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->signal->group_stop_count > 0 ||
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 * allocate a new signal queue record
228 * - this may be called without locks if and only if t == current, otherwise an
229 * appopriate lock must be held to stop the target task from exiting
231 static struct sigqueue *
232 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
234 struct sigqueue *q = NULL;
235 struct user_struct *user;
238 * Protect access to @t credentials. This can go away when all
239 * callers hold rcu read lock.
242 user = get_uid(__task_cred(t)->user);
243 atomic_inc(&user->sigpending);
246 if (override_rlimit ||
247 atomic_read(&user->sigpending) <=
248 task_rlimit(t, RLIMIT_SIGPENDING)) {
249 q = kmem_cache_alloc(sigqueue_cachep, flags);
251 print_dropped_signal(sig);
254 if (unlikely(q == NULL)) {
255 atomic_dec(&user->sigpending);
258 INIT_LIST_HEAD(&q->list);
266 static void __sigqueue_free(struct sigqueue *q)
268 if (q->flags & SIGQUEUE_PREALLOC)
270 atomic_dec(&q->user->sigpending);
272 kmem_cache_free(sigqueue_cachep, q);
275 void flush_sigqueue(struct sigpending *queue)
279 sigemptyset(&queue->signal);
280 while (!list_empty(&queue->list)) {
281 q = list_entry(queue->list.next, struct sigqueue , list);
282 list_del_init(&q->list);
288 * Flush all pending signals for a task.
290 void __flush_signals(struct task_struct *t)
292 clear_tsk_thread_flag(t, TIF_SIGPENDING);
293 flush_sigqueue(&t->pending);
294 flush_sigqueue(&t->signal->shared_pending);
297 void flush_signals(struct task_struct *t)
301 spin_lock_irqsave(&t->sighand->siglock, flags);
303 spin_unlock_irqrestore(&t->sighand->siglock, flags);
306 static void __flush_itimer_signals(struct sigpending *pending)
308 sigset_t signal, retain;
309 struct sigqueue *q, *n;
311 signal = pending->signal;
312 sigemptyset(&retain);
314 list_for_each_entry_safe(q, n, &pending->list, list) {
315 int sig = q->info.si_signo;
317 if (likely(q->info.si_code != SI_TIMER)) {
318 sigaddset(&retain, sig);
320 sigdelset(&signal, sig);
321 list_del_init(&q->list);
326 sigorsets(&pending->signal, &signal, &retain);
329 void flush_itimer_signals(void)
331 struct task_struct *tsk = current;
334 spin_lock_irqsave(&tsk->sighand->siglock, flags);
335 __flush_itimer_signals(&tsk->pending);
336 __flush_itimer_signals(&tsk->signal->shared_pending);
337 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
340 void ignore_signals(struct task_struct *t)
344 for (i = 0; i < _NSIG; ++i)
345 t->sighand->action[i].sa.sa_handler = SIG_IGN;
351 * Flush all handlers for a task.
355 flush_signal_handlers(struct task_struct *t, int force_default)
358 struct k_sigaction *ka = &t->sighand->action[0];
359 for (i = _NSIG ; i != 0 ; i--) {
360 if (force_default || ka->sa.sa_handler != SIG_IGN)
361 ka->sa.sa_handler = SIG_DFL;
363 sigemptyset(&ka->sa.sa_mask);
368 int unhandled_signal(struct task_struct *tsk, int sig)
370 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
371 if (is_global_init(tsk))
373 if (handler != SIG_IGN && handler != SIG_DFL)
375 return !tracehook_consider_fatal_signal(tsk, sig);
379 /* Notify the system that a driver wants to block all signals for this
380 * process, and wants to be notified if any signals at all were to be
381 * sent/acted upon. If the notifier routine returns non-zero, then the
382 * signal will be acted upon after all. If the notifier routine returns 0,
383 * then then signal will be blocked. Only one block per process is
384 * allowed. priv is a pointer to private data that the notifier routine
385 * can use to determine if the signal should be blocked or not. */
388 block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
392 spin_lock_irqsave(¤t->sighand->siglock, flags);
393 current->notifier_mask = mask;
394 current->notifier_data = priv;
395 current->notifier = notifier;
396 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
399 /* Notify the system that blocking has ended. */
402 unblock_all_signals(void)
406 spin_lock_irqsave(¤t->sighand->siglock, flags);
407 current->notifier = NULL;
408 current->notifier_data = NULL;
410 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
413 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
415 struct sigqueue *q, *first = NULL;
418 * Collect the siginfo appropriate to this signal. Check if
419 * there is another siginfo for the same signal.
421 list_for_each_entry(q, &list->list, list) {
422 if (q->info.si_signo == sig) {
429 sigdelset(&list->signal, sig);
433 list_del_init(&first->list);
434 copy_siginfo(info, &first->info);
435 __sigqueue_free(first);
437 /* Ok, it wasn't in the queue. This must be
438 a fast-pathed signal or we must have been
439 out of queue space. So zero out the info.
441 info->si_signo = sig;
443 info->si_code = SI_USER;
449 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
452 int sig = next_signal(pending, mask);
455 if (current->notifier) {
456 if (sigismember(current->notifier_mask, sig)) {
457 if (!(current->notifier)(current->notifier_data)) {
458 clear_thread_flag(TIF_SIGPENDING);
464 collect_signal(sig, pending, info);
471 * Dequeue a signal and return the element to the caller, which is
472 * expected to free it.
474 * All callers have to hold the siglock.
476 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
480 /* We only dequeue private signals from ourselves, we don't let
481 * signalfd steal them
483 signr = __dequeue_signal(&tsk->pending, mask, info);
485 signr = __dequeue_signal(&tsk->signal->shared_pending,
490 * itimers are process shared and we restart periodic
491 * itimers in the signal delivery path to prevent DoS
492 * attacks in the high resolution timer case. This is
493 * compliant with the old way of self restarting
494 * itimers, as the SIGALRM is a legacy signal and only
495 * queued once. Changing the restart behaviour to
496 * restart the timer in the signal dequeue path is
497 * reducing the timer noise on heavy loaded !highres
500 if (unlikely(signr == SIGALRM)) {
501 struct hrtimer *tmr = &tsk->signal->real_timer;
503 if (!hrtimer_is_queued(tmr) &&
504 tsk->signal->it_real_incr.tv64 != 0) {
505 hrtimer_forward(tmr, tmr->base->get_time(),
506 tsk->signal->it_real_incr);
507 hrtimer_restart(tmr);
516 if (unlikely(sig_kernel_stop(signr))) {
518 * Set a marker that we have dequeued a stop signal. Our
519 * caller might release the siglock and then the pending
520 * stop signal it is about to process is no longer in the
521 * pending bitmasks, but must still be cleared by a SIGCONT
522 * (and overruled by a SIGKILL). So those cases clear this
523 * shared flag after we've set it. Note that this flag may
524 * remain set after the signal we return is ignored or
525 * handled. That doesn't matter because its only purpose
526 * is to alert stop-signal processing code when another
527 * processor has come along and cleared the flag.
529 tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
531 if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
533 * Release the siglock to ensure proper locking order
534 * of timer locks outside of siglocks. Note, we leave
535 * irqs disabled here, since the posix-timers code is
536 * about to disable them again anyway.
538 spin_unlock(&tsk->sighand->siglock);
539 do_schedule_next_timer(info);
540 spin_lock(&tsk->sighand->siglock);
546 * Tell a process that it has a new active signal..
548 * NOTE! we rely on the previous spin_lock to
549 * lock interrupts for us! We can only be called with
550 * "siglock" held, and the local interrupt must
551 * have been disabled when that got acquired!
