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 set_tsk_thread_flag(t, TIF_SIGPENDING);
767 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
768 * case. We don't check t->state here because there is a race with it
769 * executing another processor and just now entering stopped state.
770 * By using wake_up_state, we ensure the process will wake up and
771 * handle its death signal.
773 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
778 * Remove signals in mask from the pending set and queue.
779 * Returns 1 if any signals were found.
781 * All callers must be holding the siglock.
783 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
785 struct sigqueue *q, *n;
788 sigandsets(&m, mask, &s->signal);
789 if (sigisemptyset(&m))
792 sigandnsets(&s->signal, &s->signal, mask);
793 list_for_each_entry_safe(q, n, &s->list, list) {
794 if (sigismember(mask, q->info.si_signo)) {
795 list_del_init(&q->list);
801 static inline int is_si_special(const struct kernel_siginfo *info)
803 return info <= SEND_SIG_PRIV;
806 static inline bool si_fromuser(const struct kernel_siginfo *info)
808 return info == SEND_SIG_NOINFO ||
809 (!is_si_special(info) && SI_FROMUSER(info));
813 * called with RCU read lock from check_kill_permission()
815 static bool kill_ok_by_cred(struct task_struct *t)
817 const struct cred *cred = current_cred();
818 const struct cred *tcred = __task_cred(t);
820 return uid_eq(cred->euid, tcred->suid) ||
821 uid_eq(cred->euid, tcred->uid) ||
822 uid_eq(cred->uid, tcred->suid) ||
823 uid_eq(cred->uid, tcred->uid) ||
824 ns_capable(tcred->user_ns, CAP_KILL);
828 * Bad permissions for sending the signal
829 * - the caller must hold the RCU read lock
831 static int check_kill_permission(int sig, struct kernel_siginfo *info,
832 struct task_struct *t)
837 if (!valid_signal(sig))
840 if (!si_fromuser(info))
843 error = audit_signal_info(sig, t); /* Let audit system see the signal */
847 if (!same_thread_group(current, t) &&
848 !kill_ok_by_cred(t)) {
851 sid = task_session(t);
853 * We don't return the error if sid == NULL. The
854 * task was unhashed, the caller must notice this.
856 if (!sid || sid == task_session(current))
864 return security_task_kill(t, info, sig, NULL);
868 * ptrace_trap_notify - schedule trap to notify ptracer
869 * @t: tracee wanting to notify tracer
871 * This function schedules sticky ptrace trap which is cleared on the next
872 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
875 * If @t is running, STOP trap will be taken. If trapped for STOP and
876 * ptracer is listening for events, tracee is woken up so that it can
877 * re-trap for the new event. If trapped otherwise, STOP trap will be
878 * eventually taken without returning to userland after the existing traps
879 * are finished by PTRACE_CONT.
882 * Must be called with @task->sighand->siglock held.
884 static void ptrace_trap_notify(struct task_struct *t)
886 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
887 assert_spin_locked(&t->sighand->siglock);
889 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
890 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
894 * Handle magic process-wide effects of stop/continue signals. Unlike
895 * the signal actions, these happen immediately at signal-generation
896 * time regardless of blocking, ignoring, or handling. This does the
897 * actual continuing for SIGCONT, but not the actual stopping for stop
898 * signals. The process stop is done as a signal action for SIG_DFL.
900 * Returns true if the signal should be actually delivered, otherwise
901 * it should be dropped.
903 static bool prepare_signal(int sig, struct task_struct *p, bool force)
905 struct signal_struct *signal = p->signal;
906 struct task_struct *t;
909 if (signal->flags & SIGNAL_GROUP_EXIT) {
910 if (signal->core_state)
911 return sig == SIGKILL;
913 * The process is in the middle of dying, nothing to do.
915 } else if (sig_kernel_stop(sig)) {
917 * This is a stop signal. Remove SIGCONT from all queues.
919 siginitset(&flush, sigmask(SIGCONT));
920 flush_sigqueue_mask(&flush, &signal->shared_pending);
921 for_each_thread(p, t)
922 flush_sigqueue_mask(&flush, &t->pending);
923 } else if (sig == SIGCONT) {
926 * Remove all stop signals from all queues, wake all threads.
928 siginitset(&flush, SIG_KERNEL_STOP_MASK);
929 flush_sigqueue_mask(&flush, &signal->shared_pending);
930 for_each_thread(p, t) {
931 flush_sigqueue_mask(&flush, &t->pending);
932 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
933 if (likely(!(t->ptrace & PT_SEIZED)))
934 wake_up_state(t, __TASK_STOPPED);
936 ptrace_trap_notify(t);
940 * Notify the parent with CLD_CONTINUED if we were stopped.
942 * If we were in the middle of a group stop, we pretend it
943 * was already finished, and then continued. Since SIGCHLD
944 * doesn't queue we report only CLD_STOPPED, as if the next
945 * CLD_CONTINUED was dropped.
948 if (signal->flags & SIGNAL_STOP_STOPPED)
949 why |= SIGNAL_CLD_CONTINUED;
950 else if (signal->group_stop_count)
951 why |= SIGNAL_CLD_STOPPED;
955 * The first thread which returns from do_signal_stop()
956 * will take ->siglock, notice SIGNAL_CLD_MASK, and
957 * notify its parent. See get_signal().
959 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
960 signal->group_stop_count = 0;
961 signal->group_exit_code = 0;
965 return !sig_ignored(p, sig, force);
969 * Test if P wants to take SIG. After we've checked all threads with this,
970 * it's equivalent to finding no threads not blocking SIG. Any threads not
971 * blocking SIG were ruled out because they are not running and already
972 * have pending signals. Such threads will dequeue from the shared queue
973 * as soon as they're available, so putting the signal on the shared queue
974 * will be equivalent to sending it to one such thread.
976 static inline bool wants_signal(int sig, struct task_struct *p)
978 if (sigismember(&p->blocked, sig))
981 if (p->flags & PF_EXITING)
987 if (task_is_stopped_or_traced(p))
990 return task_curr(p) || !task_sigpending(p);
993 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
995 struct signal_struct *signal = p->signal;
996 struct task_struct *t;
999 * Now find a thread we can wake up to take the signal off the queue.
1001 * If the main thread wants the signal, it gets first crack.
1002 * Probably the least surprising to the average bear.
1004 if (wants_signal(sig, p))
1006 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1008 * There is just one thread and it does not need to be woken.
1009 * It will dequeue unblocked signals before it runs again.
1014 * Otherwise try to find a suitable thread.
1016 t = signal->curr_target;
1017 while (!wants_signal(sig, t)) {
1019 if (t == signal->curr_target)
1021 * No thread needs to be woken.
1022 * Any eligible threads will see
1023 * the signal in the queue soon.
1027 signal->curr_target = t;
1031 * Found a killable thread. If the signal will be fatal,
1032 * then start taking the whole group down immediately.
1034 if (sig_fatal(p, sig) &&
1035 (signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) &&
1036 !sigismember(&t->real_blocked, sig) &&
1037 (sig == SIGKILL || !p->ptrace)) {
1039 * This signal will be fatal to the whole group.
1041 if (!sig_kernel_coredump(sig)) {
1043 * Start a group exit and wake everybody up.
1044 * This way we don't have other threads
1045 * running and doing things after a slower
1046 * thread has the fatal signal pending.
1048 signal->flags = SIGNAL_GROUP_EXIT;
1049 signal->group_exit_code = sig;
1050 signal->group_stop_count = 0;
1053 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1054 sigaddset(&t->pending.signal, SIGKILL);
1055 signal_wake_up(t, 1);
1056 } while_each_thread(p, t);
1062 * The signal is already in the shared-pending queue.
1063 * Tell the chosen thread to wake up and dequeue it.
1065 signal_wake_up(t, sig == SIGKILL);
1069 static inline bool legacy_queue(struct sigpending *signals, int sig)
1071 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1074 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1075 enum pid_type type, bool force)
1077 struct sigpending *pending;
1079 int override_rlimit;
1080 int ret = 0, result;
1082 assert_spin_locked(&t->sighand->siglock);
1084 result = TRACE_SIGNAL_IGNORED;
1085 if (!prepare_signal(sig, t, force))
1088 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1090 * Short-circuit ignored signals and support queuing
1091 * exactly one non-rt signal, so that we can get more
1092 * detailed information about the cause of the signal.
1094 result = TRACE_SIGNAL_ALREADY_PENDING;
1095 if (legacy_queue(pending, sig))
1098 result = TRACE_SIGNAL_DELIVERED;
1100 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1102 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1106 * Real-time signals must be queued if sent by sigqueue, or
1107 * some other real-time mechanism. It is implementation
1108 * defined whether kill() does so. We attempt to do so, on
1109 * the principle of least surprise, but since kill is not
1110 * allowed to fail with EAGAIN when low on memory we just
1111 * make sure at least one signal gets delivered and don't
1112 * pass on the info struct.
1115 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1117 override_rlimit = 0;
1119 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
1122 list_add_tail(&q->list, &pending->list);
1123 switch ((unsigned long) info) {
1124 case (unsigned long) SEND_SIG_NOINFO:
1125 clear_siginfo(&q->info);
1126 q->info.si_signo = sig;
1127 q->info.si_errno = 0;
1128 q->info.si_code = SI_USER;
1129 q->info.si_pid = task_tgid_nr_ns(current,
1130 task_active_pid_ns(t));
1133 from_kuid_munged(task_cred_xxx(t, user_ns),
1137 case (unsigned long) SEND_SIG_PRIV:
1138 clear_siginfo(&q->info);
1139 q->info.si_signo = sig;
1140 q->info.si_errno = 0;
1141 q->info.si_code = SI_KERNEL;
1146 copy_siginfo(&q->info, info);
1149 } else if (!is_si_special(info) &&
1150 sig >= SIGRTMIN && info->si_code != SI_USER) {
1152 * Queue overflow, abort. We may abort if the
1153 * signal was rt and sent by user using something
1154 * other than kill().
1156 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1161 * This is a silent loss of information. We still
1162 * send the signal, but the *info bits are lost.
1164 result = TRACE_SIGNAL_LOSE_INFO;
1168 signalfd_notify(t, sig);
1169 sigaddset(&pending->signal, sig);
1171 /* Let multiprocess signals appear after on-going forks */
1172 if (type > PIDTYPE_TGID) {
1173 struct multiprocess_signals *delayed;
1174 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1175 sigset_t *signal = &delayed->signal;
1176 /* Can't queue both a stop and a continue signal */
1178 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1179 else if (sig_kernel_stop(sig))
1180 sigdelset(signal, SIGCONT);
1181 sigaddset(signal, sig);
1185 complete_signal(sig, t, type);
1187 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1191 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1194 switch (siginfo_layout(info->si_signo, info->si_code)) {
1203 case SIL_FAULT_TRAPNO:
1204 case SIL_FAULT_MCEERR:
1205 case SIL_FAULT_BNDERR:
1206 case SIL_FAULT_PKUERR:
1207 case SIL_FAULT_PERF_EVENT:
1215 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1218 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1221 if (info == SEND_SIG_NOINFO) {
1222 /* Force if sent from an ancestor pid namespace */
1223 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1224 } else if (info == SEND_SIG_PRIV) {
1225 /* Don't ignore kernel generated signals */
1227 } else if (has_si_pid_and_uid(info)) {
1228 /* SIGKILL and SIGSTOP is special or has ids */
1229 struct user_namespace *t_user_ns;
1232 t_user_ns = task_cred_xxx(t, user_ns);
1233 if (current_user_ns() != t_user_ns) {
1234 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1235 info->si_uid = from_kuid_munged(t_user_ns, uid);
1239 /* A kernel generated signal? */
1240 force = (info->si_code == SI_KERNEL);
1242 /* From an ancestor pid namespace? */
1243 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1248 return __send_signal(sig, info, t, type, force);
1251 static void print_fatal_signal(int signr)
1253 struct pt_regs *regs = signal_pt_regs();
1254 pr_info("potentially unexpected fatal signal %d.\n", signr);
1256 #if defined(__i386__) && !defined(__arch_um__)
1257 pr_info("code at %08lx: ", regs->ip);
1260 for (i = 0; i < 16; i++) {
1263 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1265 pr_cont("%02x ", insn);
1275 static int __init setup_print_fatal_signals(char *str)
1277 get_option (&str, &print_fatal_signals);
1282 __setup("print-fatal-signals=", setup_print_fatal_signals);
1285 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1287 return send_signal(sig, info, p, PIDTYPE_TGID);
1290 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1293 unsigned long flags;
1296 if (lock_task_sighand(p, &flags)) {
1297 ret = send_signal(sig, info, p, type);
1298 unlock_task_sighand(p, &flags);
1305 HANDLER_CURRENT, /* If reachable use the current handler */
1306 HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */
1307 HANDLER_EXIT, /* Only visible as the process exit code */
1311 * Force a signal that the process can't ignore: if necessary
1312 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1314 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1315 * since we do not want to have a signal handler that was blocked
1316 * be invoked when user space had explicitly blocked it.
