]>
git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - kernel/exit.c
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>
38 #include <asm/uaccess.h>
39 #include <asm/unistd.h>
40 #include <asm/pgtable.h>
41 #include <asm/mmu_context.h>
43 extern void sem_exit (void);
44 extern struct task_struct
*child_reaper
;
46 int getrusage(struct task_struct
*, int, struct rusage __user
*);
48 static void exit_mm(struct task_struct
* tsk
);
50 static void __unhash_process(struct task_struct
*p
)
53 detach_pid(p
, PIDTYPE_PID
);
54 detach_pid(p
, PIDTYPE_TGID
);
55 if (thread_group_leader(p
)) {
56 detach_pid(p
, PIDTYPE_PGID
);
57 detach_pid(p
, PIDTYPE_SID
);
59 list_del_init(&p
->tasks
);
60 __get_cpu_var(process_counts
)--;
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. */
116 cleanup_sighand(tsk
);
117 spin_unlock(&sighand
->siglock
);
120 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
121 flush_sigqueue(&tsk
->pending
);
123 flush_sigqueue(&sig
->shared_pending
);
124 __cleanup_signal(sig
);
128 void release_task(struct task_struct
* p
)
132 struct dentry
*proc_dentry
;
135 atomic_dec(&p
->user
->processes
);
136 spin_lock(&p
->proc_lock
);
137 proc_dentry
= proc_pid_unhash(p
);
138 write_lock_irq(&tasklist_lock
);
140 BUG_ON(!list_empty(&p
->ptrace_list
) || !list_empty(&p
->ptrace_children
));
143 * Note that the fastpath in sys_times depends on __exit_signal having
144 * updated the counters before a task is removed from the tasklist of
145 * the process by __unhash_process.
150 * If we are the last non-leader member of the thread
151 * group, and the leader is zombie, then notify the
152 * group leader's parent process. (if it wants notification.)
155 leader
= p
->group_leader
;
156 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
157 BUG_ON(leader
->exit_signal
== -1);
158 do_notify_parent(leader
, leader
->exit_signal
);
160 * If we were the last child thread and the leader has
161 * exited already, and the leader's parent ignores SIGCHLD,
162 * then we are the one who should release the leader.
164 * do_notify_parent() will have marked it self-reaping in
167 zap_leader
= (leader
->exit_signal
== -1);
171 write_unlock_irq(&tasklist_lock
);
172 spin_unlock(&p
->proc_lock
);
173 proc_pid_flush(proc_dentry
);
178 if (unlikely(zap_leader
))
183 * This checks not only the pgrp, but falls back on the pid if no
184 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
187 int session_of_pgrp(int pgrp
)
189 struct task_struct
*p
;
192 read_lock(&tasklist_lock
);
193 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
194 if (p
->signal
->session
> 0) {
195 sid
= p
->signal
->session
;
198 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
199 p
= find_task_by_pid(pgrp
);
201 sid
= p
->signal
->session
;
203 read_unlock(&tasklist_lock
);
209 * Determine if a process group is "orphaned", according to the POSIX
210 * definition in 2.2.2.52. Orphaned process groups are not to be affected
211 * by terminal-generated stop signals. Newly orphaned process groups are
212 * to receive a SIGHUP and a SIGCONT.
214 * "I ask you, have you ever known what it is to be an orphan?"
216 static int will_become_orphaned_pgrp(int pgrp
, task_t
*ignored_task
)
218 struct task_struct
*p
;
221 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
222 if (p
== ignored_task
224 || p
->real_parent
->pid
== 1)
226 if (process_group(p
->real_parent
) != pgrp
227 && p
->real_parent
->signal
->session
== p
->signal
->session
) {
231 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
232 return ret
; /* (sighing) "Often!" */
235 int is_orphaned_pgrp(int pgrp
)
239 read_lock(&tasklist_lock
);
240 retval
= will_become_orphaned_pgrp(pgrp
, NULL
);
241 read_unlock(&tasklist_lock
);
246 static int has_stopped_jobs(int pgrp
)
249 struct task_struct
*p
;
251 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
252 if (p
->state
!= TASK_STOPPED
)
255 /* If p is stopped by a debugger on a signal that won't
256 stop it, then don't count p as stopped. This isn't
257 perfect but it's a good approximation. */
258 if (unlikely (p
->ptrace
)
259 && p
->exit_code
!= SIGSTOP
260 && p
->exit_code
!= SIGTSTP
261 && p
->exit_code
!= SIGTTOU
262 && p
->exit_code
!= SIGTTIN
)
267 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
272 * reparent_to_init - Reparent the calling kernel thread to the init task.
274 * If a kernel thread is launched as a result of a system call, or if
275 * it ever exits, it should generally reparent itself to init so that
276 * it is correctly cleaned up on exit.
278 * The various task state such as scheduling policy and priority may have
279 * been inherited from a user process, so we reset them to sane values here.
281 * NOTE that reparent_to_init() gives the caller full capabilities.
