1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
9 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
10 * Changes to use preallocated sigqueue structures
11 * to allow signals to be sent reliably.
14 #include <linux/slab.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/debug.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/sched/cputime.h>
23 #include <linux/file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/tty.h>
27 #include <linux/binfmts.h>
28 #include <linux/coredump.h>
29 #include <linux/security.h>
30 #include <linux/syscalls.h>
31 #include <linux/ptrace.h>
32 #include <linux/signal.h>
33 #include <linux/signalfd.h>
34 #include <linux/ratelimit.h>
35 #include <linux/tracehook.h>
36 #include <linux/capability.h>
37 #include <linux/freezer.h>
38 #include <linux/pid_namespace.h>
39 #include <linux/nsproxy.h>
40 #include <linux/user_namespace.h>
41 #include <linux/uprobes.h>
42 #include <linux/compat.h>
43 #include <linux/cn_proc.h>
44 #include <linux/compiler.h>
45 #include <linux/posix-timers.h>
46 #include <linux/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, kernel_siginfo_t *info)
631 bool resched_timer = false;
634 /* We only dequeue private signals from ourselves, we don't let
635 * signalfd steal them
637 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
639 signr = __dequeue_signal(&tsk->signal->shared_pending,
640 mask, info, &resched_timer);
641 #ifdef CONFIG_POSIX_TIMERS
645 * itimers are process shared and we restart periodic
646 * itimers in the signal delivery path to prevent DoS
647 * attacks in the high resolution timer case. This is
648 * compliant with the old way of self-restarting
649 * itimers, as the SIGALRM is a legacy signal and only
650 * queued once. Changing the restart behaviour to
651 * restart the timer in the signal dequeue path is
652 * reducing the timer noise on heavy loaded !highres
655 if (unlikely(signr == SIGALRM)) {
656 struct hrtimer *tmr = &tsk->signal->real_timer;
658 if (!hrtimer_is_queued(tmr) &&
659 tsk->signal->it_real_incr != 0) {
660 hrtimer_forward(tmr, tmr->base->get_time(),
661 tsk->signal->it_real_incr);
662 hrtimer_restart(tmr);
672 if (unlikely(sig_kernel_stop(signr))) {
674 * Set a marker that we have dequeued a stop signal. Our
675 * caller might release the siglock and then the pending
676 * stop signal it is about to process is no longer in the
677 * pending bitmasks, but must still be cleared by a SIGCONT
678 * (and overruled by a SIGKILL). So those cases clear this
679 * shared flag after we've set it. Note that this flag may
680 * remain set after the signal we return is ignored or
681 * handled. That doesn't matter because its only purpose
682 * is to alert stop-signal processing code when another
683 * processor has come along and cleared the flag.
685 current->jobctl |= JOBCTL_STOP_DEQUEUED;
687 #ifdef CONFIG_POSIX_TIMERS
690 * Release the siglock to ensure proper locking order
691 * of timer locks outside of siglocks. Note, we leave
692 * irqs disabled here, since the posix-timers code is
693 * about to disable them again anyway.
695 spin_unlock(&tsk->sighand->siglock);
696 posixtimer_rearm(info);
697 spin_lock(&tsk->sighand->siglock);
699 /* Don't expose the si_sys_private value to userspace */
700 info->si_sys_private = 0;
705 EXPORT_SYMBOL_GPL(dequeue_signal);
707 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
709 struct task_struct *tsk = current;
710 struct sigpending *pending = &tsk->pending;
711 struct sigqueue *q, *sync = NULL;
714 * Might a synchronous signal be in the queue?
716 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
720 * Return the first synchronous signal in the queue.
722 list_for_each_entry(q, &pending->list, list) {
723 /* Synchronous signals have a positive si_code */
724 if ((q->info.si_code > SI_USER) &&
725 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
733 * Check if there is another siginfo for the same signal.
735 list_for_each_entry_continue(q, &pending->list, list) {
736 if (q->info.si_signo == sync->info.si_signo)
740 sigdelset(&pending->signal, sync->info.si_signo);
743 list_del_init(&sync->list);
744 copy_siginfo(info, &sync->info);
745 __sigqueue_free(sync);
746 return info->si_signo;
750 * Tell a process that it has a new active signal..
752 * NOTE! we rely on the previous spin_lock to
753 * lock interrupts for us! We can only be called with
754 * "siglock" held, and the local interrupt must
755 * have been disabled when that got acquired!
757 * No need to set need_resched since signal event passing
758 * goes through ->blocked
760 void signal_wake_up_state(struct task_struct *t, unsigned int state)
762 set_tsk_thread_flag(t, TIF_SIGPENDING);
764 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
765 * case. We don't check t->state here because there is a race with it
766 * executing another processor and just now entering stopped state.
767 * By using wake_up_state, we ensure the process will wake up and
768 * handle its death signal.
770 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
775 * Remove signals in mask from the pending set and queue.
776 * Returns 1 if any signals were found.
778 * All callers must be holding the siglock.
780 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
782 struct sigqueue *q, *n;
785 sigandsets(&m, mask, &s->signal);
786 if (sigisemptyset(&m))
789 sigandnsets(&s->signal, &s->signal, mask);
790 list_for_each_entry_safe(q, n, &s->list, list) {
791 if (sigismember(mask, q->info.si_signo)) {
792 list_del_init(&q->list);
798 static inline int is_si_special(const struct kernel_siginfo *info)
800 return info <= SEND_SIG_PRIV;
803 static inline bool si_fromuser(const struct kernel_siginfo *info)
805 return info == SEND_SIG_NOINFO ||
806 (!is_si_special(info) && SI_FROMUSER(info));
810 * called with RCU read lock from check_kill_permission()
812 static bool kill_ok_by_cred(struct task_struct *t)
814 const struct cred *cred = current_cred();
815 const struct cred *tcred = __task_cred(t);
817 return uid_eq(cred->euid, tcred->suid) ||
818 uid_eq(cred->euid, tcred->uid) ||
819 uid_eq(cred->uid, tcred->suid) ||
820 uid_eq(cred->uid, tcred->uid) ||
821 ns_capable(tcred->user_ns, CAP_KILL);
825 * Bad permissions for sending the signal
826 * - the caller must hold the RCU read lock
828 static int check_kill_permission(int sig, struct kernel_siginfo *info,
829 struct task_struct *t)
834 if (!valid_signal(sig))
837 if (!si_fromuser(info))
840 error = audit_signal_info(sig, t); /* Let audit system see the signal */
844 if (!same_thread_group(current, t) &&
845 !kill_ok_by_cred(t)) {
848 sid = task_session(t);
850 * We don't return the error if sid == NULL. The
851 * task was unhashed, the caller must notice this.
853 if (!sid || sid == task_session(current))
861 return security_task_kill(t, info, sig, NULL);
865 * ptrace_trap_notify - schedule trap to notify ptracer
866 * @t: tracee wanting to notify tracer
868 * This function schedules sticky ptrace trap which is cleared on the next
869 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
872 * If @t is running, STOP trap will be taken. If trapped for STOP and
873 * ptracer is listening for events, tracee is woken up so that it can
874 * re-trap for the new event. If trapped otherwise, STOP trap will be
875 * eventually taken without returning to userland after the existing traps
876 * are finished by PTRACE_CONT.
879 * Must be called with @task->sighand->siglock held.
881 static void ptrace_trap_notify(struct task_struct *t)
883 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
884 assert_spin_locked(&t->sighand->siglock);
886 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
887 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
891 * Handle magic process-wide effects of stop/continue signals. Unlike
892 * the signal actions, these happen immediately at signal-generation
893 * time regardless of blocking, ignoring, or handling. This does the
894 * actual continuing for SIGCONT, but not the actual stopping for stop
895 * signals. The process stop is done as a signal action for SIG_DFL.
897 * Returns true if the signal should be actually delivered, otherwise
898 * it should be dropped.
900 static bool prepare_signal(int sig, struct task_struct *p, bool force)
902 struct signal_struct *signal = p->signal;
903 struct task_struct *t;
906 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
907 if (!(signal->flags & SIGNAL_GROUP_EXIT))
908 return sig == SIGKILL;
910 * The process is in the middle of dying, nothing to do.
912 } else if (sig_kernel_stop(sig)) {
914 * This is a stop signal. Remove SIGCONT from all queues.
916 siginitset(&flush, sigmask(SIGCONT));
917 flush_sigqueue_mask(&flush, &signal->shared_pending);
918 for_each_thread(p, t)
919 flush_sigqueue_mask(&flush, &t->pending);
920 } else if (sig == SIGCONT) {
923 * Remove all stop signals from all queues, wake all threads.
925 siginitset(&flush, SIG_KERNEL_STOP_MASK);
926 flush_sigqueue_mask(&flush, &signal->shared_pending);
927 for_each_thread(p, t) {
928 flush_sigqueue_mask(&flush, &t->pending);
929 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
930 if (likely(!(t->ptrace & PT_SEIZED)))
931 wake_up_state(t, __TASK_STOPPED);
933 ptrace_trap_notify(t);
937 * Notify the parent with CLD_CONTINUED if we were stopped.
939 * If we were in the middle of a group stop, we pretend it
940 * was already finished, and then continued. Since SIGCHLD
941 * doesn't queue we report only CLD_STOPPED, as if the next
942 * CLD_CONTINUED was dropped.
945 if (signal->flags & SIGNAL_STOP_STOPPED)
946 why |= SIGNAL_CLD_CONTINUED;
947 else if (signal->group_stop_count)
948 why |= SIGNAL_CLD_STOPPED;
952 * The first thread which returns from do_signal_stop()
953 * will take ->siglock, notice SIGNAL_CLD_MASK, and
954 * notify its parent. See get_signal().
956 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
957 signal->group_stop_count = 0;
958 signal->group_exit_code = 0;
962 return !sig_ignored(p, sig, force);
966 * Test if P wants to take SIG. After we've checked all threads with this,
967 * it's equivalent to finding no threads not blocking SIG. Any threads not
968 * blocking SIG were ruled out because they are not running and already
969 * have pending signals. Such threads will dequeue from the shared queue
970 * as soon as they're available, so putting the signal on the shared queue
971 * will be equivalent to sending it to one such thread.
973 static inline bool wants_signal(int sig, struct task_struct *p)
975 if (sigismember(&p->blocked, sig))
978 if (p->flags & PF_EXITING)
984 if (task_is_stopped_or_traced(p))
987 return task_curr(p) || !task_sigpending(p);
990 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
992 struct signal_struct *signal = p->signal;
993 struct task_struct *t;
996 * Now find a thread we can wake up to take the signal off the queue.
998 * If the main thread wants the signal, it gets first crack.
999 * Probably the least surprising to the average bear.
1001 if (wants_signal(sig, p))
1003 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1005 * There is just one thread and it does not need to be woken.
1006 * It will dequeue unblocked signals before it runs again.
1011 * Otherwise try to find a suitable thread.
1013 t = signal->curr_target;
1014 while (!wants_signal(sig, t)) {
1016 if (t == signal->curr_target)
1018 * No thread needs to be woken.
1019 * Any eligible threads will see
1020 * the signal in the queue soon.
1024 signal->curr_target = t;
1028 * Found a killable thread. If the signal will be fatal,
1029 * then start taking the whole group down immediately.
1031 if (sig_fatal(p, sig) &&
1032 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1033 !sigismember(&t->real_blocked, sig) &&
1034 (sig == SIGKILL || !p->ptrace)) {
1036 * This signal will be fatal to the whole group.
1038 if (!sig_kernel_coredump(sig)) {
1040 * Start a group exit and wake everybody up.
1041 * This way we don't have other threads
1042 * running and doing things after a slower
1043 * thread has the fatal signal pending.
1045 signal->flags = SIGNAL_GROUP_EXIT;
1046 signal->group_exit_code = sig;
1047 signal->group_stop_count = 0;
1050 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1051 sigaddset(&t->pending.signal, SIGKILL);
1052 signal_wake_up(t, 1);
1053 } while_each_thread(p, t);
1059 * The signal is already in the shared-pending queue.
1060 * Tell the chosen thread to wake up and dequeue it.