1318 * We don't want to have recursive SIGSEGV's etc, for example,
1319 * that is why we also clear SIGNAL_UNKILLABLE.
1322 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
1323 enum sig_handler handler)
1325 unsigned long int flags;
1326 int ret, blocked, ignored;
1327 struct k_sigaction *action;
1328 int sig = info->si_signo;
1330 spin_lock_irqsave(&t->sighand->siglock, flags);
1331 action = &t->sighand->action[sig-1];
1332 ignored = action->sa.sa_handler == SIG_IGN;
1333 blocked = sigismember(&t->blocked, sig);
1334 if (blocked || ignored || (handler != HANDLER_CURRENT)) {
1335 action->sa.sa_handler = SIG_DFL;
1336 if (handler == HANDLER_EXIT)
1337 action->sa.sa_flags |= SA_IMMUTABLE;
1339 sigdelset(&t->blocked, sig);
1340 recalc_sigpending_and_wake(t);
1344 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1345 * debugging to leave init killable. But HANDLER_EXIT is always fatal.
1347 if (action->sa.sa_handler == SIG_DFL &&
1348 (!t->ptrace || (handler == HANDLER_EXIT)))
1349 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1350 ret = send_signal(sig, info, t, PIDTYPE_PID);
1351 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1356 int force_sig_info(struct kernel_siginfo *info)
1358 return force_sig_info_to_task(info, current, HANDLER_CURRENT);
1362 * Nuke all other threads in the group.
1364 int zap_other_threads(struct task_struct *p)
1366 struct task_struct *t = p;
1369 p->signal->group_stop_count = 0;
1371 while_each_thread(p, t) {
1372 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1375 /* Don't bother with already dead threads */
1378 sigaddset(&t->pending.signal, SIGKILL);
1379 signal_wake_up(t, 1);
1385 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1386 unsigned long *flags)
1388 struct sighand_struct *sighand;
1392 sighand = rcu_dereference(tsk->sighand);
1393 if (unlikely(sighand == NULL))
1397 * This sighand can be already freed and even reused, but
1398 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1399 * initializes ->siglock: this slab can't go away, it has
1400 * the same object type, ->siglock can't be reinitialized.
1402 * We need to ensure that tsk->sighand is still the same
1403 * after we take the lock, we can race with de_thread() or
1404 * __exit_signal(). In the latter case the next iteration
1405 * must see ->sighand == NULL.
1407 spin_lock_irqsave(&sighand->siglock, *flags);
1408 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1410 spin_unlock_irqrestore(&sighand->siglock, *flags);
1417 #ifdef CONFIG_LOCKDEP
1418 void lockdep_assert_task_sighand_held(struct task_struct *task)
1420 struct sighand_struct *sighand;
1423 sighand = rcu_dereference(task->sighand);
1425 lockdep_assert_held(&sighand->siglock);
1433 * send signal info to all the members of a group
1435 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1436 struct task_struct *p, enum pid_type type)
1441 ret = check_kill_permission(sig, info, p);
1445 ret = do_send_sig_info(sig, info, p, type);
1451 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1452 * control characters do (^C, ^Z etc)
1453 * - the caller must hold at least a readlock on tasklist_lock
1455 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1457 struct task_struct *p = NULL;
1458 int retval, success;
1462 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1463 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1466 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1467 return success ? 0 : retval;
1470 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1473 struct task_struct *p;
1477 p = pid_task(pid, PIDTYPE_PID);
1479 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1481 if (likely(!p || error != -ESRCH))
1485 * The task was unhashed in between, try again. If it
1486 * is dead, pid_task() will return NULL, if we race with
1487 * de_thread() it will find the new leader.
1492 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1496 error = kill_pid_info(sig, info, find_vpid(pid));
1501 static inline bool kill_as_cred_perm(const struct cred *cred,
1502 struct task_struct *target)
1504 const struct cred *pcred = __task_cred(target);
1506 return uid_eq(cred->euid, pcred->suid) ||
1507 uid_eq(cred->euid, pcred->uid) ||
1508 uid_eq(cred->uid, pcred->suid) ||
1509 uid_eq(cred->uid, pcred->uid);
1513 * The usb asyncio usage of siginfo is wrong. The glibc support
1514 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1515 * AKA after the generic fields:
1516 * kernel_pid_t si_pid;
1517 * kernel_uid32_t si_uid;
1518 * sigval_t si_value;
1520 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1521 * after the generic fields is:
1522 * void __user *si_addr;
1524 * This is a practical problem when there is a 64bit big endian kernel
1525 * and a 32bit userspace. As the 32bit address will encoded in the low
1526 * 32bits of the pointer. Those low 32bits will be stored at higher
1527 * address than appear in a 32 bit pointer. So userspace will not
1528 * see the address it was expecting for it's completions.
1530 * There is nothing in the encoding that can allow
1531 * copy_siginfo_to_user32 to detect this confusion of formats, so
1532 * handle this by requiring the caller of kill_pid_usb_asyncio to
1533 * notice when this situration takes place and to store the 32bit
1534 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1537 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1538 struct pid *pid, const struct cred *cred)
1540 struct kernel_siginfo info;
1541 struct task_struct *p;
1542 unsigned long flags;
1545 if (!valid_signal(sig))
1548 clear_siginfo(&info);
1549 info.si_signo = sig;
1550 info.si_errno = errno;
1551 info.si_code = SI_ASYNCIO;
1552 *((sigval_t *)&info.si_pid) = addr;
1555 p = pid_task(pid, PIDTYPE_PID);
1560 if (!kill_as_cred_perm(cred, p)) {
1564 ret = security_task_kill(p, &info, sig, cred);
1569 if (lock_task_sighand(p, &flags)) {
1570 ret = __send_signal(sig, &info, p, PIDTYPE_TGID, false);
1571 unlock_task_sighand(p, &flags);
1579 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1582 * kill_something_info() interprets pid in interesting ways just like kill(2).
1584 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1585 * is probably wrong. Should make it like BSD or SYSV.
1588 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1593 return kill_proc_info(sig, info, pid);
1595 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1599 read_lock(&tasklist_lock);
1601 ret = __kill_pgrp_info(sig, info,
1602 pid ? find_vpid(-pid) : task_pgrp(current));
1604 int retval = 0, count = 0;
1605 struct task_struct * p;
1607 for_each_process(p) {
1608 if (task_pid_vnr(p) > 1 &&
1609 !same_thread_group(p, current)) {
1610 int err = group_send_sig_info(sig, info, p,
1617 ret = count ? retval : -ESRCH;
1619 read_unlock(&tasklist_lock);
1625 * These are for backward compatibility with the rest of the kernel source.
1628 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1631 * Make sure legacy kernel users don't send in bad values
1632 * (normal paths check this in check_kill_permission).
1634 if (!valid_signal(sig))
1637 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1639 EXPORT_SYMBOL(send_sig_info);
1641 #define __si_special(priv) \
1642 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1645 send_sig(int sig, struct task_struct *p, int priv)
1647 return send_sig_info(sig, __si_special(priv), p);
1649 EXPORT_SYMBOL(send_sig);
1651 void force_sig(int sig)
1653 struct kernel_siginfo info;
1655 clear_siginfo(&info);
1656 info.si_signo = sig;
1658 info.si_code = SI_KERNEL;
1661 force_sig_info(&info);
1663 EXPORT_SYMBOL(force_sig);
1665 void force_fatal_sig(int sig)
1667 struct kernel_siginfo info;
1669 clear_siginfo(&info);
1670 info.si_signo = sig;
1672 info.si_code = SI_KERNEL;
1675 force_sig_info_to_task(&info, current, HANDLER_SIG_DFL);
1678 void force_exit_sig(int sig)
1680 struct kernel_siginfo info;
1682 clear_siginfo(&info);
1683 info.si_signo = sig;
1685 info.si_code = SI_KERNEL;
1688 force_sig_info_to_task(&info, current, HANDLER_EXIT);
1692 * When things go south during signal handling, we
1693 * will force a SIGSEGV. And if the signal that caused
1694 * the problem was already a SIGSEGV, we'll want to
1695 * make sure we don't even try to deliver the signal..
1697 void force_sigsegv(int sig)
1700 force_fatal_sig(SIGSEGV);
1705 int force_sig_fault_to_task(int sig, int code, void __user *addr
1706 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1707 , struct task_struct *t)
1709 struct kernel_siginfo info;
1711 clear_siginfo(&info);
1712 info.si_signo = sig;
1714 info.si_code = code;
1715 info.si_addr = addr;
1718 info.si_flags = flags;
1721 return force_sig_info_to_task(&info, t, HANDLER_CURRENT);
1724 int force_sig_fault(int sig, int code, void __user *addr
1725 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1727 return force_sig_fault_to_task(sig, code, addr
1728 ___ARCH_SI_IA64(imm, flags, isr), current);
1731 int send_sig_fault(int sig, int code, void __user *addr
1732 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1733 , struct task_struct *t)
1735 struct kernel_siginfo info;
1737 clear_siginfo(&info);
1738 info.si_signo = sig;
1740 info.si_code = code;
1741 info.si_addr = addr;
1744 info.si_flags = flags;
1747 return send_sig_info(info.si_signo, &info, t);
1750 int force_sig_mceerr(int code, void __user *addr, short lsb)
1752 struct kernel_siginfo info;
1754 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1755 clear_siginfo(&info);
1756 info.si_signo = SIGBUS;
1758 info.si_code = code;
1759 info.si_addr = addr;
1760 info.si_addr_lsb = lsb;
1761 return force_sig_info(&info);
1764 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1766 struct kernel_siginfo info;
1768 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1769 clear_siginfo(&info);
1770 info.si_signo = SIGBUS;
1772 info.si_code = code;
1773 info.si_addr = addr;
1774 info.si_addr_lsb = lsb;
1775 return send_sig_info(info.si_signo, &info, t);
1777 EXPORT_SYMBOL(send_sig_mceerr);
1779 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1781 struct kernel_siginfo info;
1783 clear_siginfo(&info);
1784 info.si_signo = SIGSEGV;
1786 info.si_code = SEGV_BNDERR;
1787 info.si_addr = addr;
1788 info.si_lower = lower;
1789 info.si_upper = upper;
1790 return force_sig_info(&info);
1794 int force_sig_pkuerr(void __user *addr, u32 pkey)
1796 struct kernel_siginfo info;
1798 clear_siginfo(&info);
1799 info.si_signo = SIGSEGV;
1801 info.si_code = SEGV_PKUERR;
1802 info.si_addr = addr;
1803 info.si_pkey = pkey;
1804 return force_sig_info(&info);
1808 int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
1810 struct kernel_siginfo info;
1812 clear_siginfo(&info);
1813 info.si_signo = SIGTRAP;
1815 info.si_code = TRAP_PERF;
1816 info.si_addr = addr;
1817 info.si_perf_data = sig_data;
1818 info.si_perf_type = type;
1821 * Signals generated by perf events should not terminate the whole
1822 * process if SIGTRAP is blocked, however, delivering the signal
1823 * asynchronously is better than not delivering at all. But tell user
1824 * space if the signal was asynchronous, so it can clearly be
1825 * distinguished from normal synchronous ones.
