1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
9 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
10 * Changes to use preallocated sigqueue structures
11 * to allow signals to be sent reliably.
14 #include <linux/slab.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/debug.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/sched/cputime.h>
23 #include <linux/file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/tty.h>
27 #include <linux/binfmts.h>
28 #include <linux/coredump.h>
29 #include <linux/security.h>
30 #include <linux/syscalls.h>
31 #include <linux/ptrace.h>
32 #include <linux/signal.h>
33 #include <linux/signalfd.h>
34 #include <linux/ratelimit.h>
35 #include <linux/tracehook.h>
36 #include <linux/capability.h>
37 #include <linux/freezer.h>
38 #include <linux/pid_namespace.h>
39 #include <linux/nsproxy.h>
40 #include <linux/user_namespace.h>
41 #include <linux/uprobes.h>
42 #include <linux/compat.h>
43 #include <linux/cn_proc.h>
44 #include <linux/compiler.h>
45 #include <linux/posix-timers.h>
46 #include <linux/livepatch.h>
47 #include <linux/cgroup.h>
48 #include <linux/audit.h>
50 #define CREATE_TRACE_POINTS
51 #include <trace/events/signal.h>
53 #include <asm/param.h>
54 #include <linux/uaccess.h>
55 #include <asm/unistd.h>
56 #include <asm/siginfo.h>
57 #include <asm/cacheflush.h>
60 * SLAB caches for signal bits.
63 static struct kmem_cache *sigqueue_cachep;
65 int print_fatal_signals __read_mostly;
67 static void __user *sig_handler(struct task_struct *t, int sig)
69 return t->sighand->action[sig - 1].sa.sa_handler;
72 static inline bool sig_handler_ignored(void __user *handler, int sig)
74 /* Is it explicitly or implicitly ignored? */
75 return handler == SIG_IGN ||
76 (handler == SIG_DFL && sig_kernel_ignore(sig));
79 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
83 handler = sig_handler(t, sig);
85 /* SIGKILL and SIGSTOP may not be sent to the global init */
86 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
89 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
90 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
93 /* Only allow kernel generated signals to this kthread */
94 if (unlikely((t->flags & PF_KTHREAD) &&
95 (handler == SIG_KTHREAD_KERNEL) && !force))
98 return sig_handler_ignored(handler, sig);
101 static bool sig_ignored(struct task_struct *t, int sig, bool force)
104 * Blocked signals are never ignored, since the
105 * signal handler may change by the time it is
108 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
112 * Tracers may want to know about even ignored signal unless it
113 * is SIGKILL which can't be reported anyway but can be ignored
114 * by SIGNAL_UNKILLABLE task.
116 if (t->ptrace && sig != SIGKILL)
119 return sig_task_ignored(t, sig, force);
123 * Re-calculate pending state from the set of locally pending
124 * signals, globally pending signals, and blocked signals.
126 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
131 switch (_NSIG_WORDS) {
133 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
134 ready |= signal->sig[i] &~ blocked->sig[i];
137 case 4: ready = signal->sig[3] &~ blocked->sig[3];
138 ready |= signal->sig[2] &~ blocked->sig[2];
139 ready |= signal->sig[1] &~ blocked->sig[1];
140 ready |= signal->sig[0] &~ blocked->sig[0];
143 case 2: ready = signal->sig[1] &~ blocked->sig[1];
144 ready |= signal->sig[0] &~ blocked->sig[0];
147 case 1: ready = signal->sig[0] &~ blocked->sig[0];
152 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
154 static bool recalc_sigpending_tsk(struct task_struct *t)
156 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
157 PENDING(&t->pending, &t->blocked) ||
158 PENDING(&t->signal->shared_pending, &t->blocked) ||
159 cgroup_task_frozen(t)) {
160 set_tsk_thread_flag(t, TIF_SIGPENDING);
165 * We must never clear the flag in another thread, or in current
166 * when it's possible the current syscall is returning -ERESTART*.
167 * So we don't clear it here, and only callers who know they should do.
173 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
174 * This is superfluous when called on current, the wakeup is a harmless no-op.
176 void recalc_sigpending_and_wake(struct task_struct *t)
178 if (recalc_sigpending_tsk(t))
179 signal_wake_up(t, 0);
182 void recalc_sigpending(void)
184 if (!recalc_sigpending_tsk(current) && !freezing(current) &&
185 !klp_patch_pending(current))
186 clear_thread_flag(TIF_SIGPENDING);
189 EXPORT_SYMBOL(recalc_sigpending);
191 void calculate_sigpending(void)
193 /* Have any signals or users of TIF_SIGPENDING been delayed
196 spin_lock_irq(¤t->sighand->siglock);
197 set_tsk_thread_flag(current, TIF_SIGPENDING);
199 spin_unlock_irq(¤t->sighand->siglock);
202 /* Given the mask, find the first available signal that should be serviced. */
204 #define SYNCHRONOUS_MASK \
205 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
206 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
208 int next_signal(struct sigpending *pending, sigset_t *mask)
210 unsigned long i, *s, *m, x;
213 s = pending->signal.sig;
217 * Handle the first word specially: it contains the
218 * synchronous signals that need to be dequeued first.
222 if (x & SYNCHRONOUS_MASK)
223 x &= SYNCHRONOUS_MASK;
228 switch (_NSIG_WORDS) {
230 for (i = 1; i < _NSIG_WORDS; ++i) {
234 sig = ffz(~x) + i*_NSIG_BPW + 1;
243 sig = ffz(~x) + _NSIG_BPW + 1;
254 static inline void print_dropped_signal(int sig)
256 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
258 if (!print_fatal_signals)
261 if (!__ratelimit(&ratelimit_state))
264 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
265 current->comm, current->pid, sig);
269 * task_set_jobctl_pending - set jobctl pending bits
271 * @mask: pending bits to set
273 * Clear @mask from @task->jobctl. @mask must be subset of
274 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
275 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
276 * cleared. If @task is already being killed or exiting, this function
280 * Must be called with @task->sighand->siglock held.
283 * %true if @mask is set, %false if made noop because @task was dying.
285 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
287 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
288 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
289 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
291 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
294 if (mask & JOBCTL_STOP_SIGMASK)
295 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
297 task->jobctl |= mask;
302 * task_clear_jobctl_trapping - clear jobctl trapping bit
305 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
306 * Clear it and wake up the ptracer. Note that we don't need any further
307 * locking. @task->siglock guarantees that @task->parent points to the
311 * Must be called with @task->sighand->siglock held.
313 void task_clear_jobctl_trapping(struct task_struct *task)
315 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
316 task->jobctl &= ~JOBCTL_TRAPPING;
317 smp_mb(); /* advised by wake_up_bit() */
318 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
323 * task_clear_jobctl_pending - clear jobctl pending bits
325 * @mask: pending bits to clear
327 * Clear @mask from @task->jobctl. @mask must be subset of
328 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
329 * STOP bits are cleared together.
331 * If clearing of @mask leaves no stop or trap pending, this function calls
332 * task_clear_jobctl_trapping().
335 * Must be called with @task->sighand->siglock held.
337 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
339 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
341 if (mask & JOBCTL_STOP_PENDING)
342 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
344 task->jobctl &= ~mask;
346 if (!(task->jobctl & JOBCTL_PENDING_MASK))
347 task_clear_jobctl_trapping(task);
351 * task_participate_group_stop - participate in a group stop
352 * @task: task participating in a group stop
354 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
355 * Group stop states are cleared and the group stop count is consumed if
356 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
357 * stop, the appropriate `SIGNAL_*` flags are set.
360 * Must be called with @task->sighand->siglock held.
363 * %true if group stop completion should be notified to the parent, %false
366 static bool task_participate_group_stop(struct task_struct *task)
368 struct signal_struct *sig = task->signal;
369 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
371 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
373 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
378 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
379 sig->group_stop_count--;
382 * Tell the caller to notify completion iff we are entering into a
383 * fresh group stop. Read comment in do_signal_stop() for details.
385 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
386 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
392 void task_join_group_stop(struct task_struct *task)
394 /* Have the new thread join an on-going signal group stop */
395 unsigned long jobctl = current->jobctl;
396 if (jobctl & JOBCTL_STOP_PENDING) {
397 struct signal_struct *sig = current->signal;
398 unsigned long signr = jobctl & JOBCTL_STOP_SIGMASK;
399 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
400 if (task_set_jobctl_pending(task, signr | gstop)) {
401 sig->group_stop_count++;
407 * allocate a new signal queue record
408 * - this may be called without locks if and only if t == current, otherwise an
409 * appropriate lock must be held to stop the target task from exiting
411 static struct sigqueue *
412 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
414 struct sigqueue *q = NULL;
415 struct user_struct *user;
419 * Protect access to @t credentials. This can go away when all
420 * callers hold rcu read lock.
422 * NOTE! A pending signal will hold on to the user refcount,
423 * and we get/put the refcount only when the sigpending count
424 * changes from/to zero.
427 user = __task_cred(t)->user;
428 sigpending = atomic_inc_return(&user->sigpending);
433 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
434 q = kmem_cache_alloc(sigqueue_cachep, flags);
436 print_dropped_signal(sig);
439 if (unlikely(q == NULL)) {
440 if (atomic_dec_and_test(&user->sigpending))
443 INIT_LIST_HEAD(&q->list);
451 static void __sigqueue_free(struct sigqueue *q)
453 if (q->flags & SIGQUEUE_PREALLOC)
455 if (atomic_dec_and_test(&q->user->sigpending))
457 kmem_cache_free(sigqueue_cachep, q);
460 void flush_sigqueue(struct sigpending *queue)
464 sigemptyset(&queue->signal);
465 while (!list_empty(&queue->list)) {
466 q = list_entry(queue->list.next, struct sigqueue , list);
467 list_del_init(&q->list);
473 * Flush all pending signals for this kthread.
475 void flush_signals(struct task_struct *t)
479 spin_lock_irqsave(&t->sighand->siglock, flags);
480 clear_tsk_thread_flag(t, TIF_SIGPENDING);
481 flush_sigqueue(&t->pending);
482 flush_sigqueue(&t->signal->shared_pending);
483 spin_unlock_irqrestore(&t->sighand->siglock, flags);
485 EXPORT_SYMBOL(flush_signals);
487 #ifdef CONFIG_POSIX_TIMERS
488 static void __flush_itimer_signals(struct sigpending *pending)
490 sigset_t signal, retain;
491 struct sigqueue *q, *n;
493 signal = pending->signal;
494 sigemptyset(&retain);
496 list_for_each_entry_safe(q, n, &pending->list, list) {
497 int sig = q->info.si_signo;
499 if (likely(q->info.si_code != SI_TIMER)) {
500 sigaddset(&retain, sig);
502 sigdelset(&signal, sig);
503 list_del_init(&q->list);
508 sigorsets(&pending->signal, &signal, &retain);
511 void flush_itimer_signals(void)
513 struct task_struct *tsk = current;
516 spin_lock_irqsave(&tsk->sighand->siglock, flags);
517 __flush_itimer_signals(&tsk->pending);
518 __flush_itimer_signals(&tsk->signal->shared_pending);
519 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
523 void ignore_signals(struct task_struct *t)
527 for (i = 0; i < _NSIG; ++i)
528 t->sighand->action[i].sa.sa_handler = SIG_IGN;
534 * Flush all handlers for a task.
538 flush_signal_handlers(struct task_struct *t, int force_default)
541 struct k_sigaction *ka = &t->sighand->action[0];
542 for (i = _NSIG ; i != 0 ; i--) {
543 if (force_default || ka->sa.sa_handler != SIG_IGN)
544 ka->sa.sa_handler = SIG_DFL;
546 #ifdef __ARCH_HAS_SA_RESTORER
547 ka->sa.sa_restorer = NULL;
549 sigemptyset(&ka->sa.sa_mask);
554 bool unhandled_signal(struct task_struct *tsk, int sig)
556 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
557 if (is_global_init(tsk))
560 if (handler != SIG_IGN && handler != SIG_DFL)
563 /* if ptraced, let the tracer determine */
567 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
570 struct sigqueue *q, *first = NULL;
573 * Collect the siginfo appropriate to this signal. Check if
574 * there is another siginfo for the same signal.
576 list_for_each_entry(q, &list->list, list) {
577 if (q->info.si_signo == sig) {
584 sigdelset(&list->signal, sig);
588 list_del_init(&first->list);
589 copy_siginfo(info, &first->info);
592 (first->flags & SIGQUEUE_PREALLOC) &&
593 (info->si_code == SI_TIMER) &&
594 (info->si_sys_private);
596 __sigqueue_free(first);
599 * Ok, it wasn't in the queue. This must be
600 * a fast-pathed signal or we must have been
601 * out of queue space. So zero out the info.
604 info->si_signo = sig;
606 info->si_code = SI_USER;
612 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
613 kernel_siginfo_t *info, bool *resched_timer)
615 int sig = next_signal(pending, mask);
618 collect_signal(sig, pending, info, resched_timer);
623 * Dequeue a signal and return the element to the caller, which is
624 * expected to free it.
