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>
59 * SLAB caches for signal bits.
62 static struct kmem_cache *sigqueue_cachep;
64 int print_fatal_signals __read_mostly;
66 static void __user *sig_handler(struct task_struct *t, int sig)
68 return t->sighand->action[sig - 1].sa.sa_handler;
71 static inline bool sig_handler_ignored(void __user *handler, int sig)
73 /* Is it explicitly or implicitly ignored? */
74 return handler == SIG_IGN ||
75 (handler == SIG_DFL && sig_kernel_ignore(sig));
78 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
82 handler = sig_handler(t, sig);
84 /* SIGKILL and SIGSTOP may not be sent to the global init */
85 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
88 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
89 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
92 /* Only allow kernel generated signals to this kthread */
93 if (unlikely((t->flags & PF_KTHREAD) &&
94 (handler == SIG_KTHREAD_KERNEL) && !force))
97 return sig_handler_ignored(handler, sig);
100 static bool sig_ignored(struct task_struct *t, int sig, bool force)
103 * Blocked signals are never ignored, since the
104 * signal handler may change by the time it is
107 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
111 * Tracers may want to know about even ignored signal unless it
112 * is SIGKILL which can't be reported anyway but can be ignored
113 * by SIGNAL_UNKILLABLE task.
115 if (t->ptrace && sig != SIGKILL)
118 return sig_task_ignored(t, sig, force);
122 * Re-calculate pending state from the set of locally pending
123 * signals, globally pending signals, and blocked signals.
125 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
130 switch (_NSIG_WORDS) {
132 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
133 ready |= signal->sig[i] &~ blocked->sig[i];
136 case 4: ready = signal->sig[3] &~ blocked->sig[3];
137 ready |= signal->sig[2] &~ blocked->sig[2];
138 ready |= signal->sig[1] &~ blocked->sig[1];
139 ready |= signal->sig[0] &~ blocked->sig[0];
142 case 2: ready = signal->sig[1] &~ blocked->sig[1];
143 ready |= signal->sig[0] &~ blocked->sig[0];
146 case 1: ready = signal->sig[0] &~ blocked->sig[0];
151 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
153 static bool recalc_sigpending_tsk(struct task_struct *t)
155 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
156 PENDING(&t->pending, &t->blocked) ||
157 PENDING(&t->signal->shared_pending, &t->blocked) ||
158 cgroup_task_frozen(t)) {
159 set_tsk_thread_flag(t, TIF_SIGPENDING);
164 * We must never clear the flag in another thread, or in current
165 * when it's possible the current syscall is returning -ERESTART*.
166 * So we don't clear it here, and only callers who know they should do.
172 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
173 * This is superfluous when called on current, the wakeup is a harmless no-op.
175 void recalc_sigpending_and_wake(struct task_struct *t)
177 if (recalc_sigpending_tsk(t))
178 signal_wake_up(t, 0);
181 void recalc_sigpending(void)
183 if (!recalc_sigpending_tsk(current) && !freezing(current))
184 clear_thread_flag(TIF_SIGPENDING);
187 EXPORT_SYMBOL(recalc_sigpending);
189 void calculate_sigpending(void)
191 /* Have any signals or users of TIF_SIGPENDING been delayed
194 spin_lock_irq(¤t->sighand->siglock);
195 set_tsk_thread_flag(current, TIF_SIGPENDING);
197 spin_unlock_irq(¤t->sighand->siglock);
200 /* Given the mask, find the first available signal that should be serviced. */
202 #define SYNCHRONOUS_MASK \
203 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
204 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
206 int next_signal(struct sigpending *pending, sigset_t *mask)
208 unsigned long i, *s, *m, x;
211 s = pending->signal.sig;
215 * Handle the first word specially: it contains the
216 * synchronous signals that need to be dequeued first.
