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/task_work.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/cgroup.h>
47 #include <linux/audit.h>
49 #define CREATE_TRACE_POINTS
50 #include <trace/events/signal.h>
52 #include <asm/param.h>
53 #include <linux/uaccess.h>
54 #include <asm/unistd.h>
55 #include <asm/siginfo.h>
56 #include <asm/cacheflush.h>
57 #include <asm/syscall.h> /* for syscall_get_* */
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 clear_thread_flag(TIF_SIGPENDING);
188 EXPORT_SYMBOL(recalc_sigpending);
190 void calculate_sigpending(void)
192 /* Have any signals or users of TIF_SIGPENDING been delayed
195 spin_lock_irq(¤t->sighand->siglock);
196 set_tsk_thread_flag(current, TIF_SIGPENDING);
198 spin_unlock_irq(¤t->sighand->siglock);
201 /* Given the mask, find the first available signal that should be serviced. */
203 #define SYNCHRONOUS_MASK \
204 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
205 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
207 int next_signal(struct sigpending *pending, sigset_t *mask)
209 unsigned long i, *s, *m, x;
212 s = pending->signal.sig;
216 * Handle the first word specially: it contains the
217 * synchronous signals that need to be dequeued first.
221 if (x & SYNCHRONOUS_MASK)
222 x &= SYNCHRONOUS_MASK;
227 switch (_NSIG_WORDS) {
229 for (i = 1; i < _NSIG_WORDS; ++i) {
233 sig = ffz(~x) + i*_NSIG_BPW + 1;
242 sig = ffz(~x) + _NSIG_BPW + 1;
253 static inline void print_dropped_signal(int sig)
255 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
257 if (!print_fatal_signals)
260 if (!__ratelimit(&ratelimit_state))
263 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
264 current->comm, current->pid, sig);
268 * task_set_jobctl_pending - set jobctl pending bits
270 * @mask: pending bits to set
272 * Clear @mask from @task->jobctl. @mask must be subset of
273 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
274 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
275 * cleared. If @task is already being killed or exiting, this function
279 * Must be called with @task->sighand->siglock held.
282 * %true if @mask is set, %false if made noop because @task was dying.
284 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
286 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
287 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
288 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
290 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
293 if (mask & JOBCTL_STOP_SIGMASK)
294 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
296 task->jobctl |= mask;
301 * task_clear_jobctl_trapping - clear jobctl trapping bit
304 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
305 * Clear it and wake up the ptracer. Note that we don't need any further
306 * locking. @task->siglock guarantees that @task->parent points to the
310 * Must be called with @task->sighand->siglock held.
312 void task_clear_jobctl_trapping(struct task_struct *task)
314 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
315 task->jobctl &= ~JOBCTL_TRAPPING;
316 smp_mb(); /* advised by wake_up_bit() */
317 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
322 * task_clear_jobctl_pending - clear jobctl pending bits
324 * @mask: pending bits to clear
326 * Clear @mask from @task->jobctl. @mask must be subset of
327 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
328 * STOP bits are cleared together.
330 * If clearing of @mask leaves no stop or trap pending, this function calls
331 * task_clear_jobctl_trapping().
334 * Must be called with @task->sighand->siglock held.
336 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
338 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
340 if (mask & JOBCTL_STOP_PENDING)
341 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
343 task->jobctl &= ~mask;
345 if (!(task->jobctl & JOBCTL_PENDING_MASK))
346 task_clear_jobctl_trapping(task);
350 * task_participate_group_stop - participate in a group stop
351 * @task: task participating in a group stop
353 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
354 * Group stop states are cleared and the group stop count is consumed if
355 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
356 * stop, the appropriate `SIGNAL_*` flags are set.
359 * Must be called with @task->sighand->siglock held.
362 * %true if group stop completion should be notified to the parent, %false
365 static bool task_participate_group_stop(struct task_struct *task)
367 struct signal_struct *sig = task->signal;
368 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
370 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
372 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
377 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
378 sig->group_stop_count--;
381 * Tell the caller to notify completion iff we are entering into a
382 * fresh group stop. Read comment in do_signal_stop() for details.
384 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
385 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
391 void task_join_group_stop(struct task_struct *task)
393 unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
394 struct signal_struct *sig = current->signal;
396 if (sig->group_stop_count) {
397 sig->group_stop_count++;
398 mask |= JOBCTL_STOP_CONSUME;
399 } else if (!(sig->flags & SIGNAL_STOP_STOPPED))
402 /* Have the new thread join an on-going signal group stop */
403 task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
407 * allocate a new signal queue record
408 * - this may be called without locks if and only if t == current, otherwise an
409 * appropriate lock must be held to stop the target task from exiting
411 static struct sigqueue *
412 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
413 int override_rlimit, const unsigned int sigqueue_flags)
415 struct sigqueue *q = NULL;
416 struct ucounts *ucounts = NULL;
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 ucounts = task_ucounts(t);
429 sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
434 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
435 q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
437 print_dropped_signal(sig);
440 if (unlikely(q == NULL)) {
441 dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
443 INIT_LIST_HEAD(&q->list);
444 q->flags = sigqueue_flags;
445 q->ucounts = ucounts;
450 static void __sigqueue_free(struct sigqueue *q)
452 if (q->flags & SIGQUEUE_PREALLOC)
455 dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_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,
630 kernel_siginfo_t *info, enum pid_type *type)
632 bool resched_timer = false;
635 /* We only dequeue private signals from ourselves, we don't let
636 * signalfd steal them
639 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
641 *type = PIDTYPE_TGID;
642 signr = __dequeue_signal(&tsk->signal->shared_pending,
643 mask, info, &resched_timer);
644 #ifdef CONFIG_POSIX_TIMERS
648 * itimers are process shared and we restart periodic
649 * itimers in the signal delivery path to prevent DoS
650 * attacks in the high resolution timer case. This is
651 * compliant with the old way of self-restarting
652 * itimers, as the SIGALRM is a legacy signal and only
653 * queued once. Changing the restart behaviour to
654 * restart the timer in the signal dequeue path is
655 * reducing the timer noise on heavy loaded !highres
658 if (unlikely(signr == SIGALRM)) {
659 struct hrtimer *tmr = &tsk->signal->real_timer;
661 if (!hrtimer_is_queued(tmr) &&
662 tsk->signal->it_real_incr != 0) {
663 hrtimer_forward(tmr, tmr->base->get_time(),
664 tsk->signal->it_real_incr);
665 hrtimer_restart(tmr);
675 if (unlikely(sig_kernel_stop(signr))) {
677 * Set a marker that we have dequeued a stop signal. Our
678 * caller might release the siglock and then the pending
679 * stop signal it is about to process is no longer in the
680 * pending bitmasks, but must still be cleared by a SIGCONT
681 * (and overruled by a SIGKILL). So those cases clear this
682 * shared flag after we've set it. Note that this flag may
683 * remain set after the signal we return is ignored or
684 * handled. That doesn't matter because its only purpose
685 * is to alert stop-signal processing code when another
686 * processor has come along and cleared the flag.
688 current->jobctl |= JOBCTL_STOP_DEQUEUED;
690 #ifdef CONFIG_POSIX_TIMERS
693 * Release the siglock to ensure proper locking order
694 * of timer locks outside of siglocks. Note, we leave
695 * irqs disabled here, since the posix-timers code is
696 * about to disable them again anyway.
698 spin_unlock(&tsk->sighand->siglock);
699 posixtimer_rearm(info);
700 spin_lock(&tsk->sighand->siglock);
702 /* Don't expose the si_sys_private value to userspace */
703 info->si_sys_private = 0;
708 EXPORT_SYMBOL_GPL(dequeue_signal);
710 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
712 struct task_struct *tsk = current;
713 struct sigpending *pending = &tsk->pending;
714 struct sigqueue *q, *sync = NULL;
717 * Might a synchronous signal be in the queue?
719 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
723 * Return the first synchronous signal in the queue.
725 list_for_each_entry(q, &pending->list, list) {
726 /* Synchronous signals have a positive si_code */
727 if ((q->info.si_code > SI_USER) &&
728 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
736 * Check if there is another siginfo for the same signal.
738 list_for_each_entry_continue(q, &pending->list, list) {
739 if (q->info.si_signo == sync->info.si_signo)
743 sigdelset(&pending->signal, sync->info.si_signo);
746 list_del_init(&sync->list);
747 copy_siginfo(info, &sync->info);
748 __sigqueue_free(sync);
749 return info->si_signo;
753 * Tell a process that it has a new active signal..
755 * NOTE! we rely on the previous spin_lock to
756 * lock interrupts for us! We can only be called with
757 * "siglock" held, and the local interrupt must
758 * have been disabled when that got acquired!
760 * No need to set need_resched since signal event passing
761 * goes through ->blocked
763 void signal_wake_up_state(struct task_struct *t, unsigned int state)
765 lockdep_assert_held(&t->sighand->siglock);
767 set_tsk_thread_flag(t, TIF_SIGPENDING);
770 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
771 * case. We don't check t->state here because there is a race with it
772 * executing another processor and just now entering stopped state.
773 * By using wake_up_state, we ensure the process will wake up and
774 * handle its death signal.
776 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
781 * Remove signals in mask from the pending set and queue.
782 * Returns 1 if any signals were found.
784 * All callers must be holding the siglock.
786 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
788 struct sigqueue *q, *n;
791 sigandsets(&m, mask, &s->signal);
792 if (sigisemptyset(&m))
795 sigandnsets(&s->signal, &s->signal, mask);
796 list_for_each_entry_safe(q, n, &s->list, list) {
797 if (sigismember(mask, q->info.si_signo)) {
798 list_del_init(&q->list);
804 static inline int is_si_special(const struct kernel_siginfo *info)
806 return info <= SEND_SIG_PRIV;
809 static inline bool si_fromuser(const struct kernel_siginfo *info)
811 return info == SEND_SIG_NOINFO ||
812 (!is_si_special(info) && SI_FROMUSER(info));
816 * called with RCU read lock from check_kill_permission()
818 static bool kill_ok_by_cred(struct task_struct *t)
820 const struct cred *cred = current_cred();
821 const struct cred *tcred = __task_cred(t);
823 return uid_eq(cred->euid, tcred->suid) ||
824 uid_eq(cred->euid, tcred->uid) ||
825 uid_eq(cred->uid, tcred->suid) ||
826 uid_eq(cred->uid, tcred->uid) ||
827 ns_capable(tcred->user_ns, CAP_KILL);
831 * Bad permissions for sending the signal
832 * - the caller must hold the RCU read lock
834 static int check_kill_permission(int sig, struct kernel_siginfo *info,
835 struct task_struct *t)
840 if (!valid_signal(sig))
843 if (!si_fromuser(info))
846 error = audit_signal_info(sig, t); /* Let audit system see the signal */
850 if (!same_thread_group(current, t) &&
851 !kill_ok_by_cred(t)) {
854 sid = task_session(t);
856 * We don't return the error if sid == NULL. The
857 * task was unhashed, the caller must notice this.
859 if (!sid || sid == task_session(current))
867 return security_task_kill(t, info, sig, NULL);
871 * ptrace_trap_notify - schedule trap to notify ptracer
872 * @t: tracee wanting to notify tracer
874 * This function schedules sticky ptrace trap which is cleared on the next
875 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
878 * If @t is running, STOP trap will be taken. If trapped for STOP and
879 * ptracer is listening for events, tracee is woken up so that it can
880 * re-trap for the new event. If trapped otherwise, STOP trap will be
881 * eventually taken without returning to userland after the existing traps
882 * are finished by PTRACE_CONT.
885 * Must be called with @task->sighand->siglock held.
887 static void ptrace_trap_notify(struct task_struct *t)
889 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
890 lockdep_assert_held(&t->sighand->siglock);
892 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
893 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
897 * Handle magic process-wide effects of stop/continue signals. Unlike
898 * the signal actions, these happen immediately at signal-generation
899 * time regardless of blocking, ignoring, or handling. This does the
900 * actual continuing for SIGCONT, but not the actual stopping for stop
901 * signals. The process stop is done as a signal action for SIG_DFL.
903 * Returns true if the signal should be actually delivered, otherwise
904 * it should be dropped.
906 static bool prepare_signal(int sig, struct task_struct *p, bool force)
908 struct signal_struct *signal = p->signal;
909 struct task_struct *t;
912 if (signal->flags & SIGNAL_GROUP_EXIT) {
913 if (signal->core_state)
914 return sig == SIGKILL;
916 * The process is in the middle of dying, drop the signal.
919 } else if (sig_kernel_stop(sig)) {
921 * This is a stop signal. Remove SIGCONT from all queues.
