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. */
115 __unhash_process(tsk
);
118 cleanup_sighand(tsk
);
119 spin_unlock(&sighand
->siglock
);
122 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
123 flush_sigqueue(&tsk
->pending
);
125 flush_sigqueue(&sig
->shared_pending
);
126 __cleanup_signal(sig
);
130 void release_task(struct task_struct
* p
)
134 struct dentry
*proc_dentry
;
137 atomic_dec(&p
->user
->processes
);
138 spin_lock(&p
->proc_lock
);
139 proc_dentry
= proc_pid_unhash(p
);
140 write_lock_irq(&tasklist_lock
);
142 BUG_ON(!list_empty(&p
->ptrace_list
) || !list_empty(&p
->ptrace_children
));
146 * If we are the last non-leader member of the thread
147 * group, and the leader is zombie, then notify the
148 * group leader's parent process. (if it wants notification.)
151 leader
= p
->group_leader
;
152 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
153 BUG_ON(leader
->exit_signal
== -1);
154 do_notify_parent(leader
, leader
->exit_signal
);
156 * If we were the last child thread and the leader has
157 * exited already, and the leader's parent ignores SIGCHLD,
158 * then we are the one who should release the leader.
160 * do_notify_parent() will have marked it self-reaping in
163 zap_leader
= (leader
->exit_signal
== -1);
167 write_unlock_irq(&tasklist_lock
);
168 spin_unlock(&p
->proc_lock
);
169 proc_pid_flush(proc_dentry
);
174 if (unlikely(zap_leader
))
179 * This checks not only the pgrp, but falls back on the pid if no
180 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
183 int session_of_pgrp(int pgrp
)
185 struct task_struct
*p
;
188 read_lock(&tasklist_lock
);
189 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
190 if (p
->signal
->session
> 0) {
191 sid
= p
->signal
->session
;
194 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
195 p
= find_task_by_pid(pgrp
);
197 sid
= p
->signal
->session
;
199 read_unlock(&tasklist_lock
);
205 * Determine if a process group is "orphaned", according to the POSIX
206 * definition in 2.2.2.52. Orphaned process groups are not to be affected
207 * by terminal-generated stop signals. Newly orphaned process groups are
208 * to receive a SIGHUP and a SIGCONT.
210 * "I ask you, have you ever known what it is to be an orphan?"
212 static int will_become_orphaned_pgrp(int pgrp
, task_t
*ignored_task
)
214 struct task_struct
*p
;
217 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
218 if (p
== ignored_task
220 || p
->real_parent
->pid
== 1)
222 if (process_group(p
->real_parent
) != pgrp
223 && p
->real_parent
->signal
->session
== p
->signal
->session
) {
227 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
228 return ret
; /* (sighing) "Often!" */
231 int is_orphaned_pgrp(int pgrp
)
235 read_lock(&tasklist_lock
);
236 retval
= will_become_orphaned_pgrp(pgrp
, NULL
);
237 read_unlock(&tasklist_lock
);
242 static int has_stopped_jobs(int pgrp
)
245 struct task_struct
*p
;
247 do_each_task_pid(pgrp
, PIDTYPE_PGID
, p
) {
248 if (p
->state
!= TASK_STOPPED
)
251 /* If p is stopped by a debugger on a signal that won't
252 stop it, then don't count p as stopped. This isn't
253 perfect but it's a good approximation. */
254 if (unlikely (p
->ptrace
)
255 && p
->exit_code
!= SIGSTOP
256 && p
->exit_code
!= SIGTSTP
257 && p
->exit_code
!= SIGTTOU
258 && p
->exit_code
!= SIGTTIN
)
263 } while_each_task_pid(pgrp
, PIDTYPE_PGID
, p
);
268 * reparent_to_init - Reparent the calling kernel thread to the init task.
270 * If a kernel thread is launched as a result of a system call, or if
271 * it ever exits, it should generally reparent itself to init so that
272 * it is correctly cleaned up on exit.
274 * The various task state such as scheduling policy and priority may have
275 * been inherited from a user process, so we reset them to sane values here.
277 * NOTE that reparent_to_init() gives the caller full capabilities.
