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/fs_struct.h>
50 #include <linux/init_task.h>
51 #include <trace/sched.h>
53 #include <asm/uaccess.h>
54 #include <asm/unistd.h>
55 #include <asm/pgtable.h>
56 #include <asm/mmu_context.h>
57 #include "cred-internals.h"
59 DEFINE_TRACE(sched_process_free
);
60 DEFINE_TRACE(sched_process_exit
);
61 DEFINE_TRACE(sched_process_wait
);
63 static void exit_mm(struct task_struct
* tsk
);
65 static void __unhash_process(struct task_struct
*p
)
68 detach_pid(p
, PIDTYPE_PID
);
69 if (thread_group_leader(p
)) {
70 detach_pid(p
, PIDTYPE_PGID
);
71 detach_pid(p
, PIDTYPE_SID
);
73 list_del_rcu(&p
->tasks
);
74 __get_cpu_var(process_counts
)--;
76 list_del_rcu(&p
->thread_group
);
77 list_del_init(&p
->sibling
);
81 * This function expects the tasklist_lock write-locked.
83 static void __exit_signal(struct task_struct
*tsk
)
85 struct signal_struct
*sig
= tsk
->signal
;
86 struct sighand_struct
*sighand
;
89 BUG_ON(!atomic_read(&sig
->count
));
91 sighand
= rcu_dereference(tsk
->sighand
);
92 spin_lock(&sighand
->siglock
);
94 posix_cpu_timers_exit(tsk
);
95 if (atomic_dec_and_test(&sig
->count
))
96 posix_cpu_timers_exit_group(tsk
);
99 * If there is any task waiting for the group exit
102 if (sig
->group_exit_task
&& atomic_read(&sig
->count
) == sig
->notify_count
)
103 wake_up_process(sig
->group_exit_task
);
105 if (tsk
== sig
->curr_target
)
106 sig
->curr_target
= next_thread(tsk
);
108 * Accumulate here the counters for all threads but the
109 * group leader as they die, so they can be added into
110 * the process-wide totals when those are taken.
111 * The group leader stays around as a zombie as long
112 * as there are other threads. When it gets reaped,
113 * the exit.c code will add its counts into these totals.
114 * We won't ever get here for the group leader, since it
115 * will have been the last reference on the signal_struct.
117 sig
->utime
= cputime_add(sig
->utime
, task_utime(tsk
));
118 sig
->stime
= cputime_add(sig
->stime
, task_stime(tsk
));
119 sig
->gtime
= cputime_add(sig
->gtime
, task_gtime(tsk
));
120 sig
->min_flt
+= tsk
->min_flt
;
121 sig
->maj_flt
+= tsk
->maj_flt
;
122 sig
->nvcsw
+= tsk
->nvcsw
;
123 sig
->nivcsw
+= tsk
->nivcsw
;
124 sig
->inblock
+= task_io_get_inblock(tsk
);
125 sig
->oublock
+= task_io_get_oublock(tsk
);
126 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
127 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
128 sig
= NULL
; /* Marker for below. */
131 __unhash_process(tsk
);
134 * Do this under ->siglock, we can race with another thread
135 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
137 flush_sigqueue(&tsk
->pending
);
141 spin_unlock(&sighand
->siglock
);
143 __cleanup_sighand(sighand
);
144 clear_tsk_thread_flag(tsk
,TIF_SIGPENDING
);
146 flush_sigqueue(&sig
->shared_pending
);
147 taskstats_tgid_free(sig
);
149 * Make sure ->signal can't go away under rq->lock,
150 * see account_group_exec_runtime().
152 task_rq_unlock_wait(tsk
);
153 __cleanup_signal(sig
);
157 static void delayed_put_task_struct(struct rcu_head
*rhp
)
159 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
161 #ifdef CONFIG_PERF_COUNTERS
162 WARN_ON_ONCE(!list_empty(&tsk
->perf_counter_ctx
.counter_list
));
164 trace_sched_process_free(tsk
);
165 put_task_struct(tsk
);
169 void release_task(struct task_struct
* p
)
171 struct task_struct
*leader
;
174 tracehook_prepare_release_task(p
);
175 /* don't need to get the RCU readlock here - the process is dead and
176 * can't be modifying its own credentials */
177 atomic_dec(&__task_cred(p
)->user
->processes
);
181 write_lock_irq(&tasklist_lock
);
182 tracehook_finish_release_task(p
);
186 * If we are the last non-leader member of the thread
187 * group, and the leader is zombie, then notify the
188 * group leader's parent process. (if it wants notification.)
191 leader
= p
->group_leader
;
192 if (leader
!= p
&& thread_group_empty(leader
) && leader
->exit_state
== EXIT_ZOMBIE
) {
193 BUG_ON(task_detached(leader
));
194 do_notify_parent(leader
, leader
->exit_signal
);
196 * If we were the last child thread and the leader has
197 * exited already, and the leader's parent ignores SIGCHLD,
198 * then we are the one who should release the leader.
200 * do_notify_parent() will have marked it self-reaping in
203 zap_leader
= task_detached(leader
);
206 * This maintains the invariant that release_task()
207 * only runs on a task in EXIT_DEAD, just for sanity.
