1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
9 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
10 * Changes to use preallocated sigqueue structures
11 * to allow signals to be sent reliably.
14 #include <linux/slab.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/debug.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/sched/cputime.h>
23 #include <linux/file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/tty.h>
27 #include <linux/binfmts.h>
28 #include <linux/coredump.h>
29 #include <linux/security.h>
30 #include <linux/syscalls.h>
31 #include <linux/ptrace.h>
32 #include <linux/signal.h>
33 #include <linux/signalfd.h>
34 #include <linux/ratelimit.h>
35 #include <linux/tracehook.h>
36 #include <linux/capability.h>
37 #include <linux/freezer.h>
38 #include <linux/pid_namespace.h>
39 #include <linux/nsproxy.h>
40 #include <linux/user_namespace.h>
41 #include <linux/uprobes.h>
42 #include <linux/compat.h>
43 #include <linux/cn_proc.h>
44 #include <linux/compiler.h>
45 #include <linux/posix-timers.h>
46 #include <linux/livepatch.h>
47 #include <linux/cgroup.h>
48 #include <linux/audit.h>
50 #define CREATE_TRACE_POINTS
51 #include <trace/events/signal.h>
53 #include <asm/param.h>
54 #include <linux/uaccess.h>
55 #include <asm/unistd.h>
56 #include <asm/siginfo.h>
57 #include <asm/cacheflush.h>
60 * SLAB caches for signal bits.
63 static struct kmem_cache *sigqueue_cachep;
65 int print_fatal_signals __read_mostly;
67 static void __user *sig_handler(struct task_struct *t, int sig)
69 return t->sighand->action[sig - 1].sa.sa_handler;
72 static inline bool sig_handler_ignored(void __user *handler, int sig)
74 /* Is it explicitly or implicitly ignored? */
75 return handler == SIG_IGN ||
76 (handler == SIG_DFL && sig_kernel_ignore(sig));
79 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
83 handler = sig_handler(t, sig);
85 /* SIGKILL and SIGSTOP may not be sent to the global init */
86 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
89 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
90 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
93 /* Only allow kernel generated signals to this kthread */
94 if (unlikely((t->flags & PF_KTHREAD) &&
95 (handler == SIG_KTHREAD_KERNEL) && !force))
98 return sig_handler_ignored(handler, sig);
101 static bool sig_ignored(struct task_struct *t, int sig, bool force)
104 * Blocked signals are never ignored, since the
105 * signal handler may change by the time it is
108 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
112 * Tracers may want to know about even ignored signal unless it
113 * is SIGKILL which can't be reported anyway but can be ignored
114 * by SIGNAL_UNKILLABLE task.
116 if (t->ptrace && sig != SIGKILL)
119 return sig_task_ignored(t, sig, force);
123 * Re-calculate pending state from the set of locally pending
124 * signals, globally pending signals, and blocked signals.
126 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
131 switch (_NSIG_WORDS) {
133 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
134 ready |= signal->sig[i] &~ blocked->sig[i];
137 case 4: ready = signal->sig[3] &~ blocked->sig[3];
138 ready |= signal->sig[2] &~ blocked->sig[2];
139 ready |= signal->sig[1] &~ blocked->sig[1];
140 ready |= signal->sig[0] &~ blocked->sig[0];
143 case 2: ready = signal->sig[1] &~ blocked->sig[1];
144 ready |= signal->sig[0] &~ blocked->sig[0];
147 case 1: ready = signal->sig[0] &~ blocked->sig[0];
152 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
154 static bool recalc_sigpending_tsk(struct task_struct *t)
156 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
157 PENDING(&t->pending, &t->blocked) ||
158 PENDING(&t->signal->shared_pending, &t->blocked) ||
159 cgroup_task_frozen(t)) {
160 set_tsk_thread_flag(t, TIF_SIGPENDING);
165 * We must never clear the flag in another thread, or in current
166 * when it's possible the current syscall is returning -ERESTART*.
167 * So we don't clear it here, and only callers who know they should do.
173 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
174 * This is superfluous when called on current, the wakeup is a harmless no-op.
176 void recalc_sigpending_and_wake(struct task_struct *t)
178 if (recalc_sigpending_tsk(t))
179 signal_wake_up(t, 0);
182 void recalc_sigpending(void)
184 if (!recalc_sigpending_tsk(current) && !freezing(current) &&
185 !klp_patch_pending(current))
186 clear_thread_flag(TIF_SIGPENDING);
189 EXPORT_SYMBOL(recalc_sigpending);
191 void calculate_sigpending(void)
193 /* Have any signals or users of TIF_SIGPENDING been delayed
196 spin_lock_irq(¤t->sighand->siglock);
197 set_tsk_thread_flag(current, TIF_SIGPENDING);
199 spin_unlock_irq(¤t->sighand->siglock);
202 /* Given the mask, find the first available signal that should be serviced. */
204 #define SYNCHRONOUS_MASK \
205 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
206 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
208 int next_signal(struct sigpending *pending, sigset_t *mask)
210 unsigned long i, *s, *m, x;
213 s = pending->signal.sig;
217 * Handle the first word specially: it contains the
218 * synchronous signals that need to be dequeued first.
222 if (x & SYNCHRONOUS_MASK)
223 x &= SYNCHRONOUS_MASK;
228 switch (_NSIG_WORDS) {
230 for (i = 1; i < _NSIG_WORDS; ++i) {
234 sig = ffz(~x) + i*_NSIG_BPW + 1;
243 sig = ffz(~x) + _NSIG_BPW + 1;
254 static inline void print_dropped_signal(int sig)
256 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
258 if (!print_fatal_signals)
261 if (!__ratelimit(&ratelimit_state))
264 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
265 current->comm, current->pid, sig);
269 * task_set_jobctl_pending - set jobctl pending bits
271 * @mask: pending bits to set
273 * Clear @mask from @task->jobctl. @mask must be subset of
274 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
275 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
276 * cleared. If @task is already being killed or exiting, this function
280 * Must be called with @task->sighand->siglock held.
283 * %true if @mask is set, %false if made noop because @task was dying.
285 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
287 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
288 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
289 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
291 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
294 if (mask & JOBCTL_STOP_SIGMASK)
295 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
297 task->jobctl |= mask;
302 * task_clear_jobctl_trapping - clear jobctl trapping bit
305 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
306 * Clear it and wake up the ptracer. Note that we don't need any further
307 * locking. @task->siglock guarantees that @task->parent points to the
311 * Must be called with @task->sighand->siglock held.
313 void task_clear_jobctl_trapping(struct task_struct *task)
315 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
316 task->jobctl &= ~JOBCTL_TRAPPING;
317 smp_mb(); /* advised by wake_up_bit() */
318 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
323 * task_clear_jobctl_pending - clear jobctl pending bits
325 * @mask: pending bits to clear
327 * Clear @mask from @task->jobctl. @mask must be subset of
328 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
329 * STOP bits are cleared together.
331 * If clearing of @mask leaves no stop or trap pending, this function calls
332 * task_clear_jobctl_trapping().
335 * Must be called with @task->sighand->siglock held.
337 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
339 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
341 if (mask & JOBCTL_STOP_PENDING)
342 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
344 task->jobctl &= ~mask;
346 if (!(task->jobctl & JOBCTL_PENDING_MASK))
347 task_clear_jobctl_trapping(task);
351 * task_participate_group_stop - participate in a group stop
352 * @task: task participating in a group stop
354 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
355 * Group stop states are cleared and the group stop count is consumed if
356 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
357 * stop, the appropriate `SIGNAL_*` flags are set.
360 * Must be called with @task->sighand->siglock held.
363 * %true if group stop completion should be notified to the parent, %false
366 static bool task_participate_group_stop(struct task_struct *task)
368 struct signal_struct *sig = task->signal;
369 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
371 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
373 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
378 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
379 sig->group_stop_count--;
382 * Tell the caller to notify completion iff we are entering into a
383 * fresh group stop. Read comment in do_signal_stop() for details.
385 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
386 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
392 void task_join_group_stop(struct task_struct *task)
394 unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
395 struct signal_struct *sig = current->signal;
397 if (sig->group_stop_count) {
398 sig->group_stop_count++;
399 mask |= JOBCTL_STOP_CONSUME;
400 } else if (!(sig->flags & SIGNAL_STOP_STOPPED))
403 /* Have the new thread join an on-going signal group stop */
404 task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
408 * allocate a new signal queue record
409 * - this may be called without locks if and only if t == current, otherwise an
410 * appropriate lock must be held to stop the target task from exiting
412 static struct sigqueue *
413 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
415 struct sigqueue *q = NULL;
416 struct user_struct *user;
420 * Protect access to @t credentials. This can go away when all
421 * callers hold rcu read lock.
423 * NOTE! A pending signal will hold on to the user refcount,
424 * and we get/put the refcount only when the sigpending count
425 * changes from/to zero.
428 user = __task_cred(t)->user;
429 sigpending = atomic_inc_return(&user->sigpending);
434 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
435 q = kmem_cache_alloc(sigqueue_cachep, flags);
437 print_dropped_signal(sig);
440 if (unlikely(q == NULL)) {
441 if (atomic_dec_and_test(&user->sigpending))
444 INIT_LIST_HEAD(&q->list);
452 static void __sigqueue_free(struct sigqueue *q)
454 if (q->flags & SIGQUEUE_PREALLOC)
456 if (atomic_dec_and_test(&q->user->sigpending))
458 kmem_cache_free(sigqueue_cachep, q);
461 void flush_sigqueue(struct sigpending *queue)
465 sigemptyset(&queue->signal);
466 while (!list_empty(&queue->list)) {
467 q = list_entry(queue->list.next, struct sigqueue , list);
468 list_del_init(&q->list);
474 * Flush all pending signals for this kthread.
476 void flush_signals(struct task_struct *t)
480 spin_lock_irqsave(&t->sighand->siglock, flags);
481 clear_tsk_thread_flag(t, TIF_SIGPENDING);
482 flush_sigqueue(&t->pending);
483 flush_sigqueue(&t->signal->shared_pending);
484 spin_unlock_irqrestore(&t->sighand->siglock, flags);
486 EXPORT_SYMBOL(flush_signals);
488 #ifdef CONFIG_POSIX_TIMERS
489 static void __flush_itimer_signals(struct sigpending *pending)
491 sigset_t signal, retain;
492 struct sigqueue *q, *n;
494 signal = pending->signal;
495 sigemptyset(&retain);
497 list_for_each_entry_safe(q, n, &pending->list, list) {
498 int sig = q->info.si_signo;
500 if (likely(q->info.si_code != SI_TIMER)) {
501 sigaddset(&retain, sig);
503 sigdelset(&signal, sig);
504 list_del_init(&q->list);
509 sigorsets(&pending->signal, &signal, &retain);
512 void flush_itimer_signals(void)
514 struct task_struct *tsk = current;
517 spin_lock_irqsave(&tsk->sighand->siglock, flags);
518 __flush_itimer_signals(&tsk->pending);
519 __flush_itimer_signals(&tsk->signal->shared_pending);
520 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
524 void ignore_signals(struct task_struct *t)
528 for (i = 0; i < _NSIG; ++i)
529 t->sighand->action[i].sa.sa_handler = SIG_IGN;
535 * Flush all handlers for a task.
539 flush_signal_handlers(struct task_struct *t, int force_default)
542 struct k_sigaction *ka = &t->sighand->action[0];
543 for (i = _NSIG ; i != 0 ; i--) {
544 if (force_default || ka->sa.sa_handler != SIG_IGN)
545 ka->sa.sa_handler = SIG_DFL;
547 #ifdef __ARCH_HAS_SA_RESTORER
548 ka->sa.sa_restorer = NULL;
550 sigemptyset(&ka->sa.sa_mask);
555 bool unhandled_signal(struct task_struct *tsk, int sig)
557 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
558 if (is_global_init(tsk))
561 if (handler != SIG_IGN && handler != SIG_DFL)
564 /* if ptraced, let the tracer determine */
568 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
571 struct sigqueue *q, *first = NULL;
574 * Collect the siginfo appropriate to this signal. Check if
575 * there is another siginfo for the same signal.
577 list_for_each_entry(q, &list->list, list) {
578 if (q->info.si_signo == sig) {
585 sigdelset(&list->signal, sig);
589 list_del_init(&first->list);
590 copy_siginfo(info, &first->info);
593 (first->flags & SIGQUEUE_PREALLOC) &&
594 (info->si_code == SI_TIMER) &&
595 (info->si_sys_private);
597 __sigqueue_free(first);
600 * Ok, it wasn't in the queue. This must be
601 * a fast-pathed signal or we must have been
602 * out of queue space. So zero out the info.
605 info->si_signo = sig;
607 info->si_code = SI_USER;
613 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
614 kernel_siginfo_t *info, bool *resched_timer)
616 int sig = next_signal(pending, mask);
619 collect_signal(sig, pending, info, resched_timer);
624 * Dequeue a signal and return the element to the caller, which is
625 * expected to free it.
627 * All callers have to hold the siglock.