279 static void reparent_to_init(void)
281 write_lock_irq(&tasklist_lock
);
283 ptrace_unlink(current
);
284 /* Reparent to init */
285 remove_parent(current
);
286 current
->parent
= child_reaper
;
287 current
->real_parent
= child_reaper
;
290 /* Set the exit signal to SIGCHLD so we signal init on exit */
291 current
->exit_signal
= SIGCHLD
;
293 if ((current
->policy
== SCHED_NORMAL
||
294 current
->policy
== SCHED_BATCH
)
295 && (task_nice(current
) < 0))
296 set_user_nice(current
, 0);
300 security_task_reparent_to_init(current
);
301 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
302 sizeof(current
->signal
->rlim
));
303 atomic_inc(&(INIT_USER
->__count
));
304 write_unlock_irq(&tasklist_lock
);
305 switch_uid(INIT_USER
);
308 void __set_special_pids(pid_t session
, pid_t pgrp
)
310 struct task_struct
*curr
= current
->group_leader
;
312 if (curr
->signal
->session
!= session
) {
313 detach_pid(curr
, PIDTYPE_SID
);
314 curr
->signal
->session
= session
;
315 attach_pid(curr
, PIDTYPE_SID
, session
);
317 if (process_group(curr
) != pgrp
) {
318 detach_pid(curr
, PIDTYPE_PGID
);
319 curr
->signal
->pgrp
= pgrp
;
320 attach_pid(curr
, PIDTYPE_PGID
, pgrp
);
324 void set_special_pids(pid_t session
, pid_t pgrp
)
326 write_lock_irq(&tasklist_lock
);
327 __set_special_pids(session
, pgrp
);
328 write_unlock_irq(&tasklist_lock
);
332 * Let kernel threads use this to say that they
333 * allow a certain signal (since daemonize() will
334 * have disabled all of them by default).
336 int allow_signal(int sig
)
338 if (!valid_signal(sig
) || sig
< 1)
341 spin_lock_irq(¤t
->sighand
->siglock
);
342 sigdelset(¤t
->blocked
, sig
);
344 /* Kernel threads handle their own signals.
345 Let the signal code know it'll be handled, so
346 that they don't get converted to SIGKILL or
347 just silently dropped */
348 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
351 spin_unlock_irq(¤t
->sighand
->siglock
);
355 EXPORT_SYMBOL(allow_signal
);
357 int disallow_signal(int sig
)
359 if (!valid_signal(sig
) || sig
< 1)
362 spin_lock_irq(¤t
->sighand
->siglock
);
363 sigaddset(¤t
->blocked
, sig
);
365 spin_unlock_irq(¤t
->sighand
->siglock
);
369 EXPORT_SYMBOL(disallow_signal
);
372 * Put all the gunge required to become a kernel thread without
373 * attached user resources in one place where it belongs.
376 void daemonize(const char *name
, ...)
379 struct fs_struct
*fs
;
382 va_start(args
, name
);
383 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
387 * If we were started as result of loading a module, close all of the
388 * user space pages. We don't need them, and if we didn't close them
389 * they would be locked into memory.
393 set_special_pids(1, 1);
394 mutex_lock(&tty_mutex
);
395 current
->signal
->tty
= NULL
;
396 mutex_unlock(&tty_mutex
);
398 /* Block and flush all signals */
399 sigfillset(&blocked
);
400 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
401 flush_signals(current
);
403 /* Become as one with the init task */
405 exit_fs(current
); /* current->fs->count--; */
408 atomic_inc(&fs
->count
);
409 exit_namespace(current
);
410 current
->namespace = init_task
.namespace;
411 get_namespace(current
->namespace);
413 current
->files
= init_task
.files
;
414 atomic_inc(¤t
->files
->count
);
419 EXPORT_SYMBOL(daemonize
);
421 static void close_files(struct files_struct
* files
)
429 * It is safe to dereference the fd table without RCU or
430 * ->file_lock because this is the last reference to the
433 fdt
= files_fdtable(files
);
437 if (i
>= fdt
->max_fdset
|| i
>= fdt
->max_fds
)
439 set
= fdt
->open_fds
->fds_bits
[j
++];
442 struct file
* file
= xchg(&fdt
->fd
[i
], NULL
);
444 filp_close(file
, files
);
452 struct files_struct
*get_files_struct(struct task_struct
*task
)
454 struct files_struct
*files
;
459 atomic_inc(&files
->count
);
465 void fastcall
put_files_struct(struct files_struct
*files
)
469 if (atomic_dec_and_test(&files
->count
)) {
472 * Free the fd and fdset arrays if we expanded them.
473 * If the fdtable was embedded, pass files for freeing
474 * at the end of the RCU grace period. Otherwise,
475 * you can free files immediately.
477 fdt
= files_fdtable(files
);
478 if (fdt
== &files
->fdtab
)
479 fdt
->free_files
= files
;
481 kmem_cache_free(files_cachep
, files
);
486 EXPORT_SYMBOL(put_files_struct
);
488 static inline void __exit_files(struct task_struct
*tsk
)
490 struct files_struct
* files
= tsk
->files
;
496 put_files_struct(files
);
500 void exit_files(struct task_struct
*tsk
)
505 static inline void __put_fs_struct(struct fs_struct
*fs
)
507 /* No need to hold fs->lock if we are killing it */
508 if (atomic_dec_and_test(&fs
->count
)) {
515 mntput(fs
->altrootmnt
);
517 kmem_cache_free(fs_cachep
, fs
);
521 void put_fs_struct(struct fs_struct
*fs
)
526 static inline void __exit_fs(struct task_struct
*tsk
)
528 struct fs_struct
* fs
= tsk
->fs
;
538 void exit_fs(struct task_struct
*tsk
)
543 EXPORT_SYMBOL_GPL(exit_fs
);
546 * Turn us into a lazy TLB process if we
549 static void exit_mm(struct task_struct
* tsk
)
551 struct mm_struct
*mm
= tsk
->mm
;
557 * Serialize with any possible pending coredump.