1827 info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ?
1828 TRAP_PERF_FLAG_ASYNC :
1831 return send_sig_info(info.si_signo, &info, current);
1835 * force_sig_seccomp - signals the task to allow in-process syscall emulation
1836 * @syscall: syscall number to send to userland
1837 * @reason: filter-supplied reason code to send to userland (via si_errno)
1838 * @force_coredump: true to trigger a coredump
1840 * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
1842 int force_sig_seccomp(int syscall, int reason, bool force_coredump)
1844 struct kernel_siginfo info;
1846 clear_siginfo(&info);
1847 info.si_signo = SIGSYS;
1848 info.si_code = SYS_SECCOMP;
1849 info.si_call_addr = (void __user *)KSTK_EIP(current);
1850 info.si_errno = reason;
1851 info.si_arch = syscall_get_arch(current);
1852 info.si_syscall = syscall;
1853 return force_sig_info_to_task(&info, current,
1854 force_coredump ? HANDLER_EXIT : HANDLER_CURRENT);
1857 /* For the crazy architectures that include trap information in
1858 * the errno field, instead of an actual errno value.
1860 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1862 struct kernel_siginfo info;
1864 clear_siginfo(&info);
1865 info.si_signo = SIGTRAP;
1866 info.si_errno = errno;
1867 info.si_code = TRAP_HWBKPT;
1868 info.si_addr = addr;
1869 return force_sig_info(&info);
1872 /* For the rare architectures that include trap information using
1875 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
1877 struct kernel_siginfo info;
1879 clear_siginfo(&info);
1880 info.si_signo = sig;
1882 info.si_code = code;
1883 info.si_addr = addr;
1884 info.si_trapno = trapno;
1885 return force_sig_info(&info);
1888 /* For the rare architectures that include trap information using
1891 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
1892 struct task_struct *t)
1894 struct kernel_siginfo info;
1896 clear_siginfo(&info);
1897 info.si_signo = sig;
1899 info.si_code = code;
1900 info.si_addr = addr;
1901 info.si_trapno = trapno;
1902 return send_sig_info(info.si_signo, &info, t);
1905 int kill_pgrp(struct pid *pid, int sig, int priv)
1909 read_lock(&tasklist_lock);
1910 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1911 read_unlock(&tasklist_lock);
1915 EXPORT_SYMBOL(kill_pgrp);
1917 int kill_pid(struct pid *pid, int sig, int priv)
1919 return kill_pid_info(sig, __si_special(priv), pid);
1921 EXPORT_SYMBOL(kill_pid);
1924 * These functions support sending signals using preallocated sigqueue
1925 * structures. This is needed "because realtime applications cannot
1926 * afford to lose notifications of asynchronous events, like timer
1927 * expirations or I/O completions". In the case of POSIX Timers
1928 * we allocate the sigqueue structure from the timer_create. If this
1929 * allocation fails we are able to report the failure to the application
1930 * with an EAGAIN error.
1932 struct sigqueue *sigqueue_alloc(void)
1934 return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
1937 void sigqueue_free(struct sigqueue *q)
1939 unsigned long flags;
1940 spinlock_t *lock = ¤t->sighand->siglock;
1942 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1944 * We must hold ->siglock while testing q->list
1945 * to serialize with collect_signal() or with
1946 * __exit_signal()->flush_sigqueue().
1948 spin_lock_irqsave(lock, flags);
1949 q->flags &= ~SIGQUEUE_PREALLOC;
1951 * If it is queued it will be freed when dequeued,
1952 * like the "regular" sigqueue.
1954 if (!list_empty(&q->list))
1956 spin_unlock_irqrestore(lock, flags);
1962 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1964 int sig = q->info.si_signo;
1965 struct sigpending *pending;
1966 struct task_struct *t;
1967 unsigned long flags;
1970 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1974 t = pid_task(pid, type);
1975 if (!t || !likely(lock_task_sighand(t, &flags)))
1978 ret = 1; /* the signal is ignored */
1979 result = TRACE_SIGNAL_IGNORED;
1980 if (!prepare_signal(sig, t, false))
1984 if (unlikely(!list_empty(&q->list))) {
1986 * If an SI_TIMER entry is already queue just increment
1987 * the overrun count.
1989 BUG_ON(q->info.si_code != SI_TIMER);
1990 q->info.si_overrun++;
1991 result = TRACE_SIGNAL_ALREADY_PENDING;
1994 q->info.si_overrun = 0;
1996 signalfd_notify(t, sig);
1997 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1998 list_add_tail(&q->list, &pending->list);
1999 sigaddset(&pending->signal, sig);
2000 complete_signal(sig, t, type);
2001 result = TRACE_SIGNAL_DELIVERED;
2003 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
2004 unlock_task_sighand(t, &flags);
2010 static void do_notify_pidfd(struct task_struct *task)
2014 WARN_ON(task->exit_state == 0);
2015 pid = task_pid(task);
2016 wake_up_all(&pid->wait_pidfd);
2020 * Let a parent know about the death of a child.
2021 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
2023 * Returns true if our parent ignored us and so we've switched to
2026 bool do_notify_parent(struct task_struct *tsk, int sig)
2028 struct kernel_siginfo info;
2029 unsigned long flags;
2030 struct sighand_struct *psig;
2031 bool autoreap = false;
2036 /* do_notify_parent_cldstop should have been called instead. */
2037 BUG_ON(task_is_stopped_or_traced(tsk));
2039 BUG_ON(!tsk->ptrace &&
2040 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
2042 /* Wake up all pidfd waiters */
2043 do_notify_pidfd(tsk);
2045 if (sig != SIGCHLD) {
2047 * This is only possible if parent == real_parent.
2048 * Check if it has changed security domain.
2050 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
2054 clear_siginfo(&info);
2055 info.si_signo = sig;
2058 * We are under tasklist_lock here so our parent is tied to
2059 * us and cannot change.
2061 * task_active_pid_ns will always return the same pid namespace
2062 * until a task passes through release_task.
2064 * write_lock() currently calls preempt_disable() which is the
2065 * same as rcu_read_lock(), but according to Oleg, this is not
2066 * correct to rely on this
2069 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
2070 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
2074 task_cputime(tsk, &utime, &stime);
2075 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
2076 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
2078 info.si_status = tsk->exit_code & 0x7f;
2079 if (tsk->exit_code & 0x80)
2080 info.si_code = CLD_DUMPED;
2081 else if (tsk->exit_code & 0x7f)
2082 info.si_code = CLD_KILLED;
2084 info.si_code = CLD_EXITED;
2085 info.si_status = tsk->exit_code >> 8;
2088 psig = tsk->parent->sighand;
2089 spin_lock_irqsave(&psig->siglock, flags);
2090 if (!tsk->ptrace && sig == SIGCHLD &&
2091 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
2092 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
2094 * We are exiting and our parent doesn't care. POSIX.1
2095 * defines special semantics for setting SIGCHLD to SIG_IGN
2096 * or setting the SA_NOCLDWAIT flag: we should be reaped
2097 * automatically and not left for our parent's wait4 call.
2098 * Rather than having the parent do it as a magic kind of
2099 * signal handler, we just set this to tell do_exit that we
2100 * can be cleaned up without becoming a zombie. Note that
2101 * we still call __wake_up_parent in this case, because a
2102 * blocked sys_wait4 might now return -ECHILD.
2104 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
2105 * is implementation-defined: we do (if you don't want
2106 * it, just use SIG_IGN instead).
2109 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
2113 * Send with __send_signal as si_pid and si_uid are in the
2114 * parent's namespaces.
2116 if (valid_signal(sig) && sig)
2117 __send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false);
2118 __wake_up_parent(tsk, tsk->parent);
2119 spin_unlock_irqrestore(&psig->siglock, flags);
2125 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2126 * @tsk: task reporting the state change
2127 * @for_ptracer: the notification is for ptracer
2128 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2130 * Notify @tsk's parent that the stopped/continued state has changed. If
2131 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2132 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2135 * Must be called with tasklist_lock at least read locked.
2137 static void do_notify_parent_cldstop(struct task_struct *tsk,
2138 bool for_ptracer, int why)
2140 struct kernel_siginfo info;
2141 unsigned long flags;
2142 struct task_struct *parent;
2143 struct sighand_struct *sighand;
2147 parent = tsk->parent;
2149 tsk = tsk->group_leader;
2150 parent = tsk->real_parent;
2153 clear_siginfo(&info);
2154 info.si_signo = SIGCHLD;
2157 * see comment in do_notify_parent() about the following 4 lines
2160 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2161 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2164 task_cputime(tsk, &utime, &stime);
2165 info.si_utime = nsec_to_clock_t(utime);
2166 info.si_stime = nsec_to_clock_t(stime);
2171 info.si_status = SIGCONT;
2174 info.si_status = tsk->signal->group_exit_code & 0x7f;
2177 info.si_status = tsk->exit_code & 0x7f;
2183 sighand = parent->sighand;
2184 spin_lock_irqsave(&sighand->siglock, flags);
2185 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2186 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2187 __group_send_sig_info(SIGCHLD, &info, parent);
2189 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2191 __wake_up_parent(tsk, parent);
2192 spin_unlock_irqrestore(&sighand->siglock, flags);
2196 * This must be called with current->sighand->siglock held.
2198 * This should be the path for all ptrace stops.
2199 * We always set current->last_siginfo while stopped here.
2200 * That makes it a way to test a stopped process for
2201 * being ptrace-stopped vs being job-control-stopped.
2203 * Returns the signal the ptracer requested the code resume
2204 * with. If the code did not stop because the tracer is gone,
2205 * the stop signal remains unchanged unless clear_code.
2207 static int ptrace_stop(int exit_code, int why, int clear_code,
2208 unsigned long message, kernel_siginfo_t *info)
2209 __releases(¤t->sighand->siglock)
2210 __acquires(¤t->sighand->siglock)
2212 bool gstop_done = false;
2213 bool read_code = true;
2215 if (arch_ptrace_stop_needed()) {
2217 * The arch code has something special to do before a
2218 * ptrace stop. This is allowed to block, e.g. for faults
2219 * on user stack pages. We can't keep the siglock while
2220 * calling arch_ptrace_stop, so we must release it now.
2221 * To preserve proper semantics, we must do this before
2222 * any signal bookkeeping like checking group_stop_count.
2224 spin_unlock_irq(¤t->sighand->siglock);
2226 spin_lock_irq(¤t->sighand->siglock);
2230 * schedule() will not sleep if there is a pending signal that
2231 * can awaken the task.
2233 set_special_state(TASK_TRACED);
2236 * We're committing to trapping. TRACED should be visible before
2237 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2238 * Also, transition to TRACED and updates to ->jobctl should be
2239 * atomic with respect to siglock and should be done after the arch
2240 * hook as siglock is released and regrabbed across it.
