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>
49 #define CREATE_TRACE_POINTS
50 #include <trace/events/signal.h>
52 #include <asm/param.h>
53 #include <linux/uaccess.h>
54 #include <asm/unistd.h>
55 #include <asm/siginfo.h>
56 #include <asm/cacheflush.h>
57 #include "audit.h" /* audit_signal_info() */
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 return sig_handler_ignored(handler, sig);
96 static bool sig_ignored(struct task_struct *t, int sig, bool force)
99 * Blocked signals are never ignored, since the
100 * signal handler may change by the time it is
103 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
107 * Tracers may want to know about even ignored signal unless it
108 * is SIGKILL which can't be reported anyway but can be ignored
109 * by SIGNAL_UNKILLABLE task.
111 if (t->ptrace && sig != SIGKILL)
114 return sig_task_ignored(t, sig, force);
118 * Re-calculate pending state from the set of locally pending
119 * signals, globally pending signals, and blocked signals.
121 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
126 switch (_NSIG_WORDS) {
128 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
129 ready |= signal->sig[i] &~ blocked->sig[i];
132 case 4: ready = signal->sig[3] &~ blocked->sig[3];
133 ready |= signal->sig[2] &~ blocked->sig[2];
134 ready |= signal->sig[1] &~ blocked->sig[1];
135 ready |= signal->sig[0] &~ blocked->sig[0];
138 case 2: ready = signal->sig[1] &~ blocked->sig[1];
139 ready |= signal->sig[0] &~ blocked->sig[0];
142 case 1: ready = signal->sig[0] &~ blocked->sig[0];
147 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
149 static bool recalc_sigpending_tsk(struct task_struct *t)
151 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
152 PENDING(&t->pending, &t->blocked) ||
153 PENDING(&t->signal->shared_pending, &t->blocked) ||
154 cgroup_task_frozen(t)) {
155 set_tsk_thread_flag(t, TIF_SIGPENDING);
160 * We must never clear the flag in another thread, or in current
161 * when it's possible the current syscall is returning -ERESTART*.
162 * So we don't clear it here, and only callers who know they should do.
168 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
169 * This is superfluous when called on current, the wakeup is a harmless no-op.
171 void recalc_sigpending_and_wake(struct task_struct *t)
173 if (recalc_sigpending_tsk(t))
174 signal_wake_up(t, 0);
177 void recalc_sigpending(void)
179 if (!recalc_sigpending_tsk(current) && !freezing(current) &&
180 !klp_patch_pending(current))
181 clear_thread_flag(TIF_SIGPENDING);
184 EXPORT_SYMBOL(recalc_sigpending);
186 void calculate_sigpending(void)
188 /* Have any signals or users of TIF_SIGPENDING been delayed
191 spin_lock_irq(¤t->sighand->siglock);
192 set_tsk_thread_flag(current, TIF_SIGPENDING);
194 spin_unlock_irq(¤t->sighand->siglock);
197 /* Given the mask, find the first available signal that should be serviced. */
199 #define SYNCHRONOUS_MASK \
200 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
201 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
203 int next_signal(struct sigpending *pending, sigset_t *mask)
205 unsigned long i, *s, *m, x;
208 s = pending->signal.sig;
212 * Handle the first word specially: it contains the
213 * synchronous signals that need to be dequeued first.
217 if (x & SYNCHRONOUS_MASK)
218 x &= SYNCHRONOUS_MASK;
223 switch (_NSIG_WORDS) {
225 for (i = 1; i < _NSIG_WORDS; ++i) {
229 sig = ffz(~x) + i*_NSIG_BPW + 1;
238 sig = ffz(~x) + _NSIG_BPW + 1;
249 static inline void print_dropped_signal(int sig)
251 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
253 if (!print_fatal_signals)
256 if (!__ratelimit(&ratelimit_state))
259 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
260 current->comm, current->pid, sig);
264 * task_set_jobctl_pending - set jobctl pending bits
266 * @mask: pending bits to set
268 * Clear @mask from @task->jobctl. @mask must be subset of
269 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
270 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
271 * cleared. If @task is already being killed or exiting, this function
275 * Must be called with @task->sighand->siglock held.
278 * %true if @mask is set, %false if made noop because @task was dying.
280 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
282 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
283 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
284 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
286 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
289 if (mask & JOBCTL_STOP_SIGMASK)
290 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
292 task->jobctl |= mask;
297 * task_clear_jobctl_trapping - clear jobctl trapping bit
300 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
301 * Clear it and wake up the ptracer. Note that we don't need any further
302 * locking. @task->siglock guarantees that @task->parent points to the
306 * Must be called with @task->sighand->siglock held.
308 void task_clear_jobctl_trapping(struct task_struct *task)
310 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
311 task->jobctl &= ~JOBCTL_TRAPPING;
312 smp_mb(); /* advised by wake_up_bit() */
313 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
318 * task_clear_jobctl_pending - clear jobctl pending bits
320 * @mask: pending bits to clear
322 * Clear @mask from @task->jobctl. @mask must be subset of
323 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
324 * STOP bits are cleared together.
326 * If clearing of @mask leaves no stop or trap pending, this function calls
327 * task_clear_jobctl_trapping().
330 * Must be called with @task->sighand->siglock held.
332 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
334 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
336 if (mask & JOBCTL_STOP_PENDING)
337 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
339 task->jobctl &= ~mask;
341 if (!(task->jobctl & JOBCTL_PENDING_MASK))
342 task_clear_jobctl_trapping(task);
346 * task_participate_group_stop - participate in a group stop
347 * @task: task participating in a group stop
349 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
350 * Group stop states are cleared and the group stop count is consumed if
351 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
352 * stop, the appropriate %SIGNAL_* flags are set.
355 * Must be called with @task->sighand->siglock held.
358 * %true if group stop completion should be notified to the parent, %false
361 static bool task_participate_group_stop(struct task_struct *task)
363 struct signal_struct *sig = task->signal;
364 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
366 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
368 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
373 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
374 sig->group_stop_count--;
377 * Tell the caller to notify completion iff we are entering into a
378 * fresh group stop. Read comment in do_signal_stop() for details.
380 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
381 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
387 void task_join_group_stop(struct task_struct *task)
389 /* Have the new thread join an on-going signal group stop */
390 unsigned long jobctl = current->jobctl;
391 if (jobctl & JOBCTL_STOP_PENDING) {
392 struct signal_struct *sig = current->signal;
393 unsigned long signr = jobctl & JOBCTL_STOP_SIGMASK;
394 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
395 if (task_set_jobctl_pending(task, signr | gstop)) {
396 sig->group_stop_count++;
402 * allocate a new signal queue record
403 * - this may be called without locks if and only if t == current, otherwise an
404 * appropriate lock must be held to stop the target task from exiting
406 static struct sigqueue *
407 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
409 struct sigqueue *q = NULL;
410 struct user_struct *user;
413 * Protect access to @t credentials. This can go away when all
414 * callers hold rcu read lock.
417 user = get_uid(__task_cred(t)->user);
418 atomic_inc(&user->sigpending);
421 if (override_rlimit ||
422 atomic_read(&user->sigpending) <=
423 task_rlimit(t, RLIMIT_SIGPENDING)) {
424 q = kmem_cache_alloc(sigqueue_cachep, flags);
426 print_dropped_signal(sig);
429 if (unlikely(q == NULL)) {
430 atomic_dec(&user->sigpending);
433 INIT_LIST_HEAD(&q->list);
441 static void __sigqueue_free(struct sigqueue *q)
443 if (q->flags & SIGQUEUE_PREALLOC)
445 atomic_dec(&q->user->sigpending);
447 kmem_cache_free(sigqueue_cachep, q);
450 void flush_sigqueue(struct sigpending *queue)
454 sigemptyset(&queue->signal);
455 while (!list_empty(&queue->list)) {
456 q = list_entry(queue->list.next, struct sigqueue , list);
457 list_del_init(&q->list);
463 * Flush all pending signals for this kthread.
465 void flush_signals(struct task_struct *t)
469 spin_lock_irqsave(&t->sighand->siglock, flags);
470 clear_tsk_thread_flag(t, TIF_SIGPENDING);
471 flush_sigqueue(&t->pending);
472 flush_sigqueue(&t->signal->shared_pending);
473 spin_unlock_irqrestore(&t->sighand->siglock, flags);
475 EXPORT_SYMBOL(flush_signals);
477 #ifdef CONFIG_POSIX_TIMERS
478 static void __flush_itimer_signals(struct sigpending *pending)
480 sigset_t signal, retain;
481 struct sigqueue *q, *n;
483 signal = pending->signal;
484 sigemptyset(&retain);
486 list_for_each_entry_safe(q, n, &pending->list, list) {
487 int sig = q->info.si_signo;
489 if (likely(q->info.si_code != SI_TIMER)) {
490 sigaddset(&retain, sig);
492 sigdelset(&signal, sig);
493 list_del_init(&q->list);
498 sigorsets(&pending->signal, &signal, &retain);
501 void flush_itimer_signals(void)
503 struct task_struct *tsk = current;
506 spin_lock_irqsave(&tsk->sighand->siglock, flags);
507 __flush_itimer_signals(&tsk->pending);
508 __flush_itimer_signals(&tsk->signal->shared_pending);
509 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
513 void ignore_signals(struct task_struct *t)
517 for (i = 0; i < _NSIG; ++i)
518 t->sighand->action[i].sa.sa_handler = SIG_IGN;
524 * Flush all handlers for a task.
528 flush_signal_handlers(struct task_struct *t, int force_default)
531 struct k_sigaction *ka = &t->sighand->action[0];
532 for (i = _NSIG ; i != 0 ; i--) {
533 if (force_default || ka->sa.sa_handler != SIG_IGN)
534 ka->sa.sa_handler = SIG_DFL;
536 #ifdef __ARCH_HAS_SA_RESTORER
537 ka->sa.sa_restorer = NULL;
539 sigemptyset(&ka->sa.sa_mask);
544 bool unhandled_signal(struct task_struct *tsk, int sig)
546 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
547 if (is_global_init(tsk))
550 if (handler != SIG_IGN && handler != SIG_DFL)
553 /* if ptraced, let the tracer determine */
557 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
560 struct sigqueue *q, *first = NULL;
563 * Collect the siginfo appropriate to this signal. Check if
564 * there is another siginfo for the same signal.
566 list_for_each_entry(q, &list->list, list) {
567 if (q->info.si_signo == sig) {
574 sigdelset(&list->signal, sig);
578 list_del_init(&first->list);
579 copy_siginfo(info, &first->info);
582 (first->flags & SIGQUEUE_PREALLOC) &&
583 (info->si_code == SI_TIMER) &&
584 (info->si_sys_private);
586 __sigqueue_free(first);
589 * Ok, it wasn't in the queue. This must be
590 * a fast-pathed signal or we must have been
591 * out of queue space. So zero out the info.
594 info->si_signo = sig;
596 info->si_code = SI_USER;
602 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
603 kernel_siginfo_t *info, bool *resched_timer)
605 int sig = next_signal(pending, mask);
608 collect_signal(sig, pending, info, resched_timer);
613 * Dequeue a signal and return the element to the caller, which is
614 * expected to free it.
616 * All callers have to hold the siglock.
618 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
620 bool resched_timer = false;
623 /* We only dequeue private signals from ourselves, we don't let
624 * signalfd steal them
626 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
628 signr = __dequeue_signal(&tsk->signal->shared_pending,
629 mask, info, &resched_timer);
630 #ifdef CONFIG_POSIX_TIMERS
634 * itimers are process shared and we restart periodic
635 * itimers in the signal delivery path to prevent DoS
636 * attacks in the high resolution timer case. This is
637 * compliant with the old way of self-restarting
638 * itimers, as the SIGALRM is a legacy signal and only
639 * queued once. Changing the restart behaviour to
640 * restart the timer in the signal dequeue path is
641 * reducing the timer noise on heavy loaded !highres
644 if (unlikely(signr == SIGALRM)) {
645 struct hrtimer *tmr = &tsk->signal->real_timer;
647 if (!hrtimer_is_queued(tmr) &&
648 tsk->signal->it_real_incr != 0) {
649 hrtimer_forward(tmr, tmr->base->get_time(),
650 tsk->signal->it_real_incr);
651 hrtimer_restart(tmr);
661 if (unlikely(sig_kernel_stop(signr))) {
663 * Set a marker that we have dequeued a stop signal. Our
664 * caller might release the siglock and then the pending
665 * stop signal it is about to process is no longer in the
666 * pending bitmasks, but must still be cleared by a SIGCONT
667 * (and overruled by a SIGKILL). So those cases clear this
668 * shared flag after we've set it. Note that this flag may
669 * remain set after the signal we return is ignored or
670 * handled. That doesn't matter because its only purpose
671 * is to alert stop-signal processing code when another
672 * processor has come along and cleared the flag.