220 if (x & SYNCHRONOUS_MASK)
221 x &= SYNCHRONOUS_MASK;
226 switch (_NSIG_WORDS) {
228 for (i = 1; i < _NSIG_WORDS; ++i) {
232 sig = ffz(~x) + i*_NSIG_BPW + 1;
241 sig = ffz(~x) + _NSIG_BPW + 1;
252 static inline void print_dropped_signal(int sig)
254 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
256 if (!print_fatal_signals)
259 if (!__ratelimit(&ratelimit_state))
262 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
263 current->comm, current->pid, sig);
267 * task_set_jobctl_pending - set jobctl pending bits
269 * @mask: pending bits to set
271 * Clear @mask from @task->jobctl. @mask must be subset of
272 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
273 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
274 * cleared. If @task is already being killed or exiting, this function
278 * Must be called with @task->sighand->siglock held.
281 * %true if @mask is set, %false if made noop because @task was dying.
283 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
285 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
286 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
287 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
289 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
292 if (mask & JOBCTL_STOP_SIGMASK)
293 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
295 task->jobctl |= mask;
300 * task_clear_jobctl_trapping - clear jobctl trapping bit
303 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
304 * Clear it and wake up the ptracer. Note that we don't need any further
305 * locking. @task->siglock guarantees that @task->parent points to the
309 * Must be called with @task->sighand->siglock held.
311 void task_clear_jobctl_trapping(struct task_struct *task)
313 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
314 task->jobctl &= ~JOBCTL_TRAPPING;
315 smp_mb(); /* advised by wake_up_bit() */
316 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
321 * task_clear_jobctl_pending - clear jobctl pending bits
323 * @mask: pending bits to clear
325 * Clear @mask from @task->jobctl. @mask must be subset of
326 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
327 * STOP bits are cleared together.
329 * If clearing of @mask leaves no stop or trap pending, this function calls
330 * task_clear_jobctl_trapping().
333 * Must be called with @task->sighand->siglock held.
335 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
337 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
339 if (mask & JOBCTL_STOP_PENDING)
340 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
342 task->jobctl &= ~mask;
344 if (!(task->jobctl & JOBCTL_PENDING_MASK))
345 task_clear_jobctl_trapping(task);
349 * task_participate_group_stop - participate in a group stop
350 * @task: task participating in a group stop
352 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
353 * Group stop states are cleared and the group stop count is consumed if
354 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
355 * stop, the appropriate `SIGNAL_*` flags are set.
358 * Must be called with @task->sighand->siglock held.
361 * %true if group stop completion should be notified to the parent, %false
364 static bool task_participate_group_stop(struct task_struct *task)
366 struct signal_struct *sig = task->signal;
367 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
369 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
371 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
376 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
377 sig->group_stop_count--;
380 * Tell the caller to notify completion iff we are entering into a
381 * fresh group stop. Read comment in do_signal_stop() for details.
383 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
384 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
390 void task_join_group_stop(struct task_struct *task)
392 unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
393 struct signal_struct *sig = current->signal;
395 if (sig->group_stop_count) {
396 sig->group_stop_count++;
397 mask |= JOBCTL_STOP_CONSUME;
398 } else if (!(sig->flags & SIGNAL_STOP_STOPPED))
401 /* Have the new thread join an on-going signal group stop */
402 task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
406 * allocate a new signal queue record
407 * - this may be called without locks if and only if t == current, otherwise an
408 * appropriate lock must be held to stop the target task from exiting
410 static struct sigqueue *
411 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
413 struct sigqueue *q = NULL;
414 struct user_struct *user;
418 * Protect access to @t credentials. This can go away when all
419 * callers hold rcu read lock.
421 * NOTE! A pending signal will hold on to the user refcount,
422 * and we get/put the refcount only when the sigpending count
423 * changes from/to zero.
426 user = __task_cred(t)->user;
427 sigpending = atomic_inc_return(&user->sigpending);
432 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
433 q = kmem_cache_alloc(sigqueue_cachep, flags);
435 print_dropped_signal(sig);
438 if (unlikely(q == NULL)) {
439 if (atomic_dec_and_test(&user->sigpending))
442 INIT_LIST_HEAD(&q->list);
450 static void __sigqueue_free(struct sigqueue *q)
452 if (q->flags & SIGQUEUE_PREALLOC)
454 if (atomic_dec_and_test(&q->user->sigpending))
456 kmem_cache_free(sigqueue_cachep, q);
459 void flush_sigqueue(struct sigpending *queue)
463 sigemptyset(&queue->signal);
464 while (!list_empty(&queue->list)) {
465 q = list_entry(queue->list.next, struct sigqueue , list);
466 list_del_init(&q->list);
472 * Flush all pending signals for this kthread.