553 * No need to set need_resched since signal event passing
554 * goes through ->blocked
556 void signal_wake_up(struct task_struct *t, int resume)
560 set_tsk_thread_flag(t, TIF_SIGPENDING);
563 * For SIGKILL, we want to wake it up in the stopped/traced/killable
564 * case. We don't check t->state here because there is a race with it
565 * executing another processor and just now entering stopped state.
566 * By using wake_up_state, we ensure the process will wake up and
567 * handle its death signal.
569 mask = TASK_INTERRUPTIBLE;
571 mask |= TASK_WAKEKILL;
572 if (!wake_up_state(t, mask))
577 * Remove signals in mask from the pending set and queue.
578 * Returns 1 if any signals were found.
580 * All callers must be holding the siglock.
582 * This version takes a sigset mask and looks at all signals,
583 * not just those in the first mask word.
585 static int rm_from_queue_full(sigset_t *mask, struct sigpending *s)
587 struct sigqueue *q, *n;
590 sigandsets(&m, mask, &s->signal);
591 if (sigisemptyset(&m))
594 signandsets(&s->signal, &s->signal, mask);
595 list_for_each_entry_safe(q, n, &s->list, list) {
596 if (sigismember(mask, q->info.si_signo)) {
597 list_del_init(&q->list);
604 * Remove signals in mask from the pending set and queue.
605 * Returns 1 if any signals were found.
607 * All callers must be holding the siglock.
609 static int rm_from_queue(unsigned long mask, struct sigpending *s)
611 struct sigqueue *q, *n;
613 if (!sigtestsetmask(&s->signal, mask))
616 sigdelsetmask(&s->signal, mask);
617 list_for_each_entry_safe(q, n, &s->list, list) {
618 if (q->info.si_signo < SIGRTMIN &&
619 (mask & sigmask(q->info.si_signo))) {
620 list_del_init(&q->list);
627 static inline int is_si_special(const struct siginfo *info)
629 return info <= SEND_SIG_FORCED;
632 static inline bool si_fromuser(const struct siginfo *info)
634 return info == SEND_SIG_NOINFO ||
635 (!is_si_special(info) && SI_FROMUSER(info));
639 * Bad permissions for sending the signal
640 * - the caller must hold the RCU read lock
642 static int check_kill_permission(int sig, struct siginfo *info,
643 struct task_struct *t)
645 const struct cred *cred, *tcred;
649 if (!valid_signal(sig))
652 if (!si_fromuser(info))
655 error = audit_signal_info(sig, t); /* Let audit system see the signal */
659 cred = current_cred();
660 tcred = __task_cred(t);
661 if (!same_thread_group(current, t) &&
662 (cred->euid ^ tcred->suid) &&
663 (cred->euid ^ tcred->uid) &&
664 (cred->uid ^ tcred->suid) &&
665 (cred->uid ^ tcred->uid) &&
666 !capable(CAP_KILL)) {
669 sid = task_session(t);
671 * We don't return the error if sid == NULL. The
672 * task was unhashed, the caller must notice this.
674 if (!sid || sid == task_session(current))
681 return security_task_kill(t, info, sig, 0);
685 * Handle magic process-wide effects of stop/continue signals. Unlike
686 * the signal actions, these happen immediately at signal-generation
687 * time regardless of blocking, ignoring, or handling. This does the
688 * actual continuing for SIGCONT, but not the actual stopping for stop
689 * signals. The process stop is done as a signal action for SIG_DFL.
691 * Returns true if the signal should be actually delivered, otherwise
692 * it should be dropped.
694 static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns)
696 struct signal_struct *signal = p->signal;
697 struct task_struct *t;
699 if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) {
701 * The process is in the middle of dying, nothing to do.
703 } else if (sig_kernel_stop(sig)) {
705 * This is a stop signal. Remove SIGCONT from all queues.
707 rm_from_queue(sigmask(SIGCONT), &signal->shared_pending);
710 rm_from_queue(sigmask(SIGCONT), &t->pending);
711 } while_each_thread(p, t);
712 } else if (sig == SIGCONT) {
715 * Remove all stop signals from all queues,
716 * and wake all threads.
718 rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
722 rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
724 * If there is a handler for SIGCONT, we must make
725 * sure that no thread returns to user mode before
726 * we post the signal, in case it was the only
727 * thread eligible to run the signal handler--then
728 * it must not do anything between resuming and
729 * running the handler. With the TIF_SIGPENDING
730 * flag set, the thread will pause and acquire the
731 * siglock that we hold now and until we've queued
732 * the pending signal.
734 * Wake up the stopped thread _after_ setting
737 state = __TASK_STOPPED;
738 if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) {
739 set_tsk_thread_flag(t, TIF_SIGPENDING);
740 state |= TASK_INTERRUPTIBLE;
742 wake_up_state(t, state);
743 } while_each_thread(p, t);
746 * Notify the parent with CLD_CONTINUED if we were stopped.
748 * If we were in the middle of a group stop, we pretend it
749 * was already finished, and then continued. Since SIGCHLD
750 * doesn't queue we report only CLD_STOPPED, as if the next
751 * CLD_CONTINUED was dropped.
754 if (signal->flags & SIGNAL_STOP_STOPPED)
755 why |= SIGNAL_CLD_CONTINUED;
756 else if (signal->group_stop_count)
757 why |= SIGNAL_CLD_STOPPED;
761 * The first thread which returns from do_signal_stop()
762 * will take ->siglock, notice SIGNAL_CLD_MASK, and
763 * notify its parent. See get_signal_to_deliver().
765 signal->flags = why | SIGNAL_STOP_CONTINUED;
766 signal->group_stop_count = 0;
767 signal->group_exit_code = 0;
770 * We are not stopped, but there could be a stop
771 * signal in the middle of being processed after
772 * being removed from the queue. Clear that too.
774 signal->flags &= ~SIGNAL_STOP_DEQUEUED;
778 return !sig_ignored(p, sig, from_ancestor_ns);
782 * Test if P wants to take SIG. After we've checked all threads with this,
783 * it's equivalent to finding no threads not blocking SIG. Any threads not
784 * blocking SIG were ruled out because they are not running and already
785 * have pending signals. Such threads will dequeue from the shared queue
786 * as soon as they're available, so putting the signal on the shared queue
787 * will be equivalent to sending it to one such thread.
789 static inline int wants_signal(int sig, struct task_struct *p)
791 if (sigismember(&p->blocked, sig))
793 if (p->flags & PF_EXITING)
797 if (task_is_stopped_or_traced(p))
799 return task_curr(p) || !signal_pending(p);
802 static void complete_signal(int sig, struct task_struct *p, int group)
804 struct signal_struct *signal = p->signal;
805 struct task_struct *t;
808 * Now find a thread we can wake up to take the signal off the queue.
810 * If the main thread wants the signal, it gets first crack.
811 * Probably the least surprising to the average bear.
813 if (wants_signal(sig, p))
815 else if (!group || thread_group_empty(p))
817 * There is just one thread and it does not need to be woken.
818 * It will dequeue unblocked signals before it runs again.
823 * Otherwise try to find a suitable thread.
825 t = signal->curr_target;
826 while (!wants_signal(sig, t)) {
828 if (t == signal->curr_target)
830 * No thread needs to be woken.
831 * Any eligible threads will see
832 * the signal in the queue soon.
836 signal->curr_target = t;
840 * Found a killable thread. If the signal will be fatal,
841 * then start taking the whole group down immediately.
843 if (sig_fatal(p, sig) &&
844 !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
845 !sigismember(&t->real_blocked, sig) &&
847 !tracehook_consider_fatal_signal(t, sig))) {
849 * This signal will be fatal to the whole group.