626 * All callers have to hold the siglock.
628 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
630 bool resched_timer = false;
633 /* We only dequeue private signals from ourselves, we don't let
634 * signalfd steal them
636 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
638 signr = __dequeue_signal(&tsk->signal->shared_pending,
639 mask, info, &resched_timer);
640 #ifdef CONFIG_POSIX_TIMERS
644 * itimers are process shared and we restart periodic
645 * itimers in the signal delivery path to prevent DoS
646 * attacks in the high resolution timer case. This is
647 * compliant with the old way of self-restarting
648 * itimers, as the SIGALRM is a legacy signal and only
649 * queued once. Changing the restart behaviour to
650 * restart the timer in the signal dequeue path is
651 * reducing the timer noise on heavy loaded !highres
654 if (unlikely(signr == SIGALRM)) {
655 struct hrtimer *tmr = &tsk->signal->real_timer;
657 if (!hrtimer_is_queued(tmr) &&
658 tsk->signal->it_real_incr != 0) {
659 hrtimer_forward(tmr, tmr->base->get_time(),
660 tsk->signal->it_real_incr);
661 hrtimer_restart(tmr);
671 if (unlikely(sig_kernel_stop(signr))) {
673 * Set a marker that we have dequeued a stop signal. Our
674 * caller might release the siglock and then the pending
675 * stop signal it is about to process is no longer in the
676 * pending bitmasks, but must still be cleared by a SIGCONT
677 * (and overruled by a SIGKILL). So those cases clear this
678 * shared flag after we've set it. Note that this flag may
679 * remain set after the signal we return is ignored or
680 * handled. That doesn't matter because its only purpose
681 * is to alert stop-signal processing code when another
682 * processor has come along and cleared the flag.
684 current->jobctl |= JOBCTL_STOP_DEQUEUED;
686 #ifdef CONFIG_POSIX_TIMERS
689 * Release the siglock to ensure proper locking order
690 * of timer locks outside of siglocks. Note, we leave
691 * irqs disabled here, since the posix-timers code is
692 * about to disable them again anyway.
694 spin_unlock(&tsk->sighand->siglock);
695 posixtimer_rearm(info);
696 spin_lock(&tsk->sighand->siglock);
698 /* Don't expose the si_sys_private value to userspace */
699 info->si_sys_private = 0;
704 EXPORT_SYMBOL_GPL(dequeue_signal);
706 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
708 struct task_struct *tsk = current;
709 struct sigpending *pending = &tsk->pending;
710 struct sigqueue *q, *sync = NULL;
713 * Might a synchronous signal be in the queue?
715 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
719 * Return the first synchronous signal in the queue.
721 list_for_each_entry(q, &pending->list, list) {
722 /* Synchronous signals have a postive si_code */
723 if ((q->info.si_code > SI_USER) &&
724 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
732 * Check if there is another siginfo for the same signal.
734 list_for_each_entry_continue(q, &pending->list, list) {
735 if (q->info.si_signo == sync->info.si_signo)
739 sigdelset(&pending->signal, sync->info.si_signo);
742 list_del_init(&sync->list);
743 copy_siginfo(info, &sync->info);
744 __sigqueue_free(sync);
745 return info->si_signo;
749 * Tell a process that it has a new active signal..
751 * NOTE! we rely on the previous spin_lock to
752 * lock interrupts for us! We can only be called with
753 * "siglock" held, and the local interrupt must
754 * have been disabled when that got acquired!
756 * No need to set need_resched since signal event passing
757 * goes through ->blocked
759 void signal_wake_up_state(struct task_struct *t, unsigned int state)
761 set_tsk_thread_flag(t, TIF_SIGPENDING);
763 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
764 * case. We don't check t->state here because there is a race with it
765 * executing another processor and just now entering stopped state.
766 * By using wake_up_state, we ensure the process will wake up and
767 * handle its death signal.
769 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
774 * Remove signals in mask from the pending set and queue.
775 * Returns 1 if any signals were found.
777 * All callers must be holding the siglock.
779 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
781 struct sigqueue *q, *n;
784 sigandsets(&m, mask, &s->signal);
785 if (sigisemptyset(&m))
788 sigandnsets(&s->signal, &s->signal, mask);
789 list_for_each_entry_safe(q, n, &s->list, list) {
790 if (sigismember(mask, q->info.si_signo)) {
791 list_del_init(&q->list);
797 static inline int is_si_special(const struct kernel_siginfo *info)
799 return info <= SEND_SIG_PRIV;
802 static inline bool si_fromuser(const struct kernel_siginfo *info)
804 return info == SEND_SIG_NOINFO ||
805 (!is_si_special(info) && SI_FROMUSER(info));
809 * called with RCU read lock from check_kill_permission()
811 static bool kill_ok_by_cred(struct task_struct *t)
813 const struct cred *cred = current_cred();
814 const struct cred *tcred = __task_cred(t);
816 return uid_eq(cred->euid, tcred->suid) ||
817 uid_eq(cred->euid, tcred->uid) ||
818 uid_eq(cred->uid, tcred->suid) ||
819 uid_eq(cred->uid, tcred->uid) ||
820 ns_capable(tcred->user_ns, CAP_KILL);
824 * Bad permissions for sending the signal
825 * - the caller must hold the RCU read lock
827 static int check_kill_permission(int sig, struct kernel_siginfo *info,
828 struct task_struct *t)
833 if (!valid_signal(sig))
836 if (!si_fromuser(info))
839 error = audit_signal_info(sig, t); /* Let audit system see the signal */
843 if (!same_thread_group(current, t) &&
844 !kill_ok_by_cred(t)) {
847 sid = task_session(t);
849 * We don't return the error if sid == NULL. The
850 * task was unhashed, the caller must notice this.
852 if (!sid || sid == task_session(current))
860 return security_task_kill(t, info, sig, NULL);
864 * ptrace_trap_notify - schedule trap to notify ptracer
865 * @t: tracee wanting to notify tracer
867 * This function schedules sticky ptrace trap which is cleared on the next
868 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
871 * If @t is running, STOP trap will be taken. If trapped for STOP and
872 * ptracer is listening for events, tracee is woken up so that it can
873 * re-trap for the new event. If trapped otherwise, STOP trap will be
874 * eventually taken without returning to userland after the existing traps
875 * are finished by PTRACE_CONT.
878 * Must be called with @task->sighand->siglock held.
880 static void ptrace_trap_notify(struct task_struct *t)
882 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
883 assert_spin_locked(&t->sighand->siglock);
885 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
886 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
890 * Handle magic process-wide effects of stop/continue signals. Unlike
891 * the signal actions, these happen immediately at signal-generation
892 * time regardless of blocking, ignoring, or handling. This does the
893 * actual continuing for SIGCONT, but not the actual stopping for stop
894 * signals. The process stop is done as a signal action for SIG_DFL.
896 * Returns true if the signal should be actually delivered, otherwise
897 * it should be dropped.
899 static bool prepare_signal(int sig, struct task_struct *p, bool force)
901 struct signal_struct *signal = p->signal;
902 struct task_struct *t;
905 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
906 if (!(signal->flags & SIGNAL_GROUP_EXIT))
907 return sig == SIGKILL;
909 * The process is in the middle of dying, nothing to do.
911 } else if (sig_kernel_stop(sig)) {
913 * This is a stop signal. Remove SIGCONT from all queues.
915 siginitset(&flush, sigmask(SIGCONT));
916 flush_sigqueue_mask(&flush, &signal->shared_pending);
917 for_each_thread(p, t)
918 flush_sigqueue_mask(&flush, &t->pending);
919 } else if (sig == SIGCONT) {
922 * Remove all stop signals from all queues, wake all threads.
924 siginitset(&flush, SIG_KERNEL_STOP_MASK);
925 flush_sigqueue_mask(&flush, &signal->shared_pending);
926 for_each_thread(p, t) {
927 flush_sigqueue_mask(&flush, &t->pending);
928 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
929 if (likely(!(t->ptrace & PT_SEIZED)))
930 wake_up_state(t, __TASK_STOPPED);
932 ptrace_trap_notify(t);
936 * Notify the parent with CLD_CONTINUED if we were stopped.
938 * If we were in the middle of a group stop, we pretend it
939 * was already finished, and then continued. Since SIGCHLD
940 * doesn't queue we report only CLD_STOPPED, as if the next
941 * CLD_CONTINUED was dropped.
944 if (signal->flags & SIGNAL_STOP_STOPPED)
945 why |= SIGNAL_CLD_CONTINUED;
946 else if (signal->group_stop_count)
947 why |= SIGNAL_CLD_STOPPED;
951 * The first thread which returns from do_signal_stop()
952 * will take ->siglock, notice SIGNAL_CLD_MASK, and
953 * notify its parent. See get_signal().
955 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
956 signal->group_stop_count = 0;
957 signal->group_exit_code = 0;
961 return !sig_ignored(p, sig, force);
965 * Test if P wants to take SIG. After we've checked all threads with this,
966 * it's equivalent to finding no threads not blocking SIG. Any threads not
967 * blocking SIG were ruled out because they are not running and already
968 * have pending signals. Such threads will dequeue from the shared queue
969 * as soon as they're available, so putting the signal on the shared queue
970 * will be equivalent to sending it to one such thread.
972 static inline bool wants_signal(int sig, struct task_struct *p)
974 if (sigismember(&p->blocked, sig))
977 if (p->flags & PF_EXITING)
983 if (task_is_stopped_or_traced(p))
986 return task_curr(p) || !signal_pending(p);
989 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
991 struct signal_struct *signal = p->signal;
992 struct task_struct *t;
995 * Now find a thread we can wake up to take the signal off the queue.
997 * If the main thread wants the signal, it gets first crack.
998 * Probably the least surprising to the average bear.
1000 if (wants_signal(sig, p))
1002 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1004 * There is just one thread and it does not need to be woken.
1005 * It will dequeue unblocked signals before it runs again.
1010 * Otherwise try to find a suitable thread.
1012 t = signal->curr_target;
1013 while (!wants_signal(sig, t)) {
1015 if (t == signal->curr_target)
1017 * No thread needs to be woken.
1018 * Any eligible threads will see
1019 * the signal in the queue soon.
1023 signal->curr_target = t;
1027 * Found a killable thread. If the signal will be fatal,
1028 * then start taking the whole group down immediately.
1030 if (sig_fatal(p, sig) &&
1031 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1032 !sigismember(&t->real_blocked, sig) &&
1033 (sig == SIGKILL || !p->ptrace)) {
1035 * This signal will be fatal to the whole group.
1037 if (!sig_kernel_coredump(sig)) {
1039 * Start a group exit and wake everybody up.
1040 * This way we don't have other threads
1041 * running and doing things after a slower
1042 * thread has the fatal signal pending.
1044 signal->flags = SIGNAL_GROUP_EXIT;
1045 signal->group_exit_code = sig;
1046 signal->group_stop_count = 0;
1049 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1050 sigaddset(&t->pending.signal, SIGKILL);
1051 signal_wake_up(t, 1);
1052 } while_each_thread(p, t);
1058 * The signal is already in the shared-pending queue.
1059 * Tell the chosen thread to wake up and dequeue it.
1061 signal_wake_up(t, sig == SIGKILL);
1065 static inline bool legacy_queue(struct sigpending *signals, int sig)
1067 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1070 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1071 enum pid_type type, bool force)
1073 struct sigpending *pending;
1075 int override_rlimit;
1076 int ret = 0, result;
1078 assert_spin_locked(&t->sighand->siglock);
1080 result = TRACE_SIGNAL_IGNORED;
1081 if (!prepare_signal(sig, t, force))
1084 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1086 * Short-circuit ignored signals and support queuing
1087 * exactly one non-rt signal, so that we can get more
1088 * detailed information about the cause of the signal.
1090 result = TRACE_SIGNAL_ALREADY_PENDING;
1091 if (legacy_queue(pending, sig))
1094 result = TRACE_SIGNAL_DELIVERED;
1096 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1098 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1102 * Real-time signals must be queued if sent by sigqueue, or
1103 * some other real-time mechanism. It is implementation
1104 * defined whether kill() does so. We attempt to do so, on
1105 * the principle of least surprise, but since kill is not
1106 * allowed to fail with EAGAIN when low on memory we just
1107 * make sure at least one signal gets delivered and don't
1108 * pass on the info struct.
1111 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1113 override_rlimit = 0;
1115 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
1117 list_add_tail(&q->list, &pending->list);
1118 switch ((unsigned long) info) {
1119 case (unsigned long) SEND_SIG_NOINFO:
1120 clear_siginfo(&q->info);
1121 q->info.si_signo = sig;
1122 q->info.si_errno = 0;
1123 q->info.si_code = SI_USER;
1124 q->info.si_pid = task_tgid_nr_ns(current,
1125 task_active_pid_ns(t));
1128 from_kuid_munged(task_cred_xxx(t, user_ns),
1132 case (unsigned long) SEND_SIG_PRIV:
1133 clear_siginfo(&q->info);
1134 q->info.si_signo = sig;
1135 q->info.si_errno = 0;
1136 q->info.si_code = SI_KERNEL;
1141 copy_siginfo(&q->info, info);
1144 } else if (!is_si_special(info) &&
1145 sig >= SIGRTMIN && info->si_code != SI_USER) {
1147 * Queue overflow, abort. We may abort if the
1148 * signal was rt and sent by user using something
1149 * other than kill().
