2 * linux/kernel/signal.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
8 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
9 * Changes to use preallocated sigqueue structures
10 * to allow signals to be sent reliably.
13 #include <linux/slab.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/sched.h>
18 #include <linux/tty.h>
19 #include <linux/binfmts.h>
20 #include <linux/security.h>
21 #include <linux/syscalls.h>
22 #include <linux/ptrace.h>
23 #include <linux/signal.h>
24 #include <linux/signalfd.h>
25 #include <linux/ratelimit.h>
26 #include <linux/tracehook.h>
27 #include <linux/capability.h>
28 #include <linux/freezer.h>
29 #include <linux/pid_namespace.h>
30 #include <linux/nsproxy.h>
31 #define CREATE_TRACE_POINTS
32 #include <trace/events/signal.h>
34 #include <asm/param.h>
35 #include <asm/uaccess.h>
36 #include <asm/unistd.h>
37 #include <asm/siginfo.h>
38 #include "audit.h" /* audit_signal_info() */
41 * SLAB caches for signal bits.
44 static struct kmem_cache *sigqueue_cachep;
46 int print_fatal_signals __read_mostly;
48 static void __user *sig_handler(struct task_struct *t, int sig)
50 return t->sighand->action[sig - 1].sa.sa_handler;
53 static int sig_handler_ignored(void __user *handler, int sig)
55 /* Is it explicitly or implicitly ignored? */
56 return handler == SIG_IGN ||
57 (handler == SIG_DFL && sig_kernel_ignore(sig));
60 static int sig_task_ignored(struct task_struct *t, int sig,
65 handler = sig_handler(t, sig);
67 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
68 handler == SIG_DFL && !from_ancestor_ns)
71 return sig_handler_ignored(handler, sig);
74 static int sig_ignored(struct task_struct *t, int sig, int from_ancestor_ns)
77 * Blocked signals are never ignored, since the
78 * signal handler may change by the time it is
81 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
84 if (!sig_task_ignored(t, sig, from_ancestor_ns))
88 * Tracers may want to know about even ignored signals.
90 return !tracehook_consider_ignored_signal(t, sig);
94 * Re-calculate pending state from the set of locally pending
95 * signals, globally pending signals, and blocked signals.
97 static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
102 switch (_NSIG_WORDS) {
104 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
105 ready |= signal->sig[i] &~ blocked->sig[i];
108 case 4: ready = signal->sig[3] &~ blocked->sig[3];
109 ready |= signal->sig[2] &~ blocked->sig[2];
110 ready |= signal->sig[1] &~ blocked->sig[1];
111 ready |= signal->sig[0] &~ blocked->sig[0];
114 case 2: ready = signal->sig[1] &~ blocked->sig[1];
115 ready |= signal->sig[0] &~ blocked->sig[0];
118 case 1: ready = signal->sig[0] &~ blocked->sig[0];
123 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
125 static int recalc_sigpending_tsk(struct task_struct *t)
127 if ((t->group_stop & GROUP_STOP_PENDING) ||
128 PENDING(&t->pending, &t->blocked) ||
129 PENDING(&t->signal->shared_pending, &t->blocked)) {
130 set_tsk_thread_flag(t, TIF_SIGPENDING);
134 * We must never clear the flag in another thread, or in current
135 * when it's possible the current syscall is returning -ERESTART*.
136 * So we don't clear it here, and only callers who know they should do.
142 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
143 * This is superfluous when called on current, the wakeup is a harmless no-op.
145 void recalc_sigpending_and_wake(struct task_struct *t)
147 if (recalc_sigpending_tsk(t))
148 signal_wake_up(t, 0);
151 void recalc_sigpending(void)
153 if (unlikely(tracehook_force_sigpending()))
154 set_thread_flag(TIF_SIGPENDING);
155 else if (!recalc_sigpending_tsk(current) && !freezing(current))
156 clear_thread_flag(TIF_SIGPENDING);
160 /* Given the mask, find the first available signal that should be serviced. */
162 #define SYNCHRONOUS_MASK \
163 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
164 sigmask(SIGTRAP) | sigmask(SIGFPE))
166 int next_signal(struct sigpending *pending, sigset_t *mask)
168 unsigned long i, *s, *m, x;
171 s = pending->signal.sig;
175 * Handle the first word specially: it contains the
176 * synchronous signals that need to be dequeued first.
180 if (x & SYNCHRONOUS_MASK)
181 x &= SYNCHRONOUS_MASK;
186 switch (_NSIG_WORDS) {
188 for (i = 1; i < _NSIG_WORDS; ++i) {
192 sig = ffz(~x) + i*_NSIG_BPW + 1;
201 sig = ffz(~x) + _NSIG_BPW + 1;
212 static inline void print_dropped_signal(int sig)
214 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
216 if (!print_fatal_signals)
219 if (!__ratelimit(&ratelimit_state))
222 printk(KERN_INFO "%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
223 current->comm, current->pid, sig);
227 * task_clear_group_stop_pending - clear pending group stop
230 * Clear group stop states for @task.
233 * Must be called with @task->sighand->siglock held.
235 void task_clear_group_stop_pending(struct task_struct *task)
237 task->group_stop &= ~(GROUP_STOP_PENDING | GROUP_STOP_CONSUME);
241 * task_participate_group_stop - participate in a group stop
242 * @task: task participating in a group stop
244 * @task has GROUP_STOP_PENDING set and is participating in a group stop.
245 * Group stop states are cleared and the group stop count is consumed if
246 * %GROUP_STOP_CONSUME was set. If the consumption completes the group
247 * stop, the appropriate %SIGNAL_* flags are set.
250 * Must be called with @task->sighand->siglock held.
252 static bool task_participate_group_stop(struct task_struct *task)
254 struct signal_struct *sig = task->signal;
255 bool consume = task->group_stop & GROUP_STOP_CONSUME;
257 WARN_ON_ONCE(!(task->group_stop & GROUP_STOP_PENDING));
259 task_clear_group_stop_pending(task);
264 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
265 sig->group_stop_count--;
267 if (!sig->group_stop_count) {
268 sig->flags = SIGNAL_STOP_STOPPED;
275 * allocate a new signal queue record
276 * - this may be called without locks if and only if t == current, otherwise an
277 * appopriate lock must be held to stop the target task from exiting
279 static struct sigqueue *
280 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
282 struct sigqueue *q = NULL;
283 struct user_struct *user;
286 * Protect access to @t credentials. This can go away when all
287 * callers hold rcu read lock.
290 user = get_uid(__task_cred(t)->user);
291 atomic_inc(&user->sigpending);
294 if (override_rlimit ||
295 atomic_read(&user->sigpending) <=
296 task_rlimit(t, RLIMIT_SIGPENDING)) {
297 q = kmem_cache_alloc(sigqueue_cachep, flags);
299 print_dropped_signal(sig);
302 if (unlikely(q == NULL)) {
303 atomic_dec(&user->sigpending);
306 INIT_LIST_HEAD(&q->list);
314 static void __sigqueue_free(struct sigqueue *q)
316 if (q->flags & SIGQUEUE_PREALLOC)
318 atomic_dec(&q->user->sigpending);
320 kmem_cache_free(sigqueue_cachep, q);
323 void flush_sigqueue(struct sigpending *queue)
327 sigemptyset(&queue->signal);
328 while (!list_empty(&queue->list)) {
329 q = list_entry(queue->list.next, struct sigqueue , list);
330 list_del_init(&q->list);
336 * Flush all pending signals for a task.
338 void __flush_signals(struct task_struct *t)
340 clear_tsk_thread_flag(t, TIF_SIGPENDING);
341 flush_sigqueue(&t->pending);
342 flush_sigqueue(&t->signal->shared_pending);
345 void flush_signals(struct task_struct *t)
349 spin_lock_irqsave(&t->sighand->siglock, flags);
351 spin_unlock_irqrestore(&t->sighand->siglock, flags);
354 static void __flush_itimer_signals(struct sigpending *pending)
356 sigset_t signal, retain;
357 struct sigqueue *q, *n;
359 signal = pending->signal;
360 sigemptyset(&retain);
362 list_for_each_entry_safe(q, n, &pending->list, list) {
363 int sig = q->info.si_signo;
365 if (likely(q->info.si_code != SI_TIMER)) {
366 sigaddset(&retain, sig);
368 sigdelset(&signal, sig);
369 list_del_init(&q->list);
374 sigorsets(&pending->signal, &signal, &retain);
377 void flush_itimer_signals(void)
379 struct task_struct *tsk = current;
382 spin_lock_irqsave(&tsk->sighand->siglock, flags);
383 __flush_itimer_signals(&tsk->pending);
384 __flush_itimer_signals(&tsk->signal->shared_pending);
385 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
388 void ignore_signals(struct task_struct *t)
392 for (i = 0; i < _NSIG; ++i)
393 t->sighand->action[i].sa.sa_handler = SIG_IGN;
399 * Flush all handlers for a task.