2245 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2247 * set_current_state() smp_wmb();
2249 * wait_task_stopped()
2250 * task_stopped_code()
2251 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2255 current->ptrace_message = message;
2256 current->last_siginfo = info;
2257 current->exit_code = exit_code;
2260 * If @why is CLD_STOPPED, we're trapping to participate in a group
2261 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2262 * across siglock relocks since INTERRUPT was scheduled, PENDING
2263 * could be clear now. We act as if SIGCONT is received after
2264 * TASK_TRACED is entered - ignore it.
2266 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2267 gstop_done = task_participate_group_stop(current);
2269 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2270 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2271 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2272 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2274 /* entering a trap, clear TRAPPING */
2275 task_clear_jobctl_trapping(current);
2277 spin_unlock_irq(¤t->sighand->siglock);
2278 read_lock(&tasklist_lock);
2279 if (likely(current->ptrace)) {
2281 * Notify parents of the stop.
2283 * While ptraced, there are two parents - the ptracer and
2284 * the real_parent of the group_leader. The ptracer should
2285 * know about every stop while the real parent is only
2286 * interested in the completion of group stop. The states
2287 * for the two don't interact with each other. Notify
2288 * separately unless they're gonna be duplicates.
2290 do_notify_parent_cldstop(current, true, why);
2291 if (gstop_done && ptrace_reparented(current))
2292 do_notify_parent_cldstop(current, false, why);
2295 * Don't want to allow preemption here, because
2296 * sys_ptrace() needs this task to be inactive.
2298 * XXX: implement read_unlock_no_resched().
2301 read_unlock(&tasklist_lock);
2302 cgroup_enter_frozen();
2303 preempt_enable_no_resched();
2304 freezable_schedule();
2305 cgroup_leave_frozen(true);
2308 * By the time we got the lock, our tracer went away.
2309 * Don't drop the lock yet, another tracer may come.
2311 * If @gstop_done, the ptracer went away between group stop
2312 * completion and here. During detach, it would have set
2313 * JOBCTL_STOP_PENDING on us and we'll re-enter
2314 * TASK_STOPPED in do_signal_stop() on return, so notifying
2315 * the real parent of the group stop completion is enough.
2318 do_notify_parent_cldstop(current, false, why);
2320 /* tasklist protects us from ptrace_freeze_traced() */
2321 __set_current_state(TASK_RUNNING);
2325 read_unlock(&tasklist_lock);
2329 * We are back. Now reacquire the siglock before touching
2330 * last_siginfo, so that we are sure to have synchronized with
2331 * any signal-sending on another CPU that wants to examine it.
2333 spin_lock_irq(¤t->sighand->siglock);
2335 exit_code = current->exit_code;
2336 current->last_siginfo = NULL;
2337 current->ptrace_message = 0;
2338 current->exit_code = 0;
2340 /* LISTENING can be set only during STOP traps, clear it */
2341 current->jobctl &= ~JOBCTL_LISTENING;
2344 * Queued signals ignored us while we were stopped for tracing.
2345 * So check for any that we should take before resuming user mode.
2346 * This sets TIF_SIGPENDING, but never clears it.
2348 recalc_sigpending_tsk(current);
2352 static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message)
2354 kernel_siginfo_t info;
2356 clear_siginfo(&info);
2357 info.si_signo = signr;
2358 info.si_code = exit_code;
2359 info.si_pid = task_pid_vnr(current);
2360 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2362 /* Let the debugger run. */
2363 return ptrace_stop(exit_code, why, 1, message, &info);
2366 int ptrace_notify(int exit_code, unsigned long message)
2370 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2371 if (unlikely(task_work_pending(current)))
2374 spin_lock_irq(¤t->sighand->siglock);
2375 signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message);
2376 spin_unlock_irq(¤t->sighand->siglock);
2381 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2382 * @signr: signr causing group stop if initiating
2384 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2385 * and participate in it. If already set, participate in the existing
2386 * group stop. If participated in a group stop (and thus slept), %true is
2387 * returned with siglock released.
2389 * If ptraced, this function doesn't handle stop itself. Instead,
2390 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2391 * untouched. The caller must ensure that INTERRUPT trap handling takes
2392 * places afterwards.
2395 * Must be called with @current->sighand->siglock held, which is released
2399 * %false if group stop is already cancelled or ptrace trap is scheduled.
2400 * %true if participated in group stop.
2402 static bool do_signal_stop(int signr)
2403 __releases(¤t->sighand->siglock)
2405 struct signal_struct *sig = current->signal;
2407 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2408 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2409 struct task_struct *t;
2411 /* signr will be recorded in task->jobctl for retries */
2412 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2414 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2415 unlikely(sig->flags & SIGNAL_GROUP_EXIT) ||
2416 unlikely(sig->group_exec_task))
2419 * There is no group stop already in progress. We must
2422 * While ptraced, a task may be resumed while group stop is
2423 * still in effect and then receive a stop signal and
2424 * initiate another group stop. This deviates from the
2425 * usual behavior as two consecutive stop signals can't
2426 * cause two group stops when !ptraced. That is why we
2427 * also check !task_is_stopped(t) below.
2429 * The condition can be distinguished by testing whether
2430 * SIGNAL_STOP_STOPPED is already set. Don't generate
2431 * group_exit_code in such case.
2433 * This is not necessary for SIGNAL_STOP_CONTINUED because
2434 * an intervening stop signal is required to cause two
2435 * continued events regardless of ptrace.
2437 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2438 sig->group_exit_code = signr;
2440 sig->group_stop_count = 0;
2442 if (task_set_jobctl_pending(current, signr | gstop))
2443 sig->group_stop_count++;
2446 while_each_thread(current, t) {
2448 * Setting state to TASK_STOPPED for a group
2449 * stop is always done with the siglock held,
2450 * so this check has no races.
2452 if (!task_is_stopped(t) &&
2453 task_set_jobctl_pending(t, signr | gstop)) {
2454 sig->group_stop_count++;
2455 if (likely(!(t->ptrace & PT_SEIZED)))
2456 signal_wake_up(t, 0);
2458 ptrace_trap_notify(t);
2463 if (likely(!current->ptrace)) {
2467 * If there are no other threads in the group, or if there
2468 * is a group stop in progress and we are the last to stop,
2469 * report to the parent.
2471 if (task_participate_group_stop(current))
2472 notify = CLD_STOPPED;
2474 set_special_state(TASK_STOPPED);
2475 spin_unlock_irq(¤t->sighand->siglock);
2478 * Notify the parent of the group stop completion. Because
2479 * we're not holding either the siglock or tasklist_lock
2480 * here, ptracer may attach inbetween; however, this is for
2481 * group stop and should always be delivered to the real
2482 * parent of the group leader. The new ptracer will get
2483 * its notification when this task transitions into
2487 read_lock(&tasklist_lock);
2488 do_notify_parent_cldstop(current, false, notify);
2489 read_unlock(&tasklist_lock);
2492 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2493 cgroup_enter_frozen();
2494 freezable_schedule();
2498 * While ptraced, group stop is handled by STOP trap.
2499 * Schedule it and let the caller deal with it.
2501 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2507 * do_jobctl_trap - take care of ptrace jobctl traps
2509 * When PT_SEIZED, it's used for both group stop and explicit
2510 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2511 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2512 * the stop signal; otherwise, %SIGTRAP.
2514 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2515 * number as exit_code and no siginfo.
2518 * Must be called with @current->sighand->siglock held, which may be
2519 * released and re-acquired before returning with intervening sleep.
2521 static void do_jobctl_trap(void)
2523 struct signal_struct *signal = current->signal;
2524 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2526 if (current->ptrace & PT_SEIZED) {
2527 if (!signal->group_stop_count &&
2528 !(signal->flags & SIGNAL_STOP_STOPPED))
2530 WARN_ON_ONCE(!signr);
2531 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2534 WARN_ON_ONCE(!signr);
2535 ptrace_stop(signr, CLD_STOPPED, 0, 0, NULL);
2540 * do_freezer_trap - handle the freezer jobctl trap
2542 * Puts the task into frozen state, if only the task is not about to quit.
2543 * In this case it drops JOBCTL_TRAP_FREEZE.
2546 * Must be called with @current->sighand->siglock held,
2547 * which is always released before returning.
2549 static void do_freezer_trap(void)
2550 __releases(¤t->sighand->siglock)
2553 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2554 * let's make another loop to give it a chance to be handled.
2555 * In any case, we'll return back.
2557 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2558 JOBCTL_TRAP_FREEZE) {
2559 spin_unlock_irq(¤t->sighand->siglock);
2564 * Now we're sure that there is no pending fatal signal and no
2565 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2566 * immediately (if there is a non-fatal signal pending), and
2567 * put the task into sleep.
2569 __set_current_state(TASK_INTERRUPTIBLE);
2570 clear_thread_flag(TIF_SIGPENDING);
2571 spin_unlock_irq(¤t->sighand->siglock);
2572 cgroup_enter_frozen();
2573 freezable_schedule();
2576 static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type)
2579 * We do not check sig_kernel_stop(signr) but set this marker
2580 * unconditionally because we do not know whether debugger will
2581 * change signr. This flag has no meaning unless we are going
2582 * to stop after return from ptrace_stop(). In this case it will
2583 * be checked in do_signal_stop(), we should only stop if it was
2584 * not cleared by SIGCONT while we were sleeping. See also the
2585 * comment in dequeue_signal().
2587 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2588 signr = ptrace_stop(signr, CLD_TRAPPED, 0, 0, info);
2590 /* We're back. Did the debugger cancel the sig? */
2595 * Update the siginfo structure if the signal has
2596 * changed. If the debugger wanted something
2597 * specific in the siginfo structure then it should
2598 * have updated *info via PTRACE_SETSIGINFO.
2600 if (signr != info->si_signo) {
2601 clear_siginfo(info);
2602 info->si_signo = signr;
2604 info->si_code = SI_USER;
2606 info->si_pid = task_pid_vnr(current->parent);
2607 info->si_uid = from_kuid_munged(current_user_ns(),
2608 task_uid(current->parent));
2612 /* If the (new) signal is now blocked, requeue it. */
2613 if (sigismember(¤t->blocked, signr) ||
2614 fatal_signal_pending(current)) {
2615 send_signal(signr, info, current, type);
2622 static void hide_si_addr_tag_bits(struct ksignal *ksig)
2624 switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
2626 case SIL_FAULT_TRAPNO:
2627 case SIL_FAULT_MCEERR:
2628 case SIL_FAULT_BNDERR:
2629 case SIL_FAULT_PKUERR:
2630 case SIL_FAULT_PERF_EVENT:
2631 ksig->info.si_addr = arch_untagged_si_addr(
2632 ksig->info.si_addr, ksig->sig, ksig->info.si_code);
2644 bool get_signal(struct ksignal *ksig)
2646 struct sighand_struct *sighand = current->sighand;
2647 struct signal_struct *signal = current->signal;
2650 clear_notify_signal();
2651 if (unlikely(task_work_pending(current)))
2654 if (!task_sigpending(current))
2657 if (unlikely(uprobe_deny_signal()))
2661 * Do this once, we can't return to user-mode if freezing() == T.
2662 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2663 * thus do not need another check after return.
