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/key.h>
17 #include <linux/security.h>
18 #include <linux/cpu.h>
19 #include <linux/acct.h>
20 #include <linux/tsacct_kern.h>
21 #include <linux/file.h>
22 #include <linux/binfmts.h>
23 #include <linux/nsproxy.h>
24 #include <linux/pid_namespace.h>
25 #include <linux/ptrace.h>
26 #include <linux/profile.h>
27 #include <linux/mount.h>
28 #include <linux/proc_fs.h>
29 #include <linux/kthread.h>
30 #include <linux/mempolicy.h>
31 #include <linux/taskstats_kern.h>
32 #include <linux/delayacct.h>
33 #include <linux/freezer.h>
34 #include <linux/cgroup.h>
35 #include <linux/syscalls.h>
36 #include <linux/signal.h>
37 #include <linux/posix-timers.h>
38 #include <linux/cn_proc.h>
39 #include <linux/mutex.h>
40 #include <linux/futex.h>
41 #include <linux/compat.h>
42 #include <linux/pipe_fs_i.h>
43 #include <linux/audit.h> /* for audit_free() */
44 #include <linux/resource.h>
45 #include <linux/blkdev.h>
46 #include <linux/task_io_accounting_ops.h>
48 #include <asm/uaccess.h>
49 #include <asm/unistd.h>
50 #include <asm/pgtable.h>
51 #include <asm/mmu_context.h>
53 static void exit_mm(struct task_struct * tsk);
55 static inline int task_detached(struct task_struct *p)
57 return p->exit_signal == -1;
60 static void __unhash_process(struct task_struct *p)
63 detach_pid(p, PIDTYPE_PID);
64 if (thread_group_leader(p)) {
65 detach_pid(p, PIDTYPE_PGID);
66 detach_pid(p, PIDTYPE_SID);
68 list_del_rcu(&p->tasks);
69 __get_cpu_var(process_counts)--;
71 list_del_rcu(&p->thread_group);
76 * This function expects the tasklist_lock write-locked.
78 static void __exit_signal(struct task_struct *tsk)
80 struct signal_struct *sig = tsk->signal;
81 struct sighand_struct *sighand;
84 BUG_ON(!atomic_read(&sig->count));
87 sighand = rcu_dereference(tsk->sighand);
88 spin_lock(&sighand->siglock);
90 posix_cpu_timers_exit(tsk);
91 if (atomic_dec_and_test(&sig->count))
92 posix_cpu_timers_exit_group(tsk);
95 * If there is any task waiting for the group exit
98 if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count)
99 wake_up_process(sig->group_exit_task);
101 if (tsk == sig->curr_target)
102 sig->curr_target = next_thread(tsk);
104 * Accumulate here the counters for all threads but the
105 * group leader as they die, so they can be added into
106 * the process-wide totals when those are taken.
107 * The group leader stays around as a zombie as long
108 * as there are other threads. When it gets reaped,
109 * the exit.c code will add its counts into these totals.
110 * We won't ever get here for the group leader, since it
111 * will have been the last reference on the signal_struct.
113 sig->utime = cputime_add(sig->utime, tsk->utime);
114 sig->stime = cputime_add(sig->stime, tsk->stime);
115 sig->gtime = cputime_add(sig->gtime, tsk->gtime);
116 sig->min_flt += tsk->min_flt;
117 sig->maj_flt += tsk->maj_flt;
118 sig->nvcsw += tsk->nvcsw;
119 sig->nivcsw += tsk->nivcsw;
120 sig->inblock += task_io_get_inblock(tsk);
121 sig->oublock += task_io_get_oublock(tsk);
122 sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
123 sig = NULL; /* Marker for below. */
126 __unhash_process(tsk);
130 spin_unlock(&sighand->siglock);
133 __cleanup_sighand(sighand);
134 clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
135 flush_sigqueue(&tsk->pending);
137 flush_sigqueue(&sig->shared_pending);
138 taskstats_tgid_free(sig);
139 __cleanup_signal(sig);
143 static void delayed_put_task_struct(struct rcu_head *rhp)
145 put_task_struct(container_of(rhp, struct task_struct, rcu));
148 void release_task(struct task_struct * p)
150 struct task_struct *leader;
153 atomic_dec(&p->user->processes);
155 write_lock_irq(&tasklist_lock);
157 BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
161 * If we are the last non-leader member of the thread
162 * group, and the leader is zombie, then notify the
163 * group leader's parent process. (if it wants notification.)
166 leader = p->group_leader;
167 if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
168 BUG_ON(task_detached(leader));
169 do_notify_parent(leader, leader->exit_signal);
171 * If we were the last child thread and the leader has
172 * exited already, and the leader's parent ignores SIGCHLD,
173 * then we are the one who should release the leader.
175 * do_notify_parent() will have marked it self-reaping in
178 zap_leader = task_detached(leader);
181 write_unlock_irq(&tasklist_lock);
183 call_rcu(&p->rcu, delayed_put_task_struct);
186 if (unlikely(zap_leader))
191 * This checks not only the pgrp, but falls back on the pid if no
192 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
195 * The caller must hold rcu lock or the tasklist lock.
