4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/config.h>
9 #include <linux/slab.h>
10 #include <linux/interrupt.h>
11 #include <linux/smp_lock.h>
12 #include <linux/module.h>
13 #include <linux/capability.h>
14 #include <linux/completion.h>
15 #include <linux/personality.h>
16 #include <linux/tty.h>
17 #include <linux/namespace.h>
18 #include <linux/key.h>
19 #include <linux/security.h>
20 #include <linux/cpu.h>
21 #include <linux/acct.h>
22 #include <linux/file.h>
23 #include <linux/binfmts.h>
24 #include <linux/ptrace.h>
25 #include <linux/profile.h>
26 #include <linux/mount.h>
27 #include <linux/proc_fs.h>
28 #include <linux/mempolicy.h>
29 #include <linux/cpuset.h>
30 #include <linux/syscalls.h>
31 #include <linux/signal.h>
32 #include <linux/posix-timers.h>
33 #include <linux/cn_proc.h>
34 #include <linux/mutex.h>
35 #include <linux/futex.h>
36 #include <linux/compat.h>
37 #include <linux/pipe_fs_i.h>
38 #include <linux/audit.h> /* for audit_free() */
39 #include <linux/resource.h>
41 #include <asm/uaccess.h>
42 #include <asm/unistd.h>
43 #include <asm/pgtable.h>
44 #include <asm/mmu_context.h>
46 extern void sem_exit (void);
47 extern struct task_struct
*child_reaper
;
49 static void exit_mm(struct task_struct
* tsk
);
51 static void __unhash_process(struct task_struct
*p
)
54 detach_pid(p
, PIDTYPE_PID
);
55 if (thread_group_leader(p
)) {
56 detach_pid(p
, PIDTYPE_PGID
);
57 detach_pid(p
, PIDTYPE_SID
);
59 list_del_rcu(&p
->tasks
);
60 __get_cpu_var(process_counts
)--;
62 list_del_rcu(&p
->thread_group
);
67 * This function expects the tasklist_lock write-locked.
69 static void __exit_signal(struct task_struct
*tsk
)
71 struct signal_struct
*sig
= tsk
->signal
;
72 struct sighand_struct
*sighand
;
75 BUG_ON(!atomic_read(&sig
->count
));
78 sighand
= rcu_dereference(tsk
->sighand
);
79 spin_lock(&sighand
->siglock
);
81 posix_cpu_timers_exit(tsk
);
82 if (atomic_dec_and_test(&sig
->count
))
83 posix_cpu_timers_exit_group(tsk
);
86 * If there is any task waiting for the group exit
89 if (sig
->group_exit_task
&& atomic_read(&sig
->count
) == sig
->notify_count
) {
90 wake_up_process(sig
->group_exit_task
);
91 sig
->group_exit_task
= NULL
;
93 if (tsk
== sig
->curr_target
)
94 sig
->curr_target
= next_thread(tsk
);
96 * Accumulate here the counters for all threads but the
97 * group leader as they die, so they can be added into
98 * the process-wide totals when those are taken.
99 * The group leader stays around as a zombie as long
100 * as there are other threads. When it gets reaped,
101 * the exit.c code will add its counts into these totals.
102 * We won't ever get here for the group leader, since it
103 * will have been the last reference on the signal_struct.
105 sig
->utime
= cputime_add(sig
->utime
, tsk
->utime
);
106 sig
->stime
= cputime_add(sig
->stime
, tsk
->stime
);
107 sig
->min_flt
+= tsk
->min_flt
;
108 sig
->maj_flt
+= tsk
->maj_flt
;
109 sig
->nvcsw
+= tsk
->nvcsw
;
110 sig
->nivcsw
+= tsk
->nivcsw
;
111 sig
->sched_time
+= tsk
->sched_time
;
112 sig
= NULL
; /* Marker for below. */
115 __unhash_process(tsk
);
119 spin_unlock(&sighand
->siglock
);
122 __cleanup_sighand(sighand
);
123 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
124 flush_sigqueue(&tsk
->pending
);
126 flush_sigqueue(&sig
->shared_pending
);
127 __cleanup_signal(sig
);
131 static void delayed_put_task_struct(struct rcu_head
*rhp
)
133 put_task_struct(container_of(rhp
, struct task_struct
, rcu
));
136 void release_task(struct task_struct
* p
)
141 atomic_dec(&p
->user
->processes
);
142 write_lock_irq(&tasklist_lock
);
144 BUG_ON(!list_empty(&p
->ptrace_list
) || !list_empty(&p
->ptrace_children
));
148 * If we are the last non-leader member of the thread
149 * group, and the leader is zombie, then notify the
150 * group leader's parent process. (if it wants notification.)
153 leader
= p
->group_leader
;
154 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
155 BUG_ON(leader
->exit_signal
== -1);
156 do_notify_parent(leader
, leader
->exit_signal
);
158 * If we were the last child thread and the leader has
159 * exited already, and the leader's parent ignores SIGCHLD,
160 * then we are the one who should release the leader.
