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/export.h>
15 #include <linux/init.h>
16 #include <linux/sched/mm.h>
17 #include <linux/sched/user.h>
18 #include <linux/sched/debug.h>
19 #include <linux/sched/task.h>
20 #include <linux/sched/task_stack.h>
21 #include <linux/sched/cputime.h>
22 #include <linux/file.h>
24 #include <linux/proc_fs.h>
25 #include <linux/tty.h>
26 #include <linux/binfmts.h>
27 #include <linux/coredump.h>
28 #include <linux/security.h>
29 #include <linux/syscalls.h>
30 #include <linux/ptrace.h>
31 #include <linux/signal.h>
32 #include <linux/signalfd.h>
33 #include <linux/ratelimit.h>
34 #include <linux/tracehook.h>
35 #include <linux/capability.h>
36 #include <linux/freezer.h>
37 #include <linux/pid_namespace.h>
38 #include <linux/nsproxy.h>
39 #include <linux/user_namespace.h>
40 #include <linux/uprobes.h>
41 #include <linux/compat.h>
42 #include <linux/cn_proc.h>
43 #include <linux/compiler.h>
44 #include <linux/posix-timers.h>
45 #include <linux/livepatch.h>
46 #include <linux/cgroup.h>
48 #define CREATE_TRACE_POINTS
49 #include <trace/events/signal.h>
51 #include <asm/param.h>
52 #include <linux/uaccess.h>
53 #include <asm/unistd.h>
54 #include <asm/siginfo.h>
55 #include <asm/cacheflush.h>
56 #include "audit.h" /* audit_signal_info() */
59 * SLAB caches for signal bits.
62 static struct kmem_cache *sigqueue_cachep;
64 int print_fatal_signals __read_mostly;
66 static void __user *sig_handler(struct task_struct *t, int sig)
68 return t->sighand->action[sig - 1].sa.sa_handler;
71 static inline bool sig_handler_ignored(void __user *handler, int sig)
73 /* Is it explicitly or implicitly ignored? */
74 return handler == SIG_IGN ||
75 (handler == SIG_DFL && sig_kernel_ignore(sig));
78 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
82 handler = sig_handler(t, sig);
84 /* SIGKILL and SIGSTOP may not be sent to the global init */
85 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
88 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
89 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
92 return sig_handler_ignored(handler, sig);
95 static bool sig_ignored(struct task_struct *t, int sig, bool force)
98 * Blocked signals are never ignored, since the
99 * signal handler may change by the time it is
102 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
106 * Tracers may want to know about even ignored signal unless it
107 * is SIGKILL which can't be reported anyway but can be ignored
108 * by SIGNAL_UNKILLABLE task.
110 if (t->ptrace && sig != SIGKILL)
113 return sig_task_ignored(t, sig, force);
117 * Re-calculate pending state from the set of locally pending
118 * signals, globally pending signals, and blocked signals.
120 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
125 switch (_NSIG_WORDS) {
127 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
128 ready |= signal->sig[i] &~ blocked->sig[i];
131 case 4: ready = signal->sig[3] &~ blocked->sig[3];
132 ready |= signal->sig[2] &~ blocked->sig[2];
133 ready |= signal->sig[1] &~ blocked->sig[1];
134 ready |= signal->sig[0] &~ blocked->sig[0];
137 case 2: ready = signal->sig[1] &~ blocked->sig[1];
138 ready |= signal->sig[0] &~ blocked->sig[0];
141 case 1: ready = signal->sig[0] &~ blocked->sig[0];
146 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
148 static bool recalc_sigpending_tsk(struct task_struct *t)
150 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
151 PENDING(&t->pending, &t->blocked) ||
152 PENDING(&t->signal->shared_pending, &t->blocked) ||
153 cgroup_task_frozen(t)) {
154 set_tsk_thread_flag(t, TIF_SIGPENDING);
159 * We must never clear the flag in another thread, or in current
160 * when it's possible the current syscall is returning -ERESTART*.
161 * So we don't clear it here, and only callers who know they should do.
167 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
168 * This is superfluous when called on current, the wakeup is a harmless no-op.
170 void recalc_sigpending_and_wake(struct task_struct *t)
172 if (recalc_sigpending_tsk(t))
173 signal_wake_up(t, 0);
176 void recalc_sigpending(void)
178 if (!recalc_sigpending_tsk(current) && !freezing(current) &&
179 !klp_patch_pending(current))
180 clear_thread_flag(TIF_SIGPENDING);
183 EXPORT_SYMBOL(recalc_sigpending);
185 void calculate_sigpending(void)
187 /* Have any signals or users of TIF_SIGPENDING been delayed
190 spin_lock_irq(¤t->sighand->siglock);
191 set_tsk_thread_flag(current, TIF_SIGPENDING);
193 spin_unlock_irq(¤t->sighand->siglock);
196 /* Given the mask, find the first available signal that should be serviced. */
198 #define SYNCHRONOUS_MASK \
199 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
200 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
202 int next_signal(struct sigpending *pending, sigset_t *mask)
204 unsigned long i, *s, *m, x;
207 s = pending->signal.sig;
211 * Handle the first word specially: it contains the
212 * synchronous signals that need to be dequeued first.
216 if (x & SYNCHRONOUS_MASK)
217 x &= SYNCHRONOUS_MASK;
222 switch (_NSIG_WORDS) {
224 for (i = 1; i < _NSIG_WORDS; ++i) {
228 sig = ffz(~x) + i*_NSIG_BPW + 1;
237 sig = ffz(~x) + _NSIG_BPW + 1;
248 static inline void print_dropped_signal(int sig)
250 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
252 if (!print_fatal_signals)
255 if (!__ratelimit(&ratelimit_state))
258 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
259 current->comm, current->pid, sig);
263 * task_set_jobctl_pending - set jobctl pending bits
265 * @mask: pending bits to set
267 * Clear @mask from @task->jobctl. @mask must be subset of
268 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
269 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
270 * cleared. If @task is already being killed or exiting, this function
274 * Must be called with @task->sighand->siglock held.
277 * %true if @mask is set, %false if made noop because @task was dying.
279 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
281 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
282 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
283 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
285 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
288 if (mask & JOBCTL_STOP_SIGMASK)
289 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
291 task->jobctl |= mask;
296 * task_clear_jobctl_trapping - clear jobctl trapping bit
299 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
300 * Clear it and wake up the ptracer. Note that we don't need any further
301 * locking. @task->siglock guarantees that @task->parent points to the
305 * Must be called with @task->sighand->siglock held.
307 void task_clear_jobctl_trapping(struct task_struct *task)
309 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
310 task->jobctl &= ~JOBCTL_TRAPPING;
311 smp_mb(); /* advised by wake_up_bit() */
312 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
317 * task_clear_jobctl_pending - clear jobctl pending bits
319 * @mask: pending bits to clear
321 * Clear @mask from @task->jobctl. @mask must be subset of
322 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
323 * STOP bits are cleared together.
325 * If clearing of @mask leaves no stop or trap pending, this function calls
326 * task_clear_jobctl_trapping().
329 * Must be called with @task->sighand->siglock held.
331 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
333 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
335 if (mask & JOBCTL_STOP_PENDING)
336 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
338 task->jobctl &= ~mask;
340 if (!(task->jobctl & JOBCTL_PENDING_MASK))
341 task_clear_jobctl_trapping(task);
345 * task_participate_group_stop - participate in a group stop
346 * @task: task participating in a group stop
348 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
349 * Group stop states are cleared and the group stop count is consumed if
350 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
351 * stop, the appropriate %SIGNAL_* flags are set.
354 * Must be called with @task->sighand->siglock held.
357 * %true if group stop completion should be notified to the parent, %false
360 static bool task_participate_group_stop(struct task_struct *task)
362 struct signal_struct *sig = task->signal;
363 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
365 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
367 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
372 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
373 sig->group_stop_count--;
376 * Tell the caller to notify completion iff we are entering into a
377 * fresh group stop. Read comment in do_signal_stop() for details.
379 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
380 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
386 void task_join_group_stop(struct task_struct *task)
388 /* Have the new thread join an on-going signal group stop */
389 unsigned long jobctl = current->jobctl;
390 if (jobctl & JOBCTL_STOP_PENDING) {
391 struct signal_struct *sig = current->signal;
392 unsigned long signr = jobctl & JOBCTL_STOP_SIGMASK;
393 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
394 if (task_set_jobctl_pending(task, signr | gstop)) {
395 sig->group_stop_count++;
401 * allocate a new signal queue record
402 * - this may be called without locks if and only if t == current, otherwise an
403 * appropriate lock must be held to stop the target task from exiting
405 static struct sigqueue *
406 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
408 struct sigqueue *q = NULL;
409 struct user_struct *user;
412 * Protect access to @t credentials. This can go away when all
413 * callers hold rcu read lock.
416 user = get_uid(__task_cred(t)->user);
417 atomic_inc(&user->sigpending);
420 if (override_rlimit ||
421 atomic_read(&user->sigpending) <=
422 task_rlimit(t, RLIMIT_SIGPENDING)) {
423 q = kmem_cache_alloc(sigqueue_cachep, flags);
425 print_dropped_signal(sig);
428 if (unlikely(q == NULL)) {
429 atomic_dec(&user->sigpending);
432 INIT_LIST_HEAD(&q->list);
440 static void __sigqueue_free(struct sigqueue *q)
442 if (q->flags & SIGQUEUE_PREALLOC)
444 atomic_dec(&q->user->sigpending);
446 kmem_cache_free(sigqueue_cachep, q);
449 void flush_sigqueue(struct sigpending *queue)
453 sigemptyset(&queue->signal);
454 while (!list_empty(&queue->list)) {
455 q = list_entry(queue->list.next, struct sigqueue , list);
456 list_del_init(&q->list);
462 * Flush all pending signals for this kthread.
464 void flush_signals(struct task_struct *t)
468 spin_lock_irqsave(&t->sighand->siglock, flags);
469 clear_tsk_thread_flag(t, TIF_SIGPENDING);
470 flush_sigqueue(&t->pending);
471 flush_sigqueue(&t->signal->shared_pending);
472 spin_unlock_irqrestore(&t->sighand->siglock, flags);
474 EXPORT_SYMBOL(flush_signals);
476 #ifdef CONFIG_POSIX_TIMERS
477 static void __flush_itimer_signals(struct sigpending *pending)
479 sigset_t signal, retain;
480 struct sigqueue *q, *n;
482 signal = pending->signal;
483 sigemptyset(&retain);
485 list_for_each_entry_safe(q, n, &pending->list, list) {
486 int sig = q->info.si_signo;
488 if (likely(q->info.si_code != SI_TIMER)) {
489 sigaddset(&retain, sig);
491 sigdelset(&signal, sig);
492 list_del_init(&q->list);
497 sigorsets(&pending->signal, &signal, &retain);
500 void flush_itimer_signals(void)
502 struct task_struct *tsk = current;
505 spin_lock_irqsave(&tsk->sighand->siglock, flags);
506 __flush_itimer_signals(&tsk->pending);
507 __flush_itimer_signals(&tsk->signal->shared_pending);
508 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
512 void ignore_signals(struct task_struct *t)
516 for (i = 0; i < _NSIG; ++i)
517 t->sighand->action[i].sa.sa_handler = SIG_IGN;
523 * Flush all handlers for a task.
527 flush_signal_handlers(struct task_struct *t, int force_default)
530 struct k_sigaction *ka = &t->sighand->action[0];
531 for (i = _NSIG ; i != 0 ; i--) {
532 if (force_default || ka->sa.sa_handler != SIG_IGN)
533 ka->sa.sa_handler = SIG_DFL;
535 #ifdef __ARCH_HAS_SA_RESTORER
536 ka->sa.sa_restorer = NULL;
538 sigemptyset(&ka->sa.sa_mask);
543 bool unhandled_signal(struct task_struct *tsk, int sig)
545 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
546 if (is_global_init(tsk))
549 if (handler != SIG_IGN && handler != SIG_DFL)
552 /* if ptraced, let the tracer determine */
556 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
559 struct sigqueue *q, *first = NULL;
562 * Collect the siginfo appropriate to this signal. Check if
563 * there is another siginfo for the same signal.
565 list_for_each_entry(q, &list->list, list) {
566 if (q->info.si_signo == sig) {
573 sigdelset(&list->signal, sig);
577 list_del_init(&first->list);
578 copy_siginfo(info, &first->info);
581 (first->flags & SIGQUEUE_PREALLOC) &&
582 (info->si_code == SI_TIMER) &&
583 (info->si_sys_private);
585 __sigqueue_free(first);
588 * Ok, it wasn't in the queue. This must be
589 * a fast-pathed signal or we must have been
590 * out of queue space. So zero out the info.