674 current->jobctl |= JOBCTL_STOP_DEQUEUED;
676 #ifdef CONFIG_POSIX_TIMERS
679 * Release the siglock to ensure proper locking order
680 * of timer locks outside of siglocks. Note, we leave
681 * irqs disabled here, since the posix-timers code is
682 * about to disable them again anyway.
684 spin_unlock(&tsk->sighand->siglock);
685 posixtimer_rearm(info);
686 spin_lock(&tsk->sighand->siglock);
688 /* Don't expose the si_sys_private value to userspace */
689 info->si_sys_private = 0;
694 EXPORT_SYMBOL_GPL(dequeue_signal);
696 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
698 struct task_struct *tsk = current;
699 struct sigpending *pending = &tsk->pending;
700 struct sigqueue *q, *sync = NULL;
703 * Might a synchronous signal be in the queue?
705 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
709 * Return the first synchronous signal in the queue.
711 list_for_each_entry(q, &pending->list, list) {
712 /* Synchronous signals have a postive si_code */
713 if ((q->info.si_code > SI_USER) &&
714 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
722 * Check if there is another siginfo for the same signal.
724 list_for_each_entry_continue(q, &pending->list, list) {
725 if (q->info.si_signo == sync->info.si_signo)
729 sigdelset(&pending->signal, sync->info.si_signo);
732 list_del_init(&sync->list);
733 copy_siginfo(info, &sync->info);
734 __sigqueue_free(sync);
735 return info->si_signo;
739 * Tell a process that it has a new active signal..
741 * NOTE! we rely on the previous spin_lock to
742 * lock interrupts for us! We can only be called with
743 * "siglock" held, and the local interrupt must
744 * have been disabled when that got acquired!
746 * No need to set need_resched since signal event passing
747 * goes through ->blocked
749 void signal_wake_up_state(struct task_struct *t, unsigned int state)
751 set_tsk_thread_flag(t, TIF_SIGPENDING);
753 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
754 * case. We don't check t->state here because there is a race with it
755 * executing another processor and just now entering stopped state.
756 * By using wake_up_state, we ensure the process will wake up and
757 * handle its death signal.
759 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
764 * Remove signals in mask from the pending set and queue.
765 * Returns 1 if any signals were found.
767 * All callers must be holding the siglock.
769 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
771 struct sigqueue *q, *n;
774 sigandsets(&m, mask, &s->signal);
775 if (sigisemptyset(&m))
778 sigandnsets(&s->signal, &s->signal, mask);
779 list_for_each_entry_safe(q, n, &s->list, list) {
780 if (sigismember(mask, q->info.si_signo)) {
781 list_del_init(&q->list);
787 static inline int is_si_special(const struct kernel_siginfo *info)
789 return info <= SEND_SIG_PRIV;
792 static inline bool si_fromuser(const struct kernel_siginfo *info)
794 return info == SEND_SIG_NOINFO ||
795 (!is_si_special(info) && SI_FROMUSER(info));
799 * called with RCU read lock from check_kill_permission()
801 static bool kill_ok_by_cred(struct task_struct *t)
803 const struct cred *cred = current_cred();
804 const struct cred *tcred = __task_cred(t);
806 return uid_eq(cred->euid, tcred->suid) ||
807 uid_eq(cred->euid, tcred->uid) ||
808 uid_eq(cred->uid, tcred->suid) ||
809 uid_eq(cred->uid, tcred->uid) ||
810 ns_capable(tcred->user_ns, CAP_KILL);
814 * Bad permissions for sending the signal
815 * - the caller must hold the RCU read lock
817 static int check_kill_permission(int sig, struct kernel_siginfo *info,
818 struct task_struct *t)
823 if (!valid_signal(sig))
826 if (!si_fromuser(info))
829 error = audit_signal_info(sig, t); /* Let audit system see the signal */
833 if (!same_thread_group(current, t) &&
834 !kill_ok_by_cred(t)) {
837 sid = task_session(t);
839 * We don't return the error if sid == NULL. The
840 * task was unhashed, the caller must notice this.
842 if (!sid || sid == task_session(current))
850 return security_task_kill(t, info, sig, NULL);
854 * ptrace_trap_notify - schedule trap to notify ptracer
855 * @t: tracee wanting to notify tracer
857 * This function schedules sticky ptrace trap which is cleared on the next
858 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
861 * If @t is running, STOP trap will be taken. If trapped for STOP and
862 * ptracer is listening for events, tracee is woken up so that it can
863 * re-trap for the new event. If trapped otherwise, STOP trap will be
864 * eventually taken without returning to userland after the existing traps
865 * are finished by PTRACE_CONT.
868 * Must be called with @task->sighand->siglock held.
870 static void ptrace_trap_notify(struct task_struct *t)
872 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
873 assert_spin_locked(&t->sighand->siglock);
875 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
876 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
880 * Handle magic process-wide effects of stop/continue signals. Unlike
881 * the signal actions, these happen immediately at signal-generation
882 * time regardless of blocking, ignoring, or handling. This does the
883 * actual continuing for SIGCONT, but not the actual stopping for stop
884 * signals. The process stop is done as a signal action for SIG_DFL.
886 * Returns true if the signal should be actually delivered, otherwise
887 * it should be dropped.
889 static bool prepare_signal(int sig, struct task_struct *p, bool force)
891 struct signal_struct *signal = p->signal;
892 struct task_struct *t;
895 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
896 if (!(signal->flags & SIGNAL_GROUP_EXIT))
897 return sig == SIGKILL;
899 * The process is in the middle of dying, nothing to do.
901 } else if (sig_kernel_stop(sig)) {
903 * This is a stop signal. Remove SIGCONT from all queues.
905 siginitset(&flush, sigmask(SIGCONT));
906 flush_sigqueue_mask(&flush, &signal->shared_pending);
907 for_each_thread(p, t)
908 flush_sigqueue_mask(&flush, &t->pending);
909 } else if (sig == SIGCONT) {
912 * Remove all stop signals from all queues, wake all threads.
914 siginitset(&flush, SIG_KERNEL_STOP_MASK);
915 flush_sigqueue_mask(&flush, &signal->shared_pending);
916 for_each_thread(p, t) {
917 flush_sigqueue_mask(&flush, &t->pending);
918 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
919 if (likely(!(t->ptrace & PT_SEIZED)))
920 wake_up_state(t, __TASK_STOPPED);
922 ptrace_trap_notify(t);
926 * Notify the parent with CLD_CONTINUED if we were stopped.
928 * If we were in the middle of a group stop, we pretend it
929 * was already finished, and then continued. Since SIGCHLD
930 * doesn't queue we report only CLD_STOPPED, as if the next
931 * CLD_CONTINUED was dropped.
934 if (signal->flags & SIGNAL_STOP_STOPPED)
935 why |= SIGNAL_CLD_CONTINUED;
936 else if (signal->group_stop_count)
937 why |= SIGNAL_CLD_STOPPED;
941 * The first thread which returns from do_signal_stop()
942 * will take ->siglock, notice SIGNAL_CLD_MASK, and
943 * notify its parent. See get_signal().
945 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
946 signal->group_stop_count = 0;
947 signal->group_exit_code = 0;
951 return !sig_ignored(p, sig, force);
955 * Test if P wants to take SIG. After we've checked all threads with this,
956 * it's equivalent to finding no threads not blocking SIG. Any threads not
957 * blocking SIG were ruled out because they are not running and already
958 * have pending signals. Such threads will dequeue from the shared queue
959 * as soon as they're available, so putting the signal on the shared queue
960 * will be equivalent to sending it to one such thread.
962 static inline bool wants_signal(int sig, struct task_struct *p)
964 if (sigismember(&p->blocked, sig))
967 if (p->flags & PF_EXITING)
973 if (task_is_stopped_or_traced(p))
976 return task_curr(p) || !signal_pending(p);
979 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
981 struct signal_struct *signal = p->signal;
982 struct task_struct *t;
985 * Now find a thread we can wake up to take the signal off the queue.
987 * If the main thread wants the signal, it gets first crack.
988 * Probably the least surprising to the average bear.
990 if (wants_signal(sig, p))
992 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
994 * There is just one thread and it does not need to be woken.
995 * It will dequeue unblocked signals before it runs again.
1000 * Otherwise try to find a suitable thread.
1002 t = signal->curr_target;
1003 while (!wants_signal(sig, t)) {
1005 if (t == signal->curr_target)
1007 * No thread needs to be woken.
1008 * Any eligible threads will see
1009 * the signal in the queue soon.
1013 signal->curr_target = t;
1017 * Found a killable thread. If the signal will be fatal,
1018 * then start taking the whole group down immediately.
1020 if (sig_fatal(p, sig) &&
1021 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1022 !sigismember(&t->real_blocked, sig) &&
1023 (sig == SIGKILL || !p->ptrace)) {
1025 * This signal will be fatal to the whole group.
1027 if (!sig_kernel_coredump(sig)) {
1029 * Start a group exit and wake everybody up.
1030 * This way we don't have other threads
1031 * running and doing things after a slower
1032 * thread has the fatal signal pending.
1034 signal->flags = SIGNAL_GROUP_EXIT;
1035 signal->group_exit_code = sig;
1036 signal->group_stop_count = 0;
1039 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1040 sigaddset(&t->pending.signal, SIGKILL);
1041 signal_wake_up(t, 1);
1042 } while_each_thread(p, t);
1048 * The signal is already in the shared-pending queue.
1049 * Tell the chosen thread to wake up and dequeue it.
1051 signal_wake_up(t, sig == SIGKILL);
1055 static inline bool legacy_queue(struct sigpending *signals, int sig)
1057 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1060 #ifdef CONFIG_USER_NS
1061 static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t)
1063 if (current_user_ns() == task_cred_xxx(t, user_ns))
1066 if (SI_FROMKERNEL(info))
1070 info->si_uid = from_kuid_munged(task_cred_xxx(t, user_ns),
1071 make_kuid(current_user_ns(), info->si_uid));
1075 static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t)
1081 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1082 enum pid_type type, int from_ancestor_ns)
1084 struct sigpending *pending;
1086 int override_rlimit;
1087 int ret = 0, result;
1089 assert_spin_locked(&t->sighand->siglock);
1091 result = TRACE_SIGNAL_IGNORED;
1092 if (!prepare_signal(sig, t,
1093 from_ancestor_ns || (info == SEND_SIG_PRIV)))
1096 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1098 * Short-circuit ignored signals and support queuing
1099 * exactly one non-rt signal, so that we can get more
1100 * detailed information about the cause of the signal.
1102 result = TRACE_SIGNAL_ALREADY_PENDING;
1103 if (legacy_queue(pending, sig))
1106 result = TRACE_SIGNAL_DELIVERED;
1108 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1110 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1114 * Real-time signals must be queued if sent by sigqueue, or
1115 * some other real-time mechanism. It is implementation
1116 * defined whether kill() does so. We attempt to do so, on
1117 * the principle of least surprise, but since kill is not
1118 * allowed to fail with EAGAIN when low on memory we just
1119 * make sure at least one signal gets delivered and don't
1120 * pass on the info struct.
1123 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1125 override_rlimit = 0;
1127 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
1129 list_add_tail(&q->list, &pending->list);
1130 switch ((unsigned long) info) {
1131 case (unsigned long) SEND_SIG_NOINFO:
1132 clear_siginfo(&q->info);
1133 q->info.si_signo = sig;
1134 q->info.si_errno = 0;
1135 q->info.si_code = SI_USER;
1136 q->info.si_pid = task_tgid_nr_ns(current,
1137 task_active_pid_ns(t));
1138 q->info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
1140 case (unsigned long) SEND_SIG_PRIV:
1141 clear_siginfo(&q->info);
1142 q->info.si_signo = sig;
1143 q->info.si_errno = 0;
1144 q->info.si_code = SI_KERNEL;
1149 copy_siginfo(&q->info, info);
1150 if (from_ancestor_ns)
1155 userns_fixup_signal_uid(&q->info, t);
1157 } else if (!is_si_special(info)) {
1158 if (sig >= SIGRTMIN && info->si_code != SI_USER) {
1160 * Queue overflow, abort. We may abort if the
1161 * signal was rt and sent by user using something
1162 * other than kill().