2668 spin_lock_irq(&sighand->siglock);
2671 * Every stopped thread goes here after wakeup. Check to see if
2672 * we should notify the parent, prepare_signal(SIGCONT) encodes
2673 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2675 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2678 if (signal->flags & SIGNAL_CLD_CONTINUED)
2679 why = CLD_CONTINUED;
2683 signal->flags &= ~SIGNAL_CLD_MASK;
2685 spin_unlock_irq(&sighand->siglock);
2688 * Notify the parent that we're continuing. This event is
2689 * always per-process and doesn't make whole lot of sense
2690 * for ptracers, who shouldn't consume the state via
2691 * wait(2) either, but, for backward compatibility, notify
2692 * the ptracer of the group leader too unless it's gonna be
2695 read_lock(&tasklist_lock);
2696 do_notify_parent_cldstop(current, false, why);
2698 if (ptrace_reparented(current->group_leader))
2699 do_notify_parent_cldstop(current->group_leader,
2701 read_unlock(&tasklist_lock);
2707 struct k_sigaction *ka;
2710 /* Has this task already been marked for death? */
2711 if ((signal->flags & SIGNAL_GROUP_EXIT) ||
2712 signal->group_exec_task) {
2713 ksig->info.si_signo = signr = SIGKILL;
2714 sigdelset(¤t->pending.signal, SIGKILL);
2715 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2716 &sighand->action[SIGKILL - 1]);
2717 recalc_sigpending();
2721 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2725 if (unlikely(current->jobctl &
2726 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2727 if (current->jobctl & JOBCTL_TRAP_MASK) {
2729 spin_unlock_irq(&sighand->siglock);
2730 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2737 * If the task is leaving the frozen state, let's update
2738 * cgroup counters and reset the frozen bit.
2740 if (unlikely(cgroup_task_frozen(current))) {
2741 spin_unlock_irq(&sighand->siglock);
2742 cgroup_leave_frozen(false);
2747 * Signals generated by the execution of an instruction
2748 * need to be delivered before any other pending signals
2749 * so that the instruction pointer in the signal stack
2750 * frame points to the faulting instruction.
2753 signr = dequeue_synchronous_signal(&ksig->info);
2755 signr = dequeue_signal(current, ¤t->blocked,
2756 &ksig->info, &type);
2759 break; /* will return 0 */
2761 if (unlikely(current->ptrace) && (signr != SIGKILL) &&
2762 !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) {
2763 signr = ptrace_signal(signr, &ksig->info, type);
2768 ka = &sighand->action[signr-1];
2770 /* Trace actually delivered signals. */
2771 trace_signal_deliver(signr, &ksig->info, ka);
2773 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2775 if (ka->sa.sa_handler != SIG_DFL) {
2776 /* Run the handler. */
2779 if (ka->sa.sa_flags & SA_ONESHOT)
2780 ka->sa.sa_handler = SIG_DFL;
2782 break; /* will return non-zero "signr" value */
2786 * Now we are doing the default action for this signal.
2788 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2792 * Global init gets no signals it doesn't want.
2793 * Container-init gets no signals it doesn't want from same
2796 * Note that if global/container-init sees a sig_kernel_only()
2797 * signal here, the signal must have been generated internally
2798 * or must have come from an ancestor namespace. In either
2799 * case, the signal cannot be dropped.
2801 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2802 !sig_kernel_only(signr))
2805 if (sig_kernel_stop(signr)) {
2807 * The default action is to stop all threads in
2808 * the thread group. The job control signals
2809 * do nothing in an orphaned pgrp, but SIGSTOP
2810 * always works. Note that siglock needs to be
2811 * dropped during the call to is_orphaned_pgrp()
2812 * because of lock ordering with tasklist_lock.
2813 * This allows an intervening SIGCONT to be posted.
2814 * We need to check for that and bail out if necessary.
2816 if (signr != SIGSTOP) {
2817 spin_unlock_irq(&sighand->siglock);
2819 /* signals can be posted during this window */
2821 if (is_current_pgrp_orphaned())
2824 spin_lock_irq(&sighand->siglock);
2827 if (likely(do_signal_stop(ksig->info.si_signo))) {
2828 /* It released the siglock. */
2833 * We didn't actually stop, due to a race
2834 * with SIGCONT or something like that.
2840 spin_unlock_irq(&sighand->siglock);
2841 if (unlikely(cgroup_task_frozen(current)))
2842 cgroup_leave_frozen(true);
2845 * Anything else is fatal, maybe with a core dump.
2847 current->flags |= PF_SIGNALED;
2849 if (sig_kernel_coredump(signr)) {
2850 if (print_fatal_signals)
2851 print_fatal_signal(ksig->info.si_signo);
2852 proc_coredump_connector(current);
2854 * If it was able to dump core, this kills all
2855 * other threads in the group and synchronizes with
2856 * their demise. If we lost the race with another
2857 * thread getting here, it set group_exit_code
2858 * first and our do_group_exit call below will use
2859 * that value and ignore the one we pass it.
2861 do_coredump(&ksig->info);
2865 * PF_IO_WORKER threads will catch and exit on fatal signals
2866 * themselves. They have cleanup that must be performed, so
2867 * we cannot call do_exit() on their behalf.
2869 if (current->flags & PF_IO_WORKER)
2873 * Death signals, no core dump.
2875 do_group_exit(ksig->info.si_signo);
2878 spin_unlock_irq(&sighand->siglock);
2882 if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
2883 hide_si_addr_tag_bits(ksig);
2885 return ksig->sig > 0;
2889 * signal_delivered - called after signal delivery to update blocked signals
2890 * @ksig: kernel signal struct
2891 * @stepping: nonzero if debugger single-step or block-step in use
2893 * This function should be called when a signal has successfully been
2894 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2895 * is always blocked), and the signal itself is blocked unless %SA_NODEFER
2896 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2898 static void signal_delivered(struct ksignal *ksig, int stepping)
2902 /* A signal was successfully delivered, and the
2903 saved sigmask was stored on the signal frame,
2904 and will be restored by sigreturn. So we can
2905 simply clear the restore sigmask flag. */
2906 clear_restore_sigmask();
2908 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2909 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2910 sigaddset(&blocked, ksig->sig);
2911 set_current_blocked(&blocked);
2912 if (current->sas_ss_flags & SS_AUTODISARM)
2913 sas_ss_reset(current);
2915 ptrace_notify(SIGTRAP, 0);
2918 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2921 force_sigsegv(ksig->sig);
2923 signal_delivered(ksig, stepping);
2927 * It could be that complete_signal() picked us to notify about the
2928 * group-wide signal. Other threads should be notified now to take
2929 * the shared signals in @which since we will not.
2931 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2934 struct task_struct *t;
2936 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2937 if (sigisemptyset(&retarget))
2941 while_each_thread(tsk, t) {
2942 if (t->flags & PF_EXITING)
2945 if (!has_pending_signals(&retarget, &t->blocked))
2947 /* Remove the signals this thread can handle. */
2948 sigandsets(&retarget, &retarget, &t->blocked);
2950 if (!task_sigpending(t))
2951 signal_wake_up(t, 0);
2953 if (sigisemptyset(&retarget))
2958 void exit_signals(struct task_struct *tsk)
2964 * @tsk is about to have PF_EXITING set - lock out users which
2965 * expect stable threadgroup.
2967 cgroup_threadgroup_change_begin(tsk);
2969 if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
2970 tsk->flags |= PF_EXITING;
2971 cgroup_threadgroup_change_end(tsk);
2975 spin_lock_irq(&tsk->sighand->siglock);
2977 * From now this task is not visible for group-wide signals,
2978 * see wants_signal(), do_signal_stop().
2980 tsk->flags |= PF_EXITING;
2982 cgroup_threadgroup_change_end(tsk);
2984 if (!task_sigpending(tsk))
2987 unblocked = tsk->blocked;
2988 signotset(&unblocked);
2989 retarget_shared_pending(tsk, &unblocked);
2991 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2992 task_participate_group_stop(tsk))
2993 group_stop = CLD_STOPPED;
2995 spin_unlock_irq(&tsk->sighand->siglock);
2998 * If group stop has completed, deliver the notification. This
2999 * should always go to the real parent of the group leader.
3001 if (unlikely(group_stop)) {
3002 read_lock(&tasklist_lock);
3003 do_notify_parent_cldstop(tsk, false, group_stop);
3004 read_unlock(&tasklist_lock);
3009 * System call entry points.
3013 * sys_restart_syscall - restart a system call
3015 SYSCALL_DEFINE0(restart_syscall)
3017 struct restart_block *restart = ¤t->restart_block;
3018 return restart->fn(restart);
3021 long do_no_restart_syscall(struct restart_block *param)
3026 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
3028 if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
3029 sigset_t newblocked;
3030 /* A set of now blocked but previously unblocked signals. */
3031 sigandnsets(&newblocked, newset, ¤t->blocked);
3032 retarget_shared_pending(tsk, &newblocked);
3034 tsk->blocked = *newset;
3035 recalc_sigpending();
3039 * set_current_blocked - change current->blocked mask
3042 * It is wrong to change ->blocked directly, this helper should be used
3043 * to ensure the process can't miss a shared signal we are going to block.
3045 void set_current_blocked(sigset_t *newset)
3047 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
3048 __set_current_blocked(newset);
3051 void __set_current_blocked(const sigset_t *newset)
3053 struct task_struct *tsk = current;
3056 * In case the signal mask hasn't changed, there is nothing we need
3057 * to do. The current->blocked shouldn't be modified by other task.
3059 if (sigequalsets(&tsk->blocked, newset))
3062 spin_lock_irq(&tsk->sighand->siglock);
3063 __set_task_blocked(tsk, newset);
3064 spin_unlock_irq(&tsk->sighand->siglock);
3068 * This is also useful for kernel threads that want to temporarily
3069 * (or permanently) block certain signals.
3071 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
3072 * interface happily blocks "unblockable" signals like SIGKILL
3075 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
3077 struct task_struct *tsk = current;
3080 /* Lockless, only current can change ->blocked, never from irq */
3082 *oldset = tsk->blocked;
3086 sigorsets(&newset, &tsk->blocked, set);
3089 sigandnsets(&newset, &tsk->blocked, set);
3098 __set_current_blocked(&newset);
3101 EXPORT_SYMBOL(sigprocmask);
3104 * The api helps set app-provided sigmasks.
3106 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
3107 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
3109 * Note that it does set_restore_sigmask() in advance, so it must be always
3110 * paired with restore_saved_sigmask_unless() before return from syscall.