403 flush_signal_handlers(struct task_struct *t, int force_default)
406 struct k_sigaction *ka = &t->sighand->action[0];
407 for (i = _NSIG ; i != 0 ; i--) {
408 if (force_default || ka->sa.sa_handler != SIG_IGN)
409 ka->sa.sa_handler = SIG_DFL;
411 sigemptyset(&ka->sa.sa_mask);
416 int unhandled_signal(struct task_struct *tsk, int sig)
418 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
419 if (is_global_init(tsk))
421 if (handler != SIG_IGN && handler != SIG_DFL)
423 return !tracehook_consider_fatal_signal(tsk, sig);
427 /* Notify the system that a driver wants to block all signals for this
428 * process, and wants to be notified if any signals at all were to be
429 * sent/acted upon. If the notifier routine returns non-zero, then the
430 * signal will be acted upon after all. If the notifier routine returns 0,
431 * then then signal will be blocked. Only one block per process is
432 * allowed. priv is a pointer to private data that the notifier routine
433 * can use to determine if the signal should be blocked or not. */
436 block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
440 spin_lock_irqsave(¤t->sighand->siglock, flags);
441 current->notifier_mask = mask;
442 current->notifier_data = priv;
443 current->notifier = notifier;
444 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
447 /* Notify the system that blocking has ended. */
450 unblock_all_signals(void)
454 spin_lock_irqsave(¤t->sighand->siglock, flags);
455 current->notifier = NULL;
456 current->notifier_data = NULL;
458 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
461 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
463 struct sigqueue *q, *first = NULL;
466 * Collect the siginfo appropriate to this signal. Check if
467 * there is another siginfo for the same signal.
469 list_for_each_entry(q, &list->list, list) {
470 if (q->info.si_signo == sig) {
477 sigdelset(&list->signal, sig);
481 list_del_init(&first->list);
482 copy_siginfo(info, &first->info);
483 __sigqueue_free(first);
485 /* Ok, it wasn't in the queue. This must be
486 a fast-pathed signal or we must have been
487 out of queue space. So zero out the info.
489 info->si_signo = sig;
491 info->si_code = SI_USER;
497 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
500 int sig = next_signal(pending, mask);
503 if (current->notifier) {
504 if (sigismember(current->notifier_mask, sig)) {
505 if (!(current->notifier)(current->notifier_data)) {
506 clear_thread_flag(TIF_SIGPENDING);
512 collect_signal(sig, pending, info);
519 * Dequeue a signal and return the element to the caller, which is
520 * expected to free it.
522 * All callers have to hold the siglock.
524 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
528 /* We only dequeue private signals from ourselves, we don't let
529 * signalfd steal them
531 signr = __dequeue_signal(&tsk->pending, mask, info);
533 signr = __dequeue_signal(&tsk->signal->shared_pending,
538 * itimers are process shared and we restart periodic
539 * itimers in the signal delivery path to prevent DoS
540 * attacks in the high resolution timer case. This is
541 * compliant with the old way of self restarting
542 * itimers, as the SIGALRM is a legacy signal and only
543 * queued once. Changing the restart behaviour to
544 * restart the timer in the signal dequeue path is
545 * reducing the timer noise on heavy loaded !highres
548 if (unlikely(signr == SIGALRM)) {
549 struct hrtimer *tmr = &tsk->signal->real_timer;
551 if (!hrtimer_is_queued(tmr) &&
552 tsk->signal->it_real_incr.tv64 != 0) {
553 hrtimer_forward(tmr, tmr->base->get_time(),
554 tsk->signal->it_real_incr);
555 hrtimer_restart(tmr);
564 if (unlikely(sig_kernel_stop(signr))) {
566 * Set a marker that we have dequeued a stop signal. Our
567 * caller might release the siglock and then the pending
568 * stop signal it is about to process is no longer in the
569 * pending bitmasks, but must still be cleared by a SIGCONT
570 * (and overruled by a SIGKILL). So those cases clear this
571 * shared flag after we've set it. Note that this flag may
572 * remain set after the signal we return is ignored or
573 * handled. That doesn't matter because its only purpose
574 * is to alert stop-signal processing code when another
575 * processor has come along and cleared the flag.
577 tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
579 if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
581 * Release the siglock to ensure proper locking order
582 * of timer locks outside of siglocks. Note, we leave
583 * irqs disabled here, since the posix-timers code is
584 * about to disable them again anyway.
586 spin_unlock(&tsk->sighand->siglock);
587 do_schedule_next_timer(info);
588 spin_lock(&tsk->sighand->siglock);
594 * Tell a process that it has a new active signal..
596 * NOTE! we rely on the previous spin_lock to
597 * lock interrupts for us! We can only be called with
598 * "siglock" held, and the local interrupt must
599 * have been disabled when that got acquired!
601 * No need to set need_resched since signal event passing
602 * goes through ->blocked
604 void signal_wake_up(struct task_struct *t, int resume)
608 set_tsk_thread_flag(t, TIF_SIGPENDING);
611 * For SIGKILL, we want to wake it up in the stopped/traced/killable
612 * case. We don't check t->state here because there is a race with it
613 * executing another processor and just now entering stopped state.
614 * By using wake_up_state, we ensure the process will wake up and
615 * handle its death signal.
617 mask = TASK_INTERRUPTIBLE;
619 mask |= TASK_WAKEKILL;
620 if (!wake_up_state(t, mask))
625 * Remove signals in mask from the pending set and queue.
626 * Returns 1 if any signals were found.
628 * All callers must be holding the siglock.
630 * This version takes a sigset mask and looks at all signals,
631 * not just those in the first mask word.
633 static int rm_from_queue_full(sigset_t *mask, struct sigpending *s)
635 struct sigqueue *q, *n;
638 sigandsets(&m, mask, &s->signal);
639 if (sigisemptyset(&m))
642 signandsets(&s->signal, &s->signal, mask);
643 list_for_each_entry_safe(q, n, &s->list, list) {
644 if (sigismember(mask, q->info.si_signo)) {
645 list_del_init(&q->list);
652 * Remove signals in mask from the pending set and queue.
653 * Returns 1 if any signals were found.
655 * All callers must be holding the siglock.
657 static int rm_from_queue(unsigned long mask, struct sigpending *s)
659 struct sigqueue *q, *n;
661 if (!sigtestsetmask(&s->signal, mask))
664 sigdelsetmask(&s->signal, mask);
665 list_for_each_entry_safe(q, n, &s->list, list) {
666 if (q->info.si_signo < SIGRTMIN &&
667 (mask & sigmask(q->info.si_signo))) {
668 list_del_init(&q->list);
675 static inline int is_si_special(const struct siginfo *info)
677 return info <= SEND_SIG_FORCED;
680 static inline bool si_fromuser(const struct siginfo *info)
682 return info == SEND_SIG_NOINFO ||
683 (!is_si_special(info) && SI_FROMUSER(info));
687 * Bad permissions for sending the signal
688 * - the caller must hold the RCU read lock
690 static int check_kill_permission(int sig, struct siginfo *info,
691 struct task_struct *t)
693 const struct cred *cred, *tcred;
697 if (!valid_signal(sig))
700 if (!si_fromuser(info))
703 error = audit_signal_info(sig, t); /* Let audit system see the signal */
707 cred = current_cred();
708 tcred = __task_cred(t);
709 if (!same_thread_group(current, t) &&
710 (cred->euid ^ tcred->suid) &&
711 (cred->euid ^ tcred->uid) &&
712 (cred->uid ^ tcred->suid) &&
713 (cred->uid ^ tcred->uid) &&
714 !capable(CAP_KILL)) {
717 sid = task_session(t);
719 * We don't return the error if sid == NULL. The
720 * task was unhashed, the caller must notice this.