1062 signal_wake_up(t, sig == SIGKILL);
1066 static inline bool legacy_queue(struct sigpending *signals, int sig)
1068 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1071 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1072 enum pid_type type, bool force)
1074 struct sigpending *pending;
1076 int override_rlimit;
1077 int ret = 0, result;
1079 assert_spin_locked(&t->sighand->siglock);
1081 result = TRACE_SIGNAL_IGNORED;
1082 if (!prepare_signal(sig, t, force))
1085 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1087 * Short-circuit ignored signals and support queuing
1088 * exactly one non-rt signal, so that we can get more
1089 * detailed information about the cause of the signal.
1091 result = TRACE_SIGNAL_ALREADY_PENDING;
1092 if (legacy_queue(pending, sig))
1095 result = TRACE_SIGNAL_DELIVERED;
1097 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1099 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1103 * Real-time signals must be queued if sent by sigqueue, or
1104 * some other real-time mechanism. It is implementation
1105 * defined whether kill() does so. We attempt to do so, on
1106 * the principle of least surprise, but since kill is not
1107 * allowed to fail with EAGAIN when low on memory we just
1108 * make sure at least one signal gets delivered and don't
1109 * pass on the info struct.
1112 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1114 override_rlimit = 0;
1116 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
1119 list_add_tail(&q->list, &pending->list);
1120 switch ((unsigned long) info) {
1121 case (unsigned long) SEND_SIG_NOINFO:
1122 clear_siginfo(&q->info);
1123 q->info.si_signo = sig;
1124 q->info.si_errno = 0;
1125 q->info.si_code = SI_USER;
1126 q->info.si_pid = task_tgid_nr_ns(current,
1127 task_active_pid_ns(t));
1130 from_kuid_munged(task_cred_xxx(t, user_ns),
1134 case (unsigned long) SEND_SIG_PRIV:
1135 clear_siginfo(&q->info);
1136 q->info.si_signo = sig;
1137 q->info.si_errno = 0;
1138 q->info.si_code = SI_KERNEL;
1143 copy_siginfo(&q->info, info);
1146 } else if (!is_si_special(info) &&
1147 sig >= SIGRTMIN && info->si_code != SI_USER) {
1149 * Queue overflow, abort. We may abort if the
1150 * signal was rt and sent by user using something
1151 * other than kill().
1153 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1158 * This is a silent loss of information. We still
1159 * send the signal, but the *info bits are lost.
1161 result = TRACE_SIGNAL_LOSE_INFO;
1165 signalfd_notify(t, sig);
1166 sigaddset(&pending->signal, sig);
1168 /* Let multiprocess signals appear after on-going forks */
1169 if (type > PIDTYPE_TGID) {
1170 struct multiprocess_signals *delayed;
1171 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1172 sigset_t *signal = &delayed->signal;
1173 /* Can't queue both a stop and a continue signal */
1175 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1176 else if (sig_kernel_stop(sig))
1177 sigdelset(signal, SIGCONT);
1178 sigaddset(signal, sig);
1182 complete_signal(sig, t, type);
1184 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1188 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1191 switch (siginfo_layout(info->si_signo, info->si_code)) {
1200 case SIL_FAULT_TRAPNO:
1201 case SIL_FAULT_MCEERR:
1202 case SIL_FAULT_BNDERR:
1203 case SIL_FAULT_PKUERR:
1204 case SIL_FAULT_PERF_EVENT:
1212 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1215 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1218 if (info == SEND_SIG_NOINFO) {
1219 /* Force if sent from an ancestor pid namespace */
1220 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1221 } else if (info == SEND_SIG_PRIV) {
1222 /* Don't ignore kernel generated signals */
1224 } else if (has_si_pid_and_uid(info)) {
1225 /* SIGKILL and SIGSTOP is special or has ids */
1226 struct user_namespace *t_user_ns;
1229 t_user_ns = task_cred_xxx(t, user_ns);
1230 if (current_user_ns() != t_user_ns) {
1231 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1232 info->si_uid = from_kuid_munged(t_user_ns, uid);
1236 /* A kernel generated signal? */
1237 force = (info->si_code == SI_KERNEL);
1239 /* From an ancestor pid namespace? */
1240 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1245 return __send_signal(sig, info, t, type, force);
1248 static void print_fatal_signal(int signr)
1250 struct pt_regs *regs = signal_pt_regs();
1251 pr_info("potentially unexpected fatal signal %d.\n", signr);
1253 #if defined(__i386__) && !defined(__arch_um__)
1254 pr_info("code at %08lx: ", regs->ip);
1257 for (i = 0; i < 16; i++) {
1260 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1262 pr_cont("%02x ", insn);
1272 static int __init setup_print_fatal_signals(char *str)
1274 get_option (&str, &print_fatal_signals);
1279 __setup("print-fatal-signals=", setup_print_fatal_signals);
1282 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1284 return send_signal(sig, info, p, PIDTYPE_TGID);
1287 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1290 unsigned long flags;
1293 if (lock_task_sighand(p, &flags)) {
1294 ret = send_signal(sig, info, p, type);
1295 unlock_task_sighand(p, &flags);
1302 HANDLER_CURRENT, /* If reachable use the current handler */
1303 HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */
1304 HANDLER_EXIT, /* Only visible as the process exit code */
1308 * Force a signal that the process can't ignore: if necessary
1309 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1311 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1312 * since we do not want to have a signal handler that was blocked
1313 * be invoked when user space had explicitly blocked it.
1315 * We don't want to have recursive SIGSEGV's etc, for example,
1316 * that is why we also clear SIGNAL_UNKILLABLE.
1319 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
1320 enum sig_handler handler)
1322 unsigned long int flags;
1323 int ret, blocked, ignored;
1324 struct k_sigaction *action;
1325 int sig = info->si_signo;
1327 spin_lock_irqsave(&t->sighand->siglock, flags);
1328 action = &t->sighand->action[sig-1];
1329 ignored = action->sa.sa_handler == SIG_IGN;
1330 blocked = sigismember(&t->blocked, sig);
1331 if (blocked || ignored || (handler != HANDLER_CURRENT)) {
1332 action->sa.sa_handler = SIG_DFL;
1333 if (handler == HANDLER_EXIT)
1334 action->sa.sa_flags |= SA_IMMUTABLE;
1336 sigdelset(&t->blocked, sig);
1337 recalc_sigpending_and_wake(t);
1341 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1342 * debugging to leave init killable. But HANDLER_EXIT is always fatal.
1344 if (action->sa.sa_handler == SIG_DFL &&
1345 (!t->ptrace || (handler == HANDLER_EXIT)))
1346 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1347 ret = send_signal(sig, info, t, PIDTYPE_PID);
1348 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1353 int force_sig_info(struct kernel_siginfo *info)
1355 return force_sig_info_to_task(info, current, HANDLER_CURRENT);
1359 * Nuke all other threads in the group.
1361 int zap_other_threads(struct task_struct *p)
1363 struct task_struct *t = p;
1366 p->signal->group_stop_count = 0;
1368 while_each_thread(p, t) {
1369 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1372 /* Don't bother with already dead threads */
1375 sigaddset(&t->pending.signal, SIGKILL);
1376 signal_wake_up(t, 1);
1382 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1383 unsigned long *flags)
1385 struct sighand_struct *sighand;
1389 sighand = rcu_dereference(tsk->sighand);
1390 if (unlikely(sighand == NULL))
1394 * This sighand can be already freed and even reused, but
1395 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1396 * initializes ->siglock: this slab can't go away, it has
1397 * the same object type, ->siglock can't be reinitialized.
1399 * We need to ensure that tsk->sighand is still the same
1400 * after we take the lock, we can race with de_thread() or
1401 * __exit_signal(). In the latter case the next iteration
1402 * must see ->sighand == NULL.
1404 spin_lock_irqsave(&sighand->siglock, *flags);
1405 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1407 spin_unlock_irqrestore(&sighand->siglock, *flags);
1414 #ifdef CONFIG_LOCKDEP
1415 void lockdep_assert_task_sighand_held(struct task_struct *task)
1417 struct sighand_struct *sighand;
1420 sighand = rcu_dereference(task->sighand);
1422 lockdep_assert_held(&sighand->siglock);
1430 * send signal info to all the members of a group
1432 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1433 struct task_struct *p, enum pid_type type)
1438 ret = check_kill_permission(sig, info, p);
1442 ret = do_send_sig_info(sig, info, p, type);
1448 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1449 * control characters do (^C, ^Z etc)
1450 * - the caller must hold at least a readlock on tasklist_lock
1452 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1454 struct task_struct *p = NULL;
1455 int retval, success;
1459 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1460 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1463 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1464 return success ? 0 : retval;
1467 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1470 struct task_struct *p;
1474 p = pid_task(pid, PIDTYPE_PID);
1476 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1478 if (likely(!p || error != -ESRCH))
1482 * The task was unhashed in between, try again. If it
1483 * is dead, pid_task() will return NULL, if we race with
1484 * de_thread() it will find the new leader.
1489 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1493 error = kill_pid_info(sig, info, find_vpid(pid));
1498 static inline bool kill_as_cred_perm(const struct cred *cred,
1499 struct task_struct *target)
1501 const struct cred *pcred = __task_cred(target);
1503 return uid_eq(cred->euid, pcred->suid) ||
1504 uid_eq(cred->euid, pcred->uid) ||
1505 uid_eq(cred->uid, pcred->suid) ||
1506 uid_eq(cred->uid, pcred->uid);
1510 * The usb asyncio usage of siginfo is wrong. The glibc support
1511 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1512 * AKA after the generic fields:
1513 * kernel_pid_t si_pid;
1514 * kernel_uid32_t si_uid;
1515 * sigval_t si_value;
1517 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1518 * after the generic fields is:
1519 * void __user *si_addr;
1521 * This is a practical problem when there is a 64bit big endian kernel
1522 * and a 32bit userspace. As the 32bit address will encoded in the low
1523 * 32bits of the pointer. Those low 32bits will be stored at higher
1524 * address than appear in a 32 bit pointer. So userspace will not
1525 * see the address it was expecting for it's completions.
1527 * There is nothing in the encoding that can allow
1528 * copy_siginfo_to_user32 to detect this confusion of formats, so
1529 * handle this by requiring the caller of kill_pid_usb_asyncio to
1530 * notice when this situration takes place and to store the 32bit
1531 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1534 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1535 struct pid *pid, const struct cred *cred)
1537 struct kernel_siginfo info;
1538 struct task_struct *p;
1539 unsigned long flags;
1542 if (!valid_signal(sig))
1545 clear_siginfo(&info);
1546 info.si_signo = sig;
1547 info.si_errno = errno;
1548 info.si_code = SI_ASYNCIO;
1549 *((sigval_t *)&info.si_pid) = addr;
1552 p = pid_task(pid, PIDTYPE_PID);
1557 if (!kill_as_cred_perm(cred, p)) {
1561 ret = security_task_kill(p, &info, sig, cred);
1566 if (lock_task_sighand(p, &flags)) {
1567 ret = __send_signal(sig, &info, p, PIDTYPE_TGID, false);
1568 unlock_task_sighand(p, &flags);
1576 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1579 * kill_something_info() interprets pid in interesting ways just like kill(2).
1581 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1582 * is probably wrong. Should make it like BSD or SYSV.
1585 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1590 return kill_proc_info(sig, info, pid);
1592 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1596 read_lock(&tasklist_lock);
1598 ret = __kill_pgrp_info(sig, info,
1599 pid ? find_vpid(-pid) : task_pgrp(current));
1601 int retval = 0, count = 0;
1602 struct task_struct * p;
1604 for_each_process(p) {
1605 if (task_pid_vnr(p) > 1 &&
1606 !same_thread_group(p, current)) {
1607 int err = group_send_sig_info(sig, info, p,
1614 ret = count ? retval : -ESRCH;
1616 read_unlock(&tasklist_lock);
1622 * These are for backward compatibility with the rest of the kernel source.
1625 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1628 * Make sure legacy kernel users don't send in bad values
1629 * (normal paths check this in check_kill_permission).