3112 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
3118 if (sigsetsize != sizeof(sigset_t))
3120 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
3123 set_restore_sigmask();
3124 current->saved_sigmask = current->blocked;
3125 set_current_blocked(&kmask);
3130 #ifdef CONFIG_COMPAT
3131 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3138 if (sigsetsize != sizeof(compat_sigset_t))
3140 if (get_compat_sigset(&kmask, umask))
3143 set_restore_sigmask();
3144 current->saved_sigmask = current->blocked;
3145 set_current_blocked(&kmask);
3152 * sys_rt_sigprocmask - change the list of currently blocked signals
3153 * @how: whether to add, remove, or set signals
3154 * @nset: stores pending signals
3155 * @oset: previous value of signal mask if non-null
3156 * @sigsetsize: size of sigset_t type
3158 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3159 sigset_t __user *, oset, size_t, sigsetsize)
3161 sigset_t old_set, new_set;
3164 /* XXX: Don't preclude handling different sized sigset_t's. */
3165 if (sigsetsize != sizeof(sigset_t))
3168 old_set = current->blocked;
3171 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3173 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3175 error = sigprocmask(how, &new_set, NULL);
3181 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3188 #ifdef CONFIG_COMPAT
3189 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3190 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3192 sigset_t old_set = current->blocked;
3194 /* XXX: Don't preclude handling different sized sigset_t's. */
3195 if (sigsetsize != sizeof(sigset_t))
3201 if (get_compat_sigset(&new_set, nset))
3203 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3205 error = sigprocmask(how, &new_set, NULL);
3209 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3213 static void do_sigpending(sigset_t *set)
3215 spin_lock_irq(¤t->sighand->siglock);
3216 sigorsets(set, ¤t->pending.signal,
3217 ¤t->signal->shared_pending.signal);
3218 spin_unlock_irq(¤t->sighand->siglock);
3220 /* Outside the lock because only this thread touches it. */
3221 sigandsets(set, ¤t->blocked, set);
3225 * sys_rt_sigpending - examine a pending signal that has been raised
3227 * @uset: stores pending signals
3228 * @sigsetsize: size of sigset_t type or larger
3230 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3234 if (sigsetsize > sizeof(*uset))
3237 do_sigpending(&set);
3239 if (copy_to_user(uset, &set, sigsetsize))
3245 #ifdef CONFIG_COMPAT
3246 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3247 compat_size_t, sigsetsize)
3251 if (sigsetsize > sizeof(*uset))
3254 do_sigpending(&set);
3256 return put_compat_sigset(uset, &set, sigsetsize);
3260 static const struct {
3261 unsigned char limit, layout;
3263 [SIGILL] = { NSIGILL, SIL_FAULT },
3264 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3265 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3266 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3267 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3269 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3271 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3272 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3273 [SIGSYS] = { NSIGSYS, SIL_SYS },
3276 static bool known_siginfo_layout(unsigned sig, int si_code)
3278 if (si_code == SI_KERNEL)
3280 else if ((si_code > SI_USER)) {
3281 if (sig_specific_sicodes(sig)) {
3282 if (si_code <= sig_sicodes[sig].limit)
3285 else if (si_code <= NSIGPOLL)
3288 else if (si_code >= SI_DETHREAD)
3290 else if (si_code == SI_ASYNCNL)
3295 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3297 enum siginfo_layout layout = SIL_KILL;
3298 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3299 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3300 (si_code <= sig_sicodes[sig].limit)) {
3301 layout = sig_sicodes[sig].layout;
3302 /* Handle the exceptions */
3303 if ((sig == SIGBUS) &&
3304 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3305 layout = SIL_FAULT_MCEERR;
3306 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3307 layout = SIL_FAULT_BNDERR;
3309 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3310 layout = SIL_FAULT_PKUERR;
3312 else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
3313 layout = SIL_FAULT_PERF_EVENT;
3314 else if (IS_ENABLED(CONFIG_SPARC) &&
3315 (sig == SIGILL) && (si_code == ILL_ILLTRP))
3316 layout = SIL_FAULT_TRAPNO;
3317 else if (IS_ENABLED(CONFIG_ALPHA) &&
3319 ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
3320 layout = SIL_FAULT_TRAPNO;
3322 else if (si_code <= NSIGPOLL)
3325 if (si_code == SI_TIMER)
3327 else if (si_code == SI_SIGIO)
3329 else if (si_code < 0)
3335 static inline char __user *si_expansion(const siginfo_t __user *info)
3337 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3340 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3342 char __user *expansion = si_expansion(to);
3343 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3345 if (clear_user(expansion, SI_EXPANSION_SIZE))
3350 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3351 const siginfo_t __user *from)
3353 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3354 char __user *expansion = si_expansion(from);
3355 char buf[SI_EXPANSION_SIZE];
3358 * An unknown si_code might need more than
3359 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3360 * extra bytes are 0. This guarantees copy_siginfo_to_user
3361 * will return this data to userspace exactly.
3363 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3365 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3373 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3374 const siginfo_t __user *from)
3376 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3378 to->si_signo = signo;
3379 return post_copy_siginfo_from_user(to, from);
3382 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3384 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3386 return post_copy_siginfo_from_user(to, from);
3389 #ifdef CONFIG_COMPAT
3391 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3392 * @to: compat siginfo destination
3393 * @from: kernel siginfo source
3395 * Note: This function does not work properly for the SIGCHLD on x32, but
3396 * fortunately it doesn't have to. The only valid callers for this function are
3397 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3398 * The latter does not care because SIGCHLD will never cause a coredump.
3400 void copy_siginfo_to_external32(struct compat_siginfo *to,
3401 const struct kernel_siginfo *from)
3403 memset(to, 0, sizeof(*to));
3405 to->si_signo = from->si_signo;
3406 to->si_errno = from->si_errno;
3407 to->si_code = from->si_code;
3408 switch(siginfo_layout(from->si_signo, from->si_code)) {
3410 to->si_pid = from->si_pid;
3411 to->si_uid = from->si_uid;
3414 to->si_tid = from->si_tid;
3415 to->si_overrun = from->si_overrun;
3416 to->si_int = from->si_int;
3419 to->si_band = from->si_band;
3420 to->si_fd = from->si_fd;
3423 to->si_addr = ptr_to_compat(from->si_addr);
3425 case SIL_FAULT_TRAPNO:
3426 to->si_addr = ptr_to_compat(from->si_addr);
3427 to->si_trapno = from->si_trapno;
3429 case SIL_FAULT_MCEERR:
3430 to->si_addr = ptr_to_compat(from->si_addr);
3431 to->si_addr_lsb = from->si_addr_lsb;
3433 case SIL_FAULT_BNDERR:
3434 to->si_addr = ptr_to_compat(from->si_addr);
3435 to->si_lower = ptr_to_compat(from->si_lower);
3436 to->si_upper = ptr_to_compat(from->si_upper);
3438 case SIL_FAULT_PKUERR:
3439 to->si_addr = ptr_to_compat(from->si_addr);
3440 to->si_pkey = from->si_pkey;
3442 case SIL_FAULT_PERF_EVENT:
3443 to->si_addr = ptr_to_compat(from->si_addr);
3444 to->si_perf_data = from->si_perf_data;
3445 to->si_perf_type = from->si_perf_type;
3446 to->si_perf_flags = from->si_perf_flags;
3449 to->si_pid = from->si_pid;
3450 to->si_uid = from->si_uid;
3451 to->si_status = from->si_status;
3452 to->si_utime = from->si_utime;
3453 to->si_stime = from->si_stime;
3456 to->si_pid = from->si_pid;
3457 to->si_uid = from->si_uid;
3458 to->si_int = from->si_int;
3461 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3462 to->si_syscall = from->si_syscall;
3463 to->si_arch = from->si_arch;
3468 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3469 const struct kernel_siginfo *from)
3471 struct compat_siginfo new;
3473 copy_siginfo_to_external32(&new, from);
3474 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3479 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3480 const struct compat_siginfo *from)
3483 to->si_signo = from->si_signo;
3484 to->si_errno = from->si_errno;
3485 to->si_code = from->si_code;
3486 switch(siginfo_layout(from->si_signo, from->si_code)) {
3488 to->si_pid = from->si_pid;
3489 to->si_uid = from->si_uid;
3492 to->si_tid = from->si_tid;
3493 to->si_overrun = from->si_overrun;
3494 to->si_int = from->si_int;
3497 to->si_band = from->si_band;
3498 to->si_fd = from->si_fd;
3501 to->si_addr = compat_ptr(from->si_addr);
3503 case SIL_FAULT_TRAPNO:
3504 to->si_addr = compat_ptr(from->si_addr);
3505 to->si_trapno = from->si_trapno;
3507 case SIL_FAULT_MCEERR:
3508 to->si_addr = compat_ptr(from->si_addr);
3509 to->si_addr_lsb = from->si_addr_lsb;
3511 case SIL_FAULT_BNDERR:
3512 to->si_addr = compat_ptr(from->si_addr);
3513 to->si_lower = compat_ptr(from->si_lower);
3514 to->si_upper = compat_ptr(from->si_upper);
3516 case SIL_FAULT_PKUERR:
3517 to->si_addr = compat_ptr(from->si_addr);
3518 to->si_pkey = from->si_pkey;
3520 case SIL_FAULT_PERF_EVENT:
3521 to->si_addr = compat_ptr(from->si_addr);
3522 to->si_perf_data = from->si_perf_data;
3523 to->si_perf_type = from->si_perf_type;
3524 to->si_perf_flags = from->si_perf_flags;
3527 to->si_pid = from->si_pid;
3528 to->si_uid = from->si_uid;
3529 to->si_status = from->si_status;
3530 #ifdef CONFIG_X86_X32_ABI
3531 if (in_x32_syscall()) {
3532 to->si_utime = from->_sifields._sigchld_x32._utime;
3533 to->si_stime = from->_sifields._sigchld_x32._stime;
3537 to->si_utime = from->si_utime;
3538 to->si_stime = from->si_stime;
3542 to->si_pid = from->si_pid;
3543 to->si_uid = from->si_uid;
3544 to->si_int = from->si_int;
3547 to->si_call_addr = compat_ptr(from->si_call_addr);
3548 to->si_syscall = from->si_syscall;
3549 to->si_arch = from->si_arch;
3555 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3556 const struct compat_siginfo __user *ufrom)
3558 struct compat_siginfo from;
3560 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3563 from.si_signo = signo;
3564 return post_copy_siginfo_from_user32(to, &from);
3567 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3568 const struct compat_siginfo __user *ufrom)
3570 struct compat_siginfo from;
3572 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3575 return post_copy_siginfo_from_user32(to, &from);
3577 #endif /* CONFIG_COMPAT */
3580 * do_sigtimedwait - wait for queued signals specified in @which
3581 * @which: queued signals to wait for
3582 * @info: if non-null, the signal's siginfo is returned here
3583 * @ts: upper bound on process time suspension
3585 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3586 const struct timespec64 *ts)
3588 ktime_t *to = NULL, timeout = KTIME_MAX;
3589 struct task_struct *tsk = current;
3590 sigset_t mask = *which;
3595 if (!timespec64_valid(ts))
3597 timeout = timespec64_to_ktime(*ts);
3602 * Invert the set of allowed signals to get those we want to block.
3604 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3607 spin_lock_irq(&tsk->sighand->siglock);
3608 sig = dequeue_signal(tsk, &mask, info, &type);
3609 if (!sig && timeout) {
3611 * None ready, temporarily unblock those we're interested
3612 * while we are sleeping in so that we'll be awakened when
3613 * they arrive. Unblocking is always fine, we can avoid
3614 * set_current_blocked().