593 info->si_signo = sig;
595 info->si_code = SI_USER;
601 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
602 kernel_siginfo_t *info, bool *resched_timer)
604 int sig = next_signal(pending, mask);
607 collect_signal(sig, pending, info, resched_timer);
612 * Dequeue a signal and return the element to the caller, which is
613 * expected to free it.
615 * All callers have to hold the siglock.
617 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
619 bool resched_timer = false;
622 /* We only dequeue private signals from ourselves, we don't let
623 * signalfd steal them
625 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
627 signr = __dequeue_signal(&tsk->signal->shared_pending,
628 mask, info, &resched_timer);
629 #ifdef CONFIG_POSIX_TIMERS
633 * itimers are process shared and we restart periodic
634 * itimers in the signal delivery path to prevent DoS
635 * attacks in the high resolution timer case. This is
636 * compliant with the old way of self-restarting
637 * itimers, as the SIGALRM is a legacy signal and only
638 * queued once. Changing the restart behaviour to
639 * restart the timer in the signal dequeue path is
640 * reducing the timer noise on heavy loaded !highres
643 if (unlikely(signr == SIGALRM)) {
644 struct hrtimer *tmr = &tsk->signal->real_timer;
646 if (!hrtimer_is_queued(tmr) &&
647 tsk->signal->it_real_incr != 0) {
648 hrtimer_forward(tmr, tmr->base->get_time(),
649 tsk->signal->it_real_incr);
650 hrtimer_restart(tmr);
660 if (unlikely(sig_kernel_stop(signr))) {
662 * Set a marker that we have dequeued a stop signal. Our
663 * caller might release the siglock and then the pending
664 * stop signal it is about to process is no longer in the
665 * pending bitmasks, but must still be cleared by a SIGCONT
666 * (and overruled by a SIGKILL). So those cases clear this
667 * shared flag after we've set it. Note that this flag may
668 * remain set after the signal we return is ignored or
669 * handled. That doesn't matter because its only purpose
670 * is to alert stop-signal processing code when another
671 * processor has come along and cleared the flag.
673 current->jobctl |= JOBCTL_STOP_DEQUEUED;
675 #ifdef CONFIG_POSIX_TIMERS
678 * Release the siglock to ensure proper locking order
679 * of timer locks outside of siglocks. Note, we leave
680 * irqs disabled here, since the posix-timers code is
681 * about to disable them again anyway.
683 spin_unlock(&tsk->sighand->siglock);
684 posixtimer_rearm(info);
685 spin_lock(&tsk->sighand->siglock);
687 /* Don't expose the si_sys_private value to userspace */
688 info->si_sys_private = 0;
693 EXPORT_SYMBOL_GPL(dequeue_signal);
695 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
697 struct task_struct *tsk = current;
698 struct sigpending *pending = &tsk->pending;
699 struct sigqueue *q, *sync = NULL;
702 * Might a synchronous signal be in the queue?
704 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
708 * Return the first synchronous signal in the queue.
710 list_for_each_entry(q, &pending->list, list) {
711 /* Synchronous signals have a postive si_code */
712 if ((q->info.si_code > SI_USER) &&
713 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
721 * Check if there is another siginfo for the same signal.
723 list_for_each_entry_continue(q, &pending->list, list) {
724 if (q->info.si_signo == sync->info.si_signo)
728 sigdelset(&pending->signal, sync->info.si_signo);
731 list_del_init(&sync->list);
732 copy_siginfo(info, &sync->info);
733 __sigqueue_free(sync);
734 return info->si_signo;
738 * Tell a process that it has a new active signal..
740 * NOTE! we rely on the previous spin_lock to
741 * lock interrupts for us! We can only be called with
742 * "siglock" held, and the local interrupt must
743 * have been disabled when that got acquired!
745 * No need to set need_resched since signal event passing
746 * goes through ->blocked
748 void signal_wake_up_state(struct task_struct *t, unsigned int state)
750 set_tsk_thread_flag(t, TIF_SIGPENDING);
752 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
753 * case. We don't check t->state here because there is a race with it
754 * executing another processor and just now entering stopped state.
755 * By using wake_up_state, we ensure the process will wake up and
756 * handle its death signal.
758 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
763 * Remove signals in mask from the pending set and queue.
764 * Returns 1 if any signals were found.
766 * All callers must be holding the siglock.
768 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
770 struct sigqueue *q, *n;
773 sigandsets(&m, mask, &s->signal);
774 if (sigisemptyset(&m))
777 sigandnsets(&s->signal, &s->signal, mask);
778 list_for_each_entry_safe(q, n, &s->list, list) {
779 if (sigismember(mask, q->info.si_signo)) {
780 list_del_init(&q->list);
786 static inline int is_si_special(const struct kernel_siginfo *info)
788 return info <= SEND_SIG_PRIV;
791 static inline bool si_fromuser(const struct kernel_siginfo *info)
793 return info == SEND_SIG_NOINFO ||
794 (!is_si_special(info) && SI_FROMUSER(info));
798 * called with RCU read lock from check_kill_permission()
800 static bool kill_ok_by_cred(struct task_struct *t)
802 const struct cred *cred = current_cred();
803 const struct cred *tcred = __task_cred(t);
805 return uid_eq(cred->euid, tcred->suid) ||
806 uid_eq(cred->euid, tcred->uid) ||
807 uid_eq(cred->uid, tcred->suid) ||
808 uid_eq(cred->uid, tcred->uid) ||
809 ns_capable(tcred->user_ns, CAP_KILL);
813 * Bad permissions for sending the signal
814 * - the caller must hold the RCU read lock
816 static int check_kill_permission(int sig, struct kernel_siginfo *info,
817 struct task_struct *t)
822 if (!valid_signal(sig))
825 if (!si_fromuser(info))
828 error = audit_signal_info(sig, t); /* Let audit system see the signal */
832 if (!same_thread_group(current, t) &&
833 !kill_ok_by_cred(t)) {
836 sid = task_session(t);
838 * We don't return the error if sid == NULL. The
839 * task was unhashed, the caller must notice this.
841 if (!sid || sid == task_session(current))
849 return security_task_kill(t, info, sig, NULL);
853 * ptrace_trap_notify - schedule trap to notify ptracer
854 * @t: tracee wanting to notify tracer
856 * This function schedules sticky ptrace trap which is cleared on the next
857 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
860 * If @t is running, STOP trap will be taken. If trapped for STOP and
861 * ptracer is listening for events, tracee is woken up so that it can
862 * re-trap for the new event. If trapped otherwise, STOP trap will be
863 * eventually taken without returning to userland after the existing traps
864 * are finished by PTRACE_CONT.
867 * Must be called with @task->sighand->siglock held.
869 static void ptrace_trap_notify(struct task_struct *t)
871 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
872 assert_spin_locked(&t->sighand->siglock);
874 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
875 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
879 * Handle magic process-wide effects of stop/continue signals. Unlike
880 * the signal actions, these happen immediately at signal-generation
881 * time regardless of blocking, ignoring, or handling. This does the
882 * actual continuing for SIGCONT, but not the actual stopping for stop
883 * signals. The process stop is done as a signal action for SIG_DFL.
885 * Returns true if the signal should be actually delivered, otherwise
886 * it should be dropped.
888 static bool prepare_signal(int sig, struct task_struct *p, bool force)
890 struct signal_struct *signal = p->signal;
891 struct task_struct *t;
894 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
895 if (!(signal->flags & SIGNAL_GROUP_EXIT))
896 return sig == SIGKILL;
898 * The process is in the middle of dying, nothing to do.
900 } else if (sig_kernel_stop(sig)) {
902 * This is a stop signal. Remove SIGCONT from all queues.
904 siginitset(&flush, sigmask(SIGCONT));
905 flush_sigqueue_mask(&flush, &signal->shared_pending);
906 for_each_thread(p, t)
907 flush_sigqueue_mask(&flush, &t->pending);
908 } else if (sig == SIGCONT) {
911 * Remove all stop signals from all queues, wake all threads.
913 siginitset(&flush, SIG_KERNEL_STOP_MASK);
914 flush_sigqueue_mask(&flush, &signal->shared_pending);
915 for_each_thread(p, t) {
916 flush_sigqueue_mask(&flush, &t->pending);
917 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
918 if (likely(!(t->ptrace & PT_SEIZED)))
919 wake_up_state(t, __TASK_STOPPED);
921 ptrace_trap_notify(t);
925 * Notify the parent with CLD_CONTINUED if we were stopped.
927 * If we were in the middle of a group stop, we pretend it
928 * was already finished, and then continued. Since SIGCHLD
929 * doesn't queue we report only CLD_STOPPED, as if the next
930 * CLD_CONTINUED was dropped.
933 if (signal->flags & SIGNAL_STOP_STOPPED)
934 why |= SIGNAL_CLD_CONTINUED;
935 else if (signal->group_stop_count)
936 why |= SIGNAL_CLD_STOPPED;
940 * The first thread which returns from do_signal_stop()
941 * will take ->siglock, notice SIGNAL_CLD_MASK, and
942 * notify its parent. See get_signal().
944 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
945 signal->group_stop_count = 0;
946 signal->group_exit_code = 0;
950 return !sig_ignored(p, sig, force);
954 * Test if P wants to take SIG. After we've checked all threads with this,
955 * it's equivalent to finding no threads not blocking SIG. Any threads not
956 * blocking SIG were ruled out because they are not running and already
957 * have pending signals. Such threads will dequeue from the shared queue
958 * as soon as they're available, so putting the signal on the shared queue
959 * will be equivalent to sending it to one such thread.
961 static inline bool wants_signal(int sig, struct task_struct *p)
963 if (sigismember(&p->blocked, sig))
966 if (p->flags & PF_EXITING)
972 if (task_is_stopped_or_traced(p))
975 return task_curr(p) || !signal_pending(p);
978 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
980 struct signal_struct *signal = p->signal;
981 struct task_struct *t;
984 * Now find a thread we can wake up to take the signal off the queue.
986 * If the main thread wants the signal, it gets first crack.
987 * Probably the least surprising to the average bear.
989 if (wants_signal(sig, p))
991 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
993 * There is just one thread and it does not need to be woken.
994 * It will dequeue unblocked signals before it runs again.
999 * Otherwise try to find a suitable thread.
1001 t = signal->curr_target;
1002 while (!wants_signal(sig, t)) {
1004 if (t == signal->curr_target)
1006 * No thread needs to be woken.
1007 * Any eligible threads will see
1008 * the signal in the queue soon.
1012 signal->curr_target = t;
1016 * Found a killable thread. If the signal will be fatal,
1017 * then start taking the whole group down immediately.
1019 if (sig_fatal(p, sig) &&
1020 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1021 !sigismember(&t->real_blocked, sig) &&
1022 (sig == SIGKILL || !p->ptrace)) {
1024 * This signal will be fatal to the whole group.
1026 if (!sig_kernel_coredump(sig)) {
1028 * Start a group exit and wake everybody up.
1029 * This way we don't have other threads
1030 * running and doing things after a slower
1031 * thread has the fatal signal pending.
1033 signal->flags = SIGNAL_GROUP_EXIT;
1034 signal->group_exit_code = sig;
1035 signal->group_stop_count = 0;
1038 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1039 sigaddset(&t->pending.signal, SIGKILL);
1040 signal_wake_up(t, 1);
1041 } while_each_thread(p, t);
1047 * The signal is already in the shared-pending queue.
1048 * Tell the chosen thread to wake up and dequeue it.
1050 signal_wake_up(t, sig == SIGKILL);
1054 static inline bool legacy_queue(struct sigpending *signals, int sig)
1056 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1059 #ifdef CONFIG_USER_NS
1060 static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t)
1062 if (current_user_ns() == task_cred_xxx(t, user_ns))
1065 if (SI_FROMKERNEL(info))
1069 info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
1070 make_kuid(current_user_ns(), info->si_uid));
1074 static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t)
1080 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1081 enum pid_type type, int from_ancestor_ns)
1083 struct sigpending *pending;
1085 int override_rlimit;
1086 int ret = 0, result;
1088 assert_spin_locked(&t->sighand->siglock);
1090 result = TRACE_SIGNAL_IGNORED;
1091 if (!prepare_signal(sig, t,
1092 from_ancestor_ns || (info == SEND_SIG_PRIV)))
1095 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1097 * Short-circuit ignored signals and support queuing
1098 * exactly one non-rt signal, so that we can get more
1099 * detailed information about the cause of the signal.
1101 result = TRACE_SIGNAL_ALREADY_PENDING;
1102 if (legacy_queue(pending, sig))
1105 result = TRACE_SIGNAL_DELIVERED;
1107 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1109 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1113 * Real-time signals must be queued if sent by sigqueue, or
1114 * some other real-time mechanism. It is implementation
1115 * defined whether kill() does so. We attempt to do so, on
1116 * the principle of least surprise, but since kill is not
1117 * allowed to fail with EAGAIN when low on memory we just
1118 * make sure at least one signal gets delivered and don't
1119 * pass on the info struct.