629 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
631 bool resched_timer = false;
634 /* We only dequeue private signals from ourselves, we don't let
635 * signalfd steal them
637 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
639 signr = __dequeue_signal(&tsk->signal->shared_pending,
640 mask, info, &resched_timer);
641 #ifdef CONFIG_POSIX_TIMERS
645 * itimers are process shared and we restart periodic
646 * itimers in the signal delivery path to prevent DoS
647 * attacks in the high resolution timer case. This is
648 * compliant with the old way of self-restarting
649 * itimers, as the SIGALRM is a legacy signal and only
650 * queued once. Changing the restart behaviour to
651 * restart the timer in the signal dequeue path is
652 * reducing the timer noise on heavy loaded !highres
655 if (unlikely(signr == SIGALRM)) {
656 struct hrtimer *tmr = &tsk->signal->real_timer;
658 if (!hrtimer_is_queued(tmr) &&
659 tsk->signal->it_real_incr != 0) {
660 hrtimer_forward(tmr, tmr->base->get_time(),
661 tsk->signal->it_real_incr);
662 hrtimer_restart(tmr);
672 if (unlikely(sig_kernel_stop(signr))) {
674 * Set a marker that we have dequeued a stop signal. Our
675 * caller might release the siglock and then the pending
676 * stop signal it is about to process is no longer in the
677 * pending bitmasks, but must still be cleared by a SIGCONT
678 * (and overruled by a SIGKILL). So those cases clear this
679 * shared flag after we've set it. Note that this flag may
680 * remain set after the signal we return is ignored or
681 * handled. That doesn't matter because its only purpose
682 * is to alert stop-signal processing code when another
683 * processor has come along and cleared the flag.
685 current->jobctl |= JOBCTL_STOP_DEQUEUED;
687 #ifdef CONFIG_POSIX_TIMERS
690 * Release the siglock to ensure proper locking order
691 * of timer locks outside of siglocks. Note, we leave
692 * irqs disabled here, since the posix-timers code is
693 * about to disable them again anyway.
695 spin_unlock(&tsk->sighand->siglock);
696 posixtimer_rearm(info);
697 spin_lock(&tsk->sighand->siglock);
699 /* Don't expose the si_sys_private value to userspace */
700 info->si_sys_private = 0;
705 EXPORT_SYMBOL_GPL(dequeue_signal);
707 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
709 struct task_struct *tsk = current;
710 struct sigpending *pending = &tsk->pending;
711 struct sigqueue *q, *sync = NULL;
714 * Might a synchronous signal be in the queue?
716 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
720 * Return the first synchronous signal in the queue.
722 list_for_each_entry(q, &pending->list, list) {
723 /* Synchronous signals have a positive si_code */
724 if ((q->info.si_code > SI_USER) &&
725 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
733 * Check if there is another siginfo for the same signal.
735 list_for_each_entry_continue(q, &pending->list, list) {
736 if (q->info.si_signo == sync->info.si_signo)
740 sigdelset(&pending->signal, sync->info.si_signo);
743 list_del_init(&sync->list);
744 copy_siginfo(info, &sync->info);
745 __sigqueue_free(sync);
746 return info->si_signo;
750 * Tell a process that it has a new active signal..
752 * NOTE! we rely on the previous spin_lock to
753 * lock interrupts for us! We can only be called with
754 * "siglock" held, and the local interrupt must
755 * have been disabled when that got acquired!
757 * No need to set need_resched since signal event passing
758 * goes through ->blocked
760 void signal_wake_up_state(struct task_struct *t, unsigned int state)
762 set_tsk_thread_flag(t, TIF_SIGPENDING);
764 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
765 * case. We don't check t->state here because there is a race with it
766 * executing another processor and just now entering stopped state.
767 * By using wake_up_state, we ensure the process will wake up and
768 * handle its death signal.
770 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
775 * Remove signals in mask from the pending set and queue.
776 * Returns 1 if any signals were found.
778 * All callers must be holding the siglock.
780 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
782 struct sigqueue *q, *n;
785 sigandsets(&m, mask, &s->signal);
786 if (sigisemptyset(&m))
789 sigandnsets(&s->signal, &s->signal, mask);
790 list_for_each_entry_safe(q, n, &s->list, list) {
791 if (sigismember(mask, q->info.si_signo)) {
792 list_del_init(&q->list);
798 static inline int is_si_special(const struct kernel_siginfo *info)
800 return info <= SEND_SIG_PRIV;
803 static inline bool si_fromuser(const struct kernel_siginfo *info)
805 return info == SEND_SIG_NOINFO ||
806 (!is_si_special(info) && SI_FROMUSER(info));
810 * called with RCU read lock from check_kill_permission()
812 static bool kill_ok_by_cred(struct task_struct *t)
814 const struct cred *cred = current_cred();
815 const struct cred *tcred = __task_cred(t);
817 return uid_eq(cred->euid, tcred->suid) ||
818 uid_eq(cred->euid, tcred->uid) ||
819 uid_eq(cred->uid, tcred->suid) ||
820 uid_eq(cred->uid, tcred->uid) ||
821 ns_capable(tcred->user_ns, CAP_KILL);
825 * Bad permissions for sending the signal
826 * - the caller must hold the RCU read lock
828 static int check_kill_permission(int sig, struct kernel_siginfo *info,
829 struct task_struct *t)
834 if (!valid_signal(sig))
837 if (!si_fromuser(info))
840 error = audit_signal_info(sig, t); /* Let audit system see the signal */
844 if (!same_thread_group(current, t) &&
845 !kill_ok_by_cred(t)) {
848 sid = task_session(t);
850 * We don't return the error if sid == NULL. The
851 * task was unhashed, the caller must notice this.
853 if (!sid || sid == task_session(current))
861 return security_task_kill(t, info, sig, NULL);
865 * ptrace_trap_notify - schedule trap to notify ptracer
866 * @t: tracee wanting to notify tracer
868 * This function schedules sticky ptrace trap which is cleared on the next
869 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
872 * If @t is running, STOP trap will be taken. If trapped for STOP and
873 * ptracer is listening for events, tracee is woken up so that it can
874 * re-trap for the new event. If trapped otherwise, STOP trap will be
875 * eventually taken without returning to userland after the existing traps
876 * are finished by PTRACE_CONT.
879 * Must be called with @task->sighand->siglock held.
881 static void ptrace_trap_notify(struct task_struct *t)
883 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
884 assert_spin_locked(&t->sighand->siglock);
886 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
887 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
891 * Handle magic process-wide effects of stop/continue signals. Unlike
892 * the signal actions, these happen immediately at signal-generation
893 * time regardless of blocking, ignoring, or handling. This does the
894 * actual continuing for SIGCONT, but not the actual stopping for stop
895 * signals. The process stop is done as a signal action for SIG_DFL.
897 * Returns true if the signal should be actually delivered, otherwise
898 * it should be dropped.
900 static bool prepare_signal(int sig, struct task_struct *p, bool force)
902 struct signal_struct *signal = p->signal;
903 struct task_struct *t;
906 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
907 if (!(signal->flags & SIGNAL_GROUP_EXIT))
908 return sig == SIGKILL;
910 * The process is in the middle of dying, nothing to do.
912 } else if (sig_kernel_stop(sig)) {
914 * This is a stop signal. Remove SIGCONT from all queues.
916 siginitset(&flush, sigmask(SIGCONT));
917 flush_sigqueue_mask(&flush, &signal->shared_pending);
918 for_each_thread(p, t)
919 flush_sigqueue_mask(&flush, &t->pending);
920 } else if (sig == SIGCONT) {
923 * Remove all stop signals from all queues, wake all threads.
925 siginitset(&flush, SIG_KERNEL_STOP_MASK);
926 flush_sigqueue_mask(&flush, &signal->shared_pending);
927 for_each_thread(p, t) {
928 flush_sigqueue_mask(&flush, &t->pending);
929 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
930 if (likely(!(t->ptrace & PT_SEIZED)))
931 wake_up_state(t, __TASK_STOPPED);
933 ptrace_trap_notify(t);
937 * Notify the parent with CLD_CONTINUED if we were stopped.
939 * If we were in the middle of a group stop, we pretend it
940 * was already finished, and then continued. Since SIGCHLD
941 * doesn't queue we report only CLD_STOPPED, as if the next
942 * CLD_CONTINUED was dropped.
945 if (signal->flags & SIGNAL_STOP_STOPPED)
946 why |= SIGNAL_CLD_CONTINUED;
947 else if (signal->group_stop_count)
948 why |= SIGNAL_CLD_STOPPED;
952 * The first thread which returns from do_signal_stop()
953 * will take ->siglock, notice SIGNAL_CLD_MASK, and
954 * notify its parent. See get_signal().
956 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
957 signal->group_stop_count = 0;
958 signal->group_exit_code = 0;
962 return !sig_ignored(p, sig, force);
966 * Test if P wants to take SIG. After we've checked all threads with this,
967 * it's equivalent to finding no threads not blocking SIG. Any threads not
968 * blocking SIG were ruled out because they are not running and already
969 * have pending signals. Such threads will dequeue from the shared queue
970 * as soon as they're available, so putting the signal on the shared queue
971 * will be equivalent to sending it to one such thread.
973 static inline bool wants_signal(int sig, struct task_struct *p)
975 if (sigismember(&p->blocked, sig))
978 if (p->flags & PF_EXITING)
984 if (task_is_stopped_or_traced(p))
987 return task_curr(p) || !signal_pending(p);
990 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
992 struct signal_struct *signal = p->signal;
993 struct task_struct *t;
996 * Now find a thread we can wake up to take the signal off the queue.
998 * If the main thread wants the signal, it gets first crack.
999 * Probably the least surprising to the average bear.
1001 if (wants_signal(sig, p))
1003 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1005 * There is just one thread and it does not need to be woken.
1006 * It will dequeue unblocked signals before it runs again.
1011 * Otherwise try to find a suitable thread.
1013 t = signal->curr_target;
1014 while (!wants_signal(sig, t)) {
1016 if (t == signal->curr_target)
1018 * No thread needs to be woken.
1019 * Any eligible threads will see
1020 * the signal in the queue soon.
1024 signal->curr_target = t;
1028 * Found a killable thread. If the signal will be fatal,
1029 * then start taking the whole group down immediately.
1031 if (sig_fatal(p, sig) &&
1032 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1033 !sigismember(&t->real_blocked, sig) &&
1034 (sig == SIGKILL || !p->ptrace)) {
1036 * This signal will be fatal to the whole group.
1038 if (!sig_kernel_coredump(sig)) {
1040 * Start a group exit and wake everybody up.
1041 * This way we don't have other threads
1042 * running and doing things after a slower
1043 * thread has the fatal signal pending.
1045 signal->flags = SIGNAL_GROUP_EXIT;
1046 signal->group_exit_code = sig;
1047 signal->group_stop_count = 0;
1050 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1051 sigaddset(&t->pending.signal, SIGKILL);
1052 signal_wake_up(t, 1);
1053 } while_each_thread(p, t);
1059 * The signal is already in the shared-pending queue.
1060 * Tell the chosen thread to wake up and dequeue it.
1062 signal_wake_up(t, sig == SIGKILL);
1066 static inline bool legacy_queue(struct sigpending *signals, int sig)
1068 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1071 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1072 enum pid_type type, bool force)
1074 struct sigpending *pending;
1076 int override_rlimit;
1077 int ret = 0, result;
1079 assert_spin_locked(&t->sighand->siglock);
1081 result = TRACE_SIGNAL_IGNORED;
1082 if (!prepare_signal(sig, t, force))
1085 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1087 * Short-circuit ignored signals and support queuing
1088 * exactly one non-rt signal, so that we can get more
1089 * detailed information about the cause of the signal.
1091 result = TRACE_SIGNAL_ALREADY_PENDING;
1092 if (legacy_queue(pending, sig))
1095 result = TRACE_SIGNAL_DELIVERED;
1097 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1099 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1103 * Real-time signals must be queued if sent by sigqueue, or
1104 * some other real-time mechanism. It is implementation
1105 * defined whether kill() does so. We attempt to do so, on
1106 * the principle of least surprise, but since kill is not
1107 * allowed to fail with EAGAIN when low on memory we just
1108 * make sure at least one signal gets delivered and don't
1109 * pass on the info struct.
1112 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1114 override_rlimit = 0;
1116 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
1118 list_add_tail(&q->list, &pending->list);
1119 switch ((unsigned long) info) {
1120 case (unsigned long) SEND_SIG_NOINFO:
1121 clear_siginfo(&q->info);
1122 q->info.si_signo = sig;
1123 q->info.si_errno = 0;
1124 q->info.si_code = SI_USER;
1125 q->info.si_pid = task_tgid_nr_ns(current,
1126 task_active_pid_ns(t));
1129 from_kuid_munged(task_cred_xxx(t, user_ns),
1133 case (unsigned long) SEND_SIG_PRIV:
1134 clear_siginfo(&q->info);
1135 q->info.si_signo = sig;
1136 q->info.si_errno = 0;
1137 q->info.si_code = SI_KERNEL;
1142 copy_siginfo(&q->info, info);
1145 } else if (!is_si_special(info) &&
1146 sig >= SIGRTMIN && info->si_code != SI_USER) {
1148 * Queue overflow, abort. We may abort if the
1149 * signal was rt and sent by user using something
1150 * other than kill().
