4 * Copyright (C) 1991, 1992 Linus Torvalds
8 #include <linux/slab.h>
9 #include <linux/interrupt.h>
10 #include <linux/smp_lock.h>
11 #include <linux/module.h>
12 #include <linux/capability.h>
13 #include <linux/completion.h>
14 #include <linux/personality.h>
15 #include <linux/tty.h>
16 #include <linux/namespace.h>
17 #include <linux/key.h>
18 #include <linux/security.h>
19 #include <linux/cpu.h>
20 #include <linux/acct.h>
21 #include <linux/file.h>
22 #include <linux/binfmts.h>
23 #include <linux/ptrace.h>
24 #include <linux/profile.h>
25 #include <linux/mount.h>
26 #include <linux/proc_fs.h>
27 #include <linux/mempolicy.h>
28 #include <linux/taskstats_kern.h>
29 #include <linux/delayacct.h>
30 #include <linux/cpuset.h>
31 #include <linux/syscalls.h>
32 #include <linux/signal.h>
33 #include <linux/posix-timers.h>
34 #include <linux/cn_proc.h>
35 #include <linux/mutex.h>
36 #include <linux/futex.h>
37 #include <linux/compat.h>
38 #include <linux/pipe_fs_i.h>
39 #include <linux/audit.h> /* for audit_free() */
40 #include <linux/resource.h>
41 #include <linux/vs_limit.h>
42 #include <linux/vs_context.h>
43 #include <linux/vs_network.h>
45 #include <asm/uaccess.h>
46 #include <asm/unistd.h>
47 #include <asm/pgtable.h>
48 #include <asm/mmu_context.h>
50 extern void sem_exit (void);
51 extern struct task_struct *child_reaper;
53 static void exit_mm(struct task_struct * tsk);
55 static void __unhash_process(struct task_struct *p)
58 detach_pid(p, PIDTYPE_PID);
59 if (thread_group_leader(p)) {
60 detach_pid(p, PIDTYPE_PGID);
61 detach_pid(p, PIDTYPE_SID);
63 list_del_rcu(&p->tasks);
64 __get_cpu_var(process_counts)--;
66 list_del_rcu(&p->thread_group);
71 * This function expects the tasklist_lock write-locked.
73 static void __exit_signal(struct task_struct *tsk)
75 struct signal_struct *sig = tsk->signal;
76 struct sighand_struct *sighand;
79 BUG_ON(!atomic_read(&sig->count));
82 sighand = rcu_dereference(tsk->sighand);
83 spin_lock(&sighand->siglock);
85 posix_cpu_timers_exit(tsk);
86 if (atomic_dec_and_test(&sig->count))
87 posix_cpu_timers_exit_group(tsk);
90 * If there is any task waiting for the group exit
93 if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) {
94 wake_up_process(sig->group_exit_task);
95 sig->group_exit_task = NULL;
97 if (tsk == sig->curr_target)
98 sig->curr_target = next_thread(tsk);
100 * Accumulate here the counters for all threads but the
101 * group leader as they die, so they can be added into
102 * the process-wide totals when those are taken.
103 * The group leader stays around as a zombie as long
104 * as there are other threads. When it gets reaped,
105 * the exit.c code will add its counts into these totals.
106 * We won't ever get here for the group leader, since it
107 * will have been the last reference on the signal_struct.
109 sig->utime = cputime_add(sig->utime, tsk->utime);
110 sig->stime = cputime_add(sig->stime, tsk->stime);
111 sig->min_flt += tsk->min_flt;
112 sig->maj_flt += tsk->maj_flt;
113 sig->nvcsw += tsk->nvcsw;
114 sig->nivcsw += tsk->nivcsw;
115 sig->sched_time += tsk->sched_time;
116 sig = NULL; /* Marker for below. */
119 __unhash_process(tsk);
123 spin_unlock(&sighand->siglock);
126 __cleanup_sighand(sighand);
127 clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
128 flush_sigqueue(&tsk->pending);
130 flush_sigqueue(&sig->shared_pending);
131 __cleanup_signal(sig);
135 static void delayed_put_task_struct(struct rcu_head *rhp)
137 put_task_struct(container_of(rhp, struct task_struct, rcu));
140 void release_task(struct task_struct * p)
142 struct task_struct *leader;
145 atomic_dec(&p->user->processes);
146 write_lock_irq(&tasklist_lock);
148 BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
152 * If we are the last non-leader member of the thread
153 * group, and the leader is zombie, then notify the
154 * group leader's parent process. (if it wants notification.)
157 leader = p->group_leader;
158 if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
159 BUG_ON(leader->exit_signal == -1);
160 do_notify_parent(leader, leader->exit_signal);
162 * If we were the last child thread and the leader has
163 * exited already, and the leader's parent ignores SIGCHLD,
164 * then we are the one who should release the leader.