1151 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1156 * This is a silent loss of information. We still
1157 * send the signal, but the *info bits are lost.
1159 result = TRACE_SIGNAL_LOSE_INFO;
1163 signalfd_notify(t, sig);
1164 sigaddset(&pending->signal, sig);
1166 /* Let multiprocess signals appear after on-going forks */
1167 if (type > PIDTYPE_TGID) {
1168 struct multiprocess_signals *delayed;
1169 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1170 sigset_t *signal = &delayed->signal;
1171 /* Can't queue both a stop and a continue signal */
1173 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1174 else if (sig_kernel_stop(sig))
1175 sigdelset(signal, SIGCONT);
1176 sigaddset(signal, sig);
1180 complete_signal(sig, t, type);
1182 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1186 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1189 switch (siginfo_layout(info->si_signo, info->si_code)) {
1198 case SIL_FAULT_MCEERR:
1199 case SIL_FAULT_BNDERR:
1200 case SIL_FAULT_PKUERR:
1208 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1211 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1214 if (info == SEND_SIG_NOINFO) {
1215 /* Force if sent from an ancestor pid namespace */
1216 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1217 } else if (info == SEND_SIG_PRIV) {
1218 /* Don't ignore kernel generated signals */
1220 } else if (has_si_pid_and_uid(info)) {
1221 /* SIGKILL and SIGSTOP is special or has ids */
1222 struct user_namespace *t_user_ns;
1225 t_user_ns = task_cred_xxx(t, user_ns);
1226 if (current_user_ns() != t_user_ns) {
1227 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1228 info->si_uid = from_kuid_munged(t_user_ns, uid);
1232 /* A kernel generated signal? */
1233 force = (info->si_code == SI_KERNEL);
1235 /* From an ancestor pid namespace? */
1236 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1241 return __send_signal(sig, info, t, type, force);
1244 static void print_fatal_signal(int signr)
1246 struct pt_regs *regs = signal_pt_regs();
1247 pr_info("potentially unexpected fatal signal %d.\n", signr);
1249 #if defined(__i386__) && !defined(__arch_um__)
1250 pr_info("code at %08lx: ", regs->ip);
1253 for (i = 0; i < 16; i++) {
1256 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1258 pr_cont("%02x ", insn);
1268 static int __init setup_print_fatal_signals(char *str)
1270 get_option (&str, &print_fatal_signals);
1275 __setup("print-fatal-signals=", setup_print_fatal_signals);
1278 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1280 return send_signal(sig, info, p, PIDTYPE_TGID);
1283 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1286 unsigned long flags;
1289 if (lock_task_sighand(p, &flags)) {
1290 ret = send_signal(sig, info, p, type);
1291 unlock_task_sighand(p, &flags);
1298 * Force a signal that the process can't ignore: if necessary
1299 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1301 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1302 * since we do not want to have a signal handler that was blocked
1303 * be invoked when user space had explicitly blocked it.
1305 * We don't want to have recursive SIGSEGV's etc, for example,
1306 * that is why we also clear SIGNAL_UNKILLABLE.
1309 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t)
1311 unsigned long int flags;
1312 int ret, blocked, ignored;
1313 struct k_sigaction *action;
1314 int sig = info->si_signo;
1316 spin_lock_irqsave(&t->sighand->siglock, flags);
1317 action = &t->sighand->action[sig-1];
1318 ignored = action->sa.sa_handler == SIG_IGN;
1319 blocked = sigismember(&t->blocked, sig);
1320 if (blocked || ignored) {
1321 action->sa.sa_handler = SIG_DFL;
1323 sigdelset(&t->blocked, sig);
1324 recalc_sigpending_and_wake(t);
1328 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1329 * debugging to leave init killable.
1331 if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
1332 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1333 ret = send_signal(sig, info, t, PIDTYPE_PID);
1334 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1339 int force_sig_info(struct kernel_siginfo *info)
1341 return force_sig_info_to_task(info, current);
1345 * Nuke all other threads in the group.
1347 int zap_other_threads(struct task_struct *p)
1349 struct task_struct *t = p;
1352 p->signal->group_stop_count = 0;
1354 while_each_thread(p, t) {
1355 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1358 /* Don't bother with already dead threads */
1361 sigaddset(&t->pending.signal, SIGKILL);
1362 signal_wake_up(t, 1);
1368 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1369 unsigned long *flags)
1371 struct sighand_struct *sighand;
1375 sighand = rcu_dereference(tsk->sighand);
1376 if (unlikely(sighand == NULL))
1380 * This sighand can be already freed and even reused, but
1381 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1382 * initializes ->siglock: this slab can't go away, it has
1383 * the same object type, ->siglock can't be reinitialized.
1385 * We need to ensure that tsk->sighand is still the same
1386 * after we take the lock, we can race with de_thread() or
1387 * __exit_signal(). In the latter case the next iteration
1388 * must see ->sighand == NULL.
1390 spin_lock_irqsave(&sighand->siglock, *flags);
1391 if (likely(sighand == tsk->sighand))
1393 spin_unlock_irqrestore(&sighand->siglock, *flags);
1401 * send signal info to all the members of a group
1403 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1404 struct task_struct *p, enum pid_type type)
1409 ret = check_kill_permission(sig, info, p);
1413 ret = do_send_sig_info(sig, info, p, type);
1419 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1420 * control characters do (^C, ^Z etc)
1421 * - the caller must hold at least a readlock on tasklist_lock
1423 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1425 struct task_struct *p = NULL;
1426 int retval, success;
1430 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1431 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1434 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1435 return success ? 0 : retval;
1438 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1441 struct task_struct *p;
1445 p = pid_task(pid, PIDTYPE_PID);
1447 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1449 if (likely(!p || error != -ESRCH))
1453 * The task was unhashed in between, try again. If it
1454 * is dead, pid_task() will return NULL, if we race with
1455 * de_thread() it will find the new leader.
1460 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1464 error = kill_pid_info(sig, info, find_vpid(pid));
1469 static inline bool kill_as_cred_perm(const struct cred *cred,
1470 struct task_struct *target)
1472 const struct cred *pcred = __task_cred(target);
1474 return uid_eq(cred->euid, pcred->suid) ||
1475 uid_eq(cred->euid, pcred->uid) ||
1476 uid_eq(cred->uid, pcred->suid) ||
1477 uid_eq(cred->uid, pcred->uid);
1481 * The usb asyncio usage of siginfo is wrong. The glibc support
1482 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1483 * AKA after the generic fields:
1484 * kernel_pid_t si_pid;
1485 * kernel_uid32_t si_uid;
1486 * sigval_t si_value;
1488 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1489 * after the generic fields is:
1490 * void __user *si_addr;
1492 * This is a practical problem when there is a 64bit big endian kernel
1493 * and a 32bit userspace. As the 32bit address will encoded in the low
1494 * 32bits of the pointer. Those low 32bits will be stored at higher
1495 * address than appear in a 32 bit pointer. So userspace will not
1496 * see the address it was expecting for it's completions.
1498 * There is nothing in the encoding that can allow
1499 * copy_siginfo_to_user32 to detect this confusion of formats, so
1500 * handle this by requiring the caller of kill_pid_usb_asyncio to
1501 * notice when this situration takes place and to store the 32bit
1502 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1505 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1506 struct pid *pid, const struct cred *cred)
1508 struct kernel_siginfo info;
1509 struct task_struct *p;
1510 unsigned long flags;
1513 if (!valid_signal(sig))
1516 clear_siginfo(&info);
1517 info.si_signo = sig;
1518 info.si_errno = errno;
1519 info.si_code = SI_ASYNCIO;
1520 *((sigval_t *)&info.si_pid) = addr;
1523 p = pid_task(pid, PIDTYPE_PID);
1528 if (!kill_as_cred_perm(cred, p)) {
1532 ret = security_task_kill(p, &info, sig, cred);
1537 if (lock_task_sighand(p, &flags)) {
1538 ret = __send_signal(sig, &info, p, PIDTYPE_TGID, false);
1539 unlock_task_sighand(p, &flags);
1547 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1550 * kill_something_info() interprets pid in interesting ways just like kill(2).
1552 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1553 * is probably wrong. Should make it like BSD or SYSV.
1556 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1562 ret = kill_pid_info(sig, info, find_vpid(pid));
1567 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1571 read_lock(&tasklist_lock);
1573 ret = __kill_pgrp_info(sig, info,
1574 pid ? find_vpid(-pid) : task_pgrp(current));
1576 int retval = 0, count = 0;
1577 struct task_struct * p;
1579 for_each_process(p) {
1580 if (task_pid_vnr(p) > 1 &&
1581 !same_thread_group(p, current)) {
1582 int err = group_send_sig_info(sig, info, p,
1589 ret = count ? retval : -ESRCH;
1591 read_unlock(&tasklist_lock);
1597 * These are for backward compatibility with the rest of the kernel source.
1600 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1603 * Make sure legacy kernel users don't send in bad values
1604 * (normal paths check this in check_kill_permission).
1606 if (!valid_signal(sig))
1609 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1611 EXPORT_SYMBOL(send_sig_info);
1613 #define __si_special(priv) \
1614 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1617 send_sig(int sig, struct task_struct *p, int priv)
1619 return send_sig_info(sig, __si_special(priv), p);
1621 EXPORT_SYMBOL(send_sig);
1623 void force_sig(int sig)
1625 struct kernel_siginfo info;
1627 clear_siginfo(&info);
1628 info.si_signo = sig;
1630 info.si_code = SI_KERNEL;
1633 force_sig_info(&info);
1635 EXPORT_SYMBOL(force_sig);
1638 * When things go south during signal handling, we
1639 * will force a SIGSEGV. And if the signal that caused
1640 * the problem was already a SIGSEGV, we'll want to
1641 * make sure we don't even try to deliver the signal..
1643 void force_sigsegv(int sig)
1645 struct task_struct *p = current;
1647 if (sig == SIGSEGV) {
1648 unsigned long flags;
1649 spin_lock_irqsave(&p->sighand->siglock, flags);
1650 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1651 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1656 int force_sig_fault_to_task(int sig, int code, void __user *addr
1657 ___ARCH_SI_TRAPNO(int trapno)
1658 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1659 , struct task_struct *t)
1661 struct kernel_siginfo info;
1663 clear_siginfo(&info);
1664 info.si_signo = sig;
1666 info.si_code = code;
1667 info.si_addr = addr;
1668 #ifdef __ARCH_SI_TRAPNO
1669 info.si_trapno = trapno;
1673 info.si_flags = flags;
1676 return force_sig_info_to_task(&info, t);
1679 int force_sig_fault(int sig, int code, void __user *addr
1680 ___ARCH_SI_TRAPNO(int trapno)
1681 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1683 return force_sig_fault_to_task(sig, code, addr
1684 ___ARCH_SI_TRAPNO(trapno)
1685 ___ARCH_SI_IA64(imm, flags, isr), current);
1688 int send_sig_fault(int sig, int code, void __user *addr
1689 ___ARCH_SI_TRAPNO(int trapno)
1690 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1691 , struct task_struct *t)
1693 struct kernel_siginfo info;
1695 clear_siginfo(&info);
1696 info.si_signo = sig;
1698 info.si_code = code;
1699 info.si_addr = addr;
1700 #ifdef __ARCH_SI_TRAPNO
1701 info.si_trapno = trapno;
1705 info.si_flags = flags;
1708 return send_sig_info(info.si_signo, &info, t);
1711 int force_sig_mceerr(int code, void __user *addr, short lsb)
1713 struct kernel_siginfo info;
1715 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1716 clear_siginfo(&info);
1717 info.si_signo = SIGBUS;
1719 info.si_code = code;
1720 info.si_addr = addr;
1721 info.si_addr_lsb = lsb;
1722 return force_sig_info(&info);
1725 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1727 struct kernel_siginfo info;
1729 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1730 clear_siginfo(&info);
1731 info.si_signo = SIGBUS;
1733 info.si_code = code;
1734 info.si_addr = addr;
1735 info.si_addr_lsb = lsb;
1736 return send_sig_info(info.si_signo, &info, t);
1738 EXPORT_SYMBOL(send_sig_mceerr);
1740 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1742 struct kernel_siginfo info;
1744 clear_siginfo(&info);
1745 info.si_signo = SIGSEGV;
1747 info.si_code = SEGV_BNDERR;
1748 info.si_addr = addr;
1749 info.si_lower = lower;
1750 info.si_upper = upper;
1751 return force_sig_info(&info);
1755 int force_sig_pkuerr(void __user *addr, u32 pkey)
1757 struct kernel_siginfo info;
1759 clear_siginfo(&info);
1760 info.si_signo = SIGSEGV;
1762 info.si_code = SEGV_PKUERR;
1763 info.si_addr = addr;
1764 info.si_pkey = pkey;
1765 return force_sig_info(&info);
1769 /* For the crazy architectures that include trap information in
1770 * the errno field, instead of an actual errno value.