1152 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1157 * This is a silent loss of information. We still
1158 * send the signal, but the *info bits are lost.
1160 result = TRACE_SIGNAL_LOSE_INFO;
1164 signalfd_notify(t, sig);
1165 sigaddset(&pending->signal, sig);
1167 /* Let multiprocess signals appear after on-going forks */
1168 if (type > PIDTYPE_TGID) {
1169 struct multiprocess_signals *delayed;
1170 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1171 sigset_t *signal = &delayed->signal;
1172 /* Can't queue both a stop and a continue signal */
1174 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1175 else if (sig_kernel_stop(sig))
1176 sigdelset(signal, SIGCONT);
1177 sigaddset(signal, sig);
1181 complete_signal(sig, t, type);
1183 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1187 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1190 switch (siginfo_layout(info->si_signo, info->si_code)) {
1199 case SIL_FAULT_MCEERR:
1200 case SIL_FAULT_BNDERR:
1201 case SIL_FAULT_PKUERR:
1209 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1212 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1215 if (info == SEND_SIG_NOINFO) {
1216 /* Force if sent from an ancestor pid namespace */
1217 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1218 } else if (info == SEND_SIG_PRIV) {
1219 /* Don't ignore kernel generated signals */
1221 } else if (has_si_pid_and_uid(info)) {
1222 /* SIGKILL and SIGSTOP is special or has ids */
1223 struct user_namespace *t_user_ns;
1226 t_user_ns = task_cred_xxx(t, user_ns);
1227 if (current_user_ns() != t_user_ns) {
1228 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1229 info->si_uid = from_kuid_munged(t_user_ns, uid);
1233 /* A kernel generated signal? */
1234 force = (info->si_code == SI_KERNEL);
1236 /* From an ancestor pid namespace? */
1237 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1242 return __send_signal(sig, info, t, type, force);
1245 static void print_fatal_signal(int signr)
1247 struct pt_regs *regs = signal_pt_regs();
1248 pr_info("potentially unexpected fatal signal %d.\n", signr);
1250 #if defined(__i386__) && !defined(__arch_um__)
1251 pr_info("code at %08lx: ", regs->ip);
1254 for (i = 0; i < 16; i++) {
1257 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1259 pr_cont("%02x ", insn);
1269 static int __init setup_print_fatal_signals(char *str)
1271 get_option (&str, &print_fatal_signals);
1276 __setup("print-fatal-signals=", setup_print_fatal_signals);
1279 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1281 return send_signal(sig, info, p, PIDTYPE_TGID);
1284 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1287 unsigned long flags;
1290 if (lock_task_sighand(p, &flags)) {
1291 ret = send_signal(sig, info, p, type);
1292 unlock_task_sighand(p, &flags);
1299 * Force a signal that the process can't ignore: if necessary
1300 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1302 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1303 * since we do not want to have a signal handler that was blocked
1304 * be invoked when user space had explicitly blocked it.
1306 * We don't want to have recursive SIGSEGV's etc, for example,
1307 * that is why we also clear SIGNAL_UNKILLABLE.
1310 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t)
1312 unsigned long int flags;
1313 int ret, blocked, ignored;
1314 struct k_sigaction *action;
1315 int sig = info->si_signo;
1317 spin_lock_irqsave(&t->sighand->siglock, flags);
1318 action = &t->sighand->action[sig-1];
1319 ignored = action->sa.sa_handler == SIG_IGN;
1320 blocked = sigismember(&t->blocked, sig);
1321 if (blocked || ignored) {
1322 action->sa.sa_handler = SIG_DFL;
1324 sigdelset(&t->blocked, sig);
1325 recalc_sigpending_and_wake(t);
1329 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1330 * debugging to leave init killable.
1332 if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
1333 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1334 ret = send_signal(sig, info, t, PIDTYPE_PID);
1335 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1340 int force_sig_info(struct kernel_siginfo *info)
1342 return force_sig_info_to_task(info, current);
1346 * Nuke all other threads in the group.
1348 int zap_other_threads(struct task_struct *p)
1350 struct task_struct *t = p;
1353 p->signal->group_stop_count = 0;
1355 while_each_thread(p, t) {
1356 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1359 /* Don't bother with already dead threads */
1362 sigaddset(&t->pending.signal, SIGKILL);
1363 signal_wake_up(t, 1);
1369 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1370 unsigned long *flags)
1372 struct sighand_struct *sighand;
1376 sighand = rcu_dereference(tsk->sighand);
1377 if (unlikely(sighand == NULL))
1381 * This sighand can be already freed and even reused, but
1382 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1383 * initializes ->siglock: this slab can't go away, it has
1384 * the same object type, ->siglock can't be reinitialized.
1386 * We need to ensure that tsk->sighand is still the same
1387 * after we take the lock, we can race with de_thread() or
1388 * __exit_signal(). In the latter case the next iteration
1389 * must see ->sighand == NULL.
1391 spin_lock_irqsave(&sighand->siglock, *flags);
1392 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1394 spin_unlock_irqrestore(&sighand->siglock, *flags);
1402 * send signal info to all the members of a group
1404 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1405 struct task_struct *p, enum pid_type type)
1410 ret = check_kill_permission(sig, info, p);
1414 ret = do_send_sig_info(sig, info, p, type);
1420 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1421 * control characters do (^C, ^Z etc)
1422 * - the caller must hold at least a readlock on tasklist_lock
1424 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1426 struct task_struct *p = NULL;
1427 int retval, success;
1431 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1432 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1435 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1436 return success ? 0 : retval;
1439 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1442 struct task_struct *p;
1446 p = pid_task(pid, PIDTYPE_PID);
1448 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1450 if (likely(!p || error != -ESRCH))
1454 * The task was unhashed in between, try again. If it
1455 * is dead, pid_task() will return NULL, if we race with
1456 * de_thread() it will find the new leader.
1461 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1465 error = kill_pid_info(sig, info, find_vpid(pid));
1470 static inline bool kill_as_cred_perm(const struct cred *cred,
1471 struct task_struct *target)
1473 const struct cred *pcred = __task_cred(target);
1475 return uid_eq(cred->euid, pcred->suid) ||
1476 uid_eq(cred->euid, pcred->uid) ||
1477 uid_eq(cred->uid, pcred->suid) ||
1478 uid_eq(cred->uid, pcred->uid);
1482 * The usb asyncio usage of siginfo is wrong. The glibc support
1483 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1484 * AKA after the generic fields:
1485 * kernel_pid_t si_pid;
1486 * kernel_uid32_t si_uid;
1487 * sigval_t si_value;
1489 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1490 * after the generic fields is:
1491 * void __user *si_addr;
1493 * This is a practical problem when there is a 64bit big endian kernel
1494 * and a 32bit userspace. As the 32bit address will encoded in the low
1495 * 32bits of the pointer. Those low 32bits will be stored at higher
1496 * address than appear in a 32 bit pointer. So userspace will not
1497 * see the address it was expecting for it's completions.
1499 * There is nothing in the encoding that can allow
1500 * copy_siginfo_to_user32 to detect this confusion of formats, so
1501 * handle this by requiring the caller of kill_pid_usb_asyncio to
1502 * notice when this situration takes place and to store the 32bit
1503 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1506 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1507 struct pid *pid, const struct cred *cred)
1509 struct kernel_siginfo info;
1510 struct task_struct *p;
1511 unsigned long flags;
1514 if (!valid_signal(sig))
1517 clear_siginfo(&info);
1518 info.si_signo = sig;
1519 info.si_errno = errno;
1520 info.si_code = SI_ASYNCIO;
1521 *((sigval_t *)&info.si_pid) = addr;
1524 p = pid_task(pid, PIDTYPE_PID);
1529 if (!kill_as_cred_perm(cred, p)) {
1533 ret = security_task_kill(p, &info, sig, cred);
1538 if (lock_task_sighand(p, &flags)) {
1539 ret = __send_signal(sig, &info, p, PIDTYPE_TGID, false);
1540 unlock_task_sighand(p, &flags);
1548 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1551 * kill_something_info() interprets pid in interesting ways just like kill(2).
1553 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1554 * is probably wrong. Should make it like BSD or SYSV.
1557 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1562 return kill_proc_info(sig, info, pid);
1564 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1568 read_lock(&tasklist_lock);
1570 ret = __kill_pgrp_info(sig, info,
1571 pid ? find_vpid(-pid) : task_pgrp(current));
1573 int retval = 0, count = 0;
1574 struct task_struct * p;
1576 for_each_process(p) {
1577 if (task_pid_vnr(p) > 1 &&
1578 !same_thread_group(p, current)) {
1579 int err = group_send_sig_info(sig, info, p,
1586 ret = count ? retval : -ESRCH;
1588 read_unlock(&tasklist_lock);
1594 * These are for backward compatibility with the rest of the kernel source.
1597 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1600 * Make sure legacy kernel users don't send in bad values
1601 * (normal paths check this in check_kill_permission).
1603 if (!valid_signal(sig))
1606 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1608 EXPORT_SYMBOL(send_sig_info);
1610 #define __si_special(priv) \
1611 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1614 send_sig(int sig, struct task_struct *p, int priv)
1616 return send_sig_info(sig, __si_special(priv), p);
1618 EXPORT_SYMBOL(send_sig);
1620 void force_sig(int sig)
1622 struct kernel_siginfo info;
1624 clear_siginfo(&info);
1625 info.si_signo = sig;
1627 info.si_code = SI_KERNEL;
1630 force_sig_info(&info);
1632 EXPORT_SYMBOL(force_sig);
1635 * When things go south during signal handling, we
1636 * will force a SIGSEGV. And if the signal that caused
1637 * the problem was already a SIGSEGV, we'll want to
1638 * make sure we don't even try to deliver the signal..
1640 void force_sigsegv(int sig)
1642 struct task_struct *p = current;
1644 if (sig == SIGSEGV) {
1645 unsigned long flags;
1646 spin_lock_irqsave(&p->sighand->siglock, flags);
1647 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1648 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1653 int force_sig_fault_to_task(int sig, int code, void __user *addr
1654 ___ARCH_SI_TRAPNO(int trapno)
1655 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1656 , struct task_struct *t)
1658 struct kernel_siginfo info;
1660 clear_siginfo(&info);
1661 info.si_signo = sig;
1663 info.si_code = code;
1664 info.si_addr = addr;
1665 #ifdef __ARCH_SI_TRAPNO
1666 info.si_trapno = trapno;
1670 info.si_flags = flags;
1673 return force_sig_info_to_task(&info, t);
1676 int force_sig_fault(int sig, int code, void __user *addr
1677 ___ARCH_SI_TRAPNO(int trapno)
1678 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1680 return force_sig_fault_to_task(sig, code, addr
1681 ___ARCH_SI_TRAPNO(trapno)
1682 ___ARCH_SI_IA64(imm, flags, isr), current);
1685 int send_sig_fault(int sig, int code, void __user *addr
1686 ___ARCH_SI_TRAPNO(int trapno)
1687 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1688 , struct task_struct *t)
1690 struct kernel_siginfo info;
1692 clear_siginfo(&info);
1693 info.si_signo = sig;
1695 info.si_code = code;
1696 info.si_addr = addr;
1697 #ifdef __ARCH_SI_TRAPNO
1698 info.si_trapno = trapno;
1702 info.si_flags = flags;
1705 return send_sig_info(info.si_signo, &info, t);
1708 int force_sig_mceerr(int code, void __user *addr, short lsb)
1710 struct kernel_siginfo info;
1712 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1713 clear_siginfo(&info);
1714 info.si_signo = SIGBUS;
1716 info.si_code = code;
1717 info.si_addr = addr;
1718 info.si_addr_lsb = lsb;
1719 return force_sig_info(&info);
1722 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1724 struct kernel_siginfo info;
1726 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1727 clear_siginfo(&info);
1728 info.si_signo = SIGBUS;
1730 info.si_code = code;
1731 info.si_addr = addr;
1732 info.si_addr_lsb = lsb;
1733 return send_sig_info(info.si_signo, &info, t);
1735 EXPORT_SYMBOL(send_sig_mceerr);
1737 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1739 struct kernel_siginfo info;
1741 clear_siginfo(&info);
1742 info.si_signo = SIGSEGV;
1744 info.si_code = SEGV_BNDERR;
1745 info.si_addr = addr;
1746 info.si_lower = lower;
1747 info.si_upper = upper;
1748 return force_sig_info(&info);
1752 int force_sig_pkuerr(void __user *addr, u32 pkey)
1754 struct kernel_siginfo info;
1756 clear_siginfo(&info);
1757 info.si_signo = SIGSEGV;
1759 info.si_code = SEGV_PKUERR;
1760 info.si_addr = addr;
1761 info.si_pkey = pkey;
1762 return force_sig_info(&info);
1766 /* For the crazy architectures that include trap information in
1767 * the errno field, instead of an actual errno value.