722 if (!sid || sid == task_session(current))
729 return security_task_kill(t, info, sig, 0);
733 * Handle magic process-wide effects of stop/continue signals. Unlike
734 * the signal actions, these happen immediately at signal-generation
735 * time regardless of blocking, ignoring, or handling. This does the
736 * actual continuing for SIGCONT, but not the actual stopping for stop
737 * signals. The process stop is done as a signal action for SIG_DFL.
739 * Returns true if the signal should be actually delivered, otherwise
740 * it should be dropped.
742 static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns)
744 struct signal_struct *signal = p->signal;
745 struct task_struct *t;
747 if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) {
749 * The process is in the middle of dying, nothing to do.
751 } else if (sig_kernel_stop(sig)) {
753 * This is a stop signal. Remove SIGCONT from all queues.
755 rm_from_queue(sigmask(SIGCONT), &signal->shared_pending);
758 rm_from_queue(sigmask(SIGCONT), &t->pending);
759 } while_each_thread(p, t);
760 } else if (sig == SIGCONT) {
763 * Remove all stop signals from all queues,
764 * and wake all threads.
766 rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
771 task_clear_group_stop_pending(t);
773 rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
775 * If there is a handler for SIGCONT, we must make
776 * sure that no thread returns to user mode before
777 * we post the signal, in case it was the only
778 * thread eligible to run the signal handler--then
779 * it must not do anything between resuming and
780 * running the handler. With the TIF_SIGPENDING
781 * flag set, the thread will pause and acquire the
782 * siglock that we hold now and until we've queued
783 * the pending signal.
785 * Wake up the stopped thread _after_ setting
788 state = __TASK_STOPPED;
789 if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) {
790 set_tsk_thread_flag(t, TIF_SIGPENDING);
791 state |= TASK_INTERRUPTIBLE;
793 wake_up_state(t, state);
794 } while_each_thread(p, t);
797 * Notify the parent with CLD_CONTINUED if we were stopped.
799 * If we were in the middle of a group stop, we pretend it
800 * was already finished, and then continued. Since SIGCHLD
801 * doesn't queue we report only CLD_STOPPED, as if the next
802 * CLD_CONTINUED was dropped.
805 if (signal->flags & SIGNAL_STOP_STOPPED)
806 why |= SIGNAL_CLD_CONTINUED;
807 else if (signal->group_stop_count)
808 why |= SIGNAL_CLD_STOPPED;
812 * The first thread which returns from do_signal_stop()
813 * will take ->siglock, notice SIGNAL_CLD_MASK, and
814 * notify its parent. See get_signal_to_deliver().
816 signal->flags = why | SIGNAL_STOP_CONTINUED;
817 signal->group_stop_count = 0;
818 signal->group_exit_code = 0;
821 * We are not stopped, but there could be a stop
822 * signal in the middle of being processed after
823 * being removed from the queue. Clear that too.
825 signal->flags &= ~SIGNAL_STOP_DEQUEUED;
829 return !sig_ignored(p, sig, from_ancestor_ns);
833 * Test if P wants to take SIG. After we've checked all threads with this,
834 * it's equivalent to finding no threads not blocking SIG. Any threads not
835 * blocking SIG were ruled out because they are not running and already
836 * have pending signals. Such threads will dequeue from the shared queue
837 * as soon as they're available, so putting the signal on the shared queue
838 * will be equivalent to sending it to one such thread.
840 static inline int wants_signal(int sig, struct task_struct *p)
842 if (sigismember(&p->blocked, sig))
844 if (p->flags & PF_EXITING)
848 if (task_is_stopped_or_traced(p))
850 return task_curr(p) || !signal_pending(p);
853 static void complete_signal(int sig, struct task_struct *p, int group)
855 struct signal_struct *signal = p->signal;
856 struct task_struct *t;
859 * Now find a thread we can wake up to take the signal off the queue.
861 * If the main thread wants the signal, it gets first crack.
862 * Probably the least surprising to the average bear.
864 if (wants_signal(sig, p))
866 else if (!group || thread_group_empty(p))
868 * There is just one thread and it does not need to be woken.
869 * It will dequeue unblocked signals before it runs again.
874 * Otherwise try to find a suitable thread.
876 t = signal->curr_target;
877 while (!wants_signal(sig, t)) {
879 if (t == signal->curr_target)
881 * No thread needs to be woken.
882 * Any eligible threads will see
883 * the signal in the queue soon.
887 signal->curr_target = t;
891 * Found a killable thread. If the signal will be fatal,
892 * then start taking the whole group down immediately.
894 if (sig_fatal(p, sig) &&
895 !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
896 !sigismember(&t->real_blocked, sig) &&
898 !tracehook_consider_fatal_signal(t, sig))) {
900 * This signal will be fatal to the whole group.
902 if (!sig_kernel_coredump(sig)) {
904 * Start a group exit and wake everybody up.
905 * This way we don't have other threads
906 * running and doing things after a slower
907 * thread has the fatal signal pending.
909 signal->flags = SIGNAL_GROUP_EXIT;
910 signal->group_exit_code = sig;
911 signal->group_stop_count = 0;
914 task_clear_group_stop_pending(t);
915 sigaddset(&t->pending.signal, SIGKILL);
916 signal_wake_up(t, 1);
917 } while_each_thread(p, t);
923 * The signal is already in the shared-pending queue.
924 * Tell the chosen thread to wake up and dequeue it.
926 signal_wake_up(t, sig == SIGKILL);
930 static inline int legacy_queue(struct sigpending *signals, int sig)
932 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
935 static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
936 int group, int from_ancestor_ns)
938 struct sigpending *pending;
942 trace_signal_generate(sig, info, t);
944 assert_spin_locked(&t->sighand->siglock);
946 if (!prepare_signal(sig, t, from_ancestor_ns))
949 pending = group ? &t->signal->shared_pending : &t->pending;
951 * Short-circuit ignored signals and support queuing
952 * exactly one non-rt signal, so that we can get more
953 * detailed information about the cause of the signal.
955 if (legacy_queue(pending, sig))
958 * fast-pathed signals for kernel-internal things like SIGSTOP
961 if (info == SEND_SIG_FORCED)
964 /* Real-time signals must be queued if sent by sigqueue, or
965 some other real-time mechanism. It is implementation
966 defined whether kill() does so. We attempt to do so, on
967 the principle of least surprise, but since kill is not
968 allowed to fail with EAGAIN when low on memory we just
969 make sure at least one signal gets delivered and don't
970 pass on the info struct. */
973 override_rlimit = (is_si_special(info) || info->si_code >= 0);
977 q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
980 list_add_tail(&q->list, &pending->list);
981 switch ((unsigned long) info) {
982 case (unsigned long) SEND_SIG_NOINFO:
983 q->info.si_signo = sig;
984 q->info.si_errno = 0;
985 q->info.si_code = SI_USER;
986 q->info.si_pid = task_tgid_nr_ns(current,
987 task_active_pid_ns(t));
988 q->info.si_uid = current_uid();
990 case (unsigned long) SEND_SIG_PRIV:
991 q->info.si_signo = sig;
992 q->info.si_errno = 0;
993 q->info.si_code = SI_KERNEL;
998 copy_siginfo(&q->info, info);
999 if (from_ancestor_ns)
1003 } else if (!is_si_special(info)) {
1004 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
1006 * Queue overflow, abort. We may abort if the
1007 * signal was rt and sent by user using something
1008 * other than kill().
1010 trace_signal_overflow_fail(sig, group, info);
1014 * This is a silent loss of information. We still
1015 * send the signal, but the *info bits are lost.
1017 trace_signal_lose_info(sig, group, info);
1022 signalfd_notify(t, sig);
1023 sigaddset(&pending->signal, sig);
1024 complete_signal(sig, t, group);
1028 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
1031 int from_ancestor_ns = 0;
1033 #ifdef CONFIG_PID_NS
1034 from_ancestor_ns = si_fromuser(info) &&
1035 !task_pid_nr_ns(current, task_active_pid_ns(t));
1038 return __send_signal(sig, info, t, group, from_ancestor_ns);
1041 static void print_fatal_signal(struct pt_regs *regs, int signr)
1043 printk("%s/%d: potentially unexpected fatal signal %d.\n",
1044 current->comm, task_pid_nr(current), signr);
1046 #if defined(__i386__) && !defined(__arch_um__)
1047 printk("code at %08lx: ", regs->ip);
1050 for (i = 0; i < 16; i++) {
1053 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1055 printk("%02x ", insn);
1065 static int __init setup_print_fatal_signals(char *str)
1067 get_option (&str, &print_fatal_signals);
1072 __setup("print-fatal-signals=", setup_print_fatal_signals);
1075 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1077 return send_signal(sig, info, p, 1);
1081 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1083 return send_signal(sig, info, t, 0);
1086 int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
1089 unsigned long flags;
1092 if (lock_task_sighand(p, &flags)) {
1093 ret = send_signal(sig, info, p, group);
1094 unlock_task_sighand(p, &flags);
1101 * Force a signal that the process can't ignore: if necessary
1102 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1104 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1105 * since we do not want to have a signal handler that was blocked
1106 * be invoked when user space had explicitly blocked it.