197 struct pid *session_of_pgrp(struct pid *pgrp)
199 struct task_struct *p;
200 struct pid *sid = NULL;
202 p = pid_task(pgrp, PIDTYPE_PGID);
204 p = pid_task(pgrp, PIDTYPE_PID);
206 sid = task_session(p);
212 * Determine if a process group is "orphaned", according to the POSIX
213 * definition in 2.2.2.52. Orphaned process groups are not to be affected
214 * by terminal-generated stop signals. Newly orphaned process groups are
215 * to receive a SIGHUP and a SIGCONT.
217 * "I ask you, have you ever known what it is to be an orphan?"
219 static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task)
221 struct task_struct *p;
223 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
224 if ((p == ignored_task) ||
225 (p->exit_state && thread_group_empty(p)) ||
226 is_global_init(p->real_parent))
229 if (task_pgrp(p->real_parent) != pgrp &&
230 task_session(p->real_parent) == task_session(p))
232 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
237 int is_current_pgrp_orphaned(void)
241 read_lock(&tasklist_lock);
242 retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
243 read_unlock(&tasklist_lock);
248 static int has_stopped_jobs(struct pid *pgrp)
251 struct task_struct *p;
253 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
254 if (!task_is_stopped(p))
258 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
263 * Check to see if any process groups have become orphaned as
264 * a result of our exiting, and if they have any stopped jobs,
265 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
268 kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
270 struct pid *pgrp = task_pgrp(tsk);
271 struct task_struct *ignored_task = tsk;
274 /* exit: our father is in a different pgrp than
275 * we are and we were the only connection outside.
277 parent = tsk->real_parent;
279 /* reparent: our child is in a different pgrp than
280 * we are, and it was the only connection outside.
284 if (task_pgrp(parent) != pgrp &&
285 task_session(parent) == task_session(tsk) &&
286 will_become_orphaned_pgrp(pgrp, ignored_task) &&
287 has_stopped_jobs(pgrp)) {
288 __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
289 __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
294 * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd
296 * If a kernel thread is launched as a result of a system call, or if
297 * it ever exits, it should generally reparent itself to kthreadd so it
298 * isn't in the way of other processes and is correctly cleaned up on exit.
300 * The various task state such as scheduling policy and priority may have
301 * been inherited from a user process, so we reset them to sane values here.
303 * NOTE that reparent_to_kthreadd() gives the caller full capabilities.
305 static void reparent_to_kthreadd(void)
307 write_lock_irq(&tasklist_lock);
309 ptrace_unlink(current);
310 /* Reparent to init */
311 remove_parent(current);
312 current->real_parent = current->parent = kthreadd_task;
315 /* Set the exit signal to SIGCHLD so we signal init on exit */
316 current->exit_signal = SIGCHLD;
318 if (task_nice(current) < 0)
319 set_user_nice(current, 0);
323 security_task_reparent_to_init(current);
324 memcpy(current->signal->rlim, init_task.signal->rlim,
325 sizeof(current->signal->rlim));
326 atomic_inc(&(INIT_USER->__count));
327 write_unlock_irq(&tasklist_lock);
328 switch_uid(INIT_USER);
331 void __set_special_pids(struct pid *pid)
333 struct task_struct *curr = current->group_leader;
334 pid_t nr = pid_nr(pid);
336 if (task_session(curr) != pid) {
337 detach_pid(curr, PIDTYPE_SID);
338 attach_pid(curr, PIDTYPE_SID, pid);
339 set_task_session(curr, nr);
341 if (task_pgrp(curr) != pid) {
342 detach_pid(curr, PIDTYPE_PGID);
343 attach_pid(curr, PIDTYPE_PGID, pid);
344 set_task_pgrp(curr, nr);
348 static void set_special_pids(struct pid *pid)
350 write_lock_irq(&tasklist_lock);
351 __set_special_pids(pid);
352 write_unlock_irq(&tasklist_lock);
356 * Let kernel threads use this to say that they
357 * allow a certain signal (since daemonize() will
358 * have disabled all of them by default).
360 int allow_signal(int sig)
362 if (!valid_signal(sig) || sig < 1)
365 spin_lock_irq(¤t->sighand->siglock);
366 sigdelset(¤t->blocked, sig);
368 /* Kernel threads handle their own signals.
369 Let the signal code know it'll be handled, so
370 that they don't get converted to SIGKILL or
371 just silently dropped */
372 current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
375 spin_unlock_irq(¤t->sighand->siglock);
379 EXPORT_SYMBOL(allow_signal);
381 int disallow_signal(int sig)
383 if (!valid_signal(sig) || sig < 1)
386 spin_lock_irq(¤t->sighand->siglock);
387 current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN;
389 spin_unlock_irq(¤t->sighand->siglock);
393 EXPORT_SYMBOL(disallow_signal);
396 * Put all the gunge required to become a kernel thread without
397 * attached user resources in one place where it belongs.
400 void daemonize(const char *name, ...)
403 struct fs_struct *fs;
406 va_start(args, name);
407 vsnprintf(current->comm, sizeof(current->comm), name, args);
411 * If we were started as result of loading a module, close all of the
412 * user space pages. We don't need them, and if we didn't close them
413 * they would be locked into memory.