1769 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1771 struct kernel_siginfo info;
1773 clear_siginfo(&info);
1774 info.si_signo = SIGTRAP;
1775 info.si_errno = errno;
1776 info.si_code = TRAP_HWBKPT;
1777 info.si_addr = addr;
1778 return force_sig_info(&info);
1781 int kill_pgrp(struct pid *pid, int sig, int priv)
1785 read_lock(&tasklist_lock);
1786 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1787 read_unlock(&tasklist_lock);
1791 EXPORT_SYMBOL(kill_pgrp);
1793 int kill_pid(struct pid *pid, int sig, int priv)
1795 return kill_pid_info(sig, __si_special(priv), pid);
1797 EXPORT_SYMBOL(kill_pid);
1800 * These functions support sending signals using preallocated sigqueue
1801 * structures. This is needed "because realtime applications cannot
1802 * afford to lose notifications of asynchronous events, like timer
1803 * expirations or I/O completions". In the case of POSIX Timers
1804 * we allocate the sigqueue structure from the timer_create. If this
1805 * allocation fails we are able to report the failure to the application
1806 * with an EAGAIN error.
1808 struct sigqueue *sigqueue_alloc(void)
1810 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1813 q->flags |= SIGQUEUE_PREALLOC;
1818 void sigqueue_free(struct sigqueue *q)
1820 unsigned long flags;
1821 spinlock_t *lock = ¤t->sighand->siglock;
1823 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1825 * We must hold ->siglock while testing q->list
1826 * to serialize with collect_signal() or with
1827 * __exit_signal()->flush_sigqueue().
1829 spin_lock_irqsave(lock, flags);
1830 q->flags &= ~SIGQUEUE_PREALLOC;
1832 * If it is queued it will be freed when dequeued,
1833 * like the "regular" sigqueue.
1835 if (!list_empty(&q->list))
1837 spin_unlock_irqrestore(lock, flags);
1843 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1845 int sig = q->info.si_signo;
1846 struct sigpending *pending;
1847 struct task_struct *t;
1848 unsigned long flags;
1851 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1855 t = pid_task(pid, type);
1856 if (!t || !likely(lock_task_sighand(t, &flags)))
1859 ret = 1; /* the signal is ignored */
1860 result = TRACE_SIGNAL_IGNORED;
1861 if (!prepare_signal(sig, t, false))
1865 if (unlikely(!list_empty(&q->list))) {
1867 * If an SI_TIMER entry is already queue just increment
1868 * the overrun count.
1870 BUG_ON(q->info.si_code != SI_TIMER);
1871 q->info.si_overrun++;
1872 result = TRACE_SIGNAL_ALREADY_PENDING;
1875 q->info.si_overrun = 0;
1877 signalfd_notify(t, sig);
1878 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1879 list_add_tail(&q->list, &pending->list);
1880 sigaddset(&pending->signal, sig);
1881 complete_signal(sig, t, type);
1882 result = TRACE_SIGNAL_DELIVERED;
1884 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
1885 unlock_task_sighand(t, &flags);
1891 static void do_notify_pidfd(struct task_struct *task)
1895 WARN_ON(task->exit_state == 0);
1896 pid = task_pid(task);
1897 wake_up_all(&pid->wait_pidfd);
1901 * Let a parent know about the death of a child.
1902 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1904 * Returns true if our parent ignored us and so we've switched to
1907 bool do_notify_parent(struct task_struct *tsk, int sig)
1909 struct kernel_siginfo info;
1910 unsigned long flags;
1911 struct sighand_struct *psig;
1912 bool autoreap = false;
1917 /* do_notify_parent_cldstop should have been called instead. */
1918 BUG_ON(task_is_stopped_or_traced(tsk));
1920 BUG_ON(!tsk->ptrace &&
1921 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1923 /* Wake up all pidfd waiters */
1924 do_notify_pidfd(tsk);
1926 if (sig != SIGCHLD) {
1928 * This is only possible if parent == real_parent.
1929 * Check if it has changed security domain.
1931 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
1935 clear_siginfo(&info);
1936 info.si_signo = sig;
1939 * We are under tasklist_lock here so our parent is tied to
1940 * us and cannot change.
1942 * task_active_pid_ns will always return the same pid namespace
1943 * until a task passes through release_task.
1945 * write_lock() currently calls preempt_disable() which is the
1946 * same as rcu_read_lock(), but according to Oleg, this is not
1947 * correct to rely on this
1950 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1951 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1955 task_cputime(tsk, &utime, &stime);
1956 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
1957 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
1959 info.si_status = tsk->exit_code & 0x7f;
1960 if (tsk->exit_code & 0x80)
1961 info.si_code = CLD_DUMPED;
1962 else if (tsk->exit_code & 0x7f)
1963 info.si_code = CLD_KILLED;
1965 info.si_code = CLD_EXITED;
1966 info.si_status = tsk->exit_code >> 8;
1969 psig = tsk->parent->sighand;
1970 spin_lock_irqsave(&psig->siglock, flags);
1971 if (!tsk->ptrace && sig == SIGCHLD &&
1972 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1973 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1975 * We are exiting and our parent doesn't care. POSIX.1
1976 * defines special semantics for setting SIGCHLD to SIG_IGN
1977 * or setting the SA_NOCLDWAIT flag: we should be reaped
1978 * automatically and not left for our parent's wait4 call.
1979 * Rather than having the parent do it as a magic kind of
1980 * signal handler, we just set this to tell do_exit that we
1981 * can be cleaned up without becoming a zombie. Note that
1982 * we still call __wake_up_parent in this case, because a
1983 * blocked sys_wait4 might now return -ECHILD.
1985 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1986 * is implementation-defined: we do (if you don't want
1987 * it, just use SIG_IGN instead).
1990 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1994 * Send with __send_signal as si_pid and si_uid are in the
1995 * parent's namespaces.
1997 if (valid_signal(sig) && sig)
1998 __send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false);
1999 __wake_up_parent(tsk, tsk->parent);
2000 spin_unlock_irqrestore(&psig->siglock, flags);
2006 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2007 * @tsk: task reporting the state change
2008 * @for_ptracer: the notification is for ptracer
2009 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2011 * Notify @tsk's parent that the stopped/continued state has changed. If
2012 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2013 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2016 * Must be called with tasklist_lock at least read locked.
2018 static void do_notify_parent_cldstop(struct task_struct *tsk,
2019 bool for_ptracer, int why)
2021 struct kernel_siginfo info;
2022 unsigned long flags;
2023 struct task_struct *parent;
2024 struct sighand_struct *sighand;
2028 parent = tsk->parent;
2030 tsk = tsk->group_leader;
2031 parent = tsk->real_parent;
2034 clear_siginfo(&info);
2035 info.si_signo = SIGCHLD;
2038 * see comment in do_notify_parent() about the following 4 lines
2041 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2042 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2045 task_cputime(tsk, &utime, &stime);
2046 info.si_utime = nsec_to_clock_t(utime);
2047 info.si_stime = nsec_to_clock_t(stime);
2052 info.si_status = SIGCONT;
2055 info.si_status = tsk->signal->group_exit_code & 0x7f;
2058 info.si_status = tsk->exit_code & 0x7f;
2064 sighand = parent->sighand;
2065 spin_lock_irqsave(&sighand->siglock, flags);
2066 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2067 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2068 __group_send_sig_info(SIGCHLD, &info, parent);
2070 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2072 __wake_up_parent(tsk, parent);
2073 spin_unlock_irqrestore(&sighand->siglock, flags);
2076 static inline bool may_ptrace_stop(void)
2078 if (!likely(current->ptrace))
2081 * Are we in the middle of do_coredump?
2082 * If so and our tracer is also part of the coredump stopping
2083 * is a deadlock situation, and pointless because our tracer
2084 * is dead so don't allow us to stop.
2085 * If SIGKILL was already sent before the caller unlocked
2086 * ->siglock we must see ->core_state != NULL. Otherwise it
2087 * is safe to enter schedule().
2089 * This is almost outdated, a task with the pending SIGKILL can't
2090 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2091 * after SIGKILL was already dequeued.
2093 if (unlikely(current->mm->core_state) &&
2094 unlikely(current->mm == current->parent->mm))
2102 * This must be called with current->sighand->siglock held.
2104 * This should be the path for all ptrace stops.
2105 * We always set current->last_siginfo while stopped here.
2106 * That makes it a way to test a stopped process for
2107 * being ptrace-stopped vs being job-control-stopped.
2109 * If we actually decide not to stop at all because the tracer
2110 * is gone, we keep current->exit_code unless clear_code.
2112 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2113 __releases(¤t->sighand->siglock)
2114 __acquires(¤t->sighand->siglock)
2116 bool gstop_done = false;
2118 if (arch_ptrace_stop_needed(exit_code, info)) {
2120 * The arch code has something special to do before a
2121 * ptrace stop. This is allowed to block, e.g. for faults
2122 * on user stack pages. We can't keep the siglock while
2123 * calling arch_ptrace_stop, so we must release it now.
2124 * To preserve proper semantics, we must do this before
2125 * any signal bookkeeping like checking group_stop_count.
2127 spin_unlock_irq(¤t->sighand->siglock);
2128 arch_ptrace_stop(exit_code, info);
2129 spin_lock_irq(¤t->sighand->siglock);
2133 * schedule() will not sleep if there is a pending signal that
2134 * can awaken the task.
2136 set_special_state(TASK_TRACED);
2139 * We're committing to trapping. TRACED should be visible before
2140 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2141 * Also, transition to TRACED and updates to ->jobctl should be
2142 * atomic with respect to siglock and should be done after the arch
2143 * hook as siglock is released and regrabbed across it.
2148 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2150 * set_current_state() smp_wmb();
2152 * wait_task_stopped()
2153 * task_stopped_code()
2154 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2158 current->last_siginfo = info;
2159 current->exit_code = exit_code;
2162 * If @why is CLD_STOPPED, we're trapping to participate in a group
2163 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2164 * across siglock relocks since INTERRUPT was scheduled, PENDING
2165 * could be clear now. We act as if SIGCONT is received after
2166 * TASK_TRACED is entered - ignore it.
2168 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2169 gstop_done = task_participate_group_stop(current);
2171 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2172 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2173 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2174 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2176 /* entering a trap, clear TRAPPING */
2177 task_clear_jobctl_trapping(current);
2179 spin_unlock_irq(¤t->sighand->siglock);
2180 read_lock(&tasklist_lock);
2181 if (may_ptrace_stop()) {
2183 * Notify parents of the stop.
2185 * While ptraced, there are two parents - the ptracer and
2186 * the real_parent of the group_leader. The ptracer should
2187 * know about every stop while the real parent is only
2188 * interested in the completion of group stop. The states
2189 * for the two don't interact with each other. Notify
2190 * separately unless they're gonna be duplicates.
2192 do_notify_parent_cldstop(current, true, why);
2193 if (gstop_done && ptrace_reparented(current))
2194 do_notify_parent_cldstop(current, false, why);
2197 * Don't want to allow preemption here, because
2198 * sys_ptrace() needs this task to be inactive.
2200 * XXX: implement read_unlock_no_resched().
2203 read_unlock(&tasklist_lock);
2204 cgroup_enter_frozen();
2205 preempt_enable_no_resched();
2206 freezable_schedule();
2207 cgroup_leave_frozen(true);
2210 * By the time we got the lock, our tracer went away.
2211 * Don't drop the lock yet, another tracer may come.
2213 * If @gstop_done, the ptracer went away between group stop
2214 * completion and here. During detach, it would have set
2215 * JOBCTL_STOP_PENDING on us and we'll re-enter
2216 * TASK_STOPPED in do_signal_stop() on return, so notifying
2217 * the real parent of the group stop completion is enough.
2220 do_notify_parent_cldstop(current, false, why);
2222 /* tasklist protects us from ptrace_freeze_traced() */
2223 __set_current_state(TASK_RUNNING);
2225 current->exit_code = 0;
2226 read_unlock(&tasklist_lock);
2230 * We are back. Now reacquire the siglock before touching
2231 * last_siginfo, so that we are sure to have synchronized with
2232 * any signal-sending on another CPU that wants to examine it.
2234 spin_lock_irq(¤t->sighand->siglock);
2235 current->last_siginfo = NULL;
2237 /* LISTENING can be set only during STOP traps, clear it */
2238 current->jobctl &= ~JOBCTL_LISTENING;
2241 * Queued signals ignored us while we were stopped for tracing.
2242 * So check for any that we should take before resuming user mode.
2243 * This sets TIF_SIGPENDING, but never clears it.