1108 * We don't want to have recursive SIGSEGV's etc, for example,
1109 * that is why we also clear SIGNAL_UNKILLABLE.
1112 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1114 unsigned long int flags;
1115 int ret, blocked, ignored;
1116 struct k_sigaction *action;
1118 spin_lock_irqsave(&t->sighand->siglock, flags);
1119 action = &t->sighand->action[sig-1];
1120 ignored = action->sa.sa_handler == SIG_IGN;
1121 blocked = sigismember(&t->blocked, sig);
1122 if (blocked || ignored) {
1123 action->sa.sa_handler = SIG_DFL;
1125 sigdelset(&t->blocked, sig);
1126 recalc_sigpending_and_wake(t);
1129 if (action->sa.sa_handler == SIG_DFL)
1130 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1131 ret = specific_send_sig_info(sig, info, t);
1132 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1138 * Nuke all other threads in the group.
1140 int zap_other_threads(struct task_struct *p)
1142 struct task_struct *t = p;
1145 p->signal->group_stop_count = 0;
1147 while_each_thread(p, t) {
1148 task_clear_group_stop_pending(t);
1151 /* Don't bother with already dead threads */
1154 sigaddset(&t->pending.signal, SIGKILL);
1155 signal_wake_up(t, 1);
1161 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1162 unsigned long *flags)
1164 struct sighand_struct *sighand;
1168 sighand = rcu_dereference(tsk->sighand);
1169 if (unlikely(sighand == NULL))
1172 spin_lock_irqsave(&sighand->siglock, *flags);
1173 if (likely(sighand == tsk->sighand))
1175 spin_unlock_irqrestore(&sighand->siglock, *flags);
1183 * send signal info to all the members of a group
1185 int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1190 ret = check_kill_permission(sig, info, p);
1194 ret = do_send_sig_info(sig, info, p, true);
1200 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1201 * control characters do (^C, ^Z etc)
1202 * - the caller must hold at least a readlock on tasklist_lock
1204 int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
1206 struct task_struct *p = NULL;
1207 int retval, success;
1211 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1212 int err = group_send_sig_info(sig, info, p);
1215 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1216 return success ? 0 : retval;
1219 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
1222 struct task_struct *p;
1226 p = pid_task(pid, PIDTYPE_PID);
1228 error = group_send_sig_info(sig, info, p);
1229 if (unlikely(error == -ESRCH))
1231 * The task was unhashed in between, try again.
1232 * If it is dead, pid_task() will return NULL,
1233 * if we race with de_thread() it will find the
1244 kill_proc_info(int sig, struct siginfo *info, pid_t pid)
1248 error = kill_pid_info(sig, info, find_vpid(pid));
1253 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1254 int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
1255 uid_t uid, uid_t euid, u32 secid)
1258 struct task_struct *p;
1259 const struct cred *pcred;
1260 unsigned long flags;
1262 if (!valid_signal(sig))
1266 p = pid_task(pid, PIDTYPE_PID);
1271 pcred = __task_cred(p);
1272 if (si_fromuser(info) &&
1273 euid != pcred->suid && euid != pcred->uid &&
1274 uid != pcred->suid && uid != pcred->uid) {
1278 ret = security_task_kill(p, info, sig, secid);
1283 if (lock_task_sighand(p, &flags)) {
1284 ret = __send_signal(sig, info, p, 1, 0);
1285 unlock_task_sighand(p, &flags);
1293 EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
1296 * kill_something_info() interprets pid in interesting ways just like kill(2).
1298 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1299 * is probably wrong. Should make it like BSD or SYSV.
1302 static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
1308 ret = kill_pid_info(sig, info, find_vpid(pid));
1313 read_lock(&tasklist_lock);
1315 ret = __kill_pgrp_info(sig, info,
1316 pid ? find_vpid(-pid) : task_pgrp(current));
1318 int retval = 0, count = 0;
1319 struct task_struct * p;
1321 for_each_process(p) {
1322 if (task_pid_vnr(p) > 1 &&
1323 !same_thread_group(p, current)) {
1324 int err = group_send_sig_info(sig, info, p);
1330 ret = count ? retval : -ESRCH;
1332 read_unlock(&tasklist_lock);
1338 * These are for backward compatibility with the rest of the kernel source.
1342 send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1345 * Make sure legacy kernel users don't send in bad values
1346 * (normal paths check this in check_kill_permission).
1348 if (!valid_signal(sig))
1351 return do_send_sig_info(sig, info, p, false);
1354 #define __si_special(priv) \
1355 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1358 send_sig(int sig, struct task_struct *p, int priv)
1360 return send_sig_info(sig, __si_special(priv), p);
1364 force_sig(int sig, struct task_struct *p)
1366 force_sig_info(sig, SEND_SIG_PRIV, p);
1370 * When things go south during signal handling, we
1371 * will force a SIGSEGV. And if the signal that caused
1372 * the problem was already a SIGSEGV, we'll want to
1373 * make sure we don't even try to deliver the signal..
1376 force_sigsegv(int sig, struct task_struct *p)
1378 if (sig == SIGSEGV) {
1379 unsigned long flags;
1380 spin_lock_irqsave(&p->sighand->siglock, flags);
1381 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1382 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1384 force_sig(SIGSEGV, p);
1388 int kill_pgrp(struct pid *pid, int sig, int priv)
1392 read_lock(&tasklist_lock);
1393 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1394 read_unlock(&tasklist_lock);
1398 EXPORT_SYMBOL(kill_pgrp);
1400 int kill_pid(struct pid *pid, int sig, int priv)
1402 return kill_pid_info(sig, __si_special(priv), pid);
1404 EXPORT_SYMBOL(kill_pid);
1407 * These functions support sending signals using preallocated sigqueue
1408 * structures. This is needed "because realtime applications cannot
1409 * afford to lose notifications of asynchronous events, like timer
1410 * expirations or I/O completions". In the case of Posix Timers
1411 * we allocate the sigqueue structure from the timer_create. If this
1412 * allocation fails we are able to report the failure to the application
1413 * with an EAGAIN error.
1415 struct sigqueue *sigqueue_alloc(void)
1417 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1420 q->flags |= SIGQUEUE_PREALLOC;
1425 void sigqueue_free(struct sigqueue *q)
1427 unsigned long flags;
1428 spinlock_t *lock = ¤t->sighand->siglock;
1430 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1432 * We must hold ->siglock while testing q->list
1433 * to serialize with collect_signal() or with
1434 * __exit_signal()->flush_sigqueue().
1436 spin_lock_irqsave(lock, flags);
1437 q->flags &= ~SIGQUEUE_PREALLOC;
1439 * If it is queued it will be freed when dequeued,
1440 * like the "regular" sigqueue.
1442 if (!list_empty(&q->list))
1444 spin_unlock_irqrestore(lock, flags);
1450 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1452 int sig = q->info.si_signo;
1453 struct sigpending *pending;
1454 unsigned long flags;
1457 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1460 if (!likely(lock_task_sighand(t, &flags)))
1463 ret = 1; /* the signal is ignored */
1464 if (!prepare_signal(sig, t, 0))
1468 if (unlikely(!list_empty(&q->list))) {
1470 * If an SI_TIMER entry is already queue just increment
1471 * the overrun count.
1473 BUG_ON(q->info.si_code != SI_TIMER);
1474 q->info.si_overrun++;
1477 q->info.si_overrun = 0;
1479 signalfd_notify(t, sig);
1480 pending = group ? &t->signal->shared_pending : &t->pending;
1481 list_add_tail(&q->list, &pending->list);
1482 sigaddset(&pending->signal, sig);
1483 complete_signal(sig, t, group);
1485 unlock_task_sighand(t, &flags);
1491 * Let a parent know about the death of a child.