166 * do_notify_parent() will have marked it self-reaping in
169 zap_leader = (leader->exit_signal == -1);
173 write_unlock_irq(&tasklist_lock);
176 call_rcu(&p->rcu, delayed_put_task_struct);
179 if (unlikely(zap_leader))
184 * This checks not only the pgrp, but falls back on the pid if no
185 * satisfactory pgrp is found. I dunno - gdb doesn't work correctly
188 int session_of_pgrp(int pgrp)
190 struct task_struct *p;
193 read_lock(&tasklist_lock);
194 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
195 if (p->signal->session > 0) {
196 sid = p->signal->session;
199 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
200 p = find_task_by_pid(pgrp);
202 sid = p->signal->session;
204 read_unlock(&tasklist_lock);
210 * Determine if a process group is "orphaned", according to the POSIX
211 * definition in 2.2.2.52. Orphaned process groups are not to be affected
212 * by terminal-generated stop signals. Newly orphaned process groups are
213 * to receive a SIGHUP and a SIGCONT.
215 * "I ask you, have you ever known what it is to be an orphan?"
217 static int will_become_orphaned_pgrp(int pgrp, struct task_struct *ignored_task)
219 struct task_struct *p;
222 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
223 if (p == ignored_task
225 || p->real_parent->pid == 1)
227 if (process_group(p->real_parent) != pgrp
228 && p->real_parent->signal->session == p->signal->session) {
232 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
233 return ret; /* (sighing) "Often!" */
236 int is_orphaned_pgrp(int pgrp)
240 read_lock(&tasklist_lock);
241 retval = will_become_orphaned_pgrp(pgrp, NULL);
242 read_unlock(&tasklist_lock);
247 static int has_stopped_jobs(int pgrp)
250 struct task_struct *p;
252 do_each_task_pid(pgrp, PIDTYPE_PGID, p) {
253 if (p->state != TASK_STOPPED)
256 /* If p is stopped by a debugger on a signal that won't
257 stop it, then don't count p as stopped. This isn't
258 perfect but it's a good approximation. */
259 if (unlikely (p->ptrace)
260 && p->exit_code != SIGSTOP
261 && p->exit_code != SIGTSTP
262 && p->exit_code != SIGTTOU
263 && p->exit_code != SIGTTIN)
268 } while_each_task_pid(pgrp, PIDTYPE_PGID, p);
273 * reparent_to_init - Reparent the calling kernel thread to the init task.
275 * If a kernel thread is launched as a result of a system call, or if
276 * it ever exits, it should generally reparent itself to init so that
277 * it is correctly cleaned up on exit.
279 * The various task state such as scheduling policy and priority may have
280 * been inherited from a user process, so we reset them to sane values here.
282 * NOTE that reparent_to_init() gives the caller full capabilities.
284 static void reparent_to_init(void)
286 write_lock_irq(&tasklist_lock);
288 ptrace_unlink(current);
289 /* Reparent to init */
290 remove_parent(current);
291 current->parent = child_reaper;
292 current->real_parent = child_reaper;
295 /* Set the exit signal to SIGCHLD so we signal init on exit */
296 current->exit_signal = SIGCHLD;
298 if ((current->policy == SCHED_NORMAL ||
299 current->policy == SCHED_BATCH)
300 && (task_nice(current) < 0))
301 set_user_nice(current, 0);
305 security_task_reparent_to_init(current);
306 memcpy(current->signal->rlim, init_task.signal->rlim,
307 sizeof(current->signal->rlim));
308 atomic_inc(&(INIT_USER->__count));
309 write_unlock_irq(&tasklist_lock);
310 switch_uid(INIT_USER);
313 void __set_special_pids(pid_t session, pid_t pgrp)
315 struct task_struct *curr = current->group_leader;
317 if (curr->signal->session != session) {
318 detach_pid(curr, PIDTYPE_SID);
319 curr->signal->session = session;
320 attach_pid(curr, PIDTYPE_SID, session);
322 if (process_group(curr) != pgrp) {
323 detach_pid(curr, PIDTYPE_PGID);
324 curr->signal->pgrp = pgrp;
325 attach_pid(curr, PIDTYPE_PGID, pgrp);
329 void set_special_pids(pid_t session, pid_t pgrp)
331 write_lock_irq(&tasklist_lock);
332 __set_special_pids(session, pgrp);
333 write_unlock_irq(&tasklist_lock);
337 * Let kernel threads use this to say that they
338 * allow a certain signal (since daemonize() will
339 * have disabled all of them by default).
341 int allow_signal(int sig)
343 if (!valid_signal(sig) || sig < 1)
346 spin_lock_irq(¤t->sighand->siglock);
347 sigdelset(¤t->blocked, sig);
349 /* Kernel threads handle their own signals.
350 Let the signal code know it'll be handled, so
351 that they don't get converted to SIGKILL or
352 just silently dropped */
353 current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2;
356 spin_unlock_irq(¤t->sighand->siglock);
360 EXPORT_SYMBOL(allow_signal);
362 int disallow_signal(int sig)
364 if (!valid_signal(sig) || sig < 1)
367 spin_lock_irq(¤t->sighand->siglock);
368 sigaddset(¤t->blocked, sig);
370 spin_unlock_irq(¤t->sighand->siglock);
374 EXPORT_SYMBOL(disallow_signal);
377 * Put all the gunge required to become a kernel thread without
378 * attached user resources in one place where it belongs.
381 void daemonize(const char *name, ...)