923 siginitset(&flush, sigmask(SIGCONT));
924 flush_sigqueue_mask(&flush, &signal->shared_pending);
925 for_each_thread(p, t)
926 flush_sigqueue_mask(&flush, &t->pending);
927 } else if (sig == SIGCONT) {
930 * Remove all stop signals from all queues, wake all threads.
932 siginitset(&flush, SIG_KERNEL_STOP_MASK);
933 flush_sigqueue_mask(&flush, &signal->shared_pending);
934 for_each_thread(p, t) {
935 flush_sigqueue_mask(&flush, &t->pending);
936 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
937 if (likely(!(t->ptrace & PT_SEIZED))) {
938 t->jobctl &= ~JOBCTL_STOPPED;
939 wake_up_state(t, __TASK_STOPPED);
941 ptrace_trap_notify(t);
945 * Notify the parent with CLD_CONTINUED if we were stopped.
947 * If we were in the middle of a group stop, we pretend it
948 * was already finished, and then continued. Since SIGCHLD
949 * doesn't queue we report only CLD_STOPPED, as if the next
950 * CLD_CONTINUED was dropped.
953 if (signal->flags & SIGNAL_STOP_STOPPED)
954 why |= SIGNAL_CLD_CONTINUED;
955 else if (signal->group_stop_count)
956 why |= SIGNAL_CLD_STOPPED;
960 * The first thread which returns from do_signal_stop()
961 * will take ->siglock, notice SIGNAL_CLD_MASK, and
962 * notify its parent. See get_signal().
964 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
965 signal->group_stop_count = 0;
966 signal->group_exit_code = 0;
970 return !sig_ignored(p, sig, force);
974 * Test if P wants to take SIG. After we've checked all threads with this,
975 * it's equivalent to finding no threads not blocking SIG. Any threads not
976 * blocking SIG were ruled out because they are not running and already
977 * have pending signals. Such threads will dequeue from the shared queue
978 * as soon as they're available, so putting the signal on the shared queue
979 * will be equivalent to sending it to one such thread.
981 static inline bool wants_signal(int sig, struct task_struct *p)
983 if (sigismember(&p->blocked, sig))
986 if (p->flags & PF_EXITING)
992 if (task_is_stopped_or_traced(p))
995 return task_curr(p) || !task_sigpending(p);
998 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
1000 struct signal_struct *signal = p->signal;
1001 struct task_struct *t;
1004 * Now find a thread we can wake up to take the signal off the queue.
1006 * If the main thread wants the signal, it gets first crack.
1007 * Probably the least surprising to the average bear.
1009 if (wants_signal(sig, p))
1011 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1013 * There is just one thread and it does not need to be woken.
1014 * It will dequeue unblocked signals before it runs again.
1019 * Otherwise try to find a suitable thread.
1021 t = signal->curr_target;
1022 while (!wants_signal(sig, t)) {
1024 if (t == signal->curr_target)
1026 * No thread needs to be woken.
1027 * Any eligible threads will see
1028 * the signal in the queue soon.
1032 signal->curr_target = t;
1036 * Found a killable thread. If the signal will be fatal,
1037 * then start taking the whole group down immediately.
1039 if (sig_fatal(p, sig) &&
1040 (signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) &&
1041 !sigismember(&t->real_blocked, sig) &&
1042 (sig == SIGKILL || !p->ptrace)) {
1044 * This signal will be fatal to the whole group.
1046 if (!sig_kernel_coredump(sig)) {
1048 * Start a group exit and wake everybody up.
1049 * This way we don't have other threads
1050 * running and doing things after a slower
1051 * thread has the fatal signal pending.
1053 signal->flags = SIGNAL_GROUP_EXIT;
1054 signal->group_exit_code = sig;
1055 signal->group_stop_count = 0;
1058 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1059 sigaddset(&t->pending.signal, SIGKILL);
1060 signal_wake_up(t, 1);
1061 } while_each_thread(p, t);
1067 * The signal is already in the shared-pending queue.
1068 * Tell the chosen thread to wake up and dequeue it.
1070 signal_wake_up(t, sig == SIGKILL);
1074 static inline bool legacy_queue(struct sigpending *signals, int sig)
1076 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1079 static int __send_signal_locked(int sig, struct kernel_siginfo *info,
1080 struct task_struct *t, enum pid_type type, bool force)
1082 struct sigpending *pending;
1084 int override_rlimit;
1085 int ret = 0, result;
1087 lockdep_assert_held(&t->sighand->siglock);
1089 result = TRACE_SIGNAL_IGNORED;
1090 if (!prepare_signal(sig, t, force))
1093 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1095 * Short-circuit ignored signals and support queuing
1096 * exactly one non-rt signal, so that we can get more
1097 * detailed information about the cause of the signal.
1099 result = TRACE_SIGNAL_ALREADY_PENDING;
1100 if (legacy_queue(pending, sig))
1103 result = TRACE_SIGNAL_DELIVERED;
1105 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1107 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1111 * Real-time signals must be queued if sent by sigqueue, or
1112 * some other real-time mechanism. It is implementation
1113 * defined whether kill() does so. We attempt to do so, on
1114 * the principle of least surprise, but since kill is not
1115 * allowed to fail with EAGAIN when low on memory we just
1116 * make sure at least one signal gets delivered and don't
1117 * pass on the info struct.
1120 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1122 override_rlimit = 0;
1124 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
1127 list_add_tail(&q->list, &pending->list);
1128 switch ((unsigned long) info) {
1129 case (unsigned long) SEND_SIG_NOINFO:
1130 clear_siginfo(&q->info);
1131 q->info.si_signo = sig;
1132 q->info.si_errno = 0;
1133 q->info.si_code = SI_USER;
1134 q->info.si_pid = task_tgid_nr_ns(current,
1135 task_active_pid_ns(t));
1138 from_kuid_munged(task_cred_xxx(t, user_ns),
1142 case (unsigned long) SEND_SIG_PRIV:
1143 clear_siginfo(&q->info);
1144 q->info.si_signo = sig;
1145 q->info.si_errno = 0;
1146 q->info.si_code = SI_KERNEL;
1151 copy_siginfo(&q->info, info);
1154 } else if (!is_si_special(info) &&
1155 sig >= SIGRTMIN && info->si_code != SI_USER) {
1157 * Queue overflow, abort. We may abort if the
1158 * signal was rt and sent by user using something
1159 * other than kill().
1161 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1166 * This is a silent loss of information. We still
1167 * send the signal, but the *info bits are lost.
1169 result = TRACE_SIGNAL_LOSE_INFO;
1173 signalfd_notify(t, sig);
1174 sigaddset(&pending->signal, sig);
1176 /* Let multiprocess signals appear after on-going forks */
1177 if (type > PIDTYPE_TGID) {
1178 struct multiprocess_signals *delayed;
1179 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1180 sigset_t *signal = &delayed->signal;
1181 /* Can't queue both a stop and a continue signal */
1183 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1184 else if (sig_kernel_stop(sig))
1185 sigdelset(signal, SIGCONT);
1186 sigaddset(signal, sig);
1190 complete_signal(sig, t, type);
1192 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1196 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1199 switch (siginfo_layout(info->si_signo, info->si_code)) {
1208 case SIL_FAULT_TRAPNO:
1209 case SIL_FAULT_MCEERR:
1210 case SIL_FAULT_BNDERR:
1211 case SIL_FAULT_PKUERR:
1212 case SIL_FAULT_PERF_EVENT:
1220 int send_signal_locked(int sig, struct kernel_siginfo *info,
1221 struct task_struct *t, enum pid_type type)
1223 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1226 if (info == SEND_SIG_NOINFO) {
1227 /* Force if sent from an ancestor pid namespace */
1228 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1229 } else if (info == SEND_SIG_PRIV) {
1230 /* Don't ignore kernel generated signals */
1232 } else if (has_si_pid_and_uid(info)) {
1233 /* SIGKILL and SIGSTOP is special or has ids */
1234 struct user_namespace *t_user_ns;
1237 t_user_ns = task_cred_xxx(t, user_ns);
1238 if (current_user_ns() != t_user_ns) {
1239 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1240 info->si_uid = from_kuid_munged(t_user_ns, uid);
1244 /* A kernel generated signal? */
1245 force = (info->si_code == SI_KERNEL);
1247 /* From an ancestor pid namespace? */
1248 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1253 return __send_signal_locked(sig, info, t, type, force);
1256 static void print_fatal_signal(int signr)
1258 struct pt_regs *regs = task_pt_regs(current);
1259 pr_info("potentially unexpected fatal signal %d.\n", signr);
1261 #if defined(__i386__) && !defined(__arch_um__)
1262 pr_info("code at %08lx: ", regs->ip);
1265 for (i = 0; i < 16; i++) {
1268 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1270 pr_cont("%02x ", insn);
1280 static int __init setup_print_fatal_signals(char *str)
1282 get_option (&str, &print_fatal_signals);
1287 __setup("print-fatal-signals=", setup_print_fatal_signals);
1289 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1292 unsigned long flags;
1295 if (lock_task_sighand(p, &flags)) {
1296 ret = send_signal_locked(sig, info, p, type);
1297 unlock_task_sighand(p, &flags);
1304 HANDLER_CURRENT, /* If reachable use the current handler */
1305 HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */
1306 HANDLER_EXIT, /* Only visible as the process exit code */
1310 * Force a signal that the process can't ignore: if necessary
1311 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1313 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1314 * since we do not want to have a signal handler that was blocked
1315 * be invoked when user space had explicitly blocked it.
1317 * We don't want to have recursive SIGSEGV's etc, for example,
1318 * that is why we also clear SIGNAL_UNKILLABLE.
1321 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
1322 enum sig_handler handler)
1324 unsigned long int flags;
1325 int ret, blocked, ignored;
1326 struct k_sigaction *action;
1327 int sig = info->si_signo;
1329 spin_lock_irqsave(&t->sighand->siglock, flags);
1330 action = &t->sighand->action[sig-1];
1331 ignored = action->sa.sa_handler == SIG_IGN;
1332 blocked = sigismember(&t->blocked, sig);
1333 if (blocked || ignored || (handler != HANDLER_CURRENT)) {
1334 action->sa.sa_handler = SIG_DFL;
1335 if (handler == HANDLER_EXIT)
1336 action->sa.sa_flags |= SA_IMMUTABLE;
1338 sigdelset(&t->blocked, sig);
1339 recalc_sigpending_and_wake(t);
1343 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1344 * debugging to leave init killable. But HANDLER_EXIT is always fatal.
1346 if (action->sa.sa_handler == SIG_DFL &&
1347 (!t->ptrace || (handler == HANDLER_EXIT)))
1348 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1349 ret = send_signal_locked(sig, info, t, PIDTYPE_PID);
1350 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1355 int force_sig_info(struct kernel_siginfo *info)
1357 return force_sig_info_to_task(info, current, HANDLER_CURRENT);
1361 * Nuke all other threads in the group.
1363 int zap_other_threads(struct task_struct *p)
1365 struct task_struct *t = p;
1368 p->signal->group_stop_count = 0;
1370 while_each_thread(p, t) {
1371 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1374 /* Don't bother with already dead threads */
1377 sigaddset(&t->pending.signal, SIGKILL);
1378 signal_wake_up(t, 1);
1384 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1385 unsigned long *flags)
1387 struct sighand_struct *sighand;
1391 sighand = rcu_dereference(tsk->sighand);
1392 if (unlikely(sighand == NULL))
1396 * This sighand can be already freed and even reused, but
1397 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1398 * initializes ->siglock: this slab can't go away, it has
1399 * the same object type, ->siglock can't be reinitialized.
1401 * We need to ensure that tsk->sighand is still the same
1402 * after we take the lock, we can race with de_thread() or
1403 * __exit_signal(). In the latter case the next iteration
1404 * must see ->sighand == NULL.
1406 spin_lock_irqsave(&sighand->siglock, *flags);
1407 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1409 spin_unlock_irqrestore(&sighand->siglock, *flags);
1416 #ifdef CONFIG_LOCKDEP
1417 void lockdep_assert_task_sighand_held(struct task_struct *task)
1419 struct sighand_struct *sighand;
1422 sighand = rcu_dereference(task->sighand);
1424 lockdep_assert_held(&sighand->siglock);
1432 * send signal info to all the members of a group
1434 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1435 struct task_struct *p, enum pid_type type)
1440 ret = check_kill_permission(sig, info, p);
1444 ret = do_send_sig_info(sig, info, p, type);
1450 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1451 * control characters do (^C, ^Z etc)
1452 * - the caller must hold at least a readlock on tasklist_lock
1454 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1456 struct task_struct *p = NULL;
1457 int retval, success;
1461 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1462 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1465 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1466 return success ? 0 : retval;
1469 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1472 struct task_struct *p;
1476 p = pid_task(pid, PIDTYPE_PID);
1478 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1480 if (likely(!p || error != -ESRCH))
1484 * The task was unhashed in between, try again. If it
1485 * is dead, pid_task() will return NULL, if we race with
1486 * de_thread() it will find the new leader.