162 * do_notify_parent() will have marked it self-reaping in
165 zap_leader
= (leader
->exit_signal
== -1);
169 write_unlock_irq(&tasklist_lock
);
172 call_rcu(&p
->rcu
, delayed_put_task_struct
);
175 if (unlikely(zap_leader
))
180 * This checks not only the pgrp, but falls back on the pid if no
181 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
184 int session_of_pgrp(int pgrp
)
186 struct task_struct
*p
;
189 read_lock(&tasklist_lock
);
190 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
191 if (p
->signal
->session
> 0) {
192 sid
= p
->signal
->session
;
195 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
196 p
= find_task_by_pid(pgrp
);
198 sid
= p
->signal
->session
;
200 read_unlock(&tasklist_lock
);
206 * Determine if a process group is "orphaned", according to the POSIX
207 * definition in 2.2.2.52. Orphaned process groups are not to be affected
208 * by terminal-generated stop signals. Newly orphaned process groups are
209 * to receive a SIGHUP and a SIGCONT.
211 * "I ask you, have you ever known what it is to be an orphan?"
213 static int will_become_orphaned_pgrp(int pgrp
, task_t
*ignored_task
)
215 struct task_struct
*p
;
218 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
219 if (p
== ignored_task
221 || p
->real_parent
->pid
== 1)
223 if (process_group(p
->real_parent
) != pgrp
224 && p
->real_parent
->signal
->session
== p
->signal
->session
) {
228 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
229 return ret
; /* (sighing) "Often!" */
232 int is_orphaned_pgrp(int pgrp
)
236 read_lock(&tasklist_lock
);
237 retval
= will_become_orphaned_pgrp(pgrp
, NULL
);
238 read_unlock(&tasklist_lock
);
243 static int has_stopped_jobs(int pgrp
)
246 struct task_struct
*p
;
248 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
249 if (p
->state
!= TASK_STOPPED
)
252 /* If p is stopped by a debugger on a signal that won't
253 stop it, then don't count p as stopped. This isn't
254 perfect but it's a good approximation. */
255 if (unlikely (p
->ptrace
)
256 && p
->exit_code
!= SIGSTOP
257 && p
->exit_code
!= SIGTSTP
258 && p
->exit_code
!= SIGTTOU
259 && p
->exit_code
!= SIGTTIN
)
264 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
269 * reparent_to_init - Reparent the calling kernel thread to the init task.
271 * If a kernel thread is launched as a result of a system call, or if
272 * it ever exits, it should generally reparent itself to init so that
273 * it is correctly cleaned up on exit.
275 * The various task state such as scheduling policy and priority may have
276 * been inherited from a user process, so we reset them to sane values here.
278 * NOTE that reparent_to_init() gives the caller full capabilities.
280 static void reparent_to_init(void)
282 write_lock_irq(&tasklist_lock
);
284 ptrace_unlink(current
);
285 /* Reparent to init */
286 remove_parent(current
);
287 current
->parent
= child_reaper
;
288 current
->real_parent
= child_reaper
;
291 /* Set the exit signal to SIGCHLD so we signal init on exit */
292 current
->exit_signal
= SIGCHLD
;
294 if ((current
->policy
== SCHED_NORMAL
||
295 current
->policy
== SCHED_BATCH
)
296 && (task_nice(current
) < 0))
297 set_user_nice(current
, 0);
301 security_task_reparent_to_init(current
);
302 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
303 sizeof(current
->signal
->rlim
));
304 atomic_inc(&(INIT_USER
->__count
));
305 write_unlock_irq(&tasklist_lock
);
306 switch_uid(INIT_USER
);
309 void __set_special_pids(pid_t session
, pid_t pgrp
)
311 struct task_struct
*curr
= current
->group_leader
;
313 if (curr
->signal
->session
!= session
) {
314 detach_pid(curr
, PIDTYPE_SID
);
315 curr
->signal
->session
= session
;
316 attach_pid(curr
, PIDTYPE_SID
, session
);
318 if (process_group(curr
) != pgrp
) {
319 detach_pid(curr
, PIDTYPE_PGID
);
320 curr
->signal
->pgrp
= pgrp
;
321 attach_pid(curr
, PIDTYPE_PGID
, pgrp
);
325 void set_special_pids(pid_t session
, pid_t pgrp
)
327 write_lock_irq(&tasklist_lock
);
328 __set_special_pids(session
, pgrp
);
329 write_unlock_irq(&tasklist_lock
);
333 * Let kernel threads use this to say that they
334 * allow a certain signal (since daemonize() will
335 * have disabled all of them by default).
337 int allow_signal(int sig
)
339 if (!valid_signal(sig
) || sig
< 1)
342 spin_lock_irq(¤t
->sighand
->siglock
);
343 sigdelset(¤t
->blocked
, sig
);
345 /* Kernel threads handle their own signals.
346 Let the signal code know it'll be handled, so
347 that they don't get converted to SIGKILL or
348 just silently dropped */
349 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
352 spin_unlock_irq(¤t
->sighand
->siglock
);
356 EXPORT_SYMBOL(allow_signal
);
358 int disallow_signal(int sig
)
360 if (!valid_signal(sig
) || sig
< 1)
363 spin_lock_irq(¤t
->sighand
->siglock
);
364 sigaddset(¤t
->blocked
, sig
);
366 spin_unlock_irq(¤t
->sighand
->siglock
);
370 EXPORT_SYMBOL(disallow_signal
);
373 * Put all the gunge required to become a kernel thread without
374 * attached user resources in one place where it belongs.
377 void daemonize(const char *name
, ...)
380 struct fs_struct
*fs
;
383 va_start(args
, name
);
384 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
388 * If we were started as result of loading a module, close all of the
389 * user space pages. We don't need them, and if we didn't close them
390 * they would be locked into memory.