474 void flush_signals(struct task_struct *t)
478 spin_lock_irqsave(&t->sighand->siglock, flags);
479 clear_tsk_thread_flag(t, TIF_SIGPENDING);
480 flush_sigqueue(&t->pending);
481 flush_sigqueue(&t->signal->shared_pending);
482 spin_unlock_irqrestore(&t->sighand->siglock, flags);
484 EXPORT_SYMBOL(flush_signals);
486 #ifdef CONFIG_POSIX_TIMERS
487 static void __flush_itimer_signals(struct sigpending *pending)
489 sigset_t signal, retain;
490 struct sigqueue *q, *n;
492 signal = pending->signal;
493 sigemptyset(&retain);
495 list_for_each_entry_safe(q, n, &pending->list, list) {
496 int sig = q->info.si_signo;
498 if (likely(q->info.si_code != SI_TIMER)) {
499 sigaddset(&retain, sig);
501 sigdelset(&signal, sig);
502 list_del_init(&q->list);
507 sigorsets(&pending->signal, &signal, &retain);
510 void flush_itimer_signals(void)
512 struct task_struct *tsk = current;
515 spin_lock_irqsave(&tsk->sighand->siglock, flags);
516 __flush_itimer_signals(&tsk->pending);
517 __flush_itimer_signals(&tsk->signal->shared_pending);
518 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
522 void ignore_signals(struct task_struct *t)
526 for (i = 0; i < _NSIG; ++i)
527 t->sighand->action[i].sa.sa_handler = SIG_IGN;
533 * Flush all handlers for a task.
537 flush_signal_handlers(struct task_struct *t, int force_default)
540 struct k_sigaction *ka = &t->sighand->action[0];
541 for (i = _NSIG ; i != 0 ; i--) {
542 if (force_default || ka->sa.sa_handler != SIG_IGN)
543 ka->sa.sa_handler = SIG_DFL;
545 #ifdef __ARCH_HAS_SA_RESTORER
546 ka->sa.sa_restorer = NULL;
548 sigemptyset(&ka->sa.sa_mask);
553 bool unhandled_signal(struct task_struct *tsk, int sig)
555 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
556 if (is_global_init(tsk))
559 if (handler != SIG_IGN && handler != SIG_DFL)
562 /* if ptraced, let the tracer determine */
566 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
569 struct sigqueue *q, *first = NULL;
572 * Collect the siginfo appropriate to this signal. Check if
573 * there is another siginfo for the same signal.
575 list_for_each_entry(q, &list->list, list) {
576 if (q->info.si_signo == sig) {
583 sigdelset(&list->signal, sig);
587 list_del_init(&first->list);
588 copy_siginfo(info, &first->info);
591 (first->flags & SIGQUEUE_PREALLOC) &&
592 (info->si_code == SI_TIMER) &&
593 (info->si_sys_private);
595 __sigqueue_free(first);
598 * Ok, it wasn't in the queue. This must be
599 * a fast-pathed signal or we must have been
600 * out of queue space. So zero out the info.
603 info->si_signo = sig;
605 info->si_code = SI_USER;
611 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
612 kernel_siginfo_t *info, bool *resched_timer)
614 int sig = next_signal(pending, mask);
617 collect_signal(sig, pending, info, resched_timer);
622 * Dequeue a signal and return the element to the caller, which is
623 * expected to free it.
625 * All callers have to hold the siglock.
