1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
9 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
10 * Changes to use preallocated sigqueue structures
11 * to allow signals to be sent reliably.
14 #include <linux/slab.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/debug.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/sched/cputime.h>
23 #include <linux/file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/tty.h>
27 #include <linux/binfmts.h>
28 #include <linux/coredump.h>
29 #include <linux/security.h>
30 #include <linux/syscalls.h>
31 #include <linux/ptrace.h>
32 #include <linux/signal.h>
33 #include <linux/signalfd.h>
34 #include <linux/ratelimit.h>
35 #include <linux/tracehook.h>
36 #include <linux/capability.h>
37 #include <linux/freezer.h>
38 #include <linux/pid_namespace.h>
39 #include <linux/nsproxy.h>
40 #include <linux/user_namespace.h>
41 #include <linux/uprobes.h>
42 #include <linux/compat.h>
43 #include <linux/cn_proc.h>
44 #include <linux/compiler.h>
45 #include <linux/posix-timers.h>
46 #include <linux/livepatch.h>
47 #include <linux/cgroup.h>
48 #include <linux/audit.h>
50 #define CREATE_TRACE_POINTS
51 #include <trace/events/signal.h>
53 #include <asm/param.h>
54 #include <linux/uaccess.h>
55 #include <asm/unistd.h>
56 #include <asm/siginfo.h>
57 #include <asm/cacheflush.h>
60 * SLAB caches for signal bits.
63 static struct kmem_cache *sigqueue_cachep;
65 int print_fatal_signals __read_mostly;
67 static void __user *sig_handler(struct task_struct *t, int sig)
69 return t->sighand->action[sig - 1].sa.sa_handler;
72 static inline bool sig_handler_ignored(void __user *handler, int sig)
74 /* Is it explicitly or implicitly ignored? */
75 return handler == SIG_IGN ||
76 (handler == SIG_DFL && sig_kernel_ignore(sig));
79 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
83 handler = sig_handler(t, sig);
85 /* SIGKILL and SIGSTOP may not be sent to the global init */
86 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
89 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
90 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
93 /* Only allow kernel generated signals to this kthread */
94 if (unlikely((t->flags & PF_KTHREAD) &&
95 (handler == SIG_KTHREAD_KERNEL) && !force))
98 return sig_handler_ignored(handler, sig);
101 static bool sig_ignored(struct task_struct *t, int sig, bool force)
104 * Blocked signals are never ignored, since the
105 * signal handler may change by the time it is
108 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
112 * Tracers may want to know about even ignored signal unless it
113 * is SIGKILL which can't be reported anyway but can be ignored
114 * by SIGNAL_UNKILLABLE task.
116 if (t->ptrace && sig != SIGKILL)
119 return sig_task_ignored(t, sig, force);
123 * Re-calculate pending state from the set of locally pending
124 * signals, globally pending signals, and blocked signals.
126 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
131 switch (_NSIG_WORDS) {
133 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
134 ready |= signal->sig[i] &~ blocked->sig[i];
137 case 4: ready = signal->sig[3] &~ blocked->sig[3];
138 ready |= signal->sig[2] &~ blocked->sig[2];
139 ready |= signal->sig[1] &~ blocked->sig[1];
140 ready |= signal->sig[0] &~ blocked->sig[0];
143 case 2: ready = signal->sig[1] &~ blocked->sig[1];
144 ready |= signal->sig[0] &~ blocked->sig[0];
147 case 1: ready = signal->sig[0] &~ blocked->sig[0];
152 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
154 static bool recalc_sigpending_tsk(struct task_struct *t)
156 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
157 PENDING(&t->pending, &t->blocked) ||
158 PENDING(&t->signal->shared_pending, &t->blocked) ||
159 cgroup_task_frozen(t)) {
160 set_tsk_thread_flag(t, TIF_SIGPENDING);
165 * We must never clear the flag in another thread, or in current
166 * when it's possible the current syscall is returning -ERESTART*.
167 * So we don't clear it here, and only callers who know they should do.
173 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
174 * This is superfluous when called on current, the wakeup is a harmless no-op.
176 void recalc_sigpending_and_wake(struct task_struct *t)
178 if (recalc_sigpending_tsk(t))
179 signal_wake_up(t, 0);
182 void recalc_sigpending(void)
184 if (!recalc_sigpending_tsk(current) && !freezing(current) &&
185 !klp_patch_pending(current))
186 clear_thread_flag(TIF_SIGPENDING);
189 EXPORT_SYMBOL(recalc_sigpending);
191 void calculate_sigpending(void)
193 /* Have any signals or users of TIF_SIGPENDING been delayed
196 spin_lock_irq(¤t->sighand->siglock);
197 set_tsk_thread_flag(current, TIF_SIGPENDING);
199 spin_unlock_irq(¤t->sighand->siglock);
202 /* Given the mask, find the first available signal that should be serviced. */
204 #define SYNCHRONOUS_MASK \
205 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
206 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
208 int next_signal(struct sigpending *pending, sigset_t *mask)
210 unsigned long i, *s, *m, x;
213 s = pending->signal.sig;
217 * Handle the first word specially: it contains the
218 * synchronous signals that need to be dequeued first.
222 if (x & SYNCHRONOUS_MASK)
223 x &= SYNCHRONOUS_MASK;
228 switch (_NSIG_WORDS) {
230 for (i = 1; i < _NSIG_WORDS; ++i) {
234 sig = ffz(~x) + i*_NSIG_BPW + 1;
243 sig = ffz(~x) + _NSIG_BPW + 1;
254 static inline void print_dropped_signal(int sig)
256 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
258 if (!print_fatal_signals)
261 if (!__ratelimit(&ratelimit_state))
264 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
265 current->comm, current->pid, sig);
269 * task_set_jobctl_pending - set jobctl pending bits
271 * @mask: pending bits to set
273 * Clear @mask from @task->jobctl. @mask must be subset of
274 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
275 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
276 * cleared. If @task is already being killed or exiting, this function
280 * Must be called with @task->sighand->siglock held.
283 * %true if @mask is set, %false if made noop because @task was dying.
285 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
287 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
288 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
289 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
291 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
294 if (mask & JOBCTL_STOP_SIGMASK)
295 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
297 task->jobctl |= mask;
302 * task_clear_jobctl_trapping - clear jobctl trapping bit
305 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
306 * Clear it and wake up the ptracer. Note that we don't need any further
307 * locking. @task->siglock guarantees that @task->parent points to the
311 * Must be called with @task->sighand->siglock held.
313 void task_clear_jobctl_trapping(struct task_struct *task)
315 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
316 task->jobctl &= ~JOBCTL_TRAPPING;
317 smp_mb(); /* advised by wake_up_bit() */
318 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
323 * task_clear_jobctl_pending - clear jobctl pending bits
325 * @mask: pending bits to clear
327 * Clear @mask from @task->jobctl. @mask must be subset of
328 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
329 * STOP bits are cleared together.
331 * If clearing of @mask leaves no stop or trap pending, this function calls
332 * task_clear_jobctl_trapping().
335 * Must be called with @task->sighand->siglock held.
337 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
339 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
341 if (mask & JOBCTL_STOP_PENDING)
342 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
344 task->jobctl &= ~mask;
346 if (!(task->jobctl & JOBCTL_PENDING_MASK))
347 task_clear_jobctl_trapping(task);
351 * task_participate_group_stop - participate in a group stop
352 * @task: task participating in a group stop
354 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
355 * Group stop states are cleared and the group stop count is consumed if
356 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
357 * stop, the appropriate `SIGNAL_*` flags are set.
360 * Must be called with @task->sighand->siglock held.
363 * %true if group stop completion should be notified to the parent, %false
366 static bool task_participate_group_stop(struct task_struct *task)
368 struct signal_struct *sig = task->signal;
369 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
371 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
373 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
378 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
379 sig->group_stop_count--;
382 * Tell the caller to notify completion iff we are entering into a
383 * fresh group stop. Read comment in do_signal_stop() for details.
385 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
386 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
392 void task_join_group_stop(struct task_struct *task)
394 unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
395 struct signal_struct *sig = current->signal;
397 if (sig->group_stop_count) {
398 sig->group_stop_count++;
399 mask |= JOBCTL_STOP_CONSUME;
400 } else if (!(sig->flags & SIGNAL_STOP_STOPPED))
403 /* Have the new thread join an on-going signal group stop */
404 task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
408 * allocate a new signal queue record
409 * - this may be called without locks if and only if t == current, otherwise an
410 * appropriate lock must be held to stop the target task from exiting
412 static struct sigqueue *
413 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
415 struct sigqueue *q = NULL;
416 struct user_struct *user;
420 * Protect access to @t credentials. This can go away when all
421 * callers hold rcu read lock.
423 * NOTE! A pending signal will hold on to the user refcount,
424 * and we get/put the refcount only when the sigpending count
425 * changes from/to zero.
428 user = __task_cred(t)->user;
429 sigpending = atomic_inc_return(&user->sigpending);
434 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
435 q = kmem_cache_alloc(sigqueue_cachep, flags);
437 print_dropped_signal(sig);
440 if (unlikely(q == NULL)) {
441 if (atomic_dec_and_test(&user->sigpending))
444 INIT_LIST_HEAD(&q->list);
452 static void __sigqueue_free(struct sigqueue *q)
454 if (q->flags & SIGQUEUE_PREALLOC)
456 if (atomic_dec_and_test(&q->user->sigpending))
458 kmem_cache_free(sigqueue_cachep, q);
461 void flush_sigqueue(struct sigpending *queue)
465 sigemptyset(&queue->signal);
466 while (!list_empty(&queue->list)) {
467 q = list_entry(queue->list.next, struct sigqueue , list);
468 list_del_init(&q->list);
474 * Flush all pending signals for this kthread.
476 void flush_signals(struct task_struct *t)
480 spin_lock_irqsave(&t->sighand->siglock, flags);
481 clear_tsk_thread_flag(t, TIF_SIGPENDING);
482 flush_sigqueue(&t->pending);
483 flush_sigqueue(&t->signal->shared_pending);
484 spin_unlock_irqrestore(&t->sighand->siglock, flags);
486 EXPORT_SYMBOL(flush_signals);
488 #ifdef CONFIG_POSIX_TIMERS
489 static void __flush_itimer_signals(struct sigpending *pending)
491 sigset_t signal, retain;
492 struct sigqueue *q, *n;
494 signal = pending->signal;
495 sigemptyset(&retain);
497 list_for_each_entry_safe(q, n, &pending->list, list) {
498 int sig = q->info.si_signo;
500 if (likely(q->info.si_code != SI_TIMER)) {
501 sigaddset(&retain, sig);
503 sigdelset(&signal, sig);
504 list_del_init(&q->list);
509 sigorsets(&pending->signal, &signal, &retain);
512 void flush_itimer_signals(void)
514 struct task_struct *tsk = current;
517 spin_lock_irqsave(&tsk->sighand->siglock, flags);
518 __flush_itimer_signals(&tsk->pending);
519 __flush_itimer_signals(&tsk->signal->shared_pending);
520 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
524 void ignore_signals(struct task_struct *t)
528 for (i = 0; i < _NSIG; ++i)
529 t->sighand->action[i].sa.sa_handler = SIG_IGN;
535 * Flush all handlers for a task.
539 flush_signal_handlers(struct task_struct *t, int force_default)
542 struct k_sigaction *ka = &t->sighand->action[0];
543 for (i = _NSIG ; i != 0 ; i--) {
544 if (force_default || ka->sa.sa_handler != SIG_IGN)
545 ka->sa.sa_handler = SIG_DFL;
547 #ifdef __ARCH_HAS_SA_RESTORER
548 ka->sa.sa_restorer = NULL;
550 sigemptyset(&ka->sa.sa_mask);
555 bool unhandled_signal(struct task_struct *tsk, int sig)
557 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
558 if (is_global_init(tsk))
561 if (handler != SIG_IGN && handler != SIG_DFL)
564 /* if ptraced, let the tracer determine */
568 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
571 struct sigqueue *q, *first = NULL;
574 * Collect the siginfo appropriate to this signal. Check if
575 * there is another siginfo for the same signal.
577 list_for_each_entry(q, &list->list, list) {
578 if (q->info.si_signo == sig) {
585 sigdelset(&list->signal, sig);
589 list_del_init(&first->list);
590 copy_siginfo(info, &first->info);
593 (first->flags & SIGQUEUE_PREALLOC) &&
594 (info->si_code == SI_TIMER) &&
595 (info->si_sys_private);
597 __sigqueue_free(first);
600 * Ok, it wasn't in the queue. This must be
601 * a fast-pathed signal or we must have been
602 * out of queue space. So zero out the info.
605 info->si_signo = sig;
607 info->si_code = SI_USER;
613 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
614 kernel_siginfo_t *info, bool *resched_timer)
616 int sig = next_signal(pending, mask);
619 collect_signal(sig, pending, info, resched_timer);
624 * Dequeue a signal and return the element to the caller, which is
625 * expected to free it.
627 * All callers have to hold the siglock.