851 if (!sig_kernel_coredump(sig)) {
853 * Start a group exit and wake everybody up.
854 * This way we don't have other threads
855 * running and doing things after a slower
856 * thread has the fatal signal pending.
858 signal->flags = SIGNAL_GROUP_EXIT;
859 signal->group_exit_code = sig;
860 signal->group_stop_count = 0;
863 sigaddset(&t->pending.signal, SIGKILL);
864 signal_wake_up(t, 1);
865 } while_each_thread(p, t);
871 * The signal is already in the shared-pending queue.
872 * Tell the chosen thread to wake up and dequeue it.
874 signal_wake_up(t, sig == SIGKILL);
878 static inline int legacy_queue(struct sigpending *signals, int sig)
880 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
883 static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
884 int group, int from_ancestor_ns)
886 struct sigpending *pending;
890 trace_signal_generate(sig, info, t);
892 assert_spin_locked(&t->sighand->siglock);
894 if (!prepare_signal(sig, t, from_ancestor_ns))
897 pending = group ? &t->signal->shared_pending : &t->pending;
899 * Short-circuit ignored signals and support queuing
900 * exactly one non-rt signal, so that we can get more
901 * detailed information about the cause of the signal.
903 if (legacy_queue(pending, sig))
906 * fast-pathed signals for kernel-internal things like SIGSTOP
909 if (info == SEND_SIG_FORCED)
912 /* Real-time signals must be queued if sent by sigqueue, or
913 some other real-time mechanism. It is implementation
914 defined whether kill() does so. We attempt to do so, on
915 the principle of least surprise, but since kill is not
916 allowed to fail with EAGAIN when low on memory we just
917 make sure at least one signal gets delivered and don't
918 pass on the info struct. */
921 override_rlimit = (is_si_special(info) || info->si_code >= 0);
925 q = __sigqueue_alloc(sig, t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
928 list_add_tail(&q->list, &pending->list);
929 switch ((unsigned long) info) {
930 case (unsigned long) SEND_SIG_NOINFO:
931 q->info.si_signo = sig;
932 q->info.si_errno = 0;
933 q->info.si_code = SI_USER;
934 q->info.si_pid = task_tgid_nr_ns(current,
935 task_active_pid_ns(t));
936 q->info.si_uid = current_uid();
938 case (unsigned long) SEND_SIG_PRIV:
939 q->info.si_signo = sig;
940 q->info.si_errno = 0;
941 q->info.si_code = SI_KERNEL;
946 copy_siginfo(&q->info, info);
947 if (from_ancestor_ns)
951 } else if (!is_si_special(info)) {
952 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
954 * Queue overflow, abort. We may abort if the
955 * signal was rt and sent by user using something
958 trace_signal_overflow_fail(sig, group, info);
962 * This is a silent loss of information. We still
963 * send the signal, but the *info bits are lost.
965 trace_signal_lose_info(sig, group, info);
970 signalfd_notify(t, sig);
971 sigaddset(&pending->signal, sig);
972 complete_signal(sig, t, group);
976 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
979 int from_ancestor_ns = 0;
982 from_ancestor_ns = si_fromuser(info) &&
983 !task_pid_nr_ns(current, task_active_pid_ns(t));
986 return __send_signal(sig, info, t, group, from_ancestor_ns);
989 static void print_fatal_signal(struct pt_regs *regs, int signr)
991 printk("%s/%d: potentially unexpected fatal signal %d.\n",
992 current->comm, task_pid_nr(current), signr);
994 #if defined(__i386__) && !defined(__arch_um__)
995 printk("code at %08lx: ", regs->ip);
998 for (i = 0; i < 16; i++) {
1001 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1003 printk("%02x ", insn);
1013 static int __init setup_print_fatal_signals(char *str)
1015 get_option (&str, &print_fatal_signals);
1020 __setup("print-fatal-signals=", setup_print_fatal_signals);
1023 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1025 return send_signal(sig, info, p, 1);
1029 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1031 return send_signal(sig, info, t, 0);
1034 int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
1037 unsigned long flags;
1040 if (lock_task_sighand(p, &flags)) {
1041 ret = send_signal(sig, info, p, group);
1042 unlock_task_sighand(p, &flags);
1049 * Force a signal that the process can't ignore: if necessary
1050 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1052 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1053 * since we do not want to have a signal handler that was blocked
1054 * be invoked when user space had explicitly blocked it.
1056 * We don't want to have recursive SIGSEGV's etc, for example,
1057 * that is why we also clear SIGNAL_UNKILLABLE.
1060 force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
1062 unsigned long int flags;
1063 int ret, blocked, ignored;
1064 struct k_sigaction *action;
1066 spin_lock_irqsave(&t->sighand->siglock, flags);
1067 action = &t->sighand->action[sig-1];
1068 ignored = action->sa.sa_handler == SIG_IGN;
1069 blocked = sigismember(&t->blocked, sig);
1070 if (blocked || ignored) {
1071 action->sa.sa_handler = SIG_DFL;
1073 sigdelset(&t->blocked, sig);
1074 recalc_sigpending_and_wake(t);
1077 if (action->sa.sa_handler == SIG_DFL)
1078 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1079 ret = specific_send_sig_info(sig, info, t);
1080 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1086 * Nuke all other threads in the group.
1088 int zap_other_threads(struct task_struct *p)
1090 struct task_struct *t = p;
1093 p->signal->group_stop_count = 0;
1095 while_each_thread(p, t) {
1098 /* Don't bother with already dead threads */
1101 sigaddset(&t->pending.signal, SIGKILL);
1102 signal_wake_up(t, 1);
1108 struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags)
1110 struct sighand_struct *sighand;
1114 sighand = rcu_dereference(tsk->sighand);
1115 if (unlikely(sighand == NULL))
1118 spin_lock_irqsave(&sighand->siglock, *flags);
1119 if (likely(sighand == tsk->sighand))
1121 spin_unlock_irqrestore(&sighand->siglock, *flags);
1129 * send signal info to all the members of a group
1131 int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1136 ret = check_kill_permission(sig, info, p);
1140 ret = do_send_sig_info(sig, info, p, true);
1146 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1147 * control characters do (^C, ^Z etc)
1148 * - the caller must hold at least a readlock on tasklist_lock
1150 int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
1152 struct task_struct *p = NULL;
1153 int retval, success;
1157 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1158 int err = group_send_sig_info(sig, info, p);
1161 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1162 return success ? 0 : retval;
1165 int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
1168 struct task_struct *p;
1172 p = pid_task(pid, PIDTYPE_PID);
1174 error = group_send_sig_info(sig, info, p);
1175 if (unlikely(error == -ESRCH))
1177 * The task was unhashed in between, try again.
1178 * If it is dead, pid_task() will return NULL,
1179 * if we race with de_thread() it will find the
1190 kill_proc_info(int sig, struct siginfo *info, pid_t pid)
1194 error = kill_pid_info(sig, info, find_vpid(pid));
1199 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1200 int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
1201 uid_t uid, uid_t euid, u32 secid)
1204 struct task_struct *p;
1205 const struct cred *pcred;
1206 unsigned long flags;
1208 if (!valid_signal(sig))
1212 p = pid_task(pid, PIDTYPE_PID);
1217 pcred = __task_cred(p);
1218 if (si_fromuser(info) &&
1219 euid != pcred->suid && euid != pcred->uid &&
1220 uid != pcred->suid && uid != pcred->uid) {
1224 ret = security_task_kill(p, info, sig, secid);
1229 if (lock_task_sighand(p, &flags)) {
1230 ret = __send_signal(sig, info, p, 1, 0);
1231 unlock_task_sighand(p, &flags);
1239 EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
1242 * kill_something_info() interprets pid in interesting ways just like kill(2).