384 struct fs_struct *fs;
387 va_start(args, name);
388 vsnprintf(current->comm, sizeof(current->comm), name, args);
392 * If we were started as result of loading a module, close all of the
393 * user space pages. We don't need them, and if we didn't close them
394 * they would be locked into memory.
398 set_special_pids(1, 1);
399 proc_clear_tty(current);
401 /* Block and flush all signals */
402 sigfillset(&blocked);
403 sigprocmask(SIG_BLOCK, &blocked, NULL);
404 flush_signals(current);
406 /* Become as one with the init task */
408 exit_fs(current); /* current->fs->count--; */
411 atomic_inc(&fs->count);
412 exit_namespace(current);
413 current->namespace = init_task.namespace;
414 get_namespace(current->namespace);
416 current->files = init_task.files;
417 atomic_inc(¤t->files->count);
422 EXPORT_SYMBOL(daemonize);
424 static void close_files(struct files_struct * files)
432 * It is safe to dereference the fd table without RCU or
433 * ->file_lock because this is the last reference to the
436 fdt = files_fdtable(files);
440 if (i >= fdt->max_fdset || i >= fdt->max_fds)
442 set = fdt->open_fds->fds_bits[j++];
445 struct file * file = xchg(&fdt->fd[i], NULL);
447 filp_close(file, files);
457 struct files_struct *get_files_struct(struct task_struct *task)
459 struct files_struct *files;
464 atomic_inc(&files->count);
470 void fastcall put_files_struct(struct files_struct *files)
474 if (atomic_dec_and_test(&files->count)) {
477 * Free the fd and fdset arrays if we expanded them.
478 * If the fdtable was embedded, pass files for freeing
479 * at the end of the RCU grace period. Otherwise,
480 * you can free files immediately.
482 fdt = files_fdtable(files);
483 if (fdt == &files->fdtab)
484 fdt->free_files = files;
486 kmem_cache_free(files_cachep, files);
491 EXPORT_SYMBOL(put_files_struct);
493 static inline void __exit_files(struct task_struct *tsk)
495 struct files_struct * files = tsk->files;
501 put_files_struct(files);
505 void exit_files(struct task_struct *tsk)
510 static inline void __put_fs_struct(struct fs_struct *fs)
512 /* No need to hold fs->lock if we are killing it */
513 if (atomic_dec_and_test(&fs->count)) {
520 mntput(fs->altrootmnt);
522 kmem_cache_free(fs_cachep, fs);
526 void put_fs_struct(struct fs_struct *fs)
531 static inline void __exit_fs(struct task_struct *tsk)
533 struct fs_struct * fs = tsk->fs;
543 void exit_fs(struct task_struct *tsk)
548 EXPORT_SYMBOL_GPL(exit_fs);
551 * Turn us into a lazy TLB process if we
554 static void exit_mm(struct task_struct * tsk)
556 struct mm_struct *mm = tsk->mm;
562 * Serialize with any possible pending coredump.
563 * We must hold mmap_sem around checking core_waiters
564 * and clearing tsk->mm. The core-inducing thread
565 * will increment core_waiters for each thread in the
566 * group with ->mm != NULL.
568 down_read(&mm->mmap_sem);
569 if (mm->core_waiters) {
570 up_read(&mm->mmap_sem);
571 down_write(&mm->mmap_sem);
572 if (!--mm->core_waiters)
573 complete(mm->core_startup_done);
574 up_write(&mm->mmap_sem);
576 wait_for_completion(&mm->core_done);
577 down_read(&mm->mmap_sem);
579 atomic_inc(&mm->mm_count);
580 BUG_ON(mm != tsk->active_mm);
581 /* more a memory barrier than a real lock */
584 up_read(&mm->mmap_sem);
585 enter_lazy_tlb(mm, current);
591 choose_new_parent(struct task_struct *p, struct task_struct *reaper)
593 /* check for reaper context */
594 vxwprintk((p->xid != reaper->xid) && (reaper != child_reaper),
595 "rogue reaper: %p[%d,#%u] <> %p[%d,#%u]",
596 p, p->pid, p->xid, reaper, reaper->pid, reaper->xid);
599 * Make sure we're not reparenting to ourselves and that
600 * the parent is not a zombie.
602 BUG_ON(p == reaper || reaper->exit_state);
603 p->real_parent = reaper;
607 reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
609 /* We don't want people slaying init. */
610 if (p->exit_signal != -1)
611 p->exit_signal = SIGCHLD;
613 if (p->pdeath_signal)
614 /* We already hold the tasklist_lock here. */
615 group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
617 /* Move the child from its dying parent to the new one. */
618 if (unlikely(traced)) {
619 /* Preserve ptrace links if someone else is tracing this child. */
620 list_del_init(&p->ptrace_list);
621 if (p->parent != p->real_parent)
622 list_add(&p->ptrace_list, &p->real_parent->ptrace_children);
624 /* If this child is being traced, then we're the one tracing it
625 * anyway, so let go of it.
629 p->parent = p->real_parent;
632 /* If we'd notified the old parent about this child's death,
633 * also notify the new parent.
635 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
636 thread_group_empty(p))
637 do_notify_parent(p, p->exit_signal);
638 else if (p->state == TASK_TRACED) {
640 * If it was at a trace stop, turn it into
641 * a normal stop since it's no longer being
649 * process group orphan check
650 * Case ii: Our child is in a different pgrp
651 * than we are, and it was the only connection
652 * outside, so the child pgrp is now orphaned.