283 static void reparent_to_init(void)
285 write_lock_irq(&tasklist_lock
);
287 ptrace_unlink(current
);
288 /* Reparent to init */
289 remove_parent(current
);
290 current
->parent
= child_reaper
;
291 current
->real_parent
= child_reaper
;
294 /* Set the exit signal to SIGCHLD so we signal init on exit */
295 current
->exit_signal
= SIGCHLD
;
297 if ((current
->policy
== SCHED_NORMAL
||
298 current
->policy
== SCHED_BATCH
)
299 && (task_nice(current
) < 0))
300 set_user_nice(current
, 0);
304 security_task_reparent_to_init(current
);
305 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
306 sizeof(current
->signal
->rlim
));
307 atomic_inc(&(INIT_USER
->__count
));
308 write_unlock_irq(&tasklist_lock
);
309 switch_uid(INIT_USER
);
312 void __set_special_pids(pid_t session
, pid_t pgrp
)
314 struct task_struct
*curr
= current
->group_leader
;
316 if (curr
->signal
->session
!= session
) {
317 detach_pid(curr
, PIDTYPE_SID
);
318 curr
->signal
->session
= session
;
319 attach_pid(curr
, PIDTYPE_SID
, session
);
321 if (process_group(curr
) != pgrp
) {
322 detach_pid(curr
, PIDTYPE_PGID
);
323 curr
->signal
->pgrp
= pgrp
;
324 attach_pid(curr
, PIDTYPE_PGID
, pgrp
);
328 void set_special_pids(pid_t session
, pid_t pgrp
)
330 write_lock_irq(&tasklist_lock
);
331 __set_special_pids(session
, pgrp
);
332 write_unlock_irq(&tasklist_lock
);
336 * Let kernel threads use this to say that they
337 * allow a certain signal (since daemonize() will
338 * have disabled all of them by default).
340 int allow_signal(int sig
)
342 if (!valid_signal(sig
) || sig
< 1)
345 spin_lock_irq(¤t
->sighand
->siglock
);
346 sigdelset(¤t
->blocked
, sig
);
348 /* Kernel threads handle their own signals.
349 Let the signal code know it'll be handled, so
350 that they don't get converted to SIGKILL or
351 just silently dropped */
352 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
355 spin_unlock_irq(¤t
->sighand
->siglock
);
359 EXPORT_SYMBOL(allow_signal
);
361 int disallow_signal(int sig
)
363 if (!valid_signal(sig
) || sig
< 1)
366 spin_lock_irq(¤t
->sighand
->siglock
);
367 sigaddset(¤t
->blocked
, sig
);
369 spin_unlock_irq(¤t
->sighand
->siglock
);
373 EXPORT_SYMBOL(disallow_signal
);
376 * Put all the gunge required to become a kernel thread without
377 * attached user resources in one place where it belongs.
380 void daemonize(const char *name
, ...)
383 struct fs_struct
*fs
;
386 va_start(args
, name
);
387 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
391 * If we were started as result of loading a module, close all of the
392 * user space pages. We don't need them, and if we didn't close them
393 * they would be locked into memory.
397 set_special_pids(1, 1);
398 mutex_lock(&tty_mutex
);
399 current
->signal
->tty
= NULL
;
400 mutex_unlock(&tty_mutex
);
402 /* Block and flush all signals */
403 sigfillset(&blocked
);
404 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
405 flush_signals(current
);
407 /* Become as one with the init task */
409 exit_fs(current
); /* current->fs->count--; */
412 atomic_inc(&fs
->count
);
413 exit_namespace(current
);
414 current
->namespace = init_task
.namespace;
415 get_namespace(current
->namespace);
417 current
->files
= init_task
.files
;
418 atomic_inc(¤t
->files
->count
);
423 EXPORT_SYMBOL(daemonize
);
425 static void close_files(struct files_struct
* files
)
433 * It is safe to dereference the fd table without RCU or
434 * ->file_lock because this is the last reference to the
437 fdt
= files_fdtable(files
);
441 if (i
>= fdt
->max_fdset
|| i
>= fdt
->max_fds
)
443 set
= fdt
->open_fds
->fds_bits
[j
++];
446 struct file
* file
= xchg(&fdt
->fd
[i
], NULL
);
448 filp_close(file
, files
);
456 struct files_struct
*get_files_struct(struct task_struct
*task
)
458 struct files_struct
*files
;
463 atomic_inc(&files
->count
);
469 void fastcall
put_files_struct(struct files_struct
*files
)
473 if (atomic_dec_and_test(&files
->count
)) {
476 * Free the fd and fdset arrays if we expanded them.
477 * If the fdtable was embedded, pass files for freeing
478 * at the end of the RCU grace period. Otherwise,
479 * you can free files immediately.