1244 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1245 * is probably wrong. Should make it like BSD or SYSV.
1248 static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
1254 ret = kill_pid_info(sig, info, find_vpid(pid));
1259 read_lock(&tasklist_lock);
1261 ret = __kill_pgrp_info(sig, info,
1262 pid ? find_vpid(-pid) : task_pgrp(current));
1264 int retval = 0, count = 0;
1265 struct task_struct * p;
1267 for_each_process(p) {
1268 if (task_pid_vnr(p) > 1 &&
1269 !same_thread_group(p, current)) {
1270 int err = group_send_sig_info(sig, info, p);
1276 ret = count ? retval : -ESRCH;
1278 read_unlock(&tasklist_lock);
1284 * These are for backward compatibility with the rest of the kernel source.
1288 send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
1291 * Make sure legacy kernel users don't send in bad values
1292 * (normal paths check this in check_kill_permission).
1294 if (!valid_signal(sig))
1297 return do_send_sig_info(sig, info, p, false);
1300 #define __si_special(priv) \
1301 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1304 send_sig(int sig, struct task_struct *p, int priv)
1306 return send_sig_info(sig, __si_special(priv), p);
1310 force_sig(int sig, struct task_struct *p)
1312 force_sig_info(sig, SEND_SIG_PRIV, p);
1316 * When things go south during signal handling, we
1317 * will force a SIGSEGV. And if the signal that caused
1318 * the problem was already a SIGSEGV, we'll want to
1319 * make sure we don't even try to deliver the signal..
1322 force_sigsegv(int sig, struct task_struct *p)
1324 if (sig == SIGSEGV) {
1325 unsigned long flags;
1326 spin_lock_irqsave(&p->sighand->siglock, flags);
1327 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1328 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1330 force_sig(SIGSEGV, p);
1334 int kill_pgrp(struct pid *pid, int sig, int priv)
1338 read_lock(&tasklist_lock);
1339 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1340 read_unlock(&tasklist_lock);
1344 EXPORT_SYMBOL(kill_pgrp);
1346 int kill_pid(struct pid *pid, int sig, int priv)
1348 return kill_pid_info(sig, __si_special(priv), pid);
1350 EXPORT_SYMBOL(kill_pid);
1353 * These functions support sending signals using preallocated sigqueue
1354 * structures. This is needed "because realtime applications cannot
1355 * afford to lose notifications of asynchronous events, like timer
1356 * expirations or I/O completions". In the case of Posix Timers
1357 * we allocate the sigqueue structure from the timer_create. If this
1358 * allocation fails we are able to report the failure to the application
1359 * with an EAGAIN error.
1361 struct sigqueue *sigqueue_alloc(void)
1363 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1366 q->flags |= SIGQUEUE_PREALLOC;
1371 void sigqueue_free(struct sigqueue *q)
1373 unsigned long flags;
1374 spinlock_t *lock = ¤t->sighand->siglock;
1376 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1378 * We must hold ->siglock while testing q->list
1379 * to serialize with collect_signal() or with
1380 * __exit_signal()->flush_sigqueue().
1382 spin_lock_irqsave(lock, flags);
1383 q->flags &= ~SIGQUEUE_PREALLOC;
1385 * If it is queued it will be freed when dequeued,
1386 * like the "regular" sigqueue.
1388 if (!list_empty(&q->list))
1390 spin_unlock_irqrestore(lock, flags);
1396 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1398 int sig = q->info.si_signo;
1399 struct sigpending *pending;
1400 unsigned long flags;
1403 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1406 if (!likely(lock_task_sighand(t, &flags)))
1409 ret = 1; /* the signal is ignored */
1410 if (!prepare_signal(sig, t, 0))
1414 if (unlikely(!list_empty(&q->list))) {
1416 * If an SI_TIMER entry is already queue just increment
1417 * the overrun count.
1419 BUG_ON(q->info.si_code != SI_TIMER);
1420 q->info.si_overrun++;
1423 q->info.si_overrun = 0;
1425 signalfd_notify(t, sig);
1426 pending = group ? &t->signal->shared_pending : &t->pending;
1427 list_add_tail(&q->list, &pending->list);
1428 sigaddset(&pending->signal, sig);
1429 complete_signal(sig, t, group);
1431 unlock_task_sighand(t, &flags);
1437 * Let a parent know about the death of a child.
1438 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1440 * Returns -1 if our parent ignored us and so we've switched to
1441 * self-reaping, or else @sig.
1443 int do_notify_parent(struct task_struct *tsk, int sig)
1445 struct siginfo info;
1446 unsigned long flags;
1447 struct sighand_struct *psig;
1452 /* do_notify_parent_cldstop should have been called instead. */
1453 BUG_ON(task_is_stopped_or_traced(tsk));
1455 BUG_ON(!task_ptrace(tsk) &&
1456 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1458 info.si_signo = sig;
1461 * we are under tasklist_lock here so our parent is tied to
1462 * us and cannot exit and release its namespace.
1464 * the only it can is to switch its nsproxy with sys_unshare,
1465 * bu uncharing pid namespaces is not allowed, so we'll always
1466 * see relevant namespace
1468 * write_lock() currently calls preempt_disable() which is the
1469 * same as rcu_read_lock(), but according to Oleg, this is not
1470 * correct to rely on this
1473 info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
1474 info.si_uid = __task_cred(tsk)->uid;
1477 info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime,
1478 tsk->signal->utime));
1479 info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime,
1480 tsk->signal->stime));
1482 info.si_status = tsk->exit_code & 0x7f;
1483 if (tsk->exit_code & 0x80)
1484 info.si_code = CLD_DUMPED;
1485 else if (tsk->exit_code & 0x7f)
1486 info.si_code = CLD_KILLED;
1488 info.si_code = CLD_EXITED;
1489 info.si_status = tsk->exit_code >> 8;
1492 psig = tsk->parent->sighand;
1493 spin_lock_irqsave(&psig->siglock, flags);
1494 if (!task_ptrace(tsk) && sig == SIGCHLD &&
1495 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1496 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1498 * We are exiting and our parent doesn't care. POSIX.1
1499 * defines special semantics for setting SIGCHLD to SIG_IGN
1500 * or setting the SA_NOCLDWAIT flag: we should be reaped
1501 * automatically and not left for our parent's wait4 call.
1502 * Rather than having the parent do it as a magic kind of
1503 * signal handler, we just set this to tell do_exit that we
1504 * can be cleaned up without becoming a zombie. Note that
1505 * we still call __wake_up_parent in this case, because a
1506 * blocked sys_wait4 might now return -ECHILD.
1508 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1509 * is implementation-defined: we do (if you don't want
1510 * it, just use SIG_IGN instead).