629 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
631 bool resched_timer = false;
634 /* We only dequeue private signals from ourselves, we don't let
635 * signalfd steal them
637 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
639 signr = __dequeue_signal(&tsk->signal->shared_pending,
640 mask, info, &resched_timer);
641 #ifdef CONFIG_POSIX_TIMERS
645 * itimers are process shared and we restart periodic
646 * itimers in the signal delivery path to prevent DoS
647 * attacks in the high resolution timer case. This is
648 * compliant with the old way of self-restarting
649 * itimers, as the SIGALRM is a legacy signal and only
650 * queued once. Changing the restart behaviour to
651 * restart the timer in the signal dequeue path is
652 * reducing the timer noise on heavy loaded !highres
655 if (unlikely(signr == SIGALRM)) {
656 struct hrtimer *tmr = &tsk->signal->real_timer;
658 if (!hrtimer_is_queued(tmr) &&
659 tsk->signal->it_real_incr != 0) {
660 hrtimer_forward(tmr, tmr->base->get_time(),
661 tsk->signal->it_real_incr);
662 hrtimer_restart(tmr);
672 if (unlikely(sig_kernel_stop(signr))) {
674 * Set a marker that we have dequeued a stop signal. Our
675 * caller might release the siglock and then the pending
676 * stop signal it is about to process is no longer in the
677 * pending bitmasks, but must still be cleared by a SIGCONT
678 * (and overruled by a SIGKILL). So those cases clear this
679 * shared flag after we've set it. Note that this flag may
680 * remain set after the signal we return is ignored or
681 * handled. That doesn't matter because its only purpose
682 * is to alert stop-signal processing code when another
683 * processor has come along and cleared the flag.
685 current->jobctl |= JOBCTL_STOP_DEQUEUED;
687 #ifdef CONFIG_POSIX_TIMERS
690 * Release the siglock to ensure proper locking order
691 * of timer locks outside of siglocks. Note, we leave
692 * irqs disabled here, since the posix-timers code is
693 * about to disable them again anyway.
695 spin_unlock(&tsk->sighand->siglock);
696 posixtimer_rearm(info);
697 spin_lock(&tsk->sighand->siglock);
699 /* Don't expose the si_sys_private value to userspace */
700 info->si_sys_private = 0;
705 EXPORT_SYMBOL_GPL(dequeue_signal);
707 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
709 struct task_struct *tsk = current;
710 struct sigpending *pending = &tsk->pending;
711 struct sigqueue *q, *sync = NULL;
714 * Might a synchronous signal be in the queue?
716 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
720 * Return the first synchronous signal in the queue.
722 list_for_each_entry(q, &pending->list, list) {
723 /* Synchronous signals have a positive si_code */
724 if ((q->info.si_code > SI_USER) &&
725 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
733 * Check if there is another siginfo for the same signal.
735 list_for_each_entry_continue(q, &pending->list, list) {
736 if (q->info.si_signo == sync->info.si_signo)
740 sigdelset(&pending->signal, sync->info.si_signo);
743 list_del_init(&sync->list);
744 copy_siginfo(info, &sync->info);
745 __sigqueue_free(sync);
746 return info->si_signo;
750 * Tell a process that it has a new active signal..
752 * NOTE! we rely on the previous spin_lock to
753 * lock interrupts for us! We can only be called with
754 * "siglock" held, and the local interrupt must
755 * have been disabled when that got acquired!
757 * No need to set need_resched since signal event passing
758 * goes through ->blocked
760 void signal_wake_up_state(struct task_struct *t, unsigned int state)
762 set_tsk_thread_flag(t, TIF_SIGPENDING);
764 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
765 * case. We don't check t->state here because there is a race with it
766 * executing another processor and just now entering stopped state.
767 * By using wake_up_state, we ensure the process will wake up and
768 * handle its death signal.
770 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
775 * Remove signals in mask from the pending set and queue.
776 * Returns 1 if any signals were found.
778 * All callers must be holding the siglock.
780 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
782 struct sigqueue *q, *n;
785 sigandsets(&m, mask, &s->signal);
786 if (sigisemptyset(&m))
789 sigandnsets(&s->signal, &s->signal, mask);
790 list_for_each_entry_safe(q, n, &s->list, list) {
791 if (sigismember(mask, q->info.si_signo)) {
792 list_del_init(&q->list);
798 static inline int is_si_special(const struct kernel_siginfo *info)
800 return info <= SEND_SIG_PRIV;
803 static inline bool si_fromuser(const struct kernel_siginfo *info)
805 return info == SEND_SIG_NOINFO ||
806 (!is_si_special(info) && SI_FROMUSER(info));
810 * called with RCU read lock from check_kill_permission()
812 static bool kill_ok_by_cred(struct task_struct *t)
814 const struct cred *cred = current_cred();
815 const struct cred *tcred = __task_cred(t);
817 return uid_eq(cred->euid, tcred->suid) ||
818 uid_eq(cred->euid, tcred->uid) ||
819 uid_eq(cred->uid, tcred->suid) ||
820 uid_eq(cred->uid, tcred->uid) ||
821 ns_capable(tcred->user_ns, CAP_KILL);
825 * Bad permissions for sending the signal
826 * - the caller must hold the RCU read lock
828 static int check_kill_permission(int sig, struct kernel_siginfo *info,
829 struct task_struct *t)
834 if (!valid_signal(sig))
837 if (!si_fromuser(info))
840 error = audit_signal_info(sig, t); /* Let audit system see the signal */
844 if (!same_thread_group(current, t) &&
845 !kill_ok_by_cred(t)) {
848 sid = task_session(t);
850 * We don't return the error if sid == NULL. The
851 * task was unhashed, the caller must notice this.
853 if (!sid || sid == task_session(current))
861 return security_task_kill(t, info, sig, NULL);
865 * ptrace_trap_notify - schedule trap to notify ptracer
866 * @t: tracee wanting to notify tracer
868 * This function schedules sticky ptrace trap which is cleared on the next
869 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
872 * If @t is running, STOP trap will be taken. If trapped for STOP and
873 * ptracer is listening for events, tracee is woken up so that it can
874 * re-trap for the new event. If trapped otherwise, STOP trap will be
875 * eventually taken without returning to userland after the existing traps
876 * are finished by PTRACE_CONT.
879 * Must be called with @task->sighand->siglock held.
881 static void ptrace_trap_notify(struct task_struct *t)
883 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
884 assert_spin_locked(&t->sighand->siglock);
886 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
887 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
891 * Handle magic process-wide effects of stop/continue signals. Unlike
892 * the signal actions, these happen immediately at signal-generation
893 * time regardless of blocking, ignoring, or handling. This does the
894 * actual continuing for SIGCONT, but not the actual stopping for stop
895 * signals. The process stop is done as a signal action for SIG_DFL.
897 * Returns true if the signal should be actually delivered, otherwise
898 * it should be dropped.
900 static bool prepare_signal(int sig, struct task_struct *p, bool force)
902 struct signal_struct *signal = p->signal;
903 struct task_struct *t;
906 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
907 if (!(signal->flags & SIGNAL_GROUP_EXIT))
908 return sig == SIGKILL;
910 * The process is in the middle of dying, nothing to do.
912 } else if (sig_kernel_stop(sig)) {
914 * This is a stop signal. Remove SIGCONT from all queues.
916 siginitset(&flush, sigmask(SIGCONT));
917 flush_sigqueue_mask(&flush, &signal->shared_pending);
918 for_each_thread(p, t)
919 flush_sigqueue_mask(&flush, &t->pending);
920 } else if (sig == SIGCONT) {
923 * Remove all stop signals from all queues, wake all threads.
925 siginitset(&flush, SIG_KERNEL_STOP_MASK);
926 flush_sigqueue_mask(&flush, &signal->shared_pending);
927 for_each_thread(p, t) {
928 flush_sigqueue_mask(&flush, &t->pending);
929 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
930 if (likely(!(t->ptrace & PT_SEIZED)))
931 wake_up_state(t, __TASK_STOPPED);
933 ptrace_trap_notify(t);
937 * Notify the parent with CLD_CONTINUED if we were stopped.
939 * If we were in the middle of a group stop, we pretend it
940 * was already finished, and then continued. Since SIGCHLD
941 * doesn't queue we report only CLD_STOPPED, as if the next
942 * CLD_CONTINUED was dropped.
945 if (signal->flags & SIGNAL_STOP_STOPPED)
946 why |= SIGNAL_CLD_CONTINUED;
947 else if (signal->group_stop_count)
948 why |= SIGNAL_CLD_STOPPED;
952 * The first thread which returns from do_signal_stop()
953 * will take ->siglock, notice SIGNAL_CLD_MASK, and
954 * notify its parent. See get_signal().
956 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
957 signal->group_stop_count = 0;
958 signal->group_exit_code = 0;
962 return !sig_ignored(p, sig, force);
966 * Test if P wants to take SIG. After we've checked all threads with this,
967 * it's equivalent to finding no threads not blocking SIG. Any threads not
968 * blocking SIG were ruled out because they are not running and already
969 * have pending signals. Such threads will dequeue from the shared queue
970 * as soon as they're available, so putting the signal on the shared queue
971 * will be equivalent to sending it to one such thread.
973 static inline bool wants_signal(int sig, struct task_struct *p)
975 if (sigismember(&p->blocked, sig))
978 if (p->flags & PF_EXITING)
984 if (task_is_stopped_or_traced(p))
987 return task_curr(p) || !signal_pending(p);
990 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
992 struct signal_struct *signal = p->signal;
993 struct task_struct *t;
996 * Now find a thread we can wake up to take the signal off the queue.
998 * If the main thread wants the signal, it gets first crack.
999 * Probably the least surprising to the average bear.
1001 if (wants_signal(sig, p))
1003 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1005 * There is just one thread and it does not need to be woken.
1006 * It will dequeue unblocked signals before it runs again.
1011 * Otherwise try to find a suitable thread.
1013 t = signal->curr_target;
1014 while (!wants_signal(sig, t)) {
1016 if (t == signal->curr_target)
1018 * No thread needs to be woken.
1019 * Any eligible threads will see
1020 * the signal in the queue soon.
1024 signal->curr_target = t;
1028 * Found a killable thread. If the signal will be fatal,
1029 * then start taking the whole group down immediately.
1031 if (sig_fatal(p, sig) &&
1032 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1033 !sigismember(&t->real_blocked, sig) &&
1034 (sig == SIGKILL || !p->ptrace)) {
1036 * This signal will be fatal to the whole group.
1038 if (!sig_kernel_coredump(sig)) {
1040 * Start a group exit and wake everybody up.
1041 * This way we don't have other threads
1042 * running and doing things after a slower
1043 * thread has the fatal signal pending.
1045 signal->flags = SIGNAL_GROUP_EXIT;
1046 signal->group_exit_code = sig;
1047 signal->group_stop_count = 0;
1050 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1051 sigaddset(&t->pending.signal, SIGKILL);
1052 signal_wake_up(t, 1);
1053 } while_each_thread(p, t);
1059 * The signal is already in the shared-pending queue.
1060 * Tell the chosen thread to wake up and dequeue it.
1062 signal_wake_up(t, sig == SIGKILL);
1066 static inline bool legacy_queue(struct sigpending *signals, int sig)
1068 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1071 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1072 enum pid_type type, bool force)
1074 struct sigpending *pending;
1076 int override_rlimit;
1077 int ret = 0, result;
1079 assert_spin_locked(&t->sighand->siglock);
1081 result = TRACE_SIGNAL_IGNORED;
1082 if (!prepare_signal(sig, t, force))
1085 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1087 * Short-circuit ignored signals and support queuing
1088 * exactly one non-rt signal, so that we can get more
1089 * detailed information about the cause of the signal.
1091 result = TRACE_SIGNAL_ALREADY_PENDING;
1092 if (legacy_queue(pending, sig))
1095 result = TRACE_SIGNAL_DELIVERED;
1097 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1099 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1103 * Real-time signals must be queued if sent by sigqueue, or
1104 * some other real-time mechanism. It is implementation
1105 * defined whether kill() does so. We attempt to do so, on
1106 * the principle of least surprise, but since kill is not
1107 * allowed to fail with EAGAIN when low on memory we just
1108 * make sure at least one signal gets delivered and don't
1109 * pass on the info struct.
1112 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1114 override_rlimit = 0;
1116 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
1118 list_add_tail(&q->list, &pending->list);
1119 switch ((unsigned long) info) {
1120 case (unsigned long) SEND_SIG_NOINFO:
1121 clear_siginfo(&q->info);
1122 q->info.si_signo = sig;
1123 q->info.si_errno = 0;
1124 q->info.si_code = SI_USER;
1125 q->info.si_pid = task_tgid_nr_ns(current,
1126 task_active_pid_ns(t));
1129 from_kuid_munged(task_cred_xxx(t, user_ns),
1133 case (unsigned long) SEND_SIG_PRIV:
1134 clear_siginfo(&q->info);
1135 q->info.si_signo = sig;
1136 q->info.si_errno = 0;
1137 q->info.si_code = SI_KERNEL;
1142 copy_siginfo(&q->info, info);
1145 } else if (!is_si_special(info) &&
1146 sig >= SIGRTMIN && info->si_code != SI_USER) {
1148 * Queue overflow, abort. We may abort if the
1149 * signal was rt and sent by user using something
1150 * other than kill().
