4 * Copyright (C) 1991, 1992 Linus Torvalds
8 #include <linux/slab.h>
9 #include <linux/interrupt.h>
10 #include <linux/module.h>
11 #include <linux/capability.h>
12 #include <linux/completion.h>
13 #include <linux/personality.h>
14 #include <linux/tty.h>
15 #include <linux/mnt_namespace.h>
16 #include <linux/iocontext.h>
17 #include <linux/key.h>
18 #include <linux/security.h>
19 #include <linux/cpu.h>
20 #include <linux/acct.h>
21 #include <linux/tsacct_kern.h>
22 #include <linux/file.h>
23 #include <linux/fdtable.h>
24 #include <linux/binfmts.h>
25 #include <linux/nsproxy.h>
26 #include <linux/pid_namespace.h>
27 #include <linux/ptrace.h>
28 #include <linux/profile.h>
29 #include <linux/mount.h>
30 #include <linux/proc_fs.h>
31 #include <linux/kthread.h>
32 #include <linux/mempolicy.h>
33 #include <linux/taskstats_kern.h>
34 #include <linux/delayacct.h>
35 #include <linux/freezer.h>
36 #include <linux/cgroup.h>
37 #include <linux/syscalls.h>
38 #include <linux/signal.h>
39 #include <linux/posix-timers.h>
40 #include <linux/cn_proc.h>
41 #include <linux/mutex.h>
42 #include <linux/futex.h>
43 #include <linux/pipe_fs_i.h>
44 #include <linux/audit.h> /* for audit_free() */
45 #include <linux/resource.h>
46 #include <linux/blkdev.h>
47 #include <linux/task_io_accounting_ops.h>
48 #include <linux/tracehook.h>
49 #include <linux/init_task.h>
50 #include <trace/sched.h>
52 #include <asm/uaccess.h>
53 #include <asm/unistd.h>
54 #include <asm/pgtable.h>
55 #include <asm/mmu_context.h>
56 #include "cred-internals.h"
58 DEFINE_TRACE(sched_process_free
);
59 DEFINE_TRACE(sched_process_exit
);
60 DEFINE_TRACE(sched_process_wait
);
62 static void exit_mm(struct task_struct
* tsk
);
64 static void __unhash_process(struct task_struct
*p
)
67 detach_pid(p
, PIDTYPE_PID
);
68 if (thread_group_leader(p
)) {
69 detach_pid(p
, PIDTYPE_PGID
);
70 detach_pid(p
, PIDTYPE_SID
);
72 list_del_rcu(&p
->tasks
);
73 __get_cpu_var(process_counts
)--;
75 list_del_rcu(&p
->thread_group
);
76 list_del_init(&p
->sibling
);
80 * This function expects the tasklist_lock write-locked.
82 static void __exit_signal(struct task_struct
*tsk
)
84 struct signal_struct
*sig
= tsk
->signal
;
85 struct sighand_struct
*sighand
;
88 BUG_ON(!atomic_read(&sig
->count
));
90 sighand
= rcu_dereference(tsk
->sighand
);
91 spin_lock(&sighand
->siglock
);
93 posix_cpu_timers_exit(tsk
);
94 if (atomic_dec_and_test(&sig
->count
))
95 posix_cpu_timers_exit_group(tsk
);
98 * If there is any task waiting for the group exit
101 if (sig
->group_exit_task
&& atomic_read(&sig
->count
) == sig
->notify_count
)
102 wake_up_process(sig
->group_exit_task
);
104 if (tsk
== sig
->curr_target
)
105 sig
->curr_target
= next_thread(tsk
);
107 * Accumulate here the counters for all threads but the
108 * group leader as they die, so they can be added into
109 * the process-wide totals when those are taken.
110 * The group leader stays around as a zombie as long
111 * as there are other threads. When it gets reaped,
112 * the exit.c code will add its counts into these totals.
113 * We won't ever get here for the group leader, since it
114 * will have been the last reference on the signal_struct.
116 sig
->utime
= cputime_add(sig
->utime
, task_utime(tsk
));
117 sig
->stime
= cputime_add(sig
->stime
, task_stime(tsk
));
118 sig
->gtime
= cputime_add(sig
->gtime
, task_gtime(tsk
));
119 sig
->min_flt
+= tsk
->min_flt
;
120 sig
->maj_flt
+= tsk
->maj_flt
;
121 sig
->nvcsw
+= tsk
->nvcsw
;
122 sig
->nivcsw
+= tsk
->nivcsw
;
123 sig
->inblock
+= task_io_get_inblock(tsk
);
124 sig
->oublock
+= task_io_get_oublock(tsk
);
125 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
126 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
127 sig
= NULL
; /* Marker for below. */
130 __unhash_process(tsk
);
133 * Do this under ->siglock, we can race with another thread
134 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
136 flush_sigqueue(&tsk
->pending
);
140 spin_unlock(&sighand
->siglock
);
142 __cleanup_sighand(sighand
);
143 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
145 flush_sigqueue(&sig
->shared_pending
);
146 taskstats_tgid_free(sig
);
148 * Make sure ->signal can't go away under rq->lock,
149 * see account_group_exec_runtime().
151 task_rq_unlock_wait(tsk
);
152 __cleanup_signal(sig
);
156 static void delayed_put_task_struct(struct rcu_head
*rhp
)
158 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
160 trace_sched_process_free(tsk
);
161 put_task_struct(tsk
);
165 void release_task(struct task_struct
* p
)
167 struct task_struct
*leader
;
170 tracehook_prepare_release_task(p
);
171 /* don't need to get the RCU readlock here - the process is dead and
172 * can't be modifying its own credentials */
173 atomic_dec(&__task_cred(p
)->user
->processes
);
176 write_lock_irq(&tasklist_lock
);
177 tracehook_finish_release_task(p
);
181 * If we are the last non-leader member of the thread
182 * group, and the leader is zombie, then notify the
183 * group leader's parent process. (if it wants notification.)