1512 ret = tsk->exit_signal = -1;
1513 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1516 if (valid_signal(sig) && sig > 0)
1517 __group_send_sig_info(sig, &info, tsk->parent);
1518 __wake_up_parent(tsk, tsk->parent);
1519 spin_unlock_irqrestore(&psig->siglock, flags);
1524 static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
1526 struct siginfo info;
1527 unsigned long flags;
1528 struct task_struct *parent;
1529 struct sighand_struct *sighand;
1531 if (task_ptrace(tsk))
1532 parent = tsk->parent;
1534 tsk = tsk->group_leader;
1535 parent = tsk->real_parent;
1538 info.si_signo = SIGCHLD;
1541 * see comment in do_notify_parent() abot the following 3 lines
1544 info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
1545 info.si_uid = __task_cred(tsk)->uid;
1548 info.si_utime = cputime_to_clock_t(tsk->utime);
1549 info.si_stime = cputime_to_clock_t(tsk->stime);
1554 info.si_status = SIGCONT;
1557 info.si_status = tsk->signal->group_exit_code & 0x7f;
1560 info.si_status = tsk->exit_code & 0x7f;
1566 sighand = parent->sighand;
1567 spin_lock_irqsave(&sighand->siglock, flags);
1568 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1569 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1570 __group_send_sig_info(SIGCHLD, &info, parent);
1572 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1574 __wake_up_parent(tsk, parent);
1575 spin_unlock_irqrestore(&sighand->siglock, flags);
1578 static inline int may_ptrace_stop(void)
1580 if (!likely(task_ptrace(current)))
1583 * Are we in the middle of do_coredump?
1584 * If so and our tracer is also part of the coredump stopping
1585 * is a deadlock situation, and pointless because our tracer
1586 * is dead so don't allow us to stop.
1587 * If SIGKILL was already sent before the caller unlocked
1588 * ->siglock we must see ->core_state != NULL. Otherwise it
1589 * is safe to enter schedule().
1591 if (unlikely(current->mm->core_state) &&
1592 unlikely(current->mm == current->parent->mm))
1599 * Return nonzero if there is a SIGKILL that should be waking us up.
1600 * Called with the siglock held.
1602 static int sigkill_pending(struct task_struct *tsk)
1604 return sigismember(&tsk->pending.signal, SIGKILL) ||
1605 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
1609 * This must be called with current->sighand->siglock held.
1611 * This should be the path for all ptrace stops.
1612 * We always set current->last_siginfo while stopped here.
1613 * That makes it a way to test a stopped process for
1614 * being ptrace-stopped vs being job-control-stopped.
1616 * If we actually decide not to stop at all because the tracer
1617 * is gone, we keep current->exit_code unless clear_code.
1619 static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
1621 if (arch_ptrace_stop_needed(exit_code, info)) {
1623 * The arch code has something special to do before a
1624 * ptrace stop. This is allowed to block, e.g. for faults
1625 * on user stack pages. We can't keep the siglock while
1626 * calling arch_ptrace_stop, so we must release it now.
1627 * To preserve proper semantics, we must do this before
1628 * any signal bookkeeping like checking group_stop_count.
1629 * Meanwhile, a SIGKILL could come in before we retake the
1630 * siglock. That must prevent us from sleeping in TASK_TRACED.
1631 * So after regaining the lock, we must check for SIGKILL.
1633 spin_unlock_irq(¤t->sighand->siglock);
1634 arch_ptrace_stop(exit_code, info);
1635 spin_lock_irq(¤t->sighand->siglock);
1636 if (sigkill_pending(current))
1641 * If there is a group stop in progress,
1642 * we must participate in the bookkeeping.
1644 if (current->signal->group_stop_count > 0)
1645 --current->signal->group_stop_count;
1647 current->last_siginfo = info;
1648 current->exit_code = exit_code;
1650 /* Let the debugger run. */
1651 __set_current_state(TASK_TRACED);
1652 spin_unlock_irq(¤t->sighand->siglock);
1653 read_lock(&tasklist_lock);
1654 if (may_ptrace_stop()) {
1655 do_notify_parent_cldstop(current, CLD_TRAPPED);
1657 * Don't want to allow preemption here, because
1658 * sys_ptrace() needs this task to be inactive.
1660 * XXX: implement read_unlock_no_resched().
1663 read_unlock(&tasklist_lock);
1664 preempt_enable_no_resched();
1668 * By the time we got the lock, our tracer went away.
1669 * Don't drop the lock yet, another tracer may come.
1671 __set_current_state(TASK_RUNNING);
1673 current->exit_code = 0;
1674 read_unlock(&tasklist_lock);
1678 * While in TASK_TRACED, we were considered "frozen enough".
1679 * Now that we woke up, it's crucial if we're supposed to be
1680 * frozen that we freeze now before running anything substantial.
1685 * We are back. Now reacquire the siglock before touching
1686 * last_siginfo, so that we are sure to have synchronized with
1687 * any signal-sending on another CPU that wants to examine it.
1689 spin_lock_irq(¤t->sighand->siglock);
1690 current->last_siginfo = NULL;
1693 * Queued signals ignored us while we were stopped for tracing.
1694 * So check for any that we should take before resuming user mode.
1695 * This sets TIF_SIGPENDING, but never clears it.
1697 recalc_sigpending_tsk(current);
1700 void ptrace_notify(int exit_code)
1704 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
1706 memset(&info, 0, sizeof info);
1707 info.si_signo = SIGTRAP;
1708 info.si_code = exit_code;
1709 info.si_pid = task_pid_vnr(current);
1710 info.si_uid = current_uid();
1712 /* Let the debugger run. */
1713 spin_lock_irq(¤t->sighand->siglock);
1714 ptrace_stop(exit_code, 1, &info);
1715 spin_unlock_irq(¤t->sighand->siglock);
1719 * This performs the stopping for SIGSTOP and other stop signals.
1720 * We have to stop all threads in the thread group.
1721 * Returns nonzero if we've actually stopped and released the siglock.
1722 * Returns zero if we didn't stop and still hold the siglock.
1724 static int do_signal_stop(int signr)
1726 struct signal_struct *sig = current->signal;
1729 if (!sig->group_stop_count) {
1730 struct task_struct *t;
1732 if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
1733 unlikely(signal_group_exit(sig)))
1736 * There is no group stop already in progress.
1737 * We must initiate one now.
1739 sig->group_exit_code = signr;
1741 sig->group_stop_count = 1;
1742 for (t = next_thread(current); t != current; t = next_thread(t))
1744 * Setting state to TASK_STOPPED for a group
1745 * stop is always done with the siglock held,
1746 * so this check has no races.
1748 if (!(t->flags & PF_EXITING) &&
1749 !task_is_stopped_or_traced(t)) {
1750 sig->group_stop_count++;
1751 signal_wake_up(t, 0);
1755 * If there are no other threads in the group, or if there is
1756 * a group stop in progress and we are the last to stop, report
1757 * to the parent. When ptraced, every thread reports itself.
1759 notify = sig->group_stop_count == 1 ? CLD_STOPPED : 0;
1760 notify = tracehook_notify_jctl(notify, CLD_STOPPED);
1762 * tracehook_notify_jctl() can drop and reacquire siglock, so
1763 * we keep ->group_stop_count != 0 before the call. If SIGCONT
1764 * or SIGKILL comes in between ->group_stop_count == 0.
1766 if (sig->group_stop_count) {
1767 if (!--sig->group_stop_count)
1768 sig->flags = SIGNAL_STOP_STOPPED;
1769 current->exit_code = sig->group_exit_code;
1770 __set_current_state(TASK_STOPPED);
1772 spin_unlock_irq(¤t->sighand->siglock);
1775 read_lock(&tasklist_lock);
1776 do_notify_parent_cldstop(current, notify);
1777 read_unlock(&tasklist_lock);
1780 /* Now we don't run again until woken by SIGCONT or SIGKILL */
1783 } while (try_to_freeze());
1785 tracehook_finish_jctl();
1786 current->exit_code = 0;
1791 static int ptrace_signal(int signr, siginfo_t *info,
1792 struct pt_regs *regs, void *cookie)
1794 if (!task_ptrace(current))
1797 ptrace_signal_deliver(regs, cookie);
1799 /* Let the debugger run. */
1800 ptrace_stop(signr, 0, info);
1802 /* We're back. Did the debugger cancel the sig? */
1803 signr = current->exit_code;
1807 current->exit_code = 0;
1809 /* Update the siginfo structure if the signal has
1810 changed. If the debugger wanted something
1811 specific in the siginfo structure then it should
1812 have updated *info via PTRACE_SETSIGINFO. */
1813 if (signr != info->si_signo) {
1814 info->si_signo = signr;
1816 info->si_code = SI_USER;
1817 info->si_pid = task_pid_vnr(current->parent);
1818 info->si_uid = task_uid(current->parent);
1821 /* If the (new) signal is now blocked, requeue it. */
1822 if (sigismember(¤t->blocked, signr)) {
1823 specific_send_sig_info(signr, info, current);
1830 int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
1831 struct pt_regs *regs, void *cookie)
1833 struct sighand_struct *sighand = current->sighand;
1834 struct signal_struct *signal = current->signal;
1839 * We'll jump back here after any time we were stopped in TASK_STOPPED.