654 if ((process_group(p) != process_group(father)) &&
655 (p->signal->session == father->signal->session)) {
656 int pgrp = process_group(p);
658 if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) {
659 __kill_pg_info(SIGHUP, SEND_SIG_PRIV, pgrp);
660 __kill_pg_info(SIGCONT, SEND_SIG_PRIV, pgrp);
666 * When we die, we re-parent all our children.
667 * Try to give them to another thread in our thread
668 * group, and if no such member exists, give it to
669 * the global child reaper process (ie "init")
672 forget_original_parent(struct task_struct *father, struct list_head *to_release)
674 struct task_struct *p, *reaper = father;
675 struct list_head *_p, *_n;
678 reaper = next_thread(reaper);
679 if (reaper == father) {
680 reaper = vx_child_reaper(father);
683 } while (reaper->exit_state);
686 * There are only two places where our children can be:
688 * - in our child list
689 * - in our ptraced child list
691 * Search them and reparent children.
693 list_for_each_safe(_p, _n, &father->children) {
695 p = list_entry(_p, struct task_struct, sibling);
699 /* if father isn't the real parent, then ptrace must be enabled */
700 BUG_ON(father != p->real_parent && !ptrace);
702 if (father == p->real_parent) {
703 /* reparent with a reaper, real father it's us */
704 choose_new_parent(p, vx_child_reaper(p));
705 reparent_thread(p, father, 0);
707 /* reparent ptraced task to its real parent */
709 if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
710 thread_group_empty(p))
711 do_notify_parent(p, p->exit_signal);
715 * if the ptraced child is a zombie with exit_signal == -1
716 * we must collect it before we exit, or it will remain
717 * zombie forever since we prevented it from self-reap itself
718 * while it was being traced by us, to be able to see it in wait4.
720 if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1))
721 list_add(&p->ptrace_list, to_release);
723 list_for_each_safe(_p, _n, &father->ptrace_children) {
724 p = list_entry(_p, struct task_struct, ptrace_list);
725 choose_new_parent(p, reaper);
726 reparent_thread(p, father, 1);
731 * Send signals to all our closest relatives so that they know
732 * to properly mourn us..
734 static void exit_notify(struct task_struct *tsk)
737 struct task_struct *t;
738 struct list_head ptrace_dead, *_p, *_n;
740 if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT)
741 && !thread_group_empty(tsk)) {
743 * This occurs when there was a race between our exit
744 * syscall and a group signal choosing us as the one to
745 * wake up. It could be that we are the only thread
746 * alerted to check for pending signals, but another thread
747 * should be woken now to take the signal since we will not.
748 * Now we'll wake all the threads in the group just to make
749 * sure someone gets all the pending signals.
751 read_lock(&tasklist_lock);
752 spin_lock_irq(&tsk->sighand->siglock);
753 for (t = next_thread(tsk); t != tsk; t = next_thread(t))
754 if (!signal_pending(t) && !(t->flags & PF_EXITING)) {
755 recalc_sigpending_tsk(t);
756 if (signal_pending(t))
757 signal_wake_up(t, 0);
759 spin_unlock_irq(&tsk->sighand->siglock);
760 read_unlock(&tasklist_lock);
763 write_lock_irq(&tasklist_lock);
766 * This does two things:
768 * A. Make init inherit all the child processes
769 * B. Check to see if any process groups have become orphaned
770 * as a result of our exiting, and if they have any stopped
771 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
774 INIT_LIST_HEAD(&ptrace_dead);
775 forget_original_parent(tsk, &ptrace_dead);
776 BUG_ON(!list_empty(&tsk->children));
777 BUG_ON(!list_empty(&tsk->ptrace_children));
780 * Check to see if any process groups have become orphaned
781 * as a result of our exiting, and if they have any stopped
782 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
784 * Case i: Our father is in a different pgrp than we are
785 * and we were the only connection outside, so our pgrp
786 * is about to become orphaned.
789 t = tsk->real_parent;
791 if ((process_group(t) != process_group(tsk)) &&
792 (t->signal->session == tsk->signal->session) &&
793 will_become_orphaned_pgrp(process_group(tsk), tsk) &&
794 has_stopped_jobs(process_group(tsk))) {
795 __kill_pg_info(SIGHUP, SEND_SIG_PRIV, process_group(tsk));
796 __kill_pg_info(SIGCONT, SEND_SIG_PRIV, process_group(tsk));
799 /* Let father know we died
801 * Thread signals are configurable, but you aren't going to use
802 * that to send signals to arbitary processes.
803 * That stops right now.
805 * If the parent exec id doesn't match the exec id we saved
806 * when we started then we know the parent has changed security
809 * If our self_exec id doesn't match our parent_exec_id then
810 * we have changed execution domain as these two values started
811 * the same after a fork.
815 if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 &&
816 ( tsk->parent_exec_id != t->self_exec_id ||
817 tsk->self_exec_id != tsk->parent_exec_id)
818 && !capable(CAP_KILL))
819 tsk->exit_signal = SIGCHLD;
822 /* If something other than our normal parent is ptracing us, then
823 * send it a SIGCHLD instead of honoring exit_signal. exit_signal
824 * only has special meaning to our real parent.