1631 if (!valid_signal(sig))
1634 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1636 EXPORT_SYMBOL(send_sig_info);
1638 #define __si_special(priv) \
1639 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1642 send_sig(int sig, struct task_struct *p, int priv)
1644 return send_sig_info(sig, __si_special(priv), p);
1646 EXPORT_SYMBOL(send_sig);
1648 void force_sig(int sig)
1650 struct kernel_siginfo info;
1652 clear_siginfo(&info);
1653 info.si_signo = sig;
1655 info.si_code = SI_KERNEL;
1658 force_sig_info(&info);
1660 EXPORT_SYMBOL(force_sig);
1662 void force_fatal_sig(int sig)
1664 struct kernel_siginfo info;
1666 clear_siginfo(&info);
1667 info.si_signo = sig;
1669 info.si_code = SI_KERNEL;
1672 force_sig_info_to_task(&info, current, HANDLER_SIG_DFL);
1675 void force_exit_sig(int sig)
1677 struct kernel_siginfo info;
1679 clear_siginfo(&info);
1680 info.si_signo = sig;
1682 info.si_code = SI_KERNEL;
1685 force_sig_info_to_task(&info, current, HANDLER_EXIT);
1689 * When things go south during signal handling, we
1690 * will force a SIGSEGV. And if the signal that caused
1691 * the problem was already a SIGSEGV, we'll want to
1692 * make sure we don't even try to deliver the signal..
1694 void force_sigsegv(int sig)
1697 force_fatal_sig(SIGSEGV);
1702 int force_sig_fault_to_task(int sig, int code, void __user *addr
1703 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1704 , struct task_struct *t)
1706 struct kernel_siginfo info;
1708 clear_siginfo(&info);
1709 info.si_signo = sig;
1711 info.si_code = code;
1712 info.si_addr = addr;
1715 info.si_flags = flags;
1718 return force_sig_info_to_task(&info, t, HANDLER_CURRENT);
1721 int force_sig_fault(int sig, int code, void __user *addr
1722 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1724 return force_sig_fault_to_task(sig, code, addr
1725 ___ARCH_SI_IA64(imm, flags, isr), current);
1728 int send_sig_fault(int sig, int code, void __user *addr
1729 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1730 , struct task_struct *t)
1732 struct kernel_siginfo info;
1734 clear_siginfo(&info);
1735 info.si_signo = sig;
1737 info.si_code = code;
1738 info.si_addr = addr;
1741 info.si_flags = flags;
1744 return send_sig_info(info.si_signo, &info, t);
1747 int force_sig_mceerr(int code, void __user *addr, short lsb)
1749 struct kernel_siginfo info;
1751 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1752 clear_siginfo(&info);
1753 info.si_signo = SIGBUS;
1755 info.si_code = code;
1756 info.si_addr = addr;
1757 info.si_addr_lsb = lsb;
1758 return force_sig_info(&info);
1761 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1763 struct kernel_siginfo info;
1765 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1766 clear_siginfo(&info);
1767 info.si_signo = SIGBUS;
1769 info.si_code = code;
1770 info.si_addr = addr;
1771 info.si_addr_lsb = lsb;
1772 return send_sig_info(info.si_signo, &info, t);
1774 EXPORT_SYMBOL(send_sig_mceerr);
1776 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1778 struct kernel_siginfo info;
1780 clear_siginfo(&info);
1781 info.si_signo = SIGSEGV;
1783 info.si_code = SEGV_BNDERR;
1784 info.si_addr = addr;
1785 info.si_lower = lower;
1786 info.si_upper = upper;
1787 return force_sig_info(&info);
1791 int force_sig_pkuerr(void __user *addr, u32 pkey)
1793 struct kernel_siginfo info;
1795 clear_siginfo(&info);
1796 info.si_signo = SIGSEGV;
1798 info.si_code = SEGV_PKUERR;
1799 info.si_addr = addr;
1800 info.si_pkey = pkey;
1801 return force_sig_info(&info);
1805 int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
1807 struct kernel_siginfo info;
1809 clear_siginfo(&info);
1810 info.si_signo = SIGTRAP;
1812 info.si_code = TRAP_PERF;
1813 info.si_addr = addr;
1814 info.si_perf_data = sig_data;
1815 info.si_perf_type = type;
1818 * Signals generated by perf events should not terminate the whole
1819 * process if SIGTRAP is blocked, however, delivering the signal
1820 * asynchronously is better than not delivering at all. But tell user
1821 * space if the signal was asynchronous, so it can clearly be
1822 * distinguished from normal synchronous ones.
1824 info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ?
1825 TRAP_PERF_FLAG_ASYNC :
1828 return send_sig_info(info.si_signo, &info, current);
1832 * force_sig_seccomp - signals the task to allow in-process syscall emulation
1833 * @syscall: syscall number to send to userland
1834 * @reason: filter-supplied reason code to send to userland (via si_errno)
1836 * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
1838 int force_sig_seccomp(int syscall, int reason, bool force_coredump)
1840 struct kernel_siginfo info;
1842 clear_siginfo(&info);
1843 info.si_signo = SIGSYS;
1844 info.si_code = SYS_SECCOMP;
1845 info.si_call_addr = (void __user *)KSTK_EIP(current);
1846 info.si_errno = reason;
1847 info.si_arch = syscall_get_arch(current);
1848 info.si_syscall = syscall;
1849 return force_sig_info_to_task(&info, current,
1850 force_coredump ? HANDLER_EXIT : HANDLER_CURRENT);
1853 /* For the crazy architectures that include trap information in
1854 * the errno field, instead of an actual errno value.
1856 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1858 struct kernel_siginfo info;
1860 clear_siginfo(&info);
1861 info.si_signo = SIGTRAP;
1862 info.si_errno = errno;
1863 info.si_code = TRAP_HWBKPT;
1864 info.si_addr = addr;
1865 return force_sig_info(&info);
1868 /* For the rare architectures that include trap information using
1871 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
1873 struct kernel_siginfo info;
1875 clear_siginfo(&info);
1876 info.si_signo = sig;
1878 info.si_code = code;
1879 info.si_addr = addr;
1880 info.si_trapno = trapno;
1881 return force_sig_info(&info);
1884 /* For the rare architectures that include trap information using
1887 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
1888 struct task_struct *t)
1890 struct kernel_siginfo info;
1892 clear_siginfo(&info);
1893 info.si_signo = sig;
1895 info.si_code = code;
1896 info.si_addr = addr;
1897 info.si_trapno = trapno;
1898 return send_sig_info(info.si_signo, &info, t);
1901 int kill_pgrp(struct pid *pid, int sig, int priv)
1905 read_lock(&tasklist_lock);
1906 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1907 read_unlock(&tasklist_lock);
1911 EXPORT_SYMBOL(kill_pgrp);
1913 int kill_pid(struct pid *pid, int sig, int priv)
1915 return kill_pid_info(sig, __si_special(priv), pid);
1917 EXPORT_SYMBOL(kill_pid);
1920 * These functions support sending signals using preallocated sigqueue
1921 * structures. This is needed "because realtime applications cannot
1922 * afford to lose notifications of asynchronous events, like timer
1923 * expirations or I/O completions". In the case of POSIX Timers
1924 * we allocate the sigqueue structure from the timer_create. If this
1925 * allocation fails we are able to report the failure to the application
1926 * with an EAGAIN error.
1928 struct sigqueue *sigqueue_alloc(void)
1930 return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
1933 void sigqueue_free(struct sigqueue *q)
1935 unsigned long flags;
1936 spinlock_t *lock = ¤t->sighand->siglock;
1938 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1940 * We must hold ->siglock while testing q->list
1941 * to serialize with collect_signal() or with
1942 * __exit_signal()->flush_sigqueue().
1944 spin_lock_irqsave(lock, flags);
1945 q->flags &= ~SIGQUEUE_PREALLOC;
1947 * If it is queued it will be freed when dequeued,
1948 * like the "regular" sigqueue.
1950 if (!list_empty(&q->list))
1952 spin_unlock_irqrestore(lock, flags);
1958 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1960 int sig = q->info.si_signo;
1961 struct sigpending *pending;
1962 struct task_struct *t;
1963 unsigned long flags;
1966 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1970 t = pid_task(pid, type);
1971 if (!t || !likely(lock_task_sighand(t, &flags)))
1974 ret = 1; /* the signal is ignored */
1975 result = TRACE_SIGNAL_IGNORED;
1976 if (!prepare_signal(sig, t, false))
1980 if (unlikely(!list_empty(&q->list))) {
1982 * If an SI_TIMER entry is already queue just increment
1983 * the overrun count.
1985 BUG_ON(q->info.si_code != SI_TIMER);
1986 q->info.si_overrun++;
1987 result = TRACE_SIGNAL_ALREADY_PENDING;
1990 q->info.si_overrun = 0;
1992 signalfd_notify(t, sig);
1993 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1994 list_add_tail(&q->list, &pending->list);
1995 sigaddset(&pending->signal, sig);
1996 complete_signal(sig, t, type);
1997 result = TRACE_SIGNAL_DELIVERED;
1999 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
2000 unlock_task_sighand(t, &flags);
2006 static void do_notify_pidfd(struct task_struct *task)
2010 WARN_ON(task->exit_state == 0);
2011 pid = task_pid(task);
2012 wake_up_all(&pid->wait_pidfd);
2016 * Let a parent know about the death of a child.
2017 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
2019 * Returns true if our parent ignored us and so we've switched to
2022 bool do_notify_parent(struct task_struct *tsk, int sig)
2024 struct kernel_siginfo info;
2025 unsigned long flags;
2026 struct sighand_struct *psig;
2027 bool autoreap = false;
2030 WARN_ON_ONCE(sig == -1);
2032 /* do_notify_parent_cldstop should have been called instead. */
2033 WARN_ON_ONCE(task_is_stopped_or_traced(tsk));
2035 WARN_ON_ONCE(!tsk->ptrace &&
2036 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
2038 /* Wake up all pidfd waiters */
2039 do_notify_pidfd(tsk);
2041 if (sig != SIGCHLD) {
2043 * This is only possible if parent == real_parent.
2044 * Check if it has changed security domain.
2046 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
2050 clear_siginfo(&info);
2051 info.si_signo = sig;
2054 * We are under tasklist_lock here so our parent is tied to
2055 * us and cannot change.
2057 * task_active_pid_ns will always return the same pid namespace
2058 * until a task passes through release_task.
2060 * write_lock() currently calls preempt_disable() which is the
2061 * same as rcu_read_lock(), but according to Oleg, this is not
2062 * correct to rely on this
2065 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
2066 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
2070 task_cputime(tsk, &utime, &stime);
2071 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
2072 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
2074 info.si_status = tsk->exit_code & 0x7f;
2075 if (tsk->exit_code & 0x80)
2076 info.si_code = CLD_DUMPED;
2077 else if (tsk->exit_code & 0x7f)
2078 info.si_code = CLD_KILLED;
2080 info.si_code = CLD_EXITED;
2081 info.si_status = tsk->exit_code >> 8;
2084 psig = tsk->parent->sighand;
2085 spin_lock_irqsave(&psig->siglock, flags);
2086 if (!tsk->ptrace && sig == SIGCHLD &&
2087 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
2088 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
2090 * We are exiting and our parent doesn't care. POSIX.1
2091 * defines special semantics for setting SIGCHLD to SIG_IGN
2092 * or setting the SA_NOCLDWAIT flag: we should be reaped
2093 * automatically and not left for our parent's wait4 call.
2094 * Rather than having the parent do it as a magic kind of
2095 * signal handler, we just set this to tell do_exit that we
2096 * can be cleaned up without becoming a zombie. Note that
2097 * we still call __wake_up_parent in this case, because a
2098 * blocked sys_wait4 might now return -ECHILD.
2100 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
2101 * is implementation-defined: we do (if you don't want
2102 * it, just use SIG_IGN instead).
2105 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
2109 * Send with __send_signal as si_pid and si_uid are in the
2110 * parent's namespaces.
2112 if (valid_signal(sig) && sig)
2113 __send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false);
2114 __wake_up_parent(tsk, tsk->parent);
2115 spin_unlock_irqrestore(&psig->siglock, flags);
2121 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2122 * @tsk: task reporting the state change
2123 * @for_ptracer: the notification is for ptracer
2124 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2126 * Notify @tsk's parent that the stopped/continued state has changed. If
2127 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2128 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2131 * Must be called with tasklist_lock at least read locked.