3616 tsk->real_blocked = tsk->blocked;
3617 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3618 recalc_sigpending();
3619 spin_unlock_irq(&tsk->sighand->siglock);
3621 __set_current_state(TASK_INTERRUPTIBLE);
3622 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3624 spin_lock_irq(&tsk->sighand->siglock);
3625 __set_task_blocked(tsk, &tsk->real_blocked);
3626 sigemptyset(&tsk->real_blocked);
3627 sig = dequeue_signal(tsk, &mask, info, &type);
3629 spin_unlock_irq(&tsk->sighand->siglock);
3633 return ret ? -EINTR : -EAGAIN;
3637 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3639 * @uthese: queued signals to wait for
3640 * @uinfo: if non-null, the signal's siginfo is returned here
3641 * @uts: upper bound on process time suspension
3642 * @sigsetsize: size of sigset_t type
3644 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3645 siginfo_t __user *, uinfo,
3646 const struct __kernel_timespec __user *, uts,
3650 struct timespec64 ts;
3651 kernel_siginfo_t info;
3654 /* XXX: Don't preclude handling different sized sigset_t's. */
3655 if (sigsetsize != sizeof(sigset_t))
3658 if (copy_from_user(&these, uthese, sizeof(these)))
3662 if (get_timespec64(&ts, uts))
3666 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3668 if (ret > 0 && uinfo) {
3669 if (copy_siginfo_to_user(uinfo, &info))
3676 #ifdef CONFIG_COMPAT_32BIT_TIME
3677 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3678 siginfo_t __user *, uinfo,
3679 const struct old_timespec32 __user *, uts,
3683 struct timespec64 ts;
3684 kernel_siginfo_t info;
3687 if (sigsetsize != sizeof(sigset_t))
3690 if (copy_from_user(&these, uthese, sizeof(these)))
3694 if (get_old_timespec32(&ts, uts))
3698 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3700 if (ret > 0 && uinfo) {
3701 if (copy_siginfo_to_user(uinfo, &info))
3709 #ifdef CONFIG_COMPAT
3710 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3711 struct compat_siginfo __user *, uinfo,
3712 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3715 struct timespec64 t;
3716 kernel_siginfo_t info;
3719 if (sigsetsize != sizeof(sigset_t))
3722 if (get_compat_sigset(&s, uthese))
3726 if (get_timespec64(&t, uts))
3730 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3732 if (ret > 0 && uinfo) {
3733 if (copy_siginfo_to_user32(uinfo, &info))
3740 #ifdef CONFIG_COMPAT_32BIT_TIME
3741 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3742 struct compat_siginfo __user *, uinfo,
3743 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3746 struct timespec64 t;
3747 kernel_siginfo_t info;
3750 if (sigsetsize != sizeof(sigset_t))
3753 if (get_compat_sigset(&s, uthese))
3757 if (get_old_timespec32(&t, uts))
3761 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3763 if (ret > 0 && uinfo) {
3764 if (copy_siginfo_to_user32(uinfo, &info))
3773 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3775 clear_siginfo(info);
3776 info->si_signo = sig;
3778 info->si_code = SI_USER;
3779 info->si_pid = task_tgid_vnr(current);
3780 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3784 * sys_kill - send a signal to a process
3785 * @pid: the PID of the process
3786 * @sig: signal to be sent
3788 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3790 struct kernel_siginfo info;
3792 prepare_kill_siginfo(sig, &info);
3794 return kill_something_info(sig, &info, pid);
3798 * Verify that the signaler and signalee either are in the same pid namespace
3799 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3802 static bool access_pidfd_pidns(struct pid *pid)
3804 struct pid_namespace *active = task_active_pid_ns(current);
3805 struct pid_namespace *p = ns_of_pid(pid);
3818 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
3819 siginfo_t __user *info)
3821 #ifdef CONFIG_COMPAT
3823 * Avoid hooking up compat syscalls and instead handle necessary
3824 * conversions here. Note, this is a stop-gap measure and should not be
3825 * considered a generic solution.
3827 if (in_compat_syscall())
3828 return copy_siginfo_from_user32(
3829 kinfo, (struct compat_siginfo __user *)info);
3831 return copy_siginfo_from_user(kinfo, info);
3834 static struct pid *pidfd_to_pid(const struct file *file)
3838 pid = pidfd_pid(file);
3842 return tgid_pidfd_to_pid(file);
3846 * sys_pidfd_send_signal - Signal a process through a pidfd
3847 * @pidfd: file descriptor of the process
3848 * @sig: signal to send
3849 * @info: signal info
3850 * @flags: future flags
3852 * The syscall currently only signals via PIDTYPE_PID which covers
3853 * kill(<positive-pid>, <signal>. It does not signal threads or process
3855 * In order to extend the syscall to threads and process groups the @flags
3856 * argument should be used. In essence, the @flags argument will determine
3857 * what is signaled and not the file descriptor itself. Put in other words,
3858 * grouping is a property of the flags argument not a property of the file
3861 * Return: 0 on success, negative errno on failure
3863 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3864 siginfo_t __user *, info, unsigned int, flags)
3869 kernel_siginfo_t kinfo;
3871 /* Enforce flags be set to 0 until we add an extension. */
3879 /* Is this a pidfd? */
3880 pid = pidfd_to_pid(f.file);
3887 if (!access_pidfd_pidns(pid))
3891 ret = copy_siginfo_from_user_any(&kinfo, info);
3896 if (unlikely(sig != kinfo.si_signo))
3899 /* Only allow sending arbitrary signals to yourself. */
3901 if ((task_pid(current) != pid) &&
3902 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3905 prepare_kill_siginfo(sig, &kinfo);
3908 ret = kill_pid_info(sig, &kinfo, pid);
3916 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3918 struct task_struct *p;
3922 p = find_task_by_vpid(pid);
3923 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3924 error = check_kill_permission(sig, info, p);
3926 * The null signal is a permissions and process existence
3927 * probe. No signal is actually delivered.
3929 if (!error && sig) {
3930 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3932 * If lock_task_sighand() failed we pretend the task
3933 * dies after receiving the signal. The window is tiny,
3934 * and the signal is private anyway.
3936 if (unlikely(error == -ESRCH))
3945 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3947 struct kernel_siginfo info;
3949 clear_siginfo(&info);
3950 info.si_signo = sig;
3952 info.si_code = SI_TKILL;
3953 info.si_pid = task_tgid_vnr(current);
3954 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3956 return do_send_specific(tgid, pid, sig, &info);
3960 * sys_tgkill - send signal to one specific thread
3961 * @tgid: the thread group ID of the thread
3962 * @pid: the PID of the thread
3963 * @sig: signal to be sent
3965 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3966 * exists but it's not belonging to the target process anymore. This
3967 * method solves the problem of threads exiting and PIDs getting reused.
3969 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3971 /* This is only valid for single tasks */
3972 if (pid <= 0 || tgid <= 0)
3975 return do_tkill(tgid, pid, sig);
3979 * sys_tkill - send signal to one specific task
3980 * @pid: the PID of the task
3981 * @sig: signal to be sent
3983 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3985 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3987 /* This is only valid for single tasks */
3991 return do_tkill(0, pid, sig);
3994 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3996 /* Not even root can pretend to send signals from the kernel.
3997 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3999 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4000 (task_pid_vnr(current) != pid))
4003 /* POSIX.1b doesn't mention process groups. */
4004 return kill_proc_info(sig, info, pid);
4008 * sys_rt_sigqueueinfo - send signal information to a signal
4009 * @pid: the PID of the thread
4010 * @sig: signal to be sent
4011 * @uinfo: signal info to be sent
4013 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
4014 siginfo_t __user *, uinfo)
4016 kernel_siginfo_t info;
4017 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4020 return do_rt_sigqueueinfo(pid, sig, &info);
4023 #ifdef CONFIG_COMPAT
4024 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
4027 struct compat_siginfo __user *, uinfo)
4029 kernel_siginfo_t info;
4030 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4033 return do_rt_sigqueueinfo(pid, sig, &info);
4037 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
4039 /* This is only valid for single tasks */
4040 if (pid <= 0 || tgid <= 0)
4043 /* Not even root can pretend to send signals from the kernel.
4044 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4046 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4047 (task_pid_vnr(current) != pid))
4050 return do_send_specific(tgid, pid, sig, info);
4053 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
4054 siginfo_t __user *, uinfo)
4056 kernel_siginfo_t info;
4057 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4060 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4063 #ifdef CONFIG_COMPAT
4064 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
4068 struct compat_siginfo __user *, uinfo)
4070 kernel_siginfo_t info;
4071 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4074 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4079 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
4081 void kernel_sigaction(int sig, __sighandler_t action)
4083 spin_lock_irq(¤t->sighand->siglock);
4084 current->sighand->action[sig - 1].sa.sa_handler = action;
4085 if (action == SIG_IGN) {
4089 sigaddset(&mask, sig);
4091 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
4092 flush_sigqueue_mask(&mask, ¤t->pending);
4093 recalc_sigpending();
4095 spin_unlock_irq(¤t->sighand->siglock);
4097 EXPORT_SYMBOL(kernel_sigaction);
4099 void __weak sigaction_compat_abi(struct k_sigaction *act,
4100 struct k_sigaction *oact)
4104 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
4106 struct task_struct *p = current, *t;
4107 struct k_sigaction *k;
4110 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
4113 k = &p->sighand->action[sig-1];
4115 spin_lock_irq(&p->sighand->siglock);
4116 if (k->sa.sa_flags & SA_IMMUTABLE) {
4117 spin_unlock_irq(&p->sighand->siglock);
4124 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
4125 * e.g. by having an architecture use the bit in their uapi.
4127 BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
4130 * Clear unknown flag bits in order to allow userspace to detect missing
4131 * support for flag bits and to allow the kernel to use non-uapi bits
4135 act->sa.sa_flags &= UAPI_SA_FLAGS;
4137 oact->sa.sa_flags &= UAPI_SA_FLAGS;
4139 sigaction_compat_abi(act, oact);
4142 sigdelsetmask(&act->sa.sa_mask,
4143 sigmask(SIGKILL) | sigmask(SIGSTOP));
4147 * "Setting a signal action to SIG_IGN for a signal that is
4148 * pending shall cause the pending signal to be discarded,
4149 * whether or not it is blocked."
4151 * "Setting a signal action to SIG_DFL for a signal that is
4152 * pending and whose default action is to ignore the signal
4153 * (for example, SIGCHLD), shall cause the pending signal to
4154 * be discarded, whether or not it is blocked"
4156 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
4158 sigaddset(&mask, sig);
4159 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
4160 for_each_thread(p, t)
4161 flush_sigqueue_mask(&mask, &t->pending);
4165 spin_unlock_irq(&p->sighand->siglock);
4169 #ifdef CONFIG_DYNAMIC_SIGFRAME
4170 static inline void sigaltstack_lock(void)
4171 __acquires(¤t->sighand->siglock)
4173 spin_lock_irq(¤t->sighand->siglock);
4176 static inline void sigaltstack_unlock(void)
4177 __releases(¤t->sighand->siglock)
4179 spin_unlock_irq(¤t->sighand->siglock);
4182 static inline void sigaltstack_lock(void) { }
4183 static inline void sigaltstack_unlock(void) { }
4187 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4190 struct task_struct *t = current;
4194 memset(oss, 0, sizeof(stack_t));
4195 oss->ss_sp = (void __user *) t->sas_ss_sp;
4196 oss->ss_size = t->sas_ss_size;
4197 oss->ss_flags = sas_ss_flags(sp) |
4198 (current->sas_ss_flags & SS_FLAG_BITS);
4202 void __user *ss_sp = ss->ss_sp;
4203 size_t ss_size = ss->ss_size;
4204 unsigned ss_flags = ss->ss_flags;
4207 if (unlikely(on_sig_stack(sp)))
4210 ss_mode = ss_flags & ~SS_FLAG_BITS;
4211 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4216 * Return before taking any locks if no actual
4217 * sigaltstack changes were requested.