210 leader
->exit_state
= EXIT_DEAD
;
213 write_unlock_irq(&tasklist_lock
);
215 call_rcu(&p
->rcu
, delayed_put_task_struct
);
218 if (unlikely(zap_leader
))
223 * This checks not only the pgrp, but falls back on the pid if no
224 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
227 * The caller must hold rcu lock or the tasklist lock.
229 struct pid
*session_of_pgrp(struct pid
*pgrp
)
231 struct task_struct
*p
;
232 struct pid
*sid
= NULL
;
234 p
= pid_task(pgrp
, PIDTYPE_PGID
);
236 p
= pid_task(pgrp
, PIDTYPE_PID
);
238 sid
= task_session(p
);
244 * Determine if a process group is "orphaned", according to the POSIX
245 * definition in 2.2.2.52. Orphaned process groups are not to be affected
246 * by terminal-generated stop signals. Newly orphaned process groups are
247 * to receive a SIGHUP and a SIGCONT.
249 * "I ask you, have you ever known what it is to be an orphan?"
251 static int will_become_orphaned_pgrp(struct pid
*pgrp
, struct task_struct
*ignored_task
)
253 struct task_struct
*p
;
255 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
256 if ((p
== ignored_task
) ||
257 (p
->exit_state
&& thread_group_empty(p
)) ||
258 is_global_init(p
->real_parent
))
261 if (task_pgrp(p
->real_parent
) != pgrp
&&
262 task_session(p
->real_parent
) == task_session(p
))
264 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
269 int is_current_pgrp_orphaned(void)
273 read_lock(&tasklist_lock
);
274 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
275 read_unlock(&tasklist_lock
);
280 static int has_stopped_jobs(struct pid
*pgrp
)
283 struct task_struct
*p
;
285 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
286 if (!task_is_stopped(p
))
290 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
295 * Check to see if any process groups have become orphaned as
296 * a result of our exiting, and if they have any stopped jobs,
297 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
300 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
302 struct pid
*pgrp
= task_pgrp(tsk
);
303 struct task_struct
*ignored_task
= tsk
;
306 /* exit: our father is in a different pgrp than
307 * we are and we were the only connection outside.
309 parent
= tsk
->real_parent
;
311 /* reparent: our child is in a different pgrp than
312 * we are, and it was the only connection outside.
316 if (task_pgrp(parent
) != pgrp
&&
317 task_session(parent
) == task_session(tsk
) &&
318 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
319 has_stopped_jobs(pgrp
)) {
320 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
321 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
326 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
328 * If a kernel thread is launched as a result of a system call, or if
329 * it ever exits, it should generally reparent itself to kthreadd so it
330 * isn't in the way of other processes and is correctly cleaned up on exit.
332 * The various task state such as scheduling policy and priority may have
333 * been inherited from a user process, so we reset them to sane values here.
335 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
337 static void reparent_to_kthreadd(void)
339 write_lock_irq(&tasklist_lock
);
341 ptrace_unlink(current
);
342 /* Reparent to init */
343 current
->real_parent
= current
->parent
= kthreadd_task
;
344 list_move_tail(¤t
->sibling
, ¤t
->real_parent
->children
);
346 /* Set the exit signal to SIGCHLD so we signal init on exit */
347 current
->exit_signal
= SIGCHLD
;
349 if (task_nice(current
) < 0)
350 set_user_nice(current
, 0);
354 memcpy(current
->signal
->rlim
, init_task
.signal
->rlim
,
355 sizeof(current
->signal
->rlim
));
357 atomic_inc(&init_cred
.usage
);
358 commit_creds(&init_cred
);
359 write_unlock_irq(&tasklist_lock
);
362 void __set_special_pids(struct pid
*pid
)
364 struct task_struct
*curr
= current
->group_leader
;
366 if (task_session(curr
) != pid
)
367 change_pid(curr
, PIDTYPE_SID
, pid
);
369 if (task_pgrp(curr
) != pid
)
370 change_pid(curr
, PIDTYPE_PGID
, pid
);
373 static void set_special_pids(struct pid
*pid
)
375 write_lock_irq(&tasklist_lock
);
376 __set_special_pids(pid
);
377 write_unlock_irq(&tasklist_lock
);
381 * Let kernel threads use this to say that they
382 * allow a certain signal (since daemonize() will
383 * have disabled all of them by default).
385 int allow_signal(int sig
)
387 if (!valid_signal(sig
) || sig
< 1)
390 spin_lock_irq(¤t
->sighand
->siglock
);
391 sigdelset(¤t
->blocked
, sig
);
393 /* Kernel threads handle their own signals.
394 Let the signal code know it'll be handled, so
395 that they don't get converted to SIGKILL or
396 just silently dropped */
397 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= (void __user
*)2;
400 spin_unlock_irq(¤t
->sighand
->siglock
);
404 EXPORT_SYMBOL(allow_signal
);
406 int disallow_signal(int sig
)
408 if (!valid_signal(sig
) || sig
< 1)
411 spin_lock_irq(¤t
->sighand
->siglock
);
412 current
->sighand
->action
[(sig
)-1].sa
.sa_handler
= SIG_IGN
;
414 spin_unlock_irq(¤t
->sighand
->siglock
);
418 EXPORT_SYMBOL(disallow_signal
);
421 * Put all the gunge required to become a kernel thread without
422 * attached user resources in one place where it belongs.
425 void daemonize(const char *name
, ...)