1164 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1169 * This is a silent loss of information. We still
1170 * send the signal, but the *info bits are lost.
1172 result = TRACE_SIGNAL_LOSE_INFO;
1177 signalfd_notify(t, sig);
1178 sigaddset(&pending->signal, sig);
1180 /* Let multiprocess signals appear after on-going forks */
1181 if (type > PIDTYPE_TGID) {
1182 struct multiprocess_signals *delayed;
1183 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1184 sigset_t *signal = &delayed->signal;
1185 /* Can't queue both a stop and a continue signal */
1187 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1188 else if (sig_kernel_stop(sig))
1189 sigdelset(signal, SIGCONT);
1190 sigaddset(signal, sig);
1194 complete_signal(sig, t, type);
1196 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1200 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1203 int from_ancestor_ns = 0;
1205 #ifdef CONFIG_PID_NS
1206 from_ancestor_ns = si_fromuser(info) &&
1207 !task_pid_nr_ns(current, task_active_pid_ns(t));
1210 return __send_signal(sig, info, t, type, from_ancestor_ns);
1213 static void print_fatal_signal(int signr)
1215 struct pt_regs *regs = signal_pt_regs();
1216 pr_info("potentially unexpected fatal signal %d.\n", signr);
1218 #if defined(__i386__) && !defined(__arch_um__)
1219 pr_info("code at %08lx: ", regs->ip);
1222 for (i = 0; i < 16; i++) {
1225 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1227 pr_cont("%02x ", insn);
1237 static int __init setup_print_fatal_signals(char *str)
1239 get_option (&str, &print_fatal_signals);
1244 __setup("print-fatal-signals=", setup_print_fatal_signals);
1247 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1249 return send_signal(sig, info, p, PIDTYPE_TGID);
1252 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1255 unsigned long flags;
1258 if (lock_task_sighand(p, &flags)) {
1259 ret = send_signal(sig, info, p, type);
1260 unlock_task_sighand(p, &flags);
1267 * Force a signal that the process can't ignore: if necessary
1268 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1270 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1271 * since we do not want to have a signal handler that was blocked
1272 * be invoked when user space had explicitly blocked it.
1274 * We don't want to have recursive SIGSEGV's etc, for example,
1275 * that is why we also clear SIGNAL_UNKILLABLE.
1278 force_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *t)
1280 unsigned long int flags;
1281 int ret, blocked, ignored;
1282 struct k_sigaction *action;
1284 spin_lock_irqsave(&t->sighand->siglock, flags);
1285 action = &t->sighand->action[sig-1];
1286 ignored = action->sa.sa_handler == SIG_IGN;
1287 blocked = sigismember(&t->blocked, sig);
1288 if (blocked || ignored) {
1289 action->sa.sa_handler = SIG_DFL;
1291 sigdelset(&t->blocked, sig);
1292 recalc_sigpending_and_wake(t);
1296 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1297 * debugging to leave init killable.
1299 if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
1300 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1301 ret = send_signal(sig, info, t, PIDTYPE_PID);
1302 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1308 * Nuke all other threads in the group.
1310 int zap_other_threads(struct task_struct *p)
1312 struct task_struct *t = p;
1315 p->signal->group_stop_count = 0;
1317 while_each_thread(p, t) {
1318 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1321 /* Don't bother with already dead threads */
1324 sigaddset(&t->pending.signal, SIGKILL);
1325 signal_wake_up(t, 1);
1331 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1332 unsigned long *flags)
1334 struct sighand_struct *sighand;
1338 sighand = rcu_dereference(tsk->sighand);
1339 if (unlikely(sighand == NULL))
1343 * This sighand can be already freed and even reused, but
1344 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1345 * initializes ->siglock: this slab can't go away, it has
1346 * the same object type, ->siglock can't be reinitialized.
1348 * We need to ensure that tsk->sighand is still the same
1349 * after we take the lock, we can race with de_thread() or
1350 * __exit_signal(). In the latter case the next iteration
1351 * must see ->sighand == NULL.
1353 spin_lock_irqsave(&sighand->siglock, *flags);
1354 if (likely(sighand == tsk->sighand))
1356 spin_unlock_irqrestore(&sighand->siglock, *flags);
1364 * send signal info to all the members of a group
1366 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1367 struct task_struct *p, enum pid_type type)
1372 ret = check_kill_permission(sig, info, p);
1376 ret = do_send_sig_info(sig, info, p, type);
1382 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1383 * control characters do (^C, ^Z etc)
1384 * - the caller must hold at least a readlock on tasklist_lock
1386 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1388 struct task_struct *p = NULL;
1389 int retval, success;
1393 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1394 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1397 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1398 return success ? 0 : retval;
1401 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1404 struct task_struct *p;
1408 p = pid_task(pid, PIDTYPE_PID);
1410 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1412 if (likely(!p || error != -ESRCH))
1416 * The task was unhashed in between, try again. If it
1417 * is dead, pid_task() will return NULL, if we race with
1418 * de_thread() it will find the new leader.
1423 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1427 error = kill_pid_info(sig, info, find_vpid(pid));
1432 static inline bool kill_as_cred_perm(const struct cred *cred,
1433 struct task_struct *target)
1435 const struct cred *pcred = __task_cred(target);
1437 return uid_eq(cred->euid, pcred->suid) ||
1438 uid_eq(cred->euid, pcred->uid) ||
1439 uid_eq(cred->uid, pcred->suid) ||
1440 uid_eq(cred->uid, pcred->uid);
1443 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1444 int kill_pid_info_as_cred(int sig, struct kernel_siginfo *info, struct pid *pid,
1445 const struct cred *cred)
1448 struct task_struct *p;
1449 unsigned long flags;
1451 if (!valid_signal(sig))
1455 p = pid_task(pid, PIDTYPE_PID);
1460 if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
1464 ret = security_task_kill(p, info, sig, cred);
1469 if (lock_task_sighand(p, &flags)) {
1470 ret = __send_signal(sig, info, p, PIDTYPE_TGID, 0);
1471 unlock_task_sighand(p, &flags);
1479 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
1482 * kill_something_info() interprets pid in interesting ways just like kill(2).
1484 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1485 * is probably wrong. Should make it like BSD or SYSV.
1488 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1494 ret = kill_pid_info(sig, info, find_vpid(pid));
1499 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1503 read_lock(&tasklist_lock);
1505 ret = __kill_pgrp_info(sig, info,
1506 pid ? find_vpid(-pid) : task_pgrp(current));
1508 int retval = 0, count = 0;
1509 struct task_struct * p;
1511 for_each_process(p) {
1512 if (task_pid_vnr(p) > 1 &&
1513 !same_thread_group(p, current)) {
1514 int err = group_send_sig_info(sig, info, p,
1521 ret = count ? retval : -ESRCH;
1523 read_unlock(&tasklist_lock);
1529 * These are for backward compatibility with the rest of the kernel source.
1532 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1535 * Make sure legacy kernel users don't send in bad values
1536 * (normal paths check this in check_kill_permission).
1538 if (!valid_signal(sig))
1541 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1543 EXPORT_SYMBOL(send_sig_info);
1545 #define __si_special(priv) \
1546 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1549 send_sig(int sig, struct task_struct *p, int priv)
1551 return send_sig_info(sig, __si_special(priv), p);
1553 EXPORT_SYMBOL(send_sig);
1555 void force_sig(int sig, struct task_struct *p)
1557 force_sig_info(sig, SEND_SIG_PRIV, p);
1559 EXPORT_SYMBOL(force_sig);
1562 * When things go south during signal handling, we
1563 * will force a SIGSEGV. And if the signal that caused
1564 * the problem was already a SIGSEGV, we'll want to
1565 * make sure we don't even try to deliver the signal..
1567 void force_sigsegv(int sig, struct task_struct *p)
1569 if (sig == SIGSEGV) {
1570 unsigned long flags;
1571 spin_lock_irqsave(&p->sighand->siglock, flags);
1572 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1573 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1575 force_sig(SIGSEGV, p);
1578 int force_sig_fault(int sig, int code, void __user *addr
1579 ___ARCH_SI_TRAPNO(int trapno)
1580 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1581 , struct task_struct *t)
1583 struct kernel_siginfo info;
1585 clear_siginfo(&info);
1586 info.si_signo = sig;
1588 info.si_code = code;
1589 info.si_addr = addr;
1590 #ifdef __ARCH_SI_TRAPNO
1591 info.si_trapno = trapno;
1595 info.si_flags = flags;
1598 return force_sig_info(info.si_signo, &info, t);
1601 int send_sig_fault(int sig, int code, void __user *addr
1602 ___ARCH_SI_TRAPNO(int trapno)
1603 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1604 , struct task_struct *t)
1606 struct kernel_siginfo info;
1608 clear_siginfo(&info);
1609 info.si_signo = sig;
1611 info.si_code = code;
1612 info.si_addr = addr;
1613 #ifdef __ARCH_SI_TRAPNO
1614 info.si_trapno = trapno;
1618 info.si_flags = flags;
1621 return send_sig_info(info.si_signo, &info, t);
1624 int force_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1626 struct kernel_siginfo info;
1628 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1629 clear_siginfo(&info);
1630 info.si_signo = SIGBUS;
1632 info.si_code = code;
1633 info.si_addr = addr;
1634 info.si_addr_lsb = lsb;
1635 return force_sig_info(info.si_signo, &info, t);
1638 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1640 struct kernel_siginfo info;
1642 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1643 clear_siginfo(&info);
1644 info.si_signo = SIGBUS;
1646 info.si_code = code;
1647 info.si_addr = addr;
1648 info.si_addr_lsb = lsb;
1649 return send_sig_info(info.si_signo, &info, t);
1651 EXPORT_SYMBOL(send_sig_mceerr);
1653 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1655 struct kernel_siginfo info;
1657 clear_siginfo(&info);
1658 info.si_signo = SIGSEGV;
1660 info.si_code = SEGV_BNDERR;
1661 info.si_addr = addr;
1662 info.si_lower = lower;
1663 info.si_upper = upper;
1664 return force_sig_info(info.si_signo, &info, current);
1668 int force_sig_pkuerr(void __user *addr, u32 pkey)
1670 struct kernel_siginfo info;
1672 clear_siginfo(&info);
1673 info.si_signo = SIGSEGV;
1675 info.si_code = SEGV_PKUERR;
1676 info.si_addr = addr;
1677 info.si_pkey = pkey;
1678 return force_sig_info(info.si_signo, &info, current);
1682 /* For the crazy architectures that include trap information in
1683 * the errno field, instead of an actual errno value.
1685 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1687 struct kernel_siginfo info;
1689 clear_siginfo(&info);
1690 info.si_signo = SIGTRAP;
1691 info.si_errno = errno;
1692 info.si_code = TRAP_HWBKPT;
1693 info.si_addr = addr;
1694 return force_sig_info(info.si_signo, &info, current);
1697 int kill_pgrp(struct pid *pid, int sig, int priv)
1701 read_lock(&tasklist_lock);
1702 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1703 read_unlock(&tasklist_lock);
1707 EXPORT_SYMBOL(kill_pgrp);
1709 int kill_pid(struct pid *pid, int sig, int priv)
1711 return kill_pid_info(sig, __si_special(priv), pid);
1713 EXPORT_SYMBOL(kill_pid);
1716 * These functions support sending signals using preallocated sigqueue
1717 * structures. This is needed "because realtime applications cannot
1718 * afford to lose notifications of asynchronous events, like timer
1719 * expirations or I/O completions". In the case of POSIX Timers
1720 * we allocate the sigqueue structure from the timer_create. If this
1721 * allocation fails we are able to report the failure to the application
1722 * with an EAGAIN error.
1724 struct sigqueue *sigqueue_alloc(void)
1726 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1729 q->flags |= SIGQUEUE_PREALLOC;
1734 void sigqueue_free(struct sigqueue *q)
1736 unsigned long flags;
1737 spinlock_t *lock = ¤t->sighand->siglock;
1739 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1741 * We must hold ->siglock while testing q->list
1742 * to serialize with collect_signal() or with
1743 * __exit_signal()->flush_sigqueue().
1745 spin_lock_irqsave(lock, flags);
1746 q->flags &= ~SIGQUEUE_PREALLOC;
1748 * If it is queued it will be freed when dequeued,
1749 * like the "regular" sigqueue.