2133 static void do_notify_parent_cldstop(struct task_struct *tsk,
2134 bool for_ptracer, int why)
2136 struct kernel_siginfo info;
2137 unsigned long flags;
2138 struct task_struct *parent;
2139 struct sighand_struct *sighand;
2143 parent = tsk->parent;
2145 tsk = tsk->group_leader;
2146 parent = tsk->real_parent;
2149 clear_siginfo(&info);
2150 info.si_signo = SIGCHLD;
2153 * see comment in do_notify_parent() about the following 4 lines
2156 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2157 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2160 task_cputime(tsk, &utime, &stime);
2161 info.si_utime = nsec_to_clock_t(utime);
2162 info.si_stime = nsec_to_clock_t(stime);
2167 info.si_status = SIGCONT;
2170 info.si_status = tsk->signal->group_exit_code & 0x7f;
2173 info.si_status = tsk->exit_code & 0x7f;
2179 sighand = parent->sighand;
2180 spin_lock_irqsave(&sighand->siglock, flags);
2181 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2182 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2183 __group_send_sig_info(SIGCHLD, &info, parent);
2185 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2187 __wake_up_parent(tsk, parent);
2188 spin_unlock_irqrestore(&sighand->siglock, flags);
2191 static inline bool may_ptrace_stop(void)
2193 if (!likely(current->ptrace))
2196 * Are we in the middle of do_coredump?
2197 * If so and our tracer is also part of the coredump stopping
2198 * is a deadlock situation, and pointless because our tracer
2199 * is dead so don't allow us to stop.
2200 * If SIGKILL was already sent before the caller unlocked
2201 * ->siglock we must see ->core_state != NULL. Otherwise it
2202 * is safe to enter schedule().
2204 * This is almost outdated, a task with the pending SIGKILL can't
2205 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2206 * after SIGKILL was already dequeued.
2208 if (unlikely(current->mm->core_state) &&
2209 unlikely(current->mm == current->parent->mm))
2217 * This must be called with current->sighand->siglock held.
2219 * This should be the path for all ptrace stops.
2220 * We always set current->last_siginfo while stopped here.
2221 * That makes it a way to test a stopped process for
2222 * being ptrace-stopped vs being job-control-stopped.
2224 * If we actually decide not to stop at all because the tracer
2225 * is gone, we keep current->exit_code unless clear_code.
2227 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2228 __releases(¤t->sighand->siglock)
2229 __acquires(¤t->sighand->siglock)
2231 bool gstop_done = false;
2233 if (arch_ptrace_stop_needed(exit_code, info)) {
2235 * The arch code has something special to do before a
2236 * ptrace stop. This is allowed to block, e.g. for faults
2237 * on user stack pages. We can't keep the siglock while
2238 * calling arch_ptrace_stop, so we must release it now.
2239 * To preserve proper semantics, we must do this before
2240 * any signal bookkeeping like checking group_stop_count.
2242 spin_unlock_irq(¤t->sighand->siglock);
2243 arch_ptrace_stop(exit_code, info);
2244 spin_lock_irq(¤t->sighand->siglock);
2248 * schedule() will not sleep if there is a pending signal that
2249 * can awaken the task.
2251 set_special_state(TASK_TRACED);
2254 * We're committing to trapping. TRACED should be visible before
2255 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2256 * Also, transition to TRACED and updates to ->jobctl should be
2257 * atomic with respect to siglock and should be done after the arch
2258 * hook as siglock is released and regrabbed across it.
2263 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2265 * set_current_state() smp_wmb();
2267 * wait_task_stopped()
2268 * task_stopped_code()
2269 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2273 current->last_siginfo = info;
2274 current->exit_code = exit_code;
2277 * If @why is CLD_STOPPED, we're trapping to participate in a group
2278 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2279 * across siglock relocks since INTERRUPT was scheduled, PENDING
2280 * could be clear now. We act as if SIGCONT is received after
2281 * TASK_TRACED is entered - ignore it.
2283 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2284 gstop_done = task_participate_group_stop(current);
2286 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2287 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2288 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2289 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2291 /* entering a trap, clear TRAPPING */
2292 task_clear_jobctl_trapping(current);
2294 spin_unlock_irq(¤t->sighand->siglock);
2295 read_lock(&tasklist_lock);
2296 if (may_ptrace_stop()) {
2298 * Notify parents of the stop.
2300 * While ptraced, there are two parents - the ptracer and
2301 * the real_parent of the group_leader. The ptracer should
2302 * know about every stop while the real parent is only
2303 * interested in the completion of group stop. The states
2304 * for the two don't interact with each other. Notify
2305 * separately unless they're gonna be duplicates.
2307 do_notify_parent_cldstop(current, true, why);
2308 if (gstop_done && ptrace_reparented(current))
2309 do_notify_parent_cldstop(current, false, why);
2312 * Don't want to allow preemption here, because
2313 * sys_ptrace() needs this task to be inactive.
2315 * XXX: implement read_unlock_no_resched().
2318 read_unlock(&tasklist_lock);
2319 cgroup_enter_frozen();
2320 preempt_enable_no_resched();
2321 freezable_schedule();
2322 cgroup_leave_frozen(true);
2325 * By the time we got the lock, our tracer went away.
2326 * Don't drop the lock yet, another tracer may come.
2328 * If @gstop_done, the ptracer went away between group stop
2329 * completion and here. During detach, it would have set
2330 * JOBCTL_STOP_PENDING on us and we'll re-enter
2331 * TASK_STOPPED in do_signal_stop() on return, so notifying
2332 * the real parent of the group stop completion is enough.
2335 do_notify_parent_cldstop(current, false, why);
2337 /* tasklist protects us from ptrace_freeze_traced() */
2338 __set_current_state(TASK_RUNNING);
2340 current->exit_code = 0;
2341 read_unlock(&tasklist_lock);
2345 * We are back. Now reacquire the siglock before touching
2346 * last_siginfo, so that we are sure to have synchronized with
2347 * any signal-sending on another CPU that wants to examine it.
2349 spin_lock_irq(¤t->sighand->siglock);
2350 current->last_siginfo = NULL;
2352 /* LISTENING can be set only during STOP traps, clear it */
2353 current->jobctl &= ~JOBCTL_LISTENING;
2356 * Queued signals ignored us while we were stopped for tracing.
2357 * So check for any that we should take before resuming user mode.
2358 * This sets TIF_SIGPENDING, but never clears it.
2360 recalc_sigpending_tsk(current);
2363 static void ptrace_do_notify(int signr, int exit_code, int why)
2365 kernel_siginfo_t info;
2367 clear_siginfo(&info);
2368 info.si_signo = signr;
2369 info.si_code = exit_code;
2370 info.si_pid = task_pid_vnr(current);
2371 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2373 /* Let the debugger run. */
2374 ptrace_stop(exit_code, why, 1, &info);
2377 void ptrace_notify(int exit_code)
2379 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2380 if (unlikely(current->task_works))
2383 spin_lock_irq(¤t->sighand->siglock);
2384 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2385 spin_unlock_irq(¤t->sighand->siglock);
2389 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2390 * @signr: signr causing group stop if initiating
2392 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2393 * and participate in it. If already set, participate in the existing
2394 * group stop. If participated in a group stop (and thus slept), %true is
2395 * returned with siglock released.
2397 * If ptraced, this function doesn't handle stop itself. Instead,
2398 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2399 * untouched. The caller must ensure that INTERRUPT trap handling takes
2400 * places afterwards.
2403 * Must be called with @current->sighand->siglock held, which is released
2407 * %false if group stop is already cancelled or ptrace trap is scheduled.
2408 * %true if participated in group stop.
2410 static bool do_signal_stop(int signr)
2411 __releases(¤t->sighand->siglock)
2413 struct signal_struct *sig = current->signal;
2415 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2416 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2417 struct task_struct *t;
2419 /* signr will be recorded in task->jobctl for retries */
2420 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2422 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2423 unlikely(signal_group_exit(sig)))
2426 * There is no group stop already in progress. We must
2429 * While ptraced, a task may be resumed while group stop is
2430 * still in effect and then receive a stop signal and
2431 * initiate another group stop. This deviates from the
2432 * usual behavior as two consecutive stop signals can't
2433 * cause two group stops when !ptraced. That is why we
2434 * also check !task_is_stopped(t) below.
2436 * The condition can be distinguished by testing whether
2437 * SIGNAL_STOP_STOPPED is already set. Don't generate
2438 * group_exit_code in such case.
2440 * This is not necessary for SIGNAL_STOP_CONTINUED because
2441 * an intervening stop signal is required to cause two
2442 * continued events regardless of ptrace.
2444 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2445 sig->group_exit_code = signr;
2447 sig->group_stop_count = 0;
2449 if (task_set_jobctl_pending(current, signr | gstop))
2450 sig->group_stop_count++;
2453 while_each_thread(current, t) {
2455 * Setting state to TASK_STOPPED for a group
2456 * stop is always done with the siglock held,
2457 * so this check has no races.
2459 if (!task_is_stopped(t) &&
2460 task_set_jobctl_pending(t, signr | gstop)) {
2461 sig->group_stop_count++;
2462 if (likely(!(t->ptrace & PT_SEIZED)))
2463 signal_wake_up(t, 0);
2465 ptrace_trap_notify(t);
2470 if (likely(!current->ptrace)) {
2474 * If there are no other threads in the group, or if there
2475 * is a group stop in progress and we are the last to stop,
2476 * report to the parent.
2478 if (task_participate_group_stop(current))
2479 notify = CLD_STOPPED;
2481 set_special_state(TASK_STOPPED);
2482 spin_unlock_irq(¤t->sighand->siglock);
2485 * Notify the parent of the group stop completion. Because
2486 * we're not holding either the siglock or tasklist_lock
2487 * here, ptracer may attach inbetween; however, this is for
2488 * group stop and should always be delivered to the real
2489 * parent of the group leader. The new ptracer will get
2490 * its notification when this task transitions into
2494 read_lock(&tasklist_lock);
2495 do_notify_parent_cldstop(current, false, notify);
2496 read_unlock(&tasklist_lock);
2499 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2500 cgroup_enter_frozen();
2501 freezable_schedule();
2505 * While ptraced, group stop is handled by STOP trap.
2506 * Schedule it and let the caller deal with it.
2508 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2514 * do_jobctl_trap - take care of ptrace jobctl traps
2516 * When PT_SEIZED, it's used for both group stop and explicit
2517 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2518 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2519 * the stop signal; otherwise, %SIGTRAP.
2521 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2522 * number as exit_code and no siginfo.
2525 * Must be called with @current->sighand->siglock held, which may be
2526 * released and re-acquired before returning with intervening sleep.
2528 static void do_jobctl_trap(void)
2530 struct signal_struct *signal = current->signal;
2531 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2533 if (current->ptrace & PT_SEIZED) {
2534 if (!signal->group_stop_count &&
2535 !(signal->flags & SIGNAL_STOP_STOPPED))
2537 WARN_ON_ONCE(!signr);
2538 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2541 WARN_ON_ONCE(!signr);
2542 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2543 current->exit_code = 0;
2548 * do_freezer_trap - handle the freezer jobctl trap
2550 * Puts the task into frozen state, if only the task is not about to quit.
2551 * In this case it drops JOBCTL_TRAP_FREEZE.
2554 * Must be called with @current->sighand->siglock held,
2555 * which is always released before returning.
2557 static void do_freezer_trap(void)
2558 __releases(¤t->sighand->siglock)
2561 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2562 * let's make another loop to give it a chance to be handled.
2563 * In any case, we'll return back.
2565 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2566 JOBCTL_TRAP_FREEZE) {
2567 spin_unlock_irq(¤t->sighand->siglock);
2572 * Now we're sure that there is no pending fatal signal and no
2573 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2574 * immediately (if there is a non-fatal signal pending), and
2575 * put the task into sleep.