430 va_start(args
, name
);
431 vsnprintf(current
->comm
, sizeof(current
->comm
), name
, args
);
435 * If we were started as result of loading a module, close all of the
436 * user space pages. We don't need them, and if we didn't close them
437 * they would be locked into memory.
441 * We don't want to have TIF_FREEZE set if the system-wide hibernation
442 * or suspend transition begins right now.
444 current
->flags
|= (PF_NOFREEZE
| PF_KTHREAD
);
446 if (current
->nsproxy
!= &init_nsproxy
) {
447 get_nsproxy(&init_nsproxy
);
448 switch_task_namespaces(current
, &init_nsproxy
);
450 set_special_pids(&init_struct_pid
);
451 proc_clear_tty(current
);
453 /* Block and flush all signals */
454 sigfillset(&blocked
);
455 sigprocmask(SIG_BLOCK
, &blocked
, NULL
);
456 flush_signals(current
);
458 /* Become as one with the init task */
460 daemonize_fs_struct();
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 #ifdef CONFIG_MM_OWNER
561 * Task p is exiting and it owned mm, lets find a new owner for it
564 mm_need_new_owner(struct mm_struct
*mm
, struct task_struct
*p
)
567 * If there are other users of the mm and the owner (us) is exiting
568 * we need to find a new owner to take on the responsibility.
570 if (atomic_read(&mm
->mm_users
) <= 1)
577 void mm_update_next_owner(struct mm_struct
*mm
)
579 struct task_struct
*c
, *g
, *p
= current
;
582 if (!mm_need_new_owner(mm
, p
))
585 read_lock(&tasklist_lock
);
587 * Search in the children
589 list_for_each_entry(c
, &p
->children
, sibling
) {
591 goto assign_new_owner
;
595 * Search in the siblings
597 list_for_each_entry(c
, &p
->parent
->children
, sibling
) {
599 goto assign_new_owner
;
603 * Search through everything else. We should not get
606 do_each_thread(g
, c
) {
608 goto assign_new_owner
;
609 } while_each_thread(g
, c
);
611 read_unlock(&tasklist_lock
);
613 * We found no owner yet mm_users > 1: this implies that we are
614 * most likely racing with swapoff (try_to_unuse()) or /proc or
615 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
624 * The task_lock protects c->mm from changing.
625 * We always want mm->owner->mm == mm
629 * Delay read_unlock() till we have the task_lock()
630 * to ensure that c does not slip away underneath us
632 read_unlock(&tasklist_lock
);
642 #endif /* CONFIG_MM_OWNER */
645 * Turn us into a lazy TLB process if we
648 static void exit_mm(struct task_struct
* tsk
)
650 struct mm_struct
*mm
= tsk
->mm
;
651 struct core_state
*core_state
;
657 * Serialize with any possible pending coredump.
658 * We must hold mmap_sem around checking core_state
659 * and clearing tsk->mm. The core-inducing thread
660 * will increment ->nr_threads for each thread in the
661 * group with ->mm != NULL.
663 down_read(&mm
->mmap_sem
);
664 core_state
= mm
->core_state
;
666 struct core_thread self
;
667 up_read(&mm
->mmap_sem
);
670 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
672 * Implies mb(), the result of xchg() must be visible
673 * to core_state->dumper.
675 if (atomic_dec_and_test(&core_state
->nr_threads
))
676 complete(&core_state
->startup
);
679 set_task_state(tsk
, TASK_UNINTERRUPTIBLE
);
680 if (!self
.task
) /* see coredump_finish() */
684 __set_task_state(tsk
, TASK_RUNNING
);
685 down_read(&mm
->mmap_sem
);
687 atomic_inc(&mm
->mm_count
);
688 BUG_ON(mm
!= tsk
->active_mm
);
689 /* more a memory barrier than a real lock */
692 up_read(&mm
->mmap_sem
);
693 enter_lazy_tlb(mm
, current
);
694 /* We don't want this task to be frozen prematurely */
695 clear_freeze_flag(tsk
);
697 mm_update_next_owner(mm
);
702 * When we die, we re-parent all our children.
703 * Try to give them to another thread in our thread
704 * group, and if no such member exists, give it to
705 * the child reaper process (ie "init") in our pid
708 static struct task_struct
*find_new_reaper(struct task_struct
*father
)
710 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
711 struct task_struct
*thread
;
714 while_each_thread(father
, thread
) {
715 if (thread
->flags
& PF_EXITING
)
717 if (unlikely(pid_ns
->child_reaper
== father
))
718 pid_ns
->child_reaper
= thread
;
722 if (unlikely(pid_ns
->child_reaper
== father
)) {
723 write_unlock_irq(&tasklist_lock
);
724 if (unlikely(pid_ns
== &init_pid_ns
))
725 panic("Attempted to kill init!");
727 zap_pid_ns_processes(pid_ns
);
728 write_lock_irq(&tasklist_lock
);
730 * We can not clear ->child_reaper or leave it alone.
731 * There may by stealth EXIT_DEAD tasks on ->children,
732 * forget_original_parent() must move them somewhere.
734 pid_ns
->child_reaper
= init_pid_ns
.child_reaper
;
737 return pid_ns
->child_reaper
;
741 * Any that need to be release_task'd are put on the @dead list.