1491 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1495 error = kill_pid_info(sig, info, find_vpid(pid));
1500 static inline bool kill_as_cred_perm(const struct cred *cred,
1501 struct task_struct *target)
1503 const struct cred *pcred = __task_cred(target);
1505 return uid_eq(cred->euid, pcred->suid) ||
1506 uid_eq(cred->euid, pcred->uid) ||
1507 uid_eq(cred->uid, pcred->suid) ||
1508 uid_eq(cred->uid, pcred->uid);
1512 * The usb asyncio usage of siginfo is wrong. The glibc support
1513 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1514 * AKA after the generic fields:
1515 * kernel_pid_t si_pid;
1516 * kernel_uid32_t si_uid;
1517 * sigval_t si_value;
1519 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1520 * after the generic fields is:
1521 * void __user *si_addr;
1523 * This is a practical problem when there is a 64bit big endian kernel
1524 * and a 32bit userspace. As the 32bit address will encoded in the low
1525 * 32bits of the pointer. Those low 32bits will be stored at higher
1526 * address than appear in a 32 bit pointer. So userspace will not
1527 * see the address it was expecting for it's completions.
1529 * There is nothing in the encoding that can allow
1530 * copy_siginfo_to_user32 to detect this confusion of formats, so
1531 * handle this by requiring the caller of kill_pid_usb_asyncio to
1532 * notice when this situration takes place and to store the 32bit
1533 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1536 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1537 struct pid *pid, const struct cred *cred)
1539 struct kernel_siginfo info;
1540 struct task_struct *p;
1541 unsigned long flags;
1544 if (!valid_signal(sig))
1547 clear_siginfo(&info);
1548 info.si_signo = sig;
1549 info.si_errno = errno;
1550 info.si_code = SI_ASYNCIO;
1551 *((sigval_t *)&info.si_pid) = addr;
1554 p = pid_task(pid, PIDTYPE_PID);
1559 if (!kill_as_cred_perm(cred, p)) {
1563 ret = security_task_kill(p, &info, sig, cred);
1568 if (lock_task_sighand(p, &flags)) {
1569 ret = __send_signal_locked(sig, &info, p, PIDTYPE_TGID, false);
1570 unlock_task_sighand(p, &flags);
1578 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1581 * kill_something_info() interprets pid in interesting ways just like kill(2).
1583 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1584 * is probably wrong. Should make it like BSD or SYSV.
1587 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1592 return kill_proc_info(sig, info, pid);
1594 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1598 read_lock(&tasklist_lock);
1600 ret = __kill_pgrp_info(sig, info,
1601 pid ? find_vpid(-pid) : task_pgrp(current));
1603 int retval = 0, count = 0;
1604 struct task_struct * p;
1606 for_each_process(p) {
1607 if (task_pid_vnr(p) > 1 &&
1608 !same_thread_group(p, current)) {
1609 int err = group_send_sig_info(sig, info, p,
1616 ret = count ? retval : -ESRCH;
1618 read_unlock(&tasklist_lock);
1624 * These are for backward compatibility with the rest of the kernel source.
1627 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1630 * Make sure legacy kernel users don't send in bad values
1631 * (normal paths check this in check_kill_permission).
1633 if (!valid_signal(sig))
1636 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1638 EXPORT_SYMBOL(send_sig_info);
1640 #define __si_special(priv) \
1641 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1644 send_sig(int sig, struct task_struct *p, int priv)
1646 return send_sig_info(sig, __si_special(priv), p);
1648 EXPORT_SYMBOL(send_sig);
1650 void force_sig(int sig)
1652 struct kernel_siginfo info;
1654 clear_siginfo(&info);
1655 info.si_signo = sig;
1657 info.si_code = SI_KERNEL;
1660 force_sig_info(&info);
1662 EXPORT_SYMBOL(force_sig);
1664 void force_fatal_sig(int sig)
1666 struct kernel_siginfo info;
1668 clear_siginfo(&info);
1669 info.si_signo = sig;
1671 info.si_code = SI_KERNEL;
1674 force_sig_info_to_task(&info, current, HANDLER_SIG_DFL);
1677 void force_exit_sig(int sig)
1679 struct kernel_siginfo info;
1681 clear_siginfo(&info);
1682 info.si_signo = sig;
1684 info.si_code = SI_KERNEL;
1687 force_sig_info_to_task(&info, current, HANDLER_EXIT);
1691 * When things go south during signal handling, we
1692 * will force a SIGSEGV. And if the signal that caused
1693 * the problem was already a SIGSEGV, we'll want to
1694 * make sure we don't even try to deliver the signal..
1696 void force_sigsegv(int sig)
1699 force_fatal_sig(SIGSEGV);
1704 int force_sig_fault_to_task(int sig, int code, void __user *addr
1705 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1706 , struct task_struct *t)
1708 struct kernel_siginfo info;
1710 clear_siginfo(&info);
1711 info.si_signo = sig;
1713 info.si_code = code;
1714 info.si_addr = addr;
1717 info.si_flags = flags;
1720 return force_sig_info_to_task(&info, t, HANDLER_CURRENT);
1723 int force_sig_fault(int sig, int code, void __user *addr
1724 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1726 return force_sig_fault_to_task(sig, code, addr
1727 ___ARCH_SI_IA64(imm, flags, isr), current);
1730 int send_sig_fault(int sig, int code, void __user *addr
1731 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1732 , struct task_struct *t)
1734 struct kernel_siginfo info;
1736 clear_siginfo(&info);
1737 info.si_signo = sig;
1739 info.si_code = code;
1740 info.si_addr = addr;
1743 info.si_flags = flags;
1746 return send_sig_info(info.si_signo, &info, t);
1749 int force_sig_mceerr(int code, void __user *addr, short lsb)
1751 struct kernel_siginfo info;
1753 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1754 clear_siginfo(&info);
1755 info.si_signo = SIGBUS;
1757 info.si_code = code;
1758 info.si_addr = addr;
1759 info.si_addr_lsb = lsb;
1760 return force_sig_info(&info);
1763 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1765 struct kernel_siginfo info;
1767 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1768 clear_siginfo(&info);
1769 info.si_signo = SIGBUS;
1771 info.si_code = code;
1772 info.si_addr = addr;
1773 info.si_addr_lsb = lsb;
1774 return send_sig_info(info.si_signo, &info, t);
1776 EXPORT_SYMBOL(send_sig_mceerr);
1778 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1780 struct kernel_siginfo info;
1782 clear_siginfo(&info);
1783 info.si_signo = SIGSEGV;
1785 info.si_code = SEGV_BNDERR;
1786 info.si_addr = addr;
1787 info.si_lower = lower;
1788 info.si_upper = upper;
1789 return force_sig_info(&info);
1793 int force_sig_pkuerr(void __user *addr, u32 pkey)
1795 struct kernel_siginfo info;
1797 clear_siginfo(&info);
1798 info.si_signo = SIGSEGV;
1800 info.si_code = SEGV_PKUERR;
1801 info.si_addr = addr;
1802 info.si_pkey = pkey;
1803 return force_sig_info(&info);
1807 int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
1809 struct kernel_siginfo info;
1811 clear_siginfo(&info);
1812 info.si_signo = SIGTRAP;
1814 info.si_code = TRAP_PERF;
1815 info.si_addr = addr;
1816 info.si_perf_data = sig_data;
1817 info.si_perf_type = type;
1820 * Signals generated by perf events should not terminate the whole
1821 * process if SIGTRAP is blocked, however, delivering the signal
1822 * asynchronously is better than not delivering at all. But tell user
1823 * space if the signal was asynchronous, so it can clearly be
1824 * distinguished from normal synchronous ones.
1826 info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ?
1827 TRAP_PERF_FLAG_ASYNC :
1830 return send_sig_info(info.si_signo, &info, current);
1834 * force_sig_seccomp - signals the task to allow in-process syscall emulation
1835 * @syscall: syscall number to send to userland
1836 * @reason: filter-supplied reason code to send to userland (via si_errno)
1837 * @force_coredump: true to trigger a coredump
1839 * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
1841 int force_sig_seccomp(int syscall, int reason, bool force_coredump)
1843 struct kernel_siginfo info;
1845 clear_siginfo(&info);
1846 info.si_signo = SIGSYS;
1847 info.si_code = SYS_SECCOMP;
1848 info.si_call_addr = (void __user *)KSTK_EIP(current);
1849 info.si_errno = reason;
1850 info.si_arch = syscall_get_arch(current);
1851 info.si_syscall = syscall;
1852 return force_sig_info_to_task(&info, current,
1853 force_coredump ? HANDLER_EXIT : HANDLER_CURRENT);
1856 /* For the crazy architectures that include trap information in
1857 * the errno field, instead of an actual errno value.
1859 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1861 struct kernel_siginfo info;
1863 clear_siginfo(&info);
1864 info.si_signo = SIGTRAP;
1865 info.si_errno = errno;
1866 info.si_code = TRAP_HWBKPT;
1867 info.si_addr = addr;
1868 return force_sig_info(&info);
1871 /* For the rare architectures that include trap information using
1874 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
1876 struct kernel_siginfo info;
1878 clear_siginfo(&info);
1879 info.si_signo = sig;
1881 info.si_code = code;
1882 info.si_addr = addr;
1883 info.si_trapno = trapno;
1884 return force_sig_info(&info);
1887 /* For the rare architectures that include trap information using
1890 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
1891 struct task_struct *t)
1893 struct kernel_siginfo info;
1895 clear_siginfo(&info);
1896 info.si_signo = sig;
1898 info.si_code = code;
1899 info.si_addr = addr;
1900 info.si_trapno = trapno;
1901 return send_sig_info(info.si_signo, &info, t);
1904 int kill_pgrp(struct pid *pid, int sig, int priv)
1908 read_lock(&tasklist_lock);
1909 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1910 read_unlock(&tasklist_lock);
1914 EXPORT_SYMBOL(kill_pgrp);
1916 int kill_pid(struct pid *pid, int sig, int priv)
1918 return kill_pid_info(sig, __si_special(priv), pid);
1920 EXPORT_SYMBOL(kill_pid);
1923 * These functions support sending signals using preallocated sigqueue
1924 * structures. This is needed "because realtime applications cannot
1925 * afford to lose notifications of asynchronous events, like timer
1926 * expirations or I/O completions". In the case of POSIX Timers
1927 * we allocate the sigqueue structure from the timer_create. If this
1928 * allocation fails we are able to report the failure to the application
1929 * with an EAGAIN error.
1931 struct sigqueue *sigqueue_alloc(void)
1933 return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
1936 void sigqueue_free(struct sigqueue *q)
1938 unsigned long flags;
1939 spinlock_t *lock = ¤t->sighand->siglock;
1941 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1943 * We must hold ->siglock while testing q->list
1944 * to serialize with collect_signal() or with
1945 * __exit_signal()->flush_sigqueue().
1947 spin_lock_irqsave(lock, flags);
1948 q->flags &= ~SIGQUEUE_PREALLOC;
1950 * If it is queued it will be freed when dequeued,
1951 * like the "regular" sigqueue.
1953 if (!list_empty(&q->list))
1955 spin_unlock_irqrestore(lock, flags);
1961 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1963 int sig = q->info.si_signo;
1964 struct sigpending *pending;
1965 struct task_struct *t;
1966 unsigned long flags;
1969 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1973 t = pid_task(pid, type);
1974 if (!t || !likely(lock_task_sighand(t, &flags)))
1977 ret = 1; /* the signal is ignored */
1978 result = TRACE_SIGNAL_IGNORED;
1979 if (!prepare_signal(sig, t, false))
1983 if (unlikely(!list_empty(&q->list))) {
1985 * If an SI_TIMER entry is already queue just increment
1986 * the overrun count.
1988 BUG_ON(q->info.si_code != SI_TIMER);
1989 q->info.si_overrun++;
1990 result = TRACE_SIGNAL_ALREADY_PENDING;
1993 q->info.si_overrun = 0;
1995 signalfd_notify(t, sig);
1996 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1997 list_add_tail(&q->list, &pending->list);
1998 sigaddset(&pending->signal, sig);
1999 complete_signal(sig, t, type);
2000 result = TRACE_SIGNAL_DELIVERED;
2002 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
2003 unlock_task_sighand(t, &flags);
2009 static void do_notify_pidfd(struct task_struct *task)
2013 WARN_ON(task->exit_state == 0);
2014 pid = task_pid(task);
2015 wake_up_all(&pid->wait_pidfd);
2019 * Let a parent know about the death of a child.