417 * We don't want to have TIF_FREEZE set if the system-wide hibernation
418 * or suspend transition begins right now.
420 current->flags |= PF_NOFREEZE;
422 if (current->nsproxy != &init_nsproxy) {
423 get_nsproxy(&init_nsproxy);
424 switch_task_namespaces(current, &init_nsproxy);
426 set_special_pids(&init_struct_pid);
427 proc_clear_tty(current);
429 /* Block and flush all signals */
430 sigfillset(&blocked);
431 sigprocmask(SIG_BLOCK, &blocked, NULL);
432 flush_signals(current);
434 /* Become as one with the init task */
436 exit_fs(current); /* current->fs->count--; */
439 atomic_inc(&fs->count);
442 current->files = init_task.files;
443 atomic_inc(¤t->files->count);
445 reparent_to_kthreadd();
448 EXPORT_SYMBOL(daemonize);
450 static void close_files(struct files_struct * files)
458 * It is safe to dereference the fd table without RCU or
459 * ->file_lock because this is the last reference to the
462 fdt = files_fdtable(files);
466 if (i >= fdt->max_fds)
468 set = fdt->open_fds->fds_bits[j++];
471 struct file * file = xchg(&fdt->fd[i], NULL);
473 filp_close(file, files);
483 struct files_struct *get_files_struct(struct task_struct *task)
485 struct files_struct *files;
490 atomic_inc(&files->count);
496 void put_files_struct(struct files_struct *files)
500 if (atomic_dec_and_test(&files->count)) {
503 * Free the fd and fdset arrays if we expanded them.
504 * If the fdtable was embedded, pass files for freeing
505 * at the end of the RCU grace period. Otherwise,
506 * you can free files immediately.
508 fdt = files_fdtable(files);
509 if (fdt != &files->fdtab)
510 kmem_cache_free(files_cachep, files);
515 void reset_files_struct(struct files_struct *files)
517 struct task_struct *tsk = current;
518 struct files_struct *old;
524 put_files_struct(old);
527 void exit_files(struct task_struct *tsk)
529 struct files_struct * files = tsk->files;
535 put_files_struct(files);
539 void put_fs_struct(struct fs_struct *fs)
541 /* No need to hold fs->lock if we are killing it */
542 if (atomic_dec_and_test(&fs->count)) {
545 if (fs->altroot.dentry)
546 path_put(&fs->altroot);
547 kmem_cache_free(fs_cachep, fs);
551 void exit_fs(struct task_struct *tsk)
553 struct fs_struct * fs = tsk->fs;
563 EXPORT_SYMBOL_GPL(exit_fs);
565 #ifdef CONFIG_MM_OWNER
567 * Task p is exiting and it owned mm, lets find a new owner for it
570 mm_need_new_owner(struct mm_struct *mm, struct task_struct *p)
573 * If there are other users of the mm and the owner (us) is exiting
574 * we need to find a new owner to take on the responsibility.
578 if (atomic_read(&mm->mm_users) <= 1)
585 void mm_update_next_owner(struct mm_struct *mm)
587 struct task_struct *c, *g, *p = current;
590 if (!mm_need_new_owner(mm, p))
593 read_lock(&tasklist_lock);
595 * Search in the children
597 list_for_each_entry(c, &p->children, sibling) {
599 goto assign_new_owner;
603 * Search in the siblings
605 list_for_each_entry(c, &p->parent->children, sibling) {
607 goto assign_new_owner;
611 * Search through everything else. We should not get
614 do_each_thread(g, c) {
616 goto assign_new_owner;
617 } while_each_thread(g, c);
619 read_unlock(&tasklist_lock);
626 * The task_lock protects c->mm from changing.
627 * We always want mm->owner->mm == mm
631 * Delay read_unlock() till we have the task_lock()
632 * to ensure that c does not slip away underneath us
634 read_unlock(&tasklist_lock);
640 cgroup_mm_owner_callbacks(mm->owner, c);
645 #endif /* CONFIG_MM_OWNER */
648 * Turn us into a lazy TLB process if we
651 static void exit_mm(struct task_struct * tsk)
653 struct mm_struct *mm = tsk->mm;
659 * Serialize with any possible pending coredump.
660 * We must hold mmap_sem around checking core_waiters
661 * and clearing tsk->mm. The core-inducing thread
662 * will increment core_waiters for each thread in the
663 * group with ->mm != NULL.
665 down_read(&mm->mmap_sem);
666 if (mm->core_waiters) {
667 up_read(&mm->mmap_sem);
668 down_write(&mm->mmap_sem);
669 if (!--mm->core_waiters)
670 complete(mm->core_startup_done);
671 up_write(&mm->mmap_sem);
673 wait_for_completion(&mm->core_done);
674 down_read(&mm->mmap_sem);
676 atomic_inc(&mm->mm_count);
677 BUG_ON(mm != tsk->active_mm);
678 /* more a memory barrier than a real lock */
681 up_read(&mm->mmap_sem);
682 enter_lazy_tlb(mm, current);
683 /* We don't want this task to be frozen prematurely */
684 clear_freeze_flag(tsk);
686 mm_update_next_owner(mm);
691 reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
693 if (p->pdeath_signal)
694 /* We already hold the tasklist_lock here. */
695 group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
697 /* Move the child from its dying parent to the new one. */
698 if (unlikely(traced)) {
699 /* Preserve ptrace links if someone else is tracing this child. */
700 list_del_init(&p->ptrace_list);
701 if (p->parent != p->real_parent)
702 list_add(&p->ptrace_list, &p->real_parent->ptrace_children);
704 /* If this child is being traced, then we're the one tracing it
705 * anyway, so let go of it.