186 leader
= p
->group_leader
;
187 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
188 BUG_ON(task_detached(leader
));
189 do_notify_parent(leader
, leader
->exit_signal
);
191 * If we were the last child thread and the leader has
192 * exited already, and the leader's parent ignores SIGCHLD,
193 * then we are the one who should release the leader.
195 * do_notify_parent() will have marked it self-reaping in
198 zap_leader
= task_detached(leader
);
201 * This maintains the invariant that release_task()
202 * only runs on a task in EXIT_DEAD, just for sanity.
205 leader
->exit_state
= EXIT_DEAD
;
208 write_unlock_irq(&tasklist_lock
);
210 call_rcu(&p
->rcu
, delayed_put_task_struct
);
213 if (unlikely(zap_leader
))
218 * This checks not only the pgrp, but falls back on the pid if no
219 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
222 * The caller must hold rcu lock or the tasklist lock.
224 struct pid
*session_of_pgrp(struct pid
*pgrp
)
226 struct task_struct
*p
;
227 struct pid
*sid
= NULL
;
229 p
= pid_task(pgrp
, PIDTYPE_PGID
);
231 p
= pid_task(pgrp
, PIDTYPE_PID
);
233 sid
= task_session(p
);
239 * Determine if a process group is "orphaned", according to the POSIX
240 * definition in 2.2.2.52. Orphaned process groups are not to be affected
241 * by terminal-generated stop signals. Newly orphaned process groups are
242 * to receive a SIGHUP and a SIGCONT.
244 * "I ask you, have you ever known what it is to be an orphan?"
246 static int will_become_orphaned_pgrp(struct pid
*pgrp
, struct task_struct
*ignored_task
)
248 struct task_struct
*p
;
250 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
251 if ((p
== ignored_task
) ||
252 (p
->exit_state
&& thread_group_empty(p
)) ||
253 is_global_init(p
->real_parent
))
256 if (task_pgrp(p
->real_parent
) != pgrp
&&
257 task_session(p
->real_parent
) == task_session(p
))
259 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
264 int is_current_pgrp_orphaned(void)
268 read_lock(&tasklist_lock
);
269 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
270 read_unlock(&tasklist_lock
);
275 static int has_stopped_jobs(struct pid
*pgrp
)
278 struct task_struct
*p
;
280 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
281 if (!task_is_stopped(p
))
285 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
290 * Check to see if any process groups have become orphaned as
291 * a result of our exiting, and if they have any stopped jobs,
292 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
295 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
297 struct pid
*pgrp
= task_pgrp(tsk
);
298 struct task_struct
*ignored_task
= tsk
;
301 /* exit: our father is in a different pgrp than
302 * we are and we were the only connection outside.
304 parent
= tsk
->real_parent
;
306 /* reparent: our child is in a different pgrp than
307 * we are, and it was the only connection outside.
311 if (task_pgrp(parent
) != pgrp
&&
312 task_session(parent
) == task_session(tsk
) &&
313 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
314 has_stopped_jobs(pgrp
)) {
315 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
316 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
321 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
323 * If a kernel thread is launched as a result of a system call, or if
324 * it ever exits, it should generally reparent itself to kthreadd so it
325 * isn't in the way of other processes and is correctly cleaned up on exit.
327 * The various task state such as scheduling policy and priority may have
328 * been inherited from a user process, so we reset them to sane values here.
330 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
332 static void reparent_to_kthreadd(void)
334 write_lock_irq(&tasklist_lock
);
336 ptrace_unlink(current
);
337 /* Reparent to init */
338 current
->real_parent
= current
->parent
= kthreadd_task
;
339 list_move_tail(¤t
->sibling
, ¤t
->real_parent
->children
);
341 /* Set the exit signal to SIGCHLD so we signal init on exit */
342 current
->exit_signal
= SIGCHLD
;
344 if (task_nice(current
) < 0)
345 set_user_nice(current
, 0);
349 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
350 sizeof(current
->signal
->rlim
));
352 atomic_inc(&init_cred
.usage
);
353 commit_creds(&init_cred
);
354 write_unlock_irq(&tasklist_lock
);
357 void __set_special_pids(struct pid
*pid
)
359 struct task_struct
*curr
= current
->group_leader
;
361 if (task_session(curr
) != pid
)
362 change_pid(curr
, PIDTYPE_SID
, pid
);
364 if (task_pgrp(curr
) != pid
)
365 change_pid(curr
, PIDTYPE_PGID
, pid
);
368 static void set_special_pids(struct pid
*pid
)
370 write_lock_irq(&tasklist_lock
);
371 __set_special_pids(pid
);
372 write_unlock_irq(&tasklist_lock
);
376 * Let kernel threads use this to say that they
377 * allow a certain signal (since daemonize() will
378 * have disabled all of them by default).
380 int allow_signal(int sig
)
382 if (!valid_signal(sig
) || sig
< 1)
385 spin_lock_irq(¤t
->sighand
->siglock
);
386 sigdelset(¤t
->blocked
, sig
);
388 /* Kernel threads handle their own signals.