2020 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
2022 * Returns true if our parent ignored us and so we've switched to
2025 bool do_notify_parent(struct task_struct *tsk, int sig)
2027 struct kernel_siginfo info;
2028 unsigned long flags;
2029 struct sighand_struct *psig;
2030 bool autoreap = false;
2033 WARN_ON_ONCE(sig == -1);
2035 /* do_notify_parent_cldstop should have been called instead. */
2036 WARN_ON_ONCE(task_is_stopped_or_traced(tsk));
2038 WARN_ON_ONCE(!tsk->ptrace &&
2039 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
2041 /* Wake up all pidfd waiters */
2042 do_notify_pidfd(tsk);
2044 if (sig != SIGCHLD) {
2046 * This is only possible if parent == real_parent.
2047 * Check if it has changed security domain.
2049 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
2053 clear_siginfo(&info);
2054 info.si_signo = sig;
2057 * We are under tasklist_lock here so our parent is tied to
2058 * us and cannot change.
2060 * task_active_pid_ns will always return the same pid namespace
2061 * until a task passes through release_task.
2063 * write_lock() currently calls preempt_disable() which is the
2064 * same as rcu_read_lock(), but according to Oleg, this is not
2065 * correct to rely on this
2068 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
2069 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
2073 task_cputime(tsk, &utime, &stime);
2074 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
2075 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
2077 info.si_status = tsk->exit_code & 0x7f;
2078 if (tsk->exit_code & 0x80)
2079 info.si_code = CLD_DUMPED;
2080 else if (tsk->exit_code & 0x7f)
2081 info.si_code = CLD_KILLED;
2083 info.si_code = CLD_EXITED;
2084 info.si_status = tsk->exit_code >> 8;
2087 psig = tsk->parent->sighand;
2088 spin_lock_irqsave(&psig->siglock, flags);
2089 if (!tsk->ptrace && sig == SIGCHLD &&
2090 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
2091 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
2093 * We are exiting and our parent doesn't care. POSIX.1
2094 * defines special semantics for setting SIGCHLD to SIG_IGN
2095 * or setting the SA_NOCLDWAIT flag: we should be reaped
2096 * automatically and not left for our parent's wait4 call.
2097 * Rather than having the parent do it as a magic kind of
2098 * signal handler, we just set this to tell do_exit that we
2099 * can be cleaned up without becoming a zombie. Note that
2100 * we still call __wake_up_parent in this case, because a
2101 * blocked sys_wait4 might now return -ECHILD.
2103 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
2104 * is implementation-defined: we do (if you don't want
2105 * it, just use SIG_IGN instead).
2108 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
2112 * Send with __send_signal as si_pid and si_uid are in the
2113 * parent's namespaces.
2115 if (valid_signal(sig) && sig)
2116 __send_signal_locked(sig, &info, tsk->parent, PIDTYPE_TGID, false);
2117 __wake_up_parent(tsk, tsk->parent);
2118 spin_unlock_irqrestore(&psig->siglock, flags);
2124 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2125 * @tsk: task reporting the state change
2126 * @for_ptracer: the notification is for ptracer
2127 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2129 * Notify @tsk's parent that the stopped/continued state has changed. If
2130 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2131 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2134 * Must be called with tasklist_lock at least read locked.
2136 static void do_notify_parent_cldstop(struct task_struct *tsk,
2137 bool for_ptracer, int why)
2139 struct kernel_siginfo info;
2140 unsigned long flags;
2141 struct task_struct *parent;
2142 struct sighand_struct *sighand;
2146 parent = tsk->parent;
2148 tsk = tsk->group_leader;
2149 parent = tsk->real_parent;
2152 clear_siginfo(&info);
2153 info.si_signo = SIGCHLD;
2156 * see comment in do_notify_parent() about the following 4 lines
2159 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2160 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2163 task_cputime(tsk, &utime, &stime);
2164 info.si_utime = nsec_to_clock_t(utime);
2165 info.si_stime = nsec_to_clock_t(stime);
2170 info.si_status = SIGCONT;
2173 info.si_status = tsk->signal->group_exit_code & 0x7f;
2176 info.si_status = tsk->exit_code & 0x7f;
2182 sighand = parent->sighand;
2183 spin_lock_irqsave(&sighand->siglock, flags);
2184 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2185 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2186 send_signal_locked(SIGCHLD, &info, parent, PIDTYPE_TGID);
2188 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2190 __wake_up_parent(tsk, parent);
2191 spin_unlock_irqrestore(&sighand->siglock, flags);
2195 * This must be called with current->sighand->siglock held.
2197 * This should be the path for all ptrace stops.
2198 * We always set current->last_siginfo while stopped here.
2199 * That makes it a way to test a stopped process for
2200 * being ptrace-stopped vs being job-control-stopped.
2202 * Returns the signal the ptracer requested the code resume
2203 * with. If the code did not stop because the tracer is gone,
2204 * the stop signal remains unchanged unless clear_code.
2206 static int ptrace_stop(int exit_code, int why, unsigned long message,
2207 kernel_siginfo_t *info)
2208 __releases(¤t->sighand->siglock)
2209 __acquires(¤t->sighand->siglock)
2211 bool gstop_done = false;
2213 if (arch_ptrace_stop_needed()) {
2215 * The arch code has something special to do before a
2216 * ptrace stop. This is allowed to block, e.g. for faults
2217 * on user stack pages. We can't keep the siglock while
2218 * calling arch_ptrace_stop, so we must release it now.
2219 * To preserve proper semantics, we must do this before
2220 * any signal bookkeeping like checking group_stop_count.
2222 spin_unlock_irq(¤t->sighand->siglock);
2224 spin_lock_irq(¤t->sighand->siglock);
2228 * After this point ptrace_signal_wake_up or signal_wake_up
2229 * will clear TASK_TRACED if ptrace_unlink happens or a fatal
2230 * signal comes in. Handle previous ptrace_unlinks and fatal
2231 * signals here to prevent ptrace_stop sleeping in schedule.
2233 if (!current->ptrace || __fatal_signal_pending(current))
2236 set_special_state(TASK_TRACED);
2237 current->jobctl |= JOBCTL_TRACED;
2240 * We're committing to trapping. TRACED should be visible before
2241 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2242 * Also, transition to TRACED and updates to ->jobctl should be
2243 * atomic with respect to siglock and should be done after the arch
2244 * hook as siglock is released and regrabbed across it.
2249 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2251 * set_current_state() smp_wmb();
2253 * wait_task_stopped()
2254 * task_stopped_code()
2255 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2259 current->ptrace_message = message;
2260 current->last_siginfo = info;
2261 current->exit_code = exit_code;
2264 * If @why is CLD_STOPPED, we're trapping to participate in a group
2265 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2266 * across siglock relocks since INTERRUPT was scheduled, PENDING
2267 * could be clear now. We act as if SIGCONT is received after
2268 * TASK_TRACED is entered - ignore it.
2270 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2271 gstop_done = task_participate_group_stop(current);
2273 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2274 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2275 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2276 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2278 /* entering a trap, clear TRAPPING */
2279 task_clear_jobctl_trapping(current);
2281 spin_unlock_irq(¤t->sighand->siglock);
2282 read_lock(&tasklist_lock);
2284 * Notify parents of the stop.
2286 * While ptraced, there are two parents - the ptracer and
2287 * the real_parent of the group_leader. The ptracer should
2288 * know about every stop while the real parent is only
2289 * interested in the completion of group stop. The states
2290 * for the two don't interact with each other. Notify
2291 * separately unless they're gonna be duplicates.
2293 if (current->ptrace)
2294 do_notify_parent_cldstop(current, true, why);
2295 if (gstop_done && (!current->ptrace || ptrace_reparented(current)))
2296 do_notify_parent_cldstop(current, false, why);
2299 * Don't want to allow preemption here, because
2300 * sys_ptrace() needs this task to be inactive.
2302 * XXX: implement read_unlock_no_resched().
2305 read_unlock(&tasklist_lock);
2306 cgroup_enter_frozen();
2307 preempt_enable_no_resched();
2309 cgroup_leave_frozen(true);
2312 * We are back. Now reacquire the siglock before touching
2313 * last_siginfo, so that we are sure to have synchronized with
2314 * any signal-sending on another CPU that wants to examine it.
2316 spin_lock_irq(¤t->sighand->siglock);
2317 exit_code = current->exit_code;
2318 current->last_siginfo = NULL;
2319 current->ptrace_message = 0;
2320 current->exit_code = 0;
2322 /* LISTENING can be set only during STOP traps, clear it */
2323 current->jobctl &= ~(JOBCTL_LISTENING | JOBCTL_PTRACE_FROZEN);
2326 * Queued signals ignored us while we were stopped for tracing.
2327 * So check for any that we should take before resuming user mode.
2328 * This sets TIF_SIGPENDING, but never clears it.
2330 recalc_sigpending_tsk(current);
2334 static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message)
2336 kernel_siginfo_t info;
2338 clear_siginfo(&info);
2339 info.si_signo = signr;
2340 info.si_code = exit_code;
2341 info.si_pid = task_pid_vnr(current);
2342 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2344 /* Let the debugger run. */
2345 return ptrace_stop(exit_code, why, message, &info);
2348 int ptrace_notify(int exit_code, unsigned long message)
2352 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2353 if (unlikely(task_work_pending(current)))
2356 spin_lock_irq(¤t->sighand->siglock);
2357 signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message);
2358 spin_unlock_irq(¤t->sighand->siglock);
2363 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2364 * @signr: signr causing group stop if initiating
2366 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2367 * and participate in it. If already set, participate in the existing
2368 * group stop. If participated in a group stop (and thus slept), %true is
2369 * returned with siglock released.
2371 * If ptraced, this function doesn't handle stop itself. Instead,
2372 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2373 * untouched. The caller must ensure that INTERRUPT trap handling takes
2374 * places afterwards.
2377 * Must be called with @current->sighand->siglock held, which is released
2381 * %false if group stop is already cancelled or ptrace trap is scheduled.
2382 * %true if participated in group stop.
2384 static bool do_signal_stop(int signr)
2385 __releases(¤t->sighand->siglock)
2387 struct signal_struct *sig = current->signal;
2389 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2390 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2391 struct task_struct *t;
2393 /* signr will be recorded in task->jobctl for retries */
2394 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2396 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2397 unlikely(sig->flags & SIGNAL_GROUP_EXIT) ||
2398 unlikely(sig->group_exec_task))
2401 * There is no group stop already in progress. We must
2404 * While ptraced, a task may be resumed while group stop is
2405 * still in effect and then receive a stop signal and
2406 * initiate another group stop. This deviates from the
2407 * usual behavior as two consecutive stop signals can't
2408 * cause two group stops when !ptraced. That is why we
2409 * also check !task_is_stopped(t) below.
2411 * The condition can be distinguished by testing whether
2412 * SIGNAL_STOP_STOPPED is already set. Don't generate
2413 * group_exit_code in such case.
2415 * This is not necessary for SIGNAL_STOP_CONTINUED because
2416 * an intervening stop signal is required to cause two
2417 * continued events regardless of ptrace.
2419 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2420 sig->group_exit_code = signr;
2422 sig->group_stop_count = 0;
2424 if (task_set_jobctl_pending(current, signr | gstop))
2425 sig->group_stop_count++;
2428 while_each_thread(current, t) {
2430 * Setting state to TASK_STOPPED for a group
2431 * stop is always done with the siglock held,
2432 * so this check has no races.
2434 if (!task_is_stopped(t) &&
2435 task_set_jobctl_pending(t, signr | gstop)) {
2436 sig->group_stop_count++;
2437 if (likely(!(t->ptrace & PT_SEIZED)))
2438 signal_wake_up(t, 0);
2440 ptrace_trap_notify(t);
2445 if (likely(!current->ptrace)) {
2449 * If there are no other threads in the group, or if there
2450 * is a group stop in progress and we are the last to stop,
2451 * report to the parent.
2453 if (task_participate_group_stop(current))
2454 notify = CLD_STOPPED;
2456 current->jobctl |= JOBCTL_STOPPED;
2457 set_special_state(TASK_STOPPED);
2458 spin_unlock_irq(¤t->sighand->siglock);
2461 * Notify the parent of the group stop completion. Because
2462 * we're not holding either the siglock or tasklist_lock
2463 * here, ptracer may attach inbetween; however, this is for
2464 * group stop and should always be delivered to the real
2465 * parent of the group leader. The new ptracer will get
2466 * its notification when this task transitions into
2470 read_lock(&tasklist_lock);
2471 do_notify_parent_cldstop(current, false, notify);
2472 read_unlock(&tasklist_lock);
2475 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2476 cgroup_enter_frozen();
2481 * While ptraced, group stop is handled by STOP trap.
2482 * Schedule it and let the caller deal with it.
