 retval
= -ERESTARTSYS
;
1539 if (signal_pending(current
))
1546 current
->state
= TASK_RUNNING
;
1547 remove_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1553 * For a WNOHANG return, clear out all the fields
1554 * we would set so the user can easily tell the
1558 retval
= put_user(0, &infop
->si_signo
);
1560 retval
= put_user(0, &infop
->si_errno
);
1562 retval
= put_user(0, &infop
->si_code
);
1564 retval
= put_user(0, &infop
->si_pid
);
1566 retval
= put_user(0, &infop
->si_uid
);
1568 retval
= put_user(0, &infop
->si_status
);
1574 asmlinkage
long sys_waitid(int which
, pid_t upid
,
1575 struct siginfo __user
*infop
, int options
,
1576 struct rusage __user
*ru
)
1578 struct pid
*pid
= NULL
;
1582 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1584 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1597 type
= PIDTYPE_PGID
;
1605 if (type
< PIDTYPE_MAX
)
1606 pid
= find_get_pid(upid
);
1607 ret
= do_wait(type
, pid
, options
, infop
, NULL
, ru
);
1610 /* avoid REGPARM breakage on x86: */
1611 prevent_tail_call(ret
);
1615 asmlinkage
long sys_wait4(pid_t upid
, int __user
*stat_addr
,
1616 int options
, struct rusage __user
*ru
)
1618 struct pid
*pid
= NULL
;
1622 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1623 __WNOTHREAD
|__WCLONE
|__WALL
))
1628 else if (upid
< 0) {
1629 type
= PIDTYPE_PGID
;
1630 pid
= find_get_pid(-upid
);
1631 } else if (upid
== 0) {
1632 type
= PIDTYPE_PGID
;
1633 pid
= get_pid(task_pgrp(current
));
1634 } else /* upid > 0 */ {
1636 pid
= find_get_pid(upid
);
1639 ret
= do_wait(type
, pid
, options
| WEXITED
, NULL
, stat_addr
, ru
);
1642 /* avoid REGPARM breakage on x86: */
1643 prevent_tail_call(ret
);
1647 #ifdef __ARCH_WANT_SYS_WAITPID
1650 * sys_waitpid() remains for compatibility. waitpid() should be
1651 * implemented by calling sys_wait4() from libc.a.
1653 asmlinkage
long sys_waitpid(pid_t pid
, int __user
*stat_addr
, int options
)
1655 return sys_wait4(pid
, stat_addr
, options
, NULL
);