481 fdt
= files_fdtable(files
);
482 if (fdt
== &files
->fdtab
)
483 fdt
->free_files
= files
;
485 kmem_cache_free(files_cachep
, files
);
490 EXPORT_SYMBOL(put_files_struct
);
492 static inline void __exit_files(struct task_struct
*tsk
)
494 struct files_struct
* files
= tsk
->files
;
500 put_files_struct(files
);
504 void exit_files(struct task_struct
*tsk
)
509 static inline void __put_fs_struct(struct fs_struct
*fs
)
511 /* No need to hold fs->lock if we are killing it */
512 if (atomic_dec_and_test(&fs
->count
)) {
519 mntput(fs
->altrootmnt
);
521 kmem_cache_free(fs_cachep
, fs
);
525 void put_fs_struct(struct fs_struct
*fs
)
530 static inline void __exit_fs(struct task_struct
*tsk
)
532 struct fs_struct
* fs
= tsk
->fs
;
542 void exit_fs(struct task_struct
*tsk
)
547 EXPORT_SYMBOL_GPL(exit_fs
);
550 * Turn us into a lazy TLB process if we
553 static void exit_mm(struct task_struct
* tsk
)
555 struct mm_struct
*mm
= tsk
->mm
;
561 * Serialize with any possible pending coredump.
562 * We must hold mmap_sem around checking core_waiters
563 * and clearing tsk->mm. The core-inducing thread
564 * will increment core_waiters for each thread in the
565 * group with ->mm != NULL.
567 down_read(&mm
->mmap_sem
);
568 if (mm
->core_waiters
) {
569 up_read(&mm
->mmap_sem
);
570 down_write(&mm
->mmap_sem
);
571 if (!--mm
->core_waiters
)
572 complete(mm
->core_startup_done
);
573 up_write(&mm
->mmap_sem
);
575 wait_for_completion(&mm
->core_done
);
576 down_read(&mm
->mmap_sem
);
578 atomic_inc(&mm
->mm_count
);
579 if (mm
!= tsk
->active_mm
) BUG();
580 /* more a memory barrier than a real lock */
583 up_read(&mm
->mmap_sem
);
584 enter_lazy_tlb(mm
, current
);
589 static inline void choose_new_parent(task_t
*p
, task_t
*reaper
)
592 * Make sure we're not reparenting to ourselves and that
593 * the parent is not a zombie.
595 BUG_ON(p
== reaper
|| reaper
->exit_state
);
596 p
->real_parent
= reaper
;
599 static void reparent_thread(task_t
*p
, task_t
*father
, int traced
)
601 /* We don't want people slaying init. */
602 if (p
->exit_signal
!= -1)
603 p
->exit_signal
= SIGCHLD
;
605 if (p
->pdeath_signal
)
606 /* We already hold the tasklist_lock here. */
607 group_send_sig_info(p
->pdeath_signal
, SEND_SIG_NOINFO
, p
);
609 /* Move the child from its dying parent to the new one. */
610 if (unlikely(traced
)) {
611 /* Preserve ptrace links if someone else is tracing this child. */
612 list_del_init(&p
->ptrace_list
);
613 if (p
->parent
!= p
->real_parent
)
614 list_add(&p
->ptrace_list
, &p
->real_parent
->ptrace_children
);
616 /* If this child is being traced, then we're the one tracing it
617 * anyway, so let go of it.
621 p
->parent
= p
->real_parent
;
624 /* If we'd notified the old parent about this child's death,
625 * also notify the new parent.
627 if (p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
!= -1 &&
628 thread_group_empty(p
))
629 do_notify_parent(p
, p
->exit_signal
);
630 else if (p
->state
== TASK_TRACED
) {
632 * If it was at a trace stop, turn it into
633 * a normal stop since it's no longer being
641 * process group orphan check
642 * Case ii: Our child is in a different pgrp
643 * than we are, and it was the only connection
644 * outside, so the child pgrp is now orphaned.
646 if ((process_group(p
) != process_group(father
)) &&
647 (p
->signal
->session
== father
->signal
->session
)) {
648 int pgrp
= process_group(p
);
650 if (will_become_orphaned_pgrp(pgrp
, NULL
) && has_stopped_jobs(pgrp
)) {
651 __kill_pg_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
652 __kill_pg_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
658 * When we die, we re-parent all our children.
659 * Try to give them to another thread in our thread
660 * group, and if no such member exists, give it to
661 * the global child reaper process (ie "init")
663 static void forget_original_parent(struct task_struct
* father
,
664 struct list_head
*to_release
)
666 struct task_struct
*p
, *reaper
= father
;
667 struct list_head
*_p
, *_n
;
670 reaper
= next_thread(reaper
);
671 if (reaper
== father
) {
672 reaper
= child_reaper
;
675 } while (reaper
->exit_state
);
678 * There are only two places where our children can be:
680 * - in our child list
681 * - in our ptraced child list
683 * Search them and reparent children.
685 list_for_each_safe(_p
, _n
, &father
->children
) {
687 p
= list_entry(_p
,struct task_struct
,sibling
);
691 /* if father isn't the real parent, then ptrace must be enabled */
692 BUG_ON(father
!= p
->real_parent
&& !ptrace
);
694 if (father
== p
->real_parent
) {
695 /* reparent with a reaper, real father it's us */
696 choose_new_parent(p
, reaper
);
697 reparent_thread(p
, father
, 0);
699 /* reparent ptraced task to its real parent */
701 if (p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
!= -1 &&
702 thread_group_empty(p
))
703 do_notify_parent(p
, p
->exit_signal
);
707 * if the ptraced child is a zombie with exit_signal == -1
708 * we must collect it before we exit, or it will remain
709 * zombie forever since we prevented it from self-reap itself
710 * while it was being traced by us, to be able to see it in wait4.