1492 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1494 * Returns -1 if our parent ignored us and so we've switched to
1495 * self-reaping, or else @sig.
1497 int do_notify_parent(struct task_struct *tsk, int sig)
1499 struct siginfo info;
1500 unsigned long flags;
1501 struct sighand_struct *psig;
1506 /* do_notify_parent_cldstop should have been called instead. */
1507 BUG_ON(task_is_stopped_or_traced(tsk));
1509 BUG_ON(!task_ptrace(tsk) &&
1510 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1512 info.si_signo = sig;
1515 * we are under tasklist_lock here so our parent is tied to
1516 * us and cannot exit and release its namespace.
1518 * the only it can is to switch its nsproxy with sys_unshare,
1519 * bu uncharing pid namespaces is not allowed, so we'll always
1520 * see relevant namespace
1522 * write_lock() currently calls preempt_disable() which is the
1523 * same as rcu_read_lock(), but according to Oleg, this is not
1524 * correct to rely on this
1527 info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
1528 info.si_uid = __task_cred(tsk)->uid;
1531 info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime,
1532 tsk->signal->utime));
1533 info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime,
1534 tsk->signal->stime));
1536 info.si_status = tsk->exit_code & 0x7f;
1537 if (tsk->exit_code & 0x80)
1538 info.si_code = CLD_DUMPED;
1539 else if (tsk->exit_code & 0x7f)
1540 info.si_code = CLD_KILLED;
1542 info.si_code = CLD_EXITED;
1543 info.si_status = tsk->exit_code >> 8;
1546 psig = tsk->parent->sighand;
1547 spin_lock_irqsave(&psig->siglock, flags);
1548 if (!task_ptrace(tsk) && sig == SIGCHLD &&
1549 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1550 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1552 * We are exiting and our parent doesn't care. POSIX.1
1553 * defines special semantics for setting SIGCHLD to SIG_IGN
1554 * or setting the SA_NOCLDWAIT flag: we should be reaped
1555 * automatically and not left for our parent's wait4 call.
1556 * Rather than having the parent do it as a magic kind of
1557 * signal handler, we just set this to tell do_exit that we
1558 * can be cleaned up without becoming a zombie. Note that
1559 * we still call __wake_up_parent in this case, because a
1560 * blocked sys_wait4 might now return -ECHILD.
1562 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1563 * is implementation-defined: we do (if you don't want
1564 * it, just use SIG_IGN instead).
1566 ret = tsk->exit_signal = -1;
1567 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1570 if (valid_signal(sig) && sig > 0)
1571 __group_send_sig_info(sig, &info, tsk->parent);
1572 __wake_up_parent(tsk, tsk->parent);
1573 spin_unlock_irqrestore(&psig->siglock, flags);
1578 static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
1580 struct siginfo info;
1581 unsigned long flags;
1582 struct task_struct *parent;
1583 struct sighand_struct *sighand;
1585 if (task_ptrace(tsk))
1586 parent = tsk->parent;
1588 tsk = tsk->group_leader;
1589 parent = tsk->real_parent;
1592 info.si_signo = SIGCHLD;
1595 * see comment in do_notify_parent() abot the following 3 lines
1598 info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
1599 info.si_uid = __task_cred(tsk)->uid;
1602 info.si_utime = cputime_to_clock_t(tsk->utime);
1603 info.si_stime = cputime_to_clock_t(tsk->stime);
1608 info.si_status = SIGCONT;
1611 info.si_status = tsk->signal->group_exit_code & 0x7f;
1614 info.si_status = tsk->exit_code & 0x7f;
1620 sighand = parent->sighand;
1621 spin_lock_irqsave(&sighand->siglock, flags);
1622 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1623 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1624 __group_send_sig_info(SIGCHLD, &info, parent);
1626 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1628 __wake_up_parent(tsk, parent);
1629 spin_unlock_irqrestore(&sighand->siglock, flags);
1632 static inline int may_ptrace_stop(void)
1634 if (!likely(task_ptrace(current)))
1637 * Are we in the middle of do_coredump?
1638 * If so and our tracer is also part of the coredump stopping
1639 * is a deadlock situation, and pointless because our tracer
1640 * is dead so don't allow us to stop.
1641 * If SIGKILL was already sent before the caller unlocked
1642 * ->siglock we must see ->core_state != NULL. Otherwise it
1643 * is safe to enter schedule().
1645 if (unlikely(current->mm->core_state) &&
1646 unlikely(current->mm == current->parent->mm))
1653 * Return nonzero if there is a SIGKILL that should be waking us up.
1654 * Called with the siglock held.
1656 static int sigkill_pending(struct task_struct *tsk)
1658 return sigismember(&tsk->pending.signal, SIGKILL) ||
1659 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
1663 * This must be called with current->sighand->siglock held.
1665 * This should be the path for all ptrace stops.
1666 * We always set current->last_siginfo while stopped here.
1667 * That makes it a way to test a stopped process for
1668 * being ptrace-stopped vs being job-control-stopped.
1670 * If we actually decide not to stop at all because the tracer
1671 * is gone, we keep current->exit_code unless clear_code.
1673 static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
1674 __releases(¤t->sighand->siglock)
1675 __acquires(¤t->sighand->siglock)
1677 if (arch_ptrace_stop_needed(exit_code, info)) {
1679 * The arch code has something special to do before a
1680 * ptrace stop. This is allowed to block, e.g. for faults
1681 * on user stack pages. We can't keep the siglock while
1682 * calling arch_ptrace_stop, so we must release it now.
1683 * To preserve proper semantics, we must do this before
1684 * any signal bookkeeping like checking group_stop_count.
1685 * Meanwhile, a SIGKILL could come in before we retake the
1686 * siglock. That must prevent us from sleeping in TASK_TRACED.
1687 * So after regaining the lock, we must check for SIGKILL.
1689 spin_unlock_irq(¤t->sighand->siglock);
1690 arch_ptrace_stop(exit_code, info);
1691 spin_lock_irq(¤t->sighand->siglock);
1692 if (sigkill_pending(current))
1697 * If there is a group stop in progress,
1698 * we must participate in the bookkeeping.
1700 if (current->group_stop & GROUP_STOP_PENDING)
1701 task_participate_group_stop(current);
1703 current->last_siginfo = info;
1704 current->exit_code = exit_code;
1706 /* Let the debugger run. */
1707 __set_current_state(TASK_TRACED);
1708 spin_unlock_irq(¤t->sighand->siglock);
1709 read_lock(&tasklist_lock);
1710 if (may_ptrace_stop()) {
1711 do_notify_parent_cldstop(current, why);
1713 * Don't want to allow preemption here, because
1714 * sys_ptrace() needs this task to be inactive.
1716 * XXX: implement read_unlock_no_resched().
1719 read_unlock(&tasklist_lock);
1720 preempt_enable_no_resched();
1724 * By the time we got the lock, our tracer went away.
1725 * Don't drop the lock yet, another tracer may come.
1727 __set_current_state(TASK_RUNNING);
1729 current->exit_code = 0;
1730 read_unlock(&tasklist_lock);
1734 * While in TASK_TRACED, we were considered "frozen enough".
1735 * Now that we woke up, it's crucial if we're supposed to be
1736 * frozen that we freeze now before running anything substantial.
1741 * We are back. Now reacquire the siglock before touching
1742 * last_siginfo, so that we are sure to have synchronized with
1743 * any signal-sending on another CPU that wants to examine it.
1745 spin_lock_irq(¤t->sighand->siglock);
1746 current->last_siginfo = NULL;
1749 * Queued signals ignored us while we were stopped for tracing.
1750 * So check for any that we should take before resuming user mode.
1751 * This sets TIF_SIGPENDING, but never clears it.
1753 recalc_sigpending_tsk(current);
1756 void ptrace_notify(int exit_code)
1760 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1762 memset(&info, 0, sizeof info);
1763 info.si_signo = SIGTRAP;
1764 info.si_code = exit_code;
1765 info.si_pid = task_pid_vnr(current);
1766 info.si_uid = current_uid();
1768 /* Let the debugger run. */
1769 spin_lock_irq(¤t->sighand->siglock);
1770 ptrace_stop(exit_code, CLD_TRAPPED, 1, &info);
1771 spin_unlock_irq(¤t->sighand->siglock);
1775 * This performs the stopping for SIGSTOP and other stop signals.
1776 * We have to stop all threads in the thread group.