627 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
629 bool resched_timer = false;
632 /* We only dequeue private signals from ourselves, we don't let
633 * signalfd steal them
635 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
637 signr = __dequeue_signal(&tsk->signal->shared_pending,
638 mask, info, &resched_timer);
639 #ifdef CONFIG_POSIX_TIMERS
643 * itimers are process shared and we restart periodic
644 * itimers in the signal delivery path to prevent DoS
645 * attacks in the high resolution timer case. This is
646 * compliant with the old way of self-restarting
647 * itimers, as the SIGALRM is a legacy signal and only
648 * queued once. Changing the restart behaviour to
649 * restart the timer in the signal dequeue path is
650 * reducing the timer noise on heavy loaded !highres
653 if (unlikely(signr == SIGALRM)) {
654 struct hrtimer *tmr = &tsk->signal->real_timer;
656 if (!hrtimer_is_queued(tmr) &&
657 tsk->signal->it_real_incr != 0) {
658 hrtimer_forward(tmr, tmr->base->get_time(),
659 tsk->signal->it_real_incr);
660 hrtimer_restart(tmr);
670 if (unlikely(sig_kernel_stop(signr))) {
672 * Set a marker that we have dequeued a stop signal. Our
673 * caller might release the siglock and then the pending
674 * stop signal it is about to process is no longer in the
675 * pending bitmasks, but must still be cleared by a SIGCONT
676 * (and overruled by a SIGKILL). So those cases clear this
677 * shared flag after we've set it. Note that this flag may
678 * remain set after the signal we return is ignored or
679 * handled. That doesn't matter because its only purpose
680 * is to alert stop-signal processing code when another
681 * processor has come along and cleared the flag.
683 current->jobctl |= JOBCTL_STOP_DEQUEUED;
685 #ifdef CONFIG_POSIX_TIMERS
688 * Release the siglock to ensure proper locking order
689 * of timer locks outside of siglocks. Note, we leave
690 * irqs disabled here, since the posix-timers code is
691 * about to disable them again anyway.
693 spin_unlock(&tsk->sighand->siglock);
694 posixtimer_rearm(info);
695 spin_lock(&tsk->sighand->siglock);
697 /* Don't expose the si_sys_private value to userspace */
698 info->si_sys_private = 0;
703 EXPORT_SYMBOL_GPL(dequeue_signal);
705 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
707 struct task_struct *tsk = current;
708 struct sigpending *pending = &tsk->pending;
709 struct sigqueue *q, *sync = NULL;
712 * Might a synchronous signal be in the queue?
714 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
718 * Return the first synchronous signal in the queue.
720 list_for_each_entry(q, &pending->list, list) {
721 /* Synchronous signals have a positive si_code */
722 if ((q->info.si_code > SI_USER) &&
723 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
731 * Check if there is another siginfo for the same signal.
733 list_for_each_entry_continue(q, &pending->list, list) {
734 if (q->info.si_signo == sync->info.si_signo)
738 sigdelset(&pending->signal, sync->info.si_signo);
741 list_del_init(&sync->list);
742 copy_siginfo(info, &sync->info);
743 __sigqueue_free(sync);
744 return info->si_signo;
748 * Tell a process that it has a new active signal..
750 * NOTE! we rely on the previous spin_lock to
751 * lock interrupts for us! We can only be called with
752 * "siglock" held, and the local interrupt must
753 * have been disabled when that got acquired!
755 * No need to set need_resched since signal event passing
756 * goes through ->blocked
758 void signal_wake_up_state(struct task_struct *t, unsigned int state)
760 set_tsk_thread_flag(t, TIF_SIGPENDING);
762 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
763 * case. We don't check t->state here because there is a race with it
764 * executing another processor and just now entering stopped state.
765 * By using wake_up_state, we ensure the process will wake up and
766 * handle its death signal.
768 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
773 * Remove signals in mask from the pending set and queue.
774 * Returns 1 if any signals were found.
776 * All callers must be holding the siglock.