1122 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1124 override_rlimit = 0;
1126 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
1128 list_add_tail(&q->list, &pending->list);
1129 switch ((unsigned long) info) {
1130 case (unsigned long) SEND_SIG_NOINFO:
1131 clear_siginfo(&q->info);
1132 q->info.si_signo = sig;
1133 q->info.si_errno = 0;
1134 q->info.si_code = SI_USER;
1135 q->info.si_pid = task_tgid_nr_ns(current,
1136 task_active_pid_ns(t));
1137 q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1139 case (unsigned long) SEND_SIG_PRIV:
1140 clear_siginfo(&q->info);
1141 q->info.si_signo = sig;
1142 q->info.si_errno = 0;
1143 q->info.si_code = SI_KERNEL;
1148 copy_siginfo(&q->info, info);
1149 if (from_ancestor_ns)
1154 userns_fixup_signal_uid(&q->info, t);
1156 } else if (!is_si_special(info)) {
1157 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
1159 * Queue overflow, abort. We may abort if the
1160 * signal was rt and sent by user using something
1161 * other than kill().
1163 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1168 * This is a silent loss of information. We still
1169 * send the signal, but the *info bits are lost.
1171 result = TRACE_SIGNAL_LOSE_INFO;
1176 signalfd_notify(t, sig);
1177 sigaddset(&pending->signal, sig);
1179 /* Let multiprocess signals appear after on-going forks */
1180 if (type > PIDTYPE_TGID) {
1181 struct multiprocess_signals *delayed;
1182 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1183 sigset_t *signal = &delayed->signal;
1184 /* Can't queue both a stop and a continue signal */
1186 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1187 else if (sig_kernel_stop(sig))
1188 sigdelset(signal, SIGCONT);
1189 sigaddset(signal, sig);
1193 complete_signal(sig, t, type);
1195 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1199 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1202 int from_ancestor_ns = 0;
1204 #ifdef CONFIG_PID_NS
1205 from_ancestor_ns = si_fromuser(info) &&
1206 !task_pid_nr_ns(current, task_active_pid_ns(t));
1209 return __send_signal(sig, info, t, type, from_ancestor_ns);
1212 static void print_fatal_signal(int signr)
1214 struct pt_regs *regs = signal_pt_regs();
1215 pr_info("potentially unexpected fatal signal %d.\n", signr);
1217 #if defined(__i386__) && !defined(__arch_um__)
1218 pr_info("code at %08lx: ", regs->ip);
1221 for (i = 0; i < 16; i++) {
1224 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1226 pr_cont("%02x ", insn);
1236 static int __init setup_print_fatal_signals(char *str)
1238 get_option (&str, &print_fatal_signals);
1243 __setup("print-fatal-signals=", setup_print_fatal_signals);
1246 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1248 return send_signal(sig, info, p, PIDTYPE_TGID);
1251 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1254 unsigned long flags;
1257 if (lock_task_sighand(p, &flags)) {
1258 ret = send_signal(sig, info, p, type);
1259 unlock_task_sighand(p, &flags);
1266 * Force a signal that the process can't ignore: if necessary
1267 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1269 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1270 * since we do not want to have a signal handler that was blocked
1271 * be invoked when user space had explicitly blocked it.
1273 * We don't want to have recursive SIGSEGV's etc, for example,
1274 * that is why we also clear SIGNAL_UNKILLABLE.
1277 force_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *t)
1279 unsigned long int flags;
1280 int ret, blocked, ignored;
1281 struct k_sigaction *action;
1283 spin_lock_irqsave(&t->sighand->siglock, flags);
1284 action = &t->sighand->action[sig-1];
1285 ignored = action->sa.sa_handler == SIG_IGN;
1286 blocked = sigismember(&t->blocked, sig);
1287 if (blocked || ignored) {
1288 action->sa.sa_handler = SIG_DFL;
1290 sigdelset(&t->blocked, sig);
1291 recalc_sigpending_and_wake(t);
1295 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1296 * debugging to leave init killable.
1298 if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
1299 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1300 ret = send_signal(sig, info, t, PIDTYPE_PID);
1301 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1307 * Nuke all other threads in the group.
1309 int zap_other_threads(struct task_struct *p)
1311 struct task_struct *t = p;
1314 p->signal->group_stop_count = 0;
1316 while_each_thread(p, t) {
1317 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1320 /* Don't bother with already dead threads */
1323 sigaddset(&t->pending.signal, SIGKILL);
1324 signal_wake_up(t, 1);
1330 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1331 unsigned long *flags)
1333 struct sighand_struct *sighand;
1337 sighand = rcu_dereference(tsk->sighand);
1338 if (unlikely(sighand == NULL))
1342 * This sighand can be already freed and even reused, but
1343 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1344 * initializes ->siglock: this slab can't go away, it has
1345 * the same object type, ->siglock can't be reinitialized.
1347 * We need to ensure that tsk->sighand is still the same
1348 * after we take the lock, we can race with de_thread() or
1349 * __exit_signal(). In the latter case the next iteration
1350 * must see ->sighand == NULL.
1352 spin_lock_irqsave(&sighand->siglock, *flags);
1353 if (likely(sighand == tsk->sighand))
1355 spin_unlock_irqrestore(&sighand->siglock, *flags);
1363 * send signal info to all the members of a group
1365 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1366 struct task_struct *p, enum pid_type type)
1371 ret = check_kill_permission(sig, info, p);
1375 ret = do_send_sig_info(sig, info, p, type);
1381 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1382 * control characters do (^C, ^Z etc)
1383 * - the caller must hold at least a readlock on tasklist_lock
1385 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1387 struct task_struct *p = NULL;
1388 int retval, success;
1392 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1393 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1396 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1397 return success ? 0 : retval;
1400 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1403 struct task_struct *p;
1407 p = pid_task(pid, PIDTYPE_PID);
1409 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1411 if (likely(!p || error != -ESRCH))
1415 * The task was unhashed in between, try again. If it
1416 * is dead, pid_task() will return NULL, if we race with
1417 * de_thread() it will find the new leader.
1422 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1426 error = kill_pid_info(sig, info, find_vpid(pid));
1431 static inline bool kill_as_cred_perm(const struct cred *cred,
1432 struct task_struct *target)
1434 const struct cred *pcred = __task_cred(target);
1436 return uid_eq(cred->euid, pcred->suid) ||
1437 uid_eq(cred->euid, pcred->uid) ||
1438 uid_eq(cred->uid, pcred->suid) ||
1439 uid_eq(cred->uid, pcred->uid);
1442 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1443 int kill_pid_info_as_cred(int sig, struct kernel_siginfo *info, struct pid *pid,
1444 const struct cred *cred)
1447 struct task_struct *p;
1448 unsigned long flags;
1450 if (!valid_signal(sig))
1454 p = pid_task(pid, PIDTYPE_PID);
1459 if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
1463 ret = security_task_kill(p, info, sig, cred);
1468 if (lock_task_sighand(p, &flags)) {
1469 ret = __send_signal(sig, info, p, PIDTYPE_TGID, 0);
1470 unlock_task_sighand(p, &flags);
1478 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
1481 * kill_something_info() interprets pid in interesting ways just like kill(2).
1483 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1484 * is probably wrong. Should make it like BSD or SYSV.
1487 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1493 ret = kill_pid_info(sig, info, find_vpid(pid));
1498 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1502 read_lock(&tasklist_lock);
1504 ret = __kill_pgrp_info(sig, info,
1505 pid ? find_vpid(-pid) : task_pgrp(current));
1507 int retval = 0, count = 0;
1508 struct task_struct * p;
1510 for_each_process(p) {
1511 if (task_pid_vnr(p) > 1 &&
1512 !same_thread_group(p, current)) {
1513 int err = group_send_sig_info(sig, info, p,
1520 ret = count ? retval : -ESRCH;
1522 read_unlock(&tasklist_lock);
1528 * These are for backward compatibility with the rest of the kernel source.
1531 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1534 * Make sure legacy kernel users don't send in bad values
1535 * (normal paths check this in check_kill_permission).
1537 if (!valid_signal(sig))
1540 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1542 EXPORT_SYMBOL(send_sig_info);
1544 #define __si_special(priv) \
1545 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1548 send_sig(int sig, struct task_struct *p, int priv)
1550 return send_sig_info(sig, __si_special(priv), p);
1552 EXPORT_SYMBOL(send_sig);
1554 void force_sig(int sig, struct task_struct *p)
1556 force_sig_info(sig, SEND_SIG_PRIV, p);
1558 EXPORT_SYMBOL(force_sig);
1561 * When things go south during signal handling, we
1562 * will force a SIGSEGV. And if the signal that caused
1563 * the problem was already a SIGSEGV, we'll want to
1564 * make sure we don't even try to deliver the signal..
1566 void force_sigsegv(int sig, struct task_struct *p)
1568 if (sig == SIGSEGV) {
1569 unsigned long flags;
1570 spin_lock_irqsave(&p->sighand->siglock, flags);
1571 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1572 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1574 force_sig(SIGSEGV, p);
1577 int force_sig_fault(int sig, int code, void __user *addr
1578 ___ARCH_SI_TRAPNO(int trapno)
1579 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1580 , struct task_struct *t)
1582 struct kernel_siginfo info;
1584 clear_siginfo(&info);
1585 info.si_signo = sig;
1587 info.si_code = code;
1588 info.si_addr = addr;
1589 #ifdef __ARCH_SI_TRAPNO
1590 info.si_trapno = trapno;
1594 info.si_flags = flags;
1597 return force_sig_info(info.si_signo, &info, t);
1600 int send_sig_fault(int sig, int code, void __user *addr
1601 ___ARCH_SI_TRAPNO(int trapno)
1602 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1603 , struct task_struct *t)
1605 struct kernel_siginfo info;
1607 clear_siginfo(&info);
1608 info.si_signo = sig;
1610 info.si_code = code;
1611 info.si_addr = addr;
1612 #ifdef __ARCH_SI_TRAPNO
1613 info.si_trapno = trapno;
1617 info.si_flags = flags;
1620 return send_sig_info(info.si_signo, &info, t);
1623 int force_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1625 struct kernel_siginfo info;
1627 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1628 clear_siginfo(&info);
1629 info.si_signo = SIGBUS;
1631 info.si_code = code;
1632 info.si_addr = addr;
1633 info.si_addr_lsb = lsb;
1634 return force_sig_info(info.si_signo, &info, t);
1637 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1639 struct kernel_siginfo info;
1641 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1642 clear_siginfo(&info);
1643 info.si_signo = SIGBUS;
1645 info.si_code = code;
1646 info.si_addr = addr;
1647 info.si_addr_lsb = lsb;
1648 return send_sig_info(info.si_signo, &info, t);
1650 EXPORT_SYMBOL(send_sig_mceerr);
1652 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1654 struct kernel_siginfo info;
1656 clear_siginfo(&info);
1657 info.si_signo = SIGSEGV;
1659 info.si_code = SEGV_BNDERR;
1660 info.si_addr = addr;
1661 info.si_lower = lower;
1662 info.si_upper = upper;
1663 return force_sig_info(info.si_signo, &info, current);
1667 int force_sig_pkuerr(void __user *addr, u32 pkey)
1669 struct kernel_siginfo info;
1671 clear_siginfo(&info);
1672 info.si_signo = SIGSEGV;
1674 info.si_code = SEGV_PKUERR;
1675 info.si_addr = addr;
1676 info.si_pkey = pkey;
1677 return force_sig_info(info.si_signo, &info, current);
1681 /* For the crazy architectures that include trap information in
1682 * the errno field, instead of an actual errno value.
1684 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1686 struct kernel_siginfo info;
1688 clear_siginfo(&info);
1689 info.si_signo = SIGTRAP;
1690 info.si_errno = errno;
1691 info.si_code = TRAP_HWBKPT;
1692 info.si_addr = addr;
1693 return force_sig_info(info.si_signo, &info, current);
1696 int kill_pgrp(struct pid *pid, int sig, int priv)
1700 read_lock(&tasklist_lock);
1701 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1702 read_unlock(&tasklist_lock);
1706 EXPORT_SYMBOL(kill_pgrp);
1708 int kill_pid(struct pid *pid, int sig, int priv)
1710 return kill_pid_info(sig, __si_special(priv), pid);
1712 EXPORT_SYMBOL(kill_pid);
1715 * These functions support sending signals using preallocated sigqueue
1716 * structures. This is needed "because realtime applications cannot
1717 * afford to lose notifications of asynchronous events, like timer
1718 * expirations or I/O completions". In the case of POSIX Timers
1719 * we allocate the sigqueue structure from the timer_create. If this
1720 * allocation fails we are able to report the failure to the application
1721 * with an EAGAIN error.