2484 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2490 * do_jobctl_trap - take care of ptrace jobctl traps
2492 * When PT_SEIZED, it's used for both group stop and explicit
2493 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2494 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2495 * the stop signal; otherwise, %SIGTRAP.
2497 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2498 * number as exit_code and no siginfo.
2501 * Must be called with @current->sighand->siglock held, which may be
2502 * released and re-acquired before returning with intervening sleep.
2504 static void do_jobctl_trap(void)
2506 struct signal_struct *signal = current->signal;
2507 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2509 if (current->ptrace & PT_SEIZED) {
2510 if (!signal->group_stop_count &&
2511 !(signal->flags & SIGNAL_STOP_STOPPED))
2513 WARN_ON_ONCE(!signr);
2514 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2517 WARN_ON_ONCE(!signr);
2518 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2523 * do_freezer_trap - handle the freezer jobctl trap
2525 * Puts the task into frozen state, if only the task is not about to quit.
2526 * In this case it drops JOBCTL_TRAP_FREEZE.
2529 * Must be called with @current->sighand->siglock held,
2530 * which is always released before returning.
2532 static void do_freezer_trap(void)
2533 __releases(¤t->sighand->siglock)
2536 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2537 * let's make another loop to give it a chance to be handled.
2538 * In any case, we'll return back.
2540 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2541 JOBCTL_TRAP_FREEZE) {
2542 spin_unlock_irq(¤t->sighand->siglock);
2547 * Now we're sure that there is no pending fatal signal and no
2548 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2549 * immediately (if there is a non-fatal signal pending), and
2550 * put the task into sleep.
2552 __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
2553 clear_thread_flag(TIF_SIGPENDING);
2554 spin_unlock_irq(¤t->sighand->siglock);
2555 cgroup_enter_frozen();
2559 static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type)
2562 * We do not check sig_kernel_stop(signr) but set this marker
2563 * unconditionally because we do not know whether debugger will
2564 * change signr. This flag has no meaning unless we are going
2565 * to stop after return from ptrace_stop(). In this case it will
2566 * be checked in do_signal_stop(), we should only stop if it was
2567 * not cleared by SIGCONT while we were sleeping. See also the
2568 * comment in dequeue_signal().
2570 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2571 signr = ptrace_stop(signr, CLD_TRAPPED, 0, info);
2573 /* We're back. Did the debugger cancel the sig? */
2578 * Update the siginfo structure if the signal has
2579 * changed. If the debugger wanted something
2580 * specific in the siginfo structure then it should
2581 * have updated *info via PTRACE_SETSIGINFO.
2583 if (signr != info->si_signo) {
2584 clear_siginfo(info);
2585 info->si_signo = signr;
2587 info->si_code = SI_USER;
2589 info->si_pid = task_pid_vnr(current->parent);
2590 info->si_uid = from_kuid_munged(current_user_ns(),
2591 task_uid(current->parent));
2595 /* If the (new) signal is now blocked, requeue it. */
2596 if (sigismember(¤t->blocked, signr) ||
2597 fatal_signal_pending(current)) {
2598 send_signal_locked(signr, info, current, type);
2605 static void hide_si_addr_tag_bits(struct ksignal *ksig)
2607 switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
2609 case SIL_FAULT_TRAPNO:
2610 case SIL_FAULT_MCEERR:
2611 case SIL_FAULT_BNDERR:
2612 case SIL_FAULT_PKUERR:
2613 case SIL_FAULT_PERF_EVENT:
2614 ksig->info.si_addr = arch_untagged_si_addr(
2615 ksig->info.si_addr, ksig->sig, ksig->info.si_code);
2627 bool get_signal(struct ksignal *ksig)
2629 struct sighand_struct *sighand = current->sighand;
2630 struct signal_struct *signal = current->signal;
2633 clear_notify_signal();
2634 if (unlikely(task_work_pending(current)))
2637 if (!task_sigpending(current))
2640 if (unlikely(uprobe_deny_signal()))
2644 * Do this once, we can't return to user-mode if freezing() == T.
2645 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2646 * thus do not need another check after return.
2651 spin_lock_irq(&sighand->siglock);
2654 * Every stopped thread goes here after wakeup. Check to see if
2655 * we should notify the parent, prepare_signal(SIGCONT) encodes
2656 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2658 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2661 if (signal->flags & SIGNAL_CLD_CONTINUED)
2662 why = CLD_CONTINUED;
2666 signal->flags &= ~SIGNAL_CLD_MASK;
2668 spin_unlock_irq(&sighand->siglock);
2671 * Notify the parent that we're continuing. This event is
2672 * always per-process and doesn't make whole lot of sense
2673 * for ptracers, who shouldn't consume the state via
2674 * wait(2) either, but, for backward compatibility, notify
2675 * the ptracer of the group leader too unless it's gonna be
2678 read_lock(&tasklist_lock);
2679 do_notify_parent_cldstop(current, false, why);
2681 if (ptrace_reparented(current->group_leader))
2682 do_notify_parent_cldstop(current->group_leader,
2684 read_unlock(&tasklist_lock);
2690 struct k_sigaction *ka;
2693 /* Has this task already been marked for death? */
2694 if ((signal->flags & SIGNAL_GROUP_EXIT) ||
2695 signal->group_exec_task) {
2696 clear_siginfo(&ksig->info);
2697 ksig->info.si_signo = signr = SIGKILL;
2698 sigdelset(¤t->pending.signal, SIGKILL);
2699 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2700 &sighand->action[SIGKILL - 1]);
2701 recalc_sigpending();
2705 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2709 if (unlikely(current->jobctl &
2710 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2711 if (current->jobctl & JOBCTL_TRAP_MASK) {
2713 spin_unlock_irq(&sighand->siglock);
2714 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2721 * If the task is leaving the frozen state, let's update
2722 * cgroup counters and reset the frozen bit.
2724 if (unlikely(cgroup_task_frozen(current))) {
2725 spin_unlock_irq(&sighand->siglock);
2726 cgroup_leave_frozen(false);
2731 * Signals generated by the execution of an instruction
2732 * need to be delivered before any other pending signals
2733 * so that the instruction pointer in the signal stack
2734 * frame points to the faulting instruction.
2737 signr = dequeue_synchronous_signal(&ksig->info);
2739 signr = dequeue_signal(current, ¤t->blocked,
2740 &ksig->info, &type);
2743 break; /* will return 0 */
2745 if (unlikely(current->ptrace) && (signr != SIGKILL) &&
2746 !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) {
2747 signr = ptrace_signal(signr, &ksig->info, type);
2752 ka = &sighand->action[signr-1];
2754 /* Trace actually delivered signals. */
2755 trace_signal_deliver(signr, &ksig->info, ka);
2757 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2759 if (ka->sa.sa_handler != SIG_DFL) {
2760 /* Run the handler. */
2763 if (ka->sa.sa_flags & SA_ONESHOT)
2764 ka->sa.sa_handler = SIG_DFL;
2766 break; /* will return non-zero "signr" value */
2770 * Now we are doing the default action for this signal.
2772 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2776 * Global init gets no signals it doesn't want.
2777 * Container-init gets no signals it doesn't want from same
2780 * Note that if global/container-init sees a sig_kernel_only()
2781 * signal here, the signal must have been generated internally
2782 * or must have come from an ancestor namespace. In either
2783 * case, the signal cannot be dropped.
2785 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2786 !sig_kernel_only(signr))
2789 if (sig_kernel_stop(signr)) {
2791 * The default action is to stop all threads in
2792 * the thread group. The job control signals
2793 * do nothing in an orphaned pgrp, but SIGSTOP
2794 * always works. Note that siglock needs to be
2795 * dropped during the call to is_orphaned_pgrp()
2796 * because of lock ordering with tasklist_lock.
2797 * This allows an intervening SIGCONT to be posted.
2798 * We need to check for that and bail out if necessary.
2800 if (signr != SIGSTOP) {
2801 spin_unlock_irq(&sighand->siglock);
2803 /* signals can be posted during this window */
2805 if (is_current_pgrp_orphaned())
2808 spin_lock_irq(&sighand->siglock);
2811 if (likely(do_signal_stop(ksig->info.si_signo))) {
2812 /* It released the siglock. */
2817 * We didn't actually stop, due to a race
2818 * with SIGCONT or something like that.
2824 spin_unlock_irq(&sighand->siglock);
2825 if (unlikely(cgroup_task_frozen(current)))
2826 cgroup_leave_frozen(true);
2829 * Anything else is fatal, maybe with a core dump.
2831 current->flags |= PF_SIGNALED;
2833 if (sig_kernel_coredump(signr)) {
2834 if (print_fatal_signals)
2835 print_fatal_signal(ksig->info.si_signo);
2836 proc_coredump_connector(current);
2838 * If it was able to dump core, this kills all
2839 * other threads in the group and synchronizes with
2840 * their demise. If we lost the race with another
2841 * thread getting here, it set group_exit_code
2842 * first and our do_group_exit call below will use
2843 * that value and ignore the one we pass it.
2845 do_coredump(&ksig->info);
2849 * PF_IO_WORKER threads will catch and exit on fatal signals
2850 * themselves. They have cleanup that must be performed, so
2851 * we cannot call do_exit() on their behalf.
2853 if (current->flags & PF_IO_WORKER)
2857 * Death signals, no core dump.
2859 do_group_exit(ksig->info.si_signo);
2862 spin_unlock_irq(&sighand->siglock);
2866 if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
2867 hide_si_addr_tag_bits(ksig);
2869 return ksig->sig > 0;
2873 * signal_delivered - called after signal delivery to update blocked signals
2874 * @ksig: kernel signal struct
2875 * @stepping: nonzero if debugger single-step or block-step in use
2877 * This function should be called when a signal has successfully been
2878 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2879 * is always blocked), and the signal itself is blocked unless %SA_NODEFER
2880 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2882 static void signal_delivered(struct ksignal *ksig, int stepping)
2886 /* A signal was successfully delivered, and the
2887 saved sigmask was stored on the signal frame,
2888 and will be restored by sigreturn. So we can
2889 simply clear the restore sigmask flag. */
2890 clear_restore_sigmask();
2892 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2893 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2894 sigaddset(&blocked, ksig->sig);
2895 set_current_blocked(&blocked);
2896 if (current->sas_ss_flags & SS_AUTODISARM)
2897 sas_ss_reset(current);
2899 ptrace_notify(SIGTRAP, 0);
2902 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2905 force_sigsegv(ksig->sig);
2907 signal_delivered(ksig, stepping);
2911 * It could be that complete_signal() picked us to notify about the
2912 * group-wide signal. Other threads should be notified now to take
2913 * the shared signals in @which since we will not.
2915 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2918 struct task_struct *t;
2920 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2921 if (sigisemptyset(&retarget))
2925 while_each_thread(tsk, t) {
2926 if (t->flags & PF_EXITING)
2929 if (!has_pending_signals(&retarget, &t->blocked))
2931 /* Remove the signals this thread can handle. */
2932 sigandsets(&retarget, &retarget, &t->blocked);
2934 if (!task_sigpending(t))
2935 signal_wake_up(t, 0);
2937 if (sigisemptyset(&retarget))
2942 void exit_signals(struct task_struct *tsk)
2948 * @tsk is about to have PF_EXITING set - lock out users which
2949 * expect stable threadgroup.
2951 cgroup_threadgroup_change_begin(tsk);
2953 if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
2954 tsk->flags |= PF_EXITING;
2955 cgroup_threadgroup_change_end(tsk);
2959 spin_lock_irq(&tsk->sighand->siglock);
2961 * From now this task is not visible for group-wide signals,
2962 * see wants_signal(), do_signal_stop().
2964 tsk->flags |= PF_EXITING;
2966 cgroup_threadgroup_change_end(tsk);
2968 if (!task_sigpending(tsk))
2971 unblocked = tsk->blocked;
2972 signotset(&unblocked);
2973 retarget_shared_pending(tsk, &unblocked);
2975 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2976 task_participate_group_stop(tsk))
2977 group_stop = CLD_STOPPED;
2979 spin_unlock_irq(&tsk->sighand->siglock);
2982 * If group stop has completed, deliver the notification. This
2983 * should always go to the real parent of the group leader.
2985 if (unlikely(group_stop)) {
2986 read_lock(&tasklist_lock);
2987 do_notify_parent_cldstop(tsk, false, group_stop);
2988 read_unlock(&tasklist_lock);
2993 * System call entry points.
2997 * sys_restart_syscall - restart a system call
2999 SYSCALL_DEFINE0(restart_syscall)
3001 struct restart_block *restart = ¤t->restart_block;
3002 return restart->fn(restart);
3005 long do_no_restart_syscall(struct restart_block *param)
3010 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
3012 if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
3013 sigset_t newblocked;
3014 /* A set of now blocked but previously unblocked signals. */
3015 sigandnsets(&newblocked, newset, ¤t->blocked);
3016 retarget_shared_pending(tsk, &newblocked);
3018 tsk->blocked = *newset;
3019 recalc_sigpending();
3023 * set_current_blocked - change current->blocked mask
3026 * It is wrong to change ->blocked directly, this helper should be used
3027 * to ensure the process can't miss a shared signal we are going to block.