712 if (unlikely(ptrace
&& p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
== -1))
713 list_add(&p
->ptrace_list
, to_release
);
715 list_for_each_safe(_p
, _n
, &father
->ptrace_children
) {
716 p
= list_entry(_p
,struct task_struct
,ptrace_list
);
717 choose_new_parent(p
, reaper
);
718 reparent_thread(p
, father
, 1);
723 * Send signals to all our closest relatives so that they know
724 * to properly mourn us..
726 static void exit_notify(struct task_struct
*tsk
)
729 struct task_struct
*t
;
730 struct list_head ptrace_dead
, *_p
, *_n
;
732 if (signal_pending(tsk
) && !(tsk
->signal
->flags
& SIGNAL_GROUP_EXIT
)
733 && !thread_group_empty(tsk
)) {
735 * This occurs when there was a race between our exit
736 * syscall and a group signal choosing us as the one to
737 * wake up. It could be that we are the only thread
738 * alerted to check for pending signals, but another thread
739 * should be woken now to take the signal since we will not.
740 * Now we'll wake all the threads in the group just to make
741 * sure someone gets all the pending signals.
743 read_lock(&tasklist_lock
);
744 spin_lock_irq(&tsk
->sighand
->siglock
);
745 for (t
= next_thread(tsk
); t
!= tsk
; t
= next_thread(t
))
746 if (!signal_pending(t
) && !(t
->flags
& PF_EXITING
)) {
747 recalc_sigpending_tsk(t
);
748 if (signal_pending(t
))
749 signal_wake_up(t
, 0);
751 spin_unlock_irq(&tsk
->sighand
->siglock
);
752 read_unlock(&tasklist_lock
);
755 write_lock_irq(&tasklist_lock
);
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)
766 INIT_LIST_HEAD(&ptrace_dead
);
767 forget_original_parent(tsk
, &ptrace_dead
);
768 BUG_ON(!list_empty(&tsk
->children
));
769 BUG_ON(!list_empty(&tsk
->ptrace_children
));
772 * Check to see if any process groups have become orphaned
773 * as a result of our exiting, and if they have any stopped
774 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
776 * Case i: Our father is in a different pgrp than we are
777 * and we were the only connection outside, so our pgrp
778 * is about to become orphaned.
781 t
= tsk
->real_parent
;
783 if ((process_group(t
) != process_group(tsk
)) &&
784 (t
->signal
->session
== tsk
->signal
->session
) &&
785 will_become_orphaned_pgrp(process_group(tsk
), tsk
) &&
786 has_stopped_jobs(process_group(tsk
))) {
787 __kill_pg_info(SIGHUP
, SEND_SIG_PRIV
, process_group(tsk
));
788 __kill_pg_info(SIGCONT
, SEND_SIG_PRIV
, process_group(tsk
));
791 /* Let father know we died
793 * Thread signals are configurable, but you aren't going to use
794 * that to send signals to arbitary processes.
795 * That stops right now.
797 * If the parent exec id doesn't match the exec id we saved
798 * when we started then we know the parent has changed security
801 * If our self_exec id doesn't match our parent_exec_id then
802 * we have changed execution domain as these two values started
803 * the same after a fork.
807 if (tsk
->exit_signal
!= SIGCHLD
&& tsk
->exit_signal
!= -1 &&
808 ( tsk
->parent_exec_id
!= t
->self_exec_id
||
809 tsk
->self_exec_id
!= tsk
->parent_exec_id
)
810 && !capable(CAP_KILL
))
811 tsk
->exit_signal
= SIGCHLD
;
814 /* If something other than our normal parent is ptracing us, then
815 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
816 * only has special meaning to our real parent.
818 if (tsk
->exit_signal
!= -1 && thread_group_empty(tsk
)) {
819 int signal
= tsk
->parent
== tsk
->real_parent
? tsk
->exit_signal
: SIGCHLD
;
820 do_notify_parent(tsk
, signal
);
821 } else if (tsk
->ptrace
) {
822 do_notify_parent(tsk
, SIGCHLD
);
826 if (tsk
->exit_signal
== -1 &&
827 (likely(tsk
->ptrace
== 0) ||
828 unlikely(tsk
->parent
->signal
->flags
& SIGNAL_GROUP_EXIT
)))
830 tsk
->exit_state
= state
;
832 write_unlock_irq(&tasklist_lock
);
834 list_for_each_safe(_p
, _n
, &ptrace_dead
) {
836 t
= list_entry(_p
,struct task_struct
,ptrace_list
);
840 /* If the process is dead, release it - nobody will wait for it */
841 if (state
== EXIT_DEAD
)
845 fastcall NORET_TYPE
void do_exit(long code
)
847 struct task_struct
*tsk
= current
;
850 profile_task_exit(tsk
);
852 WARN_ON(atomic_read(&tsk
->fs_excl
));
854 if (unlikely(in_interrupt()))
855 panic("Aiee, killing interrupt handler!");
856 if (unlikely(!tsk
->pid
))
857 panic("Attempted to kill the idle task!");
858 if (unlikely(tsk
== child_reaper
))
859 panic("Attempted to kill init!");
861 if (unlikely(current
->ptrace
& PT_TRACE_EXIT
)) {
862 current
->ptrace_message
= code
;
863 ptrace_notify((PTRACE_EVENT_EXIT
<< 8) | SIGTRAP
);
867 * We're taking recursive faults here in do_exit. Safest is to just
868 * leave this task alone and wait for reboot.