743 static void reparent_thread(struct task_struct
*father
, struct task_struct
*p
,
744 struct list_head
*dead
)
746 if (p
->pdeath_signal
)
747 group_send_sig_info(p
->pdeath_signal
, SEND_SIG_NOINFO
, p
);
749 list_move_tail(&p
->sibling
, &p
->real_parent
->children
);
751 if (task_detached(p
))
754 * If this is a threaded reparent there is no need to
755 * notify anyone anything has happened.
757 if (same_thread_group(p
->real_parent
, father
))
760 /* We don't want people slaying init. */
761 p
->exit_signal
= SIGCHLD
;
763 /* If it has exited notify the new parent about this child's death. */
765 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
766 do_notify_parent(p
, p
->exit_signal
);
767 if (task_detached(p
)) {
768 p
->exit_state
= EXIT_DEAD
;
769 list_move_tail(&p
->sibling
, dead
);
773 kill_orphaned_pgrp(p
, father
);
776 static void forget_original_parent(struct task_struct
*father
)
778 struct task_struct
*p
, *n
, *reaper
;
779 LIST_HEAD(dead_children
);
783 write_lock_irq(&tasklist_lock
);
784 reaper
= find_new_reaper(father
);
786 list_for_each_entry_safe(p
, n
, &father
->children
, sibling
) {
787 p
->real_parent
= reaper
;
788 if (p
->parent
== father
) {
790 p
->parent
= p
->real_parent
;
792 reparent_thread(father
, p
, &dead_children
);
794 write_unlock_irq(&tasklist_lock
);
796 BUG_ON(!list_empty(&father
->children
));
798 list_for_each_entry_safe(p
, n
, &dead_children
, sibling
) {
799 list_del_init(&p
->sibling
);
805 * Send signals to all our closest relatives so that they know
806 * to properly mourn us..
808 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
814 * This does two things:
816 * A. Make init inherit all the child processes
817 * B. Check to see if any process groups have become orphaned
818 * as a result of our exiting, and if they have any stopped
819 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
821 forget_original_parent(tsk
);
822 exit_task_namespaces(tsk
);
824 write_lock_irq(&tasklist_lock
);
826 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
828 /* Let father know we died
830 * Thread signals are configurable, but you aren't going to use
831 * that to send signals to arbitary processes.
832 * That stops right now.
834 * If the parent exec id doesn't match the exec id we saved
835 * when we started then we know the parent has changed security
838 * If our self_exec id doesn't match our parent_exec_id then
839 * we have changed execution domain as these two values started
840 * the same after a fork.
842 if (tsk
->exit_signal
!= SIGCHLD
&& !task_detached(tsk
) &&
843 (tsk
->parent_exec_id
!= tsk
->real_parent
->self_exec_id
||
844 tsk
->self_exec_id
!= tsk
->parent_exec_id
))
845 tsk
->exit_signal
= SIGCHLD
;
847 signal
= tracehook_notify_death(tsk
, &cookie
, group_dead
);
849 signal
= do_notify_parent(tsk
, signal
);
851 tsk
->exit_state
= signal
== DEATH_REAP
? EXIT_DEAD
: EXIT_ZOMBIE
;
853 /* mt-exec, de_thread() is waiting for us */
854 if (thread_group_leader(tsk
) &&
855 tsk
->signal
->group_exit_task
&&
856 tsk
->signal
->notify_count
< 0)
857 wake_up_process(tsk
->signal
->group_exit_task
);
859 write_unlock_irq(&tasklist_lock
);
861 tracehook_report_death(tsk
, signal
, cookie
, group_dead
);
863 /* If the process is dead, release it - nobody will wait for it */
864 if (signal
== DEATH_REAP
)
868 #ifdef CONFIG_DEBUG_STACK_USAGE
869 static void check_stack_usage(void)
871 static DEFINE_SPINLOCK(low_water_lock
);
872 static int lowest_to_date
= THREAD_SIZE
;
875 free
= stack_not_used(current
);
877 if (free
>= lowest_to_date
)
880 spin_lock(&low_water_lock
);
881 if (free
< lowest_to_date
) {
882 printk(KERN_WARNING
"%s used greatest stack depth: %lu bytes "
884 current
->comm
, free
);
885 lowest_to_date
= free
;
887 spin_unlock(&low_water_lock
);
890 static inline void check_stack_usage(void) {}
893 NORET_TYPE
void do_exit(long code
)
895 struct task_struct
*tsk
= current
;
898 profile_task_exit(tsk
);
900 WARN_ON(atomic_read(&tsk
->fs_excl
));
902 if (unlikely(in_interrupt()))
903 panic("Aiee, killing interrupt handler!");
904 if (unlikely(!tsk
->pid
))
905 panic("Attempted to kill the idle task!");
907 tracehook_report_exit(&code
);
910 * We're taking recursive faults here in do_exit. Safest is to just
911 * leave this task alone and wait for reboot.
913 if (unlikely(tsk
->flags
& PF_EXITING
)) {
915 "Fixing recursive fault but reboot is needed!\n");
917 * We can do this unlocked here. The futex code uses
918 * this flag just to verify whether the pi state
919 * cleanup has been done or not. In the worst case it
920 * loops once more. We pretend that the cleanup was
921 * done as there is no way to return. Either the
922 * OWNER_DIED bit is set by now or we push the blocked
923 * task into the wait for ever nirwana as well.