389 Let the signal code know it'll be handled, so
390 that they don't get converted to SIGKILL or
391 just silently dropped */
392 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
395 spin_unlock_irq(¤t
->sighand
->siglock
);
399 EXPORT_SYMBOL(allow_signal
);
401 int disallow_signal(int sig
)
403 if (!valid_signal(sig
) || sig
< 1)
406 spin_lock_irq(¤t
->sighand
->siglock
);
407 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= SIG_IGN
;
409 spin_unlock_irq(¤t
->sighand
->siglock
);
413 EXPORT_SYMBOL(disallow_signal
);
416 * Put all the gunge required to become a kernel thread without
417 * attached user resources in one place where it belongs.
420 void daemonize(const char *name
, ...)
423 struct fs_struct
*fs
;
426 va_start(args
, name
);
427 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
431 * If we were started as result of loading a module, close all of the
432 * user space pages. We don't need them, and if we didn't close them
433 * they would be locked into memory.
437 * We don't want to have TIF_FREEZE set if the system-wide hibernation
438 * or suspend transition begins right now.
440 current
->flags
|= (PF_NOFREEZE
| PF_KTHREAD
);
442 if (current
->nsproxy
!= &init_nsproxy
) {
443 get_nsproxy(&init_nsproxy
);
444 switch_task_namespaces(current
, &init_nsproxy
);
446 set_special_pids(&init_struct_pid
);
447 proc_clear_tty(current
);
449 /* Block and flush all signals */
450 sigfillset(&blocked
);
451 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
452 flush_signals(current
);
454 /* Become as one with the init task */
456 exit_fs(current
); /* current->fs->count--; */
459 atomic_inc(&fs
->count
);
462 current
->files
= init_task
.files
;
463 atomic_inc(¤t
->files
->count
);
465 reparent_to_kthreadd();
468 EXPORT_SYMBOL(daemonize
);
470 static void close_files(struct files_struct
* files
)
478 * It is safe to dereference the fd table without RCU or
479 * ->file_lock because this is the last reference to the
482 fdt
= files_fdtable(files
);
486 if (i
>= fdt
->max_fds
)
488 set
= fdt
->open_fds
->fds_bits
[j
++];
491 struct file
* file
= xchg(&fdt
->fd
[i
], NULL
);
493 filp_close(file
, files
);
503 struct files_struct
*get_files_struct(struct task_struct
*task
)
505 struct files_struct
*files
;
510 atomic_inc(&files
->count
);
516 void put_files_struct(struct files_struct
*files
)
520 if (atomic_dec_and_test(&files
->count
)) {
523 * Free the fd and fdset arrays if we expanded them.
524 * If the fdtable was embedded, pass files for freeing
525 * at the end of the RCU grace period. Otherwise,
526 * you can free files immediately.
528 fdt
= files_fdtable(files
);
529 if (fdt
!= &files
->fdtab
)
530 kmem_cache_free(files_cachep
, files
);
535 void reset_files_struct(struct files_struct
*files
)
537 struct task_struct
*tsk
= current
;
538 struct files_struct
*old
;
544 put_files_struct(old
);
547 void exit_files(struct task_struct
*tsk
)
549 struct files_struct
* files
= tsk
->files
;
555 put_files_struct(files
);
559 void put_fs_struct(struct fs_struct
*fs
)
561 /* No need to hold fs->lock if we are killing it */
562 if (atomic_dec_and_test(&fs
->count
)) {
565 kmem_cache_free(fs_cachep
, fs
);
569 void exit_fs(struct task_struct
*tsk
)
571 struct fs_struct
* fs
= tsk
->fs
;
581 EXPORT_SYMBOL_GPL(exit_fs
);
583 #ifdef CONFIG_MM_OWNER
585 * Task p is exiting and it owned mm, lets find a new owner for it
588 mm_need_new_owner(struct mm_struct
*mm
, struct task_struct
*p
)
591 * If there are other users of the mm and the owner (us) is exiting
592 * we need to find a new owner to take on the responsibility.
594 if (atomic_read(&mm
->mm_users
) <= 1)
601 void mm_update_next_owner(struct mm_struct
*mm
)
603 struct task_struct
*c
, *g
, *p
= current
;
606 if (!mm_need_new_owner(mm
, p
))
609 read_lock(&tasklist_lock
);
611 * Search in the children
613 list_for_each_entry(c
, &p
->children
, sibling
) {
615 goto assign_new_owner
;
619 * Search in the siblings
621 list_for_each_entry(c
, &p
->parent
->children
, sibling
) {
623 goto assign_new_owner
;
627 * Search through everything else. We should not get
630 do_each_thread(g
, c
) {
632 goto assign_new_owner
;
633 } while_each_thread(g
, c
);
635 read_unlock(&tasklist_lock
);
637 * We found no owner yet mm_users > 1: this implies that we are
638 * most likely racing with swapoff (try_to_unuse()) or /proc or
639 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
648 * The task_lock protects c->mm from changing.
649 * We always want mm->owner->mm == mm
653 * Delay read_unlock() till we have the task_lock()
654 * to ensure that c does not slip away underneath us
656 read_unlock(&tasklist_lock
);
666 #endif /* CONFIG_MM_OWNER */
669 * Turn us into a lazy TLB process if we
672 static void exit_mm(struct task_struct
* tsk
)
674 struct mm_struct
*mm
= tsk
->mm
;
675 struct core_state
*core_state
;
681 * Serialize with any possible pending coredump.
682 * We must hold mmap_sem around checking core_state
683 * and clearing tsk->mm. The core-inducing thread
684 * will increment ->nr_threads for each thread in the
685 * group with ->mm != NULL.
687 down_read(&mm
->mmap_sem
);
688 core_state
= mm
->core_state
;
690 struct core_thread self
;
691 up_read(&mm
->mmap_sem
);
694 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
696 * Implies mb(), the result of xchg() must be visible
697 * to core_state->dumper.