558 * We must hold mmap_sem around checking core_waiters
559 * and clearing tsk->mm. The core-inducing thread
560 * will increment core_waiters for each thread in the
561 * group with ->mm != NULL.
563 down_read(&mm
->mmap_sem
);
564 if (mm
->core_waiters
) {
565 up_read(&mm
->mmap_sem
);
566 down_write(&mm
->mmap_sem
);
567 if (!--mm
->core_waiters
)
568 complete(mm
->core_startup_done
);
569 up_write(&mm
->mmap_sem
);
571 wait_for_completion(&mm
->core_done
);
572 down_read(&mm
->mmap_sem
);
574 atomic_inc(&mm
->mm_count
);
575 if (mm
!= tsk
->active_mm
) BUG();
576 /* more a memory barrier than a real lock */
579 up_read(&mm
->mmap_sem
);
580 enter_lazy_tlb(mm
, current
);
585 static inline void choose_new_parent(task_t
*p
, task_t
*reaper
)
588 * Make sure we're not reparenting to ourselves and that
589 * the parent is not a zombie.
591 BUG_ON(p
== reaper
|| reaper
->exit_state
);
592 p
->real_parent
= reaper
;
595 static void reparent_thread(task_t
*p
, task_t
*father
, int traced
)
597 /* We don't want people slaying init. */
598 if (p
->exit_signal
!= -1)
599 p
->exit_signal
= SIGCHLD
;
601 if (p
->pdeath_signal
)
602 /* We already hold the tasklist_lock here. */
603 group_send_sig_info(p
->pdeath_signal
, SEND_SIG_NOINFO
, p
);
605 /* Move the child from its dying parent to the new one. */
606 if (unlikely(traced
)) {
607 /* Preserve ptrace links if someone else is tracing this child. */
608 list_del_init(&p
->ptrace_list
);
609 if (p
->parent
!= p
->real_parent
)
610 list_add(&p
->ptrace_list
, &p
->real_parent
->ptrace_children
);
612 /* If this child is being traced, then we're the one tracing it
613 * anyway, so let go of it.
617 p
->parent
= p
->real_parent
;
620 /* If we'd notified the old parent about this child's death,
621 * also notify the new parent.
623 if (p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
!= -1 &&
624 thread_group_empty(p
))
625 do_notify_parent(p
, p
->exit_signal
);
626 else if (p
->state
== TASK_TRACED
) {
628 * If it was at a trace stop, turn it into
629 * a normal stop since it's no longer being
637 * process group orphan check
638 * Case ii: Our child is in a different pgrp
639 * than we are, and it was the only connection
640 * outside, so the child pgrp is now orphaned.
642 if ((process_group(p
) != process_group(father
)) &&
643 (p
->signal
->session
== father
->signal
->session
)) {
644 int pgrp
= process_group(p
);
646 if (will_become_orphaned_pgrp(pgrp
, NULL
) && has_stopped_jobs(pgrp
)) {
647 __kill_pg_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
648 __kill_pg_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
654 * When we die, we re-parent all our children.
655 * Try to give them to another thread in our thread
656 * group, and if no such member exists, give it to
657 * the global child reaper process (ie "init")
659 static void forget_original_parent(struct task_struct
* father
,
660 struct list_head
*to_release
)
662 struct task_struct
*p
, *reaper
= father
;
663 struct list_head
*_p
, *_n
;
666 reaper
= next_thread(reaper
);
667 if (reaper
== father
) {
668 reaper
= child_reaper
;
671 } while (reaper
->exit_state
);
674 * There are only two places where our children can be:
676 * - in our child list
677 * - in our ptraced child list
679 * Search them and reparent children.
681 list_for_each_safe(_p
, _n
, &father
->children
) {
683 p
= list_entry(_p
,struct task_struct
,sibling
);
687 /* if father isn't the real parent, then ptrace must be enabled */
688 BUG_ON(father
!= p
->real_parent
&& !ptrace
);
690 if (father
== p
->real_parent
) {
691 /* reparent with a reaper, real father it's us */
692 choose_new_parent(p
, reaper
);
693 reparent_thread(p
, father
, 0);
695 /* reparent ptraced task to its real parent */
697 if (p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
!= -1 &&
698 thread_group_empty(p
))
699 do_notify_parent(p
, p
->exit_signal
);
703 * if the ptraced child is a zombie with exit_signal == -1
704 * we must collect it before we exit, or it will remain
705 * zombie forever since we prevented it from self-reap itself
706 * while it was being traced by us, to be able to see it in wait4.