1772 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1774 struct kernel_siginfo info;
1776 clear_siginfo(&info);
1777 info.si_signo = SIGTRAP;
1778 info.si_errno = errno;
1779 info.si_code = TRAP_HWBKPT;
1780 info.si_addr = addr;
1781 return force_sig_info(&info);
1784 int kill_pgrp(struct pid *pid, int sig, int priv)
1788 read_lock(&tasklist_lock);
1789 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1790 read_unlock(&tasklist_lock);
1794 EXPORT_SYMBOL(kill_pgrp);
1796 int kill_pid(struct pid *pid, int sig, int priv)
1798 return kill_pid_info(sig, __si_special(priv), pid);
1800 EXPORT_SYMBOL(kill_pid);
1803 * These functions support sending signals using preallocated sigqueue
1804 * structures. This is needed "because realtime applications cannot
1805 * afford to lose notifications of asynchronous events, like timer
1806 * expirations or I/O completions". In the case of POSIX Timers
1807 * we allocate the sigqueue structure from the timer_create. If this
1808 * allocation fails we are able to report the failure to the application
1809 * with an EAGAIN error.
1811 struct sigqueue *sigqueue_alloc(void)
1813 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1816 q->flags |= SIGQUEUE_PREALLOC;
1821 void sigqueue_free(struct sigqueue *q)
1823 unsigned long flags;
1824 spinlock_t *lock = ¤t->sighand->siglock;
1826 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1828 * We must hold ->siglock while testing q->list
1829 * to serialize with collect_signal() or with
1830 * __exit_signal()->flush_sigqueue().
1832 spin_lock_irqsave(lock, flags);
1833 q->flags &= ~SIGQUEUE_PREALLOC;
1835 * If it is queued it will be freed when dequeued,
1836 * like the "regular" sigqueue.
1838 if (!list_empty(&q->list))
1840 spin_unlock_irqrestore(lock, flags);
1846 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1848 int sig = q->info.si_signo;
1849 struct sigpending *pending;
1850 struct task_struct *t;
1851 unsigned long flags;
1854 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1858 t = pid_task(pid, type);
1859 if (!t || !likely(lock_task_sighand(t, &flags)))
1862 ret = 1; /* the signal is ignored */
1863 result = TRACE_SIGNAL_IGNORED;
1864 if (!prepare_signal(sig, t, false))
1868 if (unlikely(!list_empty(&q->list))) {
1870 * If an SI_TIMER entry is already queue just increment
1871 * the overrun count.
1873 BUG_ON(q->info.si_code != SI_TIMER);
1874 q->info.si_overrun++;
1875 result = TRACE_SIGNAL_ALREADY_PENDING;
1878 q->info.si_overrun = 0;
1880 signalfd_notify(t, sig);
1881 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1882 list_add_tail(&q->list, &pending->list);
1883 sigaddset(&pending->signal, sig);
1884 complete_signal(sig, t, type);
1885 result = TRACE_SIGNAL_DELIVERED;
1887 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
1888 unlock_task_sighand(t, &flags);
1894 static void do_notify_pidfd(struct task_struct *task)
1898 WARN_ON(task->exit_state == 0);
1899 pid = task_pid(task);
1900 wake_up_all(&pid->wait_pidfd);
1904 * Let a parent know about the death of a child.
1905 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1907 * Returns true if our parent ignored us and so we've switched to
1910 bool do_notify_parent(struct task_struct *tsk, int sig)
1912 struct kernel_siginfo info;
1913 unsigned long flags;
1914 struct sighand_struct *psig;
1915 bool autoreap = false;
1920 /* do_notify_parent_cldstop should have been called instead. */
1921 BUG_ON(task_is_stopped_or_traced(tsk));
1923 BUG_ON(!tsk->ptrace &&
1924 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1926 /* Wake up all pidfd waiters */
1927 do_notify_pidfd(tsk);
1929 if (sig != SIGCHLD) {
1931 * This is only possible if parent == real_parent.
1932 * Check if it has changed security domain.
1934 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
1938 clear_siginfo(&info);
1939 info.si_signo = sig;
1942 * We are under tasklist_lock here so our parent is tied to
1943 * us and cannot change.
1945 * task_active_pid_ns will always return the same pid namespace
1946 * until a task passes through release_task.
1948 * write_lock() currently calls preempt_disable() which is the
1949 * same as rcu_read_lock(), but according to Oleg, this is not
1950 * correct to rely on this
1953 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1954 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1958 task_cputime(tsk, &utime, &stime);
1959 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
1960 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
1962 info.si_status = tsk->exit_code & 0x7f;
1963 if (tsk->exit_code & 0x80)
1964 info.si_code = CLD_DUMPED;
1965 else if (tsk->exit_code & 0x7f)
1966 info.si_code = CLD_KILLED;
1968 info.si_code = CLD_EXITED;
1969 info.si_status = tsk->exit_code >> 8;
1972 psig = tsk->parent->sighand;
1973 spin_lock_irqsave(&psig->siglock, flags);
1974 if (!tsk->ptrace && sig == SIGCHLD &&
1975 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1976 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1978 * We are exiting and our parent doesn't care. POSIX.1
1979 * defines special semantics for setting SIGCHLD to SIG_IGN
1980 * or setting the SA_NOCLDWAIT flag: we should be reaped
1981 * automatically and not left for our parent's wait4 call.
1982 * Rather than having the parent do it as a magic kind of
1983 * signal handler, we just set this to tell do_exit that we
1984 * can be cleaned up without becoming a zombie. Note that
1985 * we still call __wake_up_parent in this case, because a
1986 * blocked sys_wait4 might now return -ECHILD.
1988 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1989 * is implementation-defined: we do (if you don't want
1990 * it, just use SIG_IGN instead).
1993 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1997 * Send with __send_signal as si_pid and si_uid are in the
1998 * parent's namespaces.
2000 if (valid_signal(sig) && sig)
2001 __send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false);
2002 __wake_up_parent(tsk, tsk->parent);
2003 spin_unlock_irqrestore(&psig->siglock, flags);
2009 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2010 * @tsk: task reporting the state change
2011 * @for_ptracer: the notification is for ptracer
2012 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2014 * Notify @tsk's parent that the stopped/continued state has changed. If
2015 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2016 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2019 * Must be called with tasklist_lock at least read locked.
2021 static void do_notify_parent_cldstop(struct task_struct *tsk,
2022 bool for_ptracer, int why)
2024 struct kernel_siginfo info;
2025 unsigned long flags;
2026 struct task_struct *parent;
2027 struct sighand_struct *sighand;
2031 parent = tsk->parent;
2033 tsk = tsk->group_leader;
2034 parent = tsk->real_parent;
2037 clear_siginfo(&info);
2038 info.si_signo = SIGCHLD;
2041 * see comment in do_notify_parent() about the following 4 lines
2044 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2045 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2048 task_cputime(tsk, &utime, &stime);
2049 info.si_utime = nsec_to_clock_t(utime);
2050 info.si_stime = nsec_to_clock_t(stime);
2055 info.si_status = SIGCONT;
2058 info.si_status = tsk->signal->group_exit_code & 0x7f;
2061 info.si_status = tsk->exit_code & 0x7f;
2067 sighand = parent->sighand;
2068 spin_lock_irqsave(&sighand->siglock, flags);
2069 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2070 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2071 __group_send_sig_info(SIGCHLD, &info, parent);
2073 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2075 __wake_up_parent(tsk, parent);
2076 spin_unlock_irqrestore(&sighand->siglock, flags);
2079 static inline bool may_ptrace_stop(void)
2081 if (!likely(current->ptrace))
2084 * Are we in the middle of do_coredump?
2085 * If so and our tracer is also part of the coredump stopping
2086 * is a deadlock situation, and pointless because our tracer
2087 * is dead so don't allow us to stop.
2088 * If SIGKILL was already sent before the caller unlocked
2089 * ->siglock we must see ->core_state != NULL. Otherwise it
2090 * is safe to enter schedule().
2092 * This is almost outdated, a task with the pending SIGKILL can't
2093 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2094 * after SIGKILL was already dequeued.
2096 if (unlikely(current->mm->core_state) &&
2097 unlikely(current->mm == current->parent->mm))
2104 * Return non-zero if there is a SIGKILL that should be waking us up.
2105 * Called with the siglock held.
2107 static bool sigkill_pending(struct task_struct *tsk)
2109 return sigismember(&tsk->pending.signal, SIGKILL) ||
2110 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
2114 * This must be called with current->sighand->siglock held.
2116 * This should be the path for all ptrace stops.
2117 * We always set current->last_siginfo while stopped here.
2118 * That makes it a way to test a stopped process for
2119 * being ptrace-stopped vs being job-control-stopped.
2121 * If we actually decide not to stop at all because the tracer
2122 * is gone, we keep current->exit_code unless clear_code.
2124 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2125 __releases(¤t->sighand->siglock)
2126 __acquires(¤t->sighand->siglock)
2128 bool gstop_done = false;
2130 if (arch_ptrace_stop_needed(exit_code, info)) {
2132 * The arch code has something special to do before a
2133 * ptrace stop. This is allowed to block, e.g. for faults
2134 * on user stack pages. We can't keep the siglock while
2135 * calling arch_ptrace_stop, so we must release it now.
2136 * To preserve proper semantics, we must do this before
2137 * any signal bookkeeping like checking group_stop_count.
2138 * Meanwhile, a SIGKILL could come in before we retake the
2139 * siglock. That must prevent us from sleeping in TASK_TRACED.
2140 * So after regaining the lock, we must check for SIGKILL.
2142 spin_unlock_irq(¤t->sighand->siglock);
2143 arch_ptrace_stop(exit_code, info);
2144 spin_lock_irq(¤t->sighand->siglock);
2145 if (sigkill_pending(current))
2149 set_special_state(TASK_TRACED);
2152 * We're committing to trapping. TRACED should be visible before
2153 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2154 * Also, transition to TRACED and updates to ->jobctl should be
2155 * atomic with respect to siglock and should be done after the arch
2156 * hook as siglock is released and regrabbed across it.
2161 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2163 * set_current_state() smp_wmb();
2165 * wait_task_stopped()
2166 * task_stopped_code()
2167 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2171 current->last_siginfo = info;
2172 current->exit_code = exit_code;
2175 * If @why is CLD_STOPPED, we're trapping to participate in a group
2176 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2177 * across siglock relocks since INTERRUPT was scheduled, PENDING
2178 * could be clear now. We act as if SIGCONT is received after
2179 * TASK_TRACED is entered - ignore it.
2181 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2182 gstop_done = task_participate_group_stop(current);
2184 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2185 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2186 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2187 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2189 /* entering a trap, clear TRAPPING */
2190 task_clear_jobctl_trapping(current);
2192 spin_unlock_irq(¤t->sighand->siglock);
2193 read_lock(&tasklist_lock);
2194 if (may_ptrace_stop()) {
2196 * Notify parents of the stop.
2198 * While ptraced, there are two parents - the ptracer and
2199 * the real_parent of the group_leader. The ptracer should
2200 * know about every stop while the real parent is only
2201 * interested in the completion of group stop. The states
2202 * for the two don't interact with each other. Notify
2203 * separately unless they're gonna be duplicates.
2205 do_notify_parent_cldstop(current, true, why);
2206 if (gstop_done && ptrace_reparented(current))
2207 do_notify_parent_cldstop(current, false, why);
2210 * Don't want to allow preemption here, because
2211 * sys_ptrace() needs this task to be inactive.
2213 * XXX: implement read_unlock_no_resched().
2216 read_unlock(&tasklist_lock);
2217 cgroup_enter_frozen();
2218 preempt_enable_no_resched();
2219 freezable_schedule();
2220 cgroup_leave_frozen(true);
2223 * By the time we got the lock, our tracer went away.
2224 * Don't drop the lock yet, another tracer may come.
2226 * If @gstop_done, the ptracer went away between group stop
2227 * completion and here. During detach, it would have set
2228 * JOBCTL_STOP_PENDING on us and we'll re-enter
2229 * TASK_STOPPED in do_signal_stop() on return, so notifying
2230 * the real parent of the group stop completion is enough.
2233 do_notify_parent_cldstop(current, false, why);
2235 /* tasklist protects us from ptrace_freeze_traced() */
2236 __set_current_state(TASK_RUNNING);
2238 current->exit_code = 0;
2239 read_unlock(&tasklist_lock);
2243 * We are back. Now reacquire the siglock before touching
2244 * last_siginfo, so that we are sure to have synchronized with
2245 * any signal-sending on another CPU that wants to examine it.