1751 if (!list_empty(&q->list))
1753 spin_unlock_irqrestore(lock, flags);
1759 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1761 int sig = q->info.si_signo;
1762 struct sigpending *pending;
1763 struct task_struct *t;
1764 unsigned long flags;
1767 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1771 t = pid_task(pid, type);
1772 if (!t || !likely(lock_task_sighand(t, &flags)))
1775 ret = 1; /* the signal is ignored */
1776 result = TRACE_SIGNAL_IGNORED;
1777 if (!prepare_signal(sig, t, false))
1781 if (unlikely(!list_empty(&q->list))) {
1783 * If an SI_TIMER entry is already queue just increment
1784 * the overrun count.
1786 BUG_ON(q->info.si_code != SI_TIMER);
1787 q->info.si_overrun++;
1788 result = TRACE_SIGNAL_ALREADY_PENDING;
1791 q->info.si_overrun = 0;
1793 signalfd_notify(t, sig);
1794 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1795 list_add_tail(&q->list, &pending->list);
1796 sigaddset(&pending->signal, sig);
1797 complete_signal(sig, t, type);
1798 result = TRACE_SIGNAL_DELIVERED;
1800 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
1801 unlock_task_sighand(t, &flags);
1808 * Let a parent know about the death of a child.
1809 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1811 * Returns true if our parent ignored us and so we've switched to
1814 bool do_notify_parent(struct task_struct *tsk, int sig)
1816 struct kernel_siginfo info;
1817 unsigned long flags;
1818 struct sighand_struct *psig;
1819 bool autoreap = false;
1824 /* do_notify_parent_cldstop should have been called instead. */
1825 BUG_ON(task_is_stopped_or_traced(tsk));
1827 BUG_ON(!tsk->ptrace &&
1828 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1830 if (sig != SIGCHLD) {
1832 * This is only possible if parent == real_parent.
1833 * Check if it has changed security domain.
1835 if (tsk->parent_exec_id != tsk->parent->self_exec_id)
1839 clear_siginfo(&info);
1840 info.si_signo = sig;
1843 * We are under tasklist_lock here so our parent is tied to
1844 * us and cannot change.
1846 * task_active_pid_ns will always return the same pid namespace
1847 * until a task passes through release_task.
1849 * write_lock() currently calls preempt_disable() which is the
1850 * same as rcu_read_lock(), but according to Oleg, this is not
1851 * correct to rely on this
1854 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1855 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1859 task_cputime(tsk, &utime, &stime);
1860 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
1861 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
1863 info.si_status = tsk->exit_code & 0x7f;
1864 if (tsk->exit_code & 0x80)
1865 info.si_code = CLD_DUMPED;
1866 else if (tsk->exit_code & 0x7f)
1867 info.si_code = CLD_KILLED;
1869 info.si_code = CLD_EXITED;
1870 info.si_status = tsk->exit_code >> 8;
1873 psig = tsk->parent->sighand;
1874 spin_lock_irqsave(&psig->siglock, flags);
1875 if (!tsk->ptrace && sig == SIGCHLD &&
1876 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1877 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1879 * We are exiting and our parent doesn't care. POSIX.1
1880 * defines special semantics for setting SIGCHLD to SIG_IGN
1881 * or setting the SA_NOCLDWAIT flag: we should be reaped
1882 * automatically and not left for our parent's wait4 call.
1883 * Rather than having the parent do it as a magic kind of
1884 * signal handler, we just set this to tell do_exit that we
1885 * can be cleaned up without becoming a zombie. Note that
1886 * we still call __wake_up_parent in this case, because a
1887 * blocked sys_wait4 might now return -ECHILD.
1889 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1890 * is implementation-defined: we do (if you don't want
1891 * it, just use SIG_IGN instead).
1894 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1897 if (valid_signal(sig) && sig)
1898 __group_send_sig_info(sig, &info, tsk->parent);
1899 __wake_up_parent(tsk, tsk->parent);
1900 spin_unlock_irqrestore(&psig->siglock, flags);
1906 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1907 * @tsk: task reporting the state change
1908 * @for_ptracer: the notification is for ptracer
1909 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1911 * Notify @tsk's parent that the stopped/continued state has changed. If
1912 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1913 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1916 * Must be called with tasklist_lock at least read locked.
1918 static void do_notify_parent_cldstop(struct task_struct *tsk,
1919 bool for_ptracer, int why)
1921 struct kernel_siginfo info;
1922 unsigned long flags;
1923 struct task_struct *parent;
1924 struct sighand_struct *sighand;
1928 parent = tsk->parent;
1930 tsk = tsk->group_leader;
1931 parent = tsk->real_parent;
1934 clear_siginfo(&info);
1935 info.si_signo = SIGCHLD;
1938 * see comment in do_notify_parent() about the following 4 lines
1941 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
1942 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
1945 task_cputime(tsk, &utime, &stime);
1946 info.si_utime = nsec_to_clock_t(utime);
1947 info.si_stime = nsec_to_clock_t(stime);
1952 info.si_status = SIGCONT;
1955 info.si_status = tsk->signal->group_exit_code & 0x7f;
1958 info.si_status = tsk->exit_code & 0x7f;
1964 sighand = parent->sighand;
1965 spin_lock_irqsave(&sighand->siglock, flags);
1966 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
1967 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
1968 __group_send_sig_info(SIGCHLD, &info, parent);
1970 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1972 __wake_up_parent(tsk, parent);
1973 spin_unlock_irqrestore(&sighand->siglock, flags);
1976 static inline bool may_ptrace_stop(void)
1978 if (!likely(current->ptrace))
1981 * Are we in the middle of do_coredump?
1982 * If so and our tracer is also part of the coredump stopping
1983 * is a deadlock situation, and pointless because our tracer
1984 * is dead so don't allow us to stop.
1985 * If SIGKILL was already sent before the caller unlocked
1986 * ->siglock we must see ->core_state != NULL. Otherwise it
1987 * is safe to enter schedule().
1989 * This is almost outdated, a task with the pending SIGKILL can't
1990 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1991 * after SIGKILL was already dequeued.
1993 if (unlikely(current->mm->core_state) &&
1994 unlikely(current->mm == current->parent->mm))
2001 * Return non-zero if there is a SIGKILL that should be waking us up.
2002 * Called with the siglock held.
2004 static bool sigkill_pending(struct task_struct *tsk)
2006 return sigismember(&tsk->pending.signal, SIGKILL) ||
2007 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
2011 * This must be called with current->sighand->siglock held.
2013 * This should be the path for all ptrace stops.
2014 * We always set current->last_siginfo while stopped here.
2015 * That makes it a way to test a stopped process for
2016 * being ptrace-stopped vs being job-control-stopped.
2018 * If we actually decide not to stop at all because the tracer
2019 * is gone, we keep current->exit_code unless clear_code.
2021 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2022 __releases(¤t->sighand->siglock)
2023 __acquires(¤t->sighand->siglock)
2025 bool gstop_done = false;
2027 if (arch_ptrace_stop_needed(exit_code, info)) {
2029 * The arch code has something special to do before a
2030 * ptrace stop. This is allowed to block, e.g. for faults
2031 * on user stack pages. We can't keep the siglock while
2032 * calling arch_ptrace_stop, so we must release it now.
2033 * To preserve proper semantics, we must do this before
2034 * any signal bookkeeping like checking group_stop_count.
2035 * Meanwhile, a SIGKILL could come in before we retake the
2036 * siglock. That must prevent us from sleeping in TASK_TRACED.
2037 * So after regaining the lock, we must check for SIGKILL.
2039 spin_unlock_irq(¤t->sighand->siglock);
2040 arch_ptrace_stop(exit_code, info);
2041 spin_lock_irq(¤t->sighand->siglock);
2042 if (sigkill_pending(current))
2046 set_special_state(TASK_TRACED);
2049 * We're committing to trapping. TRACED should be visible before
2050 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2051 * Also, transition to TRACED and updates to ->jobctl should be
2052 * atomic with respect to siglock and should be done after the arch
2053 * hook as siglock is released and regrabbed across it.
2058 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2060 * set_current_state() smp_wmb();
2062 * wait_task_stopped()
2063 * task_stopped_code()
2064 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2068 current->last_siginfo = info;
2069 current->exit_code = exit_code;
2072 * If @why is CLD_STOPPED, we're trapping to participate in a group
2073 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2074 * across siglock relocks since INTERRUPT was scheduled, PENDING
2075 * could be clear now. We act as if SIGCONT is received after
2076 * TASK_TRACED is entered - ignore it.
2078 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2079 gstop_done = task_participate_group_stop(current);
2081 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2082 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2083 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2084 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2086 /* entering a trap, clear TRAPPING */
2087 task_clear_jobctl_trapping(current);
2089 spin_unlock_irq(¤t->sighand->siglock);
2090 read_lock(&tasklist_lock);
2091 if (may_ptrace_stop()) {
2093 * Notify parents of the stop.
2095 * While ptraced, there are two parents - the ptracer and
2096 * the real_parent of the group_leader. The ptracer should
2097 * know about every stop while the real parent is only
2098 * interested in the completion of group stop. The states
2099 * for the two don't interact with each other. Notify
2100 * separately unless they're gonna be duplicates.
2102 do_notify_parent_cldstop(current, true, why);
2103 if (gstop_done && ptrace_reparented(current))
2104 do_notify_parent_cldstop(current, false, why);
2107 * Don't want to allow preemption here, because
2108 * sys_ptrace() needs this task to be inactive.
2110 * XXX: implement read_unlock_no_resched().
2113 read_unlock(&tasklist_lock);
2114 preempt_enable_no_resched();
2115 cgroup_enter_frozen();
2116 freezable_schedule();
2117 cgroup_leave_frozen(true);
2120 * By the time we got the lock, our tracer went away.
2121 * Don't drop the lock yet, another tracer may come.
2123 * If @gstop_done, the ptracer went away between group stop
2124 * completion and here. During detach, it would have set
2125 * JOBCTL_STOP_PENDING on us and we'll re-enter
2126 * TASK_STOPPED in do_signal_stop() on return, so notifying
2127 * the real parent of the group stop completion is enough.
2130 do_notify_parent_cldstop(current, false, why);
2132 /* tasklist protects us from ptrace_freeze_traced() */
2133 __set_current_state(TASK_RUNNING);
2135 current->exit_code = 0;
2136 read_unlock(&tasklist_lock);
2140 * We are back. Now reacquire the siglock before touching
2141 * last_siginfo, so that we are sure to have synchronized with
2142 * any signal-sending on another CPU that wants to examine it.
2144 spin_lock_irq(¤t->sighand->siglock);
2145 current->last_siginfo = NULL;
2147 /* LISTENING can be set only during STOP traps, clear it */
2148 current->jobctl &= ~JOBCTL_LISTENING;
2151 * Queued signals ignored us while we were stopped for tracing.
2152 * So check for any that we should take before resuming user mode.
2153 * This sets TIF_SIGPENDING, but never clears it.
2155 recalc_sigpending_tsk(current);
2158 static void ptrace_do_notify(int signr, int exit_code, int why)
2160 kernel_siginfo_t info;
2162 clear_siginfo(&info);
2163 info.si_signo = signr;
2164 info.si_code = exit_code;
2165 info.si_pid = task_pid_vnr(current);
2166 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2168 /* Let the debugger run. */
2169 ptrace_stop(exit_code, why, 1, &info);
2172 void ptrace_notify(int exit_code)
2174 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2175 if (unlikely(current->task_works))
2178 spin_lock_irq(¤t->sighand->siglock);
2179 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2180 spin_unlock_irq(¤t->sighand->siglock);
2184 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2185 * @signr: signr causing group stop if initiating
2187 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2188 * and participate in it. If already set, participate in the existing
2189 * group stop. If participated in a group stop (and thus slept), %true is
2190 * returned with siglock released.
2192 * If ptraced, this function doesn't handle stop itself. Instead,
2193 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2194 * untouched. The caller must ensure that INTERRUPT trap handling takes
2195 * places afterwards.
2198 * Must be called with @current->sighand->siglock held, which is released
2202 * %false if group stop is already cancelled or ptrace trap is scheduled.
2203 * %true if participated in group stop.