2245 recalc_sigpending_tsk(current);
2248 static void ptrace_do_notify(int signr, int exit_code, int why)
2250 kernel_siginfo_t info;
2252 clear_siginfo(&info);
2253 info.si_signo = signr;
2254 info.si_code = exit_code;
2255 info.si_pid = task_pid_vnr(current);
2256 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2258 /* Let the debugger run. */
2259 ptrace_stop(exit_code, why, 1, &info);
2262 void ptrace_notify(int exit_code)
2264 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2265 if (unlikely(current->task_works))
2268 spin_lock_irq(¤t->sighand->siglock);
2269 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2270 spin_unlock_irq(¤t->sighand->siglock);
2274 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2275 * @signr: signr causing group stop if initiating
2277 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2278 * and participate in it. If already set, participate in the existing
2279 * group stop. If participated in a group stop (and thus slept), %true is
2280 * returned with siglock released.
2282 * If ptraced, this function doesn't handle stop itself. Instead,
2283 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2284 * untouched. The caller must ensure that INTERRUPT trap handling takes
2285 * places afterwards.
2288 * Must be called with @current->sighand->siglock held, which is released
2292 * %false if group stop is already cancelled or ptrace trap is scheduled.
2293 * %true if participated in group stop.
2295 static bool do_signal_stop(int signr)
2296 __releases(¤t->sighand->siglock)
2298 struct signal_struct *sig = current->signal;
2300 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2301 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2302 struct task_struct *t;
2304 /* signr will be recorded in task->jobctl for retries */
2305 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2307 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2308 unlikely(signal_group_exit(sig)))
2311 * There is no group stop already in progress. We must
2314 * While ptraced, a task may be resumed while group stop is
2315 * still in effect and then receive a stop signal and
2316 * initiate another group stop. This deviates from the
2317 * usual behavior as two consecutive stop signals can't
2318 * cause two group stops when !ptraced. That is why we
2319 * also check !task_is_stopped(t) below.
2321 * The condition can be distinguished by testing whether
2322 * SIGNAL_STOP_STOPPED is already set. Don't generate
2323 * group_exit_code in such case.
2325 * This is not necessary for SIGNAL_STOP_CONTINUED because
2326 * an intervening stop signal is required to cause two
2327 * continued events regardless of ptrace.
2329 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2330 sig->group_exit_code = signr;
2332 sig->group_stop_count = 0;
2334 if (task_set_jobctl_pending(current, signr | gstop))
2335 sig->group_stop_count++;
2338 while_each_thread(current, t) {
2340 * Setting state to TASK_STOPPED for a group
2341 * stop is always done with the siglock held,
2342 * so this check has no races.
2344 if (!task_is_stopped(t) &&
2345 task_set_jobctl_pending(t, signr | gstop)) {
2346 sig->group_stop_count++;
2347 if (likely(!(t->ptrace & PT_SEIZED)))
2348 signal_wake_up(t, 0);
2350 ptrace_trap_notify(t);
2355 if (likely(!current->ptrace)) {
2359 * If there are no other threads in the group, or if there
2360 * is a group stop in progress and we are the last to stop,
2361 * report to the parent.
2363 if (task_participate_group_stop(current))
2364 notify = CLD_STOPPED;
2366 set_special_state(TASK_STOPPED);
2367 spin_unlock_irq(¤t->sighand->siglock);
2370 * Notify the parent of the group stop completion. Because
2371 * we're not holding either the siglock or tasklist_lock
2372 * here, ptracer may attach inbetween; however, this is for
2373 * group stop and should always be delivered to the real
2374 * parent of the group leader. The new ptracer will get
2375 * its notification when this task transitions into
2379 read_lock(&tasklist_lock);
2380 do_notify_parent_cldstop(current, false, notify);
2381 read_unlock(&tasklist_lock);
2384 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2385 cgroup_enter_frozen();
2386 freezable_schedule();
2390 * While ptraced, group stop is handled by STOP trap.
2391 * Schedule it and let the caller deal with it.
2393 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2399 * do_jobctl_trap - take care of ptrace jobctl traps
2401 * When PT_SEIZED, it's used for both group stop and explicit
2402 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2403 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2404 * the stop signal; otherwise, %SIGTRAP.
2406 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2407 * number as exit_code and no siginfo.
2410 * Must be called with @current->sighand->siglock held, which may be
2411 * released and re-acquired before returning with intervening sleep.
2413 static void do_jobctl_trap(void)
2415 struct signal_struct *signal = current->signal;
2416 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2418 if (current->ptrace & PT_SEIZED) {
2419 if (!signal->group_stop_count &&
2420 !(signal->flags & SIGNAL_STOP_STOPPED))
2422 WARN_ON_ONCE(!signr);
2423 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2426 WARN_ON_ONCE(!signr);
2427 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2428 current->exit_code = 0;
2433 * do_freezer_trap - handle the freezer jobctl trap
2435 * Puts the task into frozen state, if only the task is not about to quit.
2436 * In this case it drops JOBCTL_TRAP_FREEZE.
2439 * Must be called with @current->sighand->siglock held,
2440 * which is always released before returning.
2442 static void do_freezer_trap(void)
2443 __releases(¤t->sighand->siglock)
2446 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2447 * let's make another loop to give it a chance to be handled.
2448 * In any case, we'll return back.
2450 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2451 JOBCTL_TRAP_FREEZE) {
2452 spin_unlock_irq(¤t->sighand->siglock);
2457 * Now we're sure that there is no pending fatal signal and no
2458 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2459 * immediately (if there is a non-fatal signal pending), and
2460 * put the task into sleep.
2462 __set_current_state(TASK_INTERRUPTIBLE);
2463 clear_thread_flag(TIF_SIGPENDING);
2464 spin_unlock_irq(¤t->sighand->siglock);
2465 cgroup_enter_frozen();
2466 freezable_schedule();
2469 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2472 * We do not check sig_kernel_stop(signr) but set this marker
2473 * unconditionally because we do not know whether debugger will
2474 * change signr. This flag has no meaning unless we are going
2475 * to stop after return from ptrace_stop(). In this case it will
2476 * be checked in do_signal_stop(), we should only stop if it was
2477 * not cleared by SIGCONT while we were sleeping. See also the
2478 * comment in dequeue_signal().
2480 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2481 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2483 /* We're back. Did the debugger cancel the sig? */
2484 signr = current->exit_code;
2488 current->exit_code = 0;
2491 * Update the siginfo structure if the signal has
2492 * changed. If the debugger wanted something
2493 * specific in the siginfo structure then it should
2494 * have updated *info via PTRACE_SETSIGINFO.
2496 if (signr != info->si_signo) {
2497 clear_siginfo(info);
2498 info->si_signo = signr;
2500 info->si_code = SI_USER;
2502 info->si_pid = task_pid_vnr(current->parent);
2503 info->si_uid = from_kuid_munged(current_user_ns(),
2504 task_uid(current->parent));
2508 /* If the (new) signal is now blocked, requeue it. */
2509 if (sigismember(¤t->blocked, signr)) {
2510 send_signal(signr, info, current, PIDTYPE_PID);
2517 bool get_signal(struct ksignal *ksig)
2519 struct sighand_struct *sighand = current->sighand;
2520 struct signal_struct *signal = current->signal;
2523 if (unlikely(uprobe_deny_signal()))
2527 * Do this once, we can't return to user-mode if freezing() == T.
2528 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2529 * thus do not need another check after return.
2534 spin_lock_irq(&sighand->siglock);
2536 * Make sure we can safely read ->jobctl() in task_work add. As Oleg
2539 * It pairs with mb (implied by cmpxchg) before READ_ONCE. So we
2542 * task_work_add: get_signal:
2543 * STORE(task->task_works, new_work); STORE(task->jobctl);
2545 * LOAD(task->jobctl); LOAD(task->task_works);
2547 * and we can rely on STORE-MB-LOAD [ in task_work_add].
2549 smp_store_mb(current->jobctl, current->jobctl & ~JOBCTL_TASK_WORK);
2550 if (unlikely(current->task_works)) {
2551 spin_unlock_irq(&sighand->siglock);
2557 * Every stopped thread goes here after wakeup. Check to see if
2558 * we should notify the parent, prepare_signal(SIGCONT) encodes
2559 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2561 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2564 if (signal->flags & SIGNAL_CLD_CONTINUED)
2565 why = CLD_CONTINUED;
2569 signal->flags &= ~SIGNAL_CLD_MASK;
2571 spin_unlock_irq(&sighand->siglock);
2574 * Notify the parent that we're continuing. This event is
2575 * always per-process and doesn't make whole lot of sense
2576 * for ptracers, who shouldn't consume the state via
2577 * wait(2) either, but, for backward compatibility, notify
2578 * the ptracer of the group leader too unless it's gonna be
2581 read_lock(&tasklist_lock);
2582 do_notify_parent_cldstop(current, false, why);
2584 if (ptrace_reparented(current->group_leader))
2585 do_notify_parent_cldstop(current->group_leader,
2587 read_unlock(&tasklist_lock);
2592 /* Has this task already been marked for death? */
2593 if (signal_group_exit(signal)) {
2594 ksig->info.si_signo = signr = SIGKILL;
2595 sigdelset(¤t->pending.signal, SIGKILL);
2596 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2597 &sighand->action[SIGKILL - 1]);
2598 recalc_sigpending();
2603 struct k_sigaction *ka;
2605 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2609 if (unlikely(current->jobctl &
2610 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2611 if (current->jobctl & JOBCTL_TRAP_MASK) {
2613 spin_unlock_irq(&sighand->siglock);
2614 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2621 * If the task is leaving the frozen state, let's update
2622 * cgroup counters and reset the frozen bit.
2624 if (unlikely(cgroup_task_frozen(current))) {
2625 spin_unlock_irq(&sighand->siglock);
2626 cgroup_leave_frozen(false);
2631 * Signals generated by the execution of an instruction
2632 * need to be delivered before any other pending signals
2633 * so that the instruction pointer in the signal stack
2634 * frame points to the faulting instruction.
2636 signr = dequeue_synchronous_signal(&ksig->info);
2638 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2641 break; /* will return 0 */
2643 if (unlikely(current->ptrace) && signr != SIGKILL) {
2644 signr = ptrace_signal(signr, &ksig->info);
2649 ka = &sighand->action[signr-1];
2651 /* Trace actually delivered signals. */
2652 trace_signal_deliver(signr, &ksig->info, ka);
2654 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2656 if (ka->sa.sa_handler != SIG_DFL) {
2657 /* Run the handler. */
2660 if (ka->sa.sa_flags & SA_ONESHOT)
2661 ka->sa.sa_handler = SIG_DFL;
2663 break; /* will return non-zero "signr" value */
2667 * Now we are doing the default action for this signal.
2669 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2673 * Global init gets no signals it doesn't want.
2674 * Container-init gets no signals it doesn't want from same
2677 * Note that if global/container-init sees a sig_kernel_only()
2678 * signal here, the signal must have been generated internally
2679 * or must have come from an ancestor namespace. In either
2680 * case, the signal cannot be dropped.
2682 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2683 !sig_kernel_only(signr))
2686 if (sig_kernel_stop(signr)) {
2688 * The default action is to stop all threads in
2689 * the thread group. The job control signals
2690 * do nothing in an orphaned pgrp, but SIGSTOP
2691 * always works. Note that siglock needs to be
2692 * dropped during the call to is_orphaned_pgrp()
2693 * because of lock ordering with tasklist_lock.
2694 * This allows an intervening SIGCONT to be posted.
2695 * We need to check for that and bail out if necessary.
2697 if (signr != SIGSTOP) {
2698 spin_unlock_irq(&sighand->siglock);
2700 /* signals can be posted during this window */
2702 if (is_current_pgrp_orphaned())
2705 spin_lock_irq(&sighand->siglock);
2708 if (likely(do_signal_stop(ksig->info.si_signo))) {
2709 /* It released the siglock. */
2714 * We didn't actually stop, due to a race
2715 * with SIGCONT or something like that.
2721 spin_unlock_irq(&sighand->siglock);
2722 if (unlikely(cgroup_task_frozen(current)))
2723 cgroup_leave_frozen(true);
2726 * Anything else is fatal, maybe with a core dump.
2728 current->flags |= PF_SIGNALED;
2730 if (sig_kernel_coredump(signr)) {
2731 if (print_fatal_signals)
2732 print_fatal_signal(ksig->info.si_signo);
2733 proc_coredump_connector(current);
2735 * If it was able to dump core, this kills all
2736 * other threads in the group and synchronizes with
2737 * their demise. If we lost the race with another
2738 * thread getting here, it set group_exit_code
2739 * first and our do_group_exit call below will use
2740 * that value and ignore the one we pass it.
2742 do_coredump(&ksig->info);
2746 * Death signals, no core dump.