1152 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1157 * This is a silent loss of information. We still
1158 * send the signal, but the *info bits are lost.
1160 result = TRACE_SIGNAL_LOSE_INFO;
1164 signalfd_notify(t, sig);
1165 sigaddset(&pending->signal, sig);
1167 /* Let multiprocess signals appear after on-going forks */
1168 if (type > PIDTYPE_TGID) {
1169 struct multiprocess_signals *delayed;
1170 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1171 sigset_t *signal = &delayed->signal;
1172 /* Can't queue both a stop and a continue signal */
1174 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1175 else if (sig_kernel_stop(sig))
1176 sigdelset(signal, SIGCONT);
1177 sigaddset(signal, sig);
1181 complete_signal(sig, t, type);
1183 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1187 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1190 switch (siginfo_layout(info->si_signo, info->si_code)) {
1199 case SIL_FAULT_MCEERR:
1200 case SIL_FAULT_BNDERR:
1201 case SIL_FAULT_PKUERR:
1209 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1212 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1215 if (info == SEND_SIG_NOINFO) {
1216 /* Force if sent from an ancestor pid namespace */
1217 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1218 } else if (info == SEND_SIG_PRIV) {
1219 /* Don't ignore kernel generated signals */
1221 } else if (has_si_pid_and_uid(info)) {
1222 /* SIGKILL and SIGSTOP is special or has ids */
1223 struct user_namespace *t_user_ns;
1226 t_user_ns = task_cred_xxx(t, user_ns);
1227 if (current_user_ns() != t_user_ns) {
1228 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1229 info->si_uid = from_kuid_munged(t_user_ns, uid);
1233 /* A kernel generated signal? */
1234 force = (info->si_code == SI_KERNEL);
1236 /* From an ancestor pid namespace? */
1237 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1242 return __send_signal(sig, info, t, type, force);
1245 static void print_fatal_signal(int signr)
1247 struct pt_regs *regs = signal_pt_regs();
1248 pr_info("potentially unexpected fatal signal %d.\n", signr);
1250 #if defined(__i386__) && !defined(__arch_um__)
1251 pr_info("code at %08lx: ", regs->ip);
1254 for (i = 0; i < 16; i++) {
1257 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1259 pr_cont("%02x ", insn);
1269 static int __init setup_print_fatal_signals(char *str)
1271 get_option (&str, &print_fatal_signals);
1276 __setup("print-fatal-signals=", setup_print_fatal_signals);
1279 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1281 return send_signal(sig, info, p, PIDTYPE_TGID);
1284 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1287 unsigned long flags;
1290 if (lock_task_sighand(p, &flags)) {
1291 ret = send_signal(sig, info, p, type);
1292 unlock_task_sighand(p, &flags);
1299 * Force a signal that the process can't ignore: if necessary
1300 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1302 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1303 * since we do not want to have a signal handler that was blocked
1304 * be invoked when user space had explicitly blocked it.
1306 * We don't want to have recursive SIGSEGV's etc, for example,
1307 * that is why we also clear SIGNAL_UNKILLABLE.
1310 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t)
1312 unsigned long int flags;
1313 int ret, blocked, ignored;
1314 struct k_sigaction *action;
1315 int sig = info->si_signo;
1317 spin_lock_irqsave(&t->sighand->siglock, flags);
1318 action = &t->sighand->action[sig-1];
1319 ignored = action->sa.sa_handler == SIG_IGN;
1320 blocked = sigismember(&t->blocked, sig);
1321 if (blocked || ignored) {
1322 action->sa.sa_handler = SIG_DFL;
1324 sigdelset(&t->blocked, sig);
1325 recalc_sigpending_and_wake(t);
1329 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1330 * debugging to leave init killable.
1332 if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
1333 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1334 ret = send_signal(sig, info, t, PIDTYPE_PID);
1335 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1340 int force_sig_info(struct kernel_siginfo *info)
1342 return force_sig_info_to_task(info, current);
1346 * Nuke all other threads in the group.
1348 int zap_other_threads(struct task_struct *p)
1350 struct task_struct *t = p;
1353 p->signal->group_stop_count = 0;
1355 while_each_thread(p, t) {
1356 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1359 /* Don't bother with already dead threads */
1362 sigaddset(&t->pending.signal, SIGKILL);
1363 signal_wake_up(t, 1);
1369 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1370 unsigned long *flags)
1372 struct sighand_struct *sighand;
1376 sighand = rcu_dereference(tsk->sighand);
1377 if (unlikely(sighand == NULL))
1381 * This sighand can be already freed and even reused, but
1382 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1383 * initializes ->siglock: this slab can't go away, it has
1384 * the same object type, ->siglock can't be reinitialized.
1386 * We need to ensure that tsk->sighand is still the same
1387 * after we take the lock, we can race with de_thread() or
1388 * __exit_signal(). In the latter case the next iteration
1389 * must see ->sighand == NULL.
1391 spin_lock_irqsave(&sighand->siglock, *flags);
1392 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1394 spin_unlock_irqrestore(&sighand->siglock, *flags);
1402 * send signal info to all the members of a group
1404 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1405 struct task_struct *p, enum pid_type type)
1410 ret = check_kill_permission(sig, info, p);
1414 ret = do_send_sig_info(sig, info, p, type);
1420 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1421 * control characters do (^C, ^Z etc)
1422 * - the caller must hold at least a readlock on tasklist_lock
1424 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1426 struct task_struct *p = NULL;
1427 int retval, success;
1431 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1432 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1435 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1436 return success ? 0 : retval;
1439 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1442 struct task_struct *p;
1446 p = pid_task(pid, PIDTYPE_PID);
1448 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1450 if (likely(!p || error != -ESRCH))
1454 * The task was unhashed in between, try again. If it
1455 * is dead, pid_task() will return NULL, if we race with
1456 * de_thread() it will find the new leader.
1461 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1465 error = kill_pid_info(sig, info, find_vpid(pid));
1470 static inline bool kill_as_cred_perm(const struct cred *cred,
1471 struct task_struct *target)
1473 const struct cred *pcred = __task_cred(target);
1475 return uid_eq(cred->euid, pcred->suid) ||
1476 uid_eq(cred->euid, pcred->uid) ||
1477 uid_eq(cred->uid, pcred->suid) ||
1478 uid_eq(cred->uid, pcred->uid);
1482 * The usb asyncio usage of siginfo is wrong. The glibc support
1483 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1484 * AKA after the generic fields:
1485 * kernel_pid_t si_pid;
1486 * kernel_uid32_t si_uid;
1487 * sigval_t si_value;
1489 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1490 * after the generic fields is:
1491 * void __user *si_addr;
1493 * This is a practical problem when there is a 64bit big endian kernel
1494 * and a 32bit userspace. As the 32bit address will encoded in the low
1495 * 32bits of the pointer. Those low 32bits will be stored at higher
1496 * address than appear in a 32 bit pointer. So userspace will not
1497 * see the address it was expecting for it's completions.
1499 * There is nothing in the encoding that can allow
1500 * copy_siginfo_to_user32 to detect this confusion of formats, so
1501 * handle this by requiring the caller of kill_pid_usb_asyncio to
1502 * notice when this situration takes place and to store the 32bit
1503 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1506 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1507 struct pid *pid, const struct cred *cred)
1509 struct kernel_siginfo info;
1510 struct task_struct *p;
1511 unsigned long flags;
1514 if (!valid_signal(sig))
1517 clear_siginfo(&info);
1518 info.si_signo = sig;
1519 info.si_errno = errno;
1520 info.si_code = SI_ASYNCIO;
1521 *((sigval_t *)&info.si_pid) = addr;
1524 p = pid_task(pid, PIDTYPE_PID);
1529 if (!kill_as_cred_perm(cred, p)) {
1533 ret = security_task_kill(p, &info, sig, cred);
1538 if (lock_task_sighand(p, &flags)) {
1539 ret = __send_signal(sig, &info, p, PIDTYPE_TGID, false);
1540 unlock_task_sighand(p, &flags);
1548 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1551 * kill_something_info() interprets pid in interesting ways just like kill(2).
1553 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1554 * is probably wrong. Should make it like BSD or SYSV.
1557 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1562 return kill_proc_info(sig, info, pid);
1564 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1568 read_lock(&tasklist_lock);
1570 ret = __kill_pgrp_info(sig, info,
1571 pid ? find_vpid(-pid) : task_pgrp(current));
1573 int retval = 0, count = 0;
1574 struct task_struct * p;
1576 for_each_process(p) {
1577 if (task_pid_vnr(p) > 1 &&
1578 !same_thread_group(p, current)) {
1579 int err = group_send_sig_info(sig, info, p,
1586 ret = count ? retval : -ESRCH;
1588 read_unlock(&tasklist_lock);
1594 * These are for backward compatibility with the rest of the kernel source.
1597 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1600 * Make sure legacy kernel users don't send in bad values
1601 * (normal paths check this in check_kill_permission).
1603 if (!valid_signal(sig))
1606 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1608 EXPORT_SYMBOL(send_sig_info);
1610 #define __si_special(priv) \
1611 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1614 send_sig(int sig, struct task_struct *p, int priv)
1616 return send_sig_info(sig, __si_special(priv), p);
1618 EXPORT_SYMBOL(send_sig);
1620 void force_sig(int sig)
1622 struct kernel_siginfo info;
1624 clear_siginfo(&info);
1625 info.si_signo = sig;
1627 info.si_code = SI_KERNEL;
1630 force_sig_info(&info);
1632 EXPORT_SYMBOL(force_sig);
1635 * When things go south during signal handling, we
1636 * will force a SIGSEGV. And if the signal that caused
1637 * the problem was already a SIGSEGV, we'll want to
1638 * make sure we don't even try to deliver the signal..
1640 void force_sigsegv(int sig)
1642 struct task_struct *p = current;
1644 if (sig == SIGSEGV) {
1645 unsigned long flags;
1646 spin_lock_irqsave(&p->sighand->siglock, flags);
1647 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1648 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1653 int force_sig_fault_to_task(int sig, int code, void __user *addr
1654 ___ARCH_SI_TRAPNO(int trapno)
1655 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1656 , struct task_struct *t)
1658 struct kernel_siginfo info;
1660 clear_siginfo(&info);
1661 info.si_signo = sig;
1663 info.si_code = code;
1664 info.si_addr = addr;
1665 #ifdef __ARCH_SI_TRAPNO
1666 info.si_trapno = trapno;
1670 info.si_flags = flags;
1673 return force_sig_info_to_task(&info, t);
1676 int force_sig_fault(int sig, int code, void __user *addr
1677 ___ARCH_SI_TRAPNO(int trapno)
1678 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1680 return force_sig_fault_to_task(sig, code, addr
1681 ___ARCH_SI_TRAPNO(trapno)
1682 ___ARCH_SI_IA64(imm, flags, isr), current);
1685 int send_sig_fault(int sig, int code, void __user *addr
1686 ___ARCH_SI_TRAPNO(int trapno)
1687 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1688 , struct task_struct *t)
1690 struct kernel_siginfo info;
1692 clear_siginfo(&info);
1693 info.si_signo = sig;
1695 info.si_code = code;
1696 info.si_addr = addr;
1697 #ifdef __ARCH_SI_TRAPNO
1698 info.si_trapno = trapno;
1702 info.si_flags = flags;
1705 return send_sig_info(info.si_signo, &info, t);
1708 int force_sig_mceerr(int code, void __user *addr, short lsb)
1710 struct kernel_siginfo info;
1712 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1713 clear_siginfo(&info);
1714 info.si_signo = SIGBUS;
1716 info.si_code = code;
1717 info.si_addr = addr;
1718 info.si_addr_lsb = lsb;
1719 return force_sig_info(&info);
1722 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1724 struct kernel_siginfo info;
1726 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1727 clear_siginfo(&info);
1728 info.si_signo = SIGBUS;
1730 info.si_code = code;
1731 info.si_addr = addr;
1732 info.si_addr_lsb = lsb;
1733 return send_sig_info(info.si_signo, &info, t);
1735 EXPORT_SYMBOL(send_sig_mceerr);
1737 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1739 struct kernel_siginfo info;
1741 clear_siginfo(&info);
1742 info.si_signo = SIGSEGV;
1744 info.si_code = SEGV_BNDERR;
1745 info.si_addr = addr;
1746 info.si_lower = lower;
1747 info.si_upper = upper;
1748 return force_sig_info(&info);
1752 int force_sig_pkuerr(void __user *addr, u32 pkey)
1754 struct kernel_siginfo info;
1756 clear_siginfo(&info);
1757 info.si_signo = SIGSEGV;
1759 info.si_code = SEGV_PKUERR;
1760 info.si_addr = addr;
1761 info.si_pkey = pkey;
1762 return force_sig_info(&info);
1766 /* For the crazy architectures that include trap information in
1767 * the errno field, instead of an actual errno value.