709 p->parent = p->real_parent;
712 if (task_is_traced(p)) {
714 * If it was at a trace stop, turn it into
715 * a normal stop since it's no longer being
722 /* If this is a threaded reparent there is no need to
723 * notify anyone anything has happened.
725 if (same_thread_group(p->real_parent, father))
728 /* We don't want people slaying init. */
729 if (!task_detached(p))
730 p->exit_signal = SIGCHLD;
732 /* If we'd notified the old parent about this child's death,
733 * also notify the new parent.
735 if (!traced && p->exit_state == EXIT_ZOMBIE &&
736 !task_detached(p) && thread_group_empty(p))
737 do_notify_parent(p, p->exit_signal);
739 kill_orphaned_pgrp(p, father);
743 * When we die, we re-parent all our children.
744 * Try to give them to another thread in our thread
745 * group, and if no such member exists, give it to
746 * the child reaper process (ie "init") in our pid
749 static void forget_original_parent(struct task_struct *father)
751 struct task_struct *p, *n, *reaper = father;
752 struct list_head ptrace_dead;
754 INIT_LIST_HEAD(&ptrace_dead);
756 write_lock_irq(&tasklist_lock);
759 reaper = next_thread(reaper);
760 if (reaper == father) {
761 reaper = task_child_reaper(father);
764 } while (reaper->flags & PF_EXITING);
767 * There are only two places where our children can be:
769 * - in our child list
770 * - in our ptraced child list
772 * Search them and reparent children.
774 list_for_each_entry_safe(p, n, &father->children, sibling) {
779 /* if father isn't the real parent, then ptrace must be enabled */
780 BUG_ON(father != p->real_parent && !ptrace);
782 if (father == p->real_parent) {
783 /* reparent with a reaper, real father it's us */
784 p->real_parent = reaper;
785 reparent_thread(p, father, 0);
787 /* reparent ptraced task to its real parent */
789 if (p->exit_state == EXIT_ZOMBIE && !task_detached(p) &&
790 thread_group_empty(p))
791 do_notify_parent(p, p->exit_signal);
795 * if the ptraced child is a detached zombie we must collect
796 * it before we exit, or it will remain zombie forever since
797 * we prevented it from self-reap itself while it was being
798 * traced by us, to be able to see it in wait4.
800 if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && task_detached(p)))
801 list_add(&p->ptrace_list, &ptrace_dead);
804 list_for_each_entry_safe(p, n, &father->ptrace_children, ptrace_list) {
805 p->real_parent = reaper;
806 reparent_thread(p, father, 1);
809 write_unlock_irq(&tasklist_lock);
810 BUG_ON(!list_empty(&father->children));
811 BUG_ON(!list_empty(&father->ptrace_children));
813 list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_list) {
814 list_del_init(&p->ptrace_list);
821 * Send signals to all our closest relatives so that they know
822 * to properly mourn us..
824 static void exit_notify(struct task_struct *tsk, int group_dead)
829 * This does two things:
831 * A. Make init inherit all the child processes
832 * B. Check to see if any process groups have become orphaned
833 * as a result of our exiting, and if they have any stopped
834 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
836 forget_original_parent(tsk);
837 exit_task_namespaces(tsk);
839 write_lock_irq(&tasklist_lock);
841 kill_orphaned_pgrp(tsk->group_leader, NULL);
843 /* Let father know we died
845 * Thread signals are configurable, but you aren't going to use
846 * that to send signals to arbitary processes.
847 * That stops right now.
849 * If the parent exec id doesn't match the exec id we saved
850 * when we started then we know the parent has changed security
853 * If our self_exec id doesn't match our parent_exec_id then
854 * we have changed execution domain as these two values started
855 * the same after a fork.
857 if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) &&
858 (tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
859 tsk->self_exec_id != tsk->parent_exec_id) &&
861 tsk->exit_signal = SIGCHLD;
863 /* If something other than our normal parent is ptracing us, then
864 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
865 * only has special meaning to our real parent.