870 if (unlikely(tsk
->flags
& PF_EXITING
)) {
872 "Fixing recursive fault but reboot is needed!\n");
875 set_current_state(TASK_UNINTERRUPTIBLE
);
879 tsk
->flags
|= PF_EXITING
;
882 * Make sure we don't try to process any timer firings
883 * while we are already exiting.
885 tsk
->it_virt_expires
= cputime_zero
;
886 tsk
->it_prof_expires
= cputime_zero
;
887 tsk
->it_sched_expires
= 0;
889 if (unlikely(in_atomic()))
890 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
891 current
->comm
, current
->pid
,
894 acct_update_integrals(tsk
);
896 update_hiwater_rss(tsk
->mm
);
897 update_hiwater_vm(tsk
->mm
);
899 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
901 hrtimer_cancel(&tsk
->signal
->real_timer
);
902 exit_itimers(tsk
->signal
);
905 if (unlikely(tsk
->robust_list
))
906 exit_robust_list(tsk
);
908 if (unlikely(tsk
->compat_robust_list
))
909 compat_exit_robust_list(tsk
);
921 if (group_dead
&& tsk
->signal
->leader
)
922 disassociate_ctty(1);
924 module_put(task_thread_info(tsk
)->exec_domain
->module
);
926 module_put(tsk
->binfmt
->module
);
928 tsk
->exit_code
= code
;
929 proc_exit_connector(tsk
);
932 mpol_free(tsk
->mempolicy
);
933 tsk
->mempolicy
= NULL
;
936 * If DEBUG_MUTEXES is on, make sure we are holding no locks:
938 mutex_debug_check_no_locks_held(tsk
);
943 /* PF_DEAD causes final put_task_struct after we schedule. */
945 BUG_ON(tsk
->flags
& PF_DEAD
);
946 tsk
->flags
|= PF_DEAD
;
950 /* Avoid "noreturn function does return". */
954 EXPORT_SYMBOL_GPL(do_exit
);
956 NORET_TYPE
void complete_and_exit(struct completion
*comp
, long code
)
964 EXPORT_SYMBOL(complete_and_exit
);
966 asmlinkage
long sys_exit(int error_code
)
968 do_exit((error_code
&0xff)<<8);
971 task_t fastcall
*next_thread(const task_t
*p
)
973 return pid_task(p
->pids
[PIDTYPE_TGID
].pid_list
.next
, PIDTYPE_TGID
);
976 EXPORT_SYMBOL(next_thread
);
979 * Take down every thread in the group. This is called by fatal signals
980 * as well as by sys_exit_group (below).
983 do_group_exit(int exit_code
)
985 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
987 if (current
->signal
->flags
& SIGNAL_GROUP_EXIT
)
988 exit_code
= current
->signal
->group_exit_code
;
989 else if (!thread_group_empty(current
)) {
990 struct signal_struct
*const sig
= current
->signal
;
991 struct sighand_struct
*const sighand
= current
->sighand
;
992 read_lock(&tasklist_lock
);
993 spin_lock_irq(&sighand
->siglock
);
994 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
995 /* Another thread got here before we took the lock. */
996 exit_code
= sig
->group_exit_code
;
998 sig
->group_exit_code
= exit_code
;
999 zap_other_threads(current
);
1001 spin_unlock_irq(&sighand
->siglock
);
1002 read_unlock(&tasklist_lock
);
1010 * this kills every thread in the thread group. Note that any externally
1011 * wait4()-ing process will get the correct exit code - even if this
1012 * thread is not the thread group leader.