778 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
780 struct sigqueue *q, *n;
783 sigandsets(&m, mask, &s->signal);
784 if (sigisemptyset(&m))
787 sigandnsets(&s->signal, &s->signal, mask);
788 list_for_each_entry_safe(q, n, &s->list, list) {
789 if (sigismember(mask, q->info.si_signo)) {
790 list_del_init(&q->list);
796 static inline int is_si_special(const struct kernel_siginfo *info)
798 return info <= SEND_SIG_PRIV;
801 static inline bool si_fromuser(const struct kernel_siginfo *info)
803 return info == SEND_SIG_NOINFO ||
804 (!is_si_special(info) && SI_FROMUSER(info));
808 * called with RCU read lock from check_kill_permission()
810 static bool kill_ok_by_cred(struct task_struct *t)
812 const struct cred *cred = current_cred();
813 const struct cred *tcred = __task_cred(t);
815 return uid_eq(cred->euid, tcred->suid) ||
816 uid_eq(cred->euid, tcred->uid) ||
817 uid_eq(cred->uid, tcred->suid) ||
818 uid_eq(cred->uid, tcred->uid) ||
819 ns_capable(tcred->user_ns, CAP_KILL);
823 * Bad permissions for sending the signal
824 * - the caller must hold the RCU read lock
826 static int check_kill_permission(int sig, struct kernel_siginfo *info,
827 struct task_struct *t)
832 if (!valid_signal(sig))
835 if (!si_fromuser(info))
838 error = audit_signal_info(sig, t); /* Let audit system see the signal */
842 if (!same_thread_group(current, t) &&
843 !kill_ok_by_cred(t)) {
846 sid = task_session(t);
848 * We don't return the error if sid == NULL. The
849 * task was unhashed, the caller must notice this.
851 if (!sid || sid == task_session(current))
859 return security_task_kill(t, info, sig, NULL);
863 * ptrace_trap_notify - schedule trap to notify ptracer
864 * @t: tracee wanting to notify tracer
866 * This function schedules sticky ptrace trap which is cleared on the next
867 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
870 * If @t is running, STOP trap will be taken. If trapped for STOP and
871 * ptracer is listening for events, tracee is woken up so that it can
872 * re-trap for the new event. If trapped otherwise, STOP trap will be
873 * eventually taken without returning to userland after the existing traps
874 * are finished by PTRACE_CONT.
877 * Must be called with @task->sighand->siglock held.
879 static void ptrace_trap_notify(struct task_struct *t)
881 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
882 assert_spin_locked(&t->sighand->siglock);
884 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
885 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
889 * Handle magic process-wide effects of stop/continue signals. Unlike
890 * the signal actions, these happen immediately at signal-generation
891 * time regardless of blocking, ignoring, or handling. This does the
892 * actual continuing for SIGCONT, but not the actual stopping for stop
893 * signals. The process stop is done as a signal action for SIG_DFL.
895 * Returns true if the signal should be actually delivered, otherwise
896 * it should be dropped.
898 static bool prepare_signal(int sig, struct task_struct *p, bool force)
900 struct signal_struct *signal = p->signal;
901 struct task_struct *t;
904 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
905 if (!(signal->flags & SIGNAL_GROUP_EXIT))
906 return sig == SIGKILL;
908 * The process is in the middle of dying, nothing to do.
910 } else if (sig_kernel_stop(sig)) {
912 * This is a stop signal. Remove SIGCONT from all queues.
914 siginitset(&flush, sigmask(SIGCONT));
915 flush_sigqueue_mask(&flush, &signal->shared_pending);
916 for_each_thread(p, t)
917 flush_sigqueue_mask(&flush, &t->pending);
918 } else if (sig == SIGCONT) {
921 * Remove all stop signals from all queues, wake all threads.
923 siginitset(&flush, SIG_KERNEL_STOP_MASK);
924 flush_sigqueue_mask(&flush, &signal->shared_pending);
925 for_each_thread(p, t) {
926 flush_sigqueue_mask(&flush, &t->pending);
927 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
928 if (likely(!(t->ptrace & PT_SEIZED)))
929 wake_up_state(t, __TASK_STOPPED);
931 ptrace_trap_notify(t);
935 * Notify the parent with CLD_CONTINUED if we were stopped.