2577 __set_current_state(TASK_INTERRUPTIBLE);
2578 clear_thread_flag(TIF_SIGPENDING);
2579 spin_unlock_irq(¤t->sighand->siglock);
2580 cgroup_enter_frozen();
2581 freezable_schedule();
2584 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2587 * We do not check sig_kernel_stop(signr) but set this marker
2588 * unconditionally because we do not know whether debugger will
2589 * change signr. This flag has no meaning unless we are going
2590 * to stop after return from ptrace_stop(). In this case it will
2591 * be checked in do_signal_stop(), we should only stop if it was
2592 * not cleared by SIGCONT while we were sleeping. See also the
2593 * comment in dequeue_signal().
2595 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2596 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2598 /* We're back. Did the debugger cancel the sig? */
2599 signr = current->exit_code;
2603 current->exit_code = 0;
2606 * Update the siginfo structure if the signal has
2607 * changed. If the debugger wanted something
2608 * specific in the siginfo structure then it should
2609 * have updated *info via PTRACE_SETSIGINFO.
2611 if (signr != info->si_signo) {
2612 clear_siginfo(info);
2613 info->si_signo = signr;
2615 info->si_code = SI_USER;
2617 info->si_pid = task_pid_vnr(current->parent);
2618 info->si_uid = from_kuid_munged(current_user_ns(),
2619 task_uid(current->parent));
2623 /* If the (new) signal is now blocked, requeue it. */
2624 if (sigismember(¤t->blocked, signr)) {
2625 send_signal(signr, info, current, PIDTYPE_PID);
2632 static void hide_si_addr_tag_bits(struct ksignal *ksig)
2634 switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
2636 case SIL_FAULT_TRAPNO:
2637 case SIL_FAULT_MCEERR:
2638 case SIL_FAULT_BNDERR:
2639 case SIL_FAULT_PKUERR:
2640 case SIL_FAULT_PERF_EVENT:
2641 ksig->info.si_addr = arch_untagged_si_addr(
2642 ksig->info.si_addr, ksig->sig, ksig->info.si_code);
2654 bool get_signal(struct ksignal *ksig)
2656 struct sighand_struct *sighand = current->sighand;
2657 struct signal_struct *signal = current->signal;
2660 if (unlikely(current->task_works))
2664 * For non-generic architectures, check for TIF_NOTIFY_SIGNAL so
2665 * that the arch handlers don't all have to do it. If we get here
2666 * without TIF_SIGPENDING, just exit after running signal work.
2668 if (!IS_ENABLED(CONFIG_GENERIC_ENTRY)) {
2669 if (test_thread_flag(TIF_NOTIFY_SIGNAL))
2670 tracehook_notify_signal();
2671 if (!task_sigpending(current))
2675 if (unlikely(uprobe_deny_signal()))
2679 * Do this once, we can't return to user-mode if freezing() == T.
2680 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2681 * thus do not need another check after return.
2686 spin_lock_irq(&sighand->siglock);
2689 * Every stopped thread goes here after wakeup. Check to see if
2690 * we should notify the parent, prepare_signal(SIGCONT) encodes
2691 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2693 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2696 if (signal->flags & SIGNAL_CLD_CONTINUED)
2697 why = CLD_CONTINUED;
2701 signal->flags &= ~SIGNAL_CLD_MASK;
2703 spin_unlock_irq(&sighand->siglock);
2706 * Notify the parent that we're continuing. This event is
2707 * always per-process and doesn't make whole lot of sense
2708 * for ptracers, who shouldn't consume the state via
2709 * wait(2) either, but, for backward compatibility, notify
2710 * the ptracer of the group leader too unless it's gonna be
2713 read_lock(&tasklist_lock);
2714 do_notify_parent_cldstop(current, false, why);
2716 if (ptrace_reparented(current->group_leader))
2717 do_notify_parent_cldstop(current->group_leader,
2719 read_unlock(&tasklist_lock);
2725 struct k_sigaction *ka;
2727 /* Has this task already been marked for death? */
2728 if (signal_group_exit(signal)) {
2729 ksig->info.si_signo = signr = SIGKILL;
2730 sigdelset(¤t->pending.signal, SIGKILL);
2731 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2732 &sighand->action[SIGKILL - 1]);
2733 recalc_sigpending();
2737 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2741 if (unlikely(current->jobctl &
2742 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2743 if (current->jobctl & JOBCTL_TRAP_MASK) {
2745 spin_unlock_irq(&sighand->siglock);
2746 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2753 * If the task is leaving the frozen state, let's update
2754 * cgroup counters and reset the frozen bit.
2756 if (unlikely(cgroup_task_frozen(current))) {
2757 spin_unlock_irq(&sighand->siglock);
2758 cgroup_leave_frozen(false);
2763 * Signals generated by the execution of an instruction
2764 * need to be delivered before any other pending signals
2765 * so that the instruction pointer in the signal stack
2766 * frame points to the faulting instruction.
2768 signr = dequeue_synchronous_signal(&ksig->info);
2770 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2773 break; /* will return 0 */
2775 if (unlikely(current->ptrace) && (signr != SIGKILL) &&
2776 !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) {
2777 signr = ptrace_signal(signr, &ksig->info);
2782 ka = &sighand->action[signr-1];
2784 /* Trace actually delivered signals. */
2785 trace_signal_deliver(signr, &ksig->info, ka);
2787 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2789 if (ka->sa.sa_handler != SIG_DFL) {
2790 /* Run the handler. */
2793 if (ka->sa.sa_flags & SA_ONESHOT)
2794 ka->sa.sa_handler = SIG_DFL;
2796 break; /* will return non-zero "signr" value */
2800 * Now we are doing the default action for this signal.
2802 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2806 * Global init gets no signals it doesn't want.
2807 * Container-init gets no signals it doesn't want from same
2810 * Note that if global/container-init sees a sig_kernel_only()
2811 * signal here, the signal must have been generated internally
2812 * or must have come from an ancestor namespace. In either
2813 * case, the signal cannot be dropped.
2815 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2816 !sig_kernel_only(signr))
2819 if (sig_kernel_stop(signr)) {
2821 * The default action is to stop all threads in
2822 * the thread group. The job control signals
2823 * do nothing in an orphaned pgrp, but SIGSTOP
2824 * always works. Note that siglock needs to be
2825 * dropped during the call to is_orphaned_pgrp()
2826 * because of lock ordering with tasklist_lock.
2827 * This allows an intervening SIGCONT to be posted.
2828 * We need to check for that and bail out if necessary.
2830 if (signr != SIGSTOP) {
2831 spin_unlock_irq(&sighand->siglock);
2833 /* signals can be posted during this window */
2835 if (is_current_pgrp_orphaned())
2838 spin_lock_irq(&sighand->siglock);
2841 if (likely(do_signal_stop(ksig->info.si_signo))) {
2842 /* It released the siglock. */
2847 * We didn't actually stop, due to a race
2848 * with SIGCONT or something like that.
2854 spin_unlock_irq(&sighand->siglock);
2855 if (unlikely(cgroup_task_frozen(current)))
2856 cgroup_leave_frozen(true);
2859 * Anything else is fatal, maybe with a core dump.
2861 current->flags |= PF_SIGNALED;
2863 if (sig_kernel_coredump(signr)) {
2864 if (print_fatal_signals)
2865 print_fatal_signal(ksig->info.si_signo);
2866 proc_coredump_connector(current);
2868 * If it was able to dump core, this kills all
2869 * other threads in the group and synchronizes with
2870 * their demise. If we lost the race with another
2871 * thread getting here, it set group_exit_code
2872 * first and our do_group_exit call below will use
2873 * that value and ignore the one we pass it.
2875 do_coredump(&ksig->info);
2879 * PF_IO_WORKER threads will catch and exit on fatal signals
2880 * themselves. They have cleanup that must be performed, so
2881 * we cannot call do_exit() on their behalf.
2883 if (current->flags & PF_IO_WORKER)
2887 * Death signals, no core dump.
2889 do_group_exit(ksig->info.si_signo);
2892 spin_unlock_irq(&sighand->siglock);
2896 if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
2897 hide_si_addr_tag_bits(ksig);
2899 return ksig->sig > 0;
2903 * signal_delivered -
2904 * @ksig: kernel signal struct
2905 * @stepping: nonzero if debugger single-step or block-step in use
2907 * This function should be called when a signal has successfully been
2908 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2909 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2910 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2912 static void signal_delivered(struct ksignal *ksig, int stepping)
2916 /* A signal was successfully delivered, and the
2917 saved sigmask was stored on the signal frame,
2918 and will be restored by sigreturn. So we can
2919 simply clear the restore sigmask flag. */
2920 clear_restore_sigmask();
2922 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2923 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2924 sigaddset(&blocked, ksig->sig);
2925 set_current_blocked(&blocked);
2926 if (current->sas_ss_flags & SS_AUTODISARM)
2927 sas_ss_reset(current);
2928 tracehook_signal_handler(stepping);
2931 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2934 force_sigsegv(ksig->sig);
2936 signal_delivered(ksig, stepping);
2940 * It could be that complete_signal() picked us to notify about the
2941 * group-wide signal. Other threads should be notified now to take
2942 * the shared signals in @which since we will not.
2944 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2947 struct task_struct *t;
2949 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2950 if (sigisemptyset(&retarget))
2954 while_each_thread(tsk, t) {
2955 if (t->flags & PF_EXITING)
2958 if (!has_pending_signals(&retarget, &t->blocked))
2960 /* Remove the signals this thread can handle. */
2961 sigandsets(&retarget, &retarget, &t->blocked);
2963 if (!task_sigpending(t))
2964 signal_wake_up(t, 0);
2966 if (sigisemptyset(&retarget))
2971 void exit_signals(struct task_struct *tsk)
2977 * @tsk is about to have PF_EXITING set - lock out users which
2978 * expect stable threadgroup.
2980 cgroup_threadgroup_change_begin(tsk);
2982 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2983 tsk->flags |= PF_EXITING;
2984 cgroup_threadgroup_change_end(tsk);
2988 spin_lock_irq(&tsk->sighand->siglock);
2990 * From now this task is not visible for group-wide signals,
2991 * see wants_signal(), do_signal_stop().
2993 tsk->flags |= PF_EXITING;
2995 cgroup_threadgroup_change_end(tsk);
2997 if (!task_sigpending(tsk))
3000 unblocked = tsk->blocked;
3001 signotset(&unblocked);
3002 retarget_shared_pending(tsk, &unblocked);
3004 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
3005 task_participate_group_stop(tsk))
3006 group_stop = CLD_STOPPED;
3008 spin_unlock_irq(&tsk->sighand->siglock);
3011 * If group stop has completed, deliver the notification. This
3012 * should always go to the real parent of the group leader.
3014 if (unlikely(group_stop)) {
3015 read_lock(&tasklist_lock);
3016 do_notify_parent_cldstop(tsk, false, group_stop);
3017 read_unlock(&tasklist_lock);
3022 * System call entry points.
3026 * sys_restart_syscall - restart a system call
3028 SYSCALL_DEFINE0(restart_syscall)
3030 struct restart_block *restart = ¤t->restart_block;
3031 return restart->fn(restart);
3034 long do_no_restart_syscall(struct restart_block *param)
3039 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
3041 if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
3042 sigset_t newblocked;
3043 /* A set of now blocked but previously unblocked signals. */
3044 sigandnsets(&newblocked, newset, ¤t->blocked);
3045 retarget_shared_pending(tsk, &newblocked);
3047 tsk->blocked = *newset;
3048 recalc_sigpending();
3052 * set_current_blocked - change current->blocked mask
3055 * It is wrong to change ->blocked directly, this helper should be used
3056 * to ensure the process can't miss a shared signal we are going to block.
3058 void set_current_blocked(sigset_t *newset)
3060 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
3061 __set_current_blocked(newset);
3064 void __set_current_blocked(const sigset_t *newset)
3066 struct task_struct *tsk = current;
3069 * In case the signal mask hasn't changed, there is nothing we need
3070 * to do. The current->blocked shouldn't be modified by other task.
3072 if (sigequalsets(&tsk->blocked, newset))
3075 spin_lock_irq(&tsk->sighand->siglock);
3076 __set_task_blocked(tsk, newset);
3077 spin_unlock_irq(&tsk->sighand->siglock);
3081 * This is also useful for kernel threads that want to temporarily
3082 * (or permanently) block certain signals.