1723 struct sigqueue *sigqueue_alloc(void)
1725 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1728 q->flags |= SIGQUEUE_PREALLOC;
1733 void sigqueue_free(struct sigqueue *q)
1735 unsigned long flags;
1736 spinlock_t *lock = ¤t->sighand->siglock;
1738 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1740 * We must hold ->siglock while testing q->list
1741 * to serialize with collect_signal() or with
1742 * __exit_signal()->flush_sigqueue().
1744 spin_lock_irqsave(lock, flags);
1745 q->flags &= ~SIGQUEUE_PREALLOC;
1747 * If it is queued it will be freed when dequeued,
1748 * like the "regular" sigqueue.
1750 if (!list_empty(&q->list))
1752 spin_unlock_irqrestore(lock, flags);
1758 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1760 int sig = q->info.si_signo;
1761 struct sigpending *pending;
1762 struct task_struct *t;
1763 unsigned long flags;
1766 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1770 t = pid_task(pid, type);
1771 if (!t || !likely(lock_task_sighand(t, &flags)))
1774 ret = 1; /* the signal is ignored */
1775 result = TRACE_SIGNAL_IGNORED;
1776 if (!prepare_signal(sig, t, false))
1780 if (unlikely(!list_empty(&q->list))) {
1782 * If an SI_TIMER entry is already queue just increment
1783 * the overrun count.
1785 BUG_ON(q->info.si_code != SI_TIMER);
1786 q->info.si_overrun++;
1787 result = TRACE_SIGNAL_ALREADY_PENDING;
1790 q->info.si_overrun = 0;
1792 signalfd_notify(t, sig);
1793 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1794 list_add_tail(&q->list, &pending->list);
1795 sigaddset(&pending->signal, sig);
1796 complete_signal(sig, t, type);
1797 result = TRACE_SIGNAL_DELIVERED;
1799 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
1800 unlock_task_sighand(t, &flags);
1807 * Let a parent know about the death of a child.
1808 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1810 * Returns true if our parent ignored us and so we've switched to
1813 bool do_notify_parent(struct task_struct *tsk, int sig)
1815 struct kernel_siginfo info;
1816 unsigned long flags;
1817 struct sighand_struct *psig;
1818 bool autoreap = false;
1823 /* do_notify_parent_cldstop should have been called instead. */
1824 BUG_ON(task_is_stopped_or_traced(tsk));
1826 BUG_ON(!tsk->ptrace &&
1827 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1829 if (sig != SIGCHLD) {
1831 * This is only possible if parent == real_parent.
1832 * Check if it has changed security domain.
1834 if (tsk->parent_exec_id != tsk->parent->self_exec_id)
1838 clear_siginfo(&info);
1839 info.si_signo = sig;
1842 * We are under tasklist_lock here so our parent is tied to
1843 * us and cannot change.
1845 * task_active_pid_ns will always return the same pid namespace
1846 * until a task passes through release_task.
1848 * write_lock() currently calls preempt_disable() which is the
1849 * same as rcu_read_lock(), but according to Oleg, this is not
1850 * correct to rely on this
1853 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1854 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1858 task_cputime(tsk, &utime, &stime);
1859 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
1860 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
1862 info.si_status = tsk->exit_code & 0x7f;
1863 if (tsk->exit_code & 0x80)
1864 info.si_code = CLD_DUMPED;
1865 else if (tsk->exit_code & 0x7f)
1866 info.si_code = CLD_KILLED;
1868 info.si_code = CLD_EXITED;
1869 info.si_status = tsk->exit_code >> 8;
1872 psig = tsk->parent->sighand;
1873 spin_lock_irqsave(&psig->siglock, flags);
1874 if (!tsk->ptrace && sig == SIGCHLD &&
1875 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1876 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1878 * We are exiting and our parent doesn't care. POSIX.1
1879 * defines special semantics for setting SIGCHLD to SIG_IGN
1880 * or setting the SA_NOCLDWAIT flag: we should be reaped
1881 * automatically and not left for our parent's wait4 call.
1882 * Rather than having the parent do it as a magic kind of
1883 * signal handler, we just set this to tell do_exit that we
1884 * can be cleaned up without becoming a zombie. Note that
1885 * we still call __wake_up_parent in this case, because a
1886 * blocked sys_wait4 might now return -ECHILD.
1888 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1889 * is implementation-defined: we do (if you don't want
1890 * it, just use SIG_IGN instead).
1893 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1896 if (valid_signal(sig) && sig)
1897 __group_send_sig_info(sig, &info, tsk->parent);
1898 __wake_up_parent(tsk, tsk->parent);
1899 spin_unlock_irqrestore(&psig->siglock, flags);
1905 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1906 * @tsk: task reporting the state change
1907 * @for_ptracer: the notification is for ptracer
1908 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1910 * Notify @tsk's parent that the stopped/continued state has changed. If
1911 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1912 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1915 * Must be called with tasklist_lock at least read locked.
1917 static void do_notify_parent_cldstop(struct task_struct *tsk,
1918 bool for_ptracer, int why)
1920 struct kernel_siginfo info;
1921 unsigned long flags;
1922 struct task_struct *parent;
1923 struct sighand_struct *sighand;
1927 parent = tsk->parent;
1929 tsk = tsk->group_leader;
1930 parent = tsk->real_parent;
1933 clear_siginfo(&info);
1934 info.si_signo = SIGCHLD;
1937 * see comment in do_notify_parent() about the following 4 lines
1940 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
1941 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
1944 task_cputime(tsk, &utime, &stime);
1945 info.si_utime = nsec_to_clock_t(utime);
1946 info.si_stime = nsec_to_clock_t(stime);
1951 info.si_status = SIGCONT;
1954 info.si_status = tsk->signal->group_exit_code & 0x7f;
1957 info.si_status = tsk->exit_code & 0x7f;
1963 sighand = parent->sighand;
1964 spin_lock_irqsave(&sighand->siglock, flags);
1965 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1966 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1967 __group_send_sig_info(SIGCHLD, &info, parent);
1969 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1971 __wake_up_parent(tsk, parent);
1972 spin_unlock_irqrestore(&sighand->siglock, flags);
1975 static inline bool may_ptrace_stop(void)
1977 if (!likely(current->ptrace))
1980 * Are we in the middle of do_coredump?
1981 * If so and our tracer is also part of the coredump stopping
1982 * is a deadlock situation, and pointless because our tracer
1983 * is dead so don't allow us to stop.
1984 * If SIGKILL was already sent before the caller unlocked
1985 * ->siglock we must see ->core_state != NULL. Otherwise it
1986 * is safe to enter schedule().
1988 * This is almost outdated, a task with the pending SIGKILL can't
1989 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1990 * after SIGKILL was already dequeued.
1992 if (unlikely(current->mm->core_state) &&
1993 unlikely(current->mm == current->parent->mm))
2000 * Return non-zero if there is a SIGKILL that should be waking us up.
2001 * Called with the siglock held.
2003 static bool sigkill_pending(struct task_struct *tsk)
2005 return sigismember(&tsk->pending.signal, SIGKILL) ||
2006 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
2010 * This must be called with current->sighand->siglock held.
2012 * This should be the path for all ptrace stops.
2013 * We always set current->last_siginfo while stopped here.
2014 * That makes it a way to test a stopped process for
2015 * being ptrace-stopped vs being job-control-stopped.
2017 * If we actually decide not to stop at all because the tracer
2018 * is gone, we keep current->exit_code unless clear_code.
2020 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2021 __releases(¤t->sighand->siglock)
2022 __acquires(¤t->sighand->siglock)
2024 bool gstop_done = false;
2026 if (arch_ptrace_stop_needed(exit_code, info)) {
2028 * The arch code has something special to do before a
2029 * ptrace stop. This is allowed to block, e.g. for faults
2030 * on user stack pages. We can't keep the siglock while
2031 * calling arch_ptrace_stop, so we must release it now.
2032 * To preserve proper semantics, we must do this before
2033 * any signal bookkeeping like checking group_stop_count.
2034 * Meanwhile, a SIGKILL could come in before we retake the
2035 * siglock. That must prevent us from sleeping in TASK_TRACED.
2036 * So after regaining the lock, we must check for SIGKILL.
2038 spin_unlock_irq(¤t->sighand->siglock);
2039 arch_ptrace_stop(exit_code, info);
2040 spin_lock_irq(¤t->sighand->siglock);
2041 if (sigkill_pending(current))
2045 set_special_state(TASK_TRACED);
2048 * We're committing to trapping. TRACED should be visible before
2049 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2050 * Also, transition to TRACED and updates to ->jobctl should be
2051 * atomic with respect to siglock and should be done after the arch
2052 * hook as siglock is released and regrabbed across it.
2057 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2059 * set_current_state() smp_wmb();
2061 * wait_task_stopped()
2062 * task_stopped_code()
2063 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2067 current->last_siginfo = info;
2068 current->exit_code = exit_code;
2071 * If @why is CLD_STOPPED, we're trapping to participate in a group
2072 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2073 * across siglock relocks since INTERRUPT was scheduled, PENDING
2074 * could be clear now. We act as if SIGCONT is received after
2075 * TASK_TRACED is entered - ignore it.
2077 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2078 gstop_done = task_participate_group_stop(current);
2080 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2081 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2082 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2083 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2085 /* entering a trap, clear TRAPPING */
2086 task_clear_jobctl_trapping(current);
2088 spin_unlock_irq(¤t->sighand->siglock);
2089 read_lock(&tasklist_lock);
2090 if (may_ptrace_stop()) {
2092 * Notify parents of the stop.
2094 * While ptraced, there are two parents - the ptracer and
2095 * the real_parent of the group_leader. The ptracer should
2096 * know about every stop while the real parent is only
2097 * interested in the completion of group stop. The states
2098 * for the two don't interact with each other. Notify
2099 * separately unless they're gonna be duplicates.
2101 do_notify_parent_cldstop(current, true, why);
2102 if (gstop_done && ptrace_reparented(current))
2103 do_notify_parent_cldstop(current, false, why);
2106 * Don't want to allow preemption here, because
2107 * sys_ptrace() needs this task to be inactive.
2109 * XXX: implement read_unlock_no_resched().
2112 read_unlock(&tasklist_lock);
2113 preempt_enable_no_resched();
2114 cgroup_enter_frozen();
2115 freezable_schedule();
2116 cgroup_leave_frozen(true);
2119 * By the time we got the lock, our tracer went away.
2120 * Don't drop the lock yet, another tracer may come.
2122 * If @gstop_done, the ptracer went away between group stop
2123 * completion and here. During detach, it would have set
2124 * JOBCTL_STOP_PENDING on us and we'll re-enter
2125 * TASK_STOPPED in do_signal_stop() on return, so notifying
2126 * the real parent of the group stop completion is enough.
2129 do_notify_parent_cldstop(current, false, why);
2131 /* tasklist protects us from ptrace_freeze_traced() */
2132 __set_current_state(TASK_RUNNING);
2134 current->exit_code = 0;
2135 read_unlock(&tasklist_lock);
2139 * We are back. Now reacquire the siglock before touching
2140 * last_siginfo, so that we are sure to have synchronized with
2141 * any signal-sending on another CPU that wants to examine it.
2143 spin_lock_irq(¤t->sighand->siglock);
2144 current->last_siginfo = NULL;
2146 /* LISTENING can be set only during STOP traps, clear it */
2147 current->jobctl &= ~JOBCTL_LISTENING;
2150 * Queued signals ignored us while we were stopped for tracing.
2151 * So check for any that we should take before resuming user mode.
2152 * This sets TIF_SIGPENDING, but never clears it.
2154 recalc_sigpending_tsk(current);
2157 static void ptrace_do_notify(int signr, int exit_code, int why)
2159 kernel_siginfo_t info;
2161 clear_siginfo(&info);
2162 info.si_signo = signr;
2163 info.si_code = exit_code;
2164 info.si_pid = task_pid_vnr(current);
2165 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2167 /* Let the debugger run. */
2168 ptrace_stop(exit_code, why, 1, &info);
2171 void ptrace_notify(int exit_code)
2173 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2174 if (unlikely(current->task_works))
2177 spin_lock_irq(¤t->sighand->siglock);
2178 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2179 spin_unlock_irq(¤t->sighand->siglock);
2183 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2184 * @signr: signr causing group stop if initiating
2186 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2187 * and participate in it. If already set, participate in the existing
2188 * group stop. If participated in a group stop (and thus slept), %true is
2189 * returned with siglock released.
2191 * If ptraced, this function doesn't handle stop itself. Instead,
2192 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2193 * untouched. The caller must ensure that INTERRUPT trap handling takes
2194 * places afterwards.