394 set_special_pids(1, 1);
395 mutex_lock(&tty_mutex
);
396 current
->signal
->tty
= NULL
;
397 mutex_unlock(&tty_mutex
);
399 /* Block and flush all signals */
400 sigfillset(&blocked
);
401 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
402 flush_signals(current
);
404 /* Become as one with the init task */
406 exit_fs(current
); /* current->fs->count--; */
409 atomic_inc(&fs
->count
);
410 exit_namespace(current
);
411 current
->namespace = init_task
.namespace;
412 get_namespace(current
->namespace);
414 current
->files
= init_task
.files
;
415 atomic_inc(¤t
->files
->count
);
420 EXPORT_SYMBOL(daemonize
);
422 static void close_files(struct files_struct
* files
)
430 * It is safe to dereference the fd table without RCU or
431 * ->file_lock because this is the last reference to the
434 fdt
= files_fdtable(files
);
438 if (i
>= fdt
->max_fdset
|| i
>= fdt
->max_fds
)
440 set
= fdt
->open_fds
->fds_bits
[j
++];
443 struct file
* file
= xchg(&fdt
->fd
[i
], NULL
);
445 filp_close(file
, files
);
453 struct files_struct
*get_files_struct(struct task_struct
*task
)
455 struct files_struct
*files
;
460 atomic_inc(&files
->count
);
466 void fastcall
put_files_struct(struct files_struct
*files
)
470 if (atomic_dec_and_test(&files
->count
)) {
473 * Free the fd and fdset arrays if we expanded them.
474 * If the fdtable was embedded, pass files for freeing
475 * at the end of the RCU grace period. Otherwise,
476 * you can free files immediately.
478 fdt
= files_fdtable(files
);
479 if (fdt
== &files
->fdtab
)
480 fdt
->free_files
= files
;
482 kmem_cache_free(files_cachep
, files
);
487 EXPORT_SYMBOL(put_files_struct
);
489 static inline void __exit_files(struct task_struct
*tsk
)
491 struct files_struct
* files
= tsk
->files
;
497 put_files_struct(files
);
501 void exit_files(struct task_struct
*tsk
)
506 static inline void __put_fs_struct(struct fs_struct
*fs
)
508 /* No need to hold fs->lock if we are killing it */
509 if (atomic_dec_and_test(&fs
->count
)) {
516 mntput(fs
->altrootmnt
);
518 kmem_cache_free(fs_cachep
, fs
);
522 void put_fs_struct(struct fs_struct
*fs
)
527 static inline void __exit_fs(struct task_struct
*tsk
)
529 struct fs_struct
* fs
= tsk
->fs
;
539 void exit_fs(struct task_struct
*tsk
)
544 EXPORT_SYMBOL_GPL(exit_fs
);
547 * Turn us into a lazy TLB process if we
550 static void exit_mm(struct task_struct
* tsk
)
552 struct mm_struct
*mm
= tsk
->mm
;
558 * Serialize with any possible pending coredump.
559 * We must hold mmap_sem around checking core_waiters
560 * and clearing tsk->mm. The core-inducing thread
561 * will increment core_waiters for each thread in the
562 * group with ->mm != NULL.
564 down_read(&mm
->mmap_sem
);
565 if (mm
->core_waiters
) {
566 up_read(&mm
->mmap_sem
);
567 down_write(&mm
->mmap_sem
);
568 if (!--mm
->core_waiters
)
569 complete(mm
->core_startup_done
);
570 up_write(&mm
->mmap_sem
);
572 wait_for_completion(&mm
->core_done
);
573 down_read(&mm
->mmap_sem
);
575 atomic_inc(&mm
->mm_count
);
576 BUG_ON(mm
!= tsk
->active_mm
);
577 /* more a memory barrier than a real lock */
580 up_read(&mm
->mmap_sem
);
581 enter_lazy_tlb(mm
, current
);
586 static inline void choose_new_parent(task_t
*p
, task_t
*reaper
)
589 * Make sure we're not reparenting to ourselves and that
590 * the parent is not a zombie.
592 BUG_ON(p
== reaper
|| reaper
->exit_state
);
593 p
->real_parent
= reaper
;
596 static void reparent_thread(task_t
*p
, task_t
*father
, int traced
)
598 /* We don't want people slaying init. */
599 if (p
->exit_signal
!= -1)
600 p
->exit_signal
= SIGCHLD
;
602 if (p
->pdeath_signal
)
603 /* We already hold the tasklist_lock here. */
604 group_send_sig_info(p
->pdeath_signal
, SEND_SIG_NOINFO
, p
);
606 /* Move the child from its dying parent to the new one. */
607 if (unlikely(traced
)) {
608 /* Preserve ptrace links if someone else is tracing this child. */
609 list_del_init(&p
->ptrace_list
);
610 if (p
->parent
!= p
->real_parent
)
611 list_add(&p
->ptrace_list
, &p
->real_parent
->ptrace_children
);
613 /* If this child is being traced, then we're the one tracing it
614 * anyway, so let go of it.
618 p
->parent
= p
->real_parent
;
621 /* If we'd notified the old parent about this child's death,
622 * also notify the new parent.