699 if (atomic_dec_and_test(&core_state
->nr_threads
))
700 complete(&core_state
->startup
);
703 set_task_state(tsk
, TASK_UNINTERRUPTIBLE
);
704 if (!self
.task
) /* see coredump_finish() */
708 __set_task_state(tsk
, TASK_RUNNING
);
709 down_read(&mm
->mmap_sem
);
711 atomic_inc(&mm
->mm_count
);
712 BUG_ON(mm
!= tsk
->active_mm
);
713 /* more a memory barrier than a real lock */
716 up_read(&mm
->mmap_sem
);
717 enter_lazy_tlb(mm
, current
);
718 /* We don't want this task to be frozen prematurely */
719 clear_freeze_flag(tsk
);
721 mm_update_next_owner(mm
);
726 * When we die, we re-parent all our children.
727 * Try to give them to another thread in our thread
728 * group, and if no such member exists, give it to
729 * the child reaper process (ie "init") in our pid
732 static struct task_struct
*find_new_reaper(struct task_struct
*father
)
734 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
735 struct task_struct
*thread
;
738 while_each_thread(father
, thread
) {
739 if (thread
->flags
& PF_EXITING
)
741 if (unlikely(pid_ns
->child_reaper
== father
))
742 pid_ns
->child_reaper
= thread
;
746 if (unlikely(pid_ns
->child_reaper
== father
)) {
747 write_unlock_irq(&tasklist_lock
);
748 if (unlikely(pid_ns
== &init_pid_ns
))
749 panic("Attempted to kill init!");
751 zap_pid_ns_processes(pid_ns
);
752 write_lock_irq(&tasklist_lock
);
754 * We can not clear ->child_reaper or leave it alone.
755 * There may by stealth EXIT_DEAD tasks on ->children,
756 * forget_original_parent() must move them somewhere.
758 pid_ns
->child_reaper
= init_pid_ns
.child_reaper
;
761 return pid_ns
->child_reaper
;
765 * Any that need to be release_task'd are put on the @dead list.
767 static void reparent_thread(struct task_struct
*father
, struct task_struct
*p
,
768 struct list_head
*dead
)
770 if (p
->pdeath_signal
)
771 group_send_sig_info(p
->pdeath_signal
, SEND_SIG_NOINFO
, p
);
773 list_move_tail(&p
->sibling
, &p
->real_parent
->children
);
775 if (task_detached(p
))
778 * If this is a threaded reparent there is no need to
779 * notify anyone anything has happened.
781 if (same_thread_group(p
->real_parent
, father
))
784 /* We don't want people slaying init. */
785 p
->exit_signal
= SIGCHLD
;
787 /* If it has exited notify the new parent about this child's death. */
789 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
790 do_notify_parent(p
, p
->exit_signal
);
791 if (task_detached(p
)) {
792 p
->exit_state
= EXIT_DEAD
;
793 list_move_tail(&p
->sibling
, dead
);
797 kill_orphaned_pgrp(p
, father
);
800 static void forget_original_parent(struct task_struct
*father
)
802 struct task_struct
*p
, *n
, *reaper
;
803 LIST_HEAD(dead_children
);
807 write_lock_irq(&tasklist_lock
);
808 reaper
= find_new_reaper(father
);
810 list_for_each_entry_safe(p
, n
, &father
->children
, sibling
) {
811 p
->real_parent
= reaper
;
812 if (p
->parent
== father
) {
814 p
->parent
= p
->real_parent
;
816 reparent_thread(father
, p
, &dead_children
);
818 write_unlock_irq(&tasklist_lock
);
820 BUG_ON(!list_empty(&father
->children
));
822 list_for_each_entry_safe(p
, n
, &dead_children
, sibling
) {
823 list_del_init(&p
->sibling
);
829 * Send signals to all our closest relatives so that they know
830 * to properly mourn us..
832 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
838 * This does two things:
840 * A. Make init inherit all the child processes
841 * B. Check to see if any process groups have become orphaned
842 * as a result of our exiting, and if they have any stopped
843 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
845 forget_original_parent(tsk
);
846 exit_task_namespaces(tsk
);
848 write_lock_irq(&tasklist_lock
);
850 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
852 /* Let father know we died
854 * Thread signals are configurable, but you aren't going to use
855 * that to send signals to arbitary processes.
856 * That stops right now.
858 * If the parent exec id doesn't match the exec id we saved
859 * when we started then we know the parent has changed security
862 * If our self_exec id doesn't match our parent_exec_id then
863 * we have changed execution domain as these two values started
864 * the same after a fork.