2748 do_group_exit(ksig->info.si_signo);
2751 spin_unlock_irq(&sighand->siglock);
2754 return ksig->sig > 0;
2758 * signal_delivered -
2759 * @ksig: kernel signal struct
2760 * @stepping: nonzero if debugger single-step or block-step in use
2762 * This function should be called when a signal has successfully been
2763 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2764 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2765 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2767 static void signal_delivered(struct ksignal *ksig, int stepping)
2771 /* A signal was successfully delivered, and the
2772 saved sigmask was stored on the signal frame,
2773 and will be restored by sigreturn. So we can
2774 simply clear the restore sigmask flag. */
2775 clear_restore_sigmask();
2777 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2778 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2779 sigaddset(&blocked, ksig->sig);
2780 set_current_blocked(&blocked);
2781 tracehook_signal_handler(stepping);
2784 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2787 force_sigsegv(ksig->sig);
2789 signal_delivered(ksig, stepping);
2793 * It could be that complete_signal() picked us to notify about the
2794 * group-wide signal. Other threads should be notified now to take
2795 * the shared signals in @which since we will not.
2797 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2800 struct task_struct *t;
2802 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2803 if (sigisemptyset(&retarget))
2807 while_each_thread(tsk, t) {
2808 if (t->flags & PF_EXITING)
2811 if (!has_pending_signals(&retarget, &t->blocked))
2813 /* Remove the signals this thread can handle. */
2814 sigandsets(&retarget, &retarget, &t->blocked);
2816 if (!signal_pending(t))
2817 signal_wake_up(t, 0);
2819 if (sigisemptyset(&retarget))
2824 void exit_signals(struct task_struct *tsk)
2830 * @tsk is about to have PF_EXITING set - lock out users which
2831 * expect stable threadgroup.
2833 cgroup_threadgroup_change_begin(tsk);
2835 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2836 tsk->flags |= PF_EXITING;
2837 cgroup_threadgroup_change_end(tsk);
2841 spin_lock_irq(&tsk->sighand->siglock);
2843 * From now this task is not visible for group-wide signals,
2844 * see wants_signal(), do_signal_stop().
2846 tsk->flags |= PF_EXITING;
2848 cgroup_threadgroup_change_end(tsk);
2850 if (!signal_pending(tsk))
2853 unblocked = tsk->blocked;
2854 signotset(&unblocked);
2855 retarget_shared_pending(tsk, &unblocked);
2857 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2858 task_participate_group_stop(tsk))
2859 group_stop = CLD_STOPPED;
2861 spin_unlock_irq(&tsk->sighand->siglock);
2864 * If group stop has completed, deliver the notification. This
2865 * should always go to the real parent of the group leader.
2867 if (unlikely(group_stop)) {
2868 read_lock(&tasklist_lock);
2869 do_notify_parent_cldstop(tsk, false, group_stop);
2870 read_unlock(&tasklist_lock);
2875 * System call entry points.
2879 * sys_restart_syscall - restart a system call
2881 SYSCALL_DEFINE0(restart_syscall)
2883 struct restart_block *restart = ¤t->restart_block;
2884 return restart->fn(restart);
2887 long do_no_restart_syscall(struct restart_block *param)
2892 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2894 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2895 sigset_t newblocked;
2896 /* A set of now blocked but previously unblocked signals. */
2897 sigandnsets(&newblocked, newset, ¤t->blocked);
2898 retarget_shared_pending(tsk, &newblocked);
2900 tsk->blocked = *newset;
2901 recalc_sigpending();
2905 * set_current_blocked - change current->blocked mask
2908 * It is wrong to change ->blocked directly, this helper should be used
2909 * to ensure the process can't miss a shared signal we are going to block.
2911 void set_current_blocked(sigset_t *newset)
2913 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2914 __set_current_blocked(newset);
2917 void __set_current_blocked(const sigset_t *newset)
2919 struct task_struct *tsk = current;
2922 * In case the signal mask hasn't changed, there is nothing we need
2923 * to do. The current->blocked shouldn't be modified by other task.
2925 if (sigequalsets(&tsk->blocked, newset))
2928 spin_lock_irq(&tsk->sighand->siglock);
2929 __set_task_blocked(tsk, newset);
2930 spin_unlock_irq(&tsk->sighand->siglock);
2934 * This is also useful for kernel threads that want to temporarily
2935 * (or permanently) block certain signals.
2937 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2938 * interface happily blocks "unblockable" signals like SIGKILL
2941 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2943 struct task_struct *tsk = current;
2946 /* Lockless, only current can change ->blocked, never from irq */
2948 *oldset = tsk->blocked;
2952 sigorsets(&newset, &tsk->blocked, set);
2955 sigandnsets(&newset, &tsk->blocked, set);
2964 __set_current_blocked(&newset);
2967 EXPORT_SYMBOL(sigprocmask);
2970 * The api helps set app-provided sigmasks.
2972 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2973 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
2975 * Note that it does set_restore_sigmask() in advance, so it must be always
2976 * paired with restore_saved_sigmask_unless() before return from syscall.
2978 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
2984 if (sigsetsize != sizeof(sigset_t))
2986 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
2989 set_restore_sigmask();
2990 current->saved_sigmask = current->blocked;
2991 set_current_blocked(&kmask);
2996 #ifdef CONFIG_COMPAT
2997 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3004 if (sigsetsize != sizeof(compat_sigset_t))
3006 if (get_compat_sigset(&kmask, umask))
3009 set_restore_sigmask();
3010 current->saved_sigmask = current->blocked;
3011 set_current_blocked(&kmask);
3018 * sys_rt_sigprocmask - change the list of currently blocked signals
3019 * @how: whether to add, remove, or set signals
3020 * @nset: stores pending signals
3021 * @oset: previous value of signal mask if non-null
3022 * @sigsetsize: size of sigset_t type
3024 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3025 sigset_t __user *, oset, size_t, sigsetsize)
3027 sigset_t old_set, new_set;
3030 /* XXX: Don't preclude handling different sized sigset_t's. */
3031 if (sigsetsize != sizeof(sigset_t))
3034 old_set = current->blocked;
3037 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3039 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3041 error = sigprocmask(how, &new_set, NULL);
3047 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3054 #ifdef CONFIG_COMPAT
3055 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3056 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3058 sigset_t old_set = current->blocked;
3060 /* XXX: Don't preclude handling different sized sigset_t's. */
3061 if (sigsetsize != sizeof(sigset_t))
3067 if (get_compat_sigset(&new_set, nset))
3069 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3071 error = sigprocmask(how, &new_set, NULL);
3075 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3079 static void do_sigpending(sigset_t *set)
3081 spin_lock_irq(¤t->sighand->siglock);
3082 sigorsets(set, ¤t->pending.signal,
3083 ¤t->signal->shared_pending.signal);
3084 spin_unlock_irq(¤t->sighand->siglock);
3086 /* Outside the lock because only this thread touches it. */
3087 sigandsets(set, ¤t->blocked, set);
3091 * sys_rt_sigpending - examine a pending signal that has been raised
3093 * @uset: stores pending signals
3094 * @sigsetsize: size of sigset_t type or larger
3096 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3100 if (sigsetsize > sizeof(*uset))
3103 do_sigpending(&set);
3105 if (copy_to_user(uset, &set, sigsetsize))
3111 #ifdef CONFIG_COMPAT
3112 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3113 compat_size_t, sigsetsize)
3117 if (sigsetsize > sizeof(*uset))
3120 do_sigpending(&set);
3122 return put_compat_sigset(uset, &set, sigsetsize);
3126 static const struct {
3127 unsigned char limit, layout;
3129 [SIGILL] = { NSIGILL, SIL_FAULT },
3130 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3131 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3132 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3133 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3135 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3137 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3138 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3139 [SIGSYS] = { NSIGSYS, SIL_SYS },
3142 static bool known_siginfo_layout(unsigned sig, int si_code)
3144 if (si_code == SI_KERNEL)
3146 else if ((si_code > SI_USER)) {
3147 if (sig_specific_sicodes(sig)) {
3148 if (si_code <= sig_sicodes[sig].limit)
3151 else if (si_code <= NSIGPOLL)
3154 else if (si_code >= SI_DETHREAD)
3156 else if (si_code == SI_ASYNCNL)
3161 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3163 enum siginfo_layout layout = SIL_KILL;
3164 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3165 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3166 (si_code <= sig_sicodes[sig].limit)) {
3167 layout = sig_sicodes[sig].layout;
3168 /* Handle the exceptions */
3169 if ((sig == SIGBUS) &&
3170 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3171 layout = SIL_FAULT_MCEERR;
3172 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3173 layout = SIL_FAULT_BNDERR;
3175 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3176 layout = SIL_FAULT_PKUERR;
3179 else if (si_code <= NSIGPOLL)
3182 if (si_code == SI_TIMER)
3184 else if (si_code == SI_SIGIO)
3186 else if (si_code < 0)
3192 static inline char __user *si_expansion(const siginfo_t __user *info)
3194 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3197 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3199 char __user *expansion = si_expansion(to);
3200 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3202 if (clear_user(expansion, SI_EXPANSION_SIZE))
3207 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3208 const siginfo_t __user *from)
3210 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3211 char __user *expansion = si_expansion(from);
3212 char buf[SI_EXPANSION_SIZE];
3215 * An unknown si_code might need more than
3216 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3217 * extra bytes are 0. This guarantees copy_siginfo_to_user
3218 * will return this data to userspace exactly.
3220 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3222 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3230 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3231 const siginfo_t __user *from)
3233 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3235 to->si_signo = signo;
3236 return post_copy_siginfo_from_user(to, from);
3239 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3241 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3243 return post_copy_siginfo_from_user(to, from);
3246 #ifdef CONFIG_COMPAT
3248 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3249 * @to: compat siginfo destination
3250 * @from: kernel siginfo source
3252 * Note: This function does not work properly for the SIGCHLD on x32, but
3253 * fortunately it doesn't have to. The only valid callers for this function are
3254 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3255 * The latter does not care because SIGCHLD will never cause a coredump.
3257 void copy_siginfo_to_external32(struct compat_siginfo *to,
3258 const struct kernel_siginfo *from)
3260 memset(to, 0, sizeof(*to));
3262 to->si_signo = from->si_signo;
3263 to->si_errno = from->si_errno;
3264 to->si_code = from->si_code;
3265 switch(siginfo_layout(from->si_signo, from->si_code)) {
3267 to->si_pid = from->si_pid;
3268 to->si_uid = from->si_uid;
3271 to->si_tid = from->si_tid;
3272 to->si_overrun = from->si_overrun;
3273 to->si_int = from->si_int;
3276 to->si_band = from->si_band;
3277 to->si_fd = from->si_fd;
3280 to->si_addr = ptr_to_compat(from->si_addr);
3281 #ifdef __ARCH_SI_TRAPNO
3282 to->si_trapno = from->si_trapno;
3285 case SIL_FAULT_MCEERR:
3286 to->si_addr = ptr_to_compat(from->si_addr);
3287 #ifdef __ARCH_SI_TRAPNO
3288 to->si_trapno = from->si_trapno;
3290 to->si_addr_lsb = from->si_addr_lsb;
3292 case SIL_FAULT_BNDERR:
3293 to->si_addr = ptr_to_compat(from->si_addr);
3294 #ifdef __ARCH_SI_TRAPNO
3295 to->si_trapno = from->si_trapno;
3297 to->si_lower = ptr_to_compat(from->si_lower);
3298 to->si_upper = ptr_to_compat(from->si_upper);
3300 case SIL_FAULT_PKUERR:
3301 to->si_addr = ptr_to_compat(from->si_addr);
3302 #ifdef __ARCH_SI_TRAPNO
3303 to->si_trapno = from->si_trapno;
3305 to->si_pkey = from->si_pkey;
3308 to->si_pid = from->si_pid;
3309 to->si_uid = from->si_uid;
3310 to->si_status = from->si_status;
3311 to->si_utime = from->si_utime;
3312 to->si_stime = from->si_stime;
3315 to->si_pid = from->si_pid;
3316 to->si_uid = from->si_uid;
3317 to->si_int = from->si_int;
3320 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3321 to->si_syscall = from->si_syscall;
3322 to->si_arch = from->si_arch;
3327 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3328 const struct kernel_siginfo *from)
3330 struct compat_siginfo new;
3332 copy_siginfo_to_external32(&new, from);
3333 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3338 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3339 const struct compat_siginfo *from)
3342 to->si_signo = from->si_signo;
3343 to->si_errno = from->si_errno;
3344 to->si_code = from->si_code;
3345 switch(siginfo_layout(from->si_signo, from->si_code)) {
3347 to->si_pid = from->si_pid;
3348 to->si_uid = from->si_uid;
3351 to->si_tid = from->si_tid;
3352 to->si_overrun = from->si_overrun;
3353 to->si_int = from->si_int;
3356 to->si_band = from->si_band;
3357 to->si_fd = from->si_fd;
3360 to->si_addr = compat_ptr(from->si_addr);
3361 #ifdef __ARCH_SI_TRAPNO
3362 to->si_trapno = from->si_trapno;
3365 case SIL_FAULT_MCEERR:
3366 to->si_addr = compat_ptr(from->si_addr);
3367 #ifdef __ARCH_SI_TRAPNO
3368 to->si_trapno = from->si_trapno;
3370 to->si_addr_lsb = from->si_addr_lsb;
3372 case SIL_FAULT_BNDERR:
3373 to->si_addr = compat_ptr(from->si_addr);
3374 #ifdef __ARCH_SI_TRAPNO
3375 to->si_trapno = from->si_trapno;
3377 to->si_lower = compat_ptr(from->si_lower);
3378 to->si_upper = compat_ptr(from->si_upper);
3380 case SIL_FAULT_PKUERR:
3381 to->si_addr = compat_ptr(from->si_addr);
3382 #ifdef __ARCH_SI_TRAPNO
3383 to->si_trapno = from->si_trapno;
3385 to->si_pkey = from->si_pkey;
3388 to->si_pid = from->si_pid;
3389 to->si_uid = from->si_uid;
3390 to->si_status = from->si_status;
3391 #ifdef CONFIG_X86_X32_ABI
3392 if (in_x32_syscall()) {
3393 to->si_utime = from->_sifields._sigchld_x32._utime;
3394 to->si_stime = from->_sifields._sigchld_x32._stime;
3398 to->si_utime = from->si_utime;
3399 to->si_stime = from->si_stime;
3403 to->si_pid = from->si_pid;
3404 to->si_uid = from->si_uid;
3405 to->si_int = from->si_int;
3408 to->si_call_addr = compat_ptr(from->si_call_addr);
3409 to->si_syscall = from->si_syscall;
3410 to->si_arch = from->si_arch;
3416 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3417 const struct compat_siginfo __user *ufrom)
3419 struct compat_siginfo from;
3421 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3424 from.si_signo = signo;
3425 return post_copy_siginfo_from_user32(to, &from);
3428 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3429 const struct compat_siginfo __user *ufrom)
3431 struct compat_siginfo from;
3433 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3436 return post_copy_siginfo_from_user32(to, &from);
3438 #endif /* CONFIG_COMPAT */
3441 * do_sigtimedwait - wait for queued signals specified in @which
3442 * @which: queued signals to wait for
3443 * @info: if non-null, the signal's siginfo is returned here
3444 * @ts: upper bound on process time suspension
3446 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3447 const struct timespec64 *ts)
3449 ktime_t *to = NULL, timeout = KTIME_MAX;
3450 struct task_struct *tsk = current;
3451 sigset_t mask = *which;
3455 if (!timespec64_valid(ts))
3457 timeout = timespec64_to_ktime(*ts);
3462 * Invert the set of allowed signals to get those we want to block.