867 if (!task_detached(tsk) && thread_group_empty(tsk)) {
868 int signal = (tsk->parent == tsk->real_parent)
869 ? tsk->exit_signal : SIGCHLD;
870 do_notify_parent(tsk, signal);
871 } else if (tsk->ptrace) {
872 do_notify_parent(tsk, SIGCHLD);
876 if (task_detached(tsk) && likely(!tsk->ptrace))
878 tsk->exit_state = state;
880 /* mt-exec, de_thread() is waiting for us */
881 if (thread_group_leader(tsk) &&
882 tsk->signal->notify_count < 0 &&
883 tsk->signal->group_exit_task)
884 wake_up_process(tsk->signal->group_exit_task);
886 write_unlock_irq(&tasklist_lock);
888 /* If the process is dead, release it - nobody will wait for it */
889 if (state == EXIT_DEAD)
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;
898 unsigned long *n = end_of_stack(current);
903 free = (unsigned long)n - (unsigned long)end_of_stack(current);
905 if (free >= lowest_to_date)
908 spin_lock(&low_water_lock);
909 if (free < lowest_to_date) {
910 printk(KERN_WARNING "%s used greatest stack depth: %lu bytes "
912 current->comm, free);
913 lowest_to_date = free;
915 spin_unlock(&low_water_lock);
918 static inline void check_stack_usage(void) {}
921 static inline void exit_child_reaper(struct task_struct *tsk)
923 if (likely(tsk->group_leader != task_child_reaper(tsk)))
926 if (tsk->nsproxy->pid_ns == &init_pid_ns)
927 panic("Attempted to kill init!");
930 * @tsk is the last thread in the 'cgroup-init' and is exiting.
931 * Terminate all remaining processes in the namespace and reap them
932 * before exiting @tsk.
934 * Note that @tsk (last thread of cgroup-init) may not necessarily
935 * be the child-reaper (i.e main thread of cgroup-init) of the
936 * namespace i.e the child_reaper may have already exited.
938 * Even after a child_reaper exits, we let it inherit orphaned children,
939 * because, pid_ns->child_reaper remains valid as long as there is
940 * at least one living sub-thread in the cgroup init.
942 * This living sub-thread of the cgroup-init will be notified when
943 * a child inherited by the 'child-reaper' exits (do_notify_parent()
944 * uses __group_send_sig_info()). Further, when reaping child processes,
945 * do_wait() iterates over children of all living sub threads.
947 * i.e even though 'child_reaper' thread is listed as the parent of the
948 * orphaned children, any living sub-thread in the cgroup-init can
949 * perform the role of the child_reaper.
951 zap_pid_ns_processes(tsk->nsproxy->pid_ns);
954 NORET_TYPE void do_exit(long code)
956 struct task_struct *tsk = current;
959 profile_task_exit(tsk);
961 WARN_ON(atomic_read(&tsk->fs_excl));
963 if (unlikely(in_interrupt()))
964 panic("Aiee, killing interrupt handler!");
965 if (unlikely(!tsk->pid))
966 panic("Attempted to kill the idle task!");
968 if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
969 current->ptrace_message = code;
970 ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
974 * We're taking recursive faults here in do_exit. Safest is to just
975 * leave this task alone and wait for reboot.
977 if (unlikely(tsk->flags & PF_EXITING)) {
979 "Fixing recursive fault but reboot is needed!\n");
981 * We can do this unlocked here. The futex code uses
982 * this flag just to verify whether the pi state
983 * cleanup has been done or not. In the worst case it
984 * loops once more. We pretend that the cleanup was
985 * done as there is no way to return. Either the
986 * OWNER_DIED bit is set by now or we push the blocked
987 * task into the wait for ever nirwana as well.
989 tsk->flags |= PF_EXITPIDONE;
992 set_current_state(TASK_UNINTERRUPTIBLE);
996 exit_signals(tsk); /* sets PF_EXITING */
998 * tsk->flags are checked in the futex code to protect against
999 * an exiting task cleaning up the robust pi futexes.
1002 spin_unlock_wait(&tsk->pi_lock);
1004 if (unlikely(in_atomic()))
1005 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
1006 current->comm, task_pid_nr(current),
1009 acct_update_integrals(tsk);
1011 update_hiwater_rss(tsk->mm);
1012 update_hiwater_vm(tsk->mm);
1014 group_dead = atomic_dec_and_test(&tsk->signal->live);
1016 exit_child_reaper(tsk);
1017 hrtimer_cancel(&tsk->signal->real_timer);
1018 exit_itimers(tsk->signal);
1020 acct_collect(code, group_dead);
1022 if (unlikely(tsk->robust_list))
1023 exit_robust_list(tsk);
1024 #ifdef CONFIG_COMPAT
1025 if (unlikely(tsk->compat_robust_list))
1026 compat_exit_robust_list(tsk);
1031 if (unlikely(tsk->audit_context))
1034 tsk->exit_code = code;
1035 taskstats_exit(tsk, group_dead);
1044 check_stack_usage();
1046 cgroup_exit(tsk, 1);
1049 if (group_dead && tsk->signal->leader)
1050 disassociate_ctty(1);
1052 module_put(task_thread_info(tsk)->exec_domain->module);
1054 module_put(tsk->binfmt->module);
1056 proc_exit_connector(tsk);
1057 exit_notify(tsk, group_dead);
1059 mpol_put(tsk->mempolicy);
1060 tsk->mempolicy = NULL;
1064 * This must happen late, after the PID is not
1067 if (unlikely(!list_empty(&tsk->pi_state_list)))
1068 exit_pi_state_list(tsk);
1069 if (unlikely(current->pi_state_cache))
1070 kfree(current->pi_state_cache);
1073 * Make sure we are holding no locks:
1075 debug_check_no_locks_held(tsk);
1077 * We can do this unlocked here. The futex code uses this flag
1078 * just to verify whether the pi state cleanup has been done
1079 * or not. In the worst case it loops once more.