925 tsk
->flags
|= PF_EXITPIDONE
;
926 set_current_state(TASK_UNINTERRUPTIBLE
);
932 exit_signals(tsk
); /* sets PF_EXITING */
934 * tsk->flags are checked in the futex code to protect against
935 * an exiting task cleaning up the robust pi futexes.
938 spin_unlock_wait(&tsk
->pi_lock
);
940 if (unlikely(in_atomic()))
941 printk(KERN_INFO
"note: %s[%d] exited with preempt_count %d\n",
942 current
->comm
, task_pid_nr(current
),
945 acct_update_integrals(tsk
);
947 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
949 hrtimer_cancel(&tsk
->signal
->real_timer
);
950 exit_itimers(tsk
->signal
);
952 acct_collect(code
, group_dead
);
955 if (unlikely(tsk
->audit_context
))
958 tsk
->exit_code
= code
;
959 taskstats_exit(tsk
, group_dead
);
965 trace_sched_process_exit(tsk
);
974 if (group_dead
&& tsk
->signal
->leader
)
975 disassociate_ctty(1);
977 module_put(task_thread_info(tsk
)->exec_domain
->module
);
979 module_put(tsk
->binfmt
->module
);
981 proc_exit_connector(tsk
);
984 * Flush inherited counters to the parent - before the parent
985 * gets woken up by child-exit notifications.
987 perf_counter_exit_task(tsk
);
989 exit_notify(tsk
, group_dead
);
991 mpol_put(tsk
->mempolicy
);
992 tsk
->mempolicy
= NULL
;
995 if (unlikely(!list_empty(&tsk
->pi_state_list
)))
996 exit_pi_state_list(tsk
);
997 if (unlikely(current
->pi_state_cache
))
998 kfree(current
->pi_state_cache
);
1001 * Make sure we are holding no locks:
1003 debug_check_no_locks_held(tsk
);
1005 * We can do this unlocked here. The futex code uses this flag
1006 * just to verify whether the pi state cleanup has been done
1007 * or not. In the worst case it loops once more.
1009 tsk
->flags
|= PF_EXITPIDONE
;
1011 if (tsk
->io_context
)
1014 if (tsk
->splice_pipe
)
1015 __free_pipe_info(tsk
->splice_pipe
);
1018 /* causes final put_task_struct in finish_task_switch(). */
1019 tsk
->state
= TASK_DEAD
;
1022 /* Avoid "noreturn function does return". */
1024 cpu_relax(); /* For when BUG is null */
1027 EXPORT_SYMBOL_GPL(do_exit
);
1029 NORET_TYPE
void complete_and_exit(struct completion
*comp
, long code
)
1037 EXPORT_SYMBOL(complete_and_exit
);
1039 SYSCALL_DEFINE1(exit
, int, error_code
)
1041 do_exit((error_code
&0xff)<<8);
1045 * Take down every thread in the group. This is called by fatal signals
1046 * as well as by sys_exit_group (below).
1049 do_group_exit(int exit_code
)
1051 struct signal_struct
*sig
= current
->signal
;
1053 BUG_ON(exit_code
& 0x80); /* core dumps don't get here */
1055 if (signal_group_exit(sig
))
1056 exit_code
= sig
->group_exit_code
;
1057 else if (!thread_group_empty(current
)) {
1058 struct sighand_struct
*const sighand
= current
->sighand
;
1059 spin_lock_irq(&sighand
->siglock
);
1060 if (signal_group_exit(sig
))
1061 /* Another thread got here before we took the lock. */
1062 exit_code
= sig
->group_exit_code
;
1064 sig
->group_exit_code
= exit_code
;
1065 sig
->flags
= SIGNAL_GROUP_EXIT
;
1066 zap_other_threads(current
);
1068 spin_unlock_irq(&sighand
->siglock
);
1076 * this kills every thread in the thread group. Note that any externally
1077 * wait4()-ing process will get the correct exit code - even if this
1078 * thread is not the thread group leader.
1080 SYSCALL_DEFINE1(exit_group
, int, error_code
)
1082 do_group_exit((error_code
& 0xff) << 8);
1087 static struct pid
*task_pid_type(struct task_struct
*task
, enum pid_type type
)
1089 struct pid
*pid
= NULL
;
1090 if (type
== PIDTYPE_PID
)
1091 pid
= task
->pids
[type
].pid
;
1092 else if (type
< PIDTYPE_MAX
)
1093 pid
= task
->group_leader
->pids
[type
].pid
;
1097 static int eligible_child(enum pid_type type
, struct pid
*pid
, int options
,
1098 struct task_struct
*p
)
1102 if (type
< PIDTYPE_MAX
) {
1103 if (task_pid_type(p
, type
) != pid
)
1107 /* Wait for all children (clone and not) if __WALL is set;
1108 * otherwise, wait for clone children *only* if __WCLONE is
1109 * set; otherwise, wait for non-clone children *only*. (Note:
1110 * A "clone" child here is one that reports to its parent
1111 * using a signal other than SIGCHLD.) */
1112 if (((p
->exit_signal
!= SIGCHLD
) ^ ((options
& __WCLONE
) != 0))
1113 && !(options
& __WALL
))
1116 err
= security_task_wait(p
);
1123 static int wait_noreap_copyout(struct task_struct
*p
, pid_t pid
, uid_t uid
,
1124 int why
, int status
,
1125 struct siginfo __user
*infop
,
1126 struct rusage __user
*rusagep
)
1128 int retval
= rusagep
? getrusage(p
, RUSAGE_BOTH
, rusagep
) : 0;
1132 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1134 retval
= put_user(0, &infop
->si_errno
);
1136 retval
= put_user((short)why
, &infop
->si_code
);
1138 retval
= put_user(pid
, &infop
->si_pid
);
1140 retval
= put_user(uid
, &infop
->si_uid
);
1142 retval
= put_user(status
, &infop
->si_status
);
1149 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1150 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1151 * the lock and this task is uninteresting. If we return nonzero, we have
1152 * released the lock and the system call should return.