624 if (p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
!= -1 &&
625 thread_group_empty(p
))
626 do_notify_parent(p
, p
->exit_signal
);
627 else if (p
->state
== TASK_TRACED
) {
629 * If it was at a trace stop, turn it into
630 * a normal stop since it's no longer being
638 * process group orphan check
639 * Case ii: Our child is in a different pgrp
640 * than we are, and it was the only connection
641 * outside, so the child pgrp is now orphaned.
643 if ((process_group(p
) != process_group(father
)) &&
644 (p
->signal
->session
== father
->signal
->session
)) {
645 int pgrp
= process_group(p
);
647 if (will_become_orphaned_pgrp(pgrp
, NULL
) && has_stopped_jobs(pgrp
)) {
648 __kill_pg_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
649 __kill_pg_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
655 * When we die, we re-parent all our children.
656 * Try to give them to another thread in our thread
657 * group, and if no such member exists, give it to
658 * the global child reaper process (ie "init")
660 static void forget_original_parent(struct task_struct
* father
,
661 struct list_head
*to_release
)
663 struct task_struct
*p
, *reaper
= father
;
664 struct list_head
*_p
, *_n
;
667 reaper
= next_thread(reaper
);
668 if (reaper
== father
) {
669 reaper
= child_reaper
;
672 } while (reaper
->exit_state
);
675 * There are only two places where our children can be:
677 * - in our child list
678 * - in our ptraced child list
680 * Search them and reparent children.
682 list_for_each_safe(_p
, _n
, &father
->children
) {
684 p
= list_entry(_p
,struct task_struct
,sibling
);
688 /* if father isn't the real parent, then ptrace must be enabled */
689 BUG_ON(father
!= p
->real_parent
&& !ptrace
);
691 if (father
== p
->real_parent
) {
692 /* reparent with a reaper, real father it's us */
693 choose_new_parent(p
, reaper
);
694 reparent_thread(p
, father
, 0);
696 /* reparent ptraced task to its real parent */
698 if (p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
!= -1 &&
699 thread_group_empty(p
))
700 do_notify_parent(p
, p
->exit_signal
);
704 * if the ptraced child is a zombie with exit_signal == -1
705 * we must collect it before we exit, or it will remain
706 * zombie forever since we prevented it from self-reap itself
707 * while it was being traced by us, to be able to see it in wait4.
709 if (unlikely(ptrace
&& p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
== -1))
710 list_add(&p
->ptrace_list
, to_release
);
712 list_for_each_safe(_p
, _n
, &father
->ptrace_children
) {
713 p
= list_entry(_p
,struct task_struct
,ptrace_list
);
714 choose_new_parent(p
, reaper
);
715 reparent_thread(p
, father
, 1);
720 * Send signals to all our closest relatives so that they know
721 * to properly mourn us..
723 static void exit_notify(struct task_struct
*tsk
)
726 struct task_struct
*t
;
727 struct list_head ptrace_dead
, *_p
, *_n
;
729 if (signal_pending(tsk
) && !(tsk
->signal
->flags
& SIGNAL_GROUP_EXIT
)
730 && !thread_group_empty(tsk
)) {
732 * This occurs when there was a race between our exit
733 * syscall and a group signal choosing us as the one to
734 * wake up. It could be that we are the only thread
735 * alerted to check for pending signals, but another thread
736 * should be woken now to take the signal since we will not.
737 * Now we'll wake all the threads in the group just to make
738 * sure someone gets all the pending signals.
740 read_lock(&tasklist_lock
);
741 spin_lock_irq(&tsk
->sighand
->siglock
);
742 for (t
= next_thread(tsk
); t
!= tsk
; t
= next_thread(t
))
743 if (!signal_pending(t
) && !(t
->flags
& PF_EXITING
)) {
744 recalc_sigpending_tsk(t
);
745 if (signal_pending(t
))
746 signal_wake_up(t
, 0);
748 spin_unlock_irq(&tsk
->sighand
->siglock
);
749 read_unlock(&tasklist_lock
);
752 write_lock_irq(&tasklist_lock
);
755 * This does two things:
757 * A. Make init inherit all the child processes
758 * B. Check to see if any process groups have become orphaned
759 * as a result of our exiting, and if they have any stopped
760 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
763 INIT_LIST_HEAD(&ptrace_dead
);
764 forget_original_parent(tsk
, &ptrace_dead
);
765 BUG_ON(!list_empty(&tsk
->children
));
766 BUG_ON(!list_empty(&tsk
->ptrace_children
));
769 * Check to see if any process groups have become orphaned
770 * as a result of our exiting, and if they have any stopped
771 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
773 * Case i: Our father is in a different pgrp than we are
774 * and we were the only connection outside, so our pgrp
775 * is about to become orphaned.
778 t
= tsk
->real_parent
;
780 if ((process_group(t
) != process_group(tsk
)) &&
781 (t
->signal
->session
== tsk
->signal
->session
) &&
782 will_become_orphaned_pgrp(process_group(tsk
), tsk
) &&
783 has_stopped_jobs(process_group(tsk
))) {
784 __kill_pg_info(SIGHUP
, SEND_SIG_PRIV
, process_group(tsk
));
785 __kill_pg_info(SIGCONT
, SEND_SIG_PRIV
, process_group(tsk
));
788 /* Let father know we died
790 * Thread signals are configurable, but you aren't going to use
791 * that to send signals to arbitary processes.
792 * That stops right now.
794 * If the parent exec id doesn't match the exec id we saved
795 * when we started then we know the parent has changed security
798 * If our self_exec id doesn't match our parent_exec_id then
799 * we have changed execution domain as these two values started
800 * the same after a fork.