4219 if (t->sas_ss_sp == (unsigned long)ss_sp &&
4220 t->sas_ss_size == ss_size &&
4221 t->sas_ss_flags == ss_flags)
4225 if (ss_mode == SS_DISABLE) {
4229 if (unlikely(ss_size < min_ss_size))
4231 if (!sigaltstack_size_valid(ss_size))
4235 t->sas_ss_sp = (unsigned long) ss_sp;
4236 t->sas_ss_size = ss_size;
4237 t->sas_ss_flags = ss_flags;
4239 sigaltstack_unlock();
4244 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4248 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4250 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4251 current_user_stack_pointer(),
4253 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4258 int restore_altstack(const stack_t __user *uss)
4261 if (copy_from_user(&new, uss, sizeof(stack_t)))
4263 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4265 /* squash all but EFAULT for now */
4269 int __save_altstack(stack_t __user *uss, unsigned long sp)
4271 struct task_struct *t = current;
4272 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4273 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4274 __put_user(t->sas_ss_size, &uss->ss_size);
4278 #ifdef CONFIG_COMPAT
4279 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4280 compat_stack_t __user *uoss_ptr)
4286 compat_stack_t uss32;
4287 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4289 uss.ss_sp = compat_ptr(uss32.ss_sp);
4290 uss.ss_flags = uss32.ss_flags;
4291 uss.ss_size = uss32.ss_size;
4293 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4294 compat_user_stack_pointer(),
4295 COMPAT_MINSIGSTKSZ);
4296 if (ret >= 0 && uoss_ptr) {
4298 memset(&old, 0, sizeof(old));
4299 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4300 old.ss_flags = uoss.ss_flags;
4301 old.ss_size = uoss.ss_size;
4302 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4308 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4309 const compat_stack_t __user *, uss_ptr,
4310 compat_stack_t __user *, uoss_ptr)
4312 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4315 int compat_restore_altstack(const compat_stack_t __user *uss)
4317 int err = do_compat_sigaltstack(uss, NULL);
4318 /* squash all but -EFAULT for now */
4319 return err == -EFAULT ? err : 0;
4322 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4325 struct task_struct *t = current;
4326 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4328 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4329 __put_user(t->sas_ss_size, &uss->ss_size);
4334 #ifdef __ARCH_WANT_SYS_SIGPENDING
4337 * sys_sigpending - examine pending signals
4338 * @uset: where mask of pending signal is returned
4340 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4344 if (sizeof(old_sigset_t) > sizeof(*uset))
4347 do_sigpending(&set);
4349 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4355 #ifdef CONFIG_COMPAT
4356 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4360 do_sigpending(&set);
4362 return put_user(set.sig[0], set32);
4368 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4370 * sys_sigprocmask - examine and change blocked signals
4371 * @how: whether to add, remove, or set signals
4372 * @nset: signals to add or remove (if non-null)
4373 * @oset: previous value of signal mask if non-null
4375 * Some platforms have their own version with special arguments;
4376 * others support only sys_rt_sigprocmask.
4379 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4380 old_sigset_t __user *, oset)
4382 old_sigset_t old_set, new_set;
4383 sigset_t new_blocked;
4385 old_set = current->blocked.sig[0];
4388 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4391 new_blocked = current->blocked;
4395 sigaddsetmask(&new_blocked, new_set);
4398 sigdelsetmask(&new_blocked, new_set);
4401 new_blocked.sig[0] = new_set;
4407 set_current_blocked(&new_blocked);
4411 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4417 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4419 #ifndef CONFIG_ODD_RT_SIGACTION
4421 * sys_rt_sigaction - alter an action taken by a process
4422 * @sig: signal to be sent
4423 * @act: new sigaction
4424 * @oact: used to save the previous sigaction
4425 * @sigsetsize: size of sigset_t type
4427 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4428 const struct sigaction __user *, act,
4429 struct sigaction __user *, oact,
4432 struct k_sigaction new_sa, old_sa;
4435 /* XXX: Don't preclude handling different sized sigset_t's. */
4436 if (sigsetsize != sizeof(sigset_t))
4439 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4442 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4446 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4451 #ifdef CONFIG_COMPAT
4452 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4453 const struct compat_sigaction __user *, act,
4454 struct compat_sigaction __user *, oact,
4455 compat_size_t, sigsetsize)
4457 struct k_sigaction new_ka, old_ka;
4458 #ifdef __ARCH_HAS_SA_RESTORER
4459 compat_uptr_t restorer;
4463 /* XXX: Don't preclude handling different sized sigset_t's. */
4464 if (sigsetsize != sizeof(compat_sigset_t))
4468 compat_uptr_t handler;
4469 ret = get_user(handler, &act->sa_handler);
4470 new_ka.sa.sa_handler = compat_ptr(handler);
4471 #ifdef __ARCH_HAS_SA_RESTORER
4472 ret |= get_user(restorer, &act->sa_restorer);
4473 new_ka.sa.sa_restorer = compat_ptr(restorer);
4475 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4476 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4481 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4483 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4485 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4486 sizeof(oact->sa_mask));
4487 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4488 #ifdef __ARCH_HAS_SA_RESTORER
4489 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4490 &oact->sa_restorer);
4496 #endif /* !CONFIG_ODD_RT_SIGACTION */
4498 #ifdef CONFIG_OLD_SIGACTION
4499 SYSCALL_DEFINE3(sigaction, int, sig,
4500 const struct old_sigaction __user *, act,
4501 struct old_sigaction __user *, oact)
4503 struct k_sigaction new_ka, old_ka;
4508 if (!access_ok(act, sizeof(*act)) ||
4509 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4510 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4511 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4512 __get_user(mask, &act->sa_mask))
4514 #ifdef __ARCH_HAS_KA_RESTORER
4515 new_ka.ka_restorer = NULL;
4517 siginitset(&new_ka.sa.sa_mask, mask);
4520 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4523 if (!access_ok(oact, sizeof(*oact)) ||
4524 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4525 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4526 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4527 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4534 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4535 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4536 const struct compat_old_sigaction __user *, act,
4537 struct compat_old_sigaction __user *, oact)
4539 struct k_sigaction new_ka, old_ka;
4541 compat_old_sigset_t mask;
4542 compat_uptr_t handler, restorer;
4545 if (!access_ok(act, sizeof(*act)) ||
4546 __get_user(handler, &act->sa_handler) ||
4547 __get_user(restorer, &act->sa_restorer) ||
4548 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4549 __get_user(mask, &act->sa_mask))
4552 #ifdef __ARCH_HAS_KA_RESTORER
4553 new_ka.ka_restorer = NULL;
4555 new_ka.sa.sa_handler = compat_ptr(handler);
4556 new_ka.sa.sa_restorer = compat_ptr(restorer);
4557 siginitset(&new_ka.sa.sa_mask, mask);
4560 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4563 if (!access_ok(oact, sizeof(*oact)) ||
4564 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4565 &oact->sa_handler) ||
4566 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4567 &oact->sa_restorer) ||
4568 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4569 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4576 #ifdef CONFIG_SGETMASK_SYSCALL
4579 * For backwards compatibility. Functionality superseded by sigprocmask.
4581 SYSCALL_DEFINE0(sgetmask)
4584 return current->blocked.sig[0];
4587 SYSCALL_DEFINE1(ssetmask, int, newmask)
4589 int old = current->blocked.sig[0];
4592 siginitset(&newset, newmask);
4593 set_current_blocked(&newset);
4597 #endif /* CONFIG_SGETMASK_SYSCALL */
4599 #ifdef __ARCH_WANT_SYS_SIGNAL
4601 * For backwards compatibility. Functionality superseded by sigaction.
4603 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4605 struct k_sigaction new_sa, old_sa;
4608 new_sa.sa.sa_handler = handler;
4609 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4610 sigemptyset(&new_sa.sa.sa_mask);
4612 ret = do_sigaction(sig, &new_sa, &old_sa);
4614 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4616 #endif /* __ARCH_WANT_SYS_SIGNAL */
4618 #ifdef __ARCH_WANT_SYS_PAUSE
4620 SYSCALL_DEFINE0(pause)
4622 while (!signal_pending(current)) {
4623 __set_current_state(TASK_INTERRUPTIBLE);
4626 return -ERESTARTNOHAND;
4631 static int sigsuspend(sigset_t *set)
4633 current->saved_sigmask = current->blocked;
4634 set_current_blocked(set);
4636 while (!signal_pending(current)) {
4637 __set_current_state(TASK_INTERRUPTIBLE);
4640 set_restore_sigmask();
4641 return -ERESTARTNOHAND;
4645 * sys_rt_sigsuspend - replace the signal mask for a value with the
4646 * @unewset value until a signal is received
4647 * @unewset: new signal mask value
4648 * @sigsetsize: size of sigset_t type
4650 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4654 /* XXX: Don't preclude handling different sized sigset_t's. */
4655 if (sigsetsize != sizeof(sigset_t))
4658 if (copy_from_user(&newset, unewset, sizeof(newset)))
4660 return sigsuspend(&newset);
4663 #ifdef CONFIG_COMPAT
4664 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4668 /* XXX: Don't preclude handling different sized sigset_t's. */
4669 if (sigsetsize != sizeof(sigset_t))
4672 if (get_compat_sigset(&newset, unewset))
4674 return sigsuspend(&newset);
4678 #ifdef CONFIG_OLD_SIGSUSPEND
4679 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4682 siginitset(&blocked, mask);
4683 return sigsuspend(&blocked);
4686 #ifdef CONFIG_OLD_SIGSUSPEND3
4687 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4690 siginitset(&blocked, mask);
4691 return sigsuspend(&blocked);
4695 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4700 static inline void siginfo_buildtime_checks(void)
4702 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4704 /* Verify the offsets in the two siginfos match */
4705 #define CHECK_OFFSET(field) \
4706 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4709 CHECK_OFFSET(si_pid);
4710 CHECK_OFFSET(si_uid);
4713 CHECK_OFFSET(si_tid);
4714 CHECK_OFFSET(si_overrun);
4715 CHECK_OFFSET(si_value);
4718 CHECK_OFFSET(si_pid);
4719 CHECK_OFFSET(si_uid);
4720 CHECK_OFFSET(si_value);
4723 CHECK_OFFSET(si_pid);
4724 CHECK_OFFSET(si_uid);
4725 CHECK_OFFSET(si_status);
4726 CHECK_OFFSET(si_utime);
4727 CHECK_OFFSET(si_stime);
4730 CHECK_OFFSET(si_addr);
4731 CHECK_OFFSET(si_trapno);
4732 CHECK_OFFSET(si_addr_lsb);
4733 CHECK_OFFSET(si_lower);
4734 CHECK_OFFSET(si_upper);
4735 CHECK_OFFSET(si_pkey);
4736 CHECK_OFFSET(si_perf_data);
4737 CHECK_OFFSET(si_perf_type);
4738 CHECK_OFFSET(si_perf_flags);
4741 CHECK_OFFSET(si_band);
4742 CHECK_OFFSET(si_fd);
4745 CHECK_OFFSET(si_call_addr);
4746 CHECK_OFFSET(si_syscall);
4747 CHECK_OFFSET(si_arch);
4751 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4752 offsetof(struct siginfo, si_addr));
4753 if (sizeof(int) == sizeof(void __user *)) {
4754 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4755 sizeof(void __user *));
4757 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4758 sizeof_field(struct siginfo, si_uid)) !=
4759 sizeof(void __user *));
4760 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4761 offsetof(struct siginfo, si_uid));
4763 #ifdef CONFIG_COMPAT
4764 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4765 offsetof(struct compat_siginfo, si_addr));
4766 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4767 sizeof(compat_uptr_t));
4768 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4769 sizeof_field(struct siginfo, si_pid));
4773 void __init signals_init(void)
4775 siginfo_buildtime_checks();
4777 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT);
4780 #ifdef CONFIG_KGDB_KDB
4781 #include <linux/kdb.h>
4783 * kdb_send_sig - Allows kdb to send signals without exposing
4784 * signal internals. This function checks if the required locks are
4785 * available before calling the main signal code, to avoid kdb
4788 void kdb_send_sig(struct task_struct *t, int sig)
4790 static struct task_struct *kdb_prev_t;
4792 if (!spin_trylock(&t->sighand->siglock)) {
4793 kdb_printf("Can't do kill command now.\n"
4794 "The sigmask lock is held somewhere else in "
4795 "kernel, try again later\n");
4798 new_t = kdb_prev_t != t;
4800 if (!task_is_running(t) && new_t) {
4801 spin_unlock(&t->sighand->siglock);
4802 kdb_printf("Process is not RUNNING, sending a signal from "
4803 "kdb risks deadlock\n"
4804 "on the run queue locks. "
4805 "The signal has _not_ been sent.\n"
4806 "Reissue the kill command if you want to risk "
4810 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4811 spin_unlock(&t->sighand->siglock);
4813 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4816 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4818 #endif /* CONFIG_KGDB_KDB */