]>
git.proxmox.com Git - mirror_ubuntu-eoan-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/smp_lock.h>
11 #include <linux/module.h>
12 #include <linux/capability.h>
13 #include <linux/completion.h>
14 #include <linux/personality.h>
15 #include <linux/tty.h>
16 #include <linux/namespace.h>
17 #include <linux/key.h>
18 #include <linux/security.h>
19 #include <linux/cpu.h>
20 #include <linux/acct.h>
21 #include <linux/file.h>
22 #include <linux/binfmts.h>
23 #include <linux/ptrace.h>
24 #include <linux/profile.h>
25 #include <linux/mount.h>
26 #include <linux/proc_fs.h>
27 #include <linux/mempolicy.h>
28 #include <linux/taskstats_kern.h>
29 #include <linux/delayacct.h>
30 #include <linux/cpuset.h>
31 #include <linux/syscalls.h>
32 #include <linux/signal.h>
33 #include <linux/posix-timers.h>
34 #include <linux/cn_proc.h>
35 #include <linux/mutex.h>
36 #include <linux/futex.h>
37 #include <linux/compat.h>
38 #include <linux/pipe_fs_i.h>
39 #include <linux/audit.h> /* for audit_free() */
40 #include <linux/resource.h>
42 #include <asm/uaccess.h>
43 #include <asm/unistd.h>
44 #include <asm/pgtable.h>
45 #include <asm/mmu_context.h>
47 extern void sem_exit (void);
48 extern struct task_struct
*child_reaper
;
50 static void exit_mm(struct task_struct
* tsk
);
52 static void __unhash_process(struct task_struct
*p
)
55 detach_pid(p
, PIDTYPE_PID
);
56 if (thread_group_leader(p
)) {
57 detach_pid(p
, PIDTYPE_PGID
);
58 detach_pid(p
, PIDTYPE_SID
);
60 list_del_rcu(&p
->tasks
);
61 __get_cpu_var(process_counts
)--;
63 list_del_rcu(&p
->thread_group
);
68 * This function expects the tasklist_lock write-locked.
70 static void __exit_signal(struct task_struct
*tsk
)
72 struct signal_struct
*sig
= tsk
->signal
;
73 struct sighand_struct
*sighand
;
76 BUG_ON(!atomic_read(&sig
->count
));
79 sighand
= rcu_dereference(tsk
->sighand
);
80 spin_lock(&sighand
->siglock
);
82 posix_cpu_timers_exit(tsk
);
83 if (atomic_dec_and_test(&sig
->count
))
84 posix_cpu_timers_exit_group(tsk
);
87 * If there is any task waiting for the group exit
90 if (sig
->group_exit_task
&& atomic_read(&sig
->count
) == sig
->notify_count
) {
91 wake_up_process(sig
->group_exit_task
);
92 sig
->group_exit_task
= NULL
;
94 if (tsk
== sig
->curr_target
)
95 sig
->curr_target
= next_thread(tsk
);
97 * Accumulate here the counters for all threads but the
98 * group leader as they die, so they can be added into
99 * the process-wide totals when those are taken.
100 * The group leader stays around as a zombie as long
101 * as there are other threads. When it gets reaped,
102 * the exit.c code will add its counts into these totals.
103 * We won't ever get here for the group leader, since it
104 * will have been the last reference on the signal_struct.
106 sig
->utime
= cputime_add(sig
->utime
, tsk
->utime
);
107 sig
->stime
= cputime_add(sig
->stime
, tsk
->stime
);
108 sig
->min_flt
+= tsk
->min_flt
;
109 sig
->maj_flt
+= tsk
->maj_flt
;
110 sig
->nvcsw
+= tsk
->nvcsw
;
111 sig
->nivcsw
+= tsk
->nivcsw
;
112 sig
->sched_time
+= tsk
->sched_time
;
113 sig
= NULL
; /* Marker for below. */
116 __unhash_process(tsk
);
120 spin_unlock(&sighand
->siglock
);
123 __cleanup_sighand(sighand
);
124 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
125 flush_sigqueue(&tsk
->pending
);
127 flush_sigqueue(&sig
->shared_pending
);
128 __cleanup_signal(sig
);
132 static void delayed_put_task_struct(struct rcu_head
*rhp
)
134 put_task_struct(container_of(rhp
, struct task_struct
, rcu
));
137 void release_task(struct task_struct
* p
)
139 struct task_struct
*leader
;
142 atomic_dec(&p
->user
->processes
);
143 write_lock_irq(&tasklist_lock
);
145 BUG_ON(!list_empty(&p
->ptrace_list
) || !list_empty(&p
->ptrace_children
));
149 * If we are the last non-leader member of the thread
150 * group, and the leader is zombie, then notify the
151 * group leader's parent process. (if it wants notification.)