937 * If we were in the middle of a group stop, we pretend it
938 * was already finished, and then continued. Since SIGCHLD
939 * doesn't queue we report only CLD_STOPPED, as if the next
940 * CLD_CONTINUED was dropped.
943 if (signal->flags & SIGNAL_STOP_STOPPED)
944 why |= SIGNAL_CLD_CONTINUED;
945 else if (signal->group_stop_count)
946 why |= SIGNAL_CLD_STOPPED;
950 * The first thread which returns from do_signal_stop()
951 * will take ->siglock, notice SIGNAL_CLD_MASK, and
952 * notify its parent. See get_signal().
954 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
955 signal->group_stop_count = 0;
956 signal->group_exit_code = 0;
960 return !sig_ignored(p, sig, force);
964 * Test if P wants to take SIG. After we've checked all threads with this,
965 * it's equivalent to finding no threads not blocking SIG. Any threads not
966 * blocking SIG were ruled out because they are not running and already
967 * have pending signals. Such threads will dequeue from the shared queue
968 * as soon as they're available, so putting the signal on the shared queue
969 * will be equivalent to sending it to one such thread.
971 static inline bool wants_signal(int sig, struct task_struct *p)
973 if (sigismember(&p->blocked, sig))
976 if (p->flags & PF_EXITING)
982 if (task_is_stopped_or_traced(p))
985 return task_curr(p) || !task_sigpending(p);
988 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
990 struct signal_struct *signal = p->signal;
991 struct task_struct *t;
994 * Now find a thread we can wake up to take the signal off the queue.
996 * If the main thread wants the signal, it gets first crack.
997 * Probably the least surprising to the average bear.
999 if (wants_signal(sig, p))
1001 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1003 * There is just one thread and it does not need to be woken.
1004 * It will dequeue unblocked signals before it runs again.
1009 * Otherwise try to find a suitable thread.
1011 t = signal->curr_target;
1012 while (!wants_signal(sig, t)) {
1014 if (t == signal->curr_target)
1016 * No thread needs to be woken.
1017 * Any eligible threads will see
1018 * the signal in the queue soon.
1022 signal->curr_target = t;
1026 * Found a killable thread. If the signal will be fatal,
1027 * then start taking the whole group down immediately.
1029 if (sig_fatal(p, sig) &&
1030 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1031 !sigismember(&t->real_blocked, sig) &&
1032 (sig == SIGKILL || !p->ptrace)) {
1034 * This signal will be fatal to the whole group.
1036 if (!sig_kernel_coredump(sig)) {
1038 * Start a group exit and wake everybody up.
1039 * This way we don't have other threads
1040 * running and doing things after a slower
1041 * thread has the fatal signal pending.
1043 signal->flags = SIGNAL_GROUP_EXIT;
1044 signal->group_exit_code = sig;
1045 signal->group_stop_count = 0;
1048 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1049 sigaddset(&t->pending.signal, SIGKILL);
1050 signal_wake_up(t, 1);
1051 } while_each_thread(p, t);
1057 * The signal is already in the shared-pending queue.
1058 * Tell the chosen thread to wake up and dequeue it.
1060 signal_wake_up(t, sig == SIGKILL);
1064 static inline bool legacy_queue(struct sigpending *signals, int sig)
1066 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1069 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1070 enum pid_type type, bool force)
1072 struct sigpending *pending;
1074 int override_rlimit;
1075 int ret = 0, result;
1077 assert_spin_locked(&t->sighand->siglock);
1079 result = TRACE_SIGNAL_IGNORED;
1080 if (!prepare_signal(sig, t, force))
1083 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1085 * Short-circuit ignored signals and support queuing
1086 * exactly one non-rt signal, so that we can get more
1087 * detailed information about the cause of the signal.
1089 result = TRACE_SIGNAL_ALREADY_PENDING;
1090 if (legacy_queue(pending, sig))
1093 result = TRACE_SIGNAL_DELIVERED;
1095 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1097 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1101 * Real-time signals must be queued if sent by sigqueue, or
1102 * some other real-time mechanism. It is implementation
1103 * defined whether kill() does so. We attempt to do so, on
1104 * the principle of least surprise, but since kill is not
1105 * allowed to fail with EAGAIN when low on memory we just
1106 * make sure at least one signal gets delivered and don't
1107 * pass on the info struct.