708 if (unlikely(ptrace
&& p
->exit_state
== EXIT_ZOMBIE
&& p
->exit_signal
== -1))
709 list_add(&p
->ptrace_list
, to_release
);
711 list_for_each_safe(_p
, _n
, &father
->ptrace_children
) {
712 p
= list_entry(_p
,struct task_struct
,ptrace_list
);
713 choose_new_parent(p
, reaper
);
714 reparent_thread(p
, father
, 1);
719 * Send signals to all our closest relatives so that they know
720 * to properly mourn us..
722 static void exit_notify(struct task_struct
*tsk
)
725 struct task_struct
*t
;
726 struct list_head ptrace_dead
, *_p
, *_n
;
728 if (signal_pending(tsk
) && !(tsk
->signal
->flags
& SIGNAL_GROUP_EXIT
)
729 && !thread_group_empty(tsk
)) {
731 * This occurs when there was a race between our exit
732 * syscall and a group signal choosing us as the one to
733 * wake up. It could be that we are the only thread
734 * alerted to check for pending signals, but another thread
735 * should be woken now to take the signal since we will not.
736 * Now we'll wake all the threads in the group just to make
737 * sure someone gets all the pending signals.
739 read_lock(&tasklist_lock
);
740 spin_lock_irq(&tsk
->sighand
->siglock
);
741 for (t
= next_thread(tsk
); t
!= tsk
; t
= next_thread(t
))
742 if (!signal_pending(t
) && !(t
->flags
& PF_EXITING
)) {
743 recalc_sigpending_tsk(t
);
744 if (signal_pending(t
))
745 signal_wake_up(t
, 0);
747 spin_unlock_irq(&tsk
->sighand
->siglock
);
748 read_unlock(&tasklist_lock
);
751 write_lock_irq(&tasklist_lock
);
754 * This does two things:
756 * A. Make init inherit all the child processes
757 * B. Check to see if any process groups have become orphaned
758 * as a result of our exiting, and if they have any stopped
759 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
762 INIT_LIST_HEAD(&ptrace_dead
);
763 forget_original_parent(tsk
, &ptrace_dead
);
764 BUG_ON(!list_empty(&tsk
->children
));
765 BUG_ON(!list_empty(&tsk
->ptrace_children
));
768 * Check to see if any process groups have become orphaned
769 * as a result of our exiting, and if they have any stopped
770 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
772 * Case i: Our father is in a different pgrp than we are
773 * and we were the only connection outside, so our pgrp
774 * is about to become orphaned.
777 t
= tsk
->real_parent
;
779 if ((process_group(t
) != process_group(tsk
)) &&
780 (t
->signal
->session
== tsk
->signal
->session
) &&
781 will_become_orphaned_pgrp(process_group(tsk
), tsk
) &&
782 has_stopped_jobs(process_group(tsk
))) {
783 __kill_pg_info(SIGHUP
, SEND_SIG_PRIV
, process_group(tsk
));
784 __kill_pg_info(SIGCONT
, SEND_SIG_PRIV
, process_group(tsk
));
787 /* Let father know we died
789 * Thread signals are configurable, but you aren't going to use
790 * that to send signals to arbitary processes.
791 * That stops right now.
793 * If the parent exec id doesn't match the exec id we saved
794 * when we started then we know the parent has changed security
797 * If our self_exec id doesn't match our parent_exec_id then
798 * we have changed execution domain as these two values started
799 * the same after a fork.
803 if (tsk
->exit_signal
!= SIGCHLD
&& tsk
->exit_signal
!= -1 &&
804 ( tsk
->parent_exec_id
!= t
->self_exec_id
||
805 tsk
->self_exec_id
!= tsk
->parent_exec_id
)
806 && !capable(CAP_KILL
))
807 tsk
->exit_signal
= SIGCHLD
;
810 /* If something other than our normal parent is ptracing us, then
811 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
812 * only has special meaning to our real parent.
814 if (tsk
->exit_signal
!= -1 && thread_group_empty(tsk
)) {
815 int signal
= tsk
->parent
== tsk
->real_parent
? tsk
->exit_signal
: SIGCHLD
;
816 do_notify_parent(tsk
, signal
);
817 } else if (tsk
->ptrace
) {
818 do_notify_parent(tsk
, SIGCHLD
);
822 if (tsk
->exit_signal
== -1 &&
823 (likely(tsk
->ptrace
== 0) ||
824 unlikely(tsk
->parent
->signal
->flags
& SIGNAL_GROUP_EXIT
)))
826 tsk
->exit_state
= state
;
828 write_unlock_irq(&tasklist_lock
);
830 list_for_each_safe(_p
, _n
, &ptrace_dead
) {
832 t
= list_entry(_p
,struct task_struct
,ptrace_list
);
836 /* If the process is dead, release it - nobody will wait for it */
837 if (state
== EXIT_DEAD
)
841 fastcall NORET_TYPE
void do_exit(long code
)
843 struct task_struct
*tsk
= current
;
846 profile_task_exit(tsk
);
848 WARN_ON(atomic_read(&tsk
->fs_excl
));
850 if (unlikely(in_interrupt()))
851 panic("Aiee, killing interrupt handler!");
852 if (unlikely(!tsk
->pid
))
853 panic("Attempted to kill the idle task!");
854 if (unlikely(tsk
== child_reaper
))
855 panic("Attempted to kill init!");
857 if (unlikely(current
->ptrace
& PT_TRACE_EXIT
)) {
858 current
->ptrace_message
= code
;
859 ptrace_notify((PTRACE_EVENT_EXIT
<< 8) | SIGTRAP
);
863 * We're taking recursive faults here in do_exit. Safest is to just
864 * leave this task alone and wait for reboot.