154 leader
= p
->group_leader
;
155 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
156 BUG_ON(leader
->exit_signal
== -1);
157 do_notify_parent(leader
, leader
->exit_signal
);
159 * If we were the last child thread and the leader has
160 * exited already, and the leader's parent ignores SIGCHLD,
161 * then we are the one who should release the leader.
163 * do_notify_parent() will have marked it self-reaping in
166 zap_leader
= (leader
->exit_signal
== -1);
170 write_unlock_irq(&tasklist_lock
);
173 call_rcu(&p
->rcu
, delayed_put_task_struct
);
176 if (unlikely(zap_leader
))
181 * This checks not only the pgrp, but falls back on the pid if no
182 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
185 int session_of_pgrp(int pgrp
)
187 struct task_struct
*p
;
190 read_lock(&tasklist_lock
);
191 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
192 if (p
->signal
->session
> 0) {
193 sid
= p
->signal
->session
;
196 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
197 p
= find_task_by_pid(pgrp
);
199 sid
= p
->signal
->session
;
201 read_unlock(&tasklist_lock
);
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(int pgrp
, struct task_struct
*ignored_task
)
216 struct task_struct
*p
;
219 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
220 if (p
== ignored_task
222 || p
->real_parent
->pid
== 1)
224 if (process_group(p
->real_parent
) != pgrp
225 && p
->real_parent
->signal
->session
== p
->signal
->session
) {
229 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
230 return ret
; /* (sighing) "Often!" */
233 int is_orphaned_pgrp(int pgrp
)
237 read_lock(&tasklist_lock
);
238 retval
= will_become_orphaned_pgrp(pgrp
, NULL
);
239 read_unlock(&tasklist_lock
);
244 static int has_stopped_jobs(int pgrp
)
247 struct task_struct
*p
;
249 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
250 if (p
->state
!= TASK_STOPPED
)
253 /* If p is stopped by a debugger on a signal that won't
254 stop it, then don't count p as stopped. This isn't
255 perfect but it's a good approximation. */
256 if (unlikely (p
->ptrace
)
257 && p
->exit_code
!= SIGSTOP
258 && p
->exit_code
!= SIGTSTP
259 && p
->exit_code
!= SIGTTOU
260 && p
->exit_code
!= SIGTTIN
)
265 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
270 * reparent_to_init - Reparent the calling kernel thread to the init task.
272 * If a kernel thread is launched as a result of a system call, or if
273 * it ever exits, it should generally reparent itself to init so that
274 * it is correctly cleaned up on exit.
276 * The various task state such as scheduling policy and priority may have
277 * been inherited from a user process, so we reset them to sane values here.
279 * NOTE that reparent_to_init() gives the caller full capabilities.
281 static void reparent_to_init(void)
283 write_lock_irq(&tasklist_lock
);
285 ptrace_unlink(current
);
286 /* Reparent to init */
287 remove_parent(current
);
288 current
->parent
= child_reaper
;
289 current
->real_parent
= child_reaper
;
292 /* Set the exit signal to SIGCHLD so we signal init on exit */
293 current
->exit_signal
= SIGCHLD
;
295 if ((current
->policy
== SCHED_NORMAL
||
296 current
->policy
== SCHED_BATCH
)
297 && (task_nice(current
) < 0))
298 set_user_nice(current
, 0);
302 security_task_reparent_to_init(current
);
303 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
304 sizeof(current
->signal
->rlim
));
305 atomic_inc(&(INIT_USER
->__count
));
306 write_unlock_irq(&tasklist_lock
);
307 switch_uid(INIT_USER
);
310 void __set_special_pids(pid_t session
, pid_t pgrp
)
312 struct task_struct
*curr
= current
->group_leader
;
314 if (curr
->signal
->session
!= session
) {
315 detach_pid(curr
, PIDTYPE_SID
);
316 curr
->signal
->session
= session
;
317 attach_pid(curr
, PIDTYPE_SID
, session
);
319 if (process_group(curr
) != pgrp
) {
320 detach_pid(curr
, PIDTYPE_PGID
);
321 curr
->signal
->pgrp
= pgrp
;
322 attach_pid(curr
, PIDTYPE_PGID
, pgrp
);
326 void set_special_pids(pid_t session
, pid_t pgrp
)
328 write_lock_irq(&tasklist_lock
);
329 __set_special_pids(session
, pgrp
);
330 write_unlock_irq(&tasklist_lock
);
334 * Let kernel threads use this to say that they
335 * allow a certain signal (since daemonize() will
336 * have disabled all of them by default).