866 if (tsk
->exit_signal
!= SIGCHLD
&& !task_detached(tsk
) &&
867 (tsk
->parent_exec_id
!= tsk
->real_parent
->self_exec_id
||
868 tsk
->self_exec_id
!= tsk
->parent_exec_id
) &&
870 tsk
->exit_signal
= SIGCHLD
;
872 signal
= tracehook_notify_death(tsk
, &cookie
, group_dead
);
874 signal
= do_notify_parent(tsk
, signal
);
876 tsk
->exit_state
= signal
== DEATH_REAP
? EXIT_DEAD
: EXIT_ZOMBIE
;
878 /* mt-exec, de_thread() is waiting for us */
879 if (thread_group_leader(tsk
) &&
880 tsk
->signal
->group_exit_task
&&
881 tsk
->signal
->notify_count
< 0)
882 wake_up_process(tsk
->signal
->group_exit_task
);
884 write_unlock_irq(&tasklist_lock
);
886 tracehook_report_death(tsk
, signal
, cookie
, group_dead
);
888 /* If the process is dead, release it - nobody will wait for it */
889 if (signal
== DEATH_REAP
)
893 #ifdef CONFIG_DEBUG_STACK_USAGE
894 static void check_stack_usage(void)
896 static DEFINE_SPINLOCK(low_water_lock
);
897 static int lowest_to_date
= THREAD_SIZE
;
900 free
= stack_not_used(current
);
902 if (free
>= lowest_to_date
)
905 spin_lock(&low_water_lock
);
906 if (free
< lowest_to_date
) {
907 printk(KERN_WARNING
"%s used greatest stack depth: %lu bytes "
909 current
->comm
, free
);
910 lowest_to_date
= free
;
912 spin_unlock(&low_water_lock
);
915 static inline void check_stack_usage(void) {}
918 NORET_TYPE
void do_exit(long code
)
920 struct task_struct
*tsk
= current
;
923 profile_task_exit(tsk
);
925 WARN_ON(atomic_read(&tsk
->fs_excl
));
927 if (unlikely(in_interrupt()))
928 panic("Aiee, killing interrupt handler!");
929 if (unlikely(!tsk
->pid
))
930 panic("Attempted to kill the idle task!");
932 tracehook_report_exit(&code
);
935 * We're taking recursive faults here in do_exit. Safest is to just
936 * leave this task alone and wait for reboot.
938 if (unlikely(tsk
->flags
& PF_EXITING
)) {
940 "Fixing recursive fault but reboot is needed!\n");
942 * We can do this unlocked here. The futex code uses
943 * this flag just to verify whether the pi state
944 * cleanup has been done or not. In the worst case it
945 * loops once more. We pretend that the cleanup was
946 * done as there is no way to return. Either the
947 * OWNER_DIED bit is set by now or we push the blocked
948 * task into the wait for ever nirwana as well.
950 tsk
->flags
|= PF_EXITPIDONE
;
951 set_current_state(TASK_UNINTERRUPTIBLE
);
955 exit_signals(tsk
); /* sets PF_EXITING */
957 * tsk->flags are checked in the futex code to protect against
958 * an exiting task cleaning up the robust pi futexes.
961 spin_unlock_wait(&tsk
->pi_lock
);
963 if (unlikely(in_atomic()))
964 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
965 current
->comm
, task_pid_nr(current
),
968 acct_update_integrals(tsk
);
970 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
972 hrtimer_cancel(&tsk
->signal
->real_timer
);
973 exit_itimers(tsk
->signal
);
975 acct_collect(code
, group_dead
);
978 if (unlikely(tsk
->audit_context
))
981 tsk
->exit_code
= code
;
982 taskstats_exit(tsk
, group_dead
);
988 trace_sched_process_exit(tsk
);
997 if (group_dead
&& tsk
->signal
->leader
)
998 disassociate_ctty(1);
1000 module_put(task_thread_info(tsk
)->exec_domain
->module
);
1002 module_put(tsk
->binfmt
->module
);
1004 proc_exit_connector(tsk
);
1005 exit_notify(tsk
, group_dead
);
1007 mpol_put(tsk
->mempolicy
);
1008 tsk
->mempolicy
= NULL
;
1012 * This must happen late, after the PID is not
1015 if (unlikely(!list_empty(&tsk
->pi_state_list
)))
1016 exit_pi_state_list(tsk
);
1017 if (unlikely(current
->pi_state_cache
))
1018 kfree(current
->pi_state_cache
);
1021 * Make sure we are holding no locks:
1023 debug_check_no_locks_held(tsk
);
1025 * We can do this unlocked here. The futex code uses this flag
1026 * just to verify whether the pi state cleanup has been done
1027 * or not. In the worst case it loops once more.
1029 tsk
->flags
|= PF_EXITPIDONE
;
1031 if (tsk
->io_context
)
1034 if (tsk
->splice_pipe
)
1035 __free_pipe_info(tsk
->splice_pipe
);
1038 /* causes final put_task_struct in finish_task_switch(). */
1039 tsk
->state
= TASK_DEAD
;
1042 /* Avoid "noreturn function does return". */
1044 cpu_relax(); /* For when BUG is null */
1047 EXPORT_SYMBOL_GPL(do_exit
);
1049 NORET_TYPE
void complete_and_exit(struct completion
*comp
, long code
)
1057 EXPORT_SYMBOL(complete_and_exit
);
1059 SYSCALL_DEFINE1(exit
, int, error_code
)
1061 do_exit((error_code
&0xff)<<8);
1065 * Take down every thread in the group. This is called by fatal signals
1066 * as well as by sys_exit_group (below).
1069 do_group_exit(int exit_code
)
1071 struct signal_struct
*sig
= current
->signal
;
1073 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
1075 if (signal_group_exit(sig
))
1076 exit_code
= sig
->group_exit_code
;
1077 else if (!thread_group_empty(current
)) {
1078 struct sighand_struct
*const sighand
= current
->sighand
;
1079 spin_lock_irq(&sighand
->siglock
);
1080 if (signal_group_exit(sig
))
1081 /* Another thread got here before we took the lock. */
1082 exit_code
= sig
->group_exit_code
;
1084 sig
->group_exit_code
= exit_code
;
1085 sig
->flags
= SIGNAL_GROUP_EXIT
;
1086 zap_other_threads(current
);
1088 spin_unlock_irq(&sighand
->siglock
);
1096 * this kills every thread in the thread group. Note that any externally
1097 * wait4()-ing process will get the correct exit code - even if this
1098 * thread is not the thread group leader.