1081 tsk->flags |= PF_EXITPIDONE;
1083 if (tsk->io_context)
1086 if (tsk->splice_pipe)
1087 __free_pipe_info(tsk->splice_pipe);
1090 /* causes final put_task_struct in finish_task_switch(). */
1091 tsk->state = TASK_DEAD;
1095 /* Avoid "noreturn function does return". */
1097 cpu_relax(); /* For when BUG is null */
1100 EXPORT_SYMBOL_GPL(do_exit);
1102 NORET_TYPE void complete_and_exit(struct completion *comp, long code)
1110 EXPORT_SYMBOL(complete_and_exit);
1112 asmlinkage long sys_exit(int error_code)
1114 do_exit((error_code&0xff)<<8);
1118 * Take down every thread in the group. This is called by fatal signals
1119 * as well as by sys_exit_group (below).
1122 do_group_exit(int exit_code)
1124 struct signal_struct *sig = current->signal;
1126 BUG_ON(exit_code & 0x80); /* core dumps don't get here */
1128 if (signal_group_exit(sig))
1129 exit_code = sig->group_exit_code;
1130 else if (!thread_group_empty(current)) {
1131 struct sighand_struct *const sighand = current->sighand;
1132 spin_lock_irq(&sighand->siglock);
1133 if (signal_group_exit(sig))
1134 /* Another thread got here before we took the lock. */
1135 exit_code = sig->group_exit_code;
1137 sig->group_exit_code = exit_code;
1138 sig->flags = SIGNAL_GROUP_EXIT;
1139 zap_other_threads(current);
1141 spin_unlock_irq(&sighand->siglock);
1149 * this kills every thread in the thread group. Note that any externally
1150 * wait4()-ing process will get the correct exit code - even if this
1151 * thread is not the thread group leader.
1153 asmlinkage void sys_exit_group(int error_code)
1155 do_group_exit((error_code & 0xff) << 8);
1158 static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
1160 struct pid *pid = NULL;
1161 if (type == PIDTYPE_PID)
1162 pid = task->pids[type].pid;
1163 else if (type < PIDTYPE_MAX)
1164 pid = task->group_leader->pids[type].pid;
1168 static int eligible_child(enum pid_type type, struct pid *pid, int options,
1169 struct task_struct *p)
1173 if (type < PIDTYPE_MAX) {
1174 if (task_pid_type(p, type) != pid)
1179 * Do not consider detached threads that are
1182 if (task_detached(p) && !p->ptrace)
1185 /* Wait for all children (clone and not) if __WALL is set;
1186 * otherwise, wait for clone children *only* if __WCLONE is
1187 * set; otherwise, wait for non-clone children *only*. (Note:
1188 * A "clone" child here is one that reports to its parent
1189 * using a signal other than SIGCHLD.) */
1190 if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
1191 && !(options & __WALL))
1194 err = security_task_wait(p);
1198 if (type != PIDTYPE_PID)
1200 /* This child was explicitly requested, abort */
1201 read_unlock(&tasklist_lock);
1205 static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
1206 int why, int status,
1207 struct siginfo __user *infop,
1208 struct rusage __user *rusagep)
1210 int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
1214 retval = put_user(SIGCHLD, &infop->si_signo);
1216 retval = put_user(0, &infop->si_errno);
1218 retval = put_user((short)why, &infop->si_code);
1220 retval = put_user(pid, &infop->si_pid);
1222 retval = put_user(uid, &infop->si_uid);
1224 retval = put_user(status, &infop->si_status);
1231 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1232 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1233 * the lock and this task is uninteresting. If we return nonzero, we have
1234 * released the lock and the system call should return.
1236 static int wait_task_zombie(struct task_struct *p, int noreap,
1237 struct siginfo __user *infop,
1238 int __user *stat_addr, struct rusage __user *ru)
1240 unsigned long state;
1241 int retval, status, traced;
1242 pid_t pid = task_pid_vnr(p);
1244 if (unlikely(noreap)) {
1246 int exit_code = p->exit_code;
1250 read_unlock(&tasklist_lock);
1251 if ((exit_code & 0x7f) == 0) {
1253 status = exit_code >> 8;
1255 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
1256 status = exit_code & 0x7f;
1258 return wait_noreap_copyout(p, pid, uid, why,
1263 * Try to move the task's state to DEAD
1264 * only one thread is allowed to do this:
1266 state = xchg(&p->exit_state, EXIT_DEAD);
1267 if (state != EXIT_ZOMBIE) {
1268 BUG_ON(state != EXIT_DEAD);
1272 /* traced means p->ptrace, but not vice versa */
1273 traced = (p->real_parent != p->parent);
1275 if (likely(!traced)) {
1276 struct signal_struct *psig;
1277 struct signal_struct *sig;
1280 * The resource counters for the group leader are in its
1281 * own task_struct. Those for dead threads in the group
1282 * are in its signal_struct, as are those for the child
1283 * processes it has previously reaped. All these
1284 * accumulate in the parent's signal_struct c* fields.