1769 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1771 struct kernel_siginfo info;
1773 clear_siginfo(&info);
1774 info.si_signo = SIGTRAP;
1775 info.si_errno = errno;
1776 info.si_code = TRAP_HWBKPT;
1777 info.si_addr = addr;
1778 return force_sig_info(&info);
1781 int kill_pgrp(struct pid *pid, int sig, int priv)
1785 read_lock(&tasklist_lock);
1786 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1787 read_unlock(&tasklist_lock);
1791 EXPORT_SYMBOL(kill_pgrp);
1793 int kill_pid(struct pid *pid, int sig, int priv)
1795 return kill_pid_info(sig, __si_special(priv), pid);
1797 EXPORT_SYMBOL(kill_pid);
1800 * These functions support sending signals using preallocated sigqueue
1801 * structures. This is needed "because realtime applications cannot
1802 * afford to lose notifications of asynchronous events, like timer
1803 * expirations or I/O completions". In the case of POSIX Timers
1804 * we allocate the sigqueue structure from the timer_create. If this
1805 * allocation fails we are able to report the failure to the application
1806 * with an EAGAIN error.
1808 struct sigqueue *sigqueue_alloc(void)
1810 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1813 q->flags |= SIGQUEUE_PREALLOC;
1818 void sigqueue_free(struct sigqueue *q)
1820 unsigned long flags;
1821 spinlock_t *lock = ¤t->sighand->siglock;
1823 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1825 * We must hold ->siglock while testing q->list
1826 * to serialize with collect_signal() or with
1827 * __exit_signal()->flush_sigqueue().
1829 spin_lock_irqsave(lock, flags);
1830 q->flags &= ~SIGQUEUE_PREALLOC;
1832 * If it is queued it will be freed when dequeued,
1833 * like the "regular" sigqueue.
1835 if (!list_empty(&q->list))
1837 spin_unlock_irqrestore(lock, flags);
1843 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1845 int sig = q->info.si_signo;
1846 struct sigpending *pending;
1847 struct task_struct *t;
1848 unsigned long flags;
1851 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1855 t = pid_task(pid, type);
1856 if (!t || !likely(lock_task_sighand(t, &flags)))
1859 ret = 1; /* the signal is ignored */
1860 result = TRACE_SIGNAL_IGNORED;
1861 if (!prepare_signal(sig, t, false))
1865 if (unlikely(!list_empty(&q->list))) {
1867 * If an SI_TIMER entry is already queue just increment
1868 * the overrun count.
1870 BUG_ON(q->info.si_code != SI_TIMER);
1871 q->info.si_overrun++;
1872 result = TRACE_SIGNAL_ALREADY_PENDING;
1875 q->info.si_overrun = 0;
1877 signalfd_notify(t, sig);
1878 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1879 list_add_tail(&q->list, &pending->list);
1880 sigaddset(&pending->signal, sig);
1881 complete_signal(sig, t, type);
1882 result = TRACE_SIGNAL_DELIVERED;
1884 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
1885 unlock_task_sighand(t, &flags);
1891 static void do_notify_pidfd(struct task_struct *task)
1895 WARN_ON(task->exit_state == 0);
1896 pid = task_pid(task);
1897 wake_up_all(&pid->wait_pidfd);
1901 * Let a parent know about the death of a child.
1902 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1904 * Returns true if our parent ignored us and so we've switched to
1907 bool do_notify_parent(struct task_struct *tsk, int sig)
1909 struct kernel_siginfo info;
1910 unsigned long flags;
1911 struct sighand_struct *psig;
1912 bool autoreap = false;
1917 /* do_notify_parent_cldstop should have been called instead. */
1918 BUG_ON(task_is_stopped_or_traced(tsk));
1920 BUG_ON(!tsk->ptrace &&
1921 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1923 /* Wake up all pidfd waiters */
1924 do_notify_pidfd(tsk);
1926 if (sig != SIGCHLD) {
1928 * This is only possible if parent == real_parent.
1929 * Check if it has changed security domain.
1931 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
1935 clear_siginfo(&info);
1936 info.si_signo = sig;
1939 * We are under tasklist_lock here so our parent is tied to
1940 * us and cannot change.
1942 * task_active_pid_ns will always return the same pid namespace
1943 * until a task passes through release_task.
1945 * write_lock() currently calls preempt_disable() which is the
1946 * same as rcu_read_lock(), but according to Oleg, this is not
1947 * correct to rely on this
1950 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1951 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1955 task_cputime(tsk, &utime, &stime);
1956 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
1957 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
1959 info.si_status = tsk->exit_code & 0x7f;
1960 if (tsk->exit_code & 0x80)
1961 info.si_code = CLD_DUMPED;
1962 else if (tsk->exit_code & 0x7f)
1963 info.si_code = CLD_KILLED;
1965 info.si_code = CLD_EXITED;
1966 info.si_status = tsk->exit_code >> 8;
1969 psig = tsk->parent->sighand;
1970 spin_lock_irqsave(&psig->siglock, flags);
1971 if (!tsk->ptrace && sig == SIGCHLD &&
1972 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1973 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1975 * We are exiting and our parent doesn't care. POSIX.1
1976 * defines special semantics for setting SIGCHLD to SIG_IGN
1977 * or setting the SA_NOCLDWAIT flag: we should be reaped
1978 * automatically and not left for our parent's wait4 call.
1979 * Rather than having the parent do it as a magic kind of
1980 * signal handler, we just set this to tell do_exit that we
1981 * can be cleaned up without becoming a zombie. Note that
1982 * we still call __wake_up_parent in this case, because a
1983 * blocked sys_wait4 might now return -ECHILD.
1985 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1986 * is implementation-defined: we do (if you don't want
1987 * it, just use SIG_IGN instead).
1990 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1994 * Send with __send_signal as si_pid and si_uid are in the
1995 * parent's namespaces.
1997 if (valid_signal(sig) && sig)
1998 __send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false);
1999 __wake_up_parent(tsk, tsk->parent);
2000 spin_unlock_irqrestore(&psig->siglock, flags);
2006 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2007 * @tsk: task reporting the state change
2008 * @for_ptracer: the notification is for ptracer
2009 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2011 * Notify @tsk's parent that the stopped/continued state has changed. If
2012 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2013 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2016 * Must be called with tasklist_lock at least read locked.
2018 static void do_notify_parent_cldstop(struct task_struct *tsk,
2019 bool for_ptracer, int why)
2021 struct kernel_siginfo info;
2022 unsigned long flags;
2023 struct task_struct *parent;
2024 struct sighand_struct *sighand;
2028 parent = tsk->parent;
2030 tsk = tsk->group_leader;
2031 parent = tsk->real_parent;
2034 clear_siginfo(&info);
2035 info.si_signo = SIGCHLD;
2038 * see comment in do_notify_parent() about the following 4 lines
2041 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2042 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2045 task_cputime(tsk, &utime, &stime);
2046 info.si_utime = nsec_to_clock_t(utime);
2047 info.si_stime = nsec_to_clock_t(stime);
2052 info.si_status = SIGCONT;
2055 info.si_status = tsk->signal->group_exit_code & 0x7f;
2058 info.si_status = tsk->exit_code & 0x7f;
2064 sighand = parent->sighand;
2065 spin_lock_irqsave(&sighand->siglock, flags);
2066 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2067 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2068 __group_send_sig_info(SIGCHLD, &info, parent);
2070 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2072 __wake_up_parent(tsk, parent);
2073 spin_unlock_irqrestore(&sighand->siglock, flags);
2076 static inline bool may_ptrace_stop(void)
2078 if (!likely(current->ptrace))
2081 * Are we in the middle of do_coredump?
2082 * If so and our tracer is also part of the coredump stopping
2083 * is a deadlock situation, and pointless because our tracer
2084 * is dead so don't allow us to stop.
2085 * If SIGKILL was already sent before the caller unlocked
2086 * ->siglock we must see ->core_state != NULL. Otherwise it
2087 * is safe to enter schedule().
2089 * This is almost outdated, a task with the pending SIGKILL can't
2090 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2091 * after SIGKILL was already dequeued.
2093 if (unlikely(current->mm->core_state) &&
2094 unlikely(current->mm == current->parent->mm))
2101 * Return non-zero if there is a SIGKILL that should be waking us up.
2102 * Called with the siglock held.
2104 static bool sigkill_pending(struct task_struct *tsk)
2106 return sigismember(&tsk->pending.signal, SIGKILL) ||
2107 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
2111 * This must be called with current->sighand->siglock held.
2113 * This should be the path for all ptrace stops.
2114 * We always set current->last_siginfo while stopped here.
2115 * That makes it a way to test a stopped process for
2116 * being ptrace-stopped vs being job-control-stopped.
2118 * If we actually decide not to stop at all because the tracer
2119 * is gone, we keep current->exit_code unless clear_code.
2121 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2122 __releases(¤t->sighand->siglock)
2123 __acquires(¤t->sighand->siglock)
2125 bool gstop_done = false;
2127 if (arch_ptrace_stop_needed(exit_code, info)) {
2129 * The arch code has something special to do before a
2130 * ptrace stop. This is allowed to block, e.g. for faults
2131 * on user stack pages. We can't keep the siglock while
2132 * calling arch_ptrace_stop, so we must release it now.
2133 * To preserve proper semantics, we must do this before
2134 * any signal bookkeeping like checking group_stop_count.
2135 * Meanwhile, a SIGKILL could come in before we retake the
2136 * siglock. That must prevent us from sleeping in TASK_TRACED.
2137 * So after regaining the lock, we must check for SIGKILL.
2139 spin_unlock_irq(¤t->sighand->siglock);
2140 arch_ptrace_stop(exit_code, info);
2141 spin_lock_irq(¤t->sighand->siglock);
2142 if (sigkill_pending(current))
2146 set_special_state(TASK_TRACED);
2149 * We're committing to trapping. TRACED should be visible before
2150 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2151 * Also, transition to TRACED and updates to ->jobctl should be
2152 * atomic with respect to siglock and should be done after the arch
2153 * hook as siglock is released and regrabbed across it.
2158 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2160 * set_current_state() smp_wmb();
2162 * wait_task_stopped()
2163 * task_stopped_code()
2164 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2168 current->last_siginfo = info;
2169 current->exit_code = exit_code;
2172 * If @why is CLD_STOPPED, we're trapping to participate in a group
2173 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2174 * across siglock relocks since INTERRUPT was scheduled, PENDING
2175 * could be clear now. We act as if SIGCONT is received after
2176 * TASK_TRACED is entered - ignore it.
2178 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2179 gstop_done = task_participate_group_stop(current);
2181 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2182 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2183 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2184 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2186 /* entering a trap, clear TRAPPING */
2187 task_clear_jobctl_trapping(current);
2189 spin_unlock_irq(¤t->sighand->siglock);
2190 read_lock(&tasklist_lock);
2191 if (may_ptrace_stop()) {
2193 * Notify parents of the stop.
2195 * While ptraced, there are two parents - the ptracer and
2196 * the real_parent of the group_leader. The ptracer should
2197 * know about every stop while the real parent is only
2198 * interested in the completion of group stop. The states
2199 * for the two don't interact with each other. Notify
2200 * separately unless they're gonna be duplicates.
2202 do_notify_parent_cldstop(current, true, why);
2203 if (gstop_done && ptrace_reparented(current))
2204 do_notify_parent_cldstop(current, false, why);
2207 * Don't want to allow preemption here, because
2208 * sys_ptrace() needs this task to be inactive.
2210 * XXX: implement read_unlock_no_resched().
2213 read_unlock(&tasklist_lock);
2214 cgroup_enter_frozen();
2215 preempt_enable_no_resched();
2216 freezable_schedule();
2217 cgroup_leave_frozen(true);
2220 * By the time we got the lock, our tracer went away.
2221 * Don't drop the lock yet, another tracer may come.
2223 * If @gstop_done, the ptracer went away between group stop
2224 * completion and here. During detach, it would have set
2225 * JOBCTL_STOP_PENDING on us and we'll re-enter
2226 * TASK_STOPPED in do_signal_stop() on return, so notifying
2227 * the real parent of the group stop completion is enough.
2230 do_notify_parent_cldstop(current, false, why);
2232 /* tasklist protects us from ptrace_freeze_traced() */
2233 __set_current_state(TASK_RUNNING);
2235 current->exit_code = 0;
2236 read_unlock(&tasklist_lock);
2240 * We are back. Now reacquire the siglock before touching
2241 * last_siginfo, so that we are sure to have synchronized with
2242 * any signal-sending on another CPU that wants to examine it.
2244 spin_lock_irq(¤t->sighand->siglock);
2245 current->last_siginfo = NULL;
2247 /* LISTENING can be set only during STOP traps, clear it */
2248 current->jobctl &= ~JOBCTL_LISTENING;
2251 * Queued signals ignored us while we were stopped for tracing.
2252 * So check for any that we should take before resuming user mode.
2253 * This sets TIF_SIGPENDING, but never clears it.