3464 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3467 spin_lock_irq(&tsk->sighand->siglock);
3468 sig = dequeue_signal(tsk, &mask, info);
3469 if (!sig && timeout) {
3471 * None ready, temporarily unblock those we're interested
3472 * while we are sleeping in so that we'll be awakened when
3473 * they arrive. Unblocking is always fine, we can avoid
3474 * set_current_blocked().
3476 tsk->real_blocked = tsk->blocked;
3477 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3478 recalc_sigpending();
3479 spin_unlock_irq(&tsk->sighand->siglock);
3481 __set_current_state(TASK_INTERRUPTIBLE);
3482 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3484 spin_lock_irq(&tsk->sighand->siglock);
3485 __set_task_blocked(tsk, &tsk->real_blocked);
3486 sigemptyset(&tsk->real_blocked);
3487 sig = dequeue_signal(tsk, &mask, info);
3489 spin_unlock_irq(&tsk->sighand->siglock);
3493 return ret ? -EINTR : -EAGAIN;
3497 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3499 * @uthese: queued signals to wait for
3500 * @uinfo: if non-null, the signal's siginfo is returned here
3501 * @uts: upper bound on process time suspension
3502 * @sigsetsize: size of sigset_t type
3504 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3505 siginfo_t __user *, uinfo,
3506 const struct __kernel_timespec __user *, uts,
3510 struct timespec64 ts;
3511 kernel_siginfo_t info;
3514 /* XXX: Don't preclude handling different sized sigset_t's. */
3515 if (sigsetsize != sizeof(sigset_t))
3518 if (copy_from_user(&these, uthese, sizeof(these)))
3522 if (get_timespec64(&ts, uts))
3526 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3528 if (ret > 0 && uinfo) {
3529 if (copy_siginfo_to_user(uinfo, &info))
3536 #ifdef CONFIG_COMPAT_32BIT_TIME
3537 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3538 siginfo_t __user *, uinfo,
3539 const struct old_timespec32 __user *, uts,
3543 struct timespec64 ts;
3544 kernel_siginfo_t info;
3547 if (sigsetsize != sizeof(sigset_t))
3550 if (copy_from_user(&these, uthese, sizeof(these)))
3554 if (get_old_timespec32(&ts, uts))
3558 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3560 if (ret > 0 && uinfo) {
3561 if (copy_siginfo_to_user(uinfo, &info))
3569 #ifdef CONFIG_COMPAT
3570 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3571 struct compat_siginfo __user *, uinfo,
3572 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3575 struct timespec64 t;
3576 kernel_siginfo_t info;
3579 if (sigsetsize != sizeof(sigset_t))
3582 if (get_compat_sigset(&s, uthese))
3586 if (get_timespec64(&t, uts))
3590 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3592 if (ret > 0 && uinfo) {
3593 if (copy_siginfo_to_user32(uinfo, &info))
3600 #ifdef CONFIG_COMPAT_32BIT_TIME
3601 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3602 struct compat_siginfo __user *, uinfo,
3603 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3606 struct timespec64 t;
3607 kernel_siginfo_t info;
3610 if (sigsetsize != sizeof(sigset_t))
3613 if (get_compat_sigset(&s, uthese))
3617 if (get_old_timespec32(&t, uts))
3621 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3623 if (ret > 0 && uinfo) {
3624 if (copy_siginfo_to_user32(uinfo, &info))
3633 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3635 clear_siginfo(info);
3636 info->si_signo = sig;
3638 info->si_code = SI_USER;
3639 info->si_pid = task_tgid_vnr(current);
3640 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3644 * sys_kill - send a signal to a process
3645 * @pid: the PID of the process
3646 * @sig: signal to be sent
3648 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3650 struct kernel_siginfo info;
3652 prepare_kill_siginfo(sig, &info);
3654 return kill_something_info(sig, &info, pid);
3658 * Verify that the signaler and signalee either are in the same pid namespace
3659 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3662 static bool access_pidfd_pidns(struct pid *pid)
3664 struct pid_namespace *active = task_active_pid_ns(current);
3665 struct pid_namespace *p = ns_of_pid(pid);
3678 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, siginfo_t *info)
3680 #ifdef CONFIG_COMPAT
3682 * Avoid hooking up compat syscalls and instead handle necessary
3683 * conversions here. Note, this is a stop-gap measure and should not be
3684 * considered a generic solution.
3686 if (in_compat_syscall())
3687 return copy_siginfo_from_user32(
3688 kinfo, (struct compat_siginfo __user *)info);
3690 return copy_siginfo_from_user(kinfo, info);
3693 static struct pid *pidfd_to_pid(const struct file *file)
3697 pid = pidfd_pid(file);
3701 return tgid_pidfd_to_pid(file);
3705 * sys_pidfd_send_signal - Signal a process through a pidfd
3706 * @pidfd: file descriptor of the process
3707 * @sig: signal to send
3708 * @info: signal info
3709 * @flags: future flags
3711 * The syscall currently only signals via PIDTYPE_PID which covers
3712 * kill(<positive-pid>, <signal>. It does not signal threads or process
3714 * In order to extend the syscall to threads and process groups the @flags
3715 * argument should be used. In essence, the @flags argument will determine
3716 * what is signaled and not the file descriptor itself. Put in other words,
3717 * grouping is a property of the flags argument not a property of the file
3720 * Return: 0 on success, negative errno on failure
3722 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3723 siginfo_t __user *, info, unsigned int, flags)
3728 kernel_siginfo_t kinfo;
3730 /* Enforce flags be set to 0 until we add an extension. */
3738 /* Is this a pidfd? */
3739 pid = pidfd_to_pid(f.file);
3746 if (!access_pidfd_pidns(pid))
3750 ret = copy_siginfo_from_user_any(&kinfo, info);
3755 if (unlikely(sig != kinfo.si_signo))
3758 /* Only allow sending arbitrary signals to yourself. */
3760 if ((task_pid(current) != pid) &&
3761 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3764 prepare_kill_siginfo(sig, &kinfo);
3767 ret = kill_pid_info(sig, &kinfo, pid);
3775 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3777 struct task_struct *p;
3781 p = find_task_by_vpid(pid);
3782 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3783 error = check_kill_permission(sig, info, p);
3785 * The null signal is a permissions and process existence
3786 * probe. No signal is actually delivered.
3788 if (!error && sig) {
3789 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3791 * If lock_task_sighand() failed we pretend the task
3792 * dies after receiving the signal. The window is tiny,
3793 * and the signal is private anyway.
3795 if (unlikely(error == -ESRCH))
3804 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3806 struct kernel_siginfo info;
3808 clear_siginfo(&info);
3809 info.si_signo = sig;
3811 info.si_code = SI_TKILL;
3812 info.si_pid = task_tgid_vnr(current);
3813 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3815 return do_send_specific(tgid, pid, sig, &info);
3819 * sys_tgkill - send signal to one specific thread
3820 * @tgid: the thread group ID of the thread
3821 * @pid: the PID of the thread
3822 * @sig: signal to be sent
3824 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3825 * exists but it's not belonging to the target process anymore. This
3826 * method solves the problem of threads exiting and PIDs getting reused.
3828 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3830 /* This is only valid for single tasks */
3831 if (pid <= 0 || tgid <= 0)
3834 return do_tkill(tgid, pid, sig);
3838 * sys_tkill - send signal to one specific task
3839 * @pid: the PID of the task
3840 * @sig: signal to be sent
3842 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3844 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3846 /* This is only valid for single tasks */
3850 return do_tkill(0, pid, sig);
3853 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3855 /* Not even root can pretend to send signals from the kernel.
3856 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3858 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3859 (task_pid_vnr(current) != pid))
3862 /* POSIX.1b doesn't mention process groups. */
3863 return kill_proc_info(sig, info, pid);
3867 * sys_rt_sigqueueinfo - send signal information to a signal
3868 * @pid: the PID of the thread
3869 * @sig: signal to be sent
3870 * @uinfo: signal info to be sent
3872 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3873 siginfo_t __user *, uinfo)
3875 kernel_siginfo_t info;
3876 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3879 return do_rt_sigqueueinfo(pid, sig, &info);
3882 #ifdef CONFIG_COMPAT
3883 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3886 struct compat_siginfo __user *, uinfo)
3888 kernel_siginfo_t info;
3889 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3892 return do_rt_sigqueueinfo(pid, sig, &info);
3896 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
3898 /* This is only valid for single tasks */
3899 if (pid <= 0 || tgid <= 0)
3902 /* Not even root can pretend to send signals from the kernel.
3903 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3905 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3906 (task_pid_vnr(current) != pid))
3909 return do_send_specific(tgid, pid, sig, info);
3912 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3913 siginfo_t __user *, uinfo)
3915 kernel_siginfo_t info;
3916 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3919 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3922 #ifdef CONFIG_COMPAT
3923 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3927 struct compat_siginfo __user *, uinfo)
3929 kernel_siginfo_t info;
3930 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3933 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3938 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3940 void kernel_sigaction(int sig, __sighandler_t action)
3942 spin_lock_irq(¤t->sighand->siglock);
3943 current->sighand->action[sig - 1].sa.sa_handler = action;
3944 if (action == SIG_IGN) {
3948 sigaddset(&mask, sig);
3950 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3951 flush_sigqueue_mask(&mask, ¤t->pending);
3952 recalc_sigpending();
3954 spin_unlock_irq(¤t->sighand->siglock);
3956 EXPORT_SYMBOL(kernel_sigaction);
3958 void __weak sigaction_compat_abi(struct k_sigaction *act,
3959 struct k_sigaction *oact)
3963 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3965 struct task_struct *p = current, *t;
3966 struct k_sigaction *k;
3969 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3972 k = &p->sighand->action[sig-1];
3974 spin_lock_irq(&p->sighand->siglock);
3978 sigaction_compat_abi(act, oact);
3981 sigdelsetmask(&act->sa.sa_mask,
3982 sigmask(SIGKILL) | sigmask(SIGSTOP));
3986 * "Setting a signal action to SIG_IGN for a signal that is
3987 * pending shall cause the pending signal to be discarded,
3988 * whether or not it is blocked."