338 int allow_signal(int sig
)
340 if (!valid_signal(sig
) || sig
< 1)
343 spin_lock_irq(¤t
->sighand
->siglock
);
344 sigdelset(¤t
->blocked
, sig
);
346 /* Kernel threads handle their own signals.
347 Let the signal code know it'll be handled, so
348 that they don't get converted to SIGKILL or
349 just silently dropped */
350 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
353 spin_unlock_irq(¤t
->sighand
->siglock
);
357 EXPORT_SYMBOL(allow_signal
);
359 int disallow_signal(int sig
)
361 if (!valid_signal(sig
) || sig
< 1)
364 spin_lock_irq(¤t
->sighand
->siglock
);
365 sigaddset(¤t
->blocked
, sig
);
367 spin_unlock_irq(¤t
->sighand
->siglock
);
371 EXPORT_SYMBOL(disallow_signal
);
374 * Put all the gunge required to become a kernel thread without
375 * attached user resources in one place where it belongs.
378 void daemonize(const char *name
, ...)
381 struct fs_struct
*fs
;
384 va_start(args
, name
);
385 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
389 * If we were started as result of loading a module, close all of the
390 * user space pages. We don't need them, and if we didn't close them
391 * they would be locked into memory.
395 set_special_pids(1, 1);
396 mutex_lock(&tty_mutex
);
397 current
->signal
->tty
= NULL
;
398 mutex_unlock(&tty_mutex
);
400 /* Block and flush all signals */
401 sigfillset(&blocked
);
402 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
403 flush_signals(current
);
405 /* Become as one with the init task */
407 exit_fs(current
); /* current->fs->count--; */
410 atomic_inc(&fs
->count
);
411 exit_namespace(current
);
412 current
->namespace = init_task
.namespace;
413 get_namespace(current
->namespace);
415 current
->files
= init_task
.files
;
416 atomic_inc(¤t
->files
->count
);
421 EXPORT_SYMBOL(daemonize
);
423 static void close_files(struct files_struct
* files
)
431 * It is safe to dereference the fd table without RCU or
432 * ->file_lock because this is the last reference to the
435 fdt
= files_fdtable(files
);
439 if (i
>= fdt
->max_fdset
|| i
>= fdt
->max_fds
)
441 set
= fdt
->open_fds
->fds_bits
[j
++];
444 struct file
* file
= xchg(&fdt
->fd
[i
], NULL
);
446 filp_close(file
, files
);
454 struct files_struct
*get_files_struct(struct task_struct
*task
)
456 struct files_struct
*files
;
461 atomic_inc(&files
->count
);
467 void fastcall
put_files_struct(struct files_struct
*files
)
471 if (atomic_dec_and_test(&files
->count
)) {
474 * Free the fd and fdset arrays if we expanded them.
475 * If the fdtable was embedded, pass files for freeing
476 * at the end of the RCU grace period. Otherwise,
477 * you can free files immediately.
479 fdt
= files_fdtable(files
);
480 if (fdt
== &files
->fdtab
)
481 fdt
->free_files
= files
;
483 kmem_cache_free(files_cachep
, files
);
488 EXPORT_SYMBOL(put_files_struct
);
490 static inline void __exit_files(struct task_struct
*tsk
)
492 struct files_struct
* files
= tsk
->files
;
498 put_files_struct(files
);
502 void exit_files(struct task_struct
*tsk
)
507 static inline void __put_fs_struct(struct fs_struct
*fs
)
509 /* No need to hold fs->lock if we are killing it */
510 if (atomic_dec_and_test(&fs
->count
)) {
517 mntput(fs
->altrootmnt
);
519 kmem_cache_free(fs_cachep
, fs
);
523 void put_fs_struct(struct fs_struct
*fs
)
528 static inline void __exit_fs(struct task_struct
*tsk
)
530 struct fs_struct
* fs
= tsk
->fs
;
540 void exit_fs(struct task_struct
*tsk
)
545 EXPORT_SYMBOL_GPL(exit_fs
);
548 * Turn us into a lazy TLB process if we
551 static void exit_mm(struct task_struct
* tsk
)
553 struct mm_struct
*mm
= tsk
->mm
;
559 * Serialize with any possible pending coredump.