2205 static bool do_signal_stop(int signr)
2206 __releases(¤t->sighand->siglock)
2208 struct signal_struct *sig = current->signal;
2210 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2211 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2212 struct task_struct *t;
2214 /* signr will be recorded in task->jobctl for retries */
2215 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2217 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2218 unlikely(signal_group_exit(sig)))
2221 * There is no group stop already in progress. We must
2224 * While ptraced, a task may be resumed while group stop is
2225 * still in effect and then receive a stop signal and
2226 * initiate another group stop. This deviates from the
2227 * usual behavior as two consecutive stop signals can't
2228 * cause two group stops when !ptraced. That is why we
2229 * also check !task_is_stopped(t) below.
2231 * The condition can be distinguished by testing whether
2232 * SIGNAL_STOP_STOPPED is already set. Don't generate
2233 * group_exit_code in such case.
2235 * This is not necessary for SIGNAL_STOP_CONTINUED because
2236 * an intervening stop signal is required to cause two
2237 * continued events regardless of ptrace.
2239 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2240 sig->group_exit_code = signr;
2242 sig->group_stop_count = 0;
2244 if (task_set_jobctl_pending(current, signr | gstop))
2245 sig->group_stop_count++;
2248 while_each_thread(current, t) {
2250 * Setting state to TASK_STOPPED for a group
2251 * stop is always done with the siglock held,
2252 * so this check has no races.
2254 if (!task_is_stopped(t) &&
2255 task_set_jobctl_pending(t, signr | gstop)) {
2256 sig->group_stop_count++;
2257 if (likely(!(t->ptrace & PT_SEIZED)))
2258 signal_wake_up(t, 0);
2260 ptrace_trap_notify(t);
2265 if (likely(!current->ptrace)) {
2269 * If there are no other threads in the group, or if there
2270 * is a group stop in progress and we are the last to stop,
2271 * report to the parent.
2273 if (task_participate_group_stop(current))
2274 notify = CLD_STOPPED;
2276 set_special_state(TASK_STOPPED);
2277 spin_unlock_irq(¤t->sighand->siglock);
2280 * Notify the parent of the group stop completion. Because
2281 * we're not holding either the siglock or tasklist_lock
2282 * here, ptracer may attach inbetween; however, this is for
2283 * group stop and should always be delivered to the real
2284 * parent of the group leader. The new ptracer will get
2285 * its notification when this task transitions into
2289 read_lock(&tasklist_lock);
2290 do_notify_parent_cldstop(current, false, notify);
2291 read_unlock(&tasklist_lock);
2294 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2295 cgroup_enter_frozen();
2296 freezable_schedule();
2300 * While ptraced, group stop is handled by STOP trap.
2301 * Schedule it and let the caller deal with it.
2303 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2309 * do_jobctl_trap - take care of ptrace jobctl traps
2311 * When PT_SEIZED, it's used for both group stop and explicit
2312 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2313 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2314 * the stop signal; otherwise, %SIGTRAP.
2316 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2317 * number as exit_code and no siginfo.
2320 * Must be called with @current->sighand->siglock held, which may be
2321 * released and re-acquired before returning with intervening sleep.
2323 static void do_jobctl_trap(void)
2325 struct signal_struct *signal = current->signal;
2326 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2328 if (current->ptrace & PT_SEIZED) {
2329 if (!signal->group_stop_count &&
2330 !(signal->flags & SIGNAL_STOP_STOPPED))
2332 WARN_ON_ONCE(!signr);
2333 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2336 WARN_ON_ONCE(!signr);
2337 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2338 current->exit_code = 0;
2343 * do_freezer_trap - handle the freezer jobctl trap
2345 * Puts the task into frozen state, if only the task is not about to quit.
2346 * In this case it drops JOBCTL_TRAP_FREEZE.
2349 * Must be called with @current->sighand->siglock held,
2350 * which is always released before returning.
2352 static void do_freezer_trap(void)
2353 __releases(¤t->sighand->siglock)
2356 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2357 * let's make another loop to give it a chance to be handled.
2358 * In any case, we'll return back.
2360 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2361 JOBCTL_TRAP_FREEZE) {
2362 spin_unlock_irq(¤t->sighand->siglock);
2367 * Now we're sure that there is no pending fatal signal and no
2368 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2369 * immediately (if there is a non-fatal signal pending), and
2370 * put the task into sleep.
2372 __set_current_state(TASK_INTERRUPTIBLE);
2373 clear_thread_flag(TIF_SIGPENDING);
2374 spin_unlock_irq(¤t->sighand->siglock);
2375 cgroup_enter_frozen();
2376 freezable_schedule();
2379 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2382 * We do not check sig_kernel_stop(signr) but set this marker
2383 * unconditionally because we do not know whether debugger will
2384 * change signr. This flag has no meaning unless we are going
2385 * to stop after return from ptrace_stop(). In this case it will
2386 * be checked in do_signal_stop(), we should only stop if it was
2387 * not cleared by SIGCONT while we were sleeping. See also the
2388 * comment in dequeue_signal().
2390 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2391 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2393 /* We're back. Did the debugger cancel the sig? */
2394 signr = current->exit_code;
2398 current->exit_code = 0;
2401 * Update the siginfo structure if the signal has
2402 * changed. If the debugger wanted something
2403 * specific in the siginfo structure then it should
2404 * have updated *info via PTRACE_SETSIGINFO.
2406 if (signr != info->si_signo) {
2407 clear_siginfo(info);
2408 info->si_signo = signr;
2410 info->si_code = SI_USER;
2412 info->si_pid = task_pid_vnr(current->parent);
2413 info->si_uid = from_kuid_munged(current_user_ns(),
2414 task_uid(current->parent));
2418 /* If the (new) signal is now blocked, requeue it. */
2419 if (sigismember(¤t->blocked, signr)) {
2420 send_signal(signr, info, current, PIDTYPE_PID);
2427 bool get_signal(struct ksignal *ksig)
2429 struct sighand_struct *sighand = current->sighand;
2430 struct signal_struct *signal = current->signal;
2433 if (unlikely(current->task_works))
2436 if (unlikely(uprobe_deny_signal()))
2440 * Do this once, we can't return to user-mode if freezing() == T.
2441 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2442 * thus do not need another check after return.
2447 spin_lock_irq(&sighand->siglock);
2449 * Every stopped thread goes here after wakeup. Check to see if
2450 * we should notify the parent, prepare_signal(SIGCONT) encodes
2451 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2453 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2456 if (signal->flags & SIGNAL_CLD_CONTINUED)
2457 why = CLD_CONTINUED;
2461 signal->flags &= ~SIGNAL_CLD_MASK;
2463 spin_unlock_irq(&sighand->siglock);
2466 * Notify the parent that we're continuing. This event is
2467 * always per-process and doesn't make whole lot of sense
2468 * for ptracers, who shouldn't consume the state via
2469 * wait(2) either, but, for backward compatibility, notify
2470 * the ptracer of the group leader too unless it's gonna be
2473 read_lock(&tasklist_lock);
2474 do_notify_parent_cldstop(current, false, why);
2476 if (ptrace_reparented(current->group_leader))
2477 do_notify_parent_cldstop(current->group_leader,
2479 read_unlock(&tasklist_lock);
2484 /* Has this task already been marked for death? */
2485 if (signal_group_exit(signal)) {
2486 ksig->info.si_signo = signr = SIGKILL;
2487 sigdelset(¤t->pending.signal, SIGKILL);
2488 recalc_sigpending();
2493 struct k_sigaction *ka;
2495 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2499 if (unlikely(current->jobctl &
2500 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2501 if (current->jobctl & JOBCTL_TRAP_MASK) {
2503 spin_unlock_irq(&sighand->siglock);
2504 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2511 * If the task is leaving the frozen state, let's update
2512 * cgroup counters and reset the frozen bit.
2514 if (unlikely(cgroup_task_frozen(current))) {
2515 spin_unlock_irq(&sighand->siglock);
2516 cgroup_leave_frozen(false);
2521 * Signals generated by the execution of an instruction
2522 * need to be delivered before any other pending signals
2523 * so that the instruction pointer in the signal stack
2524 * frame points to the faulting instruction.
2526 signr = dequeue_synchronous_signal(&ksig->info);
2528 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2531 break; /* will return 0 */
2533 if (unlikely(current->ptrace) && signr != SIGKILL) {
2534 signr = ptrace_signal(signr, &ksig->info);
2539 ka = &sighand->action[signr-1];
2541 /* Trace actually delivered signals. */
2542 trace_signal_deliver(signr, &ksig->info, ka);
2544 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2546 if (ka->sa.sa_handler != SIG_DFL) {
2547 /* Run the handler. */
2550 if (ka->sa.sa_flags & SA_ONESHOT)
2551 ka->sa.sa_handler = SIG_DFL;
2553 break; /* will return non-zero "signr" value */
2557 * Now we are doing the default action for this signal.
2559 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2563 * Global init gets no signals it doesn't want.
2564 * Container-init gets no signals it doesn't want from same
2567 * Note that if global/container-init sees a sig_kernel_only()
2568 * signal here, the signal must have been generated internally
2569 * or must have come from an ancestor namespace. In either
2570 * case, the signal cannot be dropped.
2572 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2573 !sig_kernel_only(signr))
2576 if (sig_kernel_stop(signr)) {
2578 * The default action is to stop all threads in
2579 * the thread group. The job control signals
2580 * do nothing in an orphaned pgrp, but SIGSTOP
2581 * always works. Note that siglock needs to be
2582 * dropped during the call to is_orphaned_pgrp()
2583 * because of lock ordering with tasklist_lock.
2584 * This allows an intervening SIGCONT to be posted.
2585 * We need to check for that and bail out if necessary.
2587 if (signr != SIGSTOP) {
2588 spin_unlock_irq(&sighand->siglock);
2590 /* signals can be posted during this window */
2592 if (is_current_pgrp_orphaned())
2595 spin_lock_irq(&sighand->siglock);
2598 if (likely(do_signal_stop(ksig->info.si_signo))) {
2599 /* It released the siglock. */
2604 * We didn't actually stop, due to a race
2605 * with SIGCONT or something like that.
2611 spin_unlock_irq(&sighand->siglock);
2612 if (unlikely(cgroup_task_frozen(current)))
2613 cgroup_leave_frozen(true);
2616 * Anything else is fatal, maybe with a core dump.
2618 current->flags |= PF_SIGNALED;
2620 if (sig_kernel_coredump(signr)) {
2621 if (print_fatal_signals)
2622 print_fatal_signal(ksig->info.si_signo);
2623 proc_coredump_connector(current);
2625 * If it was able to dump core, this kills all
2626 * other threads in the group and synchronizes with
2627 * their demise. If we lost the race with another
2628 * thread getting here, it set group_exit_code
2629 * first and our do_group_exit call below will use
2630 * that value and ignore the one we pass it.
2632 do_coredump(&ksig->info);
2636 * Death signals, no core dump.
2638 do_group_exit(ksig->info.si_signo);
2641 spin_unlock_irq(&sighand->siglock);
2644 return ksig->sig > 0;
2648 * signal_delivered -
2649 * @ksig: kernel signal struct
2650 * @stepping: nonzero if debugger single-step or block-step in use
2652 * This function should be called when a signal has successfully been
2653 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2654 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2655 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2657 static void signal_delivered(struct ksignal *ksig, int stepping)
2661 /* A signal was successfully delivered, and the
2662 saved sigmask was stored on the signal frame,
2663 and will be restored by sigreturn. So we can
2664 simply clear the restore sigmask flag. */
2665 clear_restore_sigmask();
2667 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2668 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2669 sigaddset(&blocked, ksig->sig);
2670 set_current_blocked(&blocked);
2671 tracehook_signal_handler(stepping);
2674 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2677 force_sigsegv(ksig->sig, current);
2679 signal_delivered(ksig, stepping);
2683 * It could be that complete_signal() picked us to notify about the
2684 * group-wide signal. Other threads should be notified now to take
2685 * the shared signals in @which since we will not.
2687 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2690 struct task_struct *t;
2692 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2693 if (sigisemptyset(&retarget))
2697 while_each_thread(tsk, t) {
2698 if (t->flags & PF_EXITING)
2701 if (!has_pending_signals(&retarget, &t->blocked))
2703 /* Remove the signals this thread can handle. */
2704 sigandsets(&retarget, &retarget, &t->blocked);
2706 if (!signal_pending(t))
2707 signal_wake_up(t, 0);
2709 if (sigisemptyset(&retarget))
2714 void exit_signals(struct task_struct *tsk)
2720 * @tsk is about to have PF_EXITING set - lock out users which
2721 * expect stable threadgroup.