2247 spin_lock_irq(¤t->sighand->siglock);
2248 current->last_siginfo = NULL;
2250 /* LISTENING can be set only during STOP traps, clear it */
2251 current->jobctl &= ~JOBCTL_LISTENING;
2254 * Queued signals ignored us while we were stopped for tracing.
2255 * So check for any that we should take before resuming user mode.
2256 * This sets TIF_SIGPENDING, but never clears it.
2258 recalc_sigpending_tsk(current);
2261 static void ptrace_do_notify(int signr, int exit_code, int why)
2263 kernel_siginfo_t info;
2265 clear_siginfo(&info);
2266 info.si_signo = signr;
2267 info.si_code = exit_code;
2268 info.si_pid = task_pid_vnr(current);
2269 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2271 /* Let the debugger run. */
2272 ptrace_stop(exit_code, why, 1, &info);
2275 void ptrace_notify(int exit_code)
2277 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2278 if (unlikely(current->task_works))
2281 spin_lock_irq(¤t->sighand->siglock);
2282 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2283 spin_unlock_irq(¤t->sighand->siglock);
2287 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2288 * @signr: signr causing group stop if initiating
2290 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2291 * and participate in it. If already set, participate in the existing
2292 * group stop. If participated in a group stop (and thus slept), %true is
2293 * returned with siglock released.
2295 * If ptraced, this function doesn't handle stop itself. Instead,
2296 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2297 * untouched. The caller must ensure that INTERRUPT trap handling takes
2298 * places afterwards.
2301 * Must be called with @current->sighand->siglock held, which is released
2305 * %false if group stop is already cancelled or ptrace trap is scheduled.
2306 * %true if participated in group stop.
2308 static bool do_signal_stop(int signr)
2309 __releases(¤t->sighand->siglock)
2311 struct signal_struct *sig = current->signal;
2313 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2314 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2315 struct task_struct *t;
2317 /* signr will be recorded in task->jobctl for retries */
2318 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2320 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2321 unlikely(signal_group_exit(sig)))
2324 * There is no group stop already in progress. We must
2327 * While ptraced, a task may be resumed while group stop is
2328 * still in effect and then receive a stop signal and
2329 * initiate another group stop. This deviates from the
2330 * usual behavior as two consecutive stop signals can't
2331 * cause two group stops when !ptraced. That is why we
2332 * also check !task_is_stopped(t) below.
2334 * The condition can be distinguished by testing whether
2335 * SIGNAL_STOP_STOPPED is already set. Don't generate
2336 * group_exit_code in such case.
2338 * This is not necessary for SIGNAL_STOP_CONTINUED because
2339 * an intervening stop signal is required to cause two
2340 * continued events regardless of ptrace.
2342 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2343 sig->group_exit_code = signr;
2345 sig->group_stop_count = 0;
2347 if (task_set_jobctl_pending(current, signr | gstop))
2348 sig->group_stop_count++;
2351 while_each_thread(current, t) {
2353 * Setting state to TASK_STOPPED for a group
2354 * stop is always done with the siglock held,
2355 * so this check has no races.
2357 if (!task_is_stopped(t) &&
2358 task_set_jobctl_pending(t, signr | gstop)) {
2359 sig->group_stop_count++;
2360 if (likely(!(t->ptrace & PT_SEIZED)))
2361 signal_wake_up(t, 0);
2363 ptrace_trap_notify(t);
2368 if (likely(!current->ptrace)) {
2372 * If there are no other threads in the group, or if there
2373 * is a group stop in progress and we are the last to stop,
2374 * report to the parent.
2376 if (task_participate_group_stop(current))
2377 notify = CLD_STOPPED;
2379 set_special_state(TASK_STOPPED);
2380 spin_unlock_irq(¤t->sighand->siglock);
2383 * Notify the parent of the group stop completion. Because
2384 * we're not holding either the siglock or tasklist_lock
2385 * here, ptracer may attach inbetween; however, this is for
2386 * group stop and should always be delivered to the real
2387 * parent of the group leader. The new ptracer will get
2388 * its notification when this task transitions into
2392 read_lock(&tasklist_lock);
2393 do_notify_parent_cldstop(current, false, notify);
2394 read_unlock(&tasklist_lock);
2397 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2398 cgroup_enter_frozen();
2399 freezable_schedule();
2403 * While ptraced, group stop is handled by STOP trap.
2404 * Schedule it and let the caller deal with it.
2406 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2412 * do_jobctl_trap - take care of ptrace jobctl traps
2414 * When PT_SEIZED, it's used for both group stop and explicit
2415 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2416 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2417 * the stop signal; otherwise, %SIGTRAP.
2419 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2420 * number as exit_code and no siginfo.
2423 * Must be called with @current->sighand->siglock held, which may be
2424 * released and re-acquired before returning with intervening sleep.
2426 static void do_jobctl_trap(void)
2428 struct signal_struct *signal = current->signal;
2429 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2431 if (current->ptrace & PT_SEIZED) {
2432 if (!signal->group_stop_count &&
2433 !(signal->flags & SIGNAL_STOP_STOPPED))
2435 WARN_ON_ONCE(!signr);
2436 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2439 WARN_ON_ONCE(!signr);
2440 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2441 current->exit_code = 0;
2446 * do_freezer_trap - handle the freezer jobctl trap
2448 * Puts the task into frozen state, if only the task is not about to quit.
2449 * In this case it drops JOBCTL_TRAP_FREEZE.
2452 * Must be called with @current->sighand->siglock held,
2453 * which is always released before returning.
2455 static void do_freezer_trap(void)
2456 __releases(¤t->sighand->siglock)
2459 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2460 * let's make another loop to give it a chance to be handled.
2461 * In any case, we'll return back.
2463 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2464 JOBCTL_TRAP_FREEZE) {
2465 spin_unlock_irq(¤t->sighand->siglock);
2470 * Now we're sure that there is no pending fatal signal and no
2471 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2472 * immediately (if there is a non-fatal signal pending), and
2473 * put the task into sleep.
2475 __set_current_state(TASK_INTERRUPTIBLE);
2476 clear_thread_flag(TIF_SIGPENDING);
2477 spin_unlock_irq(¤t->sighand->siglock);
2478 cgroup_enter_frozen();
2479 freezable_schedule();
2482 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2485 * We do not check sig_kernel_stop(signr) but set this marker
2486 * unconditionally because we do not know whether debugger will
2487 * change signr. This flag has no meaning unless we are going
2488 * to stop after return from ptrace_stop(). In this case it will
2489 * be checked in do_signal_stop(), we should only stop if it was
2490 * not cleared by SIGCONT while we were sleeping. See also the
2491 * comment in dequeue_signal().
2493 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2494 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2496 /* We're back. Did the debugger cancel the sig? */
2497 signr = current->exit_code;
2501 current->exit_code = 0;
2504 * Update the siginfo structure if the signal has
2505 * changed. If the debugger wanted something
2506 * specific in the siginfo structure then it should
2507 * have updated *info via PTRACE_SETSIGINFO.
2509 if (signr != info->si_signo) {
2510 clear_siginfo(info);
2511 info->si_signo = signr;
2513 info->si_code = SI_USER;
2515 info->si_pid = task_pid_vnr(current->parent);
2516 info->si_uid = from_kuid_munged(current_user_ns(),
2517 task_uid(current->parent));
2521 /* If the (new) signal is now blocked, requeue it. */
2522 if (sigismember(¤t->blocked, signr)) {
2523 send_signal(signr, info, current, PIDTYPE_PID);
2530 bool get_signal(struct ksignal *ksig)
2532 struct sighand_struct *sighand = current->sighand;
2533 struct signal_struct *signal = current->signal;
2536 if (unlikely(current->task_works))
2539 if (unlikely(uprobe_deny_signal()))
2543 * Do this once, we can't return to user-mode if freezing() == T.
2544 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2545 * thus do not need another check after return.
2550 spin_lock_irq(&sighand->siglock);
2552 * Every stopped thread goes here after wakeup. Check to see if
2553 * we should notify the parent, prepare_signal(SIGCONT) encodes
2554 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2556 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2559 if (signal->flags & SIGNAL_CLD_CONTINUED)
2560 why = CLD_CONTINUED;
2564 signal->flags &= ~SIGNAL_CLD_MASK;
2566 spin_unlock_irq(&sighand->siglock);
2569 * Notify the parent that we're continuing. This event is
2570 * always per-process and doesn't make whole lot of sense
2571 * for ptracers, who shouldn't consume the state via
2572 * wait(2) either, but, for backward compatibility, notify
2573 * the ptracer of the group leader too unless it's gonna be
2576 read_lock(&tasklist_lock);
2577 do_notify_parent_cldstop(current, false, why);
2579 if (ptrace_reparented(current->group_leader))
2580 do_notify_parent_cldstop(current->group_leader,
2582 read_unlock(&tasklist_lock);
2587 /* Has this task already been marked for death? */
2588 if (signal_group_exit(signal)) {
2589 ksig->info.si_signo = signr = SIGKILL;
2590 sigdelset(¤t->pending.signal, SIGKILL);
2591 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2592 &sighand->action[SIGKILL - 1]);
2593 recalc_sigpending();
2598 struct k_sigaction *ka;
2600 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2604 if (unlikely(current->jobctl &
2605 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2606 if (current->jobctl & JOBCTL_TRAP_MASK) {
2608 spin_unlock_irq(&sighand->siglock);
2609 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2616 * If the task is leaving the frozen state, let's update
2617 * cgroup counters and reset the frozen bit.
2619 if (unlikely(cgroup_task_frozen(current))) {
2620 spin_unlock_irq(&sighand->siglock);
2621 cgroup_leave_frozen(false);
2626 * Signals generated by the execution of an instruction
2627 * need to be delivered before any other pending signals
2628 * so that the instruction pointer in the signal stack
2629 * frame points to the faulting instruction.
2631 signr = dequeue_synchronous_signal(&ksig->info);
2633 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2636 break; /* will return 0 */
2638 if (unlikely(current->ptrace) && signr != SIGKILL) {
2639 signr = ptrace_signal(signr, &ksig->info);
2644 ka = &sighand->action[signr-1];
2646 /* Trace actually delivered signals. */
2647 trace_signal_deliver(signr, &ksig->info, ka);
2649 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2651 if (ka->sa.sa_handler != SIG_DFL) {
2652 /* Run the handler. */
2655 if (ka->sa.sa_flags & SA_ONESHOT)
2656 ka->sa.sa_handler = SIG_DFL;
2658 break; /* will return non-zero "signr" value */
2662 * Now we are doing the default action for this signal.
2664 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2668 * Global init gets no signals it doesn't want.
2669 * Container-init gets no signals it doesn't want from same
2672 * Note that if global/container-init sees a sig_kernel_only()
2673 * signal here, the signal must have been generated internally
2674 * or must have come from an ancestor namespace. In either
2675 * case, the signal cannot be dropped.
2677 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2678 !sig_kernel_only(signr))
2681 if (sig_kernel_stop(signr)) {
2683 * The default action is to stop all threads in
2684 * the thread group. The job control signals
2685 * do nothing in an orphaned pgrp, but SIGSTOP
2686 * always works. Note that siglock needs to be
2687 * dropped during the call to is_orphaned_pgrp()
2688 * because of lock ordering with tasklist_lock.
2689 * This allows an intervening SIGCONT to be posted.
2690 * We need to check for that and bail out if necessary.
2692 if (signr != SIGSTOP) {
2693 spin_unlock_irq(&sighand->siglock);
2695 /* signals can be posted during this window */
2697 if (is_current_pgrp_orphaned())
2700 spin_lock_irq(&sighand->siglock);
2703 if (likely(do_signal_stop(ksig->info.si_signo))) {
2704 /* It released the siglock. */
2709 * We didn't actually stop, due to a race
2710 * with SIGCONT or something like that.
2716 spin_unlock_irq(&sighand->siglock);
2717 if (unlikely(cgroup_task_frozen(current)))
2718 cgroup_leave_frozen(true);
2721 * Anything else is fatal, maybe with a core dump.
2723 current->flags |= PF_SIGNALED;
2725 if (sig_kernel_coredump(signr)) {
2726 if (print_fatal_signals)
2727 print_fatal_signal(ksig->info.si_signo);
2728 proc_coredump_connector(current);
2730 * If it was able to dump core, this kills all
2731 * other threads in the group and synchronizes with
2732 * their demise. If we lost the race with another
2733 * thread getting here, it set group_exit_code
2734 * first and our do_group_exit call below will use
2735 * that value and ignore the one we pass it.
2737 do_coredump(&ksig->info);
2741 * Death signals, no core dump.