1777 * Returns nonzero if we've actually stopped and released the siglock.
1778 * Returns zero if we didn't stop and still hold the siglock.
1780 static int do_signal_stop(int signr)
1782 struct signal_struct *sig = current->signal;
1785 if (!(current->group_stop & GROUP_STOP_PENDING)) {
1786 unsigned int gstop = GROUP_STOP_PENDING | GROUP_STOP_CONSUME;
1787 struct task_struct *t;
1789 if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
1790 unlikely(signal_group_exit(sig)))
1793 * There is no group stop already in progress.
1794 * We must initiate one now.
1796 sig->group_exit_code = signr;
1798 current->group_stop = gstop;
1799 sig->group_stop_count = 1;
1800 for (t = next_thread(current); t != current; t = next_thread(t))
1802 * Setting state to TASK_STOPPED for a group
1803 * stop is always done with the siglock held,
1804 * so this check has no races.
1806 if (!(t->flags & PF_EXITING) && !task_is_stopped(t)) {
1807 t->group_stop = gstop;
1808 sig->group_stop_count++;
1809 signal_wake_up(t, 0);
1811 task_clear_group_stop_pending(t);
1814 * If there are no other threads in the group, or if there is
1815 * a group stop in progress and we are the last to stop, report
1816 * to the parent. When ptraced, every thread reports itself.
1818 if (task_participate_group_stop(current))
1819 notify = CLD_STOPPED;
1820 if (task_ptrace(current))
1821 notify = CLD_STOPPED;
1823 current->exit_code = sig->group_exit_code;
1824 __set_current_state(TASK_STOPPED);
1826 spin_unlock_irq(¤t->sighand->siglock);
1829 read_lock(&tasklist_lock);
1830 do_notify_parent_cldstop(current, notify);
1831 read_unlock(&tasklist_lock);
1834 /* Now we don't run again until woken by SIGCONT or SIGKILL */
1837 tracehook_finish_jctl();
1838 current->exit_code = 0;
1843 static int ptrace_signal(int signr, siginfo_t *info,
1844 struct pt_regs *regs, void *cookie)
1846 if (!task_ptrace(current))
1849 ptrace_signal_deliver(regs, cookie);
1851 /* Let the debugger run. */
1852 ptrace_stop(signr, CLD_TRAPPED, 0, info);
1854 /* We're back. Did the debugger cancel the sig? */
1855 signr = current->exit_code;
1859 current->exit_code = 0;
1861 /* Update the siginfo structure if the signal has
1862 changed. If the debugger wanted something
1863 specific in the siginfo structure then it should
1864 have updated *info via PTRACE_SETSIGINFO. */
1865 if (signr != info->si_signo) {
1866 info->si_signo = signr;
1868 info->si_code = SI_USER;
1869 info->si_pid = task_pid_vnr(current->parent);
1870 info->si_uid = task_uid(current->parent);
1873 /* If the (new) signal is now blocked, requeue it. */
1874 if (sigismember(¤t->blocked, signr)) {
1875 specific_send_sig_info(signr, info, current);
1882 int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
1883 struct pt_regs *regs, void *cookie)
1885 struct sighand_struct *sighand = current->sighand;
1886 struct signal_struct *signal = current->signal;
1891 * We'll jump back here after any time we were stopped in TASK_STOPPED.
1892 * While in TASK_STOPPED, we were considered "frozen enough".
1893 * Now that we woke up, it's crucial if we're supposed to be
1894 * frozen that we freeze now before running anything substantial.
1898 spin_lock_irq(&sighand->siglock);
1900 * Every stopped thread goes here after wakeup. Check to see if
1901 * we should notify the parent, prepare_signal(SIGCONT) encodes
1902 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
1904 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
1907 if (signal->flags & SIGNAL_CLD_CONTINUED)
1908 why = CLD_CONTINUED;
1912 signal->flags &= ~SIGNAL_CLD_MASK;
1914 spin_unlock_irq(&sighand->siglock);
1916 read_lock(&tasklist_lock);
1917 do_notify_parent_cldstop(current->group_leader, why);
1918 read_unlock(&tasklist_lock);
1923 struct k_sigaction *ka;
1925 * Tracing can induce an artifical signal and choose sigaction.
1926 * The return value in @signr determines the default action,
1927 * but @info->si_signo is the signal number we will report.
1929 signr = tracehook_get_signal(current, regs, info, return_ka);
1930 if (unlikely(signr < 0))
1932 if (unlikely(signr != 0))
1935 if (unlikely(current->group_stop &
1936 GROUP_STOP_PENDING) && do_signal_stop(0))
1939 signr = dequeue_signal(current, ¤t->blocked,
1943 break; /* will return 0 */
1945 if (signr != SIGKILL) {
1946 signr = ptrace_signal(signr, info,
1952 ka = &sighand->action[signr-1];
1955 /* Trace actually delivered signals. */
1956 trace_signal_deliver(signr, info, ka);
1958 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
1960 if (ka->sa.sa_handler != SIG_DFL) {
1961 /* Run the handler. */
1964 if (ka->sa.sa_flags & SA_ONESHOT)
1965 ka->sa.sa_handler = SIG_DFL;
1967 break; /* will return non-zero "signr" value */
1971 * Now we are doing the default action for this signal.
1973 if (sig_kernel_ignore(signr)) /* Default is nothing. */
1977 * Global init gets no signals it doesn't want.
1978 * Container-init gets no signals it doesn't want from same
1981 * Note that if global/container-init sees a sig_kernel_only()
1982 * signal here, the signal must have been generated internally
1983 * or must have come from an ancestor namespace. In either
1984 * case, the signal cannot be dropped.
1986 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
1987 !sig_kernel_only(signr))
1990 if (sig_kernel_stop(signr)) {
1992 * The default action is to stop all threads in
1993 * the thread group. The job control signals
1994 * do nothing in an orphaned pgrp, but SIGSTOP
1995 * always works. Note that siglock needs to be
1996 * dropped during the call to is_orphaned_pgrp()
1997 * because of lock ordering with tasklist_lock.
1998 * This allows an intervening SIGCONT to be posted.
1999 * We need to check for that and bail out if necessary.
2001 if (signr != SIGSTOP) {
2002 spin_unlock_irq(&sighand->siglock);
2004 /* signals can be posted during this window */
2006 if (is_current_pgrp_orphaned())
2009 spin_lock_irq(&sighand->siglock);
2012 if (likely(do_signal_stop(info->si_signo))) {
2013 /* It released the siglock. */
2018 * We didn't actually stop, due to a race
2019 * with SIGCONT or something like that.
2024 spin_unlock_irq(&sighand->siglock);
2027 * Anything else is fatal, maybe with a core dump.
2029 current->flags |= PF_SIGNALED;
2031 if (sig_kernel_coredump(signr)) {
2032 if (print_fatal_signals)
2033 print_fatal_signal(regs, info->si_signo);
2035 * If it was able to dump core, this kills all
2036 * other threads in the group and synchronizes with
2037 * their demise. If we lost the race with another
2038 * thread getting here, it set group_exit_code
2039 * first and our do_group_exit call below will use
2040 * that value and ignore the one we pass it.
2042 do_coredump(info->si_signo, info->si_signo, regs);
2046 * Death signals, no core dump.
2048 do_group_exit(info->si_signo);
2051 spin_unlock_irq(&sighand->siglock);
2055 void exit_signals(struct task_struct *tsk)
2058 struct task_struct *t;
2060 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2061 tsk->flags |= PF_EXITING;
2065 spin_lock_irq(&tsk->sighand->siglock);
2067 * From now this task is not visible for group-wide signals,
2068 * see wants_signal(), do_signal_stop().
2070 tsk->flags |= PF_EXITING;
2071 if (!signal_pending(tsk))
2074 /* It could be that __group_complete_signal() choose us to
2075 * notify about group-wide signal. Another thread should be
2076 * woken now to take the signal since we will not.