1110 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1112 override_rlimit = 0;
1114 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
1116 list_add_tail(&q->list, &pending->list);
1117 switch ((unsigned long) info) {
1118 case (unsigned long) SEND_SIG_NOINFO:
1119 clear_siginfo(&q->info);
1120 q->info.si_signo = sig;
1121 q->info.si_errno = 0;
1122 q->info.si_code = SI_USER;
1123 q->info.si_pid = task_tgid_nr_ns(current,
1124 task_active_pid_ns(t));
1127 from_kuid_munged(task_cred_xxx(t, user_ns),
1131 case (unsigned long) SEND_SIG_PRIV:
1132 clear_siginfo(&q->info);
1133 q->info.si_signo = sig;
1134 q->info.si_errno = 0;
1135 q->info.si_code = SI_KERNEL;
1140 copy_siginfo(&q->info, info);
1143 } else if (!is_si_special(info) &&
1144 sig >= SIGRTMIN && info->si_code != SI_USER) {
1146 * Queue overflow, abort. We may abort if the
1147 * signal was rt and sent by user using something
1148 * other than kill().
1150 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1155 * This is a silent loss of information. We still
1156 * send the signal, but the *info bits are lost.
1158 result = TRACE_SIGNAL_LOSE_INFO;
1162 signalfd_notify(t, sig);
1163 sigaddset(&pending->signal, sig);
1165 /* Let multiprocess signals appear after on-going forks */
1166 if (type > PIDTYPE_TGID) {
1167 struct multiprocess_signals *delayed;
1168 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1169 sigset_t *signal = &delayed->signal;
1170 /* Can't queue both a stop and a continue signal */
1172 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1173 else if (sig_kernel_stop(sig))
1174 sigdelset(signal, SIGCONT);
1175 sigaddset(signal, sig);
1179 complete_signal(sig, t, type);
1181 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1185 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1188 switch (siginfo_layout(info->si_signo, info->si_code)) {
1197 case SIL_FAULT_TRAPNO:
1198 case SIL_FAULT_MCEERR:
1199 case SIL_FAULT_BNDERR:
1200 case SIL_FAULT_PKUERR:
1201 case SIL_PERF_EVENT:
1209 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1212 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1215 if (info == SEND_SIG_NOINFO) {
1216 /* Force if sent from an ancestor pid namespace */
1217 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1218 } else if (info == SEND_SIG_PRIV) {
1219 /* Don't ignore kernel generated signals */
1221 } else if (has_si_pid_and_uid(info)) {
1222 /* SIGKILL and SIGSTOP is special or has ids */
1223 struct user_namespace *t_user_ns;
1226 t_user_ns = task_cred_xxx(t, user_ns);
1227 if (current_user_ns() != t_user_ns) {
1228 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1229 info->si_uid = from_kuid_munged(t_user_ns, uid);
1233 /* A kernel generated signal? */
1234 force = (info->si_code == SI_KERNEL);
1236 /* From an ancestor pid namespace? */
1237 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1242 return __send_signal(sig, info, t, type, force);
1245 static void print_fatal_signal(int signr)
1247 struct pt_regs *regs = signal_pt_regs();
1248 pr_info("potentially unexpected fatal signal %d.\n", signr);
1250 #if defined(__i386__) && !defined(__arch_um__)
1251 pr_info("code at %08lx: ", regs->ip);
1254 for (i = 0; i < 16; i++) {
1257 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1259 pr_cont("%02x ", insn);
1269 static int __init setup_print_fatal_signals(char *str)
1271 get_option (&str, &print_fatal_signals);
1276 __setup("print-fatal-signals=", setup_print_fatal_signals);
1279 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1281 return send_signal(sig, info, p, PIDTYPE_TGID);
1284 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1287 unsigned long flags;
1290 if (lock_task_sighand(p, &flags)) {
1291 ret = send_signal(sig, info, p, type);
1292 unlock_task_sighand(p, &flags);
1299 * Force a signal that the process can't ignore: if necessary
1300 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1302 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1303 * since we do not want to have a signal handler that was blocked
1304 * be invoked when user space had explicitly blocked it.