2197 * Must be called with @current->sighand->siglock held, which is released
2201 * %false if group stop is already cancelled or ptrace trap is scheduled.
2202 * %true if participated in group stop.
2204 static bool do_signal_stop(int signr)
2205 __releases(¤t->sighand->siglock)
2207 struct signal_struct *sig = current->signal;
2209 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2210 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2211 struct task_struct *t;
2213 /* signr will be recorded in task->jobctl for retries */
2214 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2216 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2217 unlikely(signal_group_exit(sig)))
2220 * There is no group stop already in progress. We must
2223 * While ptraced, a task may be resumed while group stop is
2224 * still in effect and then receive a stop signal and
2225 * initiate another group stop. This deviates from the
2226 * usual behavior as two consecutive stop signals can't
2227 * cause two group stops when !ptraced. That is why we
2228 * also check !task_is_stopped(t) below.
2230 * The condition can be distinguished by testing whether
2231 * SIGNAL_STOP_STOPPED is already set. Don't generate
2232 * group_exit_code in such case.
2234 * This is not necessary for SIGNAL_STOP_CONTINUED because
2235 * an intervening stop signal is required to cause two
2236 * continued events regardless of ptrace.
2238 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2239 sig->group_exit_code = signr;
2241 sig->group_stop_count = 0;
2243 if (task_set_jobctl_pending(current, signr | gstop))
2244 sig->group_stop_count++;
2247 while_each_thread(current, t) {
2249 * Setting state to TASK_STOPPED for a group
2250 * stop is always done with the siglock held,
2251 * so this check has no races.
2253 if (!task_is_stopped(t) &&
2254 task_set_jobctl_pending(t, signr | gstop)) {
2255 sig->group_stop_count++;
2256 if (likely(!(t->ptrace & PT_SEIZED)))
2257 signal_wake_up(t, 0);
2259 ptrace_trap_notify(t);
2264 if (likely(!current->ptrace)) {
2268 * If there are no other threads in the group, or if there
2269 * is a group stop in progress and we are the last to stop,
2270 * report to the parent.
2272 if (task_participate_group_stop(current))
2273 notify = CLD_STOPPED;
2275 set_special_state(TASK_STOPPED);
2276 spin_unlock_irq(¤t->sighand->siglock);
2279 * Notify the parent of the group stop completion. Because
2280 * we're not holding either the siglock or tasklist_lock
2281 * here, ptracer may attach inbetween; however, this is for
2282 * group stop and should always be delivered to the real
2283 * parent of the group leader. The new ptracer will get
2284 * its notification when this task transitions into
2288 read_lock(&tasklist_lock);
2289 do_notify_parent_cldstop(current, false, notify);
2290 read_unlock(&tasklist_lock);
2293 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2294 cgroup_enter_frozen();
2295 freezable_schedule();
2299 * While ptraced, group stop is handled by STOP trap.
2300 * Schedule it and let the caller deal with it.
2302 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2308 * do_jobctl_trap - take care of ptrace jobctl traps
2310 * When PT_SEIZED, it's used for both group stop and explicit
2311 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2312 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2313 * the stop signal; otherwise, %SIGTRAP.
2315 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2316 * number as exit_code and no siginfo.
2319 * Must be called with @current->sighand->siglock held, which may be
2320 * released and re-acquired before returning with intervening sleep.
2322 static void do_jobctl_trap(void)
2324 struct signal_struct *signal = current->signal;
2325 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2327 if (current->ptrace & PT_SEIZED) {
2328 if (!signal->group_stop_count &&
2329 !(signal->flags & SIGNAL_STOP_STOPPED))
2331 WARN_ON_ONCE(!signr);
2332 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2335 WARN_ON_ONCE(!signr);
2336 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2337 current->exit_code = 0;
2342 * do_freezer_trap - handle the freezer jobctl trap
2344 * Puts the task into frozen state, if only the task is not about to quit.
2345 * In this case it drops JOBCTL_TRAP_FREEZE.
2348 * Must be called with @current->sighand->siglock held,
2349 * which is always released before returning.
2351 static void do_freezer_trap(void)
2352 __releases(¤t->sighand->siglock)
2355 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2356 * let's make another loop to give it a chance to be handled.
2357 * In any case, we'll return back.
2359 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2360 JOBCTL_TRAP_FREEZE) {
2361 spin_unlock_irq(¤t->sighand->siglock);
2366 * Now we're sure that there is no pending fatal signal and no
2367 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2368 * immediately (if there is a non-fatal signal pending), and
2369 * put the task into sleep.
2371 __set_current_state(TASK_INTERRUPTIBLE);
2372 clear_thread_flag(TIF_SIGPENDING);
2373 spin_unlock_irq(¤t->sighand->siglock);
2374 cgroup_enter_frozen();
2375 freezable_schedule();
2378 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2381 * We do not check sig_kernel_stop(signr) but set this marker
2382 * unconditionally because we do not know whether debugger will
2383 * change signr. This flag has no meaning unless we are going
2384 * to stop after return from ptrace_stop(). In this case it will
2385 * be checked in do_signal_stop(), we should only stop if it was
2386 * not cleared by SIGCONT while we were sleeping. See also the
2387 * comment in dequeue_signal().
2389 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2390 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2392 /* We're back. Did the debugger cancel the sig? */
2393 signr = current->exit_code;
2397 current->exit_code = 0;
2400 * Update the siginfo structure if the signal has
2401 * changed. If the debugger wanted something
2402 * specific in the siginfo structure then it should
2403 * have updated *info via PTRACE_SETSIGINFO.
2405 if (signr != info->si_signo) {
2406 clear_siginfo(info);
2407 info->si_signo = signr;
2409 info->si_code = SI_USER;
2411 info->si_pid = task_pid_vnr(current->parent);
2412 info->si_uid = from_kuid_munged(current_user_ns(),
2413 task_uid(current->parent));
2417 /* If the (new) signal is now blocked, requeue it. */
2418 if (sigismember(¤t->blocked, signr)) {
2419 send_signal(signr, info, current, PIDTYPE_PID);
2426 bool get_signal(struct ksignal *ksig)
2428 struct sighand_struct *sighand = current->sighand;
2429 struct signal_struct *signal = current->signal;
2432 if (unlikely(current->task_works))
2435 if (unlikely(uprobe_deny_signal()))
2439 * Do this once, we can't return to user-mode if freezing() == T.
2440 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2441 * thus do not need another check after return.
2446 spin_lock_irq(&sighand->siglock);
2448 * Every stopped thread goes here after wakeup. Check to see if
2449 * we should notify the parent, prepare_signal(SIGCONT) encodes
2450 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2452 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2455 if (signal->flags & SIGNAL_CLD_CONTINUED)
2456 why = CLD_CONTINUED;
2460 signal->flags &= ~SIGNAL_CLD_MASK;
2462 spin_unlock_irq(&sighand->siglock);
2465 * Notify the parent that we're continuing. This event is
2466 * always per-process and doesn't make whole lot of sense
2467 * for ptracers, who shouldn't consume the state via
2468 * wait(2) either, but, for backward compatibility, notify
2469 * the ptracer of the group leader too unless it's gonna be
2472 read_lock(&tasklist_lock);
2473 do_notify_parent_cldstop(current, false, why);
2475 if (ptrace_reparented(current->group_leader))
2476 do_notify_parent_cldstop(current->group_leader,
2478 read_unlock(&tasklist_lock);
2483 /* Has this task already been marked for death? */
2484 if (signal_group_exit(signal)) {
2485 ksig->info.si_signo = signr = SIGKILL;
2486 sigdelset(¤t->pending.signal, SIGKILL);
2487 recalc_sigpending();
2492 struct k_sigaction *ka;
2494 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2498 if (unlikely(current->jobctl &
2499 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2500 if (current->jobctl & JOBCTL_TRAP_MASK) {
2502 spin_unlock_irq(&sighand->siglock);
2503 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2510 * If the task is leaving the frozen state, let's update
2511 * cgroup counters and reset the frozen bit.
2513 if (unlikely(cgroup_task_frozen(current))) {
2514 spin_unlock_irq(&sighand->siglock);
2515 cgroup_leave_frozen(false);
2520 * Signals generated by the execution of an instruction
2521 * need to be delivered before any other pending signals
2522 * so that the instruction pointer in the signal stack
2523 * frame points to the faulting instruction.
2525 signr = dequeue_synchronous_signal(&ksig->info);
2527 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2530 break; /* will return 0 */
2532 if (unlikely(current->ptrace) && signr != SIGKILL) {
2533 signr = ptrace_signal(signr, &ksig->info);
2538 ka = &sighand->action[signr-1];
2540 /* Trace actually delivered signals. */
2541 trace_signal_deliver(signr, &ksig->info, ka);
2543 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2545 if (ka->sa.sa_handler != SIG_DFL) {
2546 /* Run the handler. */
2549 if (ka->sa.sa_flags & SA_ONESHOT)
2550 ka->sa.sa_handler = SIG_DFL;
2552 break; /* will return non-zero "signr" value */
2556 * Now we are doing the default action for this signal.
2558 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2562 * Global init gets no signals it doesn't want.
2563 * Container-init gets no signals it doesn't want from same
2566 * Note that if global/container-init sees a sig_kernel_only()
2567 * signal here, the signal must have been generated internally
2568 * or must have come from an ancestor namespace. In either
2569 * case, the signal cannot be dropped.
2571 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2572 !sig_kernel_only(signr))
2575 if (sig_kernel_stop(signr)) {
2577 * The default action is to stop all threads in
2578 * the thread group. The job control signals
2579 * do nothing in an orphaned pgrp, but SIGSTOP
2580 * always works. Note that siglock needs to be
2581 * dropped during the call to is_orphaned_pgrp()
2582 * because of lock ordering with tasklist_lock.
2583 * This allows an intervening SIGCONT to be posted.
2584 * We need to check for that and bail out if necessary.
2586 if (signr != SIGSTOP) {
2587 spin_unlock_irq(&sighand->siglock);
2589 /* signals can be posted during this window */
2591 if (is_current_pgrp_orphaned())
2594 spin_lock_irq(&sighand->siglock);
2597 if (likely(do_signal_stop(ksig->info.si_signo))) {
2598 /* It released the siglock. */
2603 * We didn't actually stop, due to a race
2604 * with SIGCONT or something like that.
2610 spin_unlock_irq(&sighand->siglock);
2611 if (unlikely(cgroup_task_frozen(current)))
2612 cgroup_leave_frozen(true);
2615 * Anything else is fatal, maybe with a core dump.
2617 current->flags |= PF_SIGNALED;
2619 if (sig_kernel_coredump(signr)) {
2620 if (print_fatal_signals)
2621 print_fatal_signal(ksig->info.si_signo);
2622 proc_coredump_connector(current);
2624 * If it was able to dump core, this kills all
2625 * other threads in the group and synchronizes with
2626 * their demise. If we lost the race with another
2627 * thread getting here, it set group_exit_code
2628 * first and our do_group_exit call below will use
2629 * that value and ignore the one we pass it.
2631 do_coredump(&ksig->info);
2635 * Death signals, no core dump.
2637 do_group_exit(ksig->info.si_signo);
2640 spin_unlock_irq(&sighand->siglock);
2643 return ksig->sig > 0;
2647 * signal_delivered -
2648 * @ksig: kernel signal struct
2649 * @stepping: nonzero if debugger single-step or block-step in use
2651 * This function should be called when a signal has successfully been
2652 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2653 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2654 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2656 static void signal_delivered(struct ksignal *ksig, int stepping)
2660 /* A signal was successfully delivered, and the
2661 saved sigmask was stored on the signal frame,
2662 and will be restored by sigreturn. So we can
2663 simply clear the restore sigmask flag. */
2664 clear_restore_sigmask();
2666 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2667 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2668 sigaddset(&blocked, ksig->sig);
2669 set_current_blocked(&blocked);
2670 tracehook_signal_handler(stepping);
2673 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2676 force_sigsegv(ksig->sig, current);
2678 signal_delivered(ksig, stepping);
2682 * It could be that complete_signal() picked us to notify about the
2683 * group-wide signal. Other threads should be notified now to take
2684 * the shared signals in @which since we will not.
2686 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2689 struct task_struct *t;
2691 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2692 if (sigisemptyset(&retarget))
2696 while_each_thread(tsk, t) {
2697 if (t->flags & PF_EXITING)
2700 if (!has_pending_signals(&retarget, &t->blocked))
2702 /* Remove the signals this thread can handle. */
2703 sigandsets(&retarget, &retarget, &t->blocked);
2705 if (!signal_pending(t))
2706 signal_wake_up(t, 0);
2708 if (sigisemptyset(&retarget))
2713 void exit_signals(struct task_struct *tsk)
2719 * @tsk is about to have PF_EXITING set - lock out users which
2720 * expect stable threadgroup.