2078 for (t = tsk; (t = next_thread(t)) != tsk; )
2079 if (!signal_pending(t) && !(t->flags & PF_EXITING))
2080 recalc_sigpending_and_wake(t);
2082 if (unlikely(tsk->group_stop & GROUP_STOP_PENDING) &&
2083 task_participate_group_stop(tsk))
2084 group_stop = CLD_STOPPED;
2086 spin_unlock_irq(&tsk->sighand->siglock);
2088 if (unlikely(group_stop)) {
2089 read_lock(&tasklist_lock);
2090 do_notify_parent_cldstop(tsk, group_stop);
2091 read_unlock(&tasklist_lock);
2095 EXPORT_SYMBOL(recalc_sigpending);
2096 EXPORT_SYMBOL_GPL(dequeue_signal);
2097 EXPORT_SYMBOL(flush_signals);
2098 EXPORT_SYMBOL(force_sig);
2099 EXPORT_SYMBOL(send_sig);
2100 EXPORT_SYMBOL(send_sig_info);
2101 EXPORT_SYMBOL(sigprocmask);
2102 EXPORT_SYMBOL(block_all_signals);
2103 EXPORT_SYMBOL(unblock_all_signals);
2107 * System call entry points.
2110 SYSCALL_DEFINE0(restart_syscall)
2112 struct restart_block *restart = ¤t_thread_info()->restart_block;
2113 return restart->fn(restart);
2116 long do_no_restart_syscall(struct restart_block *param)
2122 * We don't need to get the kernel lock - this is all local to this
2123 * particular thread.. (and that's good, because this is _heavily_
2124 * used by various programs)
2128 * This is also useful for kernel threads that want to temporarily
2129 * (or permanently) block certain signals.
2131 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2132 * interface happily blocks "unblockable" signals like SIGKILL
2135 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2139 spin_lock_irq(¤t->sighand->siglock);
2141 *oldset = current->blocked;
2146 sigorsets(¤t->blocked, ¤t->blocked, set);
2149 signandsets(¤t->blocked, ¤t->blocked, set);
2152 current->blocked = *set;
2157 recalc_sigpending();
2158 spin_unlock_irq(¤t->sighand->siglock);
2163 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set,
2164 sigset_t __user *, oset, size_t, sigsetsize)
2166 int error = -EINVAL;
2167 sigset_t old_set, new_set;
2169 /* XXX: Don't preclude handling different sized sigset_t's. */
2170 if (sigsetsize != sizeof(sigset_t))
2175 if (copy_from_user(&new_set, set, sizeof(*set)))
2177 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2179 error = sigprocmask(how, &new_set, &old_set);
2185 spin_lock_irq(¤t->sighand->siglock);
2186 old_set = current->blocked;
2187 spin_unlock_irq(¤t->sighand->siglock);
2191 if (copy_to_user(oset, &old_set, sizeof(*oset)))
2199 long do_sigpending(void __user *set, unsigned long sigsetsize)
2201 long error = -EINVAL;
2204 if (sigsetsize > sizeof(sigset_t))
2207 spin_lock_irq(¤t->sighand->siglock);
2208 sigorsets(&pending, ¤t->pending.signal,
2209 ¤t->signal->shared_pending.signal);
2210 spin_unlock_irq(¤t->sighand->siglock);
2212 /* Outside the lock because only this thread touches it. */
2213 sigandsets(&pending, ¤t->blocked, &pending);
2216 if (!copy_to_user(set, &pending, sigsetsize))
2223 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize)
2225 return do_sigpending(set, sigsetsize);
2228 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2230 int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
2234 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2236 if (from->si_code < 0)
2237 return __copy_to_user(to, from, sizeof(siginfo_t))
2240 * If you change siginfo_t structure, please be sure
2241 * this code is fixed accordingly.
2242 * Please remember to update the signalfd_copyinfo() function
2243 * inside fs/signalfd.c too, in case siginfo_t changes.
2244 * It should never copy any pad contained in the structure
2245 * to avoid security leaks, but must copy the generic
2246 * 3 ints plus the relevant union member.
2248 err = __put_user(from->si_signo, &to->si_signo);
2249 err |= __put_user(from->si_errno, &to->si_errno);
2250 err |= __put_user((short)from->si_code, &to->si_code);
2251 switch (from->si_code & __SI_MASK) {
2253 err |= __put_user(from->si_pid, &to->si_pid);
2254 err |= __put_user(from->si_uid, &to->si_uid);
2257 err |= __put_user(from->si_tid, &to->si_tid);
2258 err |= __put_user(from->si_overrun, &to->si_overrun);
2259 err |= __put_user(from->si_ptr, &to->si_ptr);
2262 err |= __put_user(from->si_band, &to->si_band);
2263 err |= __put_user(from->si_fd, &to->si_fd);
2266 err |= __put_user(from->si_addr, &to->si_addr);
2267 #ifdef __ARCH_SI_TRAPNO
2268 err |= __put_user(from->si_trapno, &to->si_trapno);
2270 #ifdef BUS_MCEERR_AO
2272 * Other callers might not initialize the si_lsb field,
2273 * so check explicitely for the right codes here.
2275 if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
2276 err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
2280 err |= __put_user(from->si_pid, &to->si_pid);
2281 err |= __put_user(from->si_uid, &to->si_uid);
2282 err |= __put_user(from->si_status, &to->si_status);
2283 err |= __put_user(from->si_utime, &to->si_utime);
2284 err |= __put_user(from->si_stime, &to->si_stime);
2286 case __SI_RT: /* This is not generated by the kernel as of now. */
2287 case __SI_MESGQ: /* But this is */
2288 err |= __put_user(from->si_pid, &to->si_pid);
2289 err |= __put_user(from->si_uid, &to->si_uid);
2290 err |= __put_user(from->si_ptr, &to->si_ptr);
2292 default: /* this is just in case for now ... */
2293 err |= __put_user(from->si_pid, &to->si_pid);
2294 err |= __put_user(from->si_uid, &to->si_uid);
2302 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
2303 siginfo_t __user *, uinfo, const struct timespec __user *, uts,
2312 /* XXX: Don't preclude handling different sized sigset_t's. */
2313 if (sigsetsize != sizeof(sigset_t))
2316 if (copy_from_user(&these, uthese, sizeof(these)))
2320 * Invert the set of allowed signals to get those we
2323 sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP));
2327 if (copy_from_user(&ts, uts, sizeof(ts)))
2329 if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0
2334 spin_lock_irq(¤t->sighand->siglock);
2335 sig = dequeue_signal(current, &these, &info);
2337 timeout = MAX_SCHEDULE_TIMEOUT;
2339 timeout = (timespec_to_jiffies(&ts)
2340 + (ts.tv_sec || ts.tv_nsec));
2343 /* None ready -- temporarily unblock those we're
2344 * interested while we are sleeping in so that we'll
2345 * be awakened when they arrive. */
2346 current->real_blocked = current->blocked;
2347 sigandsets(¤t->blocked, ¤t->blocked, &these);
2348 recalc_sigpending();
2349 spin_unlock_irq(¤t->sighand->siglock);
2351 timeout = schedule_timeout_interruptible(timeout);
2353 spin_lock_irq(¤t->sighand->siglock);
2354 sig = dequeue_signal(current, &these, &info);
2355 current->blocked = current->real_blocked;
2356 siginitset(¤t->real_blocked, 0);
2357 recalc_sigpending();
2360 spin_unlock_irq(¤t->sighand->siglock);
2365 if (copy_siginfo_to_user(uinfo, &info))
2377 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
2379 struct siginfo info;
2381 info.si_signo = sig;
2383 info.si_code = SI_USER;
2384 info.si_pid = task_tgid_vnr(current);
2385 info.si_uid = current_uid();
2387 return kill_something_info(sig, &info, pid);
2391 do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
2393 struct task_struct *p;
2397 p = find_task_by_vpid(pid);
2398 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2399 error = check_kill_permission(sig, info, p);
2401 * The null signal is a permissions and process existence
2402 * probe. No signal is actually delivered.
2404 if (!error && sig) {
2405 error = do_send_sig_info(sig, info, p, false);
2407 * If lock_task_sighand() failed we pretend the task
2408 * dies after receiving the signal. The window is tiny,
2409 * and the signal is private anyway.
2411 if (unlikely(error == -ESRCH))
2420 static int do_tkill(pid_t tgid, pid_t pid, int sig)
2422 struct siginfo info;
2424 info.si_signo = sig;
2426 info.si_code = SI_TKILL;
2427 info.si_pid = task_tgid_vnr(current);
2428 info.si_uid = current_uid();
2430 return do_send_specific(tgid, pid, sig, &info);
2434 * sys_tgkill - send signal to one specific thread
2435 * @tgid: the thread group ID of the thread
2436 * @pid: the PID of the thread
2437 * @sig: signal to be sent
2439 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2440 * exists but it's not belonging to the target process anymore. This
2441 * method solves the problem of threads exiting and PIDs getting reused.