1154 static int wait_task_zombie(struct task_struct
*p
, int options
,
1155 struct siginfo __user
*infop
,
1156 int __user
*stat_addr
, struct rusage __user
*ru
)
1158 unsigned long state
;
1159 int retval
, status
, traced
;
1160 pid_t pid
= task_pid_vnr(p
);
1161 uid_t uid
= __task_cred(p
)->uid
;
1163 if (!likely(options
& WEXITED
))
1166 if (unlikely(options
& WNOWAIT
)) {
1167 int exit_code
= p
->exit_code
;
1171 read_unlock(&tasklist_lock
);
1172 if ((exit_code
& 0x7f) == 0) {
1174 status
= exit_code
>> 8;
1176 why
= (exit_code
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1177 status
= exit_code
& 0x7f;
1179 return wait_noreap_copyout(p
, pid
, uid
, why
,
1184 * Try to move the task's state to DEAD
1185 * only one thread is allowed to do this:
1187 state
= xchg(&p
->exit_state
, EXIT_DEAD
);
1188 if (state
!= EXIT_ZOMBIE
) {
1189 BUG_ON(state
!= EXIT_DEAD
);
1193 traced
= ptrace_reparented(p
);
1195 if (likely(!traced
)) {
1196 struct signal_struct
*psig
;
1197 struct signal_struct
*sig
;
1198 struct task_cputime cputime
;
1201 * The resource counters for the group leader are in its
1202 * own task_struct. Those for dead threads in the group
1203 * are in its signal_struct, as are those for the child
1204 * processes it has previously reaped. All these
1205 * accumulate in the parent's signal_struct c* fields.
1207 * We don't bother to take a lock here to protect these
1208 * p->signal fields, because they are only touched by
1209 * __exit_signal, which runs with tasklist_lock
1210 * write-locked anyway, and so is excluded here. We do
1211 * need to protect the access to p->parent->signal fields,
1212 * as other threads in the parent group can be right
1213 * here reaping other children at the same time.
1215 * We use thread_group_cputime() to get times for the thread
1216 * group, which consolidates times for all threads in the
1217 * group including the group leader.
1219 thread_group_cputime(p
, &cputime
);
1220 spin_lock_irq(&p
->parent
->sighand
->siglock
);
1221 psig
= p
->parent
->signal
;
1224 cputime_add(psig
->cutime
,
1225 cputime_add(cputime
.utime
,
1228 cputime_add(psig
->cstime
,
1229 cputime_add(cputime
.stime
,
1232 cputime_add(psig
->cgtime
,
1233 cputime_add(p
->gtime
,
1234 cputime_add(sig
->gtime
,
1237 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1239 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1241 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1243 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1245 task_io_get_inblock(p
) +
1246 sig
->inblock
+ sig
->cinblock
;
1248 task_io_get_oublock(p
) +
1249 sig
->oublock
+ sig
->coublock
;
1250 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1251 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1252 spin_unlock_irq(&p
->parent
->sighand
->siglock
);
1256 * Now we are sure this task is interesting, and no other
1257 * thread can reap it because we set its state to EXIT_DEAD.
1259 read_unlock(&tasklist_lock
);
1261 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1262 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1263 ? p
->signal
->group_exit_code
: p
->exit_code
;
1264 if (!retval
&& stat_addr
)
1265 retval
= put_user(status
, stat_addr
);
1266 if (!retval
&& infop
)
1267 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1268 if (!retval
&& infop
)
1269 retval
= put_user(0, &infop
->si_errno
);
1270 if (!retval
&& infop
) {
1273 if ((status
& 0x7f) == 0) {
1277 why
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1280 retval
= put_user((short)why
, &infop
->si_code
);
1282 retval
= put_user(status
, &infop
->si_status
);
1284 if (!retval
&& infop
)
1285 retval
= put_user(pid
, &infop
->si_pid
);
1286 if (!retval
&& infop
)
1287 retval
= put_user(uid
, &infop
->si_uid
);
1292 write_lock_irq(&tasklist_lock
);
1293 /* We dropped tasklist, ptracer could die and untrace */
1296 * If this is not a detached task, notify the parent.
1297 * If it's still not detached after that, don't release
1300 if (!task_detached(p
)) {
1301 do_notify_parent(p
, p
->exit_signal
);
1302 if (!task_detached(p
)) {
1303 p
->exit_state
= EXIT_ZOMBIE
;
1307 write_unlock_irq(&tasklist_lock
);
1315 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1318 if (task_is_stopped_or_traced(p
))
1319 return &p
->exit_code
;
1321 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1322 return &p
->signal
->group_exit_code
;
1328 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1329 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1330 * the lock and this task is uninteresting. If we return nonzero, we have
1331 * released the lock and the system call should return.