3084 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
3085 * interface happily blocks "unblockable" signals like SIGKILL
3088 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
3090 struct task_struct *tsk = current;
3093 /* Lockless, only current can change ->blocked, never from irq */
3095 *oldset = tsk->blocked;
3099 sigorsets(&newset, &tsk->blocked, set);
3102 sigandnsets(&newset, &tsk->blocked, set);
3111 __set_current_blocked(&newset);
3114 EXPORT_SYMBOL(sigprocmask);
3117 * The api helps set app-provided sigmasks.
3119 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
3120 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
3122 * Note that it does set_restore_sigmask() in advance, so it must be always
3123 * paired with restore_saved_sigmask_unless() before return from syscall.
3125 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
3131 if (sigsetsize != sizeof(sigset_t))
3133 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
3136 set_restore_sigmask();
3137 current->saved_sigmask = current->blocked;
3138 set_current_blocked(&kmask);
3143 #ifdef CONFIG_COMPAT
3144 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3151 if (sigsetsize != sizeof(compat_sigset_t))
3153 if (get_compat_sigset(&kmask, umask))
3156 set_restore_sigmask();
3157 current->saved_sigmask = current->blocked;
3158 set_current_blocked(&kmask);
3165 * sys_rt_sigprocmask - change the list of currently blocked signals
3166 * @how: whether to add, remove, or set signals
3167 * @nset: stores pending signals
3168 * @oset: previous value of signal mask if non-null
3169 * @sigsetsize: size of sigset_t type
3171 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3172 sigset_t __user *, oset, size_t, sigsetsize)
3174 sigset_t old_set, new_set;
3177 /* XXX: Don't preclude handling different sized sigset_t's. */
3178 if (sigsetsize != sizeof(sigset_t))
3181 old_set = current->blocked;
3184 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3186 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3188 error = sigprocmask(how, &new_set, NULL);
3194 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3201 #ifdef CONFIG_COMPAT
3202 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3203 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3205 sigset_t old_set = current->blocked;
3207 /* XXX: Don't preclude handling different sized sigset_t's. */
3208 if (sigsetsize != sizeof(sigset_t))
3214 if (get_compat_sigset(&new_set, nset))
3216 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3218 error = sigprocmask(how, &new_set, NULL);
3222 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3226 static void do_sigpending(sigset_t *set)
3228 spin_lock_irq(¤t->sighand->siglock);
3229 sigorsets(set, ¤t->pending.signal,
3230 ¤t->signal->shared_pending.signal);
3231 spin_unlock_irq(¤t->sighand->siglock);
3233 /* Outside the lock because only this thread touches it. */
3234 sigandsets(set, ¤t->blocked, set);
3238 * sys_rt_sigpending - examine a pending signal that has been raised
3240 * @uset: stores pending signals
3241 * @sigsetsize: size of sigset_t type or larger
3243 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3247 if (sigsetsize > sizeof(*uset))
3250 do_sigpending(&set);
3252 if (copy_to_user(uset, &set, sigsetsize))
3258 #ifdef CONFIG_COMPAT
3259 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3260 compat_size_t, sigsetsize)
3264 if (sigsetsize > sizeof(*uset))
3267 do_sigpending(&set);
3269 return put_compat_sigset(uset, &set, sigsetsize);
3273 static const struct {
3274 unsigned char limit, layout;
3276 [SIGILL] = { NSIGILL, SIL_FAULT },
3277 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3278 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3279 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3280 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3282 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3284 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3285 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3286 [SIGSYS] = { NSIGSYS, SIL_SYS },
3289 static bool known_siginfo_layout(unsigned sig, int si_code)
3291 if (si_code == SI_KERNEL)
3293 else if ((si_code > SI_USER)) {
3294 if (sig_specific_sicodes(sig)) {
3295 if (si_code <= sig_sicodes[sig].limit)
3298 else if (si_code <= NSIGPOLL)
3301 else if (si_code >= SI_DETHREAD)
3303 else if (si_code == SI_ASYNCNL)
3308 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3310 enum siginfo_layout layout = SIL_KILL;
3311 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3312 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3313 (si_code <= sig_sicodes[sig].limit)) {
3314 layout = sig_sicodes[sig].layout;
3315 /* Handle the exceptions */
3316 if ((sig == SIGBUS) &&
3317 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3318 layout = SIL_FAULT_MCEERR;
3319 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3320 layout = SIL_FAULT_BNDERR;
3322 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3323 layout = SIL_FAULT_PKUERR;
3325 else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
3326 layout = SIL_FAULT_PERF_EVENT;
3327 else if (IS_ENABLED(CONFIG_SPARC) &&
3328 (sig == SIGILL) && (si_code == ILL_ILLTRP))
3329 layout = SIL_FAULT_TRAPNO;
3330 else if (IS_ENABLED(CONFIG_ALPHA) &&
3332 ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
3333 layout = SIL_FAULT_TRAPNO;
3335 else if (si_code <= NSIGPOLL)
3338 if (si_code == SI_TIMER)
3340 else if (si_code == SI_SIGIO)
3342 else if (si_code < 0)
3348 static inline char __user *si_expansion(const siginfo_t __user *info)
3350 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3353 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3355 char __user *expansion = si_expansion(to);
3356 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3358 if (clear_user(expansion, SI_EXPANSION_SIZE))
3363 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3364 const siginfo_t __user *from)
3366 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3367 char __user *expansion = si_expansion(from);
3368 char buf[SI_EXPANSION_SIZE];
3371 * An unknown si_code might need more than
3372 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3373 * extra bytes are 0. This guarantees copy_siginfo_to_user
3374 * will return this data to userspace exactly.
3376 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3378 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3386 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3387 const siginfo_t __user *from)
3389 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3391 to->si_signo = signo;
3392 return post_copy_siginfo_from_user(to, from);
3395 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3397 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3399 return post_copy_siginfo_from_user(to, from);
3402 #ifdef CONFIG_COMPAT
3404 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3405 * @to: compat siginfo destination
3406 * @from: kernel siginfo source
3408 * Note: This function does not work properly for the SIGCHLD on x32, but
3409 * fortunately it doesn't have to. The only valid callers for this function are
3410 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3411 * The latter does not care because SIGCHLD will never cause a coredump.
3413 void copy_siginfo_to_external32(struct compat_siginfo *to,
3414 const struct kernel_siginfo *from)
3416 memset(to, 0, sizeof(*to));
3418 to->si_signo = from->si_signo;
3419 to->si_errno = from->si_errno;
3420 to->si_code = from->si_code;
3421 switch(siginfo_layout(from->si_signo, from->si_code)) {
3423 to->si_pid = from->si_pid;
3424 to->si_uid = from->si_uid;
3427 to->si_tid = from->si_tid;
3428 to->si_overrun = from->si_overrun;
3429 to->si_int = from->si_int;
3432 to->si_band = from->si_band;
3433 to->si_fd = from->si_fd;
3436 to->si_addr = ptr_to_compat(from->si_addr);
3438 case SIL_FAULT_TRAPNO:
3439 to->si_addr = ptr_to_compat(from->si_addr);
3440 to->si_trapno = from->si_trapno;
3442 case SIL_FAULT_MCEERR:
3443 to->si_addr = ptr_to_compat(from->si_addr);
3444 to->si_addr_lsb = from->si_addr_lsb;
3446 case SIL_FAULT_BNDERR:
3447 to->si_addr = ptr_to_compat(from->si_addr);
3448 to->si_lower = ptr_to_compat(from->si_lower);
3449 to->si_upper = ptr_to_compat(from->si_upper);
3451 case SIL_FAULT_PKUERR:
3452 to->si_addr = ptr_to_compat(from->si_addr);
3453 to->si_pkey = from->si_pkey;
3455 case SIL_FAULT_PERF_EVENT:
3456 to->si_addr = ptr_to_compat(from->si_addr);
3457 to->si_perf_data = from->si_perf_data;
3458 to->si_perf_type = from->si_perf_type;
3459 to->si_perf_flags = from->si_perf_flags;
3462 to->si_pid = from->si_pid;
3463 to->si_uid = from->si_uid;
3464 to->si_status = from->si_status;
3465 to->si_utime = from->si_utime;
3466 to->si_stime = from->si_stime;
3469 to->si_pid = from->si_pid;
3470 to->si_uid = from->si_uid;
3471 to->si_int = from->si_int;
3474 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3475 to->si_syscall = from->si_syscall;
3476 to->si_arch = from->si_arch;
3481 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3482 const struct kernel_siginfo *from)
3484 struct compat_siginfo new;
3486 copy_siginfo_to_external32(&new, from);
3487 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3492 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3493 const struct compat_siginfo *from)
3496 to->si_signo = from->si_signo;
3497 to->si_errno = from->si_errno;
3498 to->si_code = from->si_code;
3499 switch(siginfo_layout(from->si_signo, from->si_code)) {
3501 to->si_pid = from->si_pid;
3502 to->si_uid = from->si_uid;
3505 to->si_tid = from->si_tid;
3506 to->si_overrun = from->si_overrun;
3507 to->si_int = from->si_int;
3510 to->si_band = from->si_band;
3511 to->si_fd = from->si_fd;
3514 to->si_addr = compat_ptr(from->si_addr);
3516 case SIL_FAULT_TRAPNO:
3517 to->si_addr = compat_ptr(from->si_addr);
3518 to->si_trapno = from->si_trapno;
3520 case SIL_FAULT_MCEERR:
3521 to->si_addr = compat_ptr(from->si_addr);
3522 to->si_addr_lsb = from->si_addr_lsb;
3524 case SIL_FAULT_BNDERR:
3525 to->si_addr = compat_ptr(from->si_addr);
3526 to->si_lower = compat_ptr(from->si_lower);
3527 to->si_upper = compat_ptr(from->si_upper);
3529 case SIL_FAULT_PKUERR:
3530 to->si_addr = compat_ptr(from->si_addr);
3531 to->si_pkey = from->si_pkey;
3533 case SIL_FAULT_PERF_EVENT:
3534 to->si_addr = compat_ptr(from->si_addr);
3535 to->si_perf_data = from->si_perf_data;
3536 to->si_perf_type = from->si_perf_type;
3537 to->si_perf_flags = from->si_perf_flags;
3540 to->si_pid = from->si_pid;
3541 to->si_uid = from->si_uid;
3542 to->si_status = from->si_status;
3543 #ifdef CONFIG_X86_X32_ABI
3544 if (in_x32_syscall()) {
3545 to->si_utime = from->_sifields._sigchld_x32._utime;
3546 to->si_stime = from->_sifields._sigchld_x32._stime;
3550 to->si_utime = from->si_utime;
3551 to->si_stime = from->si_stime;
3555 to->si_pid = from->si_pid;
3556 to->si_uid = from->si_uid;
3557 to->si_int = from->si_int;
3560 to->si_call_addr = compat_ptr(from->si_call_addr);
3561 to->si_syscall = from->si_syscall;
3562 to->si_arch = from->si_arch;
3568 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3569 const struct compat_siginfo __user *ufrom)
3571 struct compat_siginfo from;
3573 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3576 from.si_signo = signo;
3577 return post_copy_siginfo_from_user32(to, &from);
3580 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3581 const struct compat_siginfo __user *ufrom)
3583 struct compat_siginfo from;
3585 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3588 return post_copy_siginfo_from_user32(to, &from);
3590 #endif /* CONFIG_COMPAT */
3593 * do_sigtimedwait - wait for queued signals specified in @which
3594 * @which: queued signals to wait for
3595 * @info: if non-null, the signal's siginfo is returned here
3596 * @ts: upper bound on process time suspension
3598 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3599 const struct timespec64 *ts)
3601 ktime_t *to = NULL, timeout = KTIME_MAX;
3602 struct task_struct *tsk = current;
3603 sigset_t mask = *which;
3607 if (!timespec64_valid(ts))
3609 timeout = timespec64_to_ktime(*ts);
3614 * Invert the set of allowed signals to get those we want to block.