866 if (unlikely(tsk
->flags
& PF_EXITING
)) {
868 "Fixing recursive fault but reboot is needed!\n");
871 set_current_state(TASK_UNINTERRUPTIBLE
);
875 tsk
->flags
|= PF_EXITING
;
878 * Make sure we don't try to process any timer firings
879 * while we are already exiting.
881 tsk
->it_virt_expires
= cputime_zero
;
882 tsk
->it_prof_expires
= cputime_zero
;
883 tsk
->it_sched_expires
= 0;
885 if (unlikely(in_atomic()))
886 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
887 current
->comm
, current
->pid
,
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
);
901 if (unlikely(tsk
->robust_list
))
902 exit_robust_list(tsk
);
904 if (unlikely(tsk
->compat_robust_list
))
905 compat_exit_robust_list(tsk
);
917 if (group_dead
&& tsk
->signal
->leader
)
918 disassociate_ctty(1);
920 module_put(task_thread_info(tsk
)->exec_domain
->module
);
922 module_put(tsk
->binfmt
->module
);
924 tsk
->exit_code
= code
;
925 proc_exit_connector(tsk
);
928 mpol_free(tsk
->mempolicy
);
929 tsk
->mempolicy
= NULL
;
932 * If DEBUG_MUTEXES is on, make sure we are holding no locks:
934 mutex_debug_check_no_locks_held(tsk
);
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);
967 task_t fastcall
*next_thread(const task_t
*p
)
969 return pid_task(p
->pids
[PIDTYPE_TGID
].pid_list
.next
, PIDTYPE_TGID
);
972 EXPORT_SYMBOL(next_thread
);
975 * Take down every thread in the group. This is called by fatal signals
976 * as well as by sys_exit_group (below).
979 do_group_exit(int exit_code
)
981 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
983 if (current
->signal
->flags
& SIGNAL_GROUP_EXIT
)
984 exit_code
= current
->signal
->group_exit_code
;
985 else if (!thread_group_empty(current
)) {
986 struct signal_struct
*const sig
= current
->signal
;
987 struct sighand_struct
*const sighand
= current
->sighand
;
988 read_lock(&tasklist_lock
);
989 spin_lock_irq(&sighand
->siglock
);
990 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
991 /* Another thread got here before we took the lock. */
992 exit_code
= sig
->group_exit_code
;
994 sig
->group_exit_code
= exit_code
;
995 zap_other_threads(current
);
997 spin_unlock_irq(&sighand
->siglock
);
998 read_unlock(&tasklist_lock
);
1006 * this kills every thread in the thread group. Note that any externally
1007 * wait4()-ing process will get the correct exit code - even if this
1008 * thread is not the thread group leader.
1010 asmlinkage
void sys_exit_group(int error_code
)
1012 do_group_exit((error_code
& 0xff) << 8);
1015 static int eligible_child(pid_t pid
, int options
, task_t
*p
)
1021 if (process_group(p
) != process_group(current
))
1023 } else if (pid
!= -1) {
1024 if (process_group(p
) != -pid
)
1029 * Do not consider detached threads that are
1032 if (p
->exit_signal
== -1 && !p
->ptrace
)
1035 /* Wait for all children (clone and not) if __WALL is set;
1036 * otherwise, wait for clone children *only* if __WCLONE is
1037 * set; otherwise, wait for non-clone children *only*. (Note:
1038 * A "clone" child here is one that reports to its parent
1039 * using a signal other than SIGCHLD.) */
1040 if (((p
->exit_signal
!= SIGCHLD
) ^ ((options
& __WCLONE
) != 0))
1041 && !(options
& __WALL
))
1044 * Do not consider thread group leaders that are
1045 * in a non-empty thread group:
1047 if (current
->tgid
!= p
->tgid
&& delay_group_leader(p
))
1050 if (security_task_wait(p
))
1056 static int wait_noreap_copyout(task_t
*p
, pid_t pid
, uid_t uid
,
1057 int why
, int status
,
1058 struct siginfo __user
*infop
,
1059 struct rusage __user
*rusagep
)
1061 int retval
= rusagep
? getrusage(p
, RUSAGE_BOTH
, rusagep
) : 0;
1064 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1066 retval
= put_user(0, &infop
->si_errno
);
1068 retval
= put_user((short)why
, &infop
->si_code
);
1070 retval
= put_user(pid
, &infop
->si_pid
);
1072 retval
= put_user(uid
, &infop
->si_uid
);
1074 retval
= put_user(status
, &infop
->si_status
);
1081 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1082 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1083 * the lock and this task is uninteresting. If we return nonzero, we have
1084 * released the lock and the system call should return.