1333 static int wait_task_stopped(int ptrace
, struct task_struct
*p
,
1334 int options
, struct siginfo __user
*infop
,
1335 int __user
*stat_addr
, struct rusage __user
*ru
)
1337 int retval
, exit_code
, *p_code
, why
;
1338 uid_t uid
= 0; /* unneeded, required by compiler */
1341 if (!(options
& WUNTRACED
))
1345 spin_lock_irq(&p
->sighand
->siglock
);
1347 p_code
= task_stopped_code(p
, ptrace
);
1348 if (unlikely(!p_code
))
1351 exit_code
= *p_code
;
1355 if (!unlikely(options
& WNOWAIT
))
1358 /* don't need the RCU readlock here as we're holding a spinlock */
1359 uid
= __task_cred(p
)->uid
;
1361 spin_unlock_irq(&p
->sighand
->siglock
);
1366 * Now we are pretty sure this task is interesting.
1367 * Make sure it doesn't get reaped out from under us while we
1368 * give up the lock and then examine it below. We don't want to
1369 * keep holding onto the tasklist_lock while we call getrusage and
1370 * possibly take page faults for user memory.
1373 pid
= task_pid_vnr(p
);
1374 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1375 read_unlock(&tasklist_lock
);
1377 if (unlikely(options
& WNOWAIT
))
1378 return wait_noreap_copyout(p
, pid
, uid
,
1382 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1383 if (!retval
&& stat_addr
)
1384 retval
= put_user((exit_code
<< 8) | 0x7f, stat_addr
);
1385 if (!retval
&& infop
)
1386 retval
= put_user(SIGCHLD
, &infop
->si_signo
);
1387 if (!retval
&& infop
)
1388 retval
= put_user(0, &infop
->si_errno
);
1389 if (!retval
&& infop
)
1390 retval
= put_user((short)why
, &infop
->si_code
);
1391 if (!retval
&& infop
)
1392 retval
= put_user(exit_code
, &infop
->si_status
);
1393 if (!retval
&& infop
)
1394 retval
= put_user(pid
, &infop
->si_pid
);
1395 if (!retval
&& infop
)
1396 retval
= put_user(uid
, &infop
->si_uid
);
1406 * Handle do_wait work for one task in a live, non-stopped state.
1407 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1408 * the lock and this task is uninteresting. If we return nonzero, we have
1409 * released the lock and the system call should return.
1411 static int wait_task_continued(struct task_struct
*p
, int options
,
1412 struct siginfo __user
*infop
,
1413 int __user
*stat_addr
, struct rusage __user
*ru
)
1419 if (!unlikely(options
& WCONTINUED
))
1422 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1425 spin_lock_irq(&p
->sighand
->siglock
);
1426 /* Re-check with the lock held. */
1427 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1428 spin_unlock_irq(&p
->sighand
->siglock
);
1431 if (!unlikely(options
& WNOWAIT
))
1432 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1433 uid
= __task_cred(p
)->uid
;
1434 spin_unlock_irq(&p
->sighand
->siglock
);
1436 pid
= task_pid_vnr(p
);
1438 read_unlock(&tasklist_lock
);
1441 retval
= ru
? getrusage(p
, RUSAGE_BOTH
, ru
) : 0;
1443 if (!retval
&& stat_addr
)
1444 retval
= put_user(0xffff, stat_addr
);
1448 retval
= wait_noreap_copyout(p
, pid
, uid
,
1449 CLD_CONTINUED
, SIGCONT
,
1451 BUG_ON(retval
== 0);
1458 * Consider @p for a wait by @parent.
1460 * -ECHILD should be in *@notask_error before the first call.
1461 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1462 * Returns zero if the search for a child should continue;
1463 * then *@notask_error is 0 if @p is an eligible child,
1464 * or another error from security_task_wait(), or still -ECHILD.
1466 static int wait_consider_task(struct task_struct
*parent
, int ptrace
,
1467 struct task_struct
*p
, int *notask_error
,
1468 enum pid_type type
, struct pid
*pid
, int options
,
1469 struct siginfo __user
*infop
,
1470 int __user
*stat_addr
, struct rusage __user
*ru
)
1472 int ret
= eligible_child(type
, pid
, options
, p
);
1476 if (unlikely(ret
< 0)) {
1478 * If we have not yet seen any eligible child,
1479 * then let this error code replace -ECHILD.
1480 * A permission error will give the user a clue
1481 * to look for security policy problems, rather
1482 * than for mysterious wait bugs.
1485 *notask_error
= ret
;
1488 if (likely(!ptrace
) && unlikely(p
->ptrace
)) {
1490 * This child is hidden by ptrace.
1491 * We aren't allowed to see it now, but eventually we will.
1497 if (p
->exit_state
== EXIT_DEAD
)
1501 * We don't reap group leaders with subthreads.
1503 if (p
->exit_state
== EXIT_ZOMBIE
&& !delay_group_leader(p
))
1504 return wait_task_zombie(p
, options
, infop
, stat_addr
, ru
);
1507 * It's stopped or running now, so it might
1508 * later continue, exit, or stop again.