560 * We must hold mmap_sem around checking core_waiters
561 * and clearing tsk->mm. The core-inducing thread
562 * will increment core_waiters for each thread in the
563 * group with ->mm != NULL.
565 down_read(&mm
->mmap_sem
);
566 if (mm
->core_waiters
) {
567 up_read(&mm
->mmap_sem
);
568 down_write(&mm
->mmap_sem
);
569 if (!--mm
->core_waiters
)
570 complete(mm
->core_startup_done
);
571 up_write(&mm
->mmap_sem
);
573 wait_for_completion(&mm
->core_done
);
574 down_read(&mm
->mmap_sem
);
576 atomic_inc(&mm
->mm_count
);
577 BUG_ON(mm
!= tsk
->active_mm
);
578 /* more a memory barrier than a real lock */
581 up_read(&mm
->mmap_sem
);
582 enter_lazy_tlb(mm
, current
);
588 choose_new_parent(struct task_struct
*p
, struct task_struct
*reaper
)
591 * Make sure we're not reparenting to ourselves and that
592 * the parent is not a zombie.
594 BUG_ON(p
== reaper
|| reaper
->exit_state
);
595 p
->real_parent
= reaper
;
599 reparent_thread(struct task_struct
*p
, struct task_struct
*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")
664 forget_original_parent(struct task_struct
*father
, 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
;
848 struct taskstats
*tidstats
;
852 profile_task_exit(tsk
);
854 WARN_ON(atomic_read(&tsk
->fs_excl
));
856 if (unlikely(in_interrupt()))
857 panic("Aiee, killing interrupt handler!");
858 if (unlikely(!tsk
->pid
))
859 panic("Attempted to kill the idle task!");
860 if (unlikely(tsk
== child_reaper
))
861 panic("Attempted to kill init!");
863 if (unlikely(current
->ptrace
& PT_TRACE_EXIT
)) {
864 current
->ptrace_message
= code
;
865 ptrace_notify((PTRACE_EVENT_EXIT
<< 8) | SIGTRAP
);
869 * We're taking recursive faults here in do_exit. Safest is to just
870 * leave this task alone and wait for reboot.
872 if (unlikely(tsk
->flags
& PF_EXITING
)) {
874 "Fixing recursive fault but reboot is needed!\n");
877 set_current_state(TASK_UNINTERRUPTIBLE
);
881 tsk
->flags
|= PF_EXITING
;
883 if (unlikely(in_atomic()))
884 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
885 current
->comm
, current
->pid
,
888 taskstats_exit_alloc(&tidstats
, &mycpu
);
890 acct_update_integrals(tsk
);
892 update_hiwater_rss(tsk
->mm
);
893 update_hiwater_vm(tsk
->mm
);
895 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
897 hrtimer_cancel(&tsk
->signal
->real_timer
);
898 exit_itimers(tsk
->signal
);
900 acct_collect(code
, group_dead
);
901 if (unlikely(tsk
->robust_list
))
902 exit_robust_list(tsk
);
903 #if defined(CONFIG_FUTEX) && defined(CONFIG_COMPAT)
904 if (unlikely(tsk
->compat_robust_list
))
905 compat_exit_robust_list(tsk
);
907 if (unlikely(tsk
->audit_context
))
909 taskstats_exit_send(tsk
, tidstats
, group_dead
, mycpu
);
910 taskstats_exit_free(tidstats
);
924 if (group_dead
&& tsk
->signal
->leader
)
925 disassociate_ctty(1);
927 module_put(task_thread_info(tsk
)->exec_domain
->module
);
929 module_put(tsk
->binfmt
->module
);
931 tsk
->exit_code
= code
;
932 proc_exit_connector(tsk
);
935 mpol_free(tsk
->mempolicy
);
936 tsk
->mempolicy
= NULL
;
939 * This must happen late, after the PID is not
942 if (unlikely(!list_empty(&tsk
->pi_state_list
)))
943 exit_pi_state_list(tsk
);
944 if (unlikely(current
->pi_state_cache
))
945 kfree(current
->pi_state_cache
);
947 * Make sure we are holding no locks:
949 debug_check_no_locks_held(tsk
);
954 if (tsk
->splice_pipe
)
955 __free_pipe_info(tsk
->splice_pipe
);
957 /* PF_DEAD causes final put_task_struct after we schedule. */
959 BUG_ON(tsk
->flags
& PF_DEAD
);
960 tsk
->flags
|= PF_DEAD
;
964 /* Avoid "noreturn function does return". */
968 EXPORT_SYMBOL_GPL(do_exit
);
970 NORET_TYPE
void complete_and_exit(struct completion
*comp
, long code
)
978 EXPORT_SYMBOL(complete_and_exit
);
980 asmlinkage
long sys_exit(int error_code
)
982 do_exit((error_code
&0xff)<<8);
986 * Take down every thread in the group. This is called by fatal signals
987 * as well as by sys_exit_group (below).