2255 recalc_sigpending_tsk(current);
2258 static void ptrace_do_notify(int signr, int exit_code, int why)
2260 kernel_siginfo_t info;
2262 clear_siginfo(&info);
2263 info.si_signo = signr;
2264 info.si_code = exit_code;
2265 info.si_pid = task_pid_vnr(current);
2266 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2268 /* Let the debugger run. */
2269 ptrace_stop(exit_code, why, 1, &info);
2272 void ptrace_notify(int exit_code)
2274 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2275 if (unlikely(current->task_works))
2278 spin_lock_irq(¤t->sighand->siglock);
2279 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2280 spin_unlock_irq(¤t->sighand->siglock);
2284 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2285 * @signr: signr causing group stop if initiating
2287 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2288 * and participate in it. If already set, participate in the existing
2289 * group stop. If participated in a group stop (and thus slept), %true is
2290 * returned with siglock released.
2292 * If ptraced, this function doesn't handle stop itself. Instead,
2293 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2294 * untouched. The caller must ensure that INTERRUPT trap handling takes
2295 * places afterwards.
2298 * Must be called with @current->sighand->siglock held, which is released
2302 * %false if group stop is already cancelled or ptrace trap is scheduled.
2303 * %true if participated in group stop.
2305 static bool do_signal_stop(int signr)
2306 __releases(¤t->sighand->siglock)
2308 struct signal_struct *sig = current->signal;
2310 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2311 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2312 struct task_struct *t;
2314 /* signr will be recorded in task->jobctl for retries */
2315 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2317 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2318 unlikely(signal_group_exit(sig)))
2321 * There is no group stop already in progress. We must
2324 * While ptraced, a task may be resumed while group stop is
2325 * still in effect and then receive a stop signal and
2326 * initiate another group stop. This deviates from the
2327 * usual behavior as two consecutive stop signals can't
2328 * cause two group stops when !ptraced. That is why we
2329 * also check !task_is_stopped(t) below.
2331 * The condition can be distinguished by testing whether
2332 * SIGNAL_STOP_STOPPED is already set. Don't generate
2333 * group_exit_code in such case.
2335 * This is not necessary for SIGNAL_STOP_CONTINUED because
2336 * an intervening stop signal is required to cause two
2337 * continued events regardless of ptrace.
2339 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2340 sig->group_exit_code = signr;
2342 sig->group_stop_count = 0;
2344 if (task_set_jobctl_pending(current, signr | gstop))
2345 sig->group_stop_count++;
2348 while_each_thread(current, t) {
2350 * Setting state to TASK_STOPPED for a group
2351 * stop is always done with the siglock held,
2352 * so this check has no races.
2354 if (!task_is_stopped(t) &&
2355 task_set_jobctl_pending(t, signr | gstop)) {
2356 sig->group_stop_count++;
2357 if (likely(!(t->ptrace & PT_SEIZED)))
2358 signal_wake_up(t, 0);
2360 ptrace_trap_notify(t);
2365 if (likely(!current->ptrace)) {
2369 * If there are no other threads in the group, or if there
2370 * is a group stop in progress and we are the last to stop,
2371 * report to the parent.
2373 if (task_participate_group_stop(current))
2374 notify = CLD_STOPPED;
2376 set_special_state(TASK_STOPPED);
2377 spin_unlock_irq(¤t->sighand->siglock);
2380 * Notify the parent of the group stop completion. Because
2381 * we're not holding either the siglock or tasklist_lock
2382 * here, ptracer may attach inbetween; however, this is for
2383 * group stop and should always be delivered to the real
2384 * parent of the group leader. The new ptracer will get
2385 * its notification when this task transitions into
2389 read_lock(&tasklist_lock);
2390 do_notify_parent_cldstop(current, false, notify);
2391 read_unlock(&tasklist_lock);
2394 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2395 cgroup_enter_frozen();
2396 freezable_schedule();
2400 * While ptraced, group stop is handled by STOP trap.
2401 * Schedule it and let the caller deal with it.
2403 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2409 * do_jobctl_trap - take care of ptrace jobctl traps
2411 * When PT_SEIZED, it's used for both group stop and explicit
2412 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2413 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2414 * the stop signal; otherwise, %SIGTRAP.
2416 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2417 * number as exit_code and no siginfo.
2420 * Must be called with @current->sighand->siglock held, which may be
2421 * released and re-acquired before returning with intervening sleep.
2423 static void do_jobctl_trap(void)
2425 struct signal_struct *signal = current->signal;
2426 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2428 if (current->ptrace & PT_SEIZED) {
2429 if (!signal->group_stop_count &&
2430 !(signal->flags & SIGNAL_STOP_STOPPED))
2432 WARN_ON_ONCE(!signr);
2433 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2436 WARN_ON_ONCE(!signr);
2437 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2438 current->exit_code = 0;
2443 * do_freezer_trap - handle the freezer jobctl trap
2445 * Puts the task into frozen state, if only the task is not about to quit.
2446 * In this case it drops JOBCTL_TRAP_FREEZE.
2449 * Must be called with @current->sighand->siglock held,
2450 * which is always released before returning.
2452 static void do_freezer_trap(void)
2453 __releases(¤t->sighand->siglock)
2456 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2457 * let's make another loop to give it a chance to be handled.
2458 * In any case, we'll return back.
2460 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2461 JOBCTL_TRAP_FREEZE) {
2462 spin_unlock_irq(¤t->sighand->siglock);
2467 * Now we're sure that there is no pending fatal signal and no
2468 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2469 * immediately (if there is a non-fatal signal pending), and
2470 * put the task into sleep.
2472 __set_current_state(TASK_INTERRUPTIBLE);
2473 clear_thread_flag(TIF_SIGPENDING);
2474 spin_unlock_irq(¤t->sighand->siglock);
2475 cgroup_enter_frozen();
2476 freezable_schedule();
2479 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2482 * We do not check sig_kernel_stop(signr) but set this marker
2483 * unconditionally because we do not know whether debugger will
2484 * change signr. This flag has no meaning unless we are going
2485 * to stop after return from ptrace_stop(). In this case it will
2486 * be checked in do_signal_stop(), we should only stop if it was
2487 * not cleared by SIGCONT while we were sleeping. See also the
2488 * comment in dequeue_signal().
2490 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2491 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2493 /* We're back. Did the debugger cancel the sig? */
2494 signr = current->exit_code;
2498 current->exit_code = 0;
2501 * Update the siginfo structure if the signal has
2502 * changed. If the debugger wanted something
2503 * specific in the siginfo structure then it should
2504 * have updated *info via PTRACE_SETSIGINFO.
2506 if (signr != info->si_signo) {
2507 clear_siginfo(info);
2508 info->si_signo = signr;
2510 info->si_code = SI_USER;
2512 info->si_pid = task_pid_vnr(current->parent);
2513 info->si_uid = from_kuid_munged(current_user_ns(),
2514 task_uid(current->parent));
2518 /* If the (new) signal is now blocked, requeue it. */
2519 if (sigismember(¤t->blocked, signr)) {
2520 send_signal(signr, info, current, PIDTYPE_PID);
2527 bool get_signal(struct ksignal *ksig)
2529 struct sighand_struct *sighand = current->sighand;
2530 struct signal_struct *signal = current->signal;
2533 if (unlikely(uprobe_deny_signal()))
2537 * Do this once, we can't return to user-mode if freezing() == T.
2538 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2539 * thus do not need another check after return.
2544 spin_lock_irq(&sighand->siglock);
2546 * Make sure we can safely read ->jobctl() in task_work add. As Oleg
2549 * It pairs with mb (implied by cmpxchg) before READ_ONCE. So we
2552 * task_work_add: get_signal:
2553 * STORE(task->task_works, new_work); STORE(task->jobctl);
2555 * LOAD(task->jobctl); LOAD(task->task_works);
2557 * and we can rely on STORE-MB-LOAD [ in task_work_add].
2559 smp_store_mb(current->jobctl, current->jobctl & ~JOBCTL_TASK_WORK);
2560 if (unlikely(current->task_works)) {
2561 spin_unlock_irq(&sighand->siglock);
2567 * Every stopped thread goes here after wakeup. Check to see if
2568 * we should notify the parent, prepare_signal(SIGCONT) encodes
2569 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2571 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2574 if (signal->flags & SIGNAL_CLD_CONTINUED)
2575 why = CLD_CONTINUED;
2579 signal->flags &= ~SIGNAL_CLD_MASK;
2581 spin_unlock_irq(&sighand->siglock);
2584 * Notify the parent that we're continuing. This event is
2585 * always per-process and doesn't make whole lot of sense
2586 * for ptracers, who shouldn't consume the state via
2587 * wait(2) either, but, for backward compatibility, notify
2588 * the ptracer of the group leader too unless it's gonna be
2591 read_lock(&tasklist_lock);
2592 do_notify_parent_cldstop(current, false, why);
2594 if (ptrace_reparented(current->group_leader))
2595 do_notify_parent_cldstop(current->group_leader,
2597 read_unlock(&tasklist_lock);
2602 /* Has this task already been marked for death? */
2603 if (signal_group_exit(signal)) {
2604 ksig->info.si_signo = signr = SIGKILL;
2605 sigdelset(¤t->pending.signal, SIGKILL);
2606 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2607 &sighand->action[SIGKILL - 1]);
2608 recalc_sigpending();
2613 struct k_sigaction *ka;
2615 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2619 if (unlikely(current->jobctl &
2620 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2621 if (current->jobctl & JOBCTL_TRAP_MASK) {
2623 spin_unlock_irq(&sighand->siglock);
2624 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2631 * If the task is leaving the frozen state, let's update
2632 * cgroup counters and reset the frozen bit.
2634 if (unlikely(cgroup_task_frozen(current))) {
2635 spin_unlock_irq(&sighand->siglock);
2636 cgroup_leave_frozen(false);
2641 * Signals generated by the execution of an instruction
2642 * need to be delivered before any other pending signals
2643 * so that the instruction pointer in the signal stack
2644 * frame points to the faulting instruction.
2646 signr = dequeue_synchronous_signal(&ksig->info);
2648 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2651 break; /* will return 0 */
2653 if (unlikely(current->ptrace) && signr != SIGKILL) {
2654 signr = ptrace_signal(signr, &ksig->info);
2659 ka = &sighand->action[signr-1];
2661 /* Trace actually delivered signals. */
2662 trace_signal_deliver(signr, &ksig->info, ka);
2664 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2666 if (ka->sa.sa_handler != SIG_DFL) {
2667 /* Run the handler. */
2670 if (ka->sa.sa_flags & SA_ONESHOT)
2671 ka->sa.sa_handler = SIG_DFL;
2673 break; /* will return non-zero "signr" value */
2677 * Now we are doing the default action for this signal.
2679 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2683 * Global init gets no signals it doesn't want.
2684 * Container-init gets no signals it doesn't want from same
2687 * Note that if global/container-init sees a sig_kernel_only()
2688 * signal here, the signal must have been generated internally
2689 * or must have come from an ancestor namespace. In either
2690 * case, the signal cannot be dropped.
2692 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2693 !sig_kernel_only(signr))
2696 if (sig_kernel_stop(signr)) {
2698 * The default action is to stop all threads in
2699 * the thread group. The job control signals
2700 * do nothing in an orphaned pgrp, but SIGSTOP
2701 * always works. Note that siglock needs to be
2702 * dropped during the call to is_orphaned_pgrp()
2703 * because of lock ordering with tasklist_lock.
2704 * This allows an intervening SIGCONT to be posted.
2705 * We need to check for that and bail out if necessary.
2707 if (signr != SIGSTOP) {
2708 spin_unlock_irq(&sighand->siglock);
2710 /* signals can be posted during this window */
2712 if (is_current_pgrp_orphaned())
2715 spin_lock_irq(&sighand->siglock);
2718 if (likely(do_signal_stop(ksig->info.si_signo))) {
2719 /* It released the siglock. */
2724 * We didn't actually stop, due to a race
2725 * with SIGCONT or something like that.
2731 spin_unlock_irq(&sighand->siglock);
2732 if (unlikely(cgroup_task_frozen(current)))
2733 cgroup_leave_frozen(true);
2736 * Anything else is fatal, maybe with a core dump.
2738 current->flags |= PF_SIGNALED;
2740 if (sig_kernel_coredump(signr)) {
2741 if (print_fatal_signals)
2742 print_fatal_signal(ksig->info.si_signo);
2743 proc_coredump_connector(current);
2745 * If it was able to dump core, this kills all
2746 * other threads in the group and synchronizes with
2747 * their demise. If we lost the race with another
2748 * thread getting here, it set group_exit_code
2749 * first and our do_group_exit call below will use
2750 * that value and ignore the one we pass it.
2752 do_coredump(&ksig->info);
2756 * Death signals, no core dump.