1100 SYSCALL_DEFINE1(exit_group
, int, error_code
)
1102 do_group_exit((error_code
& 0xff) << 8);
1107 static struct pid
*task_pid_type(struct task_struct
*task
, enum pid_type type
)
1109 struct pid
*pid
= NULL
;
1110 if (type
== PIDTYPE_PID
)
1111 pid
= task
->pids
[type
].pid
;
1112 else if (type
< PIDTYPE_MAX
)
1113 pid
= task
->group_leader
->pids
[type
].pid
;
1117 static int eligible_child(enum pid_type type
, struct pid
*pid
, int options
,
1118 struct task_struct
*p
)
1122 if (type
< PIDTYPE_MAX
) {
1123 if (task_pid_type(p
, type
) != pid
)
1127 /* Wait for all children (clone and not) if __WALL is set;
1128 * otherwise, wait for clone children *only* if __WCLONE is
1129 * set; otherwise, wait for non-clone children *only*. (Note:
1130 * A "clone" child here is one that reports to its parent
1131 * using a signal other than SIGCHLD.) */
1132 if (((p
->exit_signal
!= SIGCHLD
) ^ ((options
& __WCLONE
) != 0))
1133 && !(options
& __WALL
))
1136 err
= security_task_wait(p
);
1143 static int wait_noreap_copyout(struct task_struct
*p
, pid_t pid
, uid_t uid
,
1144 int why
, int status
,
1145 struct siginfo __user
*infop
,
1146 struct rusage __user
*rusagep
)
1148 int retval
= rusagep
? getrusage(p
, RUSAGE_BOTH
, rusagep
) : 0;
1152 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1154 retval
= put_user(0, &infop
->si_errno
);
1156 retval
= put_user((short)why
, &infop
->si_code
);
1158 retval
= put_user(pid
, &infop
->si_pid
);
1160 retval
= put_user(uid
, &infop
->si_uid
);
1162 retval
= put_user(status
, &infop
->si_status
);
1169 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1170 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1171 * the lock and this task is uninteresting. If we return nonzero, we have
1172 * released the lock and the system call should return.
1174 static int wait_task_zombie(struct task_struct
*p
, int options
,
1175 struct siginfo __user
*infop
,
1176 int __user
*stat_addr
, struct rusage __user
*ru
)
1178 unsigned long state
;
1179 int retval
, status
, traced
;
1180 pid_t pid
= task_pid_vnr(p
);
1181 uid_t uid
= __task_cred(p
)->uid
;
1183 if (!likely(options
& WEXITED
))
1186 if (unlikely(options
& WNOWAIT
)) {
1187 int exit_code
= p
->exit_code
;
1191 read_unlock(&tasklist_lock
);
1192 if ((exit_code
& 0x7f) == 0) {
1194 status
= exit_code
>> 8;
1196 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1197 status
= exit_code
& 0x7f;
1199 return wait_noreap_copyout(p
, pid
, uid
, why
,
1204 * Try to move the task's state to DEAD
1205 * only one thread is allowed to do this:
1207 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1208 if (state
!= EXIT_ZOMBIE
) {
1209 BUG_ON(state
!= EXIT_DEAD
);
1213 traced
= ptrace_reparented(p
);
1215 if (likely(!traced
)) {
1216 struct signal_struct
*psig
;
1217 struct signal_struct
*sig
;
1218 struct task_cputime cputime
;
1221 * The resource counters for the group leader are in its
1222 * own task_struct. Those for dead threads in the group
1223 * are in its signal_struct, as are those for the child
1224 * processes it has previously reaped. All these
1225 * accumulate in the parent's signal_struct c* fields.
1227 * We don't bother to take a lock here to protect these
1228 * p->signal fields, because they are only touched by
1229 * __exit_signal, which runs with tasklist_lock
1230 * write-locked anyway, and so is excluded here. We do
1231 * need to protect the access to p->parent->signal fields,
1232 * as other threads in the parent group can be right
1233 * here reaping other children at the same time.
1235 * We use thread_group_cputime() to get times for the thread
1236 * group, which consolidates times for all threads in the
1237 * group including the group leader.
1239 thread_group_cputime(p
, &cputime
);
1240 spin_lock_irq(&p
->parent
->sighand
->siglock
);
1241 psig
= p
->parent
->signal
;
1244 cputime_add(psig
->cutime
,
1245 cputime_add(cputime
.utime
,
1248 cputime_add(psig
->cstime
,
1249 cputime_add(cputime
.stime
,
1252 cputime_add(psig
->cgtime
,
1253 cputime_add(p
->gtime
,
1254 cputime_add(sig
->gtime
,
1257 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1259 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1261 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1263 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1265 task_io_get_inblock(p
) +
1266 sig
->inblock
+ sig
->cinblock
;
1268 task_io_get_oublock(p
) +
1269 sig
->oublock
+ sig
->coublock
;
1270 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1271 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1272 spin_unlock_irq(&p
->parent
->sighand
->siglock
);
1276 * Now we are sure this task is interesting, and no other
1277 * thread can reap it because we set its state to EXIT_DEAD.
1279 read_unlock(&tasklist_lock
);
1281 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1282 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1283 ? p
->signal
->group_exit_code
: p
->exit_code
;
1284 if (!retval
&& stat_addr
)
1285 retval
= put_user(status
, stat_addr
);
1286 if (!retval
&& infop
)
1287 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1288 if (!retval
&& infop
)
1289 retval
= put_user(0, &infop
->si_errno
);
1290 if (!retval
&& infop
) {
1293 if ((status
& 0x7f) == 0) {
1297 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1300 retval
= put_user((short)why
, &infop
->si_code
);
1302 retval
= put_user(status
, &infop
->si_status
);
1304 if (!retval
&& infop
)
1305 retval
= put_user(pid
, &infop
->si_pid
);
1306 if (!retval
&& infop
)
1307 retval
= put_user(uid
, &infop
->si_uid
);
1312 write_lock_irq(&tasklist_lock
);
1313 /* We dropped tasklist, ptracer could die and untrace */
1316 * If this is not a detached task, notify the parent.