990 do_group_exit(int exit_code
)
992 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
994 if (current
->signal
->flags
& SIGNAL_GROUP_EXIT
)
995 exit_code
= current
->signal
->group_exit_code
;
996 else if (!thread_group_empty(current
)) {
997 struct signal_struct
*const sig
= current
->signal
;
998 struct sighand_struct
*const sighand
= current
->sighand
;
999 spin_lock_irq(&sighand
->siglock
);
1000 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
1001 /* Another thread got here before we took the lock. */
1002 exit_code
= sig
->group_exit_code
;
1004 sig
->group_exit_code
= exit_code
;
1005 zap_other_threads(current
);
1007 spin_unlock_irq(&sighand
->siglock
);
1015 * this kills every thread in the thread group. Note that any externally
1016 * wait4()-ing process will get the correct exit code - even if this
1017 * thread is not the thread group leader.
1019 asmlinkage
void sys_exit_group(int error_code
)
1021 do_group_exit((error_code
& 0xff) << 8);
1024 static int eligible_child(pid_t pid
, int options
, struct task_struct
*p
)
1030 if (process_group(p
) != process_group(current
))
1032 } else if (pid
!= -1) {
1033 if (process_group(p
) != -pid
)
1038 * Do not consider detached threads that are
1041 if (p
->exit_signal
== -1 && !p
->ptrace
)
1044 /* Wait for all children (clone and not) if __WALL is set;
1045 * otherwise, wait for clone children *only* if __WCLONE is
1046 * set; otherwise, wait for non-clone children *only*. (Note:
1047 * A "clone" child here is one that reports to its parent
1048 * using a signal other than SIGCHLD.) */
1049 if (((p
->exit_signal
!= SIGCHLD
) ^ ((options
& __WCLONE
) != 0))
1050 && !(options
& __WALL
))
1053 * Do not consider thread group leaders that are
1054 * in a non-empty thread group:
1056 if (delay_group_leader(p
))
1059 if (security_task_wait(p
))
1065 static int wait_noreap_copyout(struct task_struct
*p
, pid_t pid
, uid_t uid
,
1066 int why
, int status
,
1067 struct siginfo __user
*infop
,
1068 struct rusage __user
*rusagep
)
1070 int retval
= rusagep
? getrusage(p
, RUSAGE_BOTH
, rusagep
) : 0;
1074 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1076 retval
= put_user(0, &infop
->si_errno
);
1078 retval
= put_user((short)why
, &infop
->si_code
);
1080 retval
= put_user(pid
, &infop
->si_pid
);
1082 retval
= put_user(uid
, &infop
->si_uid
);
1084 retval
= put_user(status
, &infop
->si_status
);
1091 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1092 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1093 * the lock and this task is uninteresting. If we return nonzero, we have
1094 * released the lock and the system call should return.
1096 static int wait_task_zombie(struct task_struct
*p
, int noreap
,
1097 struct siginfo __user
*infop
,
1098 int __user
*stat_addr
, struct rusage __user
*ru
)
1100 unsigned long state
;
1104 if (unlikely(noreap
)) {
1107 int exit_code
= p
->exit_code
;
1110 if (unlikely(p
->exit_state
!= EXIT_ZOMBIE
))
1112 if (unlikely(p
->exit_signal
== -1 && p
->ptrace
== 0))
1115 read_unlock(&tasklist_lock
);
1116 if ((exit_code
& 0x7f) == 0) {
1118 status
= exit_code
>> 8;
1120 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1121 status
= exit_code
& 0x7f;
1123 return wait_noreap_copyout(p
, pid
, uid
, why
,
1128 * Try to move the task's state to DEAD
1129 * only one thread is allowed to do this:
1131 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1132 if (state
!= EXIT_ZOMBIE
) {
1133 BUG_ON(state
!= EXIT_DEAD
);
1136 if (unlikely(p
->exit_signal
== -1 && p
->ptrace
== 0)) {
1138 * This can only happen in a race with a ptraced thread
1139 * dying on another processor.