826 if (tsk->exit_signal != -1 && thread_group_empty(tsk)) {
827 int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD;
828 do_notify_parent(tsk, signal);
829 } else if (tsk->ptrace) {
830 do_notify_parent(tsk, SIGCHLD);
834 if (tsk->exit_signal == -1 &&
835 (likely(tsk->ptrace == 0) ||
836 unlikely(tsk->parent->signal->flags & SIGNAL_GROUP_EXIT)))
838 tsk->exit_state = state;
840 write_unlock_irq(&tasklist_lock);
842 list_for_each_safe(_p, _n, &ptrace_dead) {
844 t = list_entry(_p, struct task_struct, ptrace_list);
848 /* If the process is dead, release it - nobody will wait for it */
849 if (state == EXIT_DEAD)
853 fastcall NORET_TYPE void do_exit(long code)
855 struct task_struct *tsk = current;
856 struct taskstats *tidstats;
860 profile_task_exit(tsk);
862 WARN_ON(atomic_read(&tsk->fs_excl));
864 if (unlikely(in_interrupt()))
865 panic("Aiee, killing interrupt handler!");
866 if (unlikely(!tsk->pid))
867 panic("Attempted to kill the idle task!");
868 if (unlikely(tsk == child_reaper))
869 panic("Attempted to kill init!");
871 if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
872 current->ptrace_message = code;
873 ptrace_notify((PTRACE_EVENT_EXIT << 8) | SIGTRAP);
877 * We're taking recursive faults here in do_exit. Safest is to just
878 * leave this task alone and wait for reboot.
880 if (unlikely(tsk->flags & PF_EXITING)) {
882 "Fixing recursive fault but reboot is needed!\n");
885 set_current_state(TASK_UNINTERRUPTIBLE);
889 tsk->flags |= PF_EXITING;
891 if (unlikely(in_atomic()))
892 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
893 current->comm, current->pid,
896 taskstats_exit_alloc(&tidstats, &mycpu);
898 acct_update_integrals(tsk);
900 update_hiwater_rss(tsk->mm);
901 update_hiwater_vm(tsk->mm);
903 group_dead = atomic_dec_and_test(&tsk->signal->live);
905 hrtimer_cancel(&tsk->signal->real_timer);
906 exit_itimers(tsk->signal);
909 if (current->tux_info) {
910 #ifdef CONFIG_TUX_DEBUG
911 printk("Possibly unexpected TUX-thread exit(%ld) at %p?\n",
912 code, __builtin_return_address(0));
917 acct_collect(code, group_dead);
918 if (unlikely(tsk->robust_list))
919 exit_robust_list(tsk);
920 #if defined(CONFIG_FUTEX) && defined(CONFIG_COMPAT)
921 if (unlikely(tsk->compat_robust_list))
922 compat_exit_robust_list(tsk);
924 if (unlikely(tsk->audit_context))
926 taskstats_exit_send(tsk, tidstats, group_dead, mycpu);
927 taskstats_exit_free(tidstats);
941 if (group_dead && tsk->signal->leader)
942 disassociate_ctty(1);
944 module_put(task_thread_info(tsk)->exec_domain->module);
946 module_put(tsk->binfmt->module);
948 tsk->exit_code = code;
949 proc_exit_connector(tsk);
950 /* needs to stay before exit_notify() */
951 exit_vx_info_early(tsk, code);
954 mpol_free(tsk->mempolicy);
955 tsk->mempolicy = NULL;
958 * This must happen late, after the PID is not
961 if (unlikely(!list_empty(&tsk->pi_state_list)))
962 exit_pi_state_list(tsk);
963 if (unlikely(current->pi_state_cache))
964 kfree(current->pi_state_cache);
966 * Make sure we are holding no locks:
968 debug_check_no_locks_held(tsk);
973 if (tsk->splice_pipe)
974 __free_pipe_info(tsk->splice_pipe);
976 /* needs to stay after exit_notify() */
977 exit_vx_info(tsk, code);
980 /* PF_DEAD causes final put_task_struct after we schedule. */
982 BUG_ON(tsk->flags & PF_DEAD);
983 tsk->flags |= PF_DEAD;
987 /* Avoid "noreturn function does return". */
991 EXPORT_SYMBOL_GPL(do_exit);
993 NORET_TYPE void complete_and_exit(struct completion *comp, long code)
1001 EXPORT_SYMBOL(complete_and_exit);
1003 asmlinkage long sys_exit(int error_code)
1005 do_exit((error_code&0xff)<<8);
1009 * Take down every thread in the group. This is called by fatal signals
1010 * as well as by sys_exit_group (below).