2743 do_group_exit(ksig->info.si_signo);
2746 spin_unlock_irq(&sighand->siglock);
2749 return ksig->sig > 0;
2753 * signal_delivered -
2754 * @ksig: kernel signal struct
2755 * @stepping: nonzero if debugger single-step or block-step in use
2757 * This function should be called when a signal has successfully been
2758 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2759 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2760 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2762 static void signal_delivered(struct ksignal *ksig, int stepping)
2766 /* A signal was successfully delivered, and the
2767 saved sigmask was stored on the signal frame,
2768 and will be restored by sigreturn. So we can
2769 simply clear the restore sigmask flag. */
2770 clear_restore_sigmask();
2772 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2773 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2774 sigaddset(&blocked, ksig->sig);
2775 set_current_blocked(&blocked);
2776 tracehook_signal_handler(stepping);
2779 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2782 force_sigsegv(ksig->sig);
2784 signal_delivered(ksig, stepping);
2788 * It could be that complete_signal() picked us to notify about the
2789 * group-wide signal. Other threads should be notified now to take
2790 * the shared signals in @which since we will not.
2792 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2795 struct task_struct *t;
2797 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2798 if (sigisemptyset(&retarget))
2802 while_each_thread(tsk, t) {
2803 if (t->flags & PF_EXITING)
2806 if (!has_pending_signals(&retarget, &t->blocked))
2808 /* Remove the signals this thread can handle. */
2809 sigandsets(&retarget, &retarget, &t->blocked);
2811 if (!signal_pending(t))
2812 signal_wake_up(t, 0);
2814 if (sigisemptyset(&retarget))
2819 void exit_signals(struct task_struct *tsk)
2825 * @tsk is about to have PF_EXITING set - lock out users which
2826 * expect stable threadgroup.
2828 cgroup_threadgroup_change_begin(tsk);
2830 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2831 tsk->flags |= PF_EXITING;
2832 cgroup_threadgroup_change_end(tsk);
2836 spin_lock_irq(&tsk->sighand->siglock);
2838 * From now this task is not visible for group-wide signals,
2839 * see wants_signal(), do_signal_stop().
2841 tsk->flags |= PF_EXITING;
2843 cgroup_threadgroup_change_end(tsk);
2845 if (!signal_pending(tsk))
2848 unblocked = tsk->blocked;
2849 signotset(&unblocked);
2850 retarget_shared_pending(tsk, &unblocked);
2852 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2853 task_participate_group_stop(tsk))
2854 group_stop = CLD_STOPPED;
2856 spin_unlock_irq(&tsk->sighand->siglock);
2859 * If group stop has completed, deliver the notification. This
2860 * should always go to the real parent of the group leader.
2862 if (unlikely(group_stop)) {
2863 read_lock(&tasklist_lock);
2864 do_notify_parent_cldstop(tsk, false, group_stop);
2865 read_unlock(&tasklist_lock);
2870 * System call entry points.
2874 * sys_restart_syscall - restart a system call
2876 SYSCALL_DEFINE0(restart_syscall)
2878 struct restart_block *restart = ¤t->restart_block;
2879 return restart->fn(restart);
2882 long do_no_restart_syscall(struct restart_block *param)
2887 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2889 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2890 sigset_t newblocked;
2891 /* A set of now blocked but previously unblocked signals. */
2892 sigandnsets(&newblocked, newset, ¤t->blocked);
2893 retarget_shared_pending(tsk, &newblocked);
2895 tsk->blocked = *newset;
2896 recalc_sigpending();
2900 * set_current_blocked - change current->blocked mask
2903 * It is wrong to change ->blocked directly, this helper should be used
2904 * to ensure the process can't miss a shared signal we are going to block.
2906 void set_current_blocked(sigset_t *newset)
2908 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2909 __set_current_blocked(newset);
2912 void __set_current_blocked(const sigset_t *newset)
2914 struct task_struct *tsk = current;
2917 * In case the signal mask hasn't changed, there is nothing we need
2918 * to do. The current->blocked shouldn't be modified by other task.
2920 if (sigequalsets(&tsk->blocked, newset))
2923 spin_lock_irq(&tsk->sighand->siglock);
2924 __set_task_blocked(tsk, newset);
2925 spin_unlock_irq(&tsk->sighand->siglock);
2929 * This is also useful for kernel threads that want to temporarily
2930 * (or permanently) block certain signals.
2932 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2933 * interface happily blocks "unblockable" signals like SIGKILL
2936 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2938 struct task_struct *tsk = current;
2941 /* Lockless, only current can change ->blocked, never from irq */
2943 *oldset = tsk->blocked;
2947 sigorsets(&newset, &tsk->blocked, set);
2950 sigandnsets(&newset, &tsk->blocked, set);
2959 __set_current_blocked(&newset);
2962 EXPORT_SYMBOL(sigprocmask);
2965 * The api helps set app-provided sigmasks.
2967 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2968 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
2970 * Note that it does set_restore_sigmask() in advance, so it must be always
2971 * paired with restore_saved_sigmask_unless() before return from syscall.
2973 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
2979 if (sigsetsize != sizeof(sigset_t))
2981 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
2984 set_restore_sigmask();
2985 current->saved_sigmask = current->blocked;
2986 set_current_blocked(&kmask);
2991 #ifdef CONFIG_COMPAT
2992 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
2999 if (sigsetsize != sizeof(compat_sigset_t))
3001 if (get_compat_sigset(&kmask, umask))
3004 set_restore_sigmask();
3005 current->saved_sigmask = current->blocked;
3006 set_current_blocked(&kmask);
3013 * sys_rt_sigprocmask - change the list of currently blocked signals
3014 * @how: whether to add, remove, or set signals
3015 * @nset: stores pending signals
3016 * @oset: previous value of signal mask if non-null
3017 * @sigsetsize: size of sigset_t type
3019 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3020 sigset_t __user *, oset, size_t, sigsetsize)
3022 sigset_t old_set, new_set;
3025 /* XXX: Don't preclude handling different sized sigset_t's. */
3026 if (sigsetsize != sizeof(sigset_t))
3029 old_set = current->blocked;
3032 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3034 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3036 error = sigprocmask(how, &new_set, NULL);
3042 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3049 #ifdef CONFIG_COMPAT
3050 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3051 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3053 sigset_t old_set = current->blocked;
3055 /* XXX: Don't preclude handling different sized sigset_t's. */
3056 if (sigsetsize != sizeof(sigset_t))
3062 if (get_compat_sigset(&new_set, nset))
3064 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3066 error = sigprocmask(how, &new_set, NULL);
3070 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3074 static void do_sigpending(sigset_t *set)
3076 spin_lock_irq(¤t->sighand->siglock);
3077 sigorsets(set, ¤t->pending.signal,
3078 ¤t->signal->shared_pending.signal);
3079 spin_unlock_irq(¤t->sighand->siglock);
3081 /* Outside the lock because only this thread touches it. */
3082 sigandsets(set, ¤t->blocked, set);
3086 * sys_rt_sigpending - examine a pending signal that has been raised
3088 * @uset: stores pending signals
3089 * @sigsetsize: size of sigset_t type or larger
3091 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3095 if (sigsetsize > sizeof(*uset))
3098 do_sigpending(&set);
3100 if (copy_to_user(uset, &set, sigsetsize))
3106 #ifdef CONFIG_COMPAT
3107 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3108 compat_size_t, sigsetsize)
3112 if (sigsetsize > sizeof(*uset))
3115 do_sigpending(&set);
3117 return put_compat_sigset(uset, &set, sigsetsize);
3121 static const struct {
3122 unsigned char limit, layout;
3124 [SIGILL] = { NSIGILL, SIL_FAULT },
3125 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3126 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3127 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3128 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3130 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3132 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3133 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3134 [SIGSYS] = { NSIGSYS, SIL_SYS },
3137 static bool known_siginfo_layout(unsigned sig, int si_code)
3139 if (si_code == SI_KERNEL)
3141 else if ((si_code > SI_USER)) {
3142 if (sig_specific_sicodes(sig)) {
3143 if (si_code <= sig_sicodes[sig].limit)
3146 else if (si_code <= NSIGPOLL)
3149 else if (si_code >= SI_DETHREAD)
3151 else if (si_code == SI_ASYNCNL)
3156 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3158 enum siginfo_layout layout = SIL_KILL;
3159 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3160 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3161 (si_code <= sig_sicodes[sig].limit)) {
3162 layout = sig_sicodes[sig].layout;
3163 /* Handle the exceptions */
3164 if ((sig == SIGBUS) &&
3165 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3166 layout = SIL_FAULT_MCEERR;
3167 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3168 layout = SIL_FAULT_BNDERR;
3170 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3171 layout = SIL_FAULT_PKUERR;
3174 else if (si_code <= NSIGPOLL)
3177 if (si_code == SI_TIMER)
3179 else if (si_code == SI_SIGIO)
3181 else if (si_code < 0)
3187 static inline char __user *si_expansion(const siginfo_t __user *info)
3189 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3192 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3194 char __user *expansion = si_expansion(to);
3195 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3197 if (clear_user(expansion, SI_EXPANSION_SIZE))
3202 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3203 const siginfo_t __user *from)
3205 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3206 char __user *expansion = si_expansion(from);
3207 char buf[SI_EXPANSION_SIZE];
3210 * An unknown si_code might need more than
3211 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3212 * extra bytes are 0. This guarantees copy_siginfo_to_user
3213 * will return this data to userspace exactly.
3215 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3217 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3225 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3226 const siginfo_t __user *from)
3228 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3230 to->si_signo = signo;
3231 return post_copy_siginfo_from_user(to, from);
3234 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3236 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3238 return post_copy_siginfo_from_user(to, from);
3241 #ifdef CONFIG_COMPAT
3242 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
3243 const struct kernel_siginfo *from)
3244 #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
3246 return __copy_siginfo_to_user32(to, from, in_x32_syscall());
3248 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3249 const struct kernel_siginfo *from, bool x32_ABI)
3252 struct compat_siginfo new;
3253 memset(&new, 0, sizeof(new));
3255 new.si_signo = from->si_signo;
3256 new.si_errno = from->si_errno;
3257 new.si_code = from->si_code;
3258 switch(siginfo_layout(from->si_signo, from->si_code)) {
3260 new.si_pid = from->si_pid;
3261 new.si_uid = from->si_uid;
3264 new.si_tid = from->si_tid;
3265 new.si_overrun = from->si_overrun;
3266 new.si_int = from->si_int;
3269 new.si_band = from->si_band;
3270 new.si_fd = from->si_fd;
3273 new.si_addr = ptr_to_compat(from->si_addr);
3274 #ifdef __ARCH_SI_TRAPNO
3275 new.si_trapno = from->si_trapno;
3278 case SIL_FAULT_MCEERR:
3279 new.si_addr = ptr_to_compat(from->si_addr);
3280 #ifdef __ARCH_SI_TRAPNO
3281 new.si_trapno = from->si_trapno;
3283 new.si_addr_lsb = from->si_addr_lsb;
3285 case SIL_FAULT_BNDERR:
3286 new.si_addr = ptr_to_compat(from->si_addr);
3287 #ifdef __ARCH_SI_TRAPNO
3288 new.si_trapno = from->si_trapno;
3290 new.si_lower = ptr_to_compat(from->si_lower);
3291 new.si_upper = ptr_to_compat(from->si_upper);
3293 case SIL_FAULT_PKUERR:
3294 new.si_addr = ptr_to_compat(from->si_addr);
3295 #ifdef __ARCH_SI_TRAPNO
3296 new.si_trapno = from->si_trapno;
3298 new.si_pkey = from->si_pkey;
3301 new.si_pid = from->si_pid;
3302 new.si_uid = from->si_uid;
3303 new.si_status = from->si_status;
3304 #ifdef CONFIG_X86_X32_ABI
3306 new._sifields._sigchld_x32._utime = from->si_utime;
3307 new._sifields._sigchld_x32._stime = from->si_stime;
3311 new.si_utime = from->si_utime;
3312 new.si_stime = from->si_stime;
3316 new.si_pid = from->si_pid;
3317 new.si_uid = from->si_uid;
3318 new.si_int = from->si_int;
3321 new.si_call_addr = ptr_to_compat(from->si_call_addr);
3322 new.si_syscall = from->si_syscall;
3323 new.si_arch = from->si_arch;
3327 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3333 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3334 const struct compat_siginfo *from)
3337 to->si_signo = from->si_signo;
3338 to->si_errno = from->si_errno;
3339 to->si_code = from->si_code;
3340 switch(siginfo_layout(from->si_signo, from->si_code)) {
3342 to->si_pid = from->si_pid;
3343 to->si_uid = from->si_uid;
3346 to->si_tid = from->si_tid;
3347 to->si_overrun = from->si_overrun;
3348 to->si_int = from->si_int;
3351 to->si_band = from->si_band;
3352 to->si_fd = from->si_fd;
3355 to->si_addr = compat_ptr(from->si_addr);
3356 #ifdef __ARCH_SI_TRAPNO
3357 to->si_trapno = from->si_trapno;
3360 case SIL_FAULT_MCEERR:
3361 to->si_addr = compat_ptr(from->si_addr);
3362 #ifdef __ARCH_SI_TRAPNO
3363 to->si_trapno = from->si_trapno;
3365 to->si_addr_lsb = from->si_addr_lsb;
3367 case SIL_FAULT_BNDERR:
3368 to->si_addr = compat_ptr(from->si_addr);
3369 #ifdef __ARCH_SI_TRAPNO
3370 to->si_trapno = from->si_trapno;
3372 to->si_lower = compat_ptr(from->si_lower);
3373 to->si_upper = compat_ptr(from->si_upper);
3375 case SIL_FAULT_PKUERR:
3376 to->si_addr = compat_ptr(from->si_addr);
3377 #ifdef __ARCH_SI_TRAPNO
3378 to->si_trapno = from->si_trapno;
3380 to->si_pkey = from->si_pkey;
3383 to->si_pid = from->si_pid;
3384 to->si_uid = from->si_uid;
3385 to->si_status = from->si_status;
3386 #ifdef CONFIG_X86_X32_ABI
3387 if (in_x32_syscall()) {
3388 to->si_utime = from->_sifields._sigchld_x32._utime;
3389 to->si_stime = from->_sifields._sigchld_x32._stime;
3393 to->si_utime = from->si_utime;
3394 to->si_stime = from->si_stime;
3398 to->si_pid = from->si_pid;
3399 to->si_uid = from->si_uid;
3400 to->si_int = from->si_int;
3403 to->si_call_addr = compat_ptr(from->si_call_addr);
3404 to->si_syscall = from->si_syscall;
3405 to->si_arch = from->si_arch;
3411 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3412 const struct compat_siginfo __user *ufrom)
3414 struct compat_siginfo from;
3416 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3419 from.si_signo = signo;
3420 return post_copy_siginfo_from_user32(to, &from);
3423 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3424 const struct compat_siginfo __user *ufrom)
3426 struct compat_siginfo from;
3428 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3431 return post_copy_siginfo_from_user32(to, &from);
3433 #endif /* CONFIG_COMPAT */
3436 * do_sigtimedwait - wait for queued signals specified in @which
3437 * @which: queued signals to wait for
3438 * @info: if non-null, the signal's siginfo is returned here
3439 * @ts: upper bound on process time suspension
3441 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3442 const struct timespec64 *ts)
3444 ktime_t *to = NULL, timeout = KTIME_MAX;
3445 struct task_struct *tsk = current;
3446 sigset_t mask = *which;
3450 if (!timespec64_valid(ts))
3452 timeout = timespec64_to_ktime(*ts);
3457 * Invert the set of allowed signals to get those we want to block.