2758 do_group_exit(ksig->info.si_signo);
2761 spin_unlock_irq(&sighand->siglock);
2764 return ksig->sig > 0;
2768 * signal_delivered -
2769 * @ksig: kernel signal struct
2770 * @stepping: nonzero if debugger single-step or block-step in use
2772 * This function should be called when a signal has successfully been
2773 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2774 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2775 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2777 static void signal_delivered(struct ksignal *ksig, int stepping)
2781 /* A signal was successfully delivered, and the
2782 saved sigmask was stored on the signal frame,
2783 and will be restored by sigreturn. So we can
2784 simply clear the restore sigmask flag. */
2785 clear_restore_sigmask();
2787 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2788 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2789 sigaddset(&blocked, ksig->sig);
2790 set_current_blocked(&blocked);
2791 tracehook_signal_handler(stepping);
2794 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2797 force_sigsegv(ksig->sig);
2799 signal_delivered(ksig, stepping);
2803 * It could be that complete_signal() picked us to notify about the
2804 * group-wide signal. Other threads should be notified now to take
2805 * the shared signals in @which since we will not.
2807 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2810 struct task_struct *t;
2812 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2813 if (sigisemptyset(&retarget))
2817 while_each_thread(tsk, t) {
2818 if (t->flags & PF_EXITING)
2821 if (!has_pending_signals(&retarget, &t->blocked))
2823 /* Remove the signals this thread can handle. */
2824 sigandsets(&retarget, &retarget, &t->blocked);
2826 if (!signal_pending(t))
2827 signal_wake_up(t, 0);
2829 if (sigisemptyset(&retarget))
2834 void exit_signals(struct task_struct *tsk)
2840 * @tsk is about to have PF_EXITING set - lock out users which
2841 * expect stable threadgroup.
2843 cgroup_threadgroup_change_begin(tsk);
2845 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2846 tsk->flags |= PF_EXITING;
2847 cgroup_threadgroup_change_end(tsk);
2851 spin_lock_irq(&tsk->sighand->siglock);
2853 * From now this task is not visible for group-wide signals,
2854 * see wants_signal(), do_signal_stop().
2856 tsk->flags |= PF_EXITING;
2858 cgroup_threadgroup_change_end(tsk);
2860 if (!signal_pending(tsk))
2863 unblocked = tsk->blocked;
2864 signotset(&unblocked);
2865 retarget_shared_pending(tsk, &unblocked);
2867 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2868 task_participate_group_stop(tsk))
2869 group_stop = CLD_STOPPED;
2871 spin_unlock_irq(&tsk->sighand->siglock);
2874 * If group stop has completed, deliver the notification. This
2875 * should always go to the real parent of the group leader.
2877 if (unlikely(group_stop)) {
2878 read_lock(&tasklist_lock);
2879 do_notify_parent_cldstop(tsk, false, group_stop);
2880 read_unlock(&tasklist_lock);
2885 * System call entry points.
2889 * sys_restart_syscall - restart a system call
2891 SYSCALL_DEFINE0(restart_syscall)
2893 struct restart_block *restart = ¤t->restart_block;
2894 return restart->fn(restart);
2897 long do_no_restart_syscall(struct restart_block *param)
2902 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2904 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2905 sigset_t newblocked;
2906 /* A set of now blocked but previously unblocked signals. */
2907 sigandnsets(&newblocked, newset, ¤t->blocked);
2908 retarget_shared_pending(tsk, &newblocked);
2910 tsk->blocked = *newset;
2911 recalc_sigpending();
2915 * set_current_blocked - change current->blocked mask
2918 * It is wrong to change ->blocked directly, this helper should be used
2919 * to ensure the process can't miss a shared signal we are going to block.
2921 void set_current_blocked(sigset_t *newset)
2923 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2924 __set_current_blocked(newset);
2927 void __set_current_blocked(const sigset_t *newset)
2929 struct task_struct *tsk = current;
2932 * In case the signal mask hasn't changed, there is nothing we need
2933 * to do. The current->blocked shouldn't be modified by other task.
2935 if (sigequalsets(&tsk->blocked, newset))
2938 spin_lock_irq(&tsk->sighand->siglock);
2939 __set_task_blocked(tsk, newset);
2940 spin_unlock_irq(&tsk->sighand->siglock);
2944 * This is also useful for kernel threads that want to temporarily
2945 * (or permanently) block certain signals.
2947 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2948 * interface happily blocks "unblockable" signals like SIGKILL
2951 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2953 struct task_struct *tsk = current;
2956 /* Lockless, only current can change ->blocked, never from irq */
2958 *oldset = tsk->blocked;
2962 sigorsets(&newset, &tsk->blocked, set);
2965 sigandnsets(&newset, &tsk->blocked, set);
2974 __set_current_blocked(&newset);
2977 EXPORT_SYMBOL(sigprocmask);
2980 * The api helps set app-provided sigmasks.
2982 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2983 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
2985 * Note that it does set_restore_sigmask() in advance, so it must be always
2986 * paired with restore_saved_sigmask_unless() before return from syscall.
2988 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
2994 if (sigsetsize != sizeof(sigset_t))
2996 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
2999 set_restore_sigmask();
3000 current->saved_sigmask = current->blocked;
3001 set_current_blocked(&kmask);
3006 #ifdef CONFIG_COMPAT
3007 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3014 if (sigsetsize != sizeof(compat_sigset_t))
3016 if (get_compat_sigset(&kmask, umask))
3019 set_restore_sigmask();
3020 current->saved_sigmask = current->blocked;
3021 set_current_blocked(&kmask);
3028 * sys_rt_sigprocmask - change the list of currently blocked signals
3029 * @how: whether to add, remove, or set signals
3030 * @nset: stores pending signals
3031 * @oset: previous value of signal mask if non-null
3032 * @sigsetsize: size of sigset_t type
3034 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3035 sigset_t __user *, oset, size_t, sigsetsize)
3037 sigset_t old_set, new_set;
3040 /* XXX: Don't preclude handling different sized sigset_t's. */
3041 if (sigsetsize != sizeof(sigset_t))
3044 old_set = current->blocked;
3047 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3049 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3051 error = sigprocmask(how, &new_set, NULL);
3057 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3064 #ifdef CONFIG_COMPAT
3065 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3066 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3068 sigset_t old_set = current->blocked;
3070 /* XXX: Don't preclude handling different sized sigset_t's. */
3071 if (sigsetsize != sizeof(sigset_t))
3077 if (get_compat_sigset(&new_set, nset))
3079 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3081 error = sigprocmask(how, &new_set, NULL);
3085 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3089 static void do_sigpending(sigset_t *set)
3091 spin_lock_irq(¤t->sighand->siglock);
3092 sigorsets(set, ¤t->pending.signal,
3093 ¤t->signal->shared_pending.signal);
3094 spin_unlock_irq(¤t->sighand->siglock);
3096 /* Outside the lock because only this thread touches it. */
3097 sigandsets(set, ¤t->blocked, set);
3101 * sys_rt_sigpending - examine a pending signal that has been raised
3103 * @uset: stores pending signals
3104 * @sigsetsize: size of sigset_t type or larger
3106 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3110 if (sigsetsize > sizeof(*uset))
3113 do_sigpending(&set);
3115 if (copy_to_user(uset, &set, sigsetsize))
3121 #ifdef CONFIG_COMPAT
3122 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3123 compat_size_t, sigsetsize)
3127 if (sigsetsize > sizeof(*uset))
3130 do_sigpending(&set);
3132 return put_compat_sigset(uset, &set, sigsetsize);
3136 static const struct {
3137 unsigned char limit, layout;
3139 [SIGILL] = { NSIGILL, SIL_FAULT },
3140 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3141 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3142 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3143 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3145 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3147 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3148 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3149 [SIGSYS] = { NSIGSYS, SIL_SYS },
3152 static bool known_siginfo_layout(unsigned sig, int si_code)
3154 if (si_code == SI_KERNEL)
3156 else if ((si_code > SI_USER)) {
3157 if (sig_specific_sicodes(sig)) {
3158 if (si_code <= sig_sicodes[sig].limit)
3161 else if (si_code <= NSIGPOLL)
3164 else if (si_code >= SI_DETHREAD)
3166 else if (si_code == SI_ASYNCNL)
3171 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3173 enum siginfo_layout layout = SIL_KILL;
3174 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3175 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3176 (si_code <= sig_sicodes[sig].limit)) {
3177 layout = sig_sicodes[sig].layout;
3178 /* Handle the exceptions */
3179 if ((sig == SIGBUS) &&
3180 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3181 layout = SIL_FAULT_MCEERR;
3182 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3183 layout = SIL_FAULT_BNDERR;
3185 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3186 layout = SIL_FAULT_PKUERR;
3189 else if (si_code <= NSIGPOLL)
3192 if (si_code == SI_TIMER)
3194 else if (si_code == SI_SIGIO)
3196 else if (si_code < 0)
3202 static inline char __user *si_expansion(const siginfo_t __user *info)
3204 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3207 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3209 char __user *expansion = si_expansion(to);
3210 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3212 if (clear_user(expansion, SI_EXPANSION_SIZE))
3217 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3218 const siginfo_t __user *from)
3220 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3221 char __user *expansion = si_expansion(from);
3222 char buf[SI_EXPANSION_SIZE];
3225 * An unknown si_code might need more than
3226 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3227 * extra bytes are 0. This guarantees copy_siginfo_to_user
3228 * will return this data to userspace exactly.
3230 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3232 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3240 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3241 const siginfo_t __user *from)
3243 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3245 to->si_signo = signo;
3246 return post_copy_siginfo_from_user(to, from);
3249 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3251 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3253 return post_copy_siginfo_from_user(to, from);
3256 #ifdef CONFIG_COMPAT
3258 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3259 * @to: compat siginfo destination
3260 * @from: kernel siginfo source
3262 * Note: This function does not work properly for the SIGCHLD on x32, but
3263 * fortunately it doesn't have to. The only valid callers for this function are
3264 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3265 * The latter does not care because SIGCHLD will never cause a coredump.
3267 void copy_siginfo_to_external32(struct compat_siginfo *to,
3268 const struct kernel_siginfo *from)
3270 memset(to, 0, sizeof(*to));
3272 to->si_signo = from->si_signo;
3273 to->si_errno = from->si_errno;
3274 to->si_code = from->si_code;
3275 switch(siginfo_layout(from->si_signo, from->si_code)) {
3277 to->si_pid = from->si_pid;
3278 to->si_uid = from->si_uid;
3281 to->si_tid = from->si_tid;
3282 to->si_overrun = from->si_overrun;
3283 to->si_int = from->si_int;
3286 to->si_band = from->si_band;
3287 to->si_fd = from->si_fd;
3290 to->si_addr = ptr_to_compat(from->si_addr);
3291 #ifdef __ARCH_SI_TRAPNO
3292 to->si_trapno = from->si_trapno;
3295 case SIL_FAULT_MCEERR:
3296 to->si_addr = ptr_to_compat(from->si_addr);
3297 #ifdef __ARCH_SI_TRAPNO
3298 to->si_trapno = from->si_trapno;
3300 to->si_addr_lsb = from->si_addr_lsb;
3302 case SIL_FAULT_BNDERR:
3303 to->si_addr = ptr_to_compat(from->si_addr);
3304 #ifdef __ARCH_SI_TRAPNO
3305 to->si_trapno = from->si_trapno;
3307 to->si_lower = ptr_to_compat(from->si_lower);
3308 to->si_upper = ptr_to_compat(from->si_upper);
3310 case SIL_FAULT_PKUERR:
3311 to->si_addr = ptr_to_compat(from->si_addr);
3312 #ifdef __ARCH_SI_TRAPNO
3313 to->si_trapno = from->si_trapno;
3315 to->si_pkey = from->si_pkey;
3318 to->si_pid = from->si_pid;
3319 to->si_uid = from->si_uid;
3320 to->si_status = from->si_status;
3321 to->si_utime = from->si_utime;
3322 to->si_stime = from->si_stime;
3325 to->si_pid = from->si_pid;
3326 to->si_uid = from->si_uid;
3327 to->si_int = from->si_int;
3330 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3331 to->si_syscall = from->si_syscall;
3332 to->si_arch = from->si_arch;
3337 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3338 const struct kernel_siginfo *from)
3340 struct compat_siginfo new;
3342 copy_siginfo_to_external32(&new, from);
3343 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3348 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3349 const struct compat_siginfo *from)
3352 to->si_signo = from->si_signo;
3353 to->si_errno = from->si_errno;
3354 to->si_code = from->si_code;
3355 switch(siginfo_layout(from->si_signo, from->si_code)) {
3357 to->si_pid = from->si_pid;
3358 to->si_uid = from->si_uid;
3361 to->si_tid = from->si_tid;
3362 to->si_overrun = from->si_overrun;
3363 to->si_int = from->si_int;
3366 to->si_band = from->si_band;
3367 to->si_fd = from->si_fd;
3370 to->si_addr = compat_ptr(from->si_addr);
3371 #ifdef __ARCH_SI_TRAPNO
3372 to->si_trapno = from->si_trapno;
3375 case SIL_FAULT_MCEERR:
3376 to->si_addr = compat_ptr(from->si_addr);
3377 #ifdef __ARCH_SI_TRAPNO
3378 to->si_trapno = from->si_trapno;
3380 to->si_addr_lsb = from->si_addr_lsb;
3382 case SIL_FAULT_BNDERR:
3383 to->si_addr = compat_ptr(from->si_addr);
3384 #ifdef __ARCH_SI_TRAPNO
3385 to->si_trapno = from->si_trapno;
3387 to->si_lower = compat_ptr(from->si_lower);
3388 to->si_upper = compat_ptr(from->si_upper);
3390 case SIL_FAULT_PKUERR:
3391 to->si_addr = compat_ptr(from->si_addr);
3392 #ifdef __ARCH_SI_TRAPNO
3393 to->si_trapno = from->si_trapno;
3395 to->si_pkey = from->si_pkey;
3398 to->si_pid = from->si_pid;
3399 to->si_uid = from->si_uid;
3400 to->si_status = from->si_status;
3401 #ifdef CONFIG_X86_X32_ABI
3402 if (in_x32_syscall()) {
3403 to->si_utime = from->_sifields._sigchld_x32._utime;
3404 to->si_stime = from->_sifields._sigchld_x32._stime;
3408 to->si_utime = from->si_utime;
3409 to->si_stime = from->si_stime;
3413 to->si_pid = from->si_pid;
3414 to->si_uid = from->si_uid;
3415 to->si_int = from->si_int;
3418 to->si_call_addr = compat_ptr(from->si_call_addr);
3419 to->si_syscall = from->si_syscall;
3420 to->si_arch = from->si_arch;
3426 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3427 const struct compat_siginfo __user *ufrom)
3429 struct compat_siginfo from;
3431 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3434 from.si_signo = signo;
3435 return post_copy_siginfo_from_user32(to, &from);
3438 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3439 const struct compat_siginfo __user *ufrom)
3441 struct compat_siginfo from;
3443 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3446 return post_copy_siginfo_from_user32(to, &from);
3448 #endif /* CONFIG_COMPAT */
3451 * do_sigtimedwait - wait for queued signals specified in @which
3452 * @which: queued signals to wait for
3453 * @info: if non-null, the signal's siginfo is returned here
3454 * @ts: upper bound on process time suspension
3456 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3457 const struct timespec64 *ts)
3459 ktime_t *to = NULL, timeout = KTIME_MAX;
3460 struct task_struct *tsk = current;
3461 sigset_t mask = *which;
3465 if (!timespec64_valid(ts))
3467 timeout = timespec64_to_ktime(*ts);
3472 * Invert the set of allowed signals to get those we want to block.