1013 do_group_exit(int exit_code)
1015 BUG_ON(exit_code & 0x80); /* core dumps don't get here */
1017 if (current->signal->flags & SIGNAL_GROUP_EXIT)
1018 exit_code = current->signal->group_exit_code;
1019 else if (!thread_group_empty(current)) {
1020 struct signal_struct *const sig = current->signal;
1021 struct sighand_struct *const sighand = current->sighand;
1022 spin_lock_irq(&sighand->siglock);
1023 if (sig->flags & SIGNAL_GROUP_EXIT)
1024 /* Another thread got here before we took the lock. */
1025 exit_code = sig->group_exit_code;
1027 sig->group_exit_code = exit_code;
1028 zap_other_threads(current);
1030 spin_unlock_irq(&sighand->siglock);
1038 * this kills every thread in the thread group. Note that any externally
1039 * wait4()-ing process will get the correct exit code - even if this
1040 * thread is not the thread group leader.
1042 asmlinkage void sys_exit_group(int error_code)
1044 do_group_exit((error_code & 0xff) << 8);
1047 static int eligible_child(pid_t pid, int options, struct task_struct *p)
1053 if (process_group(p) != process_group(current))
1055 } else if (pid != -1) {
1056 if (process_group(p) != -pid)
1061 * Do not consider detached threads that are
1064 if (p->exit_signal == -1 && !p->ptrace)
1067 /* Wait for all children (clone and not) if __WALL is set;
1068 * otherwise, wait for clone children *only* if __WCLONE is
1069 * set; otherwise, wait for non-clone children *only*. (Note:
1070 * A "clone" child here is one that reports to its parent
1071 * using a signal other than SIGCHLD.) */
1072 if (((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
1073 && !(options & __WALL))
1076 * Do not consider thread group leaders that are
1077 * in a non-empty thread group:
1079 if (delay_group_leader(p))
1082 if (security_task_wait(p))
1088 static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
1089 int why, int status,
1090 struct siginfo __user *infop,
1091 struct rusage __user *rusagep)
1093 int retval = rusagep ? getrusage(p, RUSAGE_BOTH, rusagep) : 0;
1097 retval = put_user(SIGCHLD, &infop->si_signo);
1099 retval = put_user(0, &infop->si_errno);
1101 retval = put_user((short)why, &infop->si_code);
1103 retval = put_user(pid, &infop->si_pid);
1105 retval = put_user(uid, &infop->si_uid);
1107 retval = put_user(status, &infop->si_status);
1114 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1115 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1116 * the lock and this task is uninteresting. If we return nonzero, we have
1117 * released the lock and the system call should return.
1119 static int wait_task_zombie(struct task_struct *p, int noreap,
1120 struct siginfo __user *infop,
1121 int __user *stat_addr, struct rusage __user *ru)
1123 unsigned long state;
1127 if (unlikely(noreap)) {
1130 int exit_code = p->exit_code;
1133 if (unlikely(p->exit_state != EXIT_ZOMBIE))
1135 if (unlikely(p->exit_signal == -1 && p->ptrace == 0))
1138 read_unlock(&tasklist_lock);
1139 if ((exit_code & 0x7f) == 0) {
1141 status = exit_code >> 8;
1143 why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED;
1144 status = exit_code & 0x7f;
1146 return wait_noreap_copyout(p, pid, uid, why,
1151 * Try to move the task's state to DEAD
1152 * only one thread is allowed to do this:
1154 state = xchg(&p->exit_state, EXIT_DEAD);
1155 if (state != EXIT_ZOMBIE) {
1156 BUG_ON(state != EXIT_DEAD);
1159 if (unlikely(p->exit_signal == -1 && p->ptrace == 0)) {
1161 * This can only happen in a race with a ptraced thread
1162 * dying on another processor.
1167 if (likely(p->real_parent == p->parent) && likely(p->signal)) {
1168 struct signal_struct *psig;
1169 struct signal_struct *sig;
1172 * The resource counters for the group leader are in its
1173 * own task_struct. Those for dead threads in the group
1174 * are in its signal_struct, as are those for the child
1175 * processes it has previously reaped. All these
1176 * accumulate in the parent's signal_struct c* fields.
1178 * We don't bother to take a lock here to protect these
1179 * p->signal fields, because they are only touched by
1180 * __exit_signal, which runs with tasklist_lock
1181 * write-locked anyway, and so is excluded here. We do
1182 * need to protect the access to p->parent->signal fields,
1183 * as other threads in the parent group can be right
1184 * here reaping other children at the same time.
1186 spin_lock_irq(&p->parent->sighand->siglock);
1187 psig = p->parent->signal;
1190 cputime_add(psig->cutime,
1191 cputime_add(p->utime,
1192 cputime_add(sig->utime,
1195 cputime_add(psig->cstime,
1196 cputime_add(p->stime,
1197 cputime_add(sig->stime,
1200 p->min_flt + sig->min_flt + sig->cmin_flt;
1202 p->maj_flt + sig->maj_flt + sig->cmaj_flt;
1204 p->nvcsw + sig->nvcsw + sig->cnvcsw;
1206 p->nivcsw + sig->nivcsw + sig->cnivcsw;
1207 spin_unlock_irq(&p->parent->sighand->siglock);
1211 * Now we are sure this task is interesting, and no other
1212 * thread can reap it because we set its state to EXIT_DEAD.