1317 * If it's still not detached after that, don't release
1320 if (!task_detached(p
)) {
1321 do_notify_parent(p
, p
->exit_signal
);
1322 if (!task_detached(p
)) {
1323 p
->exit_state
= EXIT_ZOMBIE
;
1327 write_unlock_irq(&tasklist_lock
);
1335 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1338 if (task_is_stopped_or_traced(p
))
1339 return &p
->exit_code
;
1341 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1342 return &p
->signal
->group_exit_code
;
1348 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1349 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1350 * the lock and this task is uninteresting. If we return nonzero, we have
1351 * released the lock and the system call should return.
1353 static int wait_task_stopped(int ptrace
, struct task_struct
*p
,
1354 int options
, struct siginfo __user
*infop
,
1355 int __user
*stat_addr
, struct rusage __user
*ru
)
1357 int retval
, exit_code
, *p_code
, why
;
1358 uid_t uid
= 0; /* unneeded, required by compiler */
1361 if (!(options
& WUNTRACED
))
1365 spin_lock_irq(&p
->sighand
->siglock
);
1367 p_code
= task_stopped_code(p
, ptrace
);
1368 if (unlikely(!p_code
))
1371 exit_code
= *p_code
;
1375 if (!unlikely(options
& WNOWAIT
))
1378 /* don't need the RCU readlock here as we're holding a spinlock */
1379 uid
= __task_cred(p
)->uid
;
1381 spin_unlock_irq(&p
->sighand
->siglock
);
1386 * Now we are pretty sure this task is interesting.
1387 * Make sure it doesn't get reaped out from under us while we
1388 * give up the lock and then examine it below. We don't want to
1389 * keep holding onto the tasklist_lock while we call getrusage and
1390 * possibly take page faults for user memory.
1393 pid
= task_pid_vnr(p
);
1394 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1395 read_unlock(&tasklist_lock
);
1397 if (unlikely(options
& WNOWAIT
))
1398 return wait_noreap_copyout(p
, pid
, uid
,
1402 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1403 if (!retval
&& stat_addr
)
1404 retval
= put_user((exit_code
<< 8) | 0x7f, stat_addr
);
1405 if (!retval
&& infop
)
1406 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1407 if (!retval
&& infop
)
1408 retval
= put_user(0, &infop
->si_errno
);
1409 if (!retval
&& infop
)
1410 retval
= put_user((short)why
, &infop
->si_code
);
1411 if (!retval
&& infop
)
1412 retval
= put_user(exit_code
, &infop
->si_status
);
1413 if (!retval
&& infop
)
1414 retval
= put_user(pid
, &infop
->si_pid
);
1415 if (!retval
&& infop
)
1416 retval
= put_user(uid
, &infop
->si_uid
);
1426 * Handle do_wait work for one task in a live, non-stopped state.
1427 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1428 * the lock and this task is uninteresting. If we return nonzero, we have
1429 * released the lock and the system call should return.
1431 static int wait_task_continued(struct task_struct
*p
, int options
,
1432 struct siginfo __user
*infop
,
1433 int __user
*stat_addr
, struct rusage __user
*ru
)
1439 if (!unlikely(options
& WCONTINUED
))
1442 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1445 spin_lock_irq(&p
->sighand
->siglock
);
1446 /* Re-check with the lock held. */
1447 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1448 spin_unlock_irq(&p
->sighand
->siglock
);
1451 if (!unlikely(options
& WNOWAIT
))
1452 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1453 uid
= __task_cred(p
)->uid
;
1454 spin_unlock_irq(&p
->sighand
->siglock
);
1456 pid
= task_pid_vnr(p
);
1458 read_unlock(&tasklist_lock
);
1461 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1463 if (!retval
&& stat_addr
)
1464 retval
= put_user(0xffff, stat_addr
);
1468 retval
= wait_noreap_copyout(p
, pid
, uid
,
1469 CLD_CONTINUED
, SIGCONT
,
1471 BUG_ON(retval
== 0);
1478 * Consider @p for a wait by @parent.
1480 * -ECHILD should be in *@notask_error before the first call.
1481 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1482 * Returns zero if the search for a child should continue;
1483 * then *@notask_error is 0 if @p is an eligible child,
1484 * or another error from security_task_wait(), or still -ECHILD.
1486 static int wait_consider_task(struct task_struct
*parent
, int ptrace
,
1487 struct task_struct
*p
, int *notask_error
,
1488 enum pid_type type
, struct pid
*pid
, int options
,
1489 struct siginfo __user
*infop
,
1490 int __user
*stat_addr
, struct rusage __user
*ru
)
1492 int ret
= eligible_child(type
, pid
, options
, p
);
1496 if (unlikely(ret
< 0)) {
1498 * If we have not yet seen any eligible child,
1499 * then let this error code replace -ECHILD.
1500 * A permission error will give the user a clue
1501 * to look for security policy problems, rather
1502 * than for mysterious wait bugs.
1505 *notask_error
= ret
;
1508 if (likely(!ptrace
) && unlikely(p
->ptrace
)) {
1510 * This child is hidden by ptrace.
1511 * We aren't allowed to see it now, but eventually we will.
1517 if (p
->exit_state
== EXIT_DEAD
)
1521 * We don't reap group leaders with subthreads.