804 if (tsk
->exit_signal
!= SIGCHLD
&& tsk
->exit_signal
!= -1 &&
805 ( tsk
->parent_exec_id
!= t
->self_exec_id
||
806 tsk
->self_exec_id
!= tsk
->parent_exec_id
)
807 && !capable(CAP_KILL
))
808 tsk
->exit_signal
= SIGCHLD
;
811 /* If something other than our normal parent is ptracing us, then
812 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
813 * only has special meaning to our real parent.
815 if (tsk
->exit_signal
!= -1 && thread_group_empty(tsk
)) {
816 int signal
= tsk
->parent
== tsk
->real_parent
? tsk
->exit_signal
: SIGCHLD
;
817 do_notify_parent(tsk
, signal
);
818 } else if (tsk
->ptrace
) {
819 do_notify_parent(tsk
, SIGCHLD
);
823 if (tsk
->exit_signal
== -1 &&
824 (likely(tsk
->ptrace
== 0) ||
825 unlikely(tsk
->parent
->signal
->flags
& SIGNAL_GROUP_EXIT
)))
827 tsk
->exit_state
= state
;
829 write_unlock_irq(&tasklist_lock
);
831 list_for_each_safe(_p
, _n
, &ptrace_dead
) {
833 t
= list_entry(_p
,struct task_struct
,ptrace_list
);
837 /* If the process is dead, release it - nobody will wait for it */
838 if (state
== EXIT_DEAD
)
842 fastcall NORET_TYPE
void do_exit(long code
)
844 struct task_struct
*tsk
= current
;
847 profile_task_exit(tsk
);
849 WARN_ON(atomic_read(&tsk
->fs_excl
));
851 if (unlikely(in_interrupt()))
852 panic("Aiee, killing interrupt handler!");
853 if (unlikely(!tsk
->pid
))
854 panic("Attempted to kill the idle task!");
855 if (unlikely(tsk
== child_reaper
))
856 panic("Attempted to kill init!");
858 if (unlikely(current
->ptrace
& PT_TRACE_EXIT
)) {
859 current
->ptrace_message
= code
;
860 ptrace_notify((PTRACE_EVENT_EXIT
<< 8) | SIGTRAP
);
864 * We're taking recursive faults here in do_exit. Safest is to just
865 * leave this task alone and wait for reboot.
867 if (unlikely(tsk
->flags
& PF_EXITING
)) {
869 "Fixing recursive fault but reboot is needed!\n");
872 set_current_state(TASK_UNINTERRUPTIBLE
);
876 tsk
->flags
|= PF_EXITING
;
878 if (unlikely(in_atomic()))
879 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
880 current
->comm
, current
->pid
,
883 acct_update_integrals(tsk
);
885 update_hiwater_rss(tsk
->mm
);
886 update_hiwater_vm(tsk
->mm
);
888 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
890 hrtimer_cancel(&tsk
->signal
->real_timer
);
891 exit_itimers(tsk
->signal
);
893 acct_collect(code
, group_dead
);
894 if (unlikely(tsk
->robust_list
))
895 exit_robust_list(tsk
);
896 #if defined(CONFIG_FUTEX) && defined(CONFIG_COMPAT)
897 if (unlikely(tsk
->compat_robust_list
))
898 compat_exit_robust_list(tsk
);
900 if (unlikely(tsk
->audit_context
))
914 if (group_dead
&& tsk
->signal
->leader
)
915 disassociate_ctty(1);
917 module_put(task_thread_info(tsk
)->exec_domain
->module
);
919 module_put(tsk
->binfmt
->module
);
921 tsk
->exit_code
= code
;
922 proc_exit_connector(tsk
);
925 mpol_free(tsk
->mempolicy
);
926 tsk
->mempolicy
= NULL
;
929 * If DEBUG_MUTEXES is on, make sure we are holding no locks:
931 mutex_debug_check_no_locks_held(tsk
);
936 if (tsk
->splice_pipe
)
937 __free_pipe_info(tsk
->splice_pipe
);
939 /* PF_DEAD causes final put_task_struct after we schedule. */
941 BUG_ON(tsk
->flags
& PF_DEAD
);
942 tsk
->flags
|= PF_DEAD
;
946 /* Avoid "noreturn function does return". */
950 EXPORT_SYMBOL_GPL(do_exit
);
952 NORET_TYPE
void complete_and_exit(struct completion
*comp
, long code
)
960 EXPORT_SYMBOL(complete_and_exit
);
962 asmlinkage
long sys_exit(int error_code
)
964 do_exit((error_code
&0xff)<<8);
968 * Take down every thread in the group. This is called by fatal signals
969 * as well as by sys_exit_group (below).
972 do_group_exit(int exit_code
)
974 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
976 if (current
->signal
->flags
& SIGNAL_GROUP_EXIT
)
977 exit_code
= current
->signal
->group_exit_code
;
978 else if (!thread_group_empty(current
)) {
979 struct signal_struct
*const sig
= current
->signal
;
980 struct sighand_struct
*const sighand
= current
->sighand
;
981 spin_lock_irq(&sighand
->siglock
);
982 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
983 /* Another thread got here before we took the lock. */
984 exit_code
= sig
->group_exit_code
;
986 sig
->group_exit_code
= exit_code
;
987 zap_other_threads(current
);
989 spin_unlock_irq(&sighand
->siglock
);
997 * this kills every thread in the thread group. Note that any externally
998 * wait4()-ing process will get the correct exit code - even if this
999 * thread is not the thread group leader.