1214 read_unlock(&tasklist_lock);
1216 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1217 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1218 ? p->signal->group_exit_code : p->exit_code;
1219 if (!retval && stat_addr)
1220 retval = put_user(status, stat_addr);
1221 if (!retval && infop)
1222 retval = put_user(SIGCHLD, &infop->si_signo);
1223 if (!retval && infop)
1224 retval = put_user(0, &infop->si_errno);
1225 if (!retval && infop) {
1228 if ((status & 0x7f) == 0) {
1232 why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1235 retval = put_user((short)why, &infop->si_code);
1237 retval = put_user(status, &infop->si_status);
1239 if (!retval && infop)
1240 retval = put_user(p->pid, &infop->si_pid);
1241 if (!retval && infop)
1242 retval = put_user(p->uid, &infop->si_uid);
1244 // TODO: is this safe?
1245 p->exit_state = EXIT_ZOMBIE;
1249 if (p->real_parent != p->parent) {
1250 write_lock_irq(&tasklist_lock);
1251 /* Double-check with lock held. */
1252 if (p->real_parent != p->parent) {
1254 // TODO: is this safe?
1255 p->exit_state = EXIT_ZOMBIE;
1257 * If this is not a detached task, notify the parent.
1258 * If it's still not detached after that, don't release
1261 if (p->exit_signal != -1) {
1262 do_notify_parent(p, p->exit_signal);
1263 if (p->exit_signal != -1)
1267 write_unlock_irq(&tasklist_lock);
1276 * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold
1277 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1278 * the lock and this task is uninteresting. If we return nonzero, we have
1279 * released the lock and the system call should return.
1281 static int wait_task_stopped(struct task_struct *p, int delayed_group_leader,
1282 int noreap, struct siginfo __user *infop,
1283 int __user *stat_addr, struct rusage __user *ru)
1285 int retval, exit_code;
1289 if (delayed_group_leader && !(p->ptrace & PT_PTRACED) &&
1290 p->signal && p->signal->group_stop_count > 0)
1292 * A group stop is in progress and this is the group leader.
1293 * We won't report until all threads have stopped.
1298 * Now we are pretty sure this task is interesting.
1299 * Make sure it doesn't get reaped out from under us while we
1300 * give up the lock and then examine it below. We don't want to
1301 * keep holding onto the tasklist_lock while we call getrusage and
1302 * possibly take page faults for user memory.
1305 read_unlock(&tasklist_lock);
1307 if (unlikely(noreap)) {
1310 int why = (p->ptrace & PT_PTRACED) ? CLD_TRAPPED : CLD_STOPPED;
1312 exit_code = p->exit_code;
1313 if (unlikely(!exit_code) ||
1314 unlikely(p->state & TASK_TRACED))
1316 return wait_noreap_copyout(p, pid, uid,
1317 why, (exit_code << 8) | 0x7f,
1321 write_lock_irq(&tasklist_lock);
1324 * This uses xchg to be atomic with the thread resuming and setting
1325 * it. It must also be done with the write lock held to prevent a
1326 * race with the EXIT_ZOMBIE case.
1328 exit_code = xchg(&p->exit_code, 0);
1329 if (unlikely(p->exit_state)) {
1331 * The task resumed and then died. Let the next iteration
1332 * catch it in EXIT_ZOMBIE. Note that exit_code might
1333 * already be zero here if it resumed and did _exit(0).
1334 * The task itself is dead and won't touch exit_code again;
1335 * other processors in this function are locked out.
1337 p->exit_code = exit_code;
1340 if (unlikely(exit_code == 0)) {
1342 * Another thread in this function got to it first, or it
1343 * resumed, or it resumed and then died.
1345 write_unlock_irq(&tasklist_lock);
1349 * We are returning to the wait loop without having successfully
1350 * removed the process and having released the lock. We cannot
1351 * continue, since the "p" task pointer is potentially stale.
1353 * Return -EAGAIN, and do_wait() will restart the loop from the
1354 * beginning. Do _not_ re-acquire the lock.
1359 /* move to end of parent's list to avoid starvation */
1363 write_unlock_irq(&tasklist_lock);
1365 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1366 if (!retval && stat_addr)
1367 retval = put_user((exit_code << 8) | 0x7f, stat_addr);
1368 if (!retval && infop)
1369 retval = put_user(SIGCHLD, &infop->si_signo);
1370 if (!retval && infop)
1371 retval = put_user(0, &infop->si_errno);
1372 if (!retval && infop)
1373 retval = put_user((short)((p->ptrace & PT_PTRACED)
1374 ? CLD_TRAPPED : CLD_STOPPED),
1376 if (!retval && infop)
1377 retval = put_user(exit_code, &infop->si_status);
1378 if (!retval && infop)
1379 retval = put_user(p->pid, &infop->si_pid);
1380 if (!retval && infop)
1381 retval = put_user(p->uid, &infop->si_uid);
1391 * Handle do_wait work for one task in a live, non-stopped state.
1392 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1393 * the lock and this task is uninteresting. If we return nonzero, we have
1394 * released the lock and the system call should return.