1144 if (likely(p
->real_parent
== p
->parent
) && likely(p
->signal
)) {
1145 struct signal_struct
*psig
;
1146 struct signal_struct
*sig
;
1149 * The resource counters for the group leader are in its
1150 * own task_struct. Those for dead threads in the group
1151 * are in its signal_struct, as are those for the child
1152 * processes it has previously reaped. All these
1153 * accumulate in the parent's signal_struct c* fields.
1155 * We don't bother to take a lock here to protect these
1156 * p->signal fields, because they are only touched by
1157 * __exit_signal, which runs with tasklist_lock
1158 * write-locked anyway, and so is excluded here. We do
1159 * need to protect the access to p->parent->signal fields,
1160 * as other threads in the parent group can be right
1161 * here reaping other children at the same time.
1163 spin_lock_irq(&p
->parent
->sighand
->siglock
);
1164 psig
= p
->parent
->signal
;
1167 cputime_add(psig
->cutime
,
1168 cputime_add(p
->utime
,
1169 cputime_add(sig
->utime
,
1172 cputime_add(psig
->cstime
,
1173 cputime_add(p
->stime
,
1174 cputime_add(sig
->stime
,
1177 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1179 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1181 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1183 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1184 spin_unlock_irq(&p
->parent
->sighand
->siglock
);
1188 * Now we are sure this task is interesting, and no other
1189 * thread can reap it because we set its state to EXIT_DEAD.
1191 read_unlock(&tasklist_lock
);
1193 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1194 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1195 ? p
->signal
->group_exit_code
: p
->exit_code
;
1196 if (!retval
&& stat_addr
)
1197 retval
= put_user(status
, stat_addr
);
1198 if (!retval
&& infop
)
1199 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1200 if (!retval
&& infop
)
1201 retval
= put_user(0, &infop
->si_errno
);
1202 if (!retval
&& infop
) {
1205 if ((status
& 0x7f) == 0) {
1209 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1212 retval
= put_user((short)why
, &infop
->si_code
);
1214 retval
= put_user(status
, &infop
->si_status
);
1216 if (!retval
&& infop
)
1217 retval
= put_user(p
->pid
, &infop
->si_pid
);
1218 if (!retval
&& infop
)
1219 retval
= put_user(p
->uid
, &infop
->si_uid
);
1221 // TODO: is this safe?
1222 p
->exit_state
= EXIT_ZOMBIE
;
1226 if (p
->real_parent
!= p
->parent
) {
1227 write_lock_irq(&tasklist_lock
);
1228 /* Double-check with lock held. */
1229 if (p
->real_parent
!= p
->parent
) {
1231 // TODO: is this safe?
1232 p
->exit_state
= EXIT_ZOMBIE
;
1234 * If this is not a detached task, notify the parent.
1235 * If it's still not detached after that, don't release
1238 if (p
->exit_signal
!= -1) {
1239 do_notify_parent(p
, p
->exit_signal
);
1240 if (p
->exit_signal
!= -1)
1244 write_unlock_irq(&tasklist_lock
);
1253 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1254 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1255 * the lock and this task is uninteresting. If we return nonzero, we have
1256 * released the lock and the system call should return.
1258 static int wait_task_stopped(struct task_struct
*p
, int delayed_group_leader
,
1259 int noreap
, struct siginfo __user
*infop
,
1260 int __user
*stat_addr
, struct rusage __user
*ru
)
1262 int retval
, exit_code
;
1266 if (delayed_group_leader
&& !(p
->ptrace
& PT_PTRACED
) &&
1267 p
->signal
&& p
->signal
->group_stop_count
> 0)
1269 * A group stop is in progress and this is the group leader.
1270 * We won't report until all threads have stopped.
1275 * Now we are pretty sure this task is interesting.
1276 * Make sure it doesn't get reaped out from under us while we
1277 * give up the lock and then examine it below. We don't want to
1278 * keep holding onto the tasklist_lock while we call getrusage and
1279 * possibly take page faults for user memory.