3029 void set_current_blocked(sigset_t *newset)
3031 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
3032 __set_current_blocked(newset);
3035 void __set_current_blocked(const sigset_t *newset)
3037 struct task_struct *tsk = current;
3040 * In case the signal mask hasn't changed, there is nothing we need
3041 * to do. The current->blocked shouldn't be modified by other task.
3043 if (sigequalsets(&tsk->blocked, newset))
3046 spin_lock_irq(&tsk->sighand->siglock);
3047 __set_task_blocked(tsk, newset);
3048 spin_unlock_irq(&tsk->sighand->siglock);
3052 * This is also useful for kernel threads that want to temporarily
3053 * (or permanently) block certain signals.
3055 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
3056 * interface happily blocks "unblockable" signals like SIGKILL
3059 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
3061 struct task_struct *tsk = current;
3064 /* Lockless, only current can change ->blocked, never from irq */
3066 *oldset = tsk->blocked;
3070 sigorsets(&newset, &tsk->blocked, set);
3073 sigandnsets(&newset, &tsk->blocked, set);
3082 __set_current_blocked(&newset);
3085 EXPORT_SYMBOL(sigprocmask);
3088 * The api helps set app-provided sigmasks.
3090 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
3091 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
3093 * Note that it does set_restore_sigmask() in advance, so it must be always
3094 * paired with restore_saved_sigmask_unless() before return from syscall.
3096 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
3102 if (sigsetsize != sizeof(sigset_t))
3104 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
3107 set_restore_sigmask();
3108 current->saved_sigmask = current->blocked;
3109 set_current_blocked(&kmask);
3114 #ifdef CONFIG_COMPAT
3115 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3122 if (sigsetsize != sizeof(compat_sigset_t))
3124 if (get_compat_sigset(&kmask, umask))
3127 set_restore_sigmask();
3128 current->saved_sigmask = current->blocked;
3129 set_current_blocked(&kmask);
3136 * sys_rt_sigprocmask - change the list of currently blocked signals
3137 * @how: whether to add, remove, or set signals
3138 * @nset: stores pending signals
3139 * @oset: previous value of signal mask if non-null
3140 * @sigsetsize: size of sigset_t type
3142 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3143 sigset_t __user *, oset, size_t, sigsetsize)
3145 sigset_t old_set, new_set;
3148 /* XXX: Don't preclude handling different sized sigset_t's. */
3149 if (sigsetsize != sizeof(sigset_t))
3152 old_set = current->blocked;
3155 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3157 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3159 error = sigprocmask(how, &new_set, NULL);
3165 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3172 #ifdef CONFIG_COMPAT
3173 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3174 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3176 sigset_t old_set = current->blocked;
3178 /* XXX: Don't preclude handling different sized sigset_t's. */
3179 if (sigsetsize != sizeof(sigset_t))
3185 if (get_compat_sigset(&new_set, nset))
3187 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3189 error = sigprocmask(how, &new_set, NULL);
3193 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3197 static void do_sigpending(sigset_t *set)
3199 spin_lock_irq(¤t->sighand->siglock);
3200 sigorsets(set, ¤t->pending.signal,
3201 ¤t->signal->shared_pending.signal);
3202 spin_unlock_irq(¤t->sighand->siglock);
3204 /* Outside the lock because only this thread touches it. */
3205 sigandsets(set, ¤t->blocked, set);
3209 * sys_rt_sigpending - examine a pending signal that has been raised
3211 * @uset: stores pending signals
3212 * @sigsetsize: size of sigset_t type or larger
3214 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3218 if (sigsetsize > sizeof(*uset))
3221 do_sigpending(&set);
3223 if (copy_to_user(uset, &set, sigsetsize))
3229 #ifdef CONFIG_COMPAT
3230 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3231 compat_size_t, sigsetsize)
3235 if (sigsetsize > sizeof(*uset))
3238 do_sigpending(&set);
3240 return put_compat_sigset(uset, &set, sigsetsize);
3244 static const struct {
3245 unsigned char limit, layout;
3247 [SIGILL] = { NSIGILL, SIL_FAULT },
3248 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3249 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3250 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3251 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3253 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3255 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3256 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3257 [SIGSYS] = { NSIGSYS, SIL_SYS },
3260 static bool known_siginfo_layout(unsigned sig, int si_code)
3262 if (si_code == SI_KERNEL)
3264 else if ((si_code > SI_USER)) {
3265 if (sig_specific_sicodes(sig)) {
3266 if (si_code <= sig_sicodes[sig].limit)
3269 else if (si_code <= NSIGPOLL)
3272 else if (si_code >= SI_DETHREAD)
3274 else if (si_code == SI_ASYNCNL)
3279 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3281 enum siginfo_layout layout = SIL_KILL;
3282 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3283 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3284 (si_code <= sig_sicodes[sig].limit)) {
3285 layout = sig_sicodes[sig].layout;
3286 /* Handle the exceptions */
3287 if ((sig == SIGBUS) &&
3288 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3289 layout = SIL_FAULT_MCEERR;
3290 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3291 layout = SIL_FAULT_BNDERR;
3293 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3294 layout = SIL_FAULT_PKUERR;
3296 else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
3297 layout = SIL_FAULT_PERF_EVENT;
3298 else if (IS_ENABLED(CONFIG_SPARC) &&
3299 (sig == SIGILL) && (si_code == ILL_ILLTRP))
3300 layout = SIL_FAULT_TRAPNO;
3301 else if (IS_ENABLED(CONFIG_ALPHA) &&
3303 ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
3304 layout = SIL_FAULT_TRAPNO;
3306 else if (si_code <= NSIGPOLL)
3309 if (si_code == SI_TIMER)
3311 else if (si_code == SI_SIGIO)
3313 else if (si_code < 0)
3319 static inline char __user *si_expansion(const siginfo_t __user *info)
3321 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3324 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3326 char __user *expansion = si_expansion(to);
3327 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3329 if (clear_user(expansion, SI_EXPANSION_SIZE))
3334 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3335 const siginfo_t __user *from)
3337 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3338 char __user *expansion = si_expansion(from);
3339 char buf[SI_EXPANSION_SIZE];
3342 * An unknown si_code might need more than
3343 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3344 * extra bytes are 0. This guarantees copy_siginfo_to_user
3345 * will return this data to userspace exactly.
3347 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3349 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3357 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3358 const siginfo_t __user *from)
3360 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3362 to->si_signo = signo;
3363 return post_copy_siginfo_from_user(to, from);
3366 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3368 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3370 return post_copy_siginfo_from_user(to, from);
3373 #ifdef CONFIG_COMPAT
3375 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3376 * @to: compat siginfo destination
3377 * @from: kernel siginfo source
3379 * Note: This function does not work properly for the SIGCHLD on x32, but
3380 * fortunately it doesn't have to. The only valid callers for this function are
3381 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3382 * The latter does not care because SIGCHLD will never cause a coredump.
3384 void copy_siginfo_to_external32(struct compat_siginfo *to,
3385 const struct kernel_siginfo *from)
3387 memset(to, 0, sizeof(*to));
3389 to->si_signo = from->si_signo;
3390 to->si_errno = from->si_errno;
3391 to->si_code = from->si_code;
3392 switch(siginfo_layout(from->si_signo, from->si_code)) {
3394 to->si_pid = from->si_pid;
3395 to->si_uid = from->si_uid;
3398 to->si_tid = from->si_tid;
3399 to->si_overrun = from->si_overrun;
3400 to->si_int = from->si_int;
3403 to->si_band = from->si_band;
3404 to->si_fd = from->si_fd;
3407 to->si_addr = ptr_to_compat(from->si_addr);
3409 case SIL_FAULT_TRAPNO:
3410 to->si_addr = ptr_to_compat(from->si_addr);
3411 to->si_trapno = from->si_trapno;
3413 case SIL_FAULT_MCEERR:
3414 to->si_addr = ptr_to_compat(from->si_addr);
3415 to->si_addr_lsb = from->si_addr_lsb;
3417 case SIL_FAULT_BNDERR:
3418 to->si_addr = ptr_to_compat(from->si_addr);
3419 to->si_lower = ptr_to_compat(from->si_lower);
3420 to->si_upper = ptr_to_compat(from->si_upper);
3422 case SIL_FAULT_PKUERR:
3423 to->si_addr = ptr_to_compat(from->si_addr);
3424 to->si_pkey = from->si_pkey;
3426 case SIL_FAULT_PERF_EVENT:
3427 to->si_addr = ptr_to_compat(from->si_addr);
3428 to->si_perf_data = from->si_perf_data;
3429 to->si_perf_type = from->si_perf_type;
3430 to->si_perf_flags = from->si_perf_flags;
3433 to->si_pid = from->si_pid;
3434 to->si_uid = from->si_uid;
3435 to->si_status = from->si_status;
3436 to->si_utime = from->si_utime;
3437 to->si_stime = from->si_stime;
3440 to->si_pid = from->si_pid;
3441 to->si_uid = from->si_uid;
3442 to->si_int = from->si_int;
3445 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3446 to->si_syscall = from->si_syscall;
3447 to->si_arch = from->si_arch;
3452 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3453 const struct kernel_siginfo *from)
3455 struct compat_siginfo new;
3457 copy_siginfo_to_external32(&new, from);
3458 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3463 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3464 const struct compat_siginfo *from)
3467 to->si_signo = from->si_signo;
3468 to->si_errno = from->si_errno;
3469 to->si_code = from->si_code;
3470 switch(siginfo_layout(from->si_signo, from->si_code)) {
3472 to->si_pid = from->si_pid;
3473 to->si_uid = from->si_uid;
3476 to->si_tid = from->si_tid;
3477 to->si_overrun = from->si_overrun;
3478 to->si_int = from->si_int;
3481 to->si_band = from->si_band;
3482 to->si_fd = from->si_fd;
3485 to->si_addr = compat_ptr(from->si_addr);
3487 case SIL_FAULT_TRAPNO:
3488 to->si_addr = compat_ptr(from->si_addr);
3489 to->si_trapno = from->si_trapno;
3491 case SIL_FAULT_MCEERR:
3492 to->si_addr = compat_ptr(from->si_addr);
3493 to->si_addr_lsb = from->si_addr_lsb;
3495 case SIL_FAULT_BNDERR:
3496 to->si_addr = compat_ptr(from->si_addr);
3497 to->si_lower = compat_ptr(from->si_lower);
3498 to->si_upper = compat_ptr(from->si_upper);
3500 case SIL_FAULT_PKUERR:
3501 to->si_addr = compat_ptr(from->si_addr);
3502 to->si_pkey = from->si_pkey;
3504 case SIL_FAULT_PERF_EVENT:
3505 to->si_addr = compat_ptr(from->si_addr);
3506 to->si_perf_data = from->si_perf_data;
3507 to->si_perf_type = from->si_perf_type;
3508 to->si_perf_flags = from->si_perf_flags;
3511 to->si_pid = from->si_pid;
3512 to->si_uid = from->si_uid;
3513 to->si_status = from->si_status;
3514 #ifdef CONFIG_X86_X32_ABI
3515 if (in_x32_syscall()) {
3516 to->si_utime = from->_sifields._sigchld_x32._utime;
3517 to->si_stime = from->_sifields._sigchld_x32._stime;
3521 to->si_utime = from->si_utime;
3522 to->si_stime = from->si_stime;
3526 to->si_pid = from->si_pid;
3527 to->si_uid = from->si_uid;
3528 to->si_int = from->si_int;
3531 to->si_call_addr = compat_ptr(from->si_call_addr);
3532 to->si_syscall = from->si_syscall;
3533 to->si_arch = from->si_arch;
3539 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3540 const struct compat_siginfo __user *ufrom)
3542 struct compat_siginfo from;
3544 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3547 from.si_signo = signo;
3548 return post_copy_siginfo_from_user32(to, &from);
3551 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3552 const struct compat_siginfo __user *ufrom)
3554 struct compat_siginfo from;
3556 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3559 return post_copy_siginfo_from_user32(to, &from);
3561 #endif /* CONFIG_COMPAT */
3564 * do_sigtimedwait - wait for queued signals specified in @which
3565 * @which: queued signals to wait for
3566 * @info: if non-null, the signal's siginfo is returned here
3567 * @ts: upper bound on process time suspension
3569 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3570 const struct timespec64 *ts)
3572 ktime_t *to = NULL, timeout = KTIME_MAX;
3573 struct task_struct *tsk = current;
3574 sigset_t mask = *which;
3579 if (!timespec64_valid(ts))
3581 timeout = timespec64_to_ktime(*ts);
3586 * Invert the set of allowed signals to get those we want to block.