1396 static int wait_task_continued(struct task_struct *p, int noreap,
1397 struct siginfo __user *infop,
1398 int __user *stat_addr, struct rusage __user *ru)
1404 if (unlikely(!p->signal))
1407 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1410 spin_lock_irq(&p->sighand->siglock);
1411 /* Re-check with the lock held. */
1412 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1413 spin_unlock_irq(&p->sighand->siglock);
1417 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
1418 spin_unlock_irq(&p->sighand->siglock);
1423 read_unlock(&tasklist_lock);
1426 retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
1428 if (!retval && stat_addr)
1429 retval = put_user(0xffff, stat_addr);
1433 retval = wait_noreap_copyout(p, pid, uid,
1434 CLD_CONTINUED, SIGCONT,
1436 BUG_ON(retval == 0);
1443 static inline int my_ptrace_child(struct task_struct *p)
1445 if (!(p->ptrace & PT_PTRACED))
1447 if (!(p->ptrace & PT_ATTACHED))
1450 * This child was PTRACE_ATTACH'd. We should be seeing it only if
1451 * we are the attacher. If we are the real parent, this is a race
1452 * inside ptrace_attach. It is waiting for the tasklist_lock,
1453 * which we have to switch the parent links, but has already set
1454 * the flags in p->ptrace.
1456 return (p->parent != p->real_parent);
1459 static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
1460 int __user *stat_addr, struct rusage __user *ru)
1462 DECLARE_WAITQUEUE(wait, current);
1463 struct task_struct *tsk;
1466 add_wait_queue(¤t->signal->wait_chldexit,&wait);
1469 * We will set this flag if we see any child that might later
1470 * match our criteria, even if we are not able to reap it yet.
1473 current->state = TASK_INTERRUPTIBLE;
1474 read_lock(&tasklist_lock);
1477 struct task_struct *p;
1478 struct list_head *_p;
1481 list_for_each(_p,&tsk->children) {
1482 p = list_entry(_p, struct task_struct, sibling);
1484 ret = eligible_child(pid, options, p);
1491 * When we hit the race with PTRACE_ATTACH,
1492 * we will not report this child. But the
1493 * race means it has not yet been moved to
1494 * our ptrace_children list, so we need to
1495 * set the flag here to avoid a spurious ECHILD
1496 * when the race happens with the only child.
1499 if (!my_ptrace_child(p))
1504 * It's stopped now, so it might later
1505 * continue, exit, or stop again.
1508 if (!(options & WUNTRACED) &&
1509 !my_ptrace_child(p))
1511 retval = wait_task_stopped(p, ret == 2,
1512 (options & WNOWAIT),
1515 if (retval == -EAGAIN)
1517 if (retval != 0) /* He released the lock. */
1522 if (p->exit_state == EXIT_DEAD)
1524 // case EXIT_ZOMBIE:
1525 if (p->exit_state == EXIT_ZOMBIE) {
1527 * Eligible but we cannot release
1531 goto check_continued;
1532 if (!likely(options & WEXITED))
1534 retval = wait_task_zombie(
1535 p, (options & WNOWAIT),
1536 infop, stat_addr, ru);
1537 /* He released the lock. */
1544 * It's running now, so it might later
1545 * exit, stop, or stop and then continue.
1548 if (!unlikely(options & WCONTINUED))
1550 retval = wait_task_continued(
1551 p, (options & WNOWAIT),
1552 infop, stat_addr, ru);
1553 if (retval != 0) /* He released the lock. */
1559 list_for_each(_p, &tsk->ptrace_children) {
1560 p = list_entry(_p, struct task_struct,
1562 if (!eligible_child(pid, options, p))
1568 if (options & __WNOTHREAD)
1570 tsk = next_thread(tsk);
1571 BUG_ON(tsk->signal != current->signal);
1572 } while (tsk != current);
1574 read_unlock(&tasklist_lock);
1577 if (options & WNOHANG)
1579 retval = -ERESTARTSYS;
1580 if (signal_pending(current))
1587 current->state = TASK_RUNNING;
1588 remove_wait_queue(¤t->signal->wait_chldexit,&wait);
1594 * For a WNOHANG return, clear out all the fields
1595 * we would set so the user can easily tell the
1599 retval = put_user(0, &infop->si_signo);
1601 retval = put_user(0, &infop->si_errno);
1603 retval = put_user(0, &infop->si_code);
1605 retval = put_user(0, &infop->si_pid);
1607 retval = put_user(0, &infop->si_uid);
1609 retval = put_user(0, &infop->si_status);
1615 asmlinkage long sys_waitid(int which, pid_t pid,
1616 struct siginfo __user *infop, int options,
1617 struct rusage __user *ru)
1621 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
1623 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1643 ret = do_wait(pid, options, infop, NULL, ru);
1645 /* avoid REGPARM breakage on x86: */
1646 prevent_tail_call(ret);
1650 asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr,
1651 int options, struct rusage __user *ru)
1655 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1656 __WNOTHREAD|__WCLONE|__WALL))
1658 ret = do_wait(pid, options | WEXITED, NULL, stat_addr, ru);
1660 /* avoid REGPARM breakage on x86: */
1661 prevent_tail_call(ret);
1665 #ifdef __ARCH_WANT_SYS_WAITPID
1668 * sys_waitpid() remains for compatibility. waitpid() should be
1669 * implemented by calling sys_wait4() from libc.a.
1671 asmlinkage long sys_waitpid(pid_t pid, int __user *stat_addr, int options)
1673 return sys_wait4(pid, stat_addr, options, NULL);