3459 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3462 spin_lock_irq(&tsk->sighand->siglock);
3463 sig = dequeue_signal(tsk, &mask, info);
3464 if (!sig && timeout) {
3466 * None ready, temporarily unblock those we're interested
3467 * while we are sleeping in so that we'll be awakened when
3468 * they arrive. Unblocking is always fine, we can avoid
3469 * set_current_blocked().
3471 tsk->real_blocked = tsk->blocked;
3472 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3473 recalc_sigpending();
3474 spin_unlock_irq(&tsk->sighand->siglock);
3476 __set_current_state(TASK_INTERRUPTIBLE);
3477 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3479 spin_lock_irq(&tsk->sighand->siglock);
3480 __set_task_blocked(tsk, &tsk->real_blocked);
3481 sigemptyset(&tsk->real_blocked);
3482 sig = dequeue_signal(tsk, &mask, info);
3484 spin_unlock_irq(&tsk->sighand->siglock);
3488 return ret ? -EINTR : -EAGAIN;
3492 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3494 * @uthese: queued signals to wait for
3495 * @uinfo: if non-null, the signal's siginfo is returned here
3496 * @uts: upper bound on process time suspension
3497 * @sigsetsize: size of sigset_t type
3499 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3500 siginfo_t __user *, uinfo,
3501 const struct __kernel_timespec __user *, uts,
3505 struct timespec64 ts;
3506 kernel_siginfo_t info;
3509 /* XXX: Don't preclude handling different sized sigset_t's. */
3510 if (sigsetsize != sizeof(sigset_t))
3513 if (copy_from_user(&these, uthese, sizeof(these)))
3517 if (get_timespec64(&ts, uts))
3521 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3523 if (ret > 0 && uinfo) {
3524 if (copy_siginfo_to_user(uinfo, &info))
3531 #ifdef CONFIG_COMPAT_32BIT_TIME
3532 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3533 siginfo_t __user *, uinfo,
3534 const struct old_timespec32 __user *, uts,
3538 struct timespec64 ts;
3539 kernel_siginfo_t info;
3542 if (sigsetsize != sizeof(sigset_t))
3545 if (copy_from_user(&these, uthese, sizeof(these)))
3549 if (get_old_timespec32(&ts, uts))
3553 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3555 if (ret > 0 && uinfo) {
3556 if (copy_siginfo_to_user(uinfo, &info))
3564 #ifdef CONFIG_COMPAT
3565 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3566 struct compat_siginfo __user *, uinfo,
3567 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3570 struct timespec64 t;
3571 kernel_siginfo_t info;
3574 if (sigsetsize != sizeof(sigset_t))
3577 if (get_compat_sigset(&s, uthese))
3581 if (get_timespec64(&t, uts))
3585 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3587 if (ret > 0 && uinfo) {
3588 if (copy_siginfo_to_user32(uinfo, &info))
3595 #ifdef CONFIG_COMPAT_32BIT_TIME
3596 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3597 struct compat_siginfo __user *, uinfo,
3598 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3601 struct timespec64 t;
3602 kernel_siginfo_t info;
3605 if (sigsetsize != sizeof(sigset_t))
3608 if (get_compat_sigset(&s, uthese))
3612 if (get_old_timespec32(&t, uts))
3616 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3618 if (ret > 0 && uinfo) {
3619 if (copy_siginfo_to_user32(uinfo, &info))
3628 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3630 clear_siginfo(info);
3631 info->si_signo = sig;
3633 info->si_code = SI_USER;
3634 info->si_pid = task_tgid_vnr(current);
3635 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3639 * sys_kill - send a signal to a process
3640 * @pid: the PID of the process
3641 * @sig: signal to be sent
3643 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3645 struct kernel_siginfo info;
3647 prepare_kill_siginfo(sig, &info);
3649 return kill_something_info(sig, &info, pid);
3653 * Verify that the signaler and signalee either are in the same pid namespace
3654 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3657 static bool access_pidfd_pidns(struct pid *pid)
3659 struct pid_namespace *active = task_active_pid_ns(current);
3660 struct pid_namespace *p = ns_of_pid(pid);
3673 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, siginfo_t *info)
3675 #ifdef CONFIG_COMPAT
3677 * Avoid hooking up compat syscalls and instead handle necessary
3678 * conversions here. Note, this is a stop-gap measure and should not be
3679 * considered a generic solution.
3681 if (in_compat_syscall())
3682 return copy_siginfo_from_user32(
3683 kinfo, (struct compat_siginfo __user *)info);
3685 return copy_siginfo_from_user(kinfo, info);
3688 static struct pid *pidfd_to_pid(const struct file *file)
3692 pid = pidfd_pid(file);
3696 return tgid_pidfd_to_pid(file);
3700 * sys_pidfd_send_signal - Signal a process through a pidfd
3701 * @pidfd: file descriptor of the process
3702 * @sig: signal to send
3703 * @info: signal info
3704 * @flags: future flags
3706 * The syscall currently only signals via PIDTYPE_PID which covers
3707 * kill(<positive-pid>, <signal>. It does not signal threads or process
3709 * In order to extend the syscall to threads and process groups the @flags
3710 * argument should be used. In essence, the @flags argument will determine
3711 * what is signaled and not the file descriptor itself. Put in other words,
3712 * grouping is a property of the flags argument not a property of the file
3715 * Return: 0 on success, negative errno on failure
3717 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3718 siginfo_t __user *, info, unsigned int, flags)
3723 kernel_siginfo_t kinfo;
3725 /* Enforce flags be set to 0 until we add an extension. */
3733 /* Is this a pidfd? */
3734 pid = pidfd_to_pid(f.file);
3741 if (!access_pidfd_pidns(pid))
3745 ret = copy_siginfo_from_user_any(&kinfo, info);
3750 if (unlikely(sig != kinfo.si_signo))
3753 /* Only allow sending arbitrary signals to yourself. */
3755 if ((task_pid(current) != pid) &&
3756 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3759 prepare_kill_siginfo(sig, &kinfo);
3762 ret = kill_pid_info(sig, &kinfo, pid);
3770 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3772 struct task_struct *p;
3776 p = find_task_by_vpid(pid);
3777 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3778 error = check_kill_permission(sig, info, p);
3780 * The null signal is a permissions and process existence
3781 * probe. No signal is actually delivered.
3783 if (!error && sig) {
3784 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3786 * If lock_task_sighand() failed we pretend the task
3787 * dies after receiving the signal. The window is tiny,
3788 * and the signal is private anyway.
3790 if (unlikely(error == -ESRCH))
3799 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3801 struct kernel_siginfo info;
3803 clear_siginfo(&info);
3804 info.si_signo = sig;
3806 info.si_code = SI_TKILL;
3807 info.si_pid = task_tgid_vnr(current);
3808 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3810 return do_send_specific(tgid, pid, sig, &info);
3814 * sys_tgkill - send signal to one specific thread
3815 * @tgid: the thread group ID of the thread
3816 * @pid: the PID of the thread
3817 * @sig: signal to be sent
3819 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3820 * exists but it's not belonging to the target process anymore. This
3821 * method solves the problem of threads exiting and PIDs getting reused.
3823 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3825 /* This is only valid for single tasks */
3826 if (pid <= 0 || tgid <= 0)
3829 return do_tkill(tgid, pid, sig);
3833 * sys_tkill - send signal to one specific task
3834 * @pid: the PID of the task
3835 * @sig: signal to be sent
3837 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3839 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3841 /* This is only valid for single tasks */
3845 return do_tkill(0, pid, sig);
3848 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3850 /* Not even root can pretend to send signals from the kernel.
3851 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3853 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3854 (task_pid_vnr(current) != pid))
3857 /* POSIX.1b doesn't mention process groups. */
3858 return kill_proc_info(sig, info, pid);
3862 * sys_rt_sigqueueinfo - send signal information to a signal
3863 * @pid: the PID of the thread
3864 * @sig: signal to be sent
3865 * @uinfo: signal info to be sent
3867 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3868 siginfo_t __user *, uinfo)
3870 kernel_siginfo_t info;
3871 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3874 return do_rt_sigqueueinfo(pid, sig, &info);
3877 #ifdef CONFIG_COMPAT
3878 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3881 struct compat_siginfo __user *, uinfo)
3883 kernel_siginfo_t info;
3884 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3887 return do_rt_sigqueueinfo(pid, sig, &info);
3891 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
3893 /* This is only valid for single tasks */
3894 if (pid <= 0 || tgid <= 0)
3897 /* Not even root can pretend to send signals from the kernel.
3898 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3900 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3901 (task_pid_vnr(current) != pid))
3904 return do_send_specific(tgid, pid, sig, info);
3907 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3908 siginfo_t __user *, uinfo)
3910 kernel_siginfo_t info;
3911 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3914 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3917 #ifdef CONFIG_COMPAT
3918 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3922 struct compat_siginfo __user *, uinfo)
3924 kernel_siginfo_t info;
3925 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3928 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3933 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3935 void kernel_sigaction(int sig, __sighandler_t action)
3937 spin_lock_irq(¤t->sighand->siglock);
3938 current->sighand->action[sig - 1].sa.sa_handler = action;
3939 if (action == SIG_IGN) {
3943 sigaddset(&mask, sig);
3945 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3946 flush_sigqueue_mask(&mask, ¤t->pending);
3947 recalc_sigpending();
3949 spin_unlock_irq(¤t->sighand->siglock);
3951 EXPORT_SYMBOL(kernel_sigaction);
3953 void __weak sigaction_compat_abi(struct k_sigaction *act,
3954 struct k_sigaction *oact)
3958 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3960 struct task_struct *p = current, *t;
3961 struct k_sigaction *k;
3964 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3967 k = &p->sighand->action[sig-1];
3969 spin_lock_irq(&p->sighand->siglock);
3973 sigaction_compat_abi(act, oact);
3976 sigdelsetmask(&act->sa.sa_mask,
3977 sigmask(SIGKILL) | sigmask(SIGSTOP));
3981 * "Setting a signal action to SIG_IGN for a signal that is
3982 * pending shall cause the pending signal to be discarded,
3983 * whether or not it is blocked."