3588 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3591 spin_lock_irq(&tsk->sighand->siglock);
3592 sig = dequeue_signal(tsk, &mask, info, &type);
3593 if (!sig && timeout) {
3595 * None ready, temporarily unblock those we're interested
3596 * while we are sleeping in so that we'll be awakened when
3597 * they arrive. Unblocking is always fine, we can avoid
3598 * set_current_blocked().
3600 tsk->real_blocked = tsk->blocked;
3601 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3602 recalc_sigpending();
3603 spin_unlock_irq(&tsk->sighand->siglock);
3605 __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
3606 ret = schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3608 spin_lock_irq(&tsk->sighand->siglock);
3609 __set_task_blocked(tsk, &tsk->real_blocked);
3610 sigemptyset(&tsk->real_blocked);
3611 sig = dequeue_signal(tsk, &mask, info, &type);
3613 spin_unlock_irq(&tsk->sighand->siglock);
3617 return ret ? -EINTR : -EAGAIN;
3621 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3623 * @uthese: queued signals to wait for
3624 * @uinfo: if non-null, the signal's siginfo is returned here
3625 * @uts: upper bound on process time suspension
3626 * @sigsetsize: size of sigset_t type
3628 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3629 siginfo_t __user *, uinfo,
3630 const struct __kernel_timespec __user *, uts,
3634 struct timespec64 ts;
3635 kernel_siginfo_t info;
3638 /* XXX: Don't preclude handling different sized sigset_t's. */
3639 if (sigsetsize != sizeof(sigset_t))
3642 if (copy_from_user(&these, uthese, sizeof(these)))
3646 if (get_timespec64(&ts, uts))
3650 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3652 if (ret > 0 && uinfo) {
3653 if (copy_siginfo_to_user(uinfo, &info))
3660 #ifdef CONFIG_COMPAT_32BIT_TIME
3661 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3662 siginfo_t __user *, uinfo,
3663 const struct old_timespec32 __user *, uts,
3667 struct timespec64 ts;
3668 kernel_siginfo_t info;
3671 if (sigsetsize != sizeof(sigset_t))
3674 if (copy_from_user(&these, uthese, sizeof(these)))
3678 if (get_old_timespec32(&ts, uts))
3682 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3684 if (ret > 0 && uinfo) {
3685 if (copy_siginfo_to_user(uinfo, &info))
3693 #ifdef CONFIG_COMPAT
3694 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3695 struct compat_siginfo __user *, uinfo,
3696 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3699 struct timespec64 t;
3700 kernel_siginfo_t info;
3703 if (sigsetsize != sizeof(sigset_t))
3706 if (get_compat_sigset(&s, uthese))
3710 if (get_timespec64(&t, uts))
3714 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3716 if (ret > 0 && uinfo) {
3717 if (copy_siginfo_to_user32(uinfo, &info))
3724 #ifdef CONFIG_COMPAT_32BIT_TIME
3725 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3726 struct compat_siginfo __user *, uinfo,
3727 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3730 struct timespec64 t;
3731 kernel_siginfo_t info;
3734 if (sigsetsize != sizeof(sigset_t))
3737 if (get_compat_sigset(&s, uthese))
3741 if (get_old_timespec32(&t, uts))
3745 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3747 if (ret > 0 && uinfo) {
3748 if (copy_siginfo_to_user32(uinfo, &info))
3757 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3759 clear_siginfo(info);
3760 info->si_signo = sig;
3762 info->si_code = SI_USER;
3763 info->si_pid = task_tgid_vnr(current);
3764 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3768 * sys_kill - send a signal to a process
3769 * @pid: the PID of the process
3770 * @sig: signal to be sent
3772 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3774 struct kernel_siginfo info;
3776 prepare_kill_siginfo(sig, &info);
3778 return kill_something_info(sig, &info, pid);
3782 * Verify that the signaler and signalee either are in the same pid namespace
3783 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3786 static bool access_pidfd_pidns(struct pid *pid)
3788 struct pid_namespace *active = task_active_pid_ns(current);
3789 struct pid_namespace *p = ns_of_pid(pid);
3802 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
3803 siginfo_t __user *info)
3805 #ifdef CONFIG_COMPAT
3807 * Avoid hooking up compat syscalls and instead handle necessary
3808 * conversions here. Note, this is a stop-gap measure and should not be
3809 * considered a generic solution.
3811 if (in_compat_syscall())
3812 return copy_siginfo_from_user32(
3813 kinfo, (struct compat_siginfo __user *)info);
3815 return copy_siginfo_from_user(kinfo, info);
3818 static struct pid *pidfd_to_pid(const struct file *file)
3822 pid = pidfd_pid(file);
3826 return tgid_pidfd_to_pid(file);
3830 * sys_pidfd_send_signal - Signal a process through a pidfd
3831 * @pidfd: file descriptor of the process
3832 * @sig: signal to send
3833 * @info: signal info
3834 * @flags: future flags
3836 * The syscall currently only signals via PIDTYPE_PID which covers
3837 * kill(<positive-pid>, <signal>. It does not signal threads or process
3839 * In order to extend the syscall to threads and process groups the @flags
3840 * argument should be used. In essence, the @flags argument will determine
3841 * what is signaled and not the file descriptor itself. Put in other words,
3842 * grouping is a property of the flags argument not a property of the file
3845 * Return: 0 on success, negative errno on failure
3847 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3848 siginfo_t __user *, info, unsigned int, flags)
3853 kernel_siginfo_t kinfo;
3855 /* Enforce flags be set to 0 until we add an extension. */
3863 /* Is this a pidfd? */
3864 pid = pidfd_to_pid(f.file);
3871 if (!access_pidfd_pidns(pid))
3875 ret = copy_siginfo_from_user_any(&kinfo, info);
3880 if (unlikely(sig != kinfo.si_signo))
3883 /* Only allow sending arbitrary signals to yourself. */
3885 if ((task_pid(current) != pid) &&
3886 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3889 prepare_kill_siginfo(sig, &kinfo);
3892 ret = kill_pid_info(sig, &kinfo, pid);
3900 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3902 struct task_struct *p;
3906 p = find_task_by_vpid(pid);
3907 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3908 error = check_kill_permission(sig, info, p);
3910 * The null signal is a permissions and process existence
3911 * probe. No signal is actually delivered.
3913 if (!error && sig) {
3914 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3916 * If lock_task_sighand() failed we pretend the task
3917 * dies after receiving the signal. The window is tiny,
3918 * and the signal is private anyway.
3920 if (unlikely(error == -ESRCH))
3929 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3931 struct kernel_siginfo info;
3933 clear_siginfo(&info);
3934 info.si_signo = sig;
3936 info.si_code = SI_TKILL;
3937 info.si_pid = task_tgid_vnr(current);
3938 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3940 return do_send_specific(tgid, pid, sig, &info);
3944 * sys_tgkill - send signal to one specific thread
3945 * @tgid: the thread group ID of the thread
3946 * @pid: the PID of the thread
3947 * @sig: signal to be sent
3949 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3950 * exists but it's not belonging to the target process anymore. This
3951 * method solves the problem of threads exiting and PIDs getting reused.
3953 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3955 /* This is only valid for single tasks */
3956 if (pid <= 0 || tgid <= 0)
3959 return do_tkill(tgid, pid, sig);
3963 * sys_tkill - send signal to one specific task
3964 * @pid: the PID of the task
3965 * @sig: signal to be sent
3967 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3969 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3971 /* This is only valid for single tasks */
3975 return do_tkill(0, pid, sig);
3978 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3980 /* Not even root can pretend to send signals from the kernel.
3981 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3983 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3984 (task_pid_vnr(current) != pid))
3987 /* POSIX.1b doesn't mention process groups. */
3988 return kill_proc_info(sig, info, pid);
3992 * sys_rt_sigqueueinfo - send signal information to a signal
3993 * @pid: the PID of the thread
3994 * @sig: signal to be sent
3995 * @uinfo: signal info to be sent
3997 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3998 siginfo_t __user *, uinfo)
4000 kernel_siginfo_t info;
4001 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4004 return do_rt_sigqueueinfo(pid, sig, &info);
4007 #ifdef CONFIG_COMPAT
4008 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
4011 struct compat_siginfo __user *, uinfo)
4013 kernel_siginfo_t info;
4014 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4017 return do_rt_sigqueueinfo(pid, sig, &info);
4021 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
4023 /* This is only valid for single tasks */
4024 if (pid <= 0 || tgid <= 0)
4027 /* Not even root can pretend to send signals from the kernel.
4028 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4030 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4031 (task_pid_vnr(current) != pid))
4034 return do_send_specific(tgid, pid, sig, info);
4037 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
4038 siginfo_t __user *, uinfo)
4040 kernel_siginfo_t info;
4041 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4044 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4047 #ifdef CONFIG_COMPAT
4048 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
4052 struct compat_siginfo __user *, uinfo)
4054 kernel_siginfo_t info;
4055 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4058 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4063 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
4065 void kernel_sigaction(int sig, __sighandler_t action)
4067 spin_lock_irq(¤t->sighand->siglock);
4068 current->sighand->action[sig - 1].sa.sa_handler = action;
4069 if (action == SIG_IGN) {
4073 sigaddset(&mask, sig);
4075 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
4076 flush_sigqueue_mask(&mask, ¤t->pending);
4077 recalc_sigpending();
4079 spin_unlock_irq(¤t->sighand->siglock);
4081 EXPORT_SYMBOL(kernel_sigaction);
4083 void __weak sigaction_compat_abi(struct k_sigaction *act,
4084 struct k_sigaction *oact)
4088 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
4090 struct task_struct *p = current, *t;
4091 struct k_sigaction *k;
4094 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
4097 k = &p->sighand->action[sig-1];
4099 spin_lock_irq(&p->sighand->siglock);
4100 if (k->sa.sa_flags & SA_IMMUTABLE) {
4101 spin_unlock_irq(&p->sighand->siglock);
4108 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
4109 * e.g. by having an architecture use the bit in their uapi.
4111 BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
4114 * Clear unknown flag bits in order to allow userspace to detect missing
4115 * support for flag bits and to allow the kernel to use non-uapi bits
4119 act->sa.sa_flags &= UAPI_SA_FLAGS;
4121 oact->sa.sa_flags &= UAPI_SA_FLAGS;
4123 sigaction_compat_abi(act, oact);
4126 sigdelsetmask(&act->sa.sa_mask,
4127 sigmask(SIGKILL) | sigmask(SIGSTOP));
4131 * "Setting a signal action to SIG_IGN for a signal that is
4132 * pending shall cause the pending signal to be discarded,
4133 * whether or not it is blocked."
4135 * "Setting a signal action to SIG_DFL for a signal that is
4136 * pending and whose default action is to ignore the signal
4137 * (for example, SIGCHLD), shall cause the pending signal to
4138 * be discarded, whether or not it is blocked"
4140 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
4142 sigaddset(&mask, sig);
4143 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
4144 for_each_thread(p, t)
4145 flush_sigqueue_mask(&mask, &t->pending);
4149 spin_unlock_irq(&p->sighand->siglock);
4153 #ifdef CONFIG_DYNAMIC_SIGFRAME
4154 static inline void sigaltstack_lock(void)
4155 __acquires(¤t->sighand->siglock)
4157 spin_lock_irq(¤t->sighand->siglock);
4160 static inline void sigaltstack_unlock(void)
4161 __releases(¤t->sighand->siglock)
4163 spin_unlock_irq(¤t->sighand->siglock);
4166 static inline void sigaltstack_lock(void) { }
4167 static inline void sigaltstack_unlock(void) { }
4171 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4174 struct task_struct *t = current;
4178 memset(oss, 0, sizeof(stack_t));
4179 oss->ss_sp = (void __user *) t->sas_ss_sp;
4180 oss->ss_size = t->sas_ss_size;
4181 oss->ss_flags = sas_ss_flags(sp) |
4182 (current->sas_ss_flags & SS_FLAG_BITS);
4186 void __user *ss_sp = ss->ss_sp;
4187 size_t ss_size = ss->ss_size;
4188 unsigned ss_flags = ss->ss_flags;
4191 if (unlikely(on_sig_stack(sp)))
4194 ss_mode = ss_flags & ~SS_FLAG_BITS;
4195 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4200 * Return before taking any locks if no actual
4201 * sigaltstack changes were requested.