2722 cgroup_threadgroup_change_begin(tsk);
2724 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2725 tsk->flags |= PF_EXITING;
2726 cgroup_threadgroup_change_end(tsk);
2730 spin_lock_irq(&tsk->sighand->siglock);
2732 * From now this task is not visible for group-wide signals,
2733 * see wants_signal(), do_signal_stop().
2735 tsk->flags |= PF_EXITING;
2737 cgroup_threadgroup_change_end(tsk);
2739 if (!signal_pending(tsk))
2742 unblocked = tsk->blocked;
2743 signotset(&unblocked);
2744 retarget_shared_pending(tsk, &unblocked);
2746 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2747 task_participate_group_stop(tsk))
2748 group_stop = CLD_STOPPED;
2750 spin_unlock_irq(&tsk->sighand->siglock);
2753 * If group stop has completed, deliver the notification. This
2754 * should always go to the real parent of the group leader.
2756 if (unlikely(group_stop)) {
2757 read_lock(&tasklist_lock);
2758 do_notify_parent_cldstop(tsk, false, group_stop);
2759 read_unlock(&tasklist_lock);
2764 * System call entry points.
2768 * sys_restart_syscall - restart a system call
2770 SYSCALL_DEFINE0(restart_syscall)
2772 struct restart_block *restart = ¤t->restart_block;
2773 return restart->fn(restart);
2776 long do_no_restart_syscall(struct restart_block *param)
2781 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2783 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2784 sigset_t newblocked;
2785 /* A set of now blocked but previously unblocked signals. */
2786 sigandnsets(&newblocked, newset, ¤t->blocked);
2787 retarget_shared_pending(tsk, &newblocked);
2789 tsk->blocked = *newset;
2790 recalc_sigpending();
2794 * set_current_blocked - change current->blocked mask
2797 * It is wrong to change ->blocked directly, this helper should be used
2798 * to ensure the process can't miss a shared signal we are going to block.
2800 void set_current_blocked(sigset_t *newset)
2802 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2803 __set_current_blocked(newset);
2806 void __set_current_blocked(const sigset_t *newset)
2808 struct task_struct *tsk = current;
2811 * In case the signal mask hasn't changed, there is nothing we need
2812 * to do. The current->blocked shouldn't be modified by other task.
2814 if (sigequalsets(&tsk->blocked, newset))
2817 spin_lock_irq(&tsk->sighand->siglock);
2818 __set_task_blocked(tsk, newset);
2819 spin_unlock_irq(&tsk->sighand->siglock);
2823 * This is also useful for kernel threads that want to temporarily
2824 * (or permanently) block certain signals.
2826 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2827 * interface happily blocks "unblockable" signals like SIGKILL
2830 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2832 struct task_struct *tsk = current;
2835 /* Lockless, only current can change ->blocked, never from irq */
2837 *oldset = tsk->blocked;
2841 sigorsets(&newset, &tsk->blocked, set);
2844 sigandnsets(&newset, &tsk->blocked, set);
2853 __set_current_blocked(&newset);
2856 EXPORT_SYMBOL(sigprocmask);
2859 * The api helps set app-provided sigmasks.
2861 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2862 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
2864 int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set,
2865 sigset_t *oldset, size_t sigsetsize)
2870 if (sigsetsize != sizeof(sigset_t))
2872 if (copy_from_user(set, usigmask, sizeof(sigset_t)))
2875 *oldset = current->blocked;
2876 set_current_blocked(set);
2880 EXPORT_SYMBOL(set_user_sigmask);
2882 #ifdef CONFIG_COMPAT
2883 int set_compat_user_sigmask(const compat_sigset_t __user *usigmask,
2884 sigset_t *set, sigset_t *oldset,
2890 if (sigsetsize != sizeof(compat_sigset_t))
2892 if (get_compat_sigset(set, usigmask))
2895 *oldset = current->blocked;
2896 set_current_blocked(set);
2900 EXPORT_SYMBOL(set_compat_user_sigmask);
2904 * restore_user_sigmask:
2905 * usigmask: sigmask passed in from userland.
2906 * sigsaved: saved sigmask when the syscall started and changed the sigmask to
2909 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2910 * epoll_pwait where a new sigmask is passed in from userland for the syscalls.
2912 void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved)
2918 * When signals are pending, do not restore them here.
2919 * Restoring sigmask here can lead to delivering signals that the above
2920 * syscalls are intended to block because of the sigmask passed in.
2922 if (signal_pending(current)) {
2923 current->saved_sigmask = *sigsaved;
2924 set_restore_sigmask();
2929 * This is needed because the fast syscall return path does not restore
2930 * saved_sigmask when signals are not pending.
2932 set_current_blocked(sigsaved);
2934 EXPORT_SYMBOL(restore_user_sigmask);
2937 * sys_rt_sigprocmask - change the list of currently blocked signals
2938 * @how: whether to add, remove, or set signals
2939 * @nset: stores pending signals
2940 * @oset: previous value of signal mask if non-null
2941 * @sigsetsize: size of sigset_t type
2943 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
2944 sigset_t __user *, oset, size_t, sigsetsize)
2946 sigset_t old_set, new_set;
2949 /* XXX: Don't preclude handling different sized sigset_t's. */
2950 if (sigsetsize != sizeof(sigset_t))
2953 old_set = current->blocked;
2956 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
2958 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2960 error = sigprocmask(how, &new_set, NULL);
2966 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
2973 #ifdef CONFIG_COMPAT
2974 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
2975 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
2977 sigset_t old_set = current->blocked;
2979 /* XXX: Don't preclude handling different sized sigset_t's. */
2980 if (sigsetsize != sizeof(sigset_t))
2986 if (get_compat_sigset(&new_set, nset))
2988 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2990 error = sigprocmask(how, &new_set, NULL);
2994 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
2998 static void do_sigpending(sigset_t *set)
3000 spin_lock_irq(¤t->sighand->siglock);
3001 sigorsets(set, ¤t->pending.signal,
3002 ¤t->signal->shared_pending.signal);
3003 spin_unlock_irq(¤t->sighand->siglock);
3005 /* Outside the lock because only this thread touches it. */
3006 sigandsets(set, ¤t->blocked, set);
3010 * sys_rt_sigpending - examine a pending signal that has been raised
3012 * @uset: stores pending signals
3013 * @sigsetsize: size of sigset_t type or larger
3015 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3019 if (sigsetsize > sizeof(*uset))
3022 do_sigpending(&set);
3024 if (copy_to_user(uset, &set, sigsetsize))
3030 #ifdef CONFIG_COMPAT
3031 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3032 compat_size_t, sigsetsize)
3036 if (sigsetsize > sizeof(*uset))
3039 do_sigpending(&set);
3041 return put_compat_sigset(uset, &set, sigsetsize);
3045 static const struct {
3046 unsigned char limit, layout;
3048 [SIGILL] = { NSIGILL, SIL_FAULT },
3049 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3050 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3051 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3052 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3054 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3056 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3057 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3058 [SIGSYS] = { NSIGSYS, SIL_SYS },
3061 static bool known_siginfo_layout(unsigned sig, int si_code)
3063 if (si_code == SI_KERNEL)
3065 else if ((si_code > SI_USER)) {
3066 if (sig_specific_sicodes(sig)) {
3067 if (si_code <= sig_sicodes[sig].limit)
3070 else if (si_code <= NSIGPOLL)
3073 else if (si_code >= SI_DETHREAD)
3075 else if (si_code == SI_ASYNCNL)
3080 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3082 enum siginfo_layout layout = SIL_KILL;
3083 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3084 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3085 (si_code <= sig_sicodes[sig].limit)) {
3086 layout = sig_sicodes[sig].layout;
3087 /* Handle the exceptions */
3088 if ((sig == SIGBUS) &&
3089 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3090 layout = SIL_FAULT_MCEERR;
3091 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3092 layout = SIL_FAULT_BNDERR;
3094 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3095 layout = SIL_FAULT_PKUERR;
3098 else if (si_code <= NSIGPOLL)
3101 if (si_code == SI_TIMER)
3103 else if (si_code == SI_SIGIO)
3105 else if (si_code < 0)
3111 static inline char __user *si_expansion(const siginfo_t __user *info)
3113 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3116 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3118 char __user *expansion = si_expansion(to);
3119 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3121 if (clear_user(expansion, SI_EXPANSION_SIZE))
3126 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3127 const siginfo_t __user *from)
3129 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3130 char __user *expansion = si_expansion(from);
3131 char buf[SI_EXPANSION_SIZE];
3134 * An unknown si_code might need more than
3135 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3136 * extra bytes are 0. This guarantees copy_siginfo_to_user
3137 * will return this data to userspace exactly.
3139 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3141 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3149 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3150 const siginfo_t __user *from)
3152 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3154 to->si_signo = signo;
3155 return post_copy_siginfo_from_user(to, from);
3158 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3160 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3162 return post_copy_siginfo_from_user(to, from);
3165 #ifdef CONFIG_COMPAT
3166 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
3167 const struct kernel_siginfo *from)
3168 #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
3170 return __copy_siginfo_to_user32(to, from, in_x32_syscall());
3172 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3173 const struct kernel_siginfo *from, bool x32_ABI)
3176 struct compat_siginfo new;
3177 memset(&new, 0, sizeof(new));
3179 new.si_signo = from->si_signo;
3180 new.si_errno = from->si_errno;
3181 new.si_code = from->si_code;
3182 switch(siginfo_layout(from->si_signo, from->si_code)) {
3184 new.si_pid = from->si_pid;
3185 new.si_uid = from->si_uid;
3188 new.si_tid = from->si_tid;
3189 new.si_overrun = from->si_overrun;
3190 new.si_int = from->si_int;
3193 new.si_band = from->si_band;
3194 new.si_fd = from->si_fd;
3197 new.si_addr = ptr_to_compat(from->si_addr);
3198 #ifdef __ARCH_SI_TRAPNO
3199 new.si_trapno = from->si_trapno;
3202 case SIL_FAULT_MCEERR:
3203 new.si_addr = ptr_to_compat(from->si_addr);
3204 #ifdef __ARCH_SI_TRAPNO
3205 new.si_trapno = from->si_trapno;
3207 new.si_addr_lsb = from->si_addr_lsb;
3209 case SIL_FAULT_BNDERR:
3210 new.si_addr = ptr_to_compat(from->si_addr);
3211 #ifdef __ARCH_SI_TRAPNO
3212 new.si_trapno = from->si_trapno;
3214 new.si_lower = ptr_to_compat(from->si_lower);
3215 new.si_upper = ptr_to_compat(from->si_upper);
3217 case SIL_FAULT_PKUERR:
3218 new.si_addr = ptr_to_compat(from->si_addr);
3219 #ifdef __ARCH_SI_TRAPNO
3220 new.si_trapno = from->si_trapno;
3222 new.si_pkey = from->si_pkey;
3225 new.si_pid = from->si_pid;
3226 new.si_uid = from->si_uid;
3227 new.si_status = from->si_status;
3228 #ifdef CONFIG_X86_X32_ABI
3230 new._sifields._sigchld_x32._utime = from->si_utime;
3231 new._sifields._sigchld_x32._stime = from->si_stime;
3235 new.si_utime = from->si_utime;
3236 new.si_stime = from->si_stime;
3240 new.si_pid = from->si_pid;
3241 new.si_uid = from->si_uid;
3242 new.si_int = from->si_int;
3245 new.si_call_addr = ptr_to_compat(from->si_call_addr);
3246 new.si_syscall = from->si_syscall;
3247 new.si_arch = from->si_arch;
3251 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3257 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3258 const struct compat_siginfo *from)
3261 to->si_signo = from->si_signo;
3262 to->si_errno = from->si_errno;
3263 to->si_code = from->si_code;
3264 switch(siginfo_layout(from->si_signo, from->si_code)) {
3266 to->si_pid = from->si_pid;
3267 to->si_uid = from->si_uid;
3270 to->si_tid = from->si_tid;
3271 to->si_overrun = from->si_overrun;
3272 to->si_int = from->si_int;
3275 to->si_band = from->si_band;
3276 to->si_fd = from->si_fd;
3279 to->si_addr = compat_ptr(from->si_addr);
3280 #ifdef __ARCH_SI_TRAPNO
3281 to->si_trapno = from->si_trapno;
3284 case SIL_FAULT_MCEERR:
3285 to->si_addr = compat_ptr(from->si_addr);
3286 #ifdef __ARCH_SI_TRAPNO
3287 to->si_trapno = from->si_trapno;
3289 to->si_addr_lsb = from->si_addr_lsb;
3291 case SIL_FAULT_BNDERR:
3292 to->si_addr = compat_ptr(from->si_addr);
3293 #ifdef __ARCH_SI_TRAPNO
3294 to->si_trapno = from->si_trapno;
3296 to->si_lower = compat_ptr(from->si_lower);
3297 to->si_upper = compat_ptr(from->si_upper);
3299 case SIL_FAULT_PKUERR:
3300 to->si_addr = compat_ptr(from->si_addr);
3301 #ifdef __ARCH_SI_TRAPNO
3302 to->si_trapno = from->si_trapno;
3304 to->si_pkey = from->si_pkey;
3307 to->si_pid = from->si_pid;
3308 to->si_uid = from->si_uid;
3309 to->si_status = from->si_status;
3310 #ifdef CONFIG_X86_X32_ABI
3311 if (in_x32_syscall()) {
3312 to->si_utime = from->_sifields._sigchld_x32._utime;
3313 to->si_stime = from->_sifields._sigchld_x32._stime;
3317 to->si_utime = from->si_utime;
3318 to->si_stime = from->si_stime;
3322 to->si_pid = from->si_pid;
3323 to->si_uid = from->si_uid;
3324 to->si_int = from->si_int;
3327 to->si_call_addr = compat_ptr(from->si_call_addr);
3328 to->si_syscall = from->si_syscall;
3329 to->si_arch = from->si_arch;
3335 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3336 const struct compat_siginfo __user *ufrom)
3338 struct compat_siginfo from;
3340 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3343 from.si_signo = signo;
3344 return post_copy_siginfo_from_user32(to, &from);
3347 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3348 const struct compat_siginfo __user *ufrom)
3350 struct compat_siginfo from;
3352 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3355 return post_copy_siginfo_from_user32(to, &from);
3357 #endif /* CONFIG_COMPAT */
3360 * do_sigtimedwait - wait for queued signals specified in @which
3361 * @which: queued signals to wait for
3362 * @info: if non-null, the signal's siginfo is returned here
3363 * @ts: upper bound on process time suspension
3365 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3366 const struct timespec64 *ts)
3368 ktime_t *to = NULL, timeout = KTIME_MAX;
3369 struct task_struct *tsk = current;
3370 sigset_t mask = *which;
3374 if (!timespec64_valid(ts))
3376 timeout = timespec64_to_ktime(*ts);
3381 * Invert the set of allowed signals to get those we want to block.