3474 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3477 spin_lock_irq(&tsk->sighand->siglock);
3478 sig = dequeue_signal(tsk, &mask, info);
3479 if (!sig && timeout) {
3481 * None ready, temporarily unblock those we're interested
3482 * while we are sleeping in so that we'll be awakened when
3483 * they arrive. Unblocking is always fine, we can avoid
3484 * set_current_blocked().
3486 tsk->real_blocked = tsk->blocked;
3487 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3488 recalc_sigpending();
3489 spin_unlock_irq(&tsk->sighand->siglock);
3491 __set_current_state(TASK_INTERRUPTIBLE);
3492 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3494 spin_lock_irq(&tsk->sighand->siglock);
3495 __set_task_blocked(tsk, &tsk->real_blocked);
3496 sigemptyset(&tsk->real_blocked);
3497 sig = dequeue_signal(tsk, &mask, info);
3499 spin_unlock_irq(&tsk->sighand->siglock);
3503 return ret ? -EINTR : -EAGAIN;
3507 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3509 * @uthese: queued signals to wait for
3510 * @uinfo: if non-null, the signal's siginfo is returned here
3511 * @uts: upper bound on process time suspension
3512 * @sigsetsize: size of sigset_t type
3514 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3515 siginfo_t __user *, uinfo,
3516 const struct __kernel_timespec __user *, uts,
3520 struct timespec64 ts;
3521 kernel_siginfo_t info;
3524 /* XXX: Don't preclude handling different sized sigset_t's. */
3525 if (sigsetsize != sizeof(sigset_t))
3528 if (copy_from_user(&these, uthese, sizeof(these)))
3532 if (get_timespec64(&ts, uts))
3536 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3538 if (ret > 0 && uinfo) {
3539 if (copy_siginfo_to_user(uinfo, &info))
3546 #ifdef CONFIG_COMPAT_32BIT_TIME
3547 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3548 siginfo_t __user *, uinfo,
3549 const struct old_timespec32 __user *, uts,
3553 struct timespec64 ts;
3554 kernel_siginfo_t info;
3557 if (sigsetsize != sizeof(sigset_t))
3560 if (copy_from_user(&these, uthese, sizeof(these)))
3564 if (get_old_timespec32(&ts, uts))
3568 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3570 if (ret > 0 && uinfo) {
3571 if (copy_siginfo_to_user(uinfo, &info))
3579 #ifdef CONFIG_COMPAT
3580 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3581 struct compat_siginfo __user *, uinfo,
3582 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3585 struct timespec64 t;
3586 kernel_siginfo_t info;
3589 if (sigsetsize != sizeof(sigset_t))
3592 if (get_compat_sigset(&s, uthese))
3596 if (get_timespec64(&t, uts))
3600 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3602 if (ret > 0 && uinfo) {
3603 if (copy_siginfo_to_user32(uinfo, &info))
3610 #ifdef CONFIG_COMPAT_32BIT_TIME
3611 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3612 struct compat_siginfo __user *, uinfo,
3613 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3616 struct timespec64 t;
3617 kernel_siginfo_t info;
3620 if (sigsetsize != sizeof(sigset_t))
3623 if (get_compat_sigset(&s, uthese))
3627 if (get_old_timespec32(&t, uts))
3631 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3633 if (ret > 0 && uinfo) {
3634 if (copy_siginfo_to_user32(uinfo, &info))
3643 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3645 clear_siginfo(info);
3646 info->si_signo = sig;
3648 info->si_code = SI_USER;
3649 info->si_pid = task_tgid_vnr(current);
3650 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3654 * sys_kill - send a signal to a process
3655 * @pid: the PID of the process
3656 * @sig: signal to be sent
3658 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3660 struct kernel_siginfo info;
3662 prepare_kill_siginfo(sig, &info);
3664 return kill_something_info(sig, &info, pid);
3668 * Verify that the signaler and signalee either are in the same pid namespace
3669 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3672 static bool access_pidfd_pidns(struct pid *pid)
3674 struct pid_namespace *active = task_active_pid_ns(current);
3675 struct pid_namespace *p = ns_of_pid(pid);
3688 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, siginfo_t *info)
3690 #ifdef CONFIG_COMPAT
3692 * Avoid hooking up compat syscalls and instead handle necessary
3693 * conversions here. Note, this is a stop-gap measure and should not be
3694 * considered a generic solution.
3696 if (in_compat_syscall())
3697 return copy_siginfo_from_user32(
3698 kinfo, (struct compat_siginfo __user *)info);
3700 return copy_siginfo_from_user(kinfo, info);
3703 static struct pid *pidfd_to_pid(const struct file *file)
3707 pid = pidfd_pid(file);
3711 return tgid_pidfd_to_pid(file);
3715 * sys_pidfd_send_signal - Signal a process through a pidfd
3716 * @pidfd: file descriptor of the process
3717 * @sig: signal to send
3718 * @info: signal info
3719 * @flags: future flags
3721 * The syscall currently only signals via PIDTYPE_PID which covers
3722 * kill(<positive-pid>, <signal>. It does not signal threads or process
3724 * In order to extend the syscall to threads and process groups the @flags
3725 * argument should be used. In essence, the @flags argument will determine
3726 * what is signaled and not the file descriptor itself. Put in other words,
3727 * grouping is a property of the flags argument not a property of the file
3730 * Return: 0 on success, negative errno on failure
3732 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3733 siginfo_t __user *, info, unsigned int, flags)
3738 kernel_siginfo_t kinfo;
3740 /* Enforce flags be set to 0 until we add an extension. */
3748 /* Is this a pidfd? */
3749 pid = pidfd_to_pid(f.file);
3756 if (!access_pidfd_pidns(pid))
3760 ret = copy_siginfo_from_user_any(&kinfo, info);
3765 if (unlikely(sig != kinfo.si_signo))
3768 /* Only allow sending arbitrary signals to yourself. */
3770 if ((task_pid(current) != pid) &&
3771 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3774 prepare_kill_siginfo(sig, &kinfo);
3777 ret = kill_pid_info(sig, &kinfo, pid);
3785 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3787 struct task_struct *p;
3791 p = find_task_by_vpid(pid);
3792 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3793 error = check_kill_permission(sig, info, p);
3795 * The null signal is a permissions and process existence
3796 * probe. No signal is actually delivered.
3798 if (!error && sig) {
3799 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3801 * If lock_task_sighand() failed we pretend the task
3802 * dies after receiving the signal. The window is tiny,
3803 * and the signal is private anyway.
3805 if (unlikely(error == -ESRCH))
3814 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3816 struct kernel_siginfo info;
3818 clear_siginfo(&info);
3819 info.si_signo = sig;
3821 info.si_code = SI_TKILL;
3822 info.si_pid = task_tgid_vnr(current);
3823 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3825 return do_send_specific(tgid, pid, sig, &info);
3829 * sys_tgkill - send signal to one specific thread
3830 * @tgid: the thread group ID of the thread
3831 * @pid: the PID of the thread
3832 * @sig: signal to be sent
3834 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3835 * exists but it's not belonging to the target process anymore. This
3836 * method solves the problem of threads exiting and PIDs getting reused.
3838 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3840 /* This is only valid for single tasks */
3841 if (pid <= 0 || tgid <= 0)
3844 return do_tkill(tgid, pid, sig);
3848 * sys_tkill - send signal to one specific task
3849 * @pid: the PID of the task
3850 * @sig: signal to be sent
3852 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3854 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3856 /* This is only valid for single tasks */
3860 return do_tkill(0, pid, sig);
3863 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3865 /* Not even root can pretend to send signals from the kernel.
3866 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3868 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3869 (task_pid_vnr(current) != pid))
3872 /* POSIX.1b doesn't mention process groups. */
3873 return kill_proc_info(sig, info, pid);
3877 * sys_rt_sigqueueinfo - send signal information to a signal
3878 * @pid: the PID of the thread
3879 * @sig: signal to be sent
3880 * @uinfo: signal info to be sent
3882 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3883 siginfo_t __user *, uinfo)
3885 kernel_siginfo_t info;
3886 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3889 return do_rt_sigqueueinfo(pid, sig, &info);
3892 #ifdef CONFIG_COMPAT
3893 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3896 struct compat_siginfo __user *, uinfo)
3898 kernel_siginfo_t info;
3899 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3902 return do_rt_sigqueueinfo(pid, sig, &info);
3906 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
3908 /* This is only valid for single tasks */
3909 if (pid <= 0 || tgid <= 0)
3912 /* Not even root can pretend to send signals from the kernel.
3913 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3915 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3916 (task_pid_vnr(current) != pid))
3919 return do_send_specific(tgid, pid, sig, info);
3922 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3923 siginfo_t __user *, uinfo)
3925 kernel_siginfo_t info;
3926 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3929 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3932 #ifdef CONFIG_COMPAT
3933 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3937 struct compat_siginfo __user *, uinfo)
3939 kernel_siginfo_t info;
3940 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3943 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3948 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3950 void kernel_sigaction(int sig, __sighandler_t action)
3952 spin_lock_irq(¤t->sighand->siglock);
3953 current->sighand->action[sig - 1].sa.sa_handler = action;
3954 if (action == SIG_IGN) {
3958 sigaddset(&mask, sig);
3960 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3961 flush_sigqueue_mask(&mask, ¤t->pending);
3962 recalc_sigpending();
3964 spin_unlock_irq(¤t->sighand->siglock);
3966 EXPORT_SYMBOL(kernel_sigaction);
3968 void __weak sigaction_compat_abi(struct k_sigaction *act,
3969 struct k_sigaction *oact)
3973 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3975 struct task_struct *p = current, *t;
3976 struct k_sigaction *k;
3979 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3982 k = &p->sighand->action[sig-1];
3984 spin_lock_irq(&p->sighand->siglock);
3988 sigaction_compat_abi(act, oact);
3991 sigdelsetmask(&act->sa.sa_mask,
3992 sigmask(SIGKILL) | sigmask(SIGSTOP));
3996 * "Setting a signal action to SIG_IGN for a signal that is
3997 * pending shall cause the pending signal to be discarded,
3998 * whether or not it is blocked."