4203 if (t->sas_ss_sp == (unsigned long)ss_sp &&
4204 t->sas_ss_size == ss_size &&
4205 t->sas_ss_flags == ss_flags)
4209 if (ss_mode == SS_DISABLE) {
4213 if (unlikely(ss_size < min_ss_size))
4215 if (!sigaltstack_size_valid(ss_size))
4219 t->sas_ss_sp = (unsigned long) ss_sp;
4220 t->sas_ss_size = ss_size;
4221 t->sas_ss_flags = ss_flags;
4223 sigaltstack_unlock();
4228 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4232 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4234 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4235 current_user_stack_pointer(),
4237 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4242 int restore_altstack(const stack_t __user *uss)
4245 if (copy_from_user(&new, uss, sizeof(stack_t)))
4247 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4249 /* squash all but EFAULT for now */
4253 int __save_altstack(stack_t __user *uss, unsigned long sp)
4255 struct task_struct *t = current;
4256 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4257 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4258 __put_user(t->sas_ss_size, &uss->ss_size);
4262 #ifdef CONFIG_COMPAT
4263 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4264 compat_stack_t __user *uoss_ptr)
4270 compat_stack_t uss32;
4271 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4273 uss.ss_sp = compat_ptr(uss32.ss_sp);
4274 uss.ss_flags = uss32.ss_flags;
4275 uss.ss_size = uss32.ss_size;
4277 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4278 compat_user_stack_pointer(),
4279 COMPAT_MINSIGSTKSZ);
4280 if (ret >= 0 && uoss_ptr) {
4282 memset(&old, 0, sizeof(old));
4283 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4284 old.ss_flags = uoss.ss_flags;
4285 old.ss_size = uoss.ss_size;
4286 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4292 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4293 const compat_stack_t __user *, uss_ptr,
4294 compat_stack_t __user *, uoss_ptr)
4296 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4299 int compat_restore_altstack(const compat_stack_t __user *uss)
4301 int err = do_compat_sigaltstack(uss, NULL);
4302 /* squash all but -EFAULT for now */
4303 return err == -EFAULT ? err : 0;
4306 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4309 struct task_struct *t = current;
4310 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4312 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4313 __put_user(t->sas_ss_size, &uss->ss_size);
4318 #ifdef __ARCH_WANT_SYS_SIGPENDING
4321 * sys_sigpending - examine pending signals
4322 * @uset: where mask of pending signal is returned
4324 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4328 if (sizeof(old_sigset_t) > sizeof(*uset))
4331 do_sigpending(&set);
4333 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4339 #ifdef CONFIG_COMPAT
4340 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4344 do_sigpending(&set);
4346 return put_user(set.sig[0], set32);
4352 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4354 * sys_sigprocmask - examine and change blocked signals
4355 * @how: whether to add, remove, or set signals
4356 * @nset: signals to add or remove (if non-null)
4357 * @oset: previous value of signal mask if non-null
4359 * Some platforms have their own version with special arguments;
4360 * others support only sys_rt_sigprocmask.
4363 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4364 old_sigset_t __user *, oset)
4366 old_sigset_t old_set, new_set;
4367 sigset_t new_blocked;
4369 old_set = current->blocked.sig[0];
4372 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4375 new_blocked = current->blocked;
4379 sigaddsetmask(&new_blocked, new_set);
4382 sigdelsetmask(&new_blocked, new_set);
4385 new_blocked.sig[0] = new_set;
4391 set_current_blocked(&new_blocked);
4395 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4401 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4403 #ifndef CONFIG_ODD_RT_SIGACTION
4405 * sys_rt_sigaction - alter an action taken by a process
4406 * @sig: signal to be sent
4407 * @act: new sigaction
4408 * @oact: used to save the previous sigaction
4409 * @sigsetsize: size of sigset_t type
4411 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4412 const struct sigaction __user *, act,
4413 struct sigaction __user *, oact,
4416 struct k_sigaction new_sa, old_sa;
4419 /* XXX: Don't preclude handling different sized sigset_t's. */
4420 if (sigsetsize != sizeof(sigset_t))
4423 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4426 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4430 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4435 #ifdef CONFIG_COMPAT
4436 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4437 const struct compat_sigaction __user *, act,
4438 struct compat_sigaction __user *, oact,
4439 compat_size_t, sigsetsize)
4441 struct k_sigaction new_ka, old_ka;
4442 #ifdef __ARCH_HAS_SA_RESTORER
4443 compat_uptr_t restorer;
4447 /* XXX: Don't preclude handling different sized sigset_t's. */
4448 if (sigsetsize != sizeof(compat_sigset_t))
4452 compat_uptr_t handler;
4453 ret = get_user(handler, &act->sa_handler);
4454 new_ka.sa.sa_handler = compat_ptr(handler);
4455 #ifdef __ARCH_HAS_SA_RESTORER
4456 ret |= get_user(restorer, &act->sa_restorer);
4457 new_ka.sa.sa_restorer = compat_ptr(restorer);
4459 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4460 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4465 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4467 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4469 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4470 sizeof(oact->sa_mask));
4471 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4472 #ifdef __ARCH_HAS_SA_RESTORER
4473 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4474 &oact->sa_restorer);
4480 #endif /* !CONFIG_ODD_RT_SIGACTION */
4482 #ifdef CONFIG_OLD_SIGACTION
4483 SYSCALL_DEFINE3(sigaction, int, sig,
4484 const struct old_sigaction __user *, act,
4485 struct old_sigaction __user *, oact)
4487 struct k_sigaction new_ka, old_ka;
4492 if (!access_ok(act, sizeof(*act)) ||
4493 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4494 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4495 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4496 __get_user(mask, &act->sa_mask))
4498 #ifdef __ARCH_HAS_KA_RESTORER
4499 new_ka.ka_restorer = NULL;
4501 siginitset(&new_ka.sa.sa_mask, mask);
4504 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4507 if (!access_ok(oact, sizeof(*oact)) ||
4508 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4509 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4510 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4511 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4518 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4519 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4520 const struct compat_old_sigaction __user *, act,
4521 struct compat_old_sigaction __user *, oact)
4523 struct k_sigaction new_ka, old_ka;
4525 compat_old_sigset_t mask;
4526 compat_uptr_t handler, restorer;
4529 if (!access_ok(act, sizeof(*act)) ||
4530 __get_user(handler, &act->sa_handler) ||
4531 __get_user(restorer, &act->sa_restorer) ||
4532 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4533 __get_user(mask, &act->sa_mask))
4536 #ifdef __ARCH_HAS_KA_RESTORER
4537 new_ka.ka_restorer = NULL;
4539 new_ka.sa.sa_handler = compat_ptr(handler);
4540 new_ka.sa.sa_restorer = compat_ptr(restorer);
4541 siginitset(&new_ka.sa.sa_mask, mask);
4544 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4547 if (!access_ok(oact, sizeof(*oact)) ||
4548 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4549 &oact->sa_handler) ||
4550 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4551 &oact->sa_restorer) ||
4552 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4553 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4560 #ifdef CONFIG_SGETMASK_SYSCALL
4563 * For backwards compatibility. Functionality superseded by sigprocmask.
4565 SYSCALL_DEFINE0(sgetmask)
4568 return current->blocked.sig[0];
4571 SYSCALL_DEFINE1(ssetmask, int, newmask)
4573 int old = current->blocked.sig[0];
4576 siginitset(&newset, newmask);
4577 set_current_blocked(&newset);
4581 #endif /* CONFIG_SGETMASK_SYSCALL */
4583 #ifdef __ARCH_WANT_SYS_SIGNAL
4585 * For backwards compatibility. Functionality superseded by sigaction.
4587 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4589 struct k_sigaction new_sa, old_sa;
4592 new_sa.sa.sa_handler = handler;
4593 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4594 sigemptyset(&new_sa.sa.sa_mask);
4596 ret = do_sigaction(sig, &new_sa, &old_sa);
4598 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4600 #endif /* __ARCH_WANT_SYS_SIGNAL */
4602 #ifdef __ARCH_WANT_SYS_PAUSE
4604 SYSCALL_DEFINE0(pause)
4606 while (!signal_pending(current)) {
4607 __set_current_state(TASK_INTERRUPTIBLE);
4610 return -ERESTARTNOHAND;
4615 static int sigsuspend(sigset_t *set)
4617 current->saved_sigmask = current->blocked;
4618 set_current_blocked(set);
4620 while (!signal_pending(current)) {
4621 __set_current_state(TASK_INTERRUPTIBLE);
4624 set_restore_sigmask();
4625 return -ERESTARTNOHAND;
4629 * sys_rt_sigsuspend - replace the signal mask for a value with the
4630 * @unewset value until a signal is received
4631 * @unewset: new signal mask value
4632 * @sigsetsize: size of sigset_t type
4634 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4638 /* XXX: Don't preclude handling different sized sigset_t's. */
4639 if (sigsetsize != sizeof(sigset_t))
4642 if (copy_from_user(&newset, unewset, sizeof(newset)))
4644 return sigsuspend(&newset);
4647 #ifdef CONFIG_COMPAT
4648 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4652 /* XXX: Don't preclude handling different sized sigset_t's. */
4653 if (sigsetsize != sizeof(sigset_t))
4656 if (get_compat_sigset(&newset, unewset))
4658 return sigsuspend(&newset);
4662 #ifdef CONFIG_OLD_SIGSUSPEND
4663 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4666 siginitset(&blocked, mask);
4667 return sigsuspend(&blocked);
4670 #ifdef CONFIG_OLD_SIGSUSPEND3
4671 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4674 siginitset(&blocked, mask);
4675 return sigsuspend(&blocked);
4679 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4684 static inline void siginfo_buildtime_checks(void)
4686 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4688 /* Verify the offsets in the two siginfos match */
4689 #define CHECK_OFFSET(field) \
4690 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4693 CHECK_OFFSET(si_pid);
4694 CHECK_OFFSET(si_uid);
4697 CHECK_OFFSET(si_tid);
4698 CHECK_OFFSET(si_overrun);
4699 CHECK_OFFSET(si_value);
4702 CHECK_OFFSET(si_pid);
4703 CHECK_OFFSET(si_uid);
4704 CHECK_OFFSET(si_value);
4707 CHECK_OFFSET(si_pid);
4708 CHECK_OFFSET(si_uid);
4709 CHECK_OFFSET(si_status);
4710 CHECK_OFFSET(si_utime);
4711 CHECK_OFFSET(si_stime);
4714 CHECK_OFFSET(si_addr);
4715 CHECK_OFFSET(si_trapno);
4716 CHECK_OFFSET(si_addr_lsb);
4717 CHECK_OFFSET(si_lower);
4718 CHECK_OFFSET(si_upper);
4719 CHECK_OFFSET(si_pkey);
4720 CHECK_OFFSET(si_perf_data);
4721 CHECK_OFFSET(si_perf_type);
4722 CHECK_OFFSET(si_perf_flags);
4725 CHECK_OFFSET(si_band);
4726 CHECK_OFFSET(si_fd);
4729 CHECK_OFFSET(si_call_addr);
4730 CHECK_OFFSET(si_syscall);
4731 CHECK_OFFSET(si_arch);
4735 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4736 offsetof(struct siginfo, si_addr));
4737 if (sizeof(int) == sizeof(void __user *)) {
4738 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4739 sizeof(void __user *));
4741 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4742 sizeof_field(struct siginfo, si_uid)) !=
4743 sizeof(void __user *));
4744 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4745 offsetof(struct siginfo, si_uid));
4747 #ifdef CONFIG_COMPAT
4748 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4749 offsetof(struct compat_siginfo, si_addr));
4750 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4751 sizeof(compat_uptr_t));
4752 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4753 sizeof_field(struct siginfo, si_pid));
4757 void __init signals_init(void)
4759 siginfo_buildtime_checks();
4761 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT);
4764 #ifdef CONFIG_KGDB_KDB
4765 #include <linux/kdb.h>
4767 * kdb_send_sig - Allows kdb to send signals without exposing
4768 * signal internals. This function checks if the required locks are
4769 * available before calling the main signal code, to avoid kdb
4772 void kdb_send_sig(struct task_struct *t, int sig)
4774 static struct task_struct *kdb_prev_t;
4776 if (!spin_trylock(&t->sighand->siglock)) {
4777 kdb_printf("Can't do kill command now.\n"
4778 "The sigmask lock is held somewhere else in "
4779 "kernel, try again later\n");
4782 new_t = kdb_prev_t != t;
4784 if (!task_is_running(t) && new_t) {
4785 spin_unlock(&t->sighand->siglock);
4786 kdb_printf("Process is not RUNNING, sending a signal from "
4787 "kdb risks deadlock\n"
4788 "on the run queue locks. "
4789 "The signal has _not_ been sent.\n"
4790 "Reissue the kill command if you want to risk "
4794 ret = send_signal_locked(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4795 spin_unlock(&t->sighand->siglock);
4797 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4800 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4802 #endif /* CONFIG_KGDB_KDB */