3383 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3386 spin_lock_irq(&tsk->sighand->siglock);
3387 sig = dequeue_signal(tsk, &mask, info);
3388 if (!sig && timeout) {
3390 * None ready, temporarily unblock those we're interested
3391 * while we are sleeping in so that we'll be awakened when
3392 * they arrive. Unblocking is always fine, we can avoid
3393 * set_current_blocked().
3395 tsk->real_blocked = tsk->blocked;
3396 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3397 recalc_sigpending();
3398 spin_unlock_irq(&tsk->sighand->siglock);
3400 __set_current_state(TASK_INTERRUPTIBLE);
3401 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3403 spin_lock_irq(&tsk->sighand->siglock);
3404 __set_task_blocked(tsk, &tsk->real_blocked);
3405 sigemptyset(&tsk->real_blocked);
3406 sig = dequeue_signal(tsk, &mask, info);
3408 spin_unlock_irq(&tsk->sighand->siglock);
3412 return ret ? -EINTR : -EAGAIN;
3416 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3418 * @uthese: queued signals to wait for
3419 * @uinfo: if non-null, the signal's siginfo is returned here
3420 * @uts: upper bound on process time suspension
3421 * @sigsetsize: size of sigset_t type
3423 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3424 siginfo_t __user *, uinfo,
3425 const struct __kernel_timespec __user *, uts,
3429 struct timespec64 ts;
3430 kernel_siginfo_t info;
3433 /* XXX: Don't preclude handling different sized sigset_t's. */
3434 if (sigsetsize != sizeof(sigset_t))
3437 if (copy_from_user(&these, uthese, sizeof(these)))
3441 if (get_timespec64(&ts, uts))
3445 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3447 if (ret > 0 && uinfo) {
3448 if (copy_siginfo_to_user(uinfo, &info))
3455 #ifdef CONFIG_COMPAT_32BIT_TIME
3456 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3457 siginfo_t __user *, uinfo,
3458 const struct old_timespec32 __user *, uts,
3462 struct timespec64 ts;
3463 kernel_siginfo_t info;
3466 if (sigsetsize != sizeof(sigset_t))
3469 if (copy_from_user(&these, uthese, sizeof(these)))
3473 if (get_old_timespec32(&ts, uts))
3477 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3479 if (ret > 0 && uinfo) {
3480 if (copy_siginfo_to_user(uinfo, &info))
3488 #ifdef CONFIG_COMPAT
3489 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3490 struct compat_siginfo __user *, uinfo,
3491 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3494 struct timespec64 t;
3495 kernel_siginfo_t info;
3498 if (sigsetsize != sizeof(sigset_t))
3501 if (get_compat_sigset(&s, uthese))
3505 if (get_timespec64(&t, uts))
3509 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3511 if (ret > 0 && uinfo) {
3512 if (copy_siginfo_to_user32(uinfo, &info))
3519 #ifdef CONFIG_COMPAT_32BIT_TIME
3520 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3521 struct compat_siginfo __user *, uinfo,
3522 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3525 struct timespec64 t;
3526 kernel_siginfo_t info;
3529 if (sigsetsize != sizeof(sigset_t))
3532 if (get_compat_sigset(&s, uthese))
3536 if (get_old_timespec32(&t, uts))
3540 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3542 if (ret > 0 && uinfo) {
3543 if (copy_siginfo_to_user32(uinfo, &info))
3552 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3554 clear_siginfo(info);
3555 info->si_signo = sig;
3557 info->si_code = SI_USER;
3558 info->si_pid = task_tgid_vnr(current);
3559 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3563 * sys_kill - send a signal to a process
3564 * @pid: the PID of the process
3565 * @sig: signal to be sent
3567 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3569 struct kernel_siginfo info;
3571 prepare_kill_siginfo(sig, &info);
3573 return kill_something_info(sig, &info, pid);
3577 * Verify that the signaler and signalee either are in the same pid namespace
3578 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3581 static bool access_pidfd_pidns(struct pid *pid)
3583 struct pid_namespace *active = task_active_pid_ns(current);
3584 struct pid_namespace *p = ns_of_pid(pid);
3597 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, siginfo_t *info)
3599 #ifdef CONFIG_COMPAT
3601 * Avoid hooking up compat syscalls and instead handle necessary
3602 * conversions here. Note, this is a stop-gap measure and should not be
3603 * considered a generic solution.
3605 if (in_compat_syscall())
3606 return copy_siginfo_from_user32(
3607 kinfo, (struct compat_siginfo __user *)info);
3609 return copy_siginfo_from_user(kinfo, info);
3612 static struct pid *pidfd_to_pid(const struct file *file)
3614 if (file->f_op == &pidfd_fops)
3615 return file->private_data;
3617 return tgid_pidfd_to_pid(file);
3621 * sys_pidfd_send_signal - send a signal to a process through a task file
3623 * @pidfd: the file descriptor of the process
3624 * @sig: signal to be sent
3625 * @info: the signal info
3626 * @flags: future flags to be passed
3628 * The syscall currently only signals via PIDTYPE_PID which covers
3629 * kill(<positive-pid>, <signal>. It does not signal threads or process
3631 * In order to extend the syscall to threads and process groups the @flags
3632 * argument should be used. In essence, the @flags argument will determine
3633 * what is signaled and not the file descriptor itself. Put in other words,
3634 * grouping is a property of the flags argument not a property of the file
3637 * Return: 0 on success, negative errno on failure
3639 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3640 siginfo_t __user *, info, unsigned int, flags)
3645 kernel_siginfo_t kinfo;
3647 /* Enforce flags be set to 0 until we add an extension. */
3655 /* Is this a pidfd? */
3656 pid = pidfd_to_pid(f.file);
3663 if (!access_pidfd_pidns(pid))
3667 ret = copy_siginfo_from_user_any(&kinfo, info);
3672 if (unlikely(sig != kinfo.si_signo))
3675 /* Only allow sending arbitrary signals to yourself. */
3677 if ((task_pid(current) != pid) &&
3678 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3681 prepare_kill_siginfo(sig, &kinfo);
3684 ret = kill_pid_info(sig, &kinfo, pid);
3692 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3694 struct task_struct *p;
3698 p = find_task_by_vpid(pid);
3699 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3700 error = check_kill_permission(sig, info, p);
3702 * The null signal is a permissions and process existence
3703 * probe. No signal is actually delivered.
3705 if (!error && sig) {
3706 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3708 * If lock_task_sighand() failed we pretend the task
3709 * dies after receiving the signal. The window is tiny,
3710 * and the signal is private anyway.
3712 if (unlikely(error == -ESRCH))
3721 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3723 struct kernel_siginfo info;
3725 clear_siginfo(&info);
3726 info.si_signo = sig;
3728 info.si_code = SI_TKILL;
3729 info.si_pid = task_tgid_vnr(current);
3730 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3732 return do_send_specific(tgid, pid, sig, &info);
3736 * sys_tgkill - send signal to one specific thread
3737 * @tgid: the thread group ID of the thread
3738 * @pid: the PID of the thread
3739 * @sig: signal to be sent
3741 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3742 * exists but it's not belonging to the target process anymore. This
3743 * method solves the problem of threads exiting and PIDs getting reused.
3745 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3747 /* This is only valid for single tasks */
3748 if (pid <= 0 || tgid <= 0)
3751 return do_tkill(tgid, pid, sig);
3755 * sys_tkill - send signal to one specific task
3756 * @pid: the PID of the task
3757 * @sig: signal to be sent
3759 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3761 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3763 /* This is only valid for single tasks */
3767 return do_tkill(0, pid, sig);
3770 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3772 /* Not even root can pretend to send signals from the kernel.
3773 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3775 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3776 (task_pid_vnr(current) != pid))
3779 /* POSIX.1b doesn't mention process groups. */
3780 return kill_proc_info(sig, info, pid);
3784 * sys_rt_sigqueueinfo - send signal information to a signal
3785 * @pid: the PID of the thread
3786 * @sig: signal to be sent
3787 * @uinfo: signal info to be sent
3789 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3790 siginfo_t __user *, uinfo)
3792 kernel_siginfo_t info;
3793 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3796 return do_rt_sigqueueinfo(pid, sig, &info);
3799 #ifdef CONFIG_COMPAT
3800 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3803 struct compat_siginfo __user *, uinfo)
3805 kernel_siginfo_t info;
3806 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3809 return do_rt_sigqueueinfo(pid, sig, &info);
3813 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
3815 /* This is only valid for single tasks */
3816 if (pid <= 0 || tgid <= 0)
3819 /* Not even root can pretend to send signals from the kernel.
3820 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3822 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3823 (task_pid_vnr(current) != pid))
3826 return do_send_specific(tgid, pid, sig, info);
3829 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3830 siginfo_t __user *, uinfo)
3832 kernel_siginfo_t info;
3833 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3836 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3839 #ifdef CONFIG_COMPAT
3840 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3844 struct compat_siginfo __user *, uinfo)
3846 kernel_siginfo_t info;
3847 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3850 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3855 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3857 void kernel_sigaction(int sig, __sighandler_t action)
3859 spin_lock_irq(¤t->sighand->siglock);
3860 current->sighand->action[sig - 1].sa.sa_handler = action;
3861 if (action == SIG_IGN) {
3865 sigaddset(&mask, sig);
3867 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3868 flush_sigqueue_mask(&mask, ¤t->pending);
3869 recalc_sigpending();
3871 spin_unlock_irq(¤t->sighand->siglock);
3873 EXPORT_SYMBOL(kernel_sigaction);
3875 void __weak sigaction_compat_abi(struct k_sigaction *act,
3876 struct k_sigaction *oact)
3880 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3882 struct task_struct *p = current, *t;
3883 struct k_sigaction *k;
3886 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3889 k = &p->sighand->action[sig-1];
3891 spin_lock_irq(&p->sighand->siglock);
3895 sigaction_compat_abi(act, oact);
3898 sigdelsetmask(&act->sa.sa_mask,
3899 sigmask(SIGKILL) | sigmask(SIGSTOP));
3903 * "Setting a signal action to SIG_IGN for a signal that is
3904 * pending shall cause the pending signal to be discarded,
3905 * whether or not it is blocked."