1282 read_unlock(&tasklist_lock
);
1284 if (unlikely(noreap
)) {
1287 int why
= (p
->ptrace
& PT_PTRACED
) ? CLD_TRAPPED
: CLD_STOPPED
;
1289 exit_code
= p
->exit_code
;
1290 if (unlikely(!exit_code
) ||
1291 unlikely(p
->state
& TASK_TRACED
))
1293 return wait_noreap_copyout(p
, pid
, uid
,
1294 why
, (exit_code
<< 8) | 0x7f,
1298 write_lock_irq(&tasklist_lock
);
1301 * This uses xchg to be atomic with the thread resuming and setting
1302 * it. It must also be done with the write lock held to prevent a
1303 * race with the EXIT_ZOMBIE case.
1305 exit_code
= xchg(&p
->exit_code
, 0);
1306 if (unlikely(p
->exit_state
)) {
1308 * The task resumed and then died. Let the next iteration
1309 * catch it in EXIT_ZOMBIE. Note that exit_code might
1310 * already be zero here if it resumed and did _exit(0).
1311 * The task itself is dead and won't touch exit_code again;
1312 * other processors in this function are locked out.
1314 p
->exit_code
= exit_code
;
1317 if (unlikely(exit_code
== 0)) {
1319 * Another thread in this function got to it first, or it
1320 * resumed, or it resumed and then died.
1322 write_unlock_irq(&tasklist_lock
);
1326 * We are returning to the wait loop without having successfully
1327 * removed the process and having released the lock. We cannot
1328 * continue, since the "p" task pointer is potentially stale.
1330 * Return -EAGAIN, and do_wait() will restart the loop from the
1331 * beginning. Do _not_ re-acquire the lock.
1336 /* move to end of parent's list to avoid starvation */
1340 write_unlock_irq(&tasklist_lock
);
1342 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1343 if (!retval
&& stat_addr
)
1344 retval
= put_user((exit_code
<< 8) | 0x7f, stat_addr
);
1345 if (!retval
&& infop
)
1346 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1347 if (!retval
&& infop
)
1348 retval
= put_user(0, &infop
->si_errno
);
1349 if (!retval
&& infop
)
1350 retval
= put_user((short)((p
->ptrace
& PT_PTRACED
)
1351 ? CLD_TRAPPED
: CLD_STOPPED
),
1353 if (!retval
&& infop
)
1354 retval
= put_user(exit_code
, &infop
->si_status
);
1355 if (!retval
&& infop
)
1356 retval
= put_user(p
->pid
, &infop
->si_pid
);
1357 if (!retval
&& infop
)
1358 retval
= put_user(p
->uid
, &infop
->si_uid
);
1368 * Handle do_wait work for one task in a live, non-stopped state.
1369 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1370 * the lock and this task is uninteresting. If we return nonzero, we have
1371 * released the lock and the system call should return.
1373 static int wait_task_continued(struct task_struct
*p
, int noreap
,
1374 struct siginfo __user
*infop
,
1375 int __user
*stat_addr
, struct rusage __user
*ru
)
1381 if (unlikely(!p
->signal
))
1384 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1387 spin_lock_irq(&p
->sighand
->siglock
);
1388 /* Re-check with the lock held. */
1389 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1390 spin_unlock_irq(&p
->sighand
->siglock
);
1394 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1395 spin_unlock_irq(&p
->sighand
->siglock
);
1400 read_unlock(&tasklist_lock
);
1403 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1405 if (!retval
&& stat_addr
)
1406 retval
= put_user(0xffff, stat_addr
);
1410 retval
= wait_noreap_copyout(p
, pid
, uid
,
1411 CLD_CONTINUED
, SIGCONT
,
1413 BUG_ON(retval
== 0);
1420 static inline int my_ptrace_child(struct task_struct
*p
)
1422 if (!(p
->ptrace
& PT_PTRACED
))
1424 if (!(p
->ptrace
& PT_ATTACHED
))
1427 * This child was PTRACE_ATTACH'd. We should be seeing it only if
1428 * we are the attacher. If we are the real parent, this is a race
1429 * inside ptrace_attach. It is waiting for the tasklist_lock,
1430 * which we have to switch the parent links, but has already set
1431 * the flags in p->ptrace.
1433 return (p
->parent
!= p
->real_parent
);
1436 static long do_wait(pid_t pid
, int options
, struct siginfo __user
*infop
,
1437 int __user
*stat_addr
, struct rusage __user
*ru
)
1439 DECLARE_WAITQUEUE(wait
, current
);
1440 struct task_struct
*tsk
;
1443 add_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1446 * We will set this flag if we see any child that might later
1447 * match our criteria, even if we are not able to reap it yet.