2723 cgroup_threadgroup_change_begin(tsk);
2725 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2726 tsk->flags |= PF_EXITING;
2727 cgroup_threadgroup_change_end(tsk);
2731 spin_lock_irq(&tsk->sighand->siglock);
2733 * From now this task is not visible for group-wide signals,
2734 * see wants_signal(), do_signal_stop().
2736 tsk->flags |= PF_EXITING;
2738 cgroup_threadgroup_change_end(tsk);
2740 if (!signal_pending(tsk))
2743 unblocked = tsk->blocked;
2744 signotset(&unblocked);
2745 retarget_shared_pending(tsk, &unblocked);
2747 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2748 task_participate_group_stop(tsk))
2749 group_stop = CLD_STOPPED;
2751 spin_unlock_irq(&tsk->sighand->siglock);
2754 * If group stop has completed, deliver the notification. This
2755 * should always go to the real parent of the group leader.
2757 if (unlikely(group_stop)) {
2758 read_lock(&tasklist_lock);
2759 do_notify_parent_cldstop(tsk, false, group_stop);
2760 read_unlock(&tasklist_lock);
2765 * System call entry points.
2769 * sys_restart_syscall - restart a system call
2771 SYSCALL_DEFINE0(restart_syscall)
2773 struct restart_block *restart = ¤t->restart_block;
2774 return restart->fn(restart);
2777 long do_no_restart_syscall(struct restart_block *param)
2782 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2784 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2785 sigset_t newblocked;
2786 /* A set of now blocked but previously unblocked signals. */
2787 sigandnsets(&newblocked, newset, ¤t->blocked);
2788 retarget_shared_pending(tsk, &newblocked);
2790 tsk->blocked = *newset;
2791 recalc_sigpending();
2795 * set_current_blocked - change current->blocked mask
2798 * It is wrong to change ->blocked directly, this helper should be used
2799 * to ensure the process can't miss a shared signal we are going to block.
2801 void set_current_blocked(sigset_t *newset)
2803 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2804 __set_current_blocked(newset);
2807 void __set_current_blocked(const sigset_t *newset)
2809 struct task_struct *tsk = current;
2812 * In case the signal mask hasn't changed, there is nothing we need
2813 * to do. The current->blocked shouldn't be modified by other task.
2815 if (sigequalsets(&tsk->blocked, newset))
2818 spin_lock_irq(&tsk->sighand->siglock);
2819 __set_task_blocked(tsk, newset);
2820 spin_unlock_irq(&tsk->sighand->siglock);
2824 * This is also useful for kernel threads that want to temporarily
2825 * (or permanently) block certain signals.
2827 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2828 * interface happily blocks "unblockable" signals like SIGKILL
2831 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2833 struct task_struct *tsk = current;
2836 /* Lockless, only current can change ->blocked, never from irq */
2838 *oldset = tsk->blocked;
2842 sigorsets(&newset, &tsk->blocked, set);
2845 sigandnsets(&newset, &tsk->blocked, set);
2854 __set_current_blocked(&newset);
2857 EXPORT_SYMBOL(sigprocmask);
2860 * The api helps set app-provided sigmasks.
2862 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2863 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
2865 int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set,
2866 sigset_t *oldset, size_t sigsetsize)
2871 if (sigsetsize != sizeof(sigset_t))
2873 if (copy_from_user(set, usigmask, sizeof(sigset_t)))
2876 *oldset = current->blocked;
2877 set_current_blocked(set);
2881 EXPORT_SYMBOL(set_user_sigmask);
2883 #ifdef CONFIG_COMPAT
2884 int set_compat_user_sigmask(const compat_sigset_t __user *usigmask,
2885 sigset_t *set, sigset_t *oldset,
2891 if (sigsetsize != sizeof(compat_sigset_t))
2893 if (get_compat_sigset(set, usigmask))
2896 *oldset = current->blocked;
2897 set_current_blocked(set);
2901 EXPORT_SYMBOL(set_compat_user_sigmask);
2905 * restore_user_sigmask:
2906 * usigmask: sigmask passed in from userland.
2907 * sigsaved: saved sigmask when the syscall started and changed the sigmask to
2910 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2911 * epoll_pwait where a new sigmask is passed in from userland for the syscalls.
2913 void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved)
2919 * When signals are pending, do not restore them here.
2920 * Restoring sigmask here can lead to delivering signals that the above
2921 * syscalls are intended to block because of the sigmask passed in.
2923 if (signal_pending(current)) {
2924 current->saved_sigmask = *sigsaved;
2925 set_restore_sigmask();
2930 * This is needed because the fast syscall return path does not restore
2931 * saved_sigmask when signals are not pending.
2933 set_current_blocked(sigsaved);
2935 EXPORT_SYMBOL(restore_user_sigmask);
2938 * sys_rt_sigprocmask - change the list of currently blocked signals
2939 * @how: whether to add, remove, or set signals
2940 * @nset: stores pending signals
2941 * @oset: previous value of signal mask if non-null
2942 * @sigsetsize: size of sigset_t type
2944 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
2945 sigset_t __user *, oset, size_t, sigsetsize)
2947 sigset_t old_set, new_set;
2950 /* XXX: Don't preclude handling different sized sigset_t's. */
2951 if (sigsetsize != sizeof(sigset_t))
2954 old_set = current->blocked;
2957 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
2959 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2961 error = sigprocmask(how, &new_set, NULL);
2967 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
2974 #ifdef CONFIG_COMPAT
2975 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
2976 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
2978 sigset_t old_set = current->blocked;
2980 /* XXX: Don't preclude handling different sized sigset_t's. */
2981 if (sigsetsize != sizeof(sigset_t))
2987 if (get_compat_sigset(&new_set, nset))
2989 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
2991 error = sigprocmask(how, &new_set, NULL);
2995 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
2999 static void do_sigpending(sigset_t *set)
3001 spin_lock_irq(¤t->sighand->siglock);
3002 sigorsets(set, ¤t->pending.signal,
3003 ¤t->signal->shared_pending.signal);
3004 spin_unlock_irq(¤t->sighand->siglock);
3006 /* Outside the lock because only this thread touches it. */
3007 sigandsets(set, ¤t->blocked, set);
3011 * sys_rt_sigpending - examine a pending signal that has been raised
3013 * @uset: stores pending signals
3014 * @sigsetsize: size of sigset_t type or larger
3016 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3020 if (sigsetsize > sizeof(*uset))
3023 do_sigpending(&set);
3025 if (copy_to_user(uset, &set, sigsetsize))
3031 #ifdef CONFIG_COMPAT
3032 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3033 compat_size_t, sigsetsize)
3037 if (sigsetsize > sizeof(*uset))
3040 do_sigpending(&set);
3042 return put_compat_sigset(uset, &set, sigsetsize);
3046 static const struct {
3047 unsigned char limit, layout;
3049 [SIGILL] = { NSIGILL, SIL_FAULT },
3050 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3051 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3052 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3053 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3055 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3057 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3058 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3059 [SIGSYS] = { NSIGSYS, SIL_SYS },
3062 static bool known_siginfo_layout(unsigned sig, int si_code)
3064 if (si_code == SI_KERNEL)
3066 else if ((si_code > SI_USER)) {
3067 if (sig_specific_sicodes(sig)) {
3068 if (si_code <= sig_sicodes[sig].limit)
3071 else if (si_code <= NSIGPOLL)
3074 else if (si_code >= SI_DETHREAD)
3076 else if (si_code == SI_ASYNCNL)
3081 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3083 enum siginfo_layout layout = SIL_KILL;
3084 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3085 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3086 (si_code <= sig_sicodes[sig].limit)) {
3087 layout = sig_sicodes[sig].layout;
3088 /* Handle the exceptions */
3089 if ((sig == SIGBUS) &&
3090 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3091 layout = SIL_FAULT_MCEERR;
3092 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3093 layout = SIL_FAULT_BNDERR;
3095 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3096 layout = SIL_FAULT_PKUERR;
3099 else if (si_code <= NSIGPOLL)
3102 if (si_code == SI_TIMER)
3104 else if (si_code == SI_SIGIO)
3106 else if (si_code < 0)
3112 static inline char __user *si_expansion(const siginfo_t __user *info)
3114 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3117 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3119 char __user *expansion = si_expansion(to);
3120 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3122 if (clear_user(expansion, SI_EXPANSION_SIZE))
3127 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3128 const siginfo_t __user *from)
3130 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3131 char __user *expansion = si_expansion(from);
3132 char buf[SI_EXPANSION_SIZE];
3135 * An unknown si_code might need more than
3136 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3137 * extra bytes are 0. This guarantees copy_siginfo_to_user
3138 * will return this data to userspace exactly.
3140 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3142 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3150 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3151 const siginfo_t __user *from)
3153 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3155 to->si_signo = signo;
3156 return post_copy_siginfo_from_user(to, from);
3159 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3161 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3163 return post_copy_siginfo_from_user(to, from);
3166 #ifdef CONFIG_COMPAT
3167 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
3168 const struct kernel_siginfo *from)
3169 #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
3171 return __copy_siginfo_to_user32(to, from, in_x32_syscall());
3173 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3174 const struct kernel_siginfo *from, bool x32_ABI)
3177 struct compat_siginfo new;
3178 memset(&new, 0, sizeof(new));
3180 new.si_signo = from->si_signo;
3181 new.si_errno = from->si_errno;
3182 new.si_code = from->si_code;
3183 switch(siginfo_layout(from->si_signo, from->si_code)) {
3185 new.si_pid = from->si_pid;
3186 new.si_uid = from->si_uid;
3189 new.si_tid = from->si_tid;
3190 new.si_overrun = from->si_overrun;
3191 new.si_int = from->si_int;
3194 new.si_band = from->si_band;
3195 new.si_fd = from->si_fd;
3198 new.si_addr = ptr_to_compat(from->si_addr);
3199 #ifdef __ARCH_SI_TRAPNO
3200 new.si_trapno = from->si_trapno;
3203 case SIL_FAULT_MCEERR:
3204 new.si_addr = ptr_to_compat(from->si_addr);
3205 #ifdef __ARCH_SI_TRAPNO
3206 new.si_trapno = from->si_trapno;
3208 new.si_addr_lsb = from->si_addr_lsb;
3210 case SIL_FAULT_BNDERR:
3211 new.si_addr = ptr_to_compat(from->si_addr);
3212 #ifdef __ARCH_SI_TRAPNO
3213 new.si_trapno = from->si_trapno;
3215 new.si_lower = ptr_to_compat(from->si_lower);
3216 new.si_upper = ptr_to_compat(from->si_upper);
3218 case SIL_FAULT_PKUERR:
3219 new.si_addr = ptr_to_compat(from->si_addr);
3220 #ifdef __ARCH_SI_TRAPNO
3221 new.si_trapno = from->si_trapno;
3223 new.si_pkey = from->si_pkey;
3226 new.si_pid = from->si_pid;
3227 new.si_uid = from->si_uid;
3228 new.si_status = from->si_status;
3229 #ifdef CONFIG_X86_X32_ABI
3231 new._sifields._sigchld_x32._utime = from->si_utime;
3232 new._sifields._sigchld_x32._stime = from->si_stime;
3236 new.si_utime = from->si_utime;
3237 new.si_stime = from->si_stime;
3241 new.si_pid = from->si_pid;
3242 new.si_uid = from->si_uid;
3243 new.si_int = from->si_int;
3246 new.si_call_addr = ptr_to_compat(from->si_call_addr);
3247 new.si_syscall = from->si_syscall;
3248 new.si_arch = from->si_arch;
3252 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3258 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3259 const struct compat_siginfo *from)
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 = compat_ptr(from->si_addr);
3281 #ifdef __ARCH_SI_TRAPNO
3282 to->si_trapno = from->si_trapno;
3285 case SIL_FAULT_MCEERR:
3286 to->si_addr = compat_ptr(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 = compat_ptr(from->si_addr);
3294 #ifdef __ARCH_SI_TRAPNO
3295 to->si_trapno = from->si_trapno;
3297 to->si_lower = compat_ptr(from->si_lower);
3298 to->si_upper = compat_ptr(from->si_upper);
3300 case SIL_FAULT_PKUERR:
3301 to->si_addr = compat_ptr(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 #ifdef CONFIG_X86_X32_ABI
3312 if (in_x32_syscall()) {
3313 to->si_utime = from->_sifields._sigchld_x32._utime;
3314 to->si_stime = from->_sifields._sigchld_x32._stime;
3318 to->si_utime = from->si_utime;
3319 to->si_stime = from->si_stime;
3323 to->si_pid = from->si_pid;
3324 to->si_uid = from->si_uid;
3325 to->si_int = from->si_int;
3328 to->si_call_addr = compat_ptr(from->si_call_addr);
3329 to->si_syscall = from->si_syscall;
3330 to->si_arch = from->si_arch;
3336 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3337 const struct compat_siginfo __user *ufrom)
3339 struct compat_siginfo from;
3341 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3344 from.si_signo = signo;
3345 return post_copy_siginfo_from_user32(to, &from);
3348 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3349 const struct compat_siginfo __user *ufrom)
3351 struct compat_siginfo from;
3353 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3356 return post_copy_siginfo_from_user32(to, &from);
3358 #endif /* CONFIG_COMPAT */
3361 * do_sigtimedwait - wait for queued signals specified in @which
3362 * @which: queued signals to wait for
3363 * @info: if non-null, the signal's siginfo is returned here
3364 * @ts: upper bound on process time suspension
3366 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3367 const struct timespec64 *ts)
3369 ktime_t *to = NULL, timeout = KTIME_MAX;
3370 struct task_struct *tsk = current;
3371 sigset_t mask = *which;
3375 if (!timespec64_valid(ts))
3377 timeout = timespec64_to_ktime(*ts);
3382 * Invert the set of allowed signals to get those we want to block.