1086 static int wait_task_zombie(task_t
*p
, int noreap
,
1087 struct siginfo __user
*infop
,
1088 int __user
*stat_addr
, struct rusage __user
*ru
)
1090 unsigned long state
;
1094 if (unlikely(noreap
)) {
1097 int exit_code
= p
->exit_code
;
1100 if (unlikely(p
->exit_state
!= EXIT_ZOMBIE
))
1102 if (unlikely(p
->exit_signal
== -1 && p
->ptrace
== 0))
1105 read_unlock(&tasklist_lock
);
1106 if ((exit_code
& 0x7f) == 0) {
1108 status
= exit_code
>> 8;
1110 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1111 status
= exit_code
& 0x7f;
1113 return wait_noreap_copyout(p
, pid
, uid
, why
,
1118 * Try to move the task's state to DEAD
1119 * only one thread is allowed to do this:
1121 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1122 if (state
!= EXIT_ZOMBIE
) {
1123 BUG_ON(state
!= EXIT_DEAD
);
1126 if (unlikely(p
->exit_signal
== -1 && p
->ptrace
== 0)) {
1128 * This can only happen in a race with a ptraced thread
1129 * dying on another processor.
1134 if (likely(p
->real_parent
== p
->parent
) && likely(p
->signal
)) {
1135 struct signal_struct
*psig
;
1136 struct signal_struct
*sig
;
1139 * The resource counters for the group leader are in its
1140 * own task_struct. Those for dead threads in the group
1141 * are in its signal_struct, as are those for the child
1142 * processes it has previously reaped. All these
1143 * accumulate in the parent's signal_struct c* fields.
1145 * We don't bother to take a lock here to protect these
1146 * p->signal fields, because they are only touched by
1147 * __exit_signal, which runs with tasklist_lock
1148 * write-locked anyway, and so is excluded here. We do
1149 * need to protect the access to p->parent->signal fields,
1150 * as other threads in the parent group can be right
1151 * here reaping other children at the same time.
1153 spin_lock_irq(&p
->parent
->sighand
->siglock
);
1154 psig
= p
->parent
->signal
;
1157 cputime_add(psig
->cutime
,
1158 cputime_add(p
->utime
,
1159 cputime_add(sig
->utime
,
1162 cputime_add(psig
->cstime
,
1163 cputime_add(p
->stime
,
1164 cputime_add(sig
->stime
,
1167 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1169 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1171 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1173 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1174 spin_unlock_irq(&p
->parent
->sighand
->siglock
);
1178 * Now we are sure this task is interesting, and no other
1179 * thread can reap it because we set its state to EXIT_DEAD.
1181 read_unlock(&tasklist_lock
);
1183 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1184 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1185 ? p
->signal
->group_exit_code
: p
->exit_code
;
1186 if (!retval
&& stat_addr
)
1187 retval
= put_user(status
, stat_addr
);
1188 if (!retval
&& infop
)
1189 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1190 if (!retval
&& infop
)
1191 retval
= put_user(0, &infop
->si_errno
);
1192 if (!retval
&& infop
) {
1195 if ((status
& 0x7f) == 0) {
1199 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1202 retval
= put_user((short)why
, &infop
->si_code
);
1204 retval
= put_user(status
, &infop
->si_status
);
1206 if (!retval
&& infop
)
1207 retval
= put_user(p
->pid
, &infop
->si_pid
);
1208 if (!retval
&& infop
)
1209 retval
= put_user(p
->uid
, &infop
->si_uid
);
1211 // TODO: is this safe?
1212 p
->exit_state
= EXIT_ZOMBIE
;
1216 if (p
->real_parent
!= p
->parent
) {
1217 write_lock_irq(&tasklist_lock
);
1218 /* Double-check with lock held. */
1219 if (p
->real_parent
!= p
->parent
) {
1221 // TODO: is this safe?
1222 p
->exit_state
= EXIT_ZOMBIE
;
1224 * If this is not a detached task, notify the parent.
1225 * If it's still not detached after that, don't release
1228 if (p
->exit_signal
!= -1) {
1229 do_notify_parent(p
, p
->exit_signal
);
1230 if (p
->exit_signal
!= -1)
1234 write_unlock_irq(&tasklist_lock
);
1243 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1244 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1245 * the lock and this task is uninteresting. If we return nonzero, we have
1246 * released the lock and the system call should return.