1014 asmlinkage
void sys_exit_group(int error_code
)
1016 do_group_exit((error_code
& 0xff) << 8);
1019 static int eligible_child(pid_t pid
, int options
, task_t
*p
)
1025 if (process_group(p
) != process_group(current
))
1027 } else if (pid
!= -1) {
1028 if (process_group(p
) != -pid
)
1033 * Do not consider detached threads that are
1036 if (p
->exit_signal
== -1 && !p
->ptrace
)
1039 /* Wait for all children (clone and not) if __WALL is set;
1040 * otherwise, wait for clone children *only* if __WCLONE is
1041 * set; otherwise, wait for non-clone children *only*. (Note:
1042 * A "clone" child here is one that reports to its parent
1043 * using a signal other than SIGCHLD.) */
1044 if (((p
->exit_signal
!= SIGCHLD
) ^ ((options
& __WCLONE
) != 0))
1045 && !(options
& __WALL
))
1048 * Do not consider thread group leaders that are
1049 * in a non-empty thread group:
1051 if (current
->tgid
!= p
->tgid
&& delay_group_leader(p
))
1054 if (security_task_wait(p
))
1060 static int wait_noreap_copyout(task_t
*p
, pid_t pid
, uid_t uid
,
1061 int why
, int status
,
1062 struct siginfo __user
*infop
,
1063 struct rusage __user
*rusagep
)
1065 int retval
= rusagep
? getrusage(p
, RUSAGE_BOTH
, rusagep
) : 0;
1068 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1070 retval
= put_user(0, &infop
->si_errno
);
1072 retval
= put_user((short)why
, &infop
->si_code
);
1074 retval
= put_user(pid
, &infop
->si_pid
);
1076 retval
= put_user(uid
, &infop
->si_uid
);
1078 retval
= put_user(status
, &infop
->si_status
);
1085 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1086 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1087 * the lock and this task is uninteresting. If we return nonzero, we have
1088 * released the lock and the system call should return.
1090 static int wait_task_zombie(task_t
*p
, int noreap
,
1091 struct siginfo __user
*infop
,
1092 int __user
*stat_addr
, struct rusage __user
*ru
)
1094 unsigned long state
;
1098 if (unlikely(noreap
)) {
1101 int exit_code
= p
->exit_code
;
1104 if (unlikely(p
->exit_state
!= EXIT_ZOMBIE
))
1106 if (unlikely(p
->exit_signal
== -1 && p
->ptrace
== 0))
1109 read_unlock(&tasklist_lock
);
1110 if ((exit_code
& 0x7f) == 0) {
1112 status
= exit_code
>> 8;
1114 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1115 status
= exit_code
& 0x7f;
1117 return wait_noreap_copyout(p
, pid
, uid
, why
,
1122 * Try to move the task's state to DEAD
1123 * only one thread is allowed to do this:
1125 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1126 if (state
!= EXIT_ZOMBIE
) {
1127 BUG_ON(state
!= EXIT_DEAD
);
1130 if (unlikely(p
->exit_signal
== -1 && p
->ptrace
== 0)) {
1132 * This can only happen in a race with a ptraced thread
1133 * dying on another processor.
1138 if (likely(p
->real_parent
== p
->parent
) && likely(p
->signal
)) {
1139 struct signal_struct
*psig
;
1140 struct signal_struct
*sig
;
1143 * The resource counters for the group leader are in its
1144 * own task_struct. Those for dead threads in the group
1145 * are in its signal_struct, as are those for the child
1146 * processes it has previously reaped. All these
1147 * accumulate in the parent's signal_struct c* fields.
1149 * We don't bother to take a lock here to protect these
1150 * p->signal fields, because they are only touched by
1151 * __exit_signal, which runs with tasklist_lock
1152 * write-locked anyway, and so is excluded here. We do
1153 * need to protect the access to p->parent->signal fields,
1154 * as other threads in the parent group can be right
1155 * here reaping other children at the same time.
1157 spin_lock_irq(&p
->parent
->sighand
->siglock
);
1158 psig
= p
->parent
->signal
;
1161 cputime_add(psig
->cutime
,
1162 cputime_add(p
->utime
,
1163 cputime_add(sig
->utime
,
1166 cputime_add(psig
->cstime
,
1167 cputime_add(p
->stime
,
1168 cputime_add(sig
->stime
,
1171 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1173 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1175 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1177 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1178 spin_unlock_irq(&p
->parent
->sighand
->siglock
);
1182 * Now we are sure this task is interesting, and no other
1183 * thread can reap it because we set its state to EXIT_DEAD.
1185 read_unlock(&tasklist_lock
);
1187 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1188 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1189 ? p
->signal
->group_exit_code
: p
->exit_code
;
1190 if (!retval
&& stat_addr
)
1191 retval
= put_user(status
, stat_addr
);
1192 if (!retval
&& infop
)
1193 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1194 if (!retval
&& infop
)
1195 retval
= put_user(0, &infop
->si_errno
);
1196 if (!retval
&& infop
) {
1199 if ((status
& 0x7f) == 0) {
1203 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1206 retval
= put_user((short)why
, &infop
->si_code
);
1208 retval
= put_user(status
, &infop
->si_status
);
1210 if (!retval
&& infop
)
1211 retval
= put_user(p
->pid
, &infop
->si_pid
);
1212 if (!retval
&& infop
)
1213 retval
= put_user(p
->uid
, &infop
->si_uid
);
1215 // TODO: is this safe?
1216 p
->exit_state
= EXIT_ZOMBIE
;
1220 if (p
->real_parent
!= p
->parent
) {
1221 write_lock_irq(&tasklist_lock
);
1222 /* Double-check with lock held. */
1223 if (p
->real_parent
!= p
->parent
) {
1225 // TODO: is this safe?
1226 p
->exit_state
= EXIT_ZOMBIE
;
1228 * If this is not a detached task, notify the parent.