1512 if (task_stopped_code(p
, ptrace
))
1513 return wait_task_stopped(ptrace
, p
, options
,
1514 infop
, stat_addr
, ru
);
1516 return wait_task_continued(p
, options
, infop
, stat_addr
, ru
);
1520 * Do the work of do_wait() for one thread in the group, @tsk.
1522 * -ECHILD should be in *@notask_error before the first call.
1523 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1524 * Returns zero if the search for a child should continue; then
1525 * *@notask_error is 0 if there were any eligible children,
1526 * or another error from security_task_wait(), or still -ECHILD.
1528 static int do_wait_thread(struct task_struct
*tsk
, int *notask_error
,
1529 enum pid_type type
, struct pid
*pid
, int options
,
1530 struct siginfo __user
*infop
, int __user
*stat_addr
,
1531 struct rusage __user
*ru
)
1533 struct task_struct
*p
;
1535 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1537 * Do not consider detached threads.
1539 if (!task_detached(p
)) {
1540 int ret
= wait_consider_task(tsk
, 0, p
, notask_error
,
1542 infop
, stat_addr
, ru
);
1551 static int ptrace_do_wait(struct task_struct
*tsk
, int *notask_error
,
1552 enum pid_type type
, struct pid
*pid
, int options
,
1553 struct siginfo __user
*infop
, int __user
*stat_addr
,
1554 struct rusage __user
*ru
)
1556 struct task_struct
*p
;
1559 * Traditionally we see ptrace'd stopped tasks regardless of options.
1561 options
|= WUNTRACED
;
1563 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1564 int ret
= wait_consider_task(tsk
, 1, p
, notask_error
,
1566 infop
, stat_addr
, ru
);
1574 static long do_wait(enum pid_type type
, struct pid
*pid
, int options
,
1575 struct siginfo __user
*infop
, int __user
*stat_addr
,
1576 struct rusage __user
*ru
)
1578 DECLARE_WAITQUEUE(wait
, current
);
1579 struct task_struct
*tsk
;
1582 trace_sched_process_wait(pid
);
1584 add_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1587 * If there is nothing that can match our critiera just get out.
1588 * We will clear @retval to zero if we see any child that might later
1589 * match our criteria, even if we are not able to reap it yet.
1592 if ((type
< PIDTYPE_MAX
) && (!pid
|| hlist_empty(&pid
->tasks
[type
])))
1595 current
->state
= TASK_INTERRUPTIBLE
;
1596 read_lock(&tasklist_lock
);
1599 int tsk_result
= do_wait_thread(tsk
, &retval
,
1601 infop
, stat_addr
, ru
);
1603 tsk_result
= ptrace_do_wait(tsk
, &retval
,
1605 infop
, stat_addr
, ru
);
1608 * tasklist_lock is unlocked and we have a final result.
1610 retval
= tsk_result
;
1614 if (options
& __WNOTHREAD
)
1616 tsk
= next_thread(tsk
);
1617 BUG_ON(tsk
->signal
!= current
->signal
);
1618 } while (tsk
!= current
);
1619 read_unlock(&tasklist_lock
);
1621 if (!retval
&& !(options
& WNOHANG
)) {
1622 retval
= -ERESTARTSYS
;
1623 if (!signal_pending(current
)) {
1630 current
->state
= TASK_RUNNING
;
1631 remove_wait_queue(¤t
->signal
->wait_chldexit
,&wait
);
1637 * For a WNOHANG return, clear out all the fields
1638 * we would set so the user can easily tell the
1642 retval
= put_user(0, &infop
->si_signo
);
1644 retval
= put_user(0, &infop
->si_errno
);
1646 retval
= put_user(0, &infop
->si_code
);
1648 retval
= put_user(0, &infop
->si_pid
);
1650 retval
= put_user(0, &infop
->si_uid
);
1652 retval
= put_user(0, &infop
->si_status
);
1658 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1659 infop
, int, options
, struct rusage __user
*, ru
)
1661 struct pid
*pid
= NULL
;
1665 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
))
1667 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1680 type
= PIDTYPE_PGID
;
1688 if (type
< PIDTYPE_MAX
)
1689 pid
= find_get_pid(upid
);
1690 ret
= do_wait(type
, pid
, options
, infop
, NULL
, ru
);
1693 /* avoid REGPARM breakage on x86: */
1694 asmlinkage_protect(5, ret
, which
, upid
, infop
, options
, ru
);
1698 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1699 int, options
, struct rusage __user
*, ru
)
1701 struct pid
*pid
= NULL
;
1705 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1706 __WNOTHREAD
|__WCLONE
|__WALL
))
1711 else if (upid
< 0) {
1712 type
= PIDTYPE_PGID
;
1713 pid
= find_get_pid(-upid
);
1714 } else if (upid
== 0) {
1715 type
= PIDTYPE_PGID
;
1716 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1717 } else /* upid > 0 */ {
1719 pid
= find_get_pid(upid
);
1722 ret
= do_wait(type
, pid
, options
| WEXITED
, NULL
, stat_addr
, ru
);
1725 /* avoid REGPARM breakage on x86: */
1726 asmlinkage_protect(4, ret
, upid
, stat_addr
, options
, ru
);
1730 #ifdef __ARCH_WANT_SYS_WAITPID
1733 * sys_waitpid() remains for compatibility. waitpid() should be
1734 * implemented by calling sys_wait4() from libc.a.
1736 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1738 return sys_wait4(pid
, stat_addr
, options
, NULL
);