3384 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3387 spin_lock_irq(&tsk->sighand->siglock);
3388 sig = dequeue_signal(tsk, &mask, info);
3389 if (!sig && timeout) {
3391 * None ready, temporarily unblock those we're interested
3392 * while we are sleeping in so that we'll be awakened when
3393 * they arrive. Unblocking is always fine, we can avoid
3394 * set_current_blocked().
3396 tsk->real_blocked = tsk->blocked;
3397 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3398 recalc_sigpending();
3399 spin_unlock_irq(&tsk->sighand->siglock);
3401 __set_current_state(TASK_INTERRUPTIBLE);
3402 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3404 spin_lock_irq(&tsk->sighand->siglock);
3405 __set_task_blocked(tsk, &tsk->real_blocked);
3406 sigemptyset(&tsk->real_blocked);
3407 sig = dequeue_signal(tsk, &mask, info);
3409 spin_unlock_irq(&tsk->sighand->siglock);
3413 return ret ? -EINTR : -EAGAIN;
3417 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3419 * @uthese: queued signals to wait for
3420 * @uinfo: if non-null, the signal's siginfo is returned here
3421 * @uts: upper bound on process time suspension
3422 * @sigsetsize: size of sigset_t type
3424 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3425 siginfo_t __user *, uinfo,
3426 const struct __kernel_timespec __user *, uts,
3430 struct timespec64 ts;
3431 kernel_siginfo_t info;
3434 /* XXX: Don't preclude handling different sized sigset_t's. */
3435 if (sigsetsize != sizeof(sigset_t))
3438 if (copy_from_user(&these, uthese, sizeof(these)))
3442 if (get_timespec64(&ts, uts))
3446 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3448 if (ret > 0 && uinfo) {
3449 if (copy_siginfo_to_user(uinfo, &info))
3456 #ifdef CONFIG_COMPAT_32BIT_TIME
3457 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3458 siginfo_t __user *, uinfo,
3459 const struct old_timespec32 __user *, uts,
3463 struct timespec64 ts;
3464 kernel_siginfo_t info;
3467 if (sigsetsize != sizeof(sigset_t))
3470 if (copy_from_user(&these, uthese, sizeof(these)))
3474 if (get_old_timespec32(&ts, uts))
3478 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3480 if (ret > 0 && uinfo) {
3481 if (copy_siginfo_to_user(uinfo, &info))
3489 #ifdef CONFIG_COMPAT
3490 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3491 struct compat_siginfo __user *, uinfo,
3492 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3495 struct timespec64 t;
3496 kernel_siginfo_t info;
3499 if (sigsetsize != sizeof(sigset_t))
3502 if (get_compat_sigset(&s, uthese))
3506 if (get_timespec64(&t, uts))
3510 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3512 if (ret > 0 && uinfo) {
3513 if (copy_siginfo_to_user32(uinfo, &info))
3520 #ifdef CONFIG_COMPAT_32BIT_TIME
3521 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3522 struct compat_siginfo __user *, uinfo,
3523 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3526 struct timespec64 t;
3527 kernel_siginfo_t info;
3530 if (sigsetsize != sizeof(sigset_t))
3533 if (get_compat_sigset(&s, uthese))
3537 if (get_old_timespec32(&t, uts))
3541 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3543 if (ret > 0 && uinfo) {
3544 if (copy_siginfo_to_user32(uinfo, &info))
3553 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3555 clear_siginfo(info);
3556 info->si_signo = sig;
3558 info->si_code = SI_USER;
3559 info->si_pid = task_tgid_vnr(current);
3560 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3564 * sys_kill - send a signal to a process
3565 * @pid: the PID of the process
3566 * @sig: signal to be sent
3568 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3570 struct kernel_siginfo info;
3572 prepare_kill_siginfo(sig, &info);
3574 return kill_something_info(sig, &info, pid);
3578 * Verify that the signaler and signalee either are in the same pid namespace
3579 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3582 static bool access_pidfd_pidns(struct pid *pid)
3584 struct pid_namespace *active = task_active_pid_ns(current);
3585 struct pid_namespace *p = ns_of_pid(pid);
3598 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, siginfo_t *info)
3600 #ifdef CONFIG_COMPAT
3602 * Avoid hooking up compat syscalls and instead handle necessary
3603 * conversions here. Note, this is a stop-gap measure and should not be
3604 * considered a generic solution.
3606 if (in_compat_syscall())
3607 return copy_siginfo_from_user32(
3608 kinfo, (struct compat_siginfo __user *)info);
3610 return copy_siginfo_from_user(kinfo, info);
3613 static struct pid *pidfd_to_pid(const struct file *file)
3615 if (file->f_op == &pidfd_fops)
3616 return file->private_data;
3618 return tgid_pidfd_to_pid(file);
3622 * sys_pidfd_send_signal - send a signal to a process through a task file
3624 * @pidfd: the file descriptor of the process
3625 * @sig: signal to be sent
3626 * @info: the signal info
3627 * @flags: future flags to be passed
3629 * The syscall currently only signals via PIDTYPE_PID which covers
3630 * kill(<positive-pid>, <signal>. It does not signal threads or process
3632 * In order to extend the syscall to threads and process groups the @flags
3633 * argument should be used. In essence, the @flags argument will determine
3634 * what is signaled and not the file descriptor itself. Put in other words,
3635 * grouping is a property of the flags argument not a property of the file
3638 * Return: 0 on success, negative errno on failure
3640 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3641 siginfo_t __user *, info, unsigned int, flags)
3646 kernel_siginfo_t kinfo;
3648 /* Enforce flags be set to 0 until we add an extension. */
3656 /* Is this a pidfd? */
3657 pid = pidfd_to_pid(f.file);
3664 if (!access_pidfd_pidns(pid))
3668 ret = copy_siginfo_from_user_any(&kinfo, info);
3673 if (unlikely(sig != kinfo.si_signo))
3676 /* Only allow sending arbitrary signals to yourself. */
3678 if ((task_pid(current) != pid) &&
3679 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3682 prepare_kill_siginfo(sig, &kinfo);
3685 ret = kill_pid_info(sig, &kinfo, pid);
3693 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3695 struct task_struct *p;
3699 p = find_task_by_vpid(pid);
3700 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3701 error = check_kill_permission(sig, info, p);
3703 * The null signal is a permissions and process existence
3704 * probe. No signal is actually delivered.
3706 if (!error && sig) {
3707 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3709 * If lock_task_sighand() failed we pretend the task
3710 * dies after receiving the signal. The window is tiny,
3711 * and the signal is private anyway.
3713 if (unlikely(error == -ESRCH))
3722 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3724 struct kernel_siginfo info;
3726 clear_siginfo(&info);
3727 info.si_signo = sig;
3729 info.si_code = SI_TKILL;
3730 info.si_pid = task_tgid_vnr(current);
3731 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3733 return do_send_specific(tgid, pid, sig, &info);
3737 * sys_tgkill - send signal to one specific thread
3738 * @tgid: the thread group ID of the thread
3739 * @pid: the PID of the thread
3740 * @sig: signal to be sent
3742 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3743 * exists but it's not belonging to the target process anymore. This
3744 * method solves the problem of threads exiting and PIDs getting reused.
3746 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3748 /* This is only valid for single tasks */
3749 if (pid <= 0 || tgid <= 0)
3752 return do_tkill(tgid, pid, sig);
3756 * sys_tkill - send signal to one specific task
3757 * @pid: the PID of the task
3758 * @sig: signal to be sent
3760 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3762 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3764 /* This is only valid for single tasks */
3768 return do_tkill(0, pid, sig);
3771 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3773 /* Not even root can pretend to send signals from the kernel.
3774 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3776 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3777 (task_pid_vnr(current) != pid))
3780 /* POSIX.1b doesn't mention process groups. */
3781 return kill_proc_info(sig, info, pid);
3785 * sys_rt_sigqueueinfo - send signal information to a signal
3786 * @pid: the PID of the thread
3787 * @sig: signal to be sent
3788 * @uinfo: signal info to be sent
3790 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3791 siginfo_t __user *, uinfo)
3793 kernel_siginfo_t info;
3794 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3797 return do_rt_sigqueueinfo(pid, sig, &info);
3800 #ifdef CONFIG_COMPAT
3801 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3804 struct compat_siginfo __user *, uinfo)
3806 kernel_siginfo_t info;
3807 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3810 return do_rt_sigqueueinfo(pid, sig, &info);
3814 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
3816 /* This is only valid for single tasks */
3817 if (pid <= 0 || tgid <= 0)
3820 /* Not even root can pretend to send signals from the kernel.
3821 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3823 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3824 (task_pid_vnr(current) != pid))
3827 return do_send_specific(tgid, pid, sig, info);
3830 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3831 siginfo_t __user *, uinfo)
3833 kernel_siginfo_t info;
3834 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3837 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3840 #ifdef CONFIG_COMPAT
3841 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3845 struct compat_siginfo __user *, uinfo)
3847 kernel_siginfo_t info;
3848 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3851 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3856 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3858 void kernel_sigaction(int sig, __sighandler_t action)
3860 spin_lock_irq(¤t->sighand->siglock);
3861 current->sighand->action[sig - 1].sa.sa_handler = action;
3862 if (action == SIG_IGN) {
3866 sigaddset(&mask, sig);
3868 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3869 flush_sigqueue_mask(&mask, ¤t->pending);
3870 recalc_sigpending();
3872 spin_unlock_irq(¤t->sighand->siglock);
3874 EXPORT_SYMBOL(kernel_sigaction);
3876 void __weak sigaction_compat_abi(struct k_sigaction *act,
3877 struct k_sigaction *oact)
3881 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3883 struct task_struct *p = current, *t;
3884 struct k_sigaction *k;
3887 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3890 k = &p->sighand->action[sig-1];
3892 spin_lock_irq(&p->sighand->siglock);
3896 sigaction_compat_abi(act, oact);
3899 sigdelsetmask(&act->sa.sa_mask,
3900 sigmask(SIGKILL) | sigmask(SIGSTOP));
3904 * "Setting a signal action to SIG_IGN for a signal that is
3905 * pending shall cause the pending signal to be discarded,
3906 * whether or not it is blocked."