1286 * We don't bother to take a lock here to protect these
1287 * p->signal fields, because they are only touched by
1288 * __exit_signal, which runs with tasklist_lock
1289 * write-locked anyway, and so is excluded here. We do
1290 * need to protect the access to p->parent->signal fields,
1291 * as other threads in the parent group can be right
1292 * here reaping other children at the same time.
1294 spin_lock_irq(&p->parent->sighand->siglock);
1295 psig = p->parent->signal;
1298 cputime_add(psig->cutime,
1299 cputime_add(p->utime,
1300 cputime_add(sig->utime,
1303 cputime_add(psig->cstime,
1304 cputime_add(p->stime,
1305 cputime_add(sig->stime,
1308 cputime_add(psig->cgtime,
1309 cputime_add(p->gtime,
1310 cputime_add(sig->gtime,
1313 p->min_flt + sig->min_flt + sig->cmin_flt;
1315 p->maj_flt + sig->maj_flt + sig->cmaj_flt;
1317 p->nvcsw + sig->nvcsw + sig->cnvcsw;
1319 p->nivcsw + sig->nivcsw + sig->cnivcsw;
1321 task_io_get_inblock(p) +
1322 sig->inblock + sig->cinblock;
1324 task_io_get_oublock(p) +
1325 sig->oublock + sig->coublock;
1326 spin_unlock_irq(&p->parent->sighand->siglock);
1330 * Now we are sure this task is interesting, and no other
1331 * thread can reap it because we set its state to EXIT_DEAD.
1333 read_unlock(&tasklist_lock);
1335 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1336 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1337 ? p->signal->group_exit_code : p->exit_code;
1338 if (!retval && stat_addr)
1339 retval = put_user(status, stat_addr);
1340 if (!retval && infop)
1341 retval = put_user(SIGCHLD, &infop->si_signo);
1342 if (!retval && infop)
1343 retval = put_user(0, &infop->si_errno);
1344 if (!retval && infop) {
1347 if ((status & 0x7f) == 0) {
1351 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1354 retval = put_user((short)why, &infop->si_code);
1356 retval = put_user(status, &infop->si_status);
1358 if (!retval && infop)
1359 retval = put_user(pid, &infop->si_pid);
1360 if (!retval && infop)
1361 retval = put_user(p->uid, &infop->si_uid);
1366 write_lock_irq(&tasklist_lock);
1367 /* We dropped tasklist, ptracer could die and untrace */
1370 * If this is not a detached task, notify the parent.
1371 * If it's still not detached after that, don't release
1374 if (!task_detached(p)) {
1375 do_notify_parent(p, p->exit_signal);
1376 if (!task_detached(p)) {
1377 p->exit_state = EXIT_ZOMBIE;
1381 write_unlock_irq(&tasklist_lock);
1390 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1391 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1392 * the lock and this task is uninteresting. If we return nonzero, we have
1393 * released the lock and the system call should return.
1395 static int wait_task_stopped(struct task_struct *p,
1396 int noreap, struct siginfo __user *infop,
1397 int __user *stat_addr, struct rusage __user *ru)
1399 int retval, exit_code, why;
1400 uid_t uid = 0; /* unneeded, required by compiler */
1404 spin_lock_irq(&p->sighand->siglock);
1406 if (unlikely(!task_is_stopped_or_traced(p)))
1409 if (!(p->ptrace & PT_PTRACED) && p->signal->group_stop_count > 0)
1411 * A group stop is in progress and this is the group leader.
1412 * We won't report until all threads have stopped.
1416 exit_code = p->exit_code;
1425 spin_unlock_irq(&p->sighand->siglock);
1430 * Now we are pretty sure this task is interesting.
1431 * Make sure it doesn't get reaped out from under us while we
1432 * give up the lock and then examine it below. We don't want to
1433 * keep holding onto the tasklist_lock while we call getrusage and
1434 * possibly take page faults for user memory.
1437 pid = task_pid_vnr(p);
1438 why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
1439 read_unlock(&tasklist_lock);
1441 if (unlikely(noreap))
1442 return wait_noreap_copyout(p, pid, uid,
1446 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1447 if (!retval && stat_addr)
1448 retval = put_user((exit_code << 8) | 0x7f, stat_addr);
1449 if (!retval && infop)
1450 retval = put_user(SIGCHLD, &infop->si_signo);
1451 if (!retval && infop)
1452 retval = put_user(0, &infop->si_errno);
1453 if (!retval && infop)
1454 retval = put_user((short)why, &infop->si_code);
1455 if (!retval && infop)
1456 retval = put_user(exit_code, &infop->si_status);
1457 if (!retval && infop)
1458 retval = put_user(pid, &infop->si_pid);
1459 if (!retval && infop)
1460 retval = put_user(uid, &infop->si_uid);
1470 * Handle do_wait work for one task in a live, non-stopped state.
1471 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1472 * the lock and this task is uninteresting. If we return nonzero, we have
1473 * released the lock and the system call should return.