1840 * While in TASK_STOPPED, we were considered "frozen enough".
1841 * Now that we woke up, it's crucial if we're supposed to be
1842 * frozen that we freeze now before running anything substantial.
1846 spin_lock_irq(&sighand->siglock);
1848 * Every stopped thread goes here after wakeup. Check to see if
1849 * we should notify the parent, prepare_signal(SIGCONT) encodes
1850 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
1852 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
1853 int why = (signal->flags & SIGNAL_STOP_CONTINUED)
1854 ? CLD_CONTINUED : CLD_STOPPED;
1855 signal->flags &= ~SIGNAL_CLD_MASK;
1857 why = tracehook_notify_jctl(why, CLD_CONTINUED);
1858 spin_unlock_irq(&sighand->siglock);
1861 read_lock(&tasklist_lock);
1862 do_notify_parent_cldstop(current->group_leader, why);
1863 read_unlock(&tasklist_lock);
1869 struct k_sigaction *ka;
1871 * Tracing can induce an artifical signal and choose sigaction.
1872 * The return value in @signr determines the default action,
1873 * but @info->si_signo is the signal number we will report.
1875 signr = tracehook_get_signal(current, regs, info, return_ka);
1876 if (unlikely(signr < 0))
1878 if (unlikely(signr != 0))
1881 if (unlikely(signal->group_stop_count > 0) &&
1885 signr = dequeue_signal(current, ¤t->blocked,
1889 break; /* will return 0 */
1891 if (signr != SIGKILL) {
1892 signr = ptrace_signal(signr, info,
1898 ka = &sighand->action[signr-1];
1901 /* Trace actually delivered signals. */
1902 trace_signal_deliver(signr, info, ka);
1904 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
1906 if (ka->sa.sa_handler != SIG_DFL) {
1907 /* Run the handler. */
1910 if (ka->sa.sa_flags & SA_ONESHOT)
1911 ka->sa.sa_handler = SIG_DFL;
1913 break; /* will return non-zero "signr" value */
1917 * Now we are doing the default action for this signal.
1919 if (sig_kernel_ignore(signr)) /* Default is nothing. */
1923 * Global init gets no signals it doesn't want.
1924 * Container-init gets no signals it doesn't want from same
1927 * Note that if global/container-init sees a sig_kernel_only()
1928 * signal here, the signal must have been generated internally
1929 * or must have come from an ancestor namespace. In either
1930 * case, the signal cannot be dropped.
1932 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
1933 !sig_kernel_only(signr))
1936 if (sig_kernel_stop(signr)) {
1938 * The default action is to stop all threads in
1939 * the thread group. The job control signals
1940 * do nothing in an orphaned pgrp, but SIGSTOP
1941 * always works. Note that siglock needs to be
1942 * dropped during the call to is_orphaned_pgrp()
1943 * because of lock ordering with tasklist_lock.
1944 * This allows an intervening SIGCONT to be posted.
1945 * We need to check for that and bail out if necessary.
1947 if (signr != SIGSTOP) {
1948 spin_unlock_irq(&sighand->siglock);
1950 /* signals can be posted during this window */
1952 if (is_current_pgrp_orphaned())
1955 spin_lock_irq(&sighand->siglock);
1958 if (likely(do_signal_stop(info->si_signo))) {
1959 /* It released the siglock. */
1964 * We didn't actually stop, due to a race
1965 * with SIGCONT or something like that.
1970 spin_unlock_irq(&sighand->siglock);
1973 * Anything else is fatal, maybe with a core dump.
1975 current->flags |= PF_SIGNALED;
1977 if (sig_kernel_coredump(signr)) {
1978 if (print_fatal_signals)
1979 print_fatal_signal(regs, info->si_signo);
1981 * If it was able to dump core, this kills all
1982 * other threads in the group and synchronizes with
1983 * their demise. If we lost the race with another
1984 * thread getting here, it set group_exit_code
1985 * first and our do_group_exit call below will use
1986 * that value and ignore the one we pass it.
1988 do_coredump(info->si_signo, info->si_signo, regs);
1992 * Death signals, no core dump.
1994 do_group_exit(info->si_signo);
1997 spin_unlock_irq(&sighand->siglock);
2001 void exit_signals(struct task_struct *tsk)
2004 struct task_struct *t;
2006 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2007 tsk->flags |= PF_EXITING;
2011 spin_lock_irq(&tsk->sighand->siglock);
2013 * From now this task is not visible for group-wide signals,
2014 * see wants_signal(), do_signal_stop().
2016 tsk->flags |= PF_EXITING;
2017 if (!signal_pending(tsk))
2020 /* It could be that __group_complete_signal() choose us to
2021 * notify about group-wide signal. Another thread should be
2022 * woken now to take the signal since we will not.
2024 for (t = tsk; (t = next_thread(t)) != tsk; )
2025 if (!signal_pending(t) && !(t->flags & PF_EXITING))
2026 recalc_sigpending_and_wake(t);
2028 if (unlikely(tsk->signal->group_stop_count) &&
2029 !--tsk->signal->group_stop_count) {
2030 tsk->signal->flags = SIGNAL_STOP_STOPPED;
2031 group_stop = tracehook_notify_jctl(CLD_STOPPED, CLD_STOPPED);
2034 spin_unlock_irq(&tsk->sighand->siglock);
2036 if (unlikely(group_stop)) {
2037 read_lock(&tasklist_lock);
2038 do_notify_parent_cldstop(tsk, group_stop);
2039 read_unlock(&tasklist_lock);
2043 EXPORT_SYMBOL(recalc_sigpending);
2044 EXPORT_SYMBOL_GPL(dequeue_signal);
2045 EXPORT_SYMBOL(flush_signals);
2046 EXPORT_SYMBOL(force_sig);
2047 EXPORT_SYMBOL(send_sig);
2048 EXPORT_SYMBOL(send_sig_info);
2049 EXPORT_SYMBOL(sigprocmask);
2050 EXPORT_SYMBOL(block_all_signals);
2051 EXPORT_SYMBOL(unblock_all_signals);
2055 * System call entry points.
2058 SYSCALL_DEFINE0(restart_syscall)
2060 struct restart_block *restart = ¤t_thread_info()->restart_block;
2061 return restart->fn(restart);
2064 long do_no_restart_syscall(struct restart_block *param)
2070 * We don't need to get the kernel lock - this is all local to this
2071 * particular thread.. (and that's good, because this is _heavily_
2072 * used by various programs)
2076 * This is also useful for kernel threads that want to temporarily
2077 * (or permanently) block certain signals.