3908 * "Setting a signal action to SIG_DFL for a signal that is
3909 * pending and whose default action is to ignore the signal
3910 * (for example, SIGCHLD), shall cause the pending signal to
3911 * be discarded, whether or not it is blocked"
3913 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3915 sigaddset(&mask, sig);
3916 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3917 for_each_thread(p, t)
3918 flush_sigqueue_mask(&mask, &t->pending);
3922 spin_unlock_irq(&p->sighand->siglock);
3927 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
3930 struct task_struct *t = current;
3933 memset(oss, 0, sizeof(stack_t));
3934 oss->ss_sp = (void __user *) t->sas_ss_sp;
3935 oss->ss_size = t->sas_ss_size;
3936 oss->ss_flags = sas_ss_flags(sp) |
3937 (current->sas_ss_flags & SS_FLAG_BITS);
3941 void __user *ss_sp = ss->ss_sp;
3942 size_t ss_size = ss->ss_size;
3943 unsigned ss_flags = ss->ss_flags;
3946 if (unlikely(on_sig_stack(sp)))
3949 ss_mode = ss_flags & ~SS_FLAG_BITS;
3950 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
3954 if (ss_mode == SS_DISABLE) {
3958 if (unlikely(ss_size < min_ss_size))
3962 t->sas_ss_sp = (unsigned long) ss_sp;
3963 t->sas_ss_size = ss_size;
3964 t->sas_ss_flags = ss_flags;
3969 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
3973 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
3975 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
3976 current_user_stack_pointer(),
3978 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
3983 int restore_altstack(const stack_t __user *uss)
3986 if (copy_from_user(&new, uss, sizeof(stack_t)))
3988 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
3990 /* squash all but EFAULT for now */
3994 int __save_altstack(stack_t __user *uss, unsigned long sp)
3996 struct task_struct *t = current;
3997 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
3998 __put_user(t->sas_ss_flags, &uss->ss_flags) |
3999 __put_user(t->sas_ss_size, &uss->ss_size);
4002 if (t->sas_ss_flags & SS_AUTODISARM)
4007 #ifdef CONFIG_COMPAT
4008 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4009 compat_stack_t __user *uoss_ptr)
4015 compat_stack_t uss32;
4016 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4018 uss.ss_sp = compat_ptr(uss32.ss_sp);
4019 uss.ss_flags = uss32.ss_flags;
4020 uss.ss_size = uss32.ss_size;
4022 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4023 compat_user_stack_pointer(),
4024 COMPAT_MINSIGSTKSZ);
4025 if (ret >= 0 && uoss_ptr) {
4027 memset(&old, 0, sizeof(old));
4028 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4029 old.ss_flags = uoss.ss_flags;
4030 old.ss_size = uoss.ss_size;
4031 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4037 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4038 const compat_stack_t __user *, uss_ptr,
4039 compat_stack_t __user *, uoss_ptr)
4041 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4044 int compat_restore_altstack(const compat_stack_t __user *uss)
4046 int err = do_compat_sigaltstack(uss, NULL);
4047 /* squash all but -EFAULT for now */
4048 return err == -EFAULT ? err : 0;
4051 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4054 struct task_struct *t = current;
4055 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4057 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4058 __put_user(t->sas_ss_size, &uss->ss_size);
4061 if (t->sas_ss_flags & SS_AUTODISARM)
4067 #ifdef __ARCH_WANT_SYS_SIGPENDING
4070 * sys_sigpending - examine pending signals
4071 * @uset: where mask of pending signal is returned
4073 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4077 if (sizeof(old_sigset_t) > sizeof(*uset))
4080 do_sigpending(&set);
4082 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4088 #ifdef CONFIG_COMPAT
4089 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4093 do_sigpending(&set);
4095 return put_user(set.sig[0], set32);
4101 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4103 * sys_sigprocmask - examine and change blocked signals
4104 * @how: whether to add, remove, or set signals
4105 * @nset: signals to add or remove (if non-null)
4106 * @oset: previous value of signal mask if non-null
4108 * Some platforms have their own version with special arguments;
4109 * others support only sys_rt_sigprocmask.
4112 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4113 old_sigset_t __user *, oset)
4115 old_sigset_t old_set, new_set;
4116 sigset_t new_blocked;
4118 old_set = current->blocked.sig[0];
4121 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4124 new_blocked = current->blocked;
4128 sigaddsetmask(&new_blocked, new_set);
4131 sigdelsetmask(&new_blocked, new_set);
4134 new_blocked.sig[0] = new_set;
4140 set_current_blocked(&new_blocked);
4144 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4150 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4152 #ifndef CONFIG_ODD_RT_SIGACTION
4154 * sys_rt_sigaction - alter an action taken by a process
4155 * @sig: signal to be sent
4156 * @act: new sigaction
4157 * @oact: used to save the previous sigaction
4158 * @sigsetsize: size of sigset_t type
4160 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4161 const struct sigaction __user *, act,
4162 struct sigaction __user *, oact,
4165 struct k_sigaction new_sa, old_sa;
4168 /* XXX: Don't preclude handling different sized sigset_t's. */
4169 if (sigsetsize != sizeof(sigset_t))
4172 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4175 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4179 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4184 #ifdef CONFIG_COMPAT
4185 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4186 const struct compat_sigaction __user *, act,
4187 struct compat_sigaction __user *, oact,
4188 compat_size_t, sigsetsize)
4190 struct k_sigaction new_ka, old_ka;
4191 #ifdef __ARCH_HAS_SA_RESTORER
4192 compat_uptr_t restorer;
4196 /* XXX: Don't preclude handling different sized sigset_t's. */
4197 if (sigsetsize != sizeof(compat_sigset_t))
4201 compat_uptr_t handler;
4202 ret = get_user(handler, &act->sa_handler);
4203 new_ka.sa.sa_handler = compat_ptr(handler);
4204 #ifdef __ARCH_HAS_SA_RESTORER
4205 ret |= get_user(restorer, &act->sa_restorer);
4206 new_ka.sa.sa_restorer = compat_ptr(restorer);
4208 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4209 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4214 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4216 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4218 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4219 sizeof(oact->sa_mask));
4220 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4221 #ifdef __ARCH_HAS_SA_RESTORER
4222 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4223 &oact->sa_restorer);
4229 #endif /* !CONFIG_ODD_RT_SIGACTION */
4231 #ifdef CONFIG_OLD_SIGACTION
4232 SYSCALL_DEFINE3(sigaction, int, sig,
4233 const struct old_sigaction __user *, act,
4234 struct old_sigaction __user *, oact)
4236 struct k_sigaction new_ka, old_ka;
4241 if (!access_ok(act, sizeof(*act)) ||
4242 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4243 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4244 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4245 __get_user(mask, &act->sa_mask))
4247 #ifdef __ARCH_HAS_KA_RESTORER
4248 new_ka.ka_restorer = NULL;
4250 siginitset(&new_ka.sa.sa_mask, mask);
4253 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4256 if (!access_ok(oact, sizeof(*oact)) ||
4257 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4258 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4259 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4260 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4267 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4268 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4269 const struct compat_old_sigaction __user *, act,
4270 struct compat_old_sigaction __user *, oact)
4272 struct k_sigaction new_ka, old_ka;
4274 compat_old_sigset_t mask;
4275 compat_uptr_t handler, restorer;
4278 if (!access_ok(act, sizeof(*act)) ||
4279 __get_user(handler, &act->sa_handler) ||
4280 __get_user(restorer, &act->sa_restorer) ||
4281 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4282 __get_user(mask, &act->sa_mask))
4285 #ifdef __ARCH_HAS_KA_RESTORER
4286 new_ka.ka_restorer = NULL;
4288 new_ka.sa.sa_handler = compat_ptr(handler);
4289 new_ka.sa.sa_restorer = compat_ptr(restorer);
4290 siginitset(&new_ka.sa.sa_mask, mask);
4293 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4296 if (!access_ok(oact, sizeof(*oact)) ||
4297 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4298 &oact->sa_handler) ||
4299 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4300 &oact->sa_restorer) ||
4301 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4302 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4309 #ifdef CONFIG_SGETMASK_SYSCALL
4312 * For backwards compatibility. Functionality superseded by sigprocmask.
4314 SYSCALL_DEFINE0(sgetmask)
4317 return current->blocked.sig[0];
4320 SYSCALL_DEFINE1(ssetmask, int, newmask)
4322 int old = current->blocked.sig[0];
4325 siginitset(&newset, newmask);
4326 set_current_blocked(&newset);
4330 #endif /* CONFIG_SGETMASK_SYSCALL */
4332 #ifdef __ARCH_WANT_SYS_SIGNAL
4334 * For backwards compatibility. Functionality superseded by sigaction.
4336 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4338 struct k_sigaction new_sa, old_sa;
4341 new_sa.sa.sa_handler = handler;
4342 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4343 sigemptyset(&new_sa.sa.sa_mask);
4345 ret = do_sigaction(sig, &new_sa, &old_sa);
4347 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4349 #endif /* __ARCH_WANT_SYS_SIGNAL */
4351 #ifdef __ARCH_WANT_SYS_PAUSE
4353 SYSCALL_DEFINE0(pause)
4355 while (!signal_pending(current)) {
4356 __set_current_state(TASK_INTERRUPTIBLE);
4359 return -ERESTARTNOHAND;
4364 static int sigsuspend(sigset_t *set)
4366 current->saved_sigmask = current->blocked;
4367 set_current_blocked(set);
4369 while (!signal_pending(current)) {
4370 __set_current_state(TASK_INTERRUPTIBLE);
4373 set_restore_sigmask();
4374 return -ERESTARTNOHAND;
4378 * sys_rt_sigsuspend - replace the signal mask for a value with the
4379 * @unewset value until a signal is received
4380 * @unewset: new signal mask value
4381 * @sigsetsize: size of sigset_t type
4383 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4387 /* XXX: Don't preclude handling different sized sigset_t's. */
4388 if (sigsetsize != sizeof(sigset_t))
4391 if (copy_from_user(&newset, unewset, sizeof(newset)))
4393 return sigsuspend(&newset);
4396 #ifdef CONFIG_COMPAT
4397 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4401 /* XXX: Don't preclude handling different sized sigset_t's. */
4402 if (sigsetsize != sizeof(sigset_t))
4405 if (get_compat_sigset(&newset, unewset))
4407 return sigsuspend(&newset);
4411 #ifdef CONFIG_OLD_SIGSUSPEND
4412 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4415 siginitset(&blocked, mask);
4416 return sigsuspend(&blocked);
4419 #ifdef CONFIG_OLD_SIGSUSPEND3
4420 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4423 siginitset(&blocked, mask);
4424 return sigsuspend(&blocked);
4428 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4433 static inline void siginfo_buildtime_checks(void)
4435 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4437 /* Verify the offsets in the two siginfos match */
4438 #define CHECK_OFFSET(field) \
4439 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4442 CHECK_OFFSET(si_pid);
4443 CHECK_OFFSET(si_uid);
4446 CHECK_OFFSET(si_tid);
4447 CHECK_OFFSET(si_overrun);
4448 CHECK_OFFSET(si_value);
4451 CHECK_OFFSET(si_pid);
4452 CHECK_OFFSET(si_uid);
4453 CHECK_OFFSET(si_value);
4456 CHECK_OFFSET(si_pid);
4457 CHECK_OFFSET(si_uid);
4458 CHECK_OFFSET(si_status);
4459 CHECK_OFFSET(si_utime);
4460 CHECK_OFFSET(si_stime);
4463 CHECK_OFFSET(si_addr);
4464 CHECK_OFFSET(si_addr_lsb);
4465 CHECK_OFFSET(si_lower);
4466 CHECK_OFFSET(si_upper);
4467 CHECK_OFFSET(si_pkey);
4470 CHECK_OFFSET(si_band);
4471 CHECK_OFFSET(si_fd);
4474 CHECK_OFFSET(si_call_addr);
4475 CHECK_OFFSET(si_syscall);
4476 CHECK_OFFSET(si_arch);
4480 void __init signals_init(void)
4482 siginfo_buildtime_checks();
4484 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
4487 #ifdef CONFIG_KGDB_KDB
4488 #include <linux/kdb.h>
4490 * kdb_send_sig - Allows kdb to send signals without exposing
4491 * signal internals. This function checks if the required locks are
4492 * available before calling the main signal code, to avoid kdb
4495 void kdb_send_sig(struct task_struct *t, int sig)
4497 static struct task_struct *kdb_prev_t;
4499 if (!spin_trylock(&t->sighand->siglock)) {
4500 kdb_printf("Can't do kill command now.\n"
4501 "The sigmask lock is held somewhere else in "
4502 "kernel, try again later\n");
4505 new_t = kdb_prev_t != t;
4507 if (t->state != TASK_RUNNING && new_t) {
4508 spin_unlock(&t->sighand->siglock);
4509 kdb_printf("Process is not RUNNING, sending a signal from "
4510 "kdb risks deadlock\n"
4511 "on the run queue locks. "
4512 "The signal has _not_ been sent.\n"
4513 "Reissue the kill command if you want to risk "
4517 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4518 spin_unlock(&t->sighand->siglock);
4520 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4523 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4525 #endif /* CONFIG_KGDB_KDB */