1229 * If it's still not detached after that, don't release
1232 if (p
->exit_signal
!= -1) {
1233 do_notify_parent(p
, p
->exit_signal
);
1234 if (p
->exit_signal
!= -1)
1238 write_unlock_irq(&tasklist_lock
);
1247 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1248 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1249 * the lock and this task is uninteresting. If we return nonzero, we have
1250 * released the lock and the system call should return.
1252 static int wait_task_stopped(task_t
*p
, int delayed_group_leader
, int noreap
,
1253 struct siginfo __user
*infop
,
1254 int __user
*stat_addr
, struct rusage __user
*ru
)
1256 int retval
, exit_code
;
1260 if (delayed_group_leader
&& !(p
->ptrace
& PT_PTRACED
) &&
1261 p
->signal
&& p
->signal
->group_stop_count
> 0)
1263 * A group stop is in progress and this is the group leader.
1264 * We won't report until all threads have stopped.
1269 * Now we are pretty sure this task is interesting.
1270 * Make sure it doesn't get reaped out from under us while we
1271 * give up the lock and then examine it below. We don't want to
1272 * keep holding onto the tasklist_lock while we call getrusage and
1273 * possibly take page faults for user memory.
1276 read_unlock(&tasklist_lock
);
1278 if (unlikely(noreap
)) {
1281 int why
= (p
->ptrace
& PT_PTRACED
) ? CLD_TRAPPED
: CLD_STOPPED
;
1283 exit_code
= p
->exit_code
;
1284 if (unlikely(!exit_code
) ||
1285 unlikely(p
->state
& TASK_TRACED
))
1287 return wait_noreap_copyout(p
, pid
, uid
,
1288 why
, (exit_code
<< 8) | 0x7f,
1292 write_lock_irq(&tasklist_lock
);
1295 * This uses xchg to be atomic with the thread resuming and setting
1296 * it. It must also be done with the write lock held to prevent a
1297 * race with the EXIT_ZOMBIE case.
1299 exit_code
= xchg(&p
->exit_code
, 0);
1300 if (unlikely(p
->exit_state
)) {
1302 * The task resumed and then died. Let the next iteration
1303 * catch it in EXIT_ZOMBIE. Note that exit_code might
1304 * already be zero here if it resumed and did _exit(0).
1305 * The task itself is dead and won't touch exit_code again;
1306 * other processors in this function are locked out.
1308 p
->exit_code
= exit_code
;
1311 if (unlikely(exit_code
== 0)) {
1313 * Another thread in this function got to it first, or it
1314 * resumed, or it resumed and then died.
1316 write_unlock_irq(&tasklist_lock
);
1320 * We are returning to the wait loop without having successfully
1321 * removed the process and having released the lock. We cannot
1322 * continue, since the "p" task pointer is potentially stale.
1324 * Return -EAGAIN, and do_wait() will restart the loop from the
1325 * beginning. Do _not_ re-acquire the lock.
1330 /* move to end of parent's list to avoid starvation */
1334 write_unlock_irq(&tasklist_lock
);
1336 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1337 if (!retval
&& stat_addr
)
1338 retval
= put_user((exit_code
<< 8) | 0x7f, stat_addr
);
1339 if (!retval
&& infop
)
1340 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1341 if (!retval
&& infop
)
1342 retval
= put_user(0, &infop
->si_errno
);
1343 if (!retval
&& infop
)
1344 retval
= put_user((short)((p
->ptrace
& PT_PTRACED
)
1345 ? CLD_TRAPPED
: CLD_STOPPED
),
1347 if (!retval
&& infop
)
1348 retval
= put_user(exit_code
, &infop
->si_status
);
1349 if (!retval
&& infop
)
1350 retval
= put_user(p
->pid
, &infop
->si_pid
);
1351 if (!retval
&& infop
)
1352 retval
= put_user(p
->uid
, &infop
->si_uid
);
1362 * Handle do_wait work for one task in a live, non-stopped state.
1363 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1364 * the lock and this task is uninteresting. If we return nonzero, we have
1365 * released the lock and the system call should return.
1367 static int wait_task_continued(task_t
*p
, int noreap
,
1368 struct siginfo __user
*infop
,
1369 int __user
*stat_addr
, struct rusage __user
*ru
)
1375 if (unlikely(!p
->signal
))
1378 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1381 spin_lock_irq(&p
->sighand
->siglock
);
1382 /* Re-check with the lock held. */
1383 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1384 spin_unlock_irq(&p
->sighand
->siglock
);
1388 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1389 spin_unlock_irq(&p
->sighand
->siglock
);
1394 read_unlock(&tasklist_lock
);
1397 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1399 if (!retval
&& stat_addr
)
1400 retval
= put_user(0xffff, stat_addr
);
1404 retval
= wait_noreap_copyout(p
, pid
, uid
,
1405 CLD_CONTINUED
, SIGCONT
,
1407 BUG_ON(retval
== 0);
1414 static inline int my_ptrace_child(struct task_struct
*p
)
1416 if (!(p
->ptrace
& PT_PTRACED
))
1418 if (!(p
->ptrace
& PT_ATTACHED
))
1421 * This child was PTRACE_ATTACH'd. We should be seeing it only if
1422 * we are the attacher. If we are the real parent, this is a race
1423 * inside ptrace_attach. It is waiting for the tasklist_lock,
1424 * which we have to switch the parent links, but has already set
1425 * the flags in p->ptrace.