1001 asmlinkage
void sys_exit_group(int error_code
)
1003 do_group_exit((error_code
& 0xff) << 8);
1006 static int eligible_child(pid_t pid
, int options
, task_t
*p
)
1012 if (process_group(p
) != process_group(current
))
1014 } else if (pid
!= -1) {
1015 if (process_group(p
) != -pid
)
1020 * Do not consider detached threads that are
1023 if (p
->exit_signal
== -1 && !p
->ptrace
)
1026 /* Wait for all children (clone and not) if __WALL is set;
1027 * otherwise, wait for clone children *only* if __WCLONE is
1028 * set; otherwise, wait for non-clone children *only*. (Note:
1029 * A "clone" child here is one that reports to its parent
1030 * using a signal other than SIGCHLD.) */
1031 if (((p
->exit_signal
!= SIGCHLD
) ^ ((options
& __WCLONE
) != 0))
1032 && !(options
& __WALL
))
1035 * Do not consider thread group leaders that are
1036 * in a non-empty thread group:
1038 if (current
->tgid
!= p
->tgid
&& delay_group_leader(p
))
1041 if (security_task_wait(p
))
1047 static int wait_noreap_copyout(task_t
*p
, pid_t pid
, uid_t uid
,
1048 int why
, int status
,
1049 struct siginfo __user
*infop
,
1050 struct rusage __user
*rusagep
)
1052 int retval
= rusagep
? getrusage(p
, RUSAGE_BOTH
, rusagep
) : 0;
1055 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1057 retval
= put_user(0, &infop
->si_errno
);
1059 retval
= put_user((short)why
, &infop
->si_code
);
1061 retval
= put_user(pid
, &infop
->si_pid
);
1063 retval
= put_user(uid
, &infop
->si_uid
);
1065 retval
= put_user(status
, &infop
->si_status
);
1072 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1073 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1074 * the lock and this task is uninteresting. If we return nonzero, we have
1075 * released the lock and the system call should return.
1077 static int wait_task_zombie(task_t
*p
, int noreap
,
1078 struct siginfo __user
*infop
,
1079 int __user
*stat_addr
, struct rusage __user
*ru
)
1081 unsigned long state
;
1085 if (unlikely(noreap
)) {
1088 int exit_code
= p
->exit_code
;
1091 if (unlikely(p
->exit_state
!= EXIT_ZOMBIE
))
1093 if (unlikely(p
->exit_signal
== -1 && p
->ptrace
== 0))
1096 read_unlock(&tasklist_lock
);
1097 if ((exit_code
& 0x7f) == 0) {
1099 status
= exit_code
>> 8;
1101 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1102 status
= exit_code
& 0x7f;
1104 return wait_noreap_copyout(p
, pid
, uid
, why
,
1109 * Try to move the task's state to DEAD
1110 * only one thread is allowed to do this:
1112 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1113 if (state
!= EXIT_ZOMBIE
) {
1114 BUG_ON(state
!= EXIT_DEAD
);
1117 if (unlikely(p
->exit_signal
== -1 && p
->ptrace
== 0)) {
1119 * This can only happen in a race with a ptraced thread
1120 * dying on another processor.
1125 if (likely(p
->real_parent
== p
->parent
) && likely(p
->signal
)) {
1126 struct signal_struct
*psig
;
1127 struct signal_struct
*sig
;
1130 * The resource counters for the group leader are in its
1131 * own task_struct. Those for dead threads in the group
1132 * are in its signal_struct, as are those for the child
1133 * processes it has previously reaped. All these
1134 * accumulate in the parent's signal_struct c* fields.
1136 * We don't bother to take a lock here to protect these
1137 * p->signal fields, because they are only touched by
1138 * __exit_signal, which runs with tasklist_lock
1139 * write-locked anyway, and so is excluded here. We do
1140 * need to protect the access to p->parent->signal fields,
1141 * as other threads in the parent group can be right
1142 * here reaping other children at the same time.
1144 spin_lock_irq(&p
->parent
->sighand
->siglock
);
1145 psig
= p
->parent
->signal
;
1148 cputime_add(psig
->cutime
,
1149 cputime_add(p
->utime
,
1150 cputime_add(sig
->utime
,
1153 cputime_add(psig
->cstime
,
1154 cputime_add(p
->stime
,
1155 cputime_add(sig
->stime
,
1158 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1160 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1162 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1164 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1165 spin_unlock_irq(&p
->parent
->sighand
->siglock
);
1169 * Now we are sure this task is interesting, and no other
1170 * thread can reap it because we set its state to EXIT_DEAD.
1172 read_unlock(&tasklist_lock
);
1174 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1175 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1176 ? p
->signal
->group_exit_code
: p
->exit_code
;
1177 if (!retval
&& stat_addr
)
1178 retval
= put_user(status
, stat_addr
);
1179 if (!retval
&& infop
)
1180 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1181 if (!retval
&& infop
)
1182 retval
= put_user(0, &infop
->si_errno
);
1183 if (!retval
&& infop
) {
1186 if ((status
& 0x7f) == 0) {
1190 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1193 retval
= put_user((short)why
, &infop
->si_code
);
1195 retval
= put_user(status
, &infop
->si_status
);
1197 if (!retval
&& infop
)
1198 retval
= put_user(p
->pid
, &infop
->si_pid
);
1199 if (!retval
&& infop
)
1200 retval
= put_user(p
->uid
, &infop
->si_uid
);
1202 // TODO: is this safe?