2443 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
2445 /* This is only valid for single tasks */
2446 if (pid <= 0 || tgid <= 0)
2449 return do_tkill(tgid, pid, sig);
2453 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2455 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
2457 /* This is only valid for single tasks */
2461 return do_tkill(0, pid, sig);
2464 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
2465 siginfo_t __user *, uinfo)
2469 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2472 /* Not even root can pretend to send signals from the kernel.
2473 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2475 if (info.si_code != SI_QUEUE) {
2476 /* We used to allow any < 0 si_code */
2477 WARN_ON_ONCE(info.si_code < 0);
2480 info.si_signo = sig;
2482 /* POSIX.1b doesn't mention process groups. */
2483 return kill_proc_info(sig, &info, pid);
2486 long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
2488 /* This is only valid for single tasks */
2489 if (pid <= 0 || tgid <= 0)
2492 /* Not even root can pretend to send signals from the kernel.
2493 * Nor can they impersonate a kill()/tgkill(), which adds source info.
2495 if (info->si_code != SI_QUEUE) {
2496 /* We used to allow any < 0 si_code */
2497 WARN_ON_ONCE(info->si_code < 0);
2500 info->si_signo = sig;
2502 return do_send_specific(tgid, pid, sig, info);
2505 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
2506 siginfo_t __user *, uinfo)
2510 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2513 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
2516 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
2518 struct task_struct *t = current;
2519 struct k_sigaction *k;
2522 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
2525 k = &t->sighand->action[sig-1];
2527 spin_lock_irq(¤t->sighand->siglock);
2532 sigdelsetmask(&act->sa.sa_mask,
2533 sigmask(SIGKILL) | sigmask(SIGSTOP));
2537 * "Setting a signal action to SIG_IGN for a signal that is
2538 * pending shall cause the pending signal to be discarded,
2539 * whether or not it is blocked."
2541 * "Setting a signal action to SIG_DFL for a signal that is
2542 * pending and whose default action is to ignore the signal
2543 * (for example, SIGCHLD), shall cause the pending signal to
2544 * be discarded, whether or not it is blocked"
2546 if (sig_handler_ignored(sig_handler(t, sig), sig)) {
2548 sigaddset(&mask, sig);
2549 rm_from_queue_full(&mask, &t->signal->shared_pending);
2551 rm_from_queue_full(&mask, &t->pending);
2553 } while (t != current);
2557 spin_unlock_irq(¤t->sighand->siglock);
2562 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
2567 oss.ss_sp = (void __user *) current->sas_ss_sp;
2568 oss.ss_size = current->sas_ss_size;
2569 oss.ss_flags = sas_ss_flags(sp);
2577 if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
2579 error = __get_user(ss_sp, &uss->ss_sp) |
2580 __get_user(ss_flags, &uss->ss_flags) |
2581 __get_user(ss_size, &uss->ss_size);
2586 if (on_sig_stack(sp))
2592 * Note - this code used to test ss_flags incorrectly
2593 * old code may have been written using ss_flags==0
2594 * to mean ss_flags==SS_ONSTACK (as this was the only
2595 * way that worked) - this fix preserves that older
2598 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
2601 if (ss_flags == SS_DISABLE) {
2606 if (ss_size < MINSIGSTKSZ)
2610 current->sas_ss_sp = (unsigned long) ss_sp;
2611 current->sas_ss_size = ss_size;
2617 if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
2619 error = __put_user(oss.ss_sp, &uoss->ss_sp) |
2620 __put_user(oss.ss_size, &uoss->ss_size) |
2621 __put_user(oss.ss_flags, &uoss->ss_flags);
2628 #ifdef __ARCH_WANT_SYS_SIGPENDING
2630 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
2632 return do_sigpending(set, sizeof(*set));
2637 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
2638 /* Some platforms have their own version with special arguments others
2639 support only sys_rt_sigprocmask. */
2641 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set,
2642 old_sigset_t __user *, oset)
2645 old_sigset_t old_set, new_set;
2649 if (copy_from_user(&new_set, set, sizeof(*set)))
2651 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
2653 spin_lock_irq(¤t->sighand->siglock);
2654 old_set = current->blocked.sig[0];
2662 sigaddsetmask(¤t->blocked, new_set);
2665 sigdelsetmask(¤t->blocked, new_set);
2668 current->blocked.sig[0] = new_set;
2672 recalc_sigpending();
2673 spin_unlock_irq(¤t->sighand->siglock);
2679 old_set = current->blocked.sig[0];
2682 if (copy_to_user(oset, &old_set, sizeof(*oset)))
2689 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
2691 #ifdef __ARCH_WANT_SYS_RT_SIGACTION
2692 SYSCALL_DEFINE4(rt_sigaction, int, sig,
2693 const struct sigaction __user *, act,
2694 struct sigaction __user *, oact,
2697 struct k_sigaction new_sa, old_sa;
2700 /* XXX: Don't preclude handling different sized sigset_t's. */
2701 if (sigsetsize != sizeof(sigset_t))
2705 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
2709 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
2712 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
2718 #endif /* __ARCH_WANT_SYS_RT_SIGACTION */
2720 #ifdef __ARCH_WANT_SYS_SGETMASK
2723 * For backwards compatibility. Functionality superseded by sigprocmask.
2725 SYSCALL_DEFINE0(sgetmask)
2728 return current->blocked.sig[0];
2731 SYSCALL_DEFINE1(ssetmask, int, newmask)
2735 spin_lock_irq(¤t->sighand->siglock);
2736 old = current->blocked.sig[0];
2738 siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)|
2740 recalc_sigpending();
2741 spin_unlock_irq(¤t->sighand->siglock);
2745 #endif /* __ARCH_WANT_SGETMASK */
2747 #ifdef __ARCH_WANT_SYS_SIGNAL
2749 * For backwards compatibility. Functionality superseded by sigaction.
2751 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
2753 struct k_sigaction new_sa, old_sa;
2756 new_sa.sa.sa_handler = handler;
2757 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
2758 sigemptyset(&new_sa.sa.sa_mask);
2760 ret = do_sigaction(sig, &new_sa, &old_sa);
2762 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
2764 #endif /* __ARCH_WANT_SYS_SIGNAL */
2766 #ifdef __ARCH_WANT_SYS_PAUSE
2768 SYSCALL_DEFINE0(pause)
2770 current->state = TASK_INTERRUPTIBLE;
2772 return -ERESTARTNOHAND;
2777 #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
2778 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
2782 /* XXX: Don't preclude handling different sized sigset_t's. */
2783 if (sigsetsize != sizeof(sigset_t))
2786 if (copy_from_user(&newset, unewset, sizeof(newset)))
2788 sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));
2790 spin_lock_irq(¤t->sighand->siglock);
2791 current->saved_sigmask = current->blocked;
2792 current->blocked = newset;
2793 recalc_sigpending();
2794 spin_unlock_irq(¤t->sighand->siglock);
2796 current->state = TASK_INTERRUPTIBLE;
2798 set_restore_sigmask();
2799 return -ERESTARTNOHAND;
2801 #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */
2803 __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma)
2808 void __init signals_init(void)
2810 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
2813 #ifdef CONFIG_KGDB_KDB
2814 #include <linux/kdb.h>
2816 * kdb_send_sig_info - Allows kdb to send signals without exposing
2817 * signal internals. This function checks if the required locks are
2818 * available before calling the main signal code, to avoid kdb
2822 kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
2824 static struct task_struct *kdb_prev_t;
2826 if (!spin_trylock(&t->sighand->siglock)) {
2827 kdb_printf("Can't do kill command now.\n"
2828 "The sigmask lock is held somewhere else in "
2829 "kernel, try again later\n");
2832 spin_unlock(&t->sighand->siglock);
2833 new_t = kdb_prev_t != t;
2835 if (t->state != TASK_RUNNING && new_t) {
2836 kdb_printf("Process is not RUNNING, sending a signal from "
2837 "kdb risks deadlock\n"
2838 "on the run queue locks. "
2839 "The signal has _not_ been sent.\n"
2840 "Reissue the kill command if you want to risk "
2844 sig = info->si_signo;
2845 if (send_sig_info(sig, info, t))
2846 kdb_printf("Fail to deliver Signal %d to process %d.\n",
2849 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
2851 #endif /* CONFIG_KGDB_KDB */