3990 * "Setting a signal action to SIG_DFL for a signal that is
3991 * pending and whose default action is to ignore the signal
3992 * (for example, SIGCHLD), shall cause the pending signal to
3993 * be discarded, whether or not it is blocked"
3995 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3997 sigaddset(&mask, sig);
3998 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3999 for_each_thread(p, t)
4000 flush_sigqueue_mask(&mask, &t->pending);
4004 spin_unlock_irq(&p->sighand->siglock);
4009 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4012 struct task_struct *t = current;
4015 memset(oss, 0, sizeof(stack_t));
4016 oss->ss_sp = (void __user *) t->sas_ss_sp;
4017 oss->ss_size = t->sas_ss_size;
4018 oss->ss_flags = sas_ss_flags(sp) |
4019 (current->sas_ss_flags & SS_FLAG_BITS);
4023 void __user *ss_sp = ss->ss_sp;
4024 size_t ss_size = ss->ss_size;
4025 unsigned ss_flags = ss->ss_flags;
4028 if (unlikely(on_sig_stack(sp)))
4031 ss_mode = ss_flags & ~SS_FLAG_BITS;
4032 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4036 if (ss_mode == SS_DISABLE) {
4040 if (unlikely(ss_size < min_ss_size))
4044 t->sas_ss_sp = (unsigned long) ss_sp;
4045 t->sas_ss_size = ss_size;
4046 t->sas_ss_flags = ss_flags;
4051 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4055 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4057 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4058 current_user_stack_pointer(),
4060 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4065 int restore_altstack(const stack_t __user *uss)
4068 if (copy_from_user(&new, uss, sizeof(stack_t)))
4070 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4072 /* squash all but EFAULT for now */
4076 int __save_altstack(stack_t __user *uss, unsigned long sp)
4078 struct task_struct *t = current;
4079 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4080 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4081 __put_user(t->sas_ss_size, &uss->ss_size);
4084 if (t->sas_ss_flags & SS_AUTODISARM)
4089 #ifdef CONFIG_COMPAT
4090 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4091 compat_stack_t __user *uoss_ptr)
4097 compat_stack_t uss32;
4098 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4100 uss.ss_sp = compat_ptr(uss32.ss_sp);
4101 uss.ss_flags = uss32.ss_flags;
4102 uss.ss_size = uss32.ss_size;
4104 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4105 compat_user_stack_pointer(),
4106 COMPAT_MINSIGSTKSZ);
4107 if (ret >= 0 && uoss_ptr) {
4109 memset(&old, 0, sizeof(old));
4110 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4111 old.ss_flags = uoss.ss_flags;
4112 old.ss_size = uoss.ss_size;
4113 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4119 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4120 const compat_stack_t __user *, uss_ptr,
4121 compat_stack_t __user *, uoss_ptr)
4123 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4126 int compat_restore_altstack(const compat_stack_t __user *uss)
4128 int err = do_compat_sigaltstack(uss, NULL);
4129 /* squash all but -EFAULT for now */
4130 return err == -EFAULT ? err : 0;
4133 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4136 struct task_struct *t = current;
4137 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4139 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4140 __put_user(t->sas_ss_size, &uss->ss_size);
4143 if (t->sas_ss_flags & SS_AUTODISARM)
4149 #ifdef __ARCH_WANT_SYS_SIGPENDING
4152 * sys_sigpending - examine pending signals
4153 * @uset: where mask of pending signal is returned
4155 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4159 if (sizeof(old_sigset_t) > sizeof(*uset))
4162 do_sigpending(&set);
4164 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4170 #ifdef CONFIG_COMPAT
4171 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4175 do_sigpending(&set);
4177 return put_user(set.sig[0], set32);
4183 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4185 * sys_sigprocmask - examine and change blocked signals
4186 * @how: whether to add, remove, or set signals
4187 * @nset: signals to add or remove (if non-null)
4188 * @oset: previous value of signal mask if non-null
4190 * Some platforms have their own version with special arguments;
4191 * others support only sys_rt_sigprocmask.
4194 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4195 old_sigset_t __user *, oset)
4197 old_sigset_t old_set, new_set;
4198 sigset_t new_blocked;
4200 old_set = current->blocked.sig[0];
4203 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4206 new_blocked = current->blocked;
4210 sigaddsetmask(&new_blocked, new_set);
4213 sigdelsetmask(&new_blocked, new_set);
4216 new_blocked.sig[0] = new_set;
4222 set_current_blocked(&new_blocked);
4226 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4232 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4234 #ifndef CONFIG_ODD_RT_SIGACTION
4236 * sys_rt_sigaction - alter an action taken by a process
4237 * @sig: signal to be sent
4238 * @act: new sigaction
4239 * @oact: used to save the previous sigaction
4240 * @sigsetsize: size of sigset_t type
4242 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4243 const struct sigaction __user *, act,
4244 struct sigaction __user *, oact,
4247 struct k_sigaction new_sa, old_sa;
4250 /* XXX: Don't preclude handling different sized sigset_t's. */
4251 if (sigsetsize != sizeof(sigset_t))
4254 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4257 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4261 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4266 #ifdef CONFIG_COMPAT
4267 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4268 const struct compat_sigaction __user *, act,
4269 struct compat_sigaction __user *, oact,
4270 compat_size_t, sigsetsize)
4272 struct k_sigaction new_ka, old_ka;
4273 #ifdef __ARCH_HAS_SA_RESTORER
4274 compat_uptr_t restorer;
4278 /* XXX: Don't preclude handling different sized sigset_t's. */
4279 if (sigsetsize != sizeof(compat_sigset_t))
4283 compat_uptr_t handler;
4284 ret = get_user(handler, &act->sa_handler);
4285 new_ka.sa.sa_handler = compat_ptr(handler);
4286 #ifdef __ARCH_HAS_SA_RESTORER
4287 ret |= get_user(restorer, &act->sa_restorer);
4288 new_ka.sa.sa_restorer = compat_ptr(restorer);
4290 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4291 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4296 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4298 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4300 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4301 sizeof(oact->sa_mask));
4302 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4303 #ifdef __ARCH_HAS_SA_RESTORER
4304 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4305 &oact->sa_restorer);
4311 #endif /* !CONFIG_ODD_RT_SIGACTION */
4313 #ifdef CONFIG_OLD_SIGACTION
4314 SYSCALL_DEFINE3(sigaction, int, sig,
4315 const struct old_sigaction __user *, act,
4316 struct old_sigaction __user *, oact)
4318 struct k_sigaction new_ka, old_ka;
4323 if (!access_ok(act, sizeof(*act)) ||
4324 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4325 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4326 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4327 __get_user(mask, &act->sa_mask))
4329 #ifdef __ARCH_HAS_KA_RESTORER
4330 new_ka.ka_restorer = NULL;
4332 siginitset(&new_ka.sa.sa_mask, mask);
4335 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4338 if (!access_ok(oact, sizeof(*oact)) ||
4339 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4340 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4341 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4342 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4349 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4350 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4351 const struct compat_old_sigaction __user *, act,
4352 struct compat_old_sigaction __user *, oact)
4354 struct k_sigaction new_ka, old_ka;
4356 compat_old_sigset_t mask;
4357 compat_uptr_t handler, restorer;
4360 if (!access_ok(act, sizeof(*act)) ||
4361 __get_user(handler, &act->sa_handler) ||
4362 __get_user(restorer, &act->sa_restorer) ||
4363 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4364 __get_user(mask, &act->sa_mask))
4367 #ifdef __ARCH_HAS_KA_RESTORER
4368 new_ka.ka_restorer = NULL;
4370 new_ka.sa.sa_handler = compat_ptr(handler);
4371 new_ka.sa.sa_restorer = compat_ptr(restorer);
4372 siginitset(&new_ka.sa.sa_mask, mask);
4375 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4378 if (!access_ok(oact, sizeof(*oact)) ||
4379 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4380 &oact->sa_handler) ||
4381 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4382 &oact->sa_restorer) ||
4383 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4384 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4391 #ifdef CONFIG_SGETMASK_SYSCALL
4394 * For backwards compatibility. Functionality superseded by sigprocmask.
4396 SYSCALL_DEFINE0(sgetmask)
4399 return current->blocked.sig[0];
4402 SYSCALL_DEFINE1(ssetmask, int, newmask)
4404 int old = current->blocked.sig[0];
4407 siginitset(&newset, newmask);
4408 set_current_blocked(&newset);
4412 #endif /* CONFIG_SGETMASK_SYSCALL */
4414 #ifdef __ARCH_WANT_SYS_SIGNAL
4416 * For backwards compatibility. Functionality superseded by sigaction.
4418 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4420 struct k_sigaction new_sa, old_sa;
4423 new_sa.sa.sa_handler = handler;
4424 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4425 sigemptyset(&new_sa.sa.sa_mask);
4427 ret = do_sigaction(sig, &new_sa, &old_sa);
4429 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4431 #endif /* __ARCH_WANT_SYS_SIGNAL */
4433 #ifdef __ARCH_WANT_SYS_PAUSE
4435 SYSCALL_DEFINE0(pause)
4437 while (!signal_pending(current)) {
4438 __set_current_state(TASK_INTERRUPTIBLE);
4441 return -ERESTARTNOHAND;
4446 static int sigsuspend(sigset_t *set)
4448 current->saved_sigmask = current->blocked;
4449 set_current_blocked(set);
4451 while (!signal_pending(current)) {
4452 __set_current_state(TASK_INTERRUPTIBLE);
4455 set_restore_sigmask();
4456 return -ERESTARTNOHAND;
4460 * sys_rt_sigsuspend - replace the signal mask for a value with the
4461 * @unewset value until a signal is received
4462 * @unewset: new signal mask value
4463 * @sigsetsize: size of sigset_t type
4465 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4469 /* XXX: Don't preclude handling different sized sigset_t's. */
4470 if (sigsetsize != sizeof(sigset_t))
4473 if (copy_from_user(&newset, unewset, sizeof(newset)))
4475 return sigsuspend(&newset);
4478 #ifdef CONFIG_COMPAT
4479 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4483 /* XXX: Don't preclude handling different sized sigset_t's. */
4484 if (sigsetsize != sizeof(sigset_t))
4487 if (get_compat_sigset(&newset, unewset))
4489 return sigsuspend(&newset);
4493 #ifdef CONFIG_OLD_SIGSUSPEND
4494 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4497 siginitset(&blocked, mask);
4498 return sigsuspend(&blocked);
4501 #ifdef CONFIG_OLD_SIGSUSPEND3
4502 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4505 siginitset(&blocked, mask);
4506 return sigsuspend(&blocked);
4510 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4515 static inline void siginfo_buildtime_checks(void)
4517 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4519 /* Verify the offsets in the two siginfos match */
4520 #define CHECK_OFFSET(field) \
4521 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4524 CHECK_OFFSET(si_pid);
4525 CHECK_OFFSET(si_uid);
4528 CHECK_OFFSET(si_tid);
4529 CHECK_OFFSET(si_overrun);
4530 CHECK_OFFSET(si_value);
4533 CHECK_OFFSET(si_pid);
4534 CHECK_OFFSET(si_uid);
4535 CHECK_OFFSET(si_value);
4538 CHECK_OFFSET(si_pid);
4539 CHECK_OFFSET(si_uid);
4540 CHECK_OFFSET(si_status);
4541 CHECK_OFFSET(si_utime);
4542 CHECK_OFFSET(si_stime);
4545 CHECK_OFFSET(si_addr);
4546 CHECK_OFFSET(si_addr_lsb);
4547 CHECK_OFFSET(si_lower);
4548 CHECK_OFFSET(si_upper);
4549 CHECK_OFFSET(si_pkey);
4552 CHECK_OFFSET(si_band);
4553 CHECK_OFFSET(si_fd);
4556 CHECK_OFFSET(si_call_addr);
4557 CHECK_OFFSET(si_syscall);
4558 CHECK_OFFSET(si_arch);
4562 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4563 offsetof(struct siginfo, si_addr));
4564 if (sizeof(int) == sizeof(void __user *)) {
4565 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4566 sizeof(void __user *));
4568 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4569 sizeof_field(struct siginfo, si_uid)) !=
4570 sizeof(void __user *));
4571 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4572 offsetof(struct siginfo, si_uid));
4574 #ifdef CONFIG_COMPAT
4575 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4576 offsetof(struct compat_siginfo, si_addr));
4577 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4578 sizeof(compat_uptr_t));
4579 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4580 sizeof_field(struct siginfo, si_pid));
4584 void __init signals_init(void)
4586 siginfo_buildtime_checks();
4588 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
4591 #ifdef CONFIG_KGDB_KDB
4592 #include <linux/kdb.h>
4594 * kdb_send_sig - Allows kdb to send signals without exposing
4595 * signal internals. This function checks if the required locks are
4596 * available before calling the main signal code, to avoid kdb
4599 void kdb_send_sig(struct task_struct *t, int sig)
4601 static struct task_struct *kdb_prev_t;
4603 if (!spin_trylock(&t->sighand->siglock)) {
4604 kdb_printf("Can't do kill command now.\n"
4605 "The sigmask lock is held somewhere else in "
4606 "kernel, try again later\n");
4609 new_t = kdb_prev_t != t;
4611 if (t->state != TASK_RUNNING && new_t) {
4612 spin_unlock(&t->sighand->siglock);
4613 kdb_printf("Process is not RUNNING, sending a signal from "
4614 "kdb risks deadlock\n"
4615 "on the run queue locks. "
4616 "The signal has _not_ been sent.\n"
4617 "Reissue the kill command if you want to risk "
4621 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4622 spin_unlock(&t->sighand->siglock);
4624 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4627 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4629 #endif /* CONFIG_KGDB_KDB */