1203 p
->exit_state
= EXIT_ZOMBIE
;
1207 if (p
->real_parent
!= p
->parent
) {
1208 write_lock_irq(&tasklist_lock
);
1209 /* Double-check with lock held. */
1210 if (p
->real_parent
!= p
->parent
) {
1212 // TODO: is this safe?
1213 p
->exit_state
= EXIT_ZOMBIE
;
1215 * If this is not a detached task, notify the parent.
1216 * If it's still not detached after that, don't release
1219 if (p
->exit_signal
!= -1) {
1220 do_notify_parent(p
, p
->exit_signal
);
1221 if (p
->exit_signal
!= -1)
1225 write_unlock_irq(&tasklist_lock
);
1234 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1235 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1236 * the lock and this task is uninteresting. If we return nonzero, we have
1237 * released the lock and the system call should return.
1239 static int wait_task_stopped(task_t
*p
, int delayed_group_leader
, int noreap
,
1240 struct siginfo __user
*infop
,
1241 int __user
*stat_addr
, struct rusage __user
*ru
)
1243 int retval
, exit_code
;
1247 if (delayed_group_leader
&& !(p
->ptrace
& PT_PTRACED
) &&
1248 p
->signal
&& p
->signal
->group_stop_count
> 0)
1250 * A group stop is in progress and this is the group leader.
1251 * We won't report until all threads have stopped.
1256 * Now we are pretty sure this task is interesting.
1257 * Make sure it doesn't get reaped out from under us while we
1258 * give up the lock and then examine it below. We don't want to
1259 * keep holding onto the tasklist_lock while we call getrusage and
1260 * possibly take page faults for user memory.
1263 read_unlock(&tasklist_lock
);
1265 if (unlikely(noreap
)) {
1268 int why
= (p
->ptrace
& PT_PTRACED
) ? CLD_TRAPPED
: CLD_STOPPED
;
1270 exit_code
= p
->exit_code
;
1271 if (unlikely(!exit_code
) ||
1272 unlikely(p
->state
& TASK_TRACED
))
1274 return wait_noreap_copyout(p
, pid
, uid
,
1275 why
, (exit_code
<< 8) | 0x7f,
1279 write_lock_irq(&tasklist_lock
);
1282 * This uses xchg to be atomic with the thread resuming and setting
1283 * it. It must also be done with the write lock held to prevent a
1284 * race with the EXIT_ZOMBIE case.
1286 exit_code
= xchg(&p
->exit_code
, 0);
1287 if (unlikely(p
->exit_state
)) {
1289 * The task resumed and then died. Let the next iteration
1290 * catch it in EXIT_ZOMBIE. Note that exit_code might
1291 * already be zero here if it resumed and did _exit(0).
1292 * The task itself is dead and won't touch exit_code again;
1293 * other processors in this function are locked out.
1295 p
->exit_code
= exit_code
;
1298 if (unlikely(exit_code
== 0)) {
1300 * Another thread in this function got to it first, or it
1301 * resumed, or it resumed and then died.
1303 write_unlock_irq(&tasklist_lock
);
1307 * We are returning to the wait loop without having successfully
1308 * removed the process and having released the lock. We cannot
1309 * continue, since the "p" task pointer is potentially stale.
1311 * Return -EAGAIN, and do_wait() will restart the loop from the
1312 * beginning. Do _not_ re-acquire the lock.
1317 /* move to end of parent's list to avoid starvation */
1321 write_unlock_irq(&tasklist_lock
);
1323 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1324 if (!retval
&& stat_addr
)
1325 retval
= put_user((exit_code
<< 8) | 0x7f, stat_addr
);
1326 if (!retval
&& infop
)
1327 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1328 if (!retval
&& infop
)
1329 retval
= put_user(0, &infop
->si_errno
);
1330 if (!retval
&& infop
)
1331 retval
= put_user((short)((p
->ptrace
& PT_PTRACED
)
1332 ? CLD_TRAPPED
: CLD_STOPPED
),
1334 if (!retval
&& infop
)
1335 retval
= put_user(exit_code
, &infop
->si_status
);
1336 if (!retval
&& infop
)
1337 retval
= put_user(p
->pid
, &infop
->si_pid
);
1338 if (!retval
&& infop
)
1339 retval
= put_user(p
->uid
, &infop
->si_uid
);
1349 * Handle do_wait work for one task in a live, non-stopped state.
1350 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1351 * the lock and this task is uninteresting. If we return nonzero, we have
1352 * released the lock and the system call should return.