2079 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2080 * interface happily blocks "unblockable" signals like SIGKILL
2083 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2087 spin_lock_irq(¤t->sighand->siglock);
2089 *oldset = current->blocked;
2094 sigorsets(¤t->blocked, ¤t->blocked, set);
2097 signandsets(¤t->blocked, ¤t->blocked, set);
2100 current->blocked = *set;
2105 recalc_sigpending();
2106 spin_unlock_irq(¤t->sighand->siglock);
2111 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set,
2112 sigset_t __user *, oset, size_t, sigsetsize)
2114 int error = -EINVAL;
2115 sigset_t old_set, new_set;
2117 /* XXX: Don't preclude handling different sized sigset_t's. */
2118 if (sigsetsize != sizeof(sigset_t))
2123 if (copy_from_user(&new_set, set, sizeof(*set)))
2125 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2127 error = sigprocmask(how, &new_set, &old_set);
2133 spin_lock_irq(¤t->sighand->siglock);
2134 old_set = current->blocked;
2135 spin_unlock_irq(¤t->sighand->siglock);
2139 if (copy_to_user(oset, &old_set, sizeof(*oset)))
2147 long do_sigpending(void __user *set, unsigned long sigsetsize)
2149 long error = -EINVAL;
2152 if (sigsetsize > sizeof(sigset_t))
2155 spin_lock_irq(¤t->sighand->siglock);
2156 sigorsets(&pending, ¤t->pending.signal,
2157 ¤t->signal->shared_pending.signal);
2158 spin_unlock_irq(¤t->sighand->siglock);
2160 /* Outside the lock because only this thread touches it. */
2161 sigandsets(&pending, ¤t->blocked, &pending);
2164 if (!copy_to_user(set, &pending, sigsetsize))
2171 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize)
2173 return do_sigpending(set, sigsetsize);
2176 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2178 int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
2182 if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
2184 if (from->si_code < 0)
2185 return __copy_to_user(to, from, sizeof(siginfo_t))
2188 * If you change siginfo_t structure, please be sure
2189 * this code is fixed accordingly.
2190 * Please remember to update the signalfd_copyinfo() function
2191 * inside fs/signalfd.c too, in case siginfo_t changes.
2192 * It should never copy any pad contained in the structure
2193 * to avoid security leaks, but must copy the generic
2194 * 3 ints plus the relevant union member.
2196 err = __put_user(from->si_signo, &to->si_signo);
2197 err |= __put_user(from->si_errno, &to->si_errno);
2198 err |= __put_user((short)from->si_code, &to->si_code);
2199 switch (from->si_code & __SI_MASK) {
2201 err |= __put_user(from->si_pid, &to->si_pid);
2202 err |= __put_user(from->si_uid, &to->si_uid);
2205 err |= __put_user(from->si_tid, &to->si_tid);
2206 err |= __put_user(from->si_overrun, &to->si_overrun);
2207 err |= __put_user(from->si_ptr, &to->si_ptr);
2210 err |= __put_user(from->si_band, &to->si_band);
2211 err |= __put_user(from->si_fd, &to->si_fd);
2214 err |= __put_user(from->si_addr, &to->si_addr);
2215 #ifdef __ARCH_SI_TRAPNO
2216 err |= __put_user(from->si_trapno, &to->si_trapno);
2220 err |= __put_user(from->si_pid, &to->si_pid);
2221 err |= __put_user(from->si_uid, &to->si_uid);
2222 err |= __put_user(from->si_status, &to->si_status);
2223 err |= __put_user(from->si_utime, &to->si_utime);
2224 err |= __put_user(from->si_stime, &to->si_stime);
2226 case __SI_RT: /* This is not generated by the kernel as of now. */
2227 case __SI_MESGQ: /* But this is */
2228 err |= __put_user(from->si_pid, &to->si_pid);
2229 err |= __put_user(from->si_uid, &to->si_uid);
2230 err |= __put_user(from->si_ptr, &to->si_ptr);
2232 default: /* this is just in case for now ... */
2233 err |= __put_user(from->si_pid, &to->si_pid);
2234 err |= __put_user(from->si_uid, &to->si_uid);
2242 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
2243 siginfo_t __user *, uinfo, const struct timespec __user *, uts,
2252 /* XXX: Don't preclude handling different sized sigset_t's. */
2253 if (sigsetsize != sizeof(sigset_t))
2256 if (copy_from_user(&these, uthese, sizeof(these)))
2260 * Invert the set of allowed signals to get those we
2263 sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP));
2267 if (copy_from_user(&ts, uts, sizeof(ts)))
2269 if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0
2274 spin_lock_irq(¤t->sighand->siglock);
2275 sig = dequeue_signal(current, &these, &info);
2277 timeout = MAX_SCHEDULE_TIMEOUT;
2279 timeout = (timespec_to_jiffies(&ts)
2280 + (ts.tv_sec || ts.tv_nsec));
2283 /* None ready -- temporarily unblock those we're
2284 * interested while we are sleeping in so that we'll
2285 * be awakened when they arrive. */
2286 current->real_blocked = current->blocked;
2287 sigandsets(¤t->blocked, ¤t->blocked, &these);
2288 recalc_sigpending();
2289 spin_unlock_irq(¤t->sighand->siglock);
2291 timeout = schedule_timeout_interruptible(timeout);
2293 spin_lock_irq(¤t->sighand->siglock);
2294 sig = dequeue_signal(current, &these, &info);
2295 current->blocked = current->real_blocked;
2296 siginitset(¤t->real_blocked, 0);
2297 recalc_sigpending();
2300 spin_unlock_irq(¤t->sighand->siglock);
2305 if (copy_siginfo_to_user(uinfo, &info))
2317 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
2319 struct siginfo info;
2321 info.si_signo = sig;
2323 info.si_code = SI_USER;
2324 info.si_pid = task_tgid_vnr(current);
2325 info.si_uid = current_uid();
2327 return kill_something_info(sig, &info, pid);
2331 do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
2333 struct task_struct *p;
2337 p = find_task_by_vpid(pid);
2338 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
2339 error = check_kill_permission(sig, info, p);
2341 * The null signal is a permissions and process existence
2342 * probe. No signal is actually delivered.
2344 if (!error && sig) {
2345 error = do_send_sig_info(sig, info, p, false);
2347 * If lock_task_sighand() failed we pretend the task
2348 * dies after receiving the signal. The window is tiny,
2349 * and the signal is private anyway.
2351 if (unlikely(error == -ESRCH))
2360 static int do_tkill(pid_t tgid, pid_t pid, int sig)
2362 struct siginfo info;
2364 info.si_signo = sig;
2366 info.si_code = SI_TKILL;
2367 info.si_pid = task_tgid_vnr(current);
2368 info.si_uid = current_uid();
2370 return do_send_specific(tgid, pid, sig, &info);
2374 * sys_tgkill - send signal to one specific thread
2375 * @tgid: the thread group ID of the thread
2376 * @pid: the PID of the thread
2377 * @sig: signal to be sent
2379 * This syscall also checks the @tgid and returns -ESRCH even if the PID
2380 * exists but it's not belonging to the target process anymore. This
2381 * method solves the problem of threads exiting and PIDs getting reused.
2383 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
2385 /* This is only valid for single tasks */
2386 if (pid <= 0 || tgid <= 0)
2389 return do_tkill(tgid, pid, sig);
2393 * Send a signal to only one task, even if it's a CLONE_THREAD task.
2395 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
2397 /* This is only valid for single tasks */
2401 return do_tkill(0, pid, sig);
2404 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
2405 siginfo_t __user *, uinfo)
2409 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2412 /* Not even root can pretend to send signals from the kernel.