1450 current
->state
= TASK_INTERRUPTIBLE
;
1451 read_lock(&tasklist_lock
);
1454 struct task_struct
*p
;
1455 struct list_head
*_p
;
1458 list_for_each(_p
,&tsk
->children
) {
1459 p
= list_entry(_p
, struct task_struct
, sibling
);
1461 ret
= eligible_child(pid
, options
, p
);
1468 * When we hit the race with PTRACE_ATTACH,
1469 * we will not report this child. But the
1470 * race means it has not yet been moved to
1471 * our ptrace_children list, so we need to
1472 * set the flag here to avoid a spurious ECHILD
1473 * when the race happens with the only child.
1476 if (!my_ptrace_child(p
))
1481 * It's stopped now, so it might later
1482 * continue, exit, or stop again.
1485 if (!(options
& WUNTRACED
) &&
1486 !my_ptrace_child(p
))
1488 retval
= wait_task_stopped(p
, ret
== 2,
1489 (options
& WNOWAIT
),
1492 if (retval
== -EAGAIN
)
1494 if (retval
!= 0) /* He released the lock. */
1499 if (p
->exit_state
== EXIT_DEAD
)
1501 // case EXIT_ZOMBIE:
1502 if (p
->exit_state
== EXIT_ZOMBIE
) {
1504 * Eligible but we cannot release
1508 goto check_continued
;
1509 if (!likely(options
& WEXITED
))
1511 retval
= wait_task_zombie(
1512 p
, (options
& WNOWAIT
),
1513 infop
, stat_addr
, ru
);
1514 /* He released the lock. */
1521 * It's running now, so it might later
1522 * exit, stop, or stop and then continue.
1525 if (!unlikely(options
& WCONTINUED
))
1527 retval
= wait_task_continued(
1528 p
, (options
& WNOWAIT
),
1529 infop
, stat_addr
, ru
);
1530 if (retval
!= 0) /* He released the lock. */
1536 list_for_each(_p
, &tsk
->ptrace_children
) {
1537 p
= list_entry(_p
, struct task_struct
,
1539 if (!eligible_child(pid
, options
, p
))
1545 if (options
& __WNOTHREAD
)
1547 tsk
= next_thread(tsk
);
1548 BUG_ON(tsk
->signal
!= current
->signal
);
1549 } while (tsk
!= current
);
1551 read_unlock(&tasklist_lock
);
1554 if (options
& WNOHANG
)
1556 retval
= -ERESTARTSYS
;
1557 if (signal_pending(current
))
1564 current
->state
= TASK_RUNNING
;
1565 remove_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1571 * For a WNOHANG return, clear out all the fields
1572 * we would set so the user can easily tell the
1576 retval
= put_user(0, &infop
->si_signo
);
1578 retval
= put_user(0, &infop
->si_errno
);
1580 retval
= put_user(0, &infop
->si_code
);
1582 retval
= put_user(0, &infop
->si_pid
);
1584 retval
= put_user(0, &infop
->si_uid
);
1586 retval
= put_user(0, &infop
->si_status
);
1592 asmlinkage
long sys_waitid(int which
, pid_t pid
,
1593 struct siginfo __user
*infop
, int options
,
1594 struct rusage __user
*ru
)
1598 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1600 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1620 ret
= do_wait(pid
, options
, infop
, NULL
, ru
);
1622 /* avoid REGPARM breakage on x86: */
1623 prevent_tail_call(ret
);
1627 asmlinkage
long sys_wait4(pid_t pid
, int __user
*stat_addr
,
1628 int options
, struct rusage __user
*ru
)
1632 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1633 __WNOTHREAD
|__WCLONE
|__WALL
))
1635 ret
= do_wait(pid
, options
| WEXITED
, NULL
, stat_addr
, ru
);
1637 /* avoid REGPARM breakage on x86: */
1638 prevent_tail_call(ret
);
1642 #ifdef __ARCH_WANT_SYS_WAITPID
1645 * sys_waitpid() remains for compatibility. waitpid() should be
1646 * implemented by calling sys_wait4() from libc.a.
1648 asmlinkage
long sys_waitpid(pid_t pid
, int __user
*stat_addr
, int options
)
1650 return sys_wait4(pid
, stat_addr
, options
, NULL
);