1523 if (p
->exit_state
== EXIT_ZOMBIE
&& !delay_group_leader(p
))
1524 return wait_task_zombie(p
, options
, infop
, stat_addr
, ru
);
1527 * It's stopped or running now, so it might
1528 * later continue, exit, or stop again.
1532 if (task_stopped_code(p
, ptrace
))
1533 return wait_task_stopped(ptrace
, p
, options
,
1534 infop
, stat_addr
, ru
);
1536 return wait_task_continued(p
, options
, infop
, stat_addr
, ru
);
1540 * Do the work of do_wait() for one thread in the group, @tsk.
1542 * -ECHILD should be in *@notask_error before the first call.
1543 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1544 * Returns zero if the search for a child should continue; then
1545 * *@notask_error is 0 if there were any eligible children,
1546 * or another error from security_task_wait(), or still -ECHILD.
1548 static int do_wait_thread(struct task_struct
*tsk
, int *notask_error
,
1549 enum pid_type type
, struct pid
*pid
, int options
,
1550 struct siginfo __user
*infop
, int __user
*stat_addr
,
1551 struct rusage __user
*ru
)
1553 struct task_struct
*p
;
1555 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1557 * Do not consider detached threads.
1559 if (!task_detached(p
)) {
1560 int ret
= wait_consider_task(tsk
, 0, p
, notask_error
,
1562 infop
, stat_addr
, ru
);
1571 static int ptrace_do_wait(struct task_struct
*tsk
, int *notask_error
,
1572 enum pid_type type
, struct pid
*pid
, int options
,
1573 struct siginfo __user
*infop
, int __user
*stat_addr
,
1574 struct rusage __user
*ru
)
1576 struct task_struct
*p
;
1579 * Traditionally we see ptrace'd stopped tasks regardless of options.
1581 options
|= WUNTRACED
;
1583 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1584 int ret
= wait_consider_task(tsk
, 1, p
, notask_error
,
1586 infop
, stat_addr
, ru
);
1594 static long do_wait(enum pid_type type
, struct pid
*pid
, int options
,
1595 struct siginfo __user
*infop
, int __user
*stat_addr
,
1596 struct rusage __user
*ru
)
1598 DECLARE_WAITQUEUE(wait
, current
);
1599 struct task_struct
*tsk
;
1602 trace_sched_process_wait(pid
);
1604 add_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1607 * If there is nothing that can match our critiera just get out.
1608 * We will clear @retval to zero if we see any child that might later
1609 * match our criteria, even if we are not able to reap it yet.
1612 if ((type
< PIDTYPE_MAX
) && (!pid
|| hlist_empty(&pid
->tasks
[type
])))
1615 current
->state
= TASK_INTERRUPTIBLE
;
1616 read_lock(&tasklist_lock
);
1619 int tsk_result
= do_wait_thread(tsk
, &retval
,
1621 infop
, stat_addr
, ru
);
1623 tsk_result
= ptrace_do_wait(tsk
, &retval
,
1625 infop
, stat_addr
, ru
);
1628 * tasklist_lock is unlocked and we have a final result.
1630 retval
= tsk_result
;
1634 if (options
& __WNOTHREAD
)
1636 tsk
= next_thread(tsk
);
1637 BUG_ON(tsk
->signal
!= current
->signal
);
1638 } while (tsk
!= current
);
1639 read_unlock(&tasklist_lock
);
1641 if (!retval
&& !(options
& WNOHANG
)) {
1642 retval
= -ERESTARTSYS
;
1643 if (!signal_pending(current
)) {
1650 current
->state
= TASK_RUNNING
;
1651 remove_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1657 * For a WNOHANG return, clear out all the fields
1658 * we would set so the user can easily tell the
1662 retval
= put_user(0, &infop
->si_signo
);
1664 retval
= put_user(0, &infop
->si_errno
);
1666 retval
= put_user(0, &infop
->si_code
);
1668 retval
= put_user(0, &infop
->si_pid
);
1670 retval
= put_user(0, &infop
->si_uid
);
1672 retval
= put_user(0, &infop
->si_status
);
1678 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1679 infop
, int, options
, struct rusage __user
*, ru
)
1681 struct pid
*pid
= NULL
;
1685 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1687 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1700 type
= PIDTYPE_PGID
;
1708 if (type
< PIDTYPE_MAX
)
1709 pid
= find_get_pid(upid
);
1710 ret
= do_wait(type
, pid
, options
, infop
, NULL
, ru
);
1713 /* avoid REGPARM breakage on x86: */
1714 asmlinkage_protect(5, ret
, which
, upid
, infop
, options
, ru
);
1718 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1719 int, options
, struct rusage __user
*, ru
)
1721 struct pid
*pid
= NULL
;
1725 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1726 __WNOTHREAD
|__WCLONE
|__WALL
))
1731 else if (upid
< 0) {
1732 type
= PIDTYPE_PGID
;
1733 pid
= find_get_pid(-upid
);
1734 } else if (upid
== 0) {
1735 type
= PIDTYPE_PGID
;
1736 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1737 } else /* upid > 0 */ {
1739 pid
= find_get_pid(upid
);
1742 ret
= do_wait(type
, pid
, options
| WEXITED
, NULL
, stat_addr
, ru
);
1745 /* avoid REGPARM breakage on x86: */
1746 asmlinkage_protect(4, ret
, upid
, stat_addr
, options
, ru
);
1750 #ifdef __ARCH_WANT_SYS_WAITPID
1753 * sys_waitpid() remains for compatibility. waitpid() should be
1754 * implemented by calling sys_wait4() from libc.a.
1756 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1758 return sys_wait4(pid
, stat_addr
, options
, NULL
);
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