3907 * "Setting a signal action to SIG_DFL for a signal that is
3908 * pending and whose default action is to ignore the signal
3909 * (for example, SIGCHLD), shall cause the pending signal to
3910 * be discarded, whether or not it is blocked"
3912 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3914 sigaddset(&mask, sig);
3915 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3916 for_each_thread(p, t)
3917 flush_sigqueue_mask(&mask, &t->pending);
3921 spin_unlock_irq(&p->sighand->siglock);
3926 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
3929 struct task_struct *t = current;
3932 memset(oss, 0, sizeof(stack_t));
3933 oss->ss_sp = (void __user *) t->sas_ss_sp;
3934 oss->ss_size = t->sas_ss_size;
3935 oss->ss_flags = sas_ss_flags(sp) |
3936 (current->sas_ss_flags & SS_FLAG_BITS);
3940 void __user *ss_sp = ss->ss_sp;
3941 size_t ss_size = ss->ss_size;
3942 unsigned ss_flags = ss->ss_flags;
3945 if (unlikely(on_sig_stack(sp)))
3948 ss_mode = ss_flags & ~SS_FLAG_BITS;
3949 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
3953 if (ss_mode == SS_DISABLE) {
3957 if (unlikely(ss_size < min_ss_size))
3961 t->sas_ss_sp = (unsigned long) ss_sp;
3962 t->sas_ss_size = ss_size;
3963 t->sas_ss_flags = ss_flags;
3968 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
3972 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
3974 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
3975 current_user_stack_pointer(),
3977 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
3982 int restore_altstack(const stack_t __user *uss)
3985 if (copy_from_user(&new, uss, sizeof(stack_t)))
3987 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
3989 /* squash all but EFAULT for now */
3993 int __save_altstack(stack_t __user *uss, unsigned long sp)
3995 struct task_struct *t = current;
3996 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
3997 __put_user(t->sas_ss_flags, &uss->ss_flags) |
3998 __put_user(t->sas_ss_size, &uss->ss_size);
4001 if (t->sas_ss_flags & SS_AUTODISARM)
4006 #ifdef CONFIG_COMPAT
4007 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4008 compat_stack_t __user *uoss_ptr)
4014 compat_stack_t uss32;
4015 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4017 uss.ss_sp = compat_ptr(uss32.ss_sp);
4018 uss.ss_flags = uss32.ss_flags;
4019 uss.ss_size = uss32.ss_size;
4021 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4022 compat_user_stack_pointer(),
4023 COMPAT_MINSIGSTKSZ);
4024 if (ret >= 0 && uoss_ptr) {
4026 memset(&old, 0, sizeof(old));
4027 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4028 old.ss_flags = uoss.ss_flags;
4029 old.ss_size = uoss.ss_size;
4030 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4036 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4037 const compat_stack_t __user *, uss_ptr,
4038 compat_stack_t __user *, uoss_ptr)
4040 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4043 int compat_restore_altstack(const compat_stack_t __user *uss)
4045 int err = do_compat_sigaltstack(uss, NULL);
4046 /* squash all but -EFAULT for now */
4047 return err == -EFAULT ? err : 0;
4050 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4053 struct task_struct *t = current;
4054 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4056 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4057 __put_user(t->sas_ss_size, &uss->ss_size);
4060 if (t->sas_ss_flags & SS_AUTODISARM)
4066 #ifdef __ARCH_WANT_SYS_SIGPENDING
4069 * sys_sigpending - examine pending signals
4070 * @uset: where mask of pending signal is returned
4072 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4076 if (sizeof(old_sigset_t) > sizeof(*uset))
4079 do_sigpending(&set);
4081 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4087 #ifdef CONFIG_COMPAT
4088 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4092 do_sigpending(&set);
4094 return put_user(set.sig[0], set32);
4100 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4102 * sys_sigprocmask - examine and change blocked signals
4103 * @how: whether to add, remove, or set signals
4104 * @nset: signals to add or remove (if non-null)
4105 * @oset: previous value of signal mask if non-null
4107 * Some platforms have their own version with special arguments;
4108 * others support only sys_rt_sigprocmask.
4111 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4112 old_sigset_t __user *, oset)
4114 old_sigset_t old_set, new_set;
4115 sigset_t new_blocked;
4117 old_set = current->blocked.sig[0];
4120 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4123 new_blocked = current->blocked;
4127 sigaddsetmask(&new_blocked, new_set);
4130 sigdelsetmask(&new_blocked, new_set);
4133 new_blocked.sig[0] = new_set;
4139 set_current_blocked(&new_blocked);
4143 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4149 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4151 #ifndef CONFIG_ODD_RT_SIGACTION
4153 * sys_rt_sigaction - alter an action taken by a process
4154 * @sig: signal to be sent
4155 * @act: new sigaction
4156 * @oact: used to save the previous sigaction
4157 * @sigsetsize: size of sigset_t type
4159 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4160 const struct sigaction __user *, act,
4161 struct sigaction __user *, oact,
4164 struct k_sigaction new_sa, old_sa;
4167 /* XXX: Don't preclude handling different sized sigset_t's. */
4168 if (sigsetsize != sizeof(sigset_t))
4171 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4174 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4178 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4183 #ifdef CONFIG_COMPAT
4184 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4185 const struct compat_sigaction __user *, act,
4186 struct compat_sigaction __user *, oact,
4187 compat_size_t, sigsetsize)
4189 struct k_sigaction new_ka, old_ka;
4190 #ifdef __ARCH_HAS_SA_RESTORER
4191 compat_uptr_t restorer;
4195 /* XXX: Don't preclude handling different sized sigset_t's. */
4196 if (sigsetsize != sizeof(compat_sigset_t))
4200 compat_uptr_t handler;
4201 ret = get_user(handler, &act->sa_handler);
4202 new_ka.sa.sa_handler = compat_ptr(handler);
4203 #ifdef __ARCH_HAS_SA_RESTORER
4204 ret |= get_user(restorer, &act->sa_restorer);
4205 new_ka.sa.sa_restorer = compat_ptr(restorer);
4207 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4208 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4213 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4215 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4217 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4218 sizeof(oact->sa_mask));
4219 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4220 #ifdef __ARCH_HAS_SA_RESTORER
4221 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4222 &oact->sa_restorer);
4228 #endif /* !CONFIG_ODD_RT_SIGACTION */
4230 #ifdef CONFIG_OLD_SIGACTION
4231 SYSCALL_DEFINE3(sigaction, int, sig,
4232 const struct old_sigaction __user *, act,
4233 struct old_sigaction __user *, oact)
4235 struct k_sigaction new_ka, old_ka;
4240 if (!access_ok(act, sizeof(*act)) ||
4241 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4242 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4243 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4244 __get_user(mask, &act->sa_mask))
4246 #ifdef __ARCH_HAS_KA_RESTORER
4247 new_ka.ka_restorer = NULL;
4249 siginitset(&new_ka.sa.sa_mask, mask);
4252 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4255 if (!access_ok(oact, sizeof(*oact)) ||
4256 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4257 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4258 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4259 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4266 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4267 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4268 const struct compat_old_sigaction __user *, act,
4269 struct compat_old_sigaction __user *, oact)
4271 struct k_sigaction new_ka, old_ka;
4273 compat_old_sigset_t mask;
4274 compat_uptr_t handler, restorer;
4277 if (!access_ok(act, sizeof(*act)) ||
4278 __get_user(handler, &act->sa_handler) ||
4279 __get_user(restorer, &act->sa_restorer) ||
4280 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4281 __get_user(mask, &act->sa_mask))
4284 #ifdef __ARCH_HAS_KA_RESTORER
4285 new_ka.ka_restorer = NULL;
4287 new_ka.sa.sa_handler = compat_ptr(handler);
4288 new_ka.sa.sa_restorer = compat_ptr(restorer);
4289 siginitset(&new_ka.sa.sa_mask, mask);
4292 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4295 if (!access_ok(oact, sizeof(*oact)) ||
4296 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4297 &oact->sa_handler) ||
4298 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4299 &oact->sa_restorer) ||
4300 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4301 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4308 #ifdef CONFIG_SGETMASK_SYSCALL
4311 * For backwards compatibility. Functionality superseded by sigprocmask.
4313 SYSCALL_DEFINE0(sgetmask)
4316 return current->blocked.sig[0];
4319 SYSCALL_DEFINE1(ssetmask, int, newmask)
4321 int old = current->blocked.sig[0];
4324 siginitset(&newset, newmask);
4325 set_current_blocked(&newset);
4329 #endif /* CONFIG_SGETMASK_SYSCALL */
4331 #ifdef __ARCH_WANT_SYS_SIGNAL
4333 * For backwards compatibility. Functionality superseded by sigaction.
4335 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4337 struct k_sigaction new_sa, old_sa;
4340 new_sa.sa.sa_handler = handler;
4341 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4342 sigemptyset(&new_sa.sa.sa_mask);
4344 ret = do_sigaction(sig, &new_sa, &old_sa);
4346 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4348 #endif /* __ARCH_WANT_SYS_SIGNAL */
4350 #ifdef __ARCH_WANT_SYS_PAUSE
4352 SYSCALL_DEFINE0(pause)
4354 while (!signal_pending(current)) {
4355 __set_current_state(TASK_INTERRUPTIBLE);
4358 return -ERESTARTNOHAND;
4363 static int sigsuspend(sigset_t *set)
4365 current->saved_sigmask = current->blocked;
4366 set_current_blocked(set);
4368 while (!signal_pending(current)) {
4369 __set_current_state(TASK_INTERRUPTIBLE);
4372 set_restore_sigmask();
4373 return -ERESTARTNOHAND;
4377 * sys_rt_sigsuspend - replace the signal mask for a value with the
4378 * @unewset value until a signal is received
4379 * @unewset: new signal mask value
4380 * @sigsetsize: size of sigset_t type
4382 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4386 /* XXX: Don't preclude handling different sized sigset_t's. */
4387 if (sigsetsize != sizeof(sigset_t))
4390 if (copy_from_user(&newset, unewset, sizeof(newset)))
4392 return sigsuspend(&newset);
4395 #ifdef CONFIG_COMPAT
4396 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4400 /* XXX: Don't preclude handling different sized sigset_t's. */
4401 if (sigsetsize != sizeof(sigset_t))
4404 if (get_compat_sigset(&newset, unewset))
4406 return sigsuspend(&newset);
4410 #ifdef CONFIG_OLD_SIGSUSPEND
4411 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4414 siginitset(&blocked, mask);
4415 return sigsuspend(&blocked);
4418 #ifdef CONFIG_OLD_SIGSUSPEND3
4419 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4422 siginitset(&blocked, mask);
4423 return sigsuspend(&blocked);
4427 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4432 static inline void siginfo_buildtime_checks(void)
4434 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4436 /* Verify the offsets in the two siginfos match */
4437 #define CHECK_OFFSET(field) \
4438 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4441 CHECK_OFFSET(si_pid);
4442 CHECK_OFFSET(si_uid);
4445 CHECK_OFFSET(si_tid);
4446 CHECK_OFFSET(si_overrun);
4447 CHECK_OFFSET(si_value);
4450 CHECK_OFFSET(si_pid);
4451 CHECK_OFFSET(si_uid);
4452 CHECK_OFFSET(si_value);
4455 CHECK_OFFSET(si_pid);
4456 CHECK_OFFSET(si_uid);
4457 CHECK_OFFSET(si_status);
4458 CHECK_OFFSET(si_utime);
4459 CHECK_OFFSET(si_stime);
4462 CHECK_OFFSET(si_addr);
4463 CHECK_OFFSET(si_addr_lsb);
4464 CHECK_OFFSET(si_lower);
4465 CHECK_OFFSET(si_upper);
4466 CHECK_OFFSET(si_pkey);
4469 CHECK_OFFSET(si_band);
4470 CHECK_OFFSET(si_fd);
4473 CHECK_OFFSET(si_call_addr);
4474 CHECK_OFFSET(si_syscall);
4475 CHECK_OFFSET(si_arch);
4479 void __init signals_init(void)
4481 siginfo_buildtime_checks();
4483 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
4486 #ifdef CONFIG_KGDB_KDB
4487 #include <linux/kdb.h>
4489 * kdb_send_sig - Allows kdb to send signals without exposing
4490 * signal internals. This function checks if the required locks are
4491 * available before calling the main signal code, to avoid kdb
4494 void kdb_send_sig(struct task_struct *t, int sig)
4496 static struct task_struct *kdb_prev_t;
4498 if (!spin_trylock(&t->sighand->siglock)) {
4499 kdb_printf("Can't do kill command now.\n"
4500 "The sigmask lock is held somewhere else in "
4501 "kernel, try again later\n");
4504 new_t = kdb_prev_t != t;
4506 if (t->state != TASK_RUNNING && new_t) {
4507 spin_unlock(&t->sighand->siglock);
4508 kdb_printf("Process is not RUNNING, sending a signal from "
4509 "kdb risks deadlock\n"
4510 "on the run queue locks. "
4511 "The signal has _not_ been sent.\n"
4512 "Reissue the kill command if you want to risk "
4516 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4517 spin_unlock(&t->sighand->siglock);
4519 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4522 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4524 #endif /* CONFIG_KGDB_KDB */