1354 static int wait_task_continued(task_t
*p
, int noreap
,
1355 struct siginfo __user
*infop
,
1356 int __user
*stat_addr
, struct rusage __user
*ru
)
1362 if (unlikely(!p
->signal
))
1365 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1368 spin_lock_irq(&p
->sighand
->siglock
);
1369 /* Re-check with the lock held. */
1370 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1371 spin_unlock_irq(&p
->sighand
->siglock
);
1375 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1376 spin_unlock_irq(&p
->sighand
->siglock
);
1381 read_unlock(&tasklist_lock
);
1384 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1386 if (!retval
&& stat_addr
)
1387 retval
= put_user(0xffff, stat_addr
);
1391 retval
= wait_noreap_copyout(p
, pid
, uid
,
1392 CLD_CONTINUED
, SIGCONT
,
1394 BUG_ON(retval
== 0);
1401 static inline int my_ptrace_child(struct task_struct
*p
)
1403 if (!(p
->ptrace
& PT_PTRACED
))
1405 if (!(p
->ptrace
& PT_ATTACHED
))
1408 * This child was PTRACE_ATTACH'd. We should be seeing it only if
1409 * we are the attacher. If we are the real parent, this is a race
1410 * inside ptrace_attach. It is waiting for the tasklist_lock,
1411 * which we have to switch the parent links, but has already set
1412 * the flags in p->ptrace.
1414 return (p
->parent
!= p
->real_parent
);
1417 static long do_wait(pid_t pid
, int options
, struct siginfo __user
*infop
,
1418 int __user
*stat_addr
, struct rusage __user
*ru
)
1420 DECLARE_WAITQUEUE(wait
, current
);
1421 struct task_struct
*tsk
;
1424 add_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1427 * We will set this flag if we see any child that might later
1428 * match our criteria, even if we are not able to reap it yet.
1431 current
->state
= TASK_INTERRUPTIBLE
;
1432 read_lock(&tasklist_lock
);
1435 struct task_struct
*p
;
1436 struct list_head
*_p
;
1439 list_for_each(_p
,&tsk
->children
) {
1440 p
= list_entry(_p
,struct task_struct
,sibling
);
1442 ret
= eligible_child(pid
, options
, p
);
1449 * When we hit the race with PTRACE_ATTACH,
1450 * we will not report this child. But the
1451 * race means it has not yet been moved to
1452 * our ptrace_children list, so we need to
1453 * set the flag here to avoid a spurious ECHILD
1454 * when the race happens with the only child.
1457 if (!my_ptrace_child(p
))
1462 * It's stopped now, so it might later
1463 * continue, exit, or stop again.
1466 if (!(options
& WUNTRACED
) &&
1467 !my_ptrace_child(p
))
1469 retval
= wait_task_stopped(p
, ret
== 2,
1470 (options
& WNOWAIT
),
1473 if (retval
== -EAGAIN
)
1475 if (retval
!= 0) /* He released the lock. */
1480 if (p
->exit_state
== EXIT_DEAD
)
1482 // case EXIT_ZOMBIE:
1483 if (p
->exit_state
== EXIT_ZOMBIE
) {
1485 * Eligible but we cannot release
1489 goto check_continued
;
1490 if (!likely(options
& WEXITED
))
1492 retval
= wait_task_zombie(
1493 p
, (options
& WNOWAIT
),
1494 infop
, stat_addr
, ru
);
1495 /* He released the lock. */
1502 * It's running now, so it might later
1503 * exit, stop, or stop and then continue.
1506 if (!unlikely(options
& WCONTINUED
))
1508 retval
= wait_task_continued(
1509 p
, (options
& WNOWAIT
),
1510 infop
, stat_addr
, ru
);
1511 if (retval
!= 0) /* He released the lock. */
1517 list_for_each(_p
, &tsk
->ptrace_children
) {
1518 p
= list_entry(_p
, struct task_struct
,
1520 if (!eligible_child(pid
, options
, p
))
1526 if (options
& __WNOTHREAD
)
1528 tsk
= next_thread(tsk
);
1529 BUG_ON(tsk
->signal
!= current
->signal
);
1530 } while (tsk
!= current
);
1532 read_unlock(&tasklist_lock
);
1535 if (options
& WNOHANG
)
1537 retval
= -ERESTARTSYS
;
1538 if (signal_pending(current
))
1545 current
->state
= TASK_RUNNING
;
1546 remove_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1552 * For a WNOHANG return, clear out all the fields
1553 * we would set so the user can easily tell the
1557 retval
= put_user(0, &infop
->si_signo
);
1559 retval
= put_user(0, &infop
->si_errno
);
1561 retval
= put_user(0, &infop
->si_code
);
1563 retval
= put_user(0, &infop
->si_pid
);
1565 retval
= put_user(0, &infop
->si_uid
);
1567 retval
= put_user(0, &infop
->si_status
);
1573 asmlinkage
long sys_waitid(int which
, pid_t pid
,
1574 struct siginfo __user
*infop
, int options
,
1575 struct rusage __user
*ru
)
1579 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1581 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1601 ret
= do_wait(pid
, options
, infop
, NULL
, ru
);
1603 /* avoid REGPARM breakage on x86: */
1604 prevent_tail_call(ret
);
1608 asmlinkage
long sys_wait4(pid_t pid
, int __user
*stat_addr
,
1609 int options
, struct rusage __user
*ru
)
1613 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1614 __WNOTHREAD
|__WCLONE
|__WALL
))
1616 ret
= do_wait(pid
, options
| WEXITED
, NULL
, stat_addr
, ru
);
1618 /* avoid REGPARM breakage on x86: */
1619 prevent_tail_call(ret
);
1623 #ifdef __ARCH_WANT_SYS_WAITPID
1626 * sys_waitpid() remains for compatibility. waitpid() should be
1627 * implemented by calling sys_wait4() from libc.a.
1629 asmlinkage
long sys_waitpid(pid_t pid
, int __user
*stat_addr
, int options
)
1631 return sys_wait4(pid
, stat_addr
, options
, NULL
);