1248 static int wait_task_stopped(task_t
*p
, int delayed_group_leader
, int noreap
,
1249 struct siginfo __user
*infop
,
1250 int __user
*stat_addr
, struct rusage __user
*ru
)
1252 int retval
, exit_code
;
1256 if (delayed_group_leader
&& !(p
->ptrace
& PT_PTRACED
) &&
1257 p
->signal
&& p
->signal
->group_stop_count
> 0)
1259 * A group stop is in progress and this is the group leader.
1260 * We won't report until all threads have stopped.
1265 * Now we are pretty sure this task is interesting.
1266 * Make sure it doesn't get reaped out from under us while we
1267 * give up the lock and then examine it below. We don't want to
1268 * keep holding onto the tasklist_lock while we call getrusage and
1269 * possibly take page faults for user memory.
1272 read_unlock(&tasklist_lock
);
1274 if (unlikely(noreap
)) {
1277 int why
= (p
->ptrace
& PT_PTRACED
) ? CLD_TRAPPED
: CLD_STOPPED
;
1279 exit_code
= p
->exit_code
;
1280 if (unlikely(!exit_code
) ||
1281 unlikely(p
->state
& TASK_TRACED
))
1283 return wait_noreap_copyout(p
, pid
, uid
,
1284 why
, (exit_code
<< 8) | 0x7f,
1288 write_lock_irq(&tasklist_lock
);
1291 * This uses xchg to be atomic with the thread resuming and setting
1292 * it. It must also be done with the write lock held to prevent a
1293 * race with the EXIT_ZOMBIE case.
1295 exit_code
= xchg(&p
->exit_code
, 0);
1296 if (unlikely(p
->exit_state
)) {
1298 * The task resumed and then died. Let the next iteration
1299 * catch it in EXIT_ZOMBIE. Note that exit_code might
1300 * already be zero here if it resumed and did _exit(0).
1301 * The task itself is dead and won't touch exit_code again;
1302 * other processors in this function are locked out.
1304 p
->exit_code
= exit_code
;
1307 if (unlikely(exit_code
== 0)) {
1309 * Another thread in this function got to it first, or it
1310 * resumed, or it resumed and then died.
1312 write_unlock_irq(&tasklist_lock
);
1316 * We are returning to the wait loop without having successfully
1317 * removed the process and having released the lock. We cannot
1318 * continue, since the "p" task pointer is potentially stale.
1320 * Return -EAGAIN, and do_wait() will restart the loop from the
1321 * beginning. Do _not_ re-acquire the lock.
1326 /* move to end of parent's list to avoid starvation */
1330 write_unlock_irq(&tasklist_lock
);
1332 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1333 if (!retval
&& stat_addr
)
1334 retval
= put_user((exit_code
<< 8) | 0x7f, stat_addr
);
1335 if (!retval
&& infop
)
1336 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1337 if (!retval
&& infop
)
1338 retval
= put_user(0, &infop
->si_errno
);
1339 if (!retval
&& infop
)
1340 retval
= put_user((short)((p
->ptrace
& PT_PTRACED
)
1341 ? CLD_TRAPPED
: CLD_STOPPED
),
1343 if (!retval
&& infop
)
1344 retval
= put_user(exit_code
, &infop
->si_status
);
1345 if (!retval
&& infop
)
1346 retval
= put_user(p
->pid
, &infop
->si_pid
);
1347 if (!retval
&& infop
)
1348 retval
= put_user(p
->uid
, &infop
->si_uid
);
1358 * Handle do_wait work for one task in a live, non-stopped state.
1359 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1360 * the lock and this task is uninteresting. If we return nonzero, we have
1361 * released the lock and the system call should return.
1363 static int wait_task_continued(task_t
*p
, int noreap
,
1364 struct siginfo __user
*infop
,
1365 int __user
*stat_addr
, struct rusage __user
*ru
)
1371 if (unlikely(!p
->signal
))
1374 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1377 spin_lock_irq(&p
->sighand
->siglock
);
1378 /* Re-check with the lock held. */
1379 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1380 spin_unlock_irq(&p
->sighand
->siglock
);
1384 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1385 spin_unlock_irq(&p
->sighand
->siglock
);
1390 read_unlock(&tasklist_lock
);
1393 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1395 if (!retval
&& stat_addr
)
1396 retval
= put_user(0xffff, stat_addr
);
1400 retval
= wait_noreap_copyout(p
, pid
, uid
,
1401 CLD_CONTINUED
, SIGCONT
,
1403 BUG_ON(retval
== 0);
1410 static inline int my_ptrace_child(struct task_struct
*p
)
1412 if (!(p
->ptrace
& PT_PTRACED
))
1414 if (!(p
->ptrace
& PT_ATTACHED
))
1417 * This child was PTRACE_ATTACH'd. We should be seeing it only if
1418 * we are the attacher. If we are the real parent, this is a race
1419 * inside ptrace_attach. It is waiting for the tasklist_lock,
1420 * which we have to switch the parent links, but has already set
1421 * the flags in p->ptrace.