1427 return (p
->parent
!= p
->real_parent
);
1430 static long do_wait(pid_t pid
, int options
, struct siginfo __user
*infop
,
1431 int __user
*stat_addr
, struct rusage __user
*ru
)
1433 DECLARE_WAITQUEUE(wait
, current
);
1434 struct task_struct
*tsk
;
1437 add_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1440 * We will set this flag if we see any child that might later
1441 * match our criteria, even if we are not able to reap it yet.
1444 current
->state
= TASK_INTERRUPTIBLE
;
1445 read_lock(&tasklist_lock
);
1448 struct task_struct
*p
;
1449 struct list_head
*_p
;
1452 list_for_each(_p
,&tsk
->children
) {
1453 p
= list_entry(_p
,struct task_struct
,sibling
);
1455 ret
= eligible_child(pid
, options
, p
);
1462 * When we hit the race with PTRACE_ATTACH,
1463 * we will not report this child. But the
1464 * race means it has not yet been moved to
1465 * our ptrace_children list, so we need to
1466 * set the flag here to avoid a spurious ECHILD
1467 * when the race happens with the only child.
1470 if (!my_ptrace_child(p
))
1475 * It's stopped now, so it might later
1476 * continue, exit, or stop again.
1479 if (!(options
& WUNTRACED
) &&
1480 !my_ptrace_child(p
))
1482 retval
= wait_task_stopped(p
, ret
== 2,
1483 (options
& WNOWAIT
),
1486 if (retval
== -EAGAIN
)
1488 if (retval
!= 0) /* He released the lock. */
1493 if (p
->exit_state
== EXIT_DEAD
)
1495 // case EXIT_ZOMBIE:
1496 if (p
->exit_state
== EXIT_ZOMBIE
) {
1498 * Eligible but we cannot release
1502 goto check_continued
;
1503 if (!likely(options
& WEXITED
))
1505 retval
= wait_task_zombie(
1506 p
, (options
& WNOWAIT
),
1507 infop
, stat_addr
, ru
);
1508 /* He released the lock. */
1515 * It's running now, so it might later
1516 * exit, stop, or stop and then continue.
1519 if (!unlikely(options
& WCONTINUED
))
1521 retval
= wait_task_continued(
1522 p
, (options
& WNOWAIT
),
1523 infop
, stat_addr
, ru
);
1524 if (retval
!= 0) /* He released the lock. */
1530 list_for_each(_p
, &tsk
->ptrace_children
) {
1531 p
= list_entry(_p
, struct task_struct
,
1533 if (!eligible_child(pid
, options
, p
))
1539 if (options
& __WNOTHREAD
)
1541 tsk
= next_thread(tsk
);
1542 if (tsk
->signal
!= current
->signal
)
1544 } while (tsk
!= current
);
1546 read_unlock(&tasklist_lock
);
1549 if (options
& WNOHANG
)
1551 retval
= -ERESTARTSYS
;
1552 if (signal_pending(current
))
1559 current
->state
= TASK_RUNNING
;
1560 remove_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1566 * For a WNOHANG return, clear out all the fields
1567 * we would set so the user can easily tell the
1571 retval
= put_user(0, &infop
->si_signo
);
1573 retval
= put_user(0, &infop
->si_errno
);
1575 retval
= put_user(0, &infop
->si_code
);
1577 retval
= put_user(0, &infop
->si_pid
);
1579 retval
= put_user(0, &infop
->si_uid
);
1581 retval
= put_user(0, &infop
->si_status
);
1587 asmlinkage
long sys_waitid(int which
, pid_t pid
,
1588 struct siginfo __user
*infop
, int options
,
1589 struct rusage __user
*ru
)
1593 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1595 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1615 ret
= do_wait(pid
, options
, infop
, NULL
, ru
);
1617 /* avoid REGPARM breakage on x86: */
1618 prevent_tail_call(ret
);
1622 asmlinkage
long sys_wait4(pid_t pid
, int __user
*stat_addr
,
1623 int options
, struct rusage __user
*ru
)
1627 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1628 __WNOTHREAD
|__WCLONE
|__WALL
))
1630 ret
= do_wait(pid
, options
| WEXITED
, NULL
, stat_addr
, ru
);
1632 /* avoid REGPARM breakage on x86: */
1633 prevent_tail_call(ret
);
1637 #ifdef __ARCH_WANT_SYS_WAITPID
1640 * sys_waitpid() remains for compatibility. waitpid() should be
1641 * implemented by calling sys_wait4() from libc.a.
1643 asmlinkage
long sys_waitpid(pid_t pid
, int __user
*stat_addr
, int options
)
1645 return sys_wait4(pid
, stat_addr
, options
, NULL
);