3616 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3619 spin_lock_irq(&tsk->sighand->siglock);
3620 sig = dequeue_signal(tsk, &mask, info);
3621 if (!sig && timeout) {
3623 * None ready, temporarily unblock those we're interested
3624 * while we are sleeping in so that we'll be awakened when
3625 * they arrive. Unblocking is always fine, we can avoid
3626 * set_current_blocked().
3628 tsk->real_blocked = tsk->blocked;
3629 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3630 recalc_sigpending();
3631 spin_unlock_irq(&tsk->sighand->siglock);
3633 __set_current_state(TASK_INTERRUPTIBLE);
3634 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3636 spin_lock_irq(&tsk->sighand->siglock);
3637 __set_task_blocked(tsk, &tsk->real_blocked);
3638 sigemptyset(&tsk->real_blocked);
3639 sig = dequeue_signal(tsk, &mask, info);
3641 spin_unlock_irq(&tsk->sighand->siglock);
3645 return ret ? -EINTR : -EAGAIN;
3649 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3651 * @uthese: queued signals to wait for
3652 * @uinfo: if non-null, the signal's siginfo is returned here
3653 * @uts: upper bound on process time suspension
3654 * @sigsetsize: size of sigset_t type
3656 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3657 siginfo_t __user *, uinfo,
3658 const struct __kernel_timespec __user *, uts,
3662 struct timespec64 ts;
3663 kernel_siginfo_t info;
3666 /* XXX: Don't preclude handling different sized sigset_t's. */
3667 if (sigsetsize != sizeof(sigset_t))
3670 if (copy_from_user(&these, uthese, sizeof(these)))
3674 if (get_timespec64(&ts, uts))
3678 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3680 if (ret > 0 && uinfo) {
3681 if (copy_siginfo_to_user(uinfo, &info))
3688 #ifdef CONFIG_COMPAT_32BIT_TIME
3689 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3690 siginfo_t __user *, uinfo,
3691 const struct old_timespec32 __user *, uts,
3695 struct timespec64 ts;
3696 kernel_siginfo_t info;
3699 if (sigsetsize != sizeof(sigset_t))
3702 if (copy_from_user(&these, uthese, sizeof(these)))
3706 if (get_old_timespec32(&ts, uts))
3710 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3712 if (ret > 0 && uinfo) {
3713 if (copy_siginfo_to_user(uinfo, &info))
3721 #ifdef CONFIG_COMPAT
3722 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3723 struct compat_siginfo __user *, uinfo,
3724 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3727 struct timespec64 t;
3728 kernel_siginfo_t info;
3731 if (sigsetsize != sizeof(sigset_t))
3734 if (get_compat_sigset(&s, uthese))
3738 if (get_timespec64(&t, uts))
3742 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3744 if (ret > 0 && uinfo) {
3745 if (copy_siginfo_to_user32(uinfo, &info))
3752 #ifdef CONFIG_COMPAT_32BIT_TIME
3753 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3754 struct compat_siginfo __user *, uinfo,
3755 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3758 struct timespec64 t;
3759 kernel_siginfo_t info;
3762 if (sigsetsize != sizeof(sigset_t))
3765 if (get_compat_sigset(&s, uthese))
3769 if (get_old_timespec32(&t, uts))
3773 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3775 if (ret > 0 && uinfo) {
3776 if (copy_siginfo_to_user32(uinfo, &info))
3785 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3787 clear_siginfo(info);
3788 info->si_signo = sig;
3790 info->si_code = SI_USER;
3791 info->si_pid = task_tgid_vnr(current);
3792 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3796 * sys_kill - send a signal to a process
3797 * @pid: the PID of the process
3798 * @sig: signal to be sent
3800 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3802 struct kernel_siginfo info;
3804 prepare_kill_siginfo(sig, &info);
3806 return kill_something_info(sig, &info, pid);
3810 * Verify that the signaler and signalee either are in the same pid namespace
3811 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3814 static bool access_pidfd_pidns(struct pid *pid)
3816 struct pid_namespace *active = task_active_pid_ns(current);
3817 struct pid_namespace *p = ns_of_pid(pid);
3830 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
3831 siginfo_t __user *info)
3833 #ifdef CONFIG_COMPAT
3835 * Avoid hooking up compat syscalls and instead handle necessary
3836 * conversions here. Note, this is a stop-gap measure and should not be
3837 * considered a generic solution.
3839 if (in_compat_syscall())
3840 return copy_siginfo_from_user32(
3841 kinfo, (struct compat_siginfo __user *)info);
3843 return copy_siginfo_from_user(kinfo, info);
3846 static struct pid *pidfd_to_pid(const struct file *file)
3850 pid = pidfd_pid(file);
3854 return tgid_pidfd_to_pid(file);
3858 * sys_pidfd_send_signal - Signal a process through a pidfd
3859 * @pidfd: file descriptor of the process
3860 * @sig: signal to send
3861 * @info: signal info
3862 * @flags: future flags
3864 * The syscall currently only signals via PIDTYPE_PID which covers
3865 * kill(<positive-pid>, <signal>. It does not signal threads or process
3867 * In order to extend the syscall to threads and process groups the @flags
3868 * argument should be used. In essence, the @flags argument will determine
3869 * what is signaled and not the file descriptor itself. Put in other words,
3870 * grouping is a property of the flags argument not a property of the file
3873 * Return: 0 on success, negative errno on failure
3875 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3876 siginfo_t __user *, info, unsigned int, flags)
3881 kernel_siginfo_t kinfo;
3883 /* Enforce flags be set to 0 until we add an extension. */
3891 /* Is this a pidfd? */
3892 pid = pidfd_to_pid(f.file);
3899 if (!access_pidfd_pidns(pid))
3903 ret = copy_siginfo_from_user_any(&kinfo, info);
3908 if (unlikely(sig != kinfo.si_signo))
3911 /* Only allow sending arbitrary signals to yourself. */
3913 if ((task_pid(current) != pid) &&
3914 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3917 prepare_kill_siginfo(sig, &kinfo);
3920 ret = kill_pid_info(sig, &kinfo, pid);
3928 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3930 struct task_struct *p;
3934 p = find_task_by_vpid(pid);
3935 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3936 error = check_kill_permission(sig, info, p);
3938 * The null signal is a permissions and process existence
3939 * probe. No signal is actually delivered.
3941 if (!error && sig) {
3942 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3944 * If lock_task_sighand() failed we pretend the task
3945 * dies after receiving the signal. The window is tiny,
3946 * and the signal is private anyway.
3948 if (unlikely(error == -ESRCH))
3957 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3959 struct kernel_siginfo info;
3961 clear_siginfo(&info);
3962 info.si_signo = sig;
3964 info.si_code = SI_TKILL;
3965 info.si_pid = task_tgid_vnr(current);
3966 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3968 return do_send_specific(tgid, pid, sig, &info);
3972 * sys_tgkill - send signal to one specific thread
3973 * @tgid: the thread group ID of the thread
3974 * @pid: the PID of the thread
3975 * @sig: signal to be sent
3977 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3978 * exists but it's not belonging to the target process anymore. This
3979 * method solves the problem of threads exiting and PIDs getting reused.
3981 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3983 /* This is only valid for single tasks */
3984 if (pid <= 0 || tgid <= 0)
3987 return do_tkill(tgid, pid, sig);
3991 * sys_tkill - send signal to one specific task
3992 * @pid: the PID of the task
3993 * @sig: signal to be sent
3995 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3997 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3999 /* This is only valid for single tasks */
4003 return do_tkill(0, pid, sig);
4006 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
4008 /* Not even root can pretend to send signals from the kernel.
4009 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4011 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4012 (task_pid_vnr(current) != pid))
4015 /* POSIX.1b doesn't mention process groups. */
4016 return kill_proc_info(sig, info, pid);
4020 * sys_rt_sigqueueinfo - send signal information to a signal
4021 * @pid: the PID of the thread
4022 * @sig: signal to be sent
4023 * @uinfo: signal info to be sent
4025 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
4026 siginfo_t __user *, uinfo)
4028 kernel_siginfo_t info;
4029 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4032 return do_rt_sigqueueinfo(pid, sig, &info);
4035 #ifdef CONFIG_COMPAT
4036 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
4039 struct compat_siginfo __user *, uinfo)
4041 kernel_siginfo_t info;
4042 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4045 return do_rt_sigqueueinfo(pid, sig, &info);
4049 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
4051 /* This is only valid for single tasks */
4052 if (pid <= 0 || tgid <= 0)
4055 /* Not even root can pretend to send signals from the kernel.
4056 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4058 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4059 (task_pid_vnr(current) != pid))
4062 return do_send_specific(tgid, pid, sig, info);
4065 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
4066 siginfo_t __user *, uinfo)
4068 kernel_siginfo_t info;
4069 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4072 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4075 #ifdef CONFIG_COMPAT
4076 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
4080 struct compat_siginfo __user *, uinfo)
4082 kernel_siginfo_t info;
4083 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4086 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4091 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
4093 void kernel_sigaction(int sig, __sighandler_t action)
4095 spin_lock_irq(¤t->sighand->siglock);
4096 current->sighand->action[sig - 1].sa.sa_handler = action;
4097 if (action == SIG_IGN) {
4101 sigaddset(&mask, sig);
4103 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
4104 flush_sigqueue_mask(&mask, ¤t->pending);
4105 recalc_sigpending();
4107 spin_unlock_irq(¤t->sighand->siglock);
4109 EXPORT_SYMBOL(kernel_sigaction);
4111 void __weak sigaction_compat_abi(struct k_sigaction *act,
4112 struct k_sigaction *oact)
4116 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
4118 struct task_struct *p = current, *t;
4119 struct k_sigaction *k;
4122 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
4125 k = &p->sighand->action[sig-1];
4127 spin_lock_irq(&p->sighand->siglock);
4128 if (k->sa.sa_flags & SA_IMMUTABLE) {
4129 spin_unlock_irq(&p->sighand->siglock);
4136 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
4137 * e.g. by having an architecture use the bit in their uapi.
4139 BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
4142 * Clear unknown flag bits in order to allow userspace to detect missing
4143 * support for flag bits and to allow the kernel to use non-uapi bits
4147 act->sa.sa_flags &= UAPI_SA_FLAGS;
4149 oact->sa.sa_flags &= UAPI_SA_FLAGS;
4151 sigaction_compat_abi(act, oact);
4154 sigdelsetmask(&act->sa.sa_mask,
4155 sigmask(SIGKILL) | sigmask(SIGSTOP));
4159 * "Setting a signal action to SIG_IGN for a signal that is
4160 * pending shall cause the pending signal to be discarded,
4161 * whether or not it is blocked."