1475 static int wait_task_continued(struct task_struct *p, int noreap,
1476 struct siginfo __user *infop,
1477 int __user *stat_addr, struct rusage __user *ru)
1483 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1486 spin_lock_irq(&p->sighand->siglock);
1487 /* Re-check with the lock held. */
1488 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1489 spin_unlock_irq(&p->sighand->siglock);
1493 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
1494 spin_unlock_irq(&p->sighand->siglock);
1496 pid = task_pid_vnr(p);
1499 read_unlock(&tasklist_lock);
1502 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1504 if (!retval && stat_addr)
1505 retval = put_user(0xffff, stat_addr);
1509 retval = wait_noreap_copyout(p, pid, uid,
1510 CLD_CONTINUED, SIGCONT,
1512 BUG_ON(retval == 0);
1518 static long do_wait(enum pid_type type, struct pid *pid, int options,
1519 struct siginfo __user *infop, int __user *stat_addr,
1520 struct rusage __user *ru)
1522 DECLARE_WAITQUEUE(wait, current);
1523 struct task_struct *tsk;
1526 add_wait_queue(¤t->signal->wait_chldexit,&wait);
1528 /* If there is nothing that can match our critier just get out */
1530 if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type])))
1534 * We will set this flag if we see any child that might later
1535 * match our criteria, even if we are not able to reap it yet.
1538 current->state = TASK_INTERRUPTIBLE;
1539 read_lock(&tasklist_lock);
1542 struct task_struct *p;
1544 list_for_each_entry(p, &tsk->children, sibling) {
1545 int ret = eligible_child(type, pid, options, p);
1549 if (unlikely(ret < 0)) {
1551 } else if (task_is_stopped_or_traced(p)) {
1553 * It's stopped now, so it might later
1554 * continue, exit, or stop again.
1557 if (!(p->ptrace & PT_PTRACED) &&
1558 !(options & WUNTRACED))
1561 retval = wait_task_stopped(p,
1562 (options & WNOWAIT), infop,
1564 } else if (p->exit_state == EXIT_ZOMBIE &&
1565 !delay_group_leader(p)) {
1567 * We don't reap group leaders with subthreads.
1569 if (!likely(options & WEXITED))
1571 retval = wait_task_zombie(p,
1572 (options & WNOWAIT), infop,
1574 } else if (p->exit_state != EXIT_DEAD) {
1576 * It's running now, so it might later
1577 * exit, stop, or stop and then continue.
1580 if (!unlikely(options & WCONTINUED))
1582 retval = wait_task_continued(p,
1583 (options & WNOWAIT), infop,
1586 if (retval != 0) /* tasklist_lock released */
1590 list_for_each_entry(p, &tsk->ptrace_children,
1592 flag = eligible_child(type, pid, options, p);
1595 if (likely(flag > 0))
1601 if (options & __WNOTHREAD)
1603 tsk = next_thread(tsk);
1604 BUG_ON(tsk->signal != current->signal);
1605 } while (tsk != current);
1606 read_unlock(&tasklist_lock);
1609 if (options & WNOHANG)
1611 retval = -ERESTARTSYS;
1612 if (signal_pending(current))
1619 current->state = TASK_RUNNING;
1620 remove_wait_queue(¤t->signal->wait_chldexit,&wait);
1626 * For a WNOHANG return, clear out all the fields
1627 * we would set so the user can easily tell the
1631 retval = put_user(0, &infop->si_signo);
1633 retval = put_user(0, &infop->si_errno);
1635 retval = put_user(0, &infop->si_code);
1637 retval = put_user(0, &infop->si_pid);
1639 retval = put_user(0, &infop->si_uid);
1641 retval = put_user(0, &infop->si_status);
1647 asmlinkage long sys_waitid(int which, pid_t upid,
1648 struct siginfo __user *infop, int options,
1649 struct rusage __user *ru)
1651 struct pid *pid = NULL;
1655 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
1657 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1670 type = PIDTYPE_PGID;
1678 if (type < PIDTYPE_MAX)
1679 pid = find_get_pid(upid);
1680 ret = do_wait(type, pid, options, infop, NULL, ru);
1683 /* avoid REGPARM breakage on x86: */
1684 asmlinkage_protect(5, ret, which, upid, infop, options, ru);
1688 asmlinkage long sys_wait4(pid_t upid, int __user *stat_addr,
1689 int options, struct rusage __user *ru)
1691 struct pid *pid = NULL;
1695 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1696 __WNOTHREAD|__WCLONE|__WALL))
1701 else if (upid < 0) {
1702 type = PIDTYPE_PGID;
1703 pid = find_get_pid(-upid);
1704 } else if (upid == 0) {
1705 type = PIDTYPE_PGID;
1706 pid = get_pid(task_pgrp(current));
1707 } else /* upid > 0 */ {
1709 pid = find_get_pid(upid);
1712 ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru);
1715 /* avoid REGPARM breakage on x86: */
1716 asmlinkage_protect(4, ret, upid, stat_addr, options, ru);
1720 #ifdef __ARCH_WANT_SYS_WAITPID
1723 * sys_waitpid() remains for compatibility. waitpid() should be
1724 * implemented by calling sys_wait4() from libc.a.
1726 asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
1728 return sys_wait4(pid, stat_addr, options, NULL);