2413 Nor can they impersonate a kill(), which adds source info. */
2414 if (info.si_code >= 0)
2416 info.si_signo = sig;
2418 /* POSIX.1b doesn't mention process groups. */
2419 return kill_proc_info(sig, &info, pid);
2422 long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
2424 /* This is only valid for single tasks */
2425 if (pid <= 0 || tgid <= 0)
2428 /* Not even root can pretend to send signals from the kernel.
2429 Nor can they impersonate a kill(), which adds source info. */
2430 if (info->si_code >= 0)
2432 info->si_signo = sig;
2434 return do_send_specific(tgid, pid, sig, info);
2437 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
2438 siginfo_t __user *, uinfo)
2442 if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
2445 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
2448 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
2450 struct task_struct *t = current;
2451 struct k_sigaction *k;
2454 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
2457 k = &t->sighand->action[sig-1];
2459 spin_lock_irq(¤t->sighand->siglock);
2464 sigdelsetmask(&act->sa.sa_mask,
2465 sigmask(SIGKILL) | sigmask(SIGSTOP));
2469 * "Setting a signal action to SIG_IGN for a signal that is
2470 * pending shall cause the pending signal to be discarded,
2471 * whether or not it is blocked."
2473 * "Setting a signal action to SIG_DFL for a signal that is
2474 * pending and whose default action is to ignore the signal
2475 * (for example, SIGCHLD), shall cause the pending signal to
2476 * be discarded, whether or not it is blocked"
2478 if (sig_handler_ignored(sig_handler(t, sig), sig)) {
2480 sigaddset(&mask, sig);
2481 rm_from_queue_full(&mask, &t->signal->shared_pending);
2483 rm_from_queue_full(&mask, &t->pending);
2485 } while (t != current);
2489 spin_unlock_irq(¤t->sighand->siglock);
2494 do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
2499 oss.ss_sp = (void __user *) current->sas_ss_sp;
2500 oss.ss_size = current->sas_ss_size;
2501 oss.ss_flags = sas_ss_flags(sp);
2509 if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
2511 error = __get_user(ss_sp, &uss->ss_sp) |
2512 __get_user(ss_flags, &uss->ss_flags) |
2513 __get_user(ss_size, &uss->ss_size);
2518 if (on_sig_stack(sp))
2524 * Note - this code used to test ss_flags incorrectly
2525 * old code may have been written using ss_flags==0
2526 * to mean ss_flags==SS_ONSTACK (as this was the only
2527 * way that worked) - this fix preserves that older
2530 if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
2533 if (ss_flags == SS_DISABLE) {
2538 if (ss_size < MINSIGSTKSZ)
2542 current->sas_ss_sp = (unsigned long) ss_sp;
2543 current->sas_ss_size = ss_size;
2549 if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
2551 error = __put_user(oss.ss_sp, &uoss->ss_sp) |
2552 __put_user(oss.ss_size, &uoss->ss_size) |
2553 __put_user(oss.ss_flags, &uoss->ss_flags);
2560 #ifdef __ARCH_WANT_SYS_SIGPENDING
2562 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
2564 return do_sigpending(set, sizeof(*set));
2569 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
2570 /* Some platforms have their own version with special arguments others
2571 support only sys_rt_sigprocmask. */
2573 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set,
2574 old_sigset_t __user *, oset)
2577 old_sigset_t old_set, new_set;
2581 if (copy_from_user(&new_set, set, sizeof(*set)))
2583 new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
2585 spin_lock_irq(¤t->sighand->siglock);
2586 old_set = current->blocked.sig[0];
2594 sigaddsetmask(¤t->blocked, new_set);
2597 sigdelsetmask(¤t->blocked, new_set);
2600 current->blocked.sig[0] = new_set;
2604 recalc_sigpending();
2605 spin_unlock_irq(¤t->sighand->siglock);
2611 old_set = current->blocked.sig[0];
2614 if (copy_to_user(oset, &old_set, sizeof(*oset)))
2621 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
2623 #ifdef __ARCH_WANT_SYS_RT_SIGACTION
2624 SYSCALL_DEFINE4(rt_sigaction, int, sig,
2625 const struct sigaction __user *, act,
2626 struct sigaction __user *, oact,
2629 struct k_sigaction new_sa, old_sa;
2632 /* XXX: Don't preclude handling different sized sigset_t's. */
2633 if (sigsetsize != sizeof(sigset_t))
2637 if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
2641 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
2644 if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
2650 #endif /* __ARCH_WANT_SYS_RT_SIGACTION */
2652 #ifdef __ARCH_WANT_SYS_SGETMASK
2655 * For backwards compatibility. Functionality superseded by sigprocmask.
2657 SYSCALL_DEFINE0(sgetmask)
2660 return current->blocked.sig[0];
2663 SYSCALL_DEFINE1(ssetmask, int, newmask)
2667 spin_lock_irq(¤t->sighand->siglock);
2668 old = current->blocked.sig[0];
2670 siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)|
2672 recalc_sigpending();
2673 spin_unlock_irq(¤t->sighand->siglock);
2677 #endif /* __ARCH_WANT_SGETMASK */
2679 #ifdef __ARCH_WANT_SYS_SIGNAL
2681 * For backwards compatibility. Functionality superseded by sigaction.
2683 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
2685 struct k_sigaction new_sa, old_sa;
2688 new_sa.sa.sa_handler = handler;
2689 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
2690 sigemptyset(&new_sa.sa.sa_mask);
2692 ret = do_sigaction(sig, &new_sa, &old_sa);
2694 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
2696 #endif /* __ARCH_WANT_SYS_SIGNAL */
2698 #ifdef __ARCH_WANT_SYS_PAUSE
2700 SYSCALL_DEFINE0(pause)
2702 current->state = TASK_INTERRUPTIBLE;
2704 return -ERESTARTNOHAND;
2709 #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
2710 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
2714 /* XXX: Don't preclude handling different sized sigset_t's. */
2715 if (sigsetsize != sizeof(sigset_t))
2718 if (copy_from_user(&newset, unewset, sizeof(newset)))
2720 sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));
2722 spin_lock_irq(¤t->sighand->siglock);
2723 current->saved_sigmask = current->blocked;
2724 current->blocked = newset;
2725 recalc_sigpending();
2726 spin_unlock_irq(¤t->sighand->siglock);
2728 current->state = TASK_INTERRUPTIBLE;
2730 set_restore_sigmask();
2731 return -ERESTARTNOHAND;
2733 #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */
2735 __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma)
2740 void __init signals_init(void)
2742 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
2745 #ifdef CONFIG_KGDB_KDB
2746 #include <linux/kdb.h>
2748 * kdb_send_sig_info - Allows kdb to send signals without exposing
2749 * signal internals. This function checks if the required locks are
2750 * available before calling the main signal code, to avoid kdb
2754 kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
2756 static struct task_struct *kdb_prev_t;
2758 if (!spin_trylock(&t->sighand->siglock)) {
2759 kdb_printf("Can't do kill command now.\n"
2760 "The sigmask lock is held somewhere else in "
2761 "kernel, try again later\n");
2764 spin_unlock(&t->sighand->siglock);
2765 new_t = kdb_prev_t != t;
2767 if (t->state != TASK_RUNNING && new_t) {
2768 kdb_printf("Process is not RUNNING, sending a signal from "
2769 "kdb risks deadlock\n"
2770 "on the run queue locks. "
2771 "The signal has _not_ been sent.\n"
2772 "Reissue the kill command if you want to risk "
2776 sig = info->si_signo;
2777 if (send_sig_info(sig, info, t))
2778 kdb_printf("Fail to deliver Signal %d to process %d.\n",
2781 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
2783 #endif /* CONFIG_KGDB_KDB */