4163 * "Setting a signal action to SIG_DFL for a signal that is
4164 * pending and whose default action is to ignore the signal
4165 * (for example, SIGCHLD), shall cause the pending signal to
4166 * be discarded, whether or not it is blocked"
4168 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
4170 sigaddset(&mask, sig);
4171 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
4172 for_each_thread(p, t)
4173 flush_sigqueue_mask(&mask, &t->pending);
4177 spin_unlock_irq(&p->sighand->siglock);
4182 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4185 struct task_struct *t = current;
4188 memset(oss, 0, sizeof(stack_t));
4189 oss->ss_sp = (void __user *) t->sas_ss_sp;
4190 oss->ss_size = t->sas_ss_size;
4191 oss->ss_flags = sas_ss_flags(sp) |
4192 (current->sas_ss_flags & SS_FLAG_BITS);
4196 void __user *ss_sp = ss->ss_sp;
4197 size_t ss_size = ss->ss_size;
4198 unsigned ss_flags = ss->ss_flags;
4201 if (unlikely(on_sig_stack(sp)))
4204 ss_mode = ss_flags & ~SS_FLAG_BITS;
4205 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4209 if (ss_mode == SS_DISABLE) {
4213 if (unlikely(ss_size < min_ss_size))
4217 t->sas_ss_sp = (unsigned long) ss_sp;
4218 t->sas_ss_size = ss_size;
4219 t->sas_ss_flags = ss_flags;
4224 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4228 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4230 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4231 current_user_stack_pointer(),
4233 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4238 int restore_altstack(const stack_t __user *uss)
4241 if (copy_from_user(&new, uss, sizeof(stack_t)))
4243 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4245 /* squash all but EFAULT for now */
4249 int __save_altstack(stack_t __user *uss, unsigned long sp)
4251 struct task_struct *t = current;
4252 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4253 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4254 __put_user(t->sas_ss_size, &uss->ss_size);
4258 #ifdef CONFIG_COMPAT
4259 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4260 compat_stack_t __user *uoss_ptr)
4266 compat_stack_t uss32;
4267 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4269 uss.ss_sp = compat_ptr(uss32.ss_sp);
4270 uss.ss_flags = uss32.ss_flags;
4271 uss.ss_size = uss32.ss_size;
4273 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4274 compat_user_stack_pointer(),
4275 COMPAT_MINSIGSTKSZ);
4276 if (ret >= 0 && uoss_ptr) {
4278 memset(&old, 0, sizeof(old));
4279 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4280 old.ss_flags = uoss.ss_flags;
4281 old.ss_size = uoss.ss_size;
4282 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4288 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4289 const compat_stack_t __user *, uss_ptr,
4290 compat_stack_t __user *, uoss_ptr)
4292 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4295 int compat_restore_altstack(const compat_stack_t __user *uss)
4297 int err = do_compat_sigaltstack(uss, NULL);
4298 /* squash all but -EFAULT for now */
4299 return err == -EFAULT ? err : 0;
4302 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4305 struct task_struct *t = current;
4306 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4308 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4309 __put_user(t->sas_ss_size, &uss->ss_size);
4314 #ifdef __ARCH_WANT_SYS_SIGPENDING
4317 * sys_sigpending - examine pending signals
4318 * @uset: where mask of pending signal is returned
4320 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4324 if (sizeof(old_sigset_t) > sizeof(*uset))
4327 do_sigpending(&set);
4329 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4335 #ifdef CONFIG_COMPAT
4336 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4340 do_sigpending(&set);
4342 return put_user(set.sig[0], set32);
4348 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4350 * sys_sigprocmask - examine and change blocked signals
4351 * @how: whether to add, remove, or set signals
4352 * @nset: signals to add or remove (if non-null)
4353 * @oset: previous value of signal mask if non-null
4355 * Some platforms have their own version with special arguments;
4356 * others support only sys_rt_sigprocmask.
4359 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4360 old_sigset_t __user *, oset)
4362 old_sigset_t old_set, new_set;
4363 sigset_t new_blocked;
4365 old_set = current->blocked.sig[0];
4368 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4371 new_blocked = current->blocked;
4375 sigaddsetmask(&new_blocked, new_set);
4378 sigdelsetmask(&new_blocked, new_set);
4381 new_blocked.sig[0] = new_set;
4387 set_current_blocked(&new_blocked);
4391 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4397 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4399 #ifndef CONFIG_ODD_RT_SIGACTION
4401 * sys_rt_sigaction - alter an action taken by a process
4402 * @sig: signal to be sent
4403 * @act: new sigaction
4404 * @oact: used to save the previous sigaction
4405 * @sigsetsize: size of sigset_t type
4407 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4408 const struct sigaction __user *, act,
4409 struct sigaction __user *, oact,
4412 struct k_sigaction new_sa, old_sa;
4415 /* XXX: Don't preclude handling different sized sigset_t's. */
4416 if (sigsetsize != sizeof(sigset_t))
4419 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4422 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4426 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4431 #ifdef CONFIG_COMPAT
4432 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4433 const struct compat_sigaction __user *, act,
4434 struct compat_sigaction __user *, oact,
4435 compat_size_t, sigsetsize)
4437 struct k_sigaction new_ka, old_ka;
4438 #ifdef __ARCH_HAS_SA_RESTORER
4439 compat_uptr_t restorer;
4443 /* XXX: Don't preclude handling different sized sigset_t's. */
4444 if (sigsetsize != sizeof(compat_sigset_t))
4448 compat_uptr_t handler;
4449 ret = get_user(handler, &act->sa_handler);
4450 new_ka.sa.sa_handler = compat_ptr(handler);
4451 #ifdef __ARCH_HAS_SA_RESTORER
4452 ret |= get_user(restorer, &act->sa_restorer);
4453 new_ka.sa.sa_restorer = compat_ptr(restorer);
4455 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4456 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4461 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4463 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4465 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4466 sizeof(oact->sa_mask));
4467 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4468 #ifdef __ARCH_HAS_SA_RESTORER
4469 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4470 &oact->sa_restorer);
4476 #endif /* !CONFIG_ODD_RT_SIGACTION */
4478 #ifdef CONFIG_OLD_SIGACTION
4479 SYSCALL_DEFINE3(sigaction, int, sig,
4480 const struct old_sigaction __user *, act,
4481 struct old_sigaction __user *, oact)
4483 struct k_sigaction new_ka, old_ka;
4488 if (!access_ok(act, sizeof(*act)) ||
4489 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4490 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4491 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4492 __get_user(mask, &act->sa_mask))
4494 #ifdef __ARCH_HAS_KA_RESTORER
4495 new_ka.ka_restorer = NULL;
4497 siginitset(&new_ka.sa.sa_mask, mask);
4500 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4503 if (!access_ok(oact, sizeof(*oact)) ||
4504 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4505 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4506 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4507 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4514 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4515 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4516 const struct compat_old_sigaction __user *, act,
4517 struct compat_old_sigaction __user *, oact)
4519 struct k_sigaction new_ka, old_ka;
4521 compat_old_sigset_t mask;
4522 compat_uptr_t handler, restorer;
4525 if (!access_ok(act, sizeof(*act)) ||
4526 __get_user(handler, &act->sa_handler) ||
4527 __get_user(restorer, &act->sa_restorer) ||
4528 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4529 __get_user(mask, &act->sa_mask))
4532 #ifdef __ARCH_HAS_KA_RESTORER
4533 new_ka.ka_restorer = NULL;
4535 new_ka.sa.sa_handler = compat_ptr(handler);
4536 new_ka.sa.sa_restorer = compat_ptr(restorer);
4537 siginitset(&new_ka.sa.sa_mask, mask);
4540 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4543 if (!access_ok(oact, sizeof(*oact)) ||
4544 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4545 &oact->sa_handler) ||
4546 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4547 &oact->sa_restorer) ||
4548 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4549 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4556 #ifdef CONFIG_SGETMASK_SYSCALL
4559 * For backwards compatibility. Functionality superseded by sigprocmask.
4561 SYSCALL_DEFINE0(sgetmask)
4564 return current->blocked.sig[0];
4567 SYSCALL_DEFINE1(ssetmask, int, newmask)
4569 int old = current->blocked.sig[0];
4572 siginitset(&newset, newmask);
4573 set_current_blocked(&newset);
4577 #endif /* CONFIG_SGETMASK_SYSCALL */
4579 #ifdef __ARCH_WANT_SYS_SIGNAL
4581 * For backwards compatibility. Functionality superseded by sigaction.
4583 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4585 struct k_sigaction new_sa, old_sa;
4588 new_sa.sa.sa_handler = handler;
4589 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4590 sigemptyset(&new_sa.sa.sa_mask);
4592 ret = do_sigaction(sig, &new_sa, &old_sa);
4594 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4596 #endif /* __ARCH_WANT_SYS_SIGNAL */
4598 #ifdef __ARCH_WANT_SYS_PAUSE
4600 SYSCALL_DEFINE0(pause)
4602 while (!signal_pending(current)) {
4603 __set_current_state(TASK_INTERRUPTIBLE);
4606 return -ERESTARTNOHAND;
4611 static int sigsuspend(sigset_t *set)
4613 current->saved_sigmask = current->blocked;
4614 set_current_blocked(set);
4616 while (!signal_pending(current)) {
4617 __set_current_state(TASK_INTERRUPTIBLE);
4620 set_restore_sigmask();
4621 return -ERESTARTNOHAND;
4625 * sys_rt_sigsuspend - replace the signal mask for a value with the
4626 * @unewset value until a signal is received
4627 * @unewset: new signal mask value
4628 * @sigsetsize: size of sigset_t type
4630 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4634 /* XXX: Don't preclude handling different sized sigset_t's. */
4635 if (sigsetsize != sizeof(sigset_t))
4638 if (copy_from_user(&newset, unewset, sizeof(newset)))
4640 return sigsuspend(&newset);
4643 #ifdef CONFIG_COMPAT
4644 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4648 /* XXX: Don't preclude handling different sized sigset_t's. */
4649 if (sigsetsize != sizeof(sigset_t))
4652 if (get_compat_sigset(&newset, unewset))
4654 return sigsuspend(&newset);
4658 #ifdef CONFIG_OLD_SIGSUSPEND
4659 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4662 siginitset(&blocked, mask);
4663 return sigsuspend(&blocked);
4666 #ifdef CONFIG_OLD_SIGSUSPEND3
4667 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4670 siginitset(&blocked, mask);
4671 return sigsuspend(&blocked);
4675 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4680 static inline void siginfo_buildtime_checks(void)
4682 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4684 /* Verify the offsets in the two siginfos match */
4685 #define CHECK_OFFSET(field) \
4686 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4689 CHECK_OFFSET(si_pid);
4690 CHECK_OFFSET(si_uid);
4693 CHECK_OFFSET(si_tid);
4694 CHECK_OFFSET(si_overrun);
4695 CHECK_OFFSET(si_value);
4698 CHECK_OFFSET(si_pid);
4699 CHECK_OFFSET(si_uid);
4700 CHECK_OFFSET(si_value);
4703 CHECK_OFFSET(si_pid);
4704 CHECK_OFFSET(si_uid);
4705 CHECK_OFFSET(si_status);
4706 CHECK_OFFSET(si_utime);
4707 CHECK_OFFSET(si_stime);
4710 CHECK_OFFSET(si_addr);
4711 CHECK_OFFSET(si_trapno);
4712 CHECK_OFFSET(si_addr_lsb);
4713 CHECK_OFFSET(si_lower);
4714 CHECK_OFFSET(si_upper);
4715 CHECK_OFFSET(si_pkey);
4716 CHECK_OFFSET(si_perf_data);
4717 CHECK_OFFSET(si_perf_type);
4718 CHECK_OFFSET(si_perf_flags);
4721 CHECK_OFFSET(si_band);
4722 CHECK_OFFSET(si_fd);
4725 CHECK_OFFSET(si_call_addr);
4726 CHECK_OFFSET(si_syscall);
4727 CHECK_OFFSET(si_arch);
4731 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4732 offsetof(struct siginfo, si_addr));
4733 if (sizeof(int) == sizeof(void __user *)) {
4734 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4735 sizeof(void __user *));
4737 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4738 sizeof_field(struct siginfo, si_uid)) !=
4739 sizeof(void __user *));
4740 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4741 offsetof(struct siginfo, si_uid));
4743 #ifdef CONFIG_COMPAT
4744 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4745 offsetof(struct compat_siginfo, si_addr));
4746 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4747 sizeof(compat_uptr_t));
4748 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4749 sizeof_field(struct siginfo, si_pid));
4753 void __init signals_init(void)
4755 siginfo_buildtime_checks();
4757 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT);
4760 #ifdef CONFIG_KGDB_KDB
4761 #include <linux/kdb.h>
4763 * kdb_send_sig - Allows kdb to send signals without exposing
4764 * signal internals. This function checks if the required locks are
4765 * available before calling the main signal code, to avoid kdb
4768 void kdb_send_sig(struct task_struct *t, int sig)
4770 static struct task_struct *kdb_prev_t;
4772 if (!spin_trylock(&t->sighand->siglock)) {
4773 kdb_printf("Can't do kill command now.\n"
4774 "The sigmask lock is held somewhere else in "
4775 "kernel, try again later\n");
4778 new_t = kdb_prev_t != t;
4780 if (!task_is_running(t) && new_t) {
4781 spin_unlock(&t->sighand->siglock);
4782 kdb_printf("Process is not RUNNING, sending a signal from "
4783 "kdb risks deadlock\n"
4784 "on the run queue locks. "
4785 "The signal has _not_ been sent.\n"
4786 "Reissue the kill command if you want to risk "
4790 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4791 spin_unlock(&t->sighand->siglock);
4793 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4796 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4798 #endif /* CONFIG_KGDB_KDB */