4000 * "Setting a signal action to SIG_DFL for a signal that is
4001 * pending and whose default action is to ignore the signal
4002 * (for example, SIGCHLD), shall cause the pending signal to
4003 * be discarded, whether or not it is blocked"
4005 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
4007 sigaddset(&mask, sig);
4008 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
4009 for_each_thread(p, t)
4010 flush_sigqueue_mask(&mask, &t->pending);
4014 spin_unlock_irq(&p->sighand->siglock);
4019 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4022 struct task_struct *t = current;
4025 memset(oss, 0, sizeof(stack_t));
4026 oss->ss_sp = (void __user *) t->sas_ss_sp;
4027 oss->ss_size = t->sas_ss_size;
4028 oss->ss_flags = sas_ss_flags(sp) |
4029 (current->sas_ss_flags & SS_FLAG_BITS);
4033 void __user *ss_sp = ss->ss_sp;
4034 size_t ss_size = ss->ss_size;
4035 unsigned ss_flags = ss->ss_flags;
4038 if (unlikely(on_sig_stack(sp)))
4041 ss_mode = ss_flags & ~SS_FLAG_BITS;
4042 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4046 if (ss_mode == SS_DISABLE) {
4050 if (unlikely(ss_size < min_ss_size))
4054 t->sas_ss_sp = (unsigned long) ss_sp;
4055 t->sas_ss_size = ss_size;
4056 t->sas_ss_flags = ss_flags;
4061 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4065 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4067 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4068 current_user_stack_pointer(),
4070 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4075 int restore_altstack(const stack_t __user *uss)
4078 if (copy_from_user(&new, uss, sizeof(stack_t)))
4080 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4082 /* squash all but EFAULT for now */
4086 int __save_altstack(stack_t __user *uss, unsigned long sp)
4088 struct task_struct *t = current;
4089 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4090 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4091 __put_user(t->sas_ss_size, &uss->ss_size);
4094 if (t->sas_ss_flags & SS_AUTODISARM)
4099 #ifdef CONFIG_COMPAT
4100 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4101 compat_stack_t __user *uoss_ptr)
4107 compat_stack_t uss32;
4108 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4110 uss.ss_sp = compat_ptr(uss32.ss_sp);
4111 uss.ss_flags = uss32.ss_flags;
4112 uss.ss_size = uss32.ss_size;
4114 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4115 compat_user_stack_pointer(),
4116 COMPAT_MINSIGSTKSZ);
4117 if (ret >= 0 && uoss_ptr) {
4119 memset(&old, 0, sizeof(old));
4120 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4121 old.ss_flags = uoss.ss_flags;
4122 old.ss_size = uoss.ss_size;
4123 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4129 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4130 const compat_stack_t __user *, uss_ptr,
4131 compat_stack_t __user *, uoss_ptr)
4133 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4136 int compat_restore_altstack(const compat_stack_t __user *uss)
4138 int err = do_compat_sigaltstack(uss, NULL);
4139 /* squash all but -EFAULT for now */
4140 return err == -EFAULT ? err : 0;
4143 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4146 struct task_struct *t = current;
4147 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4149 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4150 __put_user(t->sas_ss_size, &uss->ss_size);
4153 if (t->sas_ss_flags & SS_AUTODISARM)
4159 #ifdef __ARCH_WANT_SYS_SIGPENDING
4162 * sys_sigpending - examine pending signals
4163 * @uset: where mask of pending signal is returned
4165 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4169 if (sizeof(old_sigset_t) > sizeof(*uset))
4172 do_sigpending(&set);
4174 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4180 #ifdef CONFIG_COMPAT
4181 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4185 do_sigpending(&set);
4187 return put_user(set.sig[0], set32);
4193 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4195 * sys_sigprocmask - examine and change blocked signals
4196 * @how: whether to add, remove, or set signals
4197 * @nset: signals to add or remove (if non-null)
4198 * @oset: previous value of signal mask if non-null
4200 * Some platforms have their own version with special arguments;
4201 * others support only sys_rt_sigprocmask.
4204 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4205 old_sigset_t __user *, oset)
4207 old_sigset_t old_set, new_set;
4208 sigset_t new_blocked;
4210 old_set = current->blocked.sig[0];
4213 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4216 new_blocked = current->blocked;
4220 sigaddsetmask(&new_blocked, new_set);
4223 sigdelsetmask(&new_blocked, new_set);
4226 new_blocked.sig[0] = new_set;
4232 set_current_blocked(&new_blocked);
4236 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4242 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4244 #ifndef CONFIG_ODD_RT_SIGACTION
4246 * sys_rt_sigaction - alter an action taken by a process
4247 * @sig: signal to be sent
4248 * @act: new sigaction
4249 * @oact: used to save the previous sigaction
4250 * @sigsetsize: size of sigset_t type
4252 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4253 const struct sigaction __user *, act,
4254 struct sigaction __user *, oact,
4257 struct k_sigaction new_sa, old_sa;
4260 /* XXX: Don't preclude handling different sized sigset_t's. */
4261 if (sigsetsize != sizeof(sigset_t))
4264 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4267 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4271 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4276 #ifdef CONFIG_COMPAT
4277 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4278 const struct compat_sigaction __user *, act,
4279 struct compat_sigaction __user *, oact,
4280 compat_size_t, sigsetsize)
4282 struct k_sigaction new_ka, old_ka;
4283 #ifdef __ARCH_HAS_SA_RESTORER
4284 compat_uptr_t restorer;
4288 /* XXX: Don't preclude handling different sized sigset_t's. */
4289 if (sigsetsize != sizeof(compat_sigset_t))
4293 compat_uptr_t handler;
4294 ret = get_user(handler, &act->sa_handler);
4295 new_ka.sa.sa_handler = compat_ptr(handler);
4296 #ifdef __ARCH_HAS_SA_RESTORER
4297 ret |= get_user(restorer, &act->sa_restorer);
4298 new_ka.sa.sa_restorer = compat_ptr(restorer);
4300 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4301 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4306 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4308 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4310 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4311 sizeof(oact->sa_mask));
4312 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4313 #ifdef __ARCH_HAS_SA_RESTORER
4314 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4315 &oact->sa_restorer);
4321 #endif /* !CONFIG_ODD_RT_SIGACTION */
4323 #ifdef CONFIG_OLD_SIGACTION
4324 SYSCALL_DEFINE3(sigaction, int, sig,
4325 const struct old_sigaction __user *, act,
4326 struct old_sigaction __user *, oact)
4328 struct k_sigaction new_ka, old_ka;
4333 if (!access_ok(act, sizeof(*act)) ||
4334 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4335 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4336 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4337 __get_user(mask, &act->sa_mask))
4339 #ifdef __ARCH_HAS_KA_RESTORER
4340 new_ka.ka_restorer = NULL;
4342 siginitset(&new_ka.sa.sa_mask, mask);
4345 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4348 if (!access_ok(oact, sizeof(*oact)) ||
4349 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4350 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4351 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4352 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4359 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4360 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4361 const struct compat_old_sigaction __user *, act,
4362 struct compat_old_sigaction __user *, oact)
4364 struct k_sigaction new_ka, old_ka;
4366 compat_old_sigset_t mask;
4367 compat_uptr_t handler, restorer;
4370 if (!access_ok(act, sizeof(*act)) ||
4371 __get_user(handler, &act->sa_handler) ||
4372 __get_user(restorer, &act->sa_restorer) ||
4373 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4374 __get_user(mask, &act->sa_mask))
4377 #ifdef __ARCH_HAS_KA_RESTORER
4378 new_ka.ka_restorer = NULL;
4380 new_ka.sa.sa_handler = compat_ptr(handler);
4381 new_ka.sa.sa_restorer = compat_ptr(restorer);
4382 siginitset(&new_ka.sa.sa_mask, mask);
4385 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4388 if (!access_ok(oact, sizeof(*oact)) ||
4389 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4390 &oact->sa_handler) ||
4391 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4392 &oact->sa_restorer) ||
4393 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4394 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4401 #ifdef CONFIG_SGETMASK_SYSCALL
4404 * For backwards compatibility. Functionality superseded by sigprocmask.
4406 SYSCALL_DEFINE0(sgetmask)
4409 return current->blocked.sig[0];
4412 SYSCALL_DEFINE1(ssetmask, int, newmask)
4414 int old = current->blocked.sig[0];
4417 siginitset(&newset, newmask);
4418 set_current_blocked(&newset);
4422 #endif /* CONFIG_SGETMASK_SYSCALL */
4424 #ifdef __ARCH_WANT_SYS_SIGNAL
4426 * For backwards compatibility. Functionality superseded by sigaction.
4428 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4430 struct k_sigaction new_sa, old_sa;
4433 new_sa.sa.sa_handler = handler;
4434 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4435 sigemptyset(&new_sa.sa.sa_mask);
4437 ret = do_sigaction(sig, &new_sa, &old_sa);
4439 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4441 #endif /* __ARCH_WANT_SYS_SIGNAL */
4443 #ifdef __ARCH_WANT_SYS_PAUSE
4445 SYSCALL_DEFINE0(pause)
4447 while (!signal_pending(current)) {
4448 __set_current_state(TASK_INTERRUPTIBLE);
4451 return -ERESTARTNOHAND;
4456 static int sigsuspend(sigset_t *set)
4458 current->saved_sigmask = current->blocked;
4459 set_current_blocked(set);
4461 while (!signal_pending(current)) {
4462 __set_current_state(TASK_INTERRUPTIBLE);
4465 set_restore_sigmask();
4466 return -ERESTARTNOHAND;
4470 * sys_rt_sigsuspend - replace the signal mask for a value with the
4471 * @unewset value until a signal is received
4472 * @unewset: new signal mask value
4473 * @sigsetsize: size of sigset_t type
4475 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4479 /* XXX: Don't preclude handling different sized sigset_t's. */
4480 if (sigsetsize != sizeof(sigset_t))
4483 if (copy_from_user(&newset, unewset, sizeof(newset)))
4485 return sigsuspend(&newset);
4488 #ifdef CONFIG_COMPAT
4489 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4493 /* XXX: Don't preclude handling different sized sigset_t's. */
4494 if (sigsetsize != sizeof(sigset_t))
4497 if (get_compat_sigset(&newset, unewset))
4499 return sigsuspend(&newset);
4503 #ifdef CONFIG_OLD_SIGSUSPEND
4504 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4507 siginitset(&blocked, mask);
4508 return sigsuspend(&blocked);
4511 #ifdef CONFIG_OLD_SIGSUSPEND3
4512 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4515 siginitset(&blocked, mask);
4516 return sigsuspend(&blocked);
4520 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4525 static inline void siginfo_buildtime_checks(void)
4527 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4529 /* Verify the offsets in the two siginfos match */
4530 #define CHECK_OFFSET(field) \
4531 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4534 CHECK_OFFSET(si_pid);
4535 CHECK_OFFSET(si_uid);
4538 CHECK_OFFSET(si_tid);
4539 CHECK_OFFSET(si_overrun);
4540 CHECK_OFFSET(si_value);
4543 CHECK_OFFSET(si_pid);
4544 CHECK_OFFSET(si_uid);
4545 CHECK_OFFSET(si_value);
4548 CHECK_OFFSET(si_pid);
4549 CHECK_OFFSET(si_uid);
4550 CHECK_OFFSET(si_status);
4551 CHECK_OFFSET(si_utime);
4552 CHECK_OFFSET(si_stime);
4555 CHECK_OFFSET(si_addr);
4556 CHECK_OFFSET(si_addr_lsb);
4557 CHECK_OFFSET(si_lower);
4558 CHECK_OFFSET(si_upper);
4559 CHECK_OFFSET(si_pkey);
4562 CHECK_OFFSET(si_band);
4563 CHECK_OFFSET(si_fd);
4566 CHECK_OFFSET(si_call_addr);
4567 CHECK_OFFSET(si_syscall);
4568 CHECK_OFFSET(si_arch);
4572 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4573 offsetof(struct siginfo, si_addr));
4574 if (sizeof(int) == sizeof(void __user *)) {
4575 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4576 sizeof(void __user *));
4578 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4579 sizeof_field(struct siginfo, si_uid)) !=
4580 sizeof(void __user *));
4581 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4582 offsetof(struct siginfo, si_uid));
4584 #ifdef CONFIG_COMPAT
4585 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4586 offsetof(struct compat_siginfo, si_addr));
4587 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4588 sizeof(compat_uptr_t));
4589 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4590 sizeof_field(struct siginfo, si_pid));
4594 void __init signals_init(void)
4596 siginfo_buildtime_checks();
4598 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
4601 #ifdef CONFIG_KGDB_KDB
4602 #include <linux/kdb.h>
4604 * kdb_send_sig - Allows kdb to send signals without exposing
4605 * signal internals. This function checks if the required locks are
4606 * available before calling the main signal code, to avoid kdb
4609 void kdb_send_sig(struct task_struct *t, int sig)
4611 static struct task_struct *kdb_prev_t;
4613 if (!spin_trylock(&t->sighand->siglock)) {
4614 kdb_printf("Can't do kill command now.\n"
4615 "The sigmask lock is held somewhere else in "
4616 "kernel, try again later\n");
4619 new_t = kdb_prev_t != t;
4621 if (t->state != TASK_RUNNING && new_t) {
4622 spin_unlock(&t->sighand->siglock);
4623 kdb_printf("Process is not RUNNING, sending a signal from "
4624 "kdb risks deadlock\n"
4625 "on the run queue locks. "
4626 "The signal has _not_ been sent.\n"
4627 "Reissue the kill command if you want to risk "
4631 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4632 spin_unlock(&t->sighand->siglock);
4634 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4637 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4639 #endif /* CONFIG_KGDB_KDB */