3985 * "Setting a signal action to SIG_DFL for a signal that is
3986 * pending and whose default action is to ignore the signal
3987 * (for example, SIGCHLD), shall cause the pending signal to
3988 * be discarded, whether or not it is blocked"
3990 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3992 sigaddset(&mask, sig);
3993 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3994 for_each_thread(p, t)
3995 flush_sigqueue_mask(&mask, &t->pending);
3999 spin_unlock_irq(&p->sighand->siglock);
4004 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4007 struct task_struct *t = current;
4010 memset(oss, 0, sizeof(stack_t));
4011 oss->ss_sp = (void __user *) t->sas_ss_sp;
4012 oss->ss_size = t->sas_ss_size;
4013 oss->ss_flags = sas_ss_flags(sp) |
4014 (current->sas_ss_flags & SS_FLAG_BITS);
4018 void __user *ss_sp = ss->ss_sp;
4019 size_t ss_size = ss->ss_size;
4020 unsigned ss_flags = ss->ss_flags;
4023 if (unlikely(on_sig_stack(sp)))
4026 ss_mode = ss_flags & ~SS_FLAG_BITS;
4027 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4031 if (ss_mode == SS_DISABLE) {
4035 if (unlikely(ss_size < min_ss_size))
4039 t->sas_ss_sp = (unsigned long) ss_sp;
4040 t->sas_ss_size = ss_size;
4041 t->sas_ss_flags = ss_flags;
4046 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4050 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4052 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4053 current_user_stack_pointer(),
4055 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4060 int restore_altstack(const stack_t __user *uss)
4063 if (copy_from_user(&new, uss, sizeof(stack_t)))
4065 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4067 /* squash all but EFAULT for now */
4071 int __save_altstack(stack_t __user *uss, unsigned long sp)
4073 struct task_struct *t = current;
4074 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4075 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4076 __put_user(t->sas_ss_size, &uss->ss_size);
4079 if (t->sas_ss_flags & SS_AUTODISARM)
4084 #ifdef CONFIG_COMPAT
4085 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4086 compat_stack_t __user *uoss_ptr)
4092 compat_stack_t uss32;
4093 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4095 uss.ss_sp = compat_ptr(uss32.ss_sp);
4096 uss.ss_flags = uss32.ss_flags;
4097 uss.ss_size = uss32.ss_size;
4099 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4100 compat_user_stack_pointer(),
4101 COMPAT_MINSIGSTKSZ);
4102 if (ret >= 0 && uoss_ptr) {
4104 memset(&old, 0, sizeof(old));
4105 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4106 old.ss_flags = uoss.ss_flags;
4107 old.ss_size = uoss.ss_size;
4108 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4114 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4115 const compat_stack_t __user *, uss_ptr,
4116 compat_stack_t __user *, uoss_ptr)
4118 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4121 int compat_restore_altstack(const compat_stack_t __user *uss)
4123 int err = do_compat_sigaltstack(uss, NULL);
4124 /* squash all but -EFAULT for now */
4125 return err == -EFAULT ? err : 0;
4128 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4131 struct task_struct *t = current;
4132 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4134 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4135 __put_user(t->sas_ss_size, &uss->ss_size);
4138 if (t->sas_ss_flags & SS_AUTODISARM)
4144 #ifdef __ARCH_WANT_SYS_SIGPENDING
4147 * sys_sigpending - examine pending signals
4148 * @uset: where mask of pending signal is returned
4150 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4154 if (sizeof(old_sigset_t) > sizeof(*uset))
4157 do_sigpending(&set);
4159 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4165 #ifdef CONFIG_COMPAT
4166 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4170 do_sigpending(&set);
4172 return put_user(set.sig[0], set32);
4178 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4180 * sys_sigprocmask - examine and change blocked signals
4181 * @how: whether to add, remove, or set signals
4182 * @nset: signals to add or remove (if non-null)
4183 * @oset: previous value of signal mask if non-null
4185 * Some platforms have their own version with special arguments;
4186 * others support only sys_rt_sigprocmask.
4189 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4190 old_sigset_t __user *, oset)
4192 old_sigset_t old_set, new_set;
4193 sigset_t new_blocked;
4195 old_set = current->blocked.sig[0];
4198 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4201 new_blocked = current->blocked;
4205 sigaddsetmask(&new_blocked, new_set);
4208 sigdelsetmask(&new_blocked, new_set);
4211 new_blocked.sig[0] = new_set;
4217 set_current_blocked(&new_blocked);
4221 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4227 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4229 #ifndef CONFIG_ODD_RT_SIGACTION
4231 * sys_rt_sigaction - alter an action taken by a process
4232 * @sig: signal to be sent
4233 * @act: new sigaction
4234 * @oact: used to save the previous sigaction
4235 * @sigsetsize: size of sigset_t type
4237 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4238 const struct sigaction __user *, act,
4239 struct sigaction __user *, oact,
4242 struct k_sigaction new_sa, old_sa;
4245 /* XXX: Don't preclude handling different sized sigset_t's. */
4246 if (sigsetsize != sizeof(sigset_t))
4249 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4252 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4256 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4261 #ifdef CONFIG_COMPAT
4262 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4263 const struct compat_sigaction __user *, act,
4264 struct compat_sigaction __user *, oact,
4265 compat_size_t, sigsetsize)
4267 struct k_sigaction new_ka, old_ka;
4268 #ifdef __ARCH_HAS_SA_RESTORER
4269 compat_uptr_t restorer;
4273 /* XXX: Don't preclude handling different sized sigset_t's. */
4274 if (sigsetsize != sizeof(compat_sigset_t))
4278 compat_uptr_t handler;
4279 ret = get_user(handler, &act->sa_handler);
4280 new_ka.sa.sa_handler = compat_ptr(handler);
4281 #ifdef __ARCH_HAS_SA_RESTORER
4282 ret |= get_user(restorer, &act->sa_restorer);
4283 new_ka.sa.sa_restorer = compat_ptr(restorer);
4285 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4286 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4291 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4293 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4295 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4296 sizeof(oact->sa_mask));
4297 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4298 #ifdef __ARCH_HAS_SA_RESTORER
4299 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4300 &oact->sa_restorer);
4306 #endif /* !CONFIG_ODD_RT_SIGACTION */
4308 #ifdef CONFIG_OLD_SIGACTION
4309 SYSCALL_DEFINE3(sigaction, int, sig,
4310 const struct old_sigaction __user *, act,
4311 struct old_sigaction __user *, oact)
4313 struct k_sigaction new_ka, old_ka;
4318 if (!access_ok(act, sizeof(*act)) ||
4319 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4320 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4321 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4322 __get_user(mask, &act->sa_mask))
4324 #ifdef __ARCH_HAS_KA_RESTORER
4325 new_ka.ka_restorer = NULL;
4327 siginitset(&new_ka.sa.sa_mask, mask);
4330 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4333 if (!access_ok(oact, sizeof(*oact)) ||
4334 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4335 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4336 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4337 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4344 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4345 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4346 const struct compat_old_sigaction __user *, act,
4347 struct compat_old_sigaction __user *, oact)
4349 struct k_sigaction new_ka, old_ka;
4351 compat_old_sigset_t mask;
4352 compat_uptr_t handler, restorer;
4355 if (!access_ok(act, sizeof(*act)) ||
4356 __get_user(handler, &act->sa_handler) ||
4357 __get_user(restorer, &act->sa_restorer) ||
4358 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4359 __get_user(mask, &act->sa_mask))
4362 #ifdef __ARCH_HAS_KA_RESTORER
4363 new_ka.ka_restorer = NULL;
4365 new_ka.sa.sa_handler = compat_ptr(handler);
4366 new_ka.sa.sa_restorer = compat_ptr(restorer);
4367 siginitset(&new_ka.sa.sa_mask, mask);
4370 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4373 if (!access_ok(oact, sizeof(*oact)) ||
4374 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4375 &oact->sa_handler) ||
4376 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4377 &oact->sa_restorer) ||
4378 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4379 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4386 #ifdef CONFIG_SGETMASK_SYSCALL
4389 * For backwards compatibility. Functionality superseded by sigprocmask.
4391 SYSCALL_DEFINE0(sgetmask)
4394 return current->blocked.sig[0];
4397 SYSCALL_DEFINE1(ssetmask, int, newmask)
4399 int old = current->blocked.sig[0];
4402 siginitset(&newset, newmask);
4403 set_current_blocked(&newset);
4407 #endif /* CONFIG_SGETMASK_SYSCALL */
4409 #ifdef __ARCH_WANT_SYS_SIGNAL
4411 * For backwards compatibility. Functionality superseded by sigaction.
4413 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4415 struct k_sigaction new_sa, old_sa;
4418 new_sa.sa.sa_handler = handler;
4419 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4420 sigemptyset(&new_sa.sa.sa_mask);
4422 ret = do_sigaction(sig, &new_sa, &old_sa);
4424 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4426 #endif /* __ARCH_WANT_SYS_SIGNAL */
4428 #ifdef __ARCH_WANT_SYS_PAUSE
4430 SYSCALL_DEFINE0(pause)
4432 while (!signal_pending(current)) {
4433 __set_current_state(TASK_INTERRUPTIBLE);
4436 return -ERESTARTNOHAND;
4441 static int sigsuspend(sigset_t *set)
4443 current->saved_sigmask = current->blocked;
4444 set_current_blocked(set);
4446 while (!signal_pending(current)) {
4447 __set_current_state(TASK_INTERRUPTIBLE);
4450 set_restore_sigmask();
4451 return -ERESTARTNOHAND;
4455 * sys_rt_sigsuspend - replace the signal mask for a value with the
4456 * @unewset value until a signal is received
4457 * @unewset: new signal mask value
4458 * @sigsetsize: size of sigset_t type
4460 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4464 /* XXX: Don't preclude handling different sized sigset_t's. */
4465 if (sigsetsize != sizeof(sigset_t))
4468 if (copy_from_user(&newset, unewset, sizeof(newset)))
4470 return sigsuspend(&newset);
4473 #ifdef CONFIG_COMPAT
4474 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4478 /* XXX: Don't preclude handling different sized sigset_t's. */
4479 if (sigsetsize != sizeof(sigset_t))
4482 if (get_compat_sigset(&newset, unewset))
4484 return sigsuspend(&newset);
4488 #ifdef CONFIG_OLD_SIGSUSPEND
4489 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4492 siginitset(&blocked, mask);
4493 return sigsuspend(&blocked);
4496 #ifdef CONFIG_OLD_SIGSUSPEND3
4497 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4500 siginitset(&blocked, mask);
4501 return sigsuspend(&blocked);
4505 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4510 static inline void siginfo_buildtime_checks(void)
4512 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4514 /* Verify the offsets in the two siginfos match */
4515 #define CHECK_OFFSET(field) \
4516 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4519 CHECK_OFFSET(si_pid);
4520 CHECK_OFFSET(si_uid);
4523 CHECK_OFFSET(si_tid);
4524 CHECK_OFFSET(si_overrun);
4525 CHECK_OFFSET(si_value);
4528 CHECK_OFFSET(si_pid);
4529 CHECK_OFFSET(si_uid);
4530 CHECK_OFFSET(si_value);
4533 CHECK_OFFSET(si_pid);
4534 CHECK_OFFSET(si_uid);
4535 CHECK_OFFSET(si_status);
4536 CHECK_OFFSET(si_utime);
4537 CHECK_OFFSET(si_stime);
4540 CHECK_OFFSET(si_addr);
4541 CHECK_OFFSET(si_addr_lsb);
4542 CHECK_OFFSET(si_lower);
4543 CHECK_OFFSET(si_upper);
4544 CHECK_OFFSET(si_pkey);
4547 CHECK_OFFSET(si_band);
4548 CHECK_OFFSET(si_fd);
4551 CHECK_OFFSET(si_call_addr);
4552 CHECK_OFFSET(si_syscall);
4553 CHECK_OFFSET(si_arch);
4557 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4558 offsetof(struct siginfo, si_addr));
4559 if (sizeof(int) == sizeof(void __user *)) {
4560 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4561 sizeof(void __user *));
4563 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4564 sizeof_field(struct siginfo, si_uid)) !=
4565 sizeof(void __user *));
4566 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4567 offsetof(struct siginfo, si_uid));
4569 #ifdef CONFIG_COMPAT
4570 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4571 offsetof(struct compat_siginfo, si_addr));
4572 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4573 sizeof(compat_uptr_t));
4574 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4575 sizeof_field(struct siginfo, si_pid));
4579 void __init signals_init(void)
4581 siginfo_buildtime_checks();
4583 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
4586 #ifdef CONFIG_KGDB_KDB
4587 #include <linux/kdb.h>
4589 * kdb_send_sig - Allows kdb to send signals without exposing
4590 * signal internals. This function checks if the required locks are
4591 * available before calling the main signal code, to avoid kdb
4594 void kdb_send_sig(struct task_struct *t, int sig)
4596 static struct task_struct *kdb_prev_t;
4598 if (!spin_trylock(&t->sighand->siglock)) {
4599 kdb_printf("Can't do kill command now.\n"
4600 "The sigmask lock is held somewhere else in "
4601 "kernel, try again later\n");
4604 new_t = kdb_prev_t != t;
4606 if (t->state != TASK_RUNNING && new_t) {
4607 spin_unlock(&t->sighand->siglock);
4608 kdb_printf("Process is not RUNNING, sending a signal from "
4609 "kdb risks deadlock\n"
4610 "on the run queue locks. "
4611 "The signal has _not_ been sent.\n"
4612 "Reissue the kill command if you want to risk "
4616 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4617 spin_unlock(&t->sighand->siglock);
4619 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4622 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4624 #endif /* CONFIG_KGDB_KDB */