1423 return (p
->parent
!= p
->real_parent
);
1426 static long do_wait(pid_t pid
, int options
, struct siginfo __user
*infop
,
1427 int __user
*stat_addr
, struct rusage __user
*ru
)
1429 DECLARE_WAITQUEUE(wait
, current
);
1430 struct task_struct
*tsk
;
1433 add_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1436 * We will set this flag if we see any child that might later
1437 * match our criteria, even if we are not able to reap it yet.
1440 current
->state
= TASK_INTERRUPTIBLE
;
1441 read_lock(&tasklist_lock
);
1444 struct task_struct
*p
;
1445 struct list_head
*_p
;
1448 list_for_each(_p
,&tsk
->children
) {
1449 p
= list_entry(_p
,struct task_struct
,sibling
);
1451 ret
= eligible_child(pid
, options
, p
);
1458 * When we hit the race with PTRACE_ATTACH,
1459 * we will not report this child. But the
1460 * race means it has not yet been moved to
1461 * our ptrace_children list, so we need to
1462 * set the flag here to avoid a spurious ECHILD
1463 * when the race happens with the only child.
1466 if (!my_ptrace_child(p
))
1471 * It's stopped now, so it might later
1472 * continue, exit, or stop again.
1475 if (!(options
& WUNTRACED
) &&
1476 !my_ptrace_child(p
))
1478 retval
= wait_task_stopped(p
, ret
== 2,
1479 (options
& WNOWAIT
),
1482 if (retval
== -EAGAIN
)
1484 if (retval
!= 0) /* He released the lock. */
1489 if (p
->exit_state
== EXIT_DEAD
)
1491 // case EXIT_ZOMBIE:
1492 if (p
->exit_state
== EXIT_ZOMBIE
) {
1494 * Eligible but we cannot release
1498 goto check_continued
;
1499 if (!likely(options
& WEXITED
))
1501 retval
= wait_task_zombie(
1502 p
, (options
& WNOWAIT
),
1503 infop
, stat_addr
, ru
);
1504 /* He released the lock. */
1511 * It's running now, so it might later
1512 * exit, stop, or stop and then continue.
1515 if (!unlikely(options
& WCONTINUED
))
1517 retval
= wait_task_continued(
1518 p
, (options
& WNOWAIT
),
1519 infop
, stat_addr
, ru
);
1520 if (retval
!= 0) /* He released the lock. */
1526 list_for_each(_p
, &tsk
->ptrace_children
) {
1527 p
= list_entry(_p
, struct task_struct
,
1529 if (!eligible_child(pid
, options
, p
))
1535 if (options
& __WNOTHREAD
)
1537 tsk
= next_thread(tsk
);
1538 if (tsk
->signal
!= current
->signal
)
1540 } while (tsk
!= current
);
1542 read_unlock(&tasklist_lock
);
1545 if (options
& WNOHANG
)
1547 retval
= -ERESTARTSYS
;
1548 if (signal_pending(current
))
1555 current
->state
= TASK_RUNNING
;
1556 remove_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1562 * For a WNOHANG return, clear out all the fields
1563 * we would set so the user can easily tell the
1567 retval
= put_user(0, &infop
->si_signo
);
1569 retval
= put_user(0, &infop
->si_errno
);
1571 retval
= put_user(0, &infop
->si_code
);
1573 retval
= put_user(0, &infop
->si_pid
);
1575 retval
= put_user(0, &infop
->si_uid
);
1577 retval
= put_user(0, &infop
->si_status
);
1583 asmlinkage
long sys_waitid(int which
, pid_t pid
,
1584 struct siginfo __user
*infop
, int options
,
1585 struct rusage __user
*ru
)
1589 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1591 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1611 ret
= do_wait(pid
, options
, infop
, NULL
, ru
);
1613 /* avoid REGPARM breakage on x86: */
1614 prevent_tail_call(ret
);
1618 asmlinkage
long sys_wait4(pid_t pid
, int __user
*stat_addr
,
1619 int options
, struct rusage __user
*ru
)
1623 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1624 __WNOTHREAD
|__WCLONE
|__WALL
))
1626 ret
= do_wait(pid
, options
| WEXITED
, NULL
, stat_addr
, ru
);
1628 /* avoid REGPARM breakage on x86: */
1629 prevent_tail_call(ret
);
1633 #ifdef __ARCH_WANT_SYS_WAITPID
1636 * sys_waitpid() remains for compatibility. waitpid() should be
1637 * implemented by calling sys_wait4() from libc.a.
1639 asmlinkage
long sys_waitpid(pid_t pid
, int __user
*stat_addr
, int options
)
1641 return sys_wait4(pid
, stat_addr
, options
, NULL
);