1306 * We don't want to have recursive SIGSEGV's etc, for example,
1307 * that is why we also clear SIGNAL_UNKILLABLE.
1310 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t)
1312 unsigned long int flags;
1313 int ret, blocked, ignored;
1314 struct k_sigaction *action;
1315 int sig = info->si_signo;
1317 spin_lock_irqsave(&t->sighand->siglock, flags);
1318 action = &t->sighand->action[sig-1];
1319 ignored = action->sa.sa_handler == SIG_IGN;
1320 blocked = sigismember(&t->blocked, sig);
1321 if (blocked || ignored) {
1322 action->sa.sa_handler = SIG_DFL;
1324 sigdelset(&t->blocked, sig);
1325 recalc_sigpending_and_wake(t);
1329 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1330 * debugging to leave init killable.
1332 if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
1333 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1334 ret = send_signal(sig, info, t, PIDTYPE_PID);
1335 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1340 int force_sig_info(struct kernel_siginfo *info)
1342 return force_sig_info_to_task(info, current);
1346 * Nuke all other threads in the group.
1348 int zap_other_threads(struct task_struct *p)
1350 struct task_struct *t = p;
1353 p->signal->group_stop_count = 0;
1355 while_each_thread(p, t) {
1356 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1359 /* Don't bother with already dead threads */
1362 sigaddset(&t->pending.signal, SIGKILL);
1363 signal_wake_up(t, 1);
1369 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1370 unsigned long *flags)
1372 struct sighand_struct *sighand;
1376 sighand = rcu_dereference(tsk->sighand);
1377 if (unlikely(sighand == NULL))
1381 * This sighand can be already freed and even reused, but
1382 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1383 * initializes ->siglock: this slab can't go away, it has
1384 * the same object type, ->siglock can't be reinitialized.
1386 * We need to ensure that tsk->sighand is still the same
1387 * after we take the lock, we can race with de_thread() or
1388 * __exit_signal(). In the latter case the next iteration
1389 * must see ->sighand == NULL.
1391 spin_lock_irqsave(&sighand->siglock, *flags);
1392 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1394 spin_unlock_irqrestore(&sighand->siglock, *flags);
1402 * send signal info to all the members of a group
1404 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1405 struct task_struct *p, enum pid_type type)
1410 ret = check_kill_permission(sig, info, p);
1414 ret = do_send_sig_info(sig, info, p, type);
1420 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1421 * control characters do (^C, ^Z etc)
1422 * - the caller must hold at least a readlock on tasklist_lock
1424 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1426 struct task_struct *p = NULL;
1427 int retval, success;
1431 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1432 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1435 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1436 return success ? 0 : retval;
1439 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1442 struct task_struct *p;
1446 p = pid_task(pid, PIDTYPE_PID);
1448 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1450 if (likely(!p || error != -ESRCH))
1454 * The task was unhashed in between, try again. If it
1455 * is dead, pid_task() will return NULL, if we race with
1456 * de_thread() it will find the new leader.
1461 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1465 error = kill_pid_info(sig, info, find_vpid(pid));
1470 static inline bool kill_as_cred_perm(const struct cred *cred,
1471 struct task_struct *target)
1473 const struct cred *pcred = __task_cred(target);
1475 return uid_eq(cred->euid, pcred->suid) ||
1476 uid_eq(cred->euid, pcred->uid) ||
1477 uid_eq(cred->uid, pcred->suid) ||
1478 uid_eq(cred->uid, pcred->uid);
1482 * The usb asyncio usage of siginfo is wrong. The glibc support
1483 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1484 * AKA after the generic fields:
1485 * kernel_pid_t si_pid;
1486 * kernel_uid32_t si_uid;
1487 * sigval_t si_value;
1489 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1490 * after the generic fields is:
1491 * void __user *si_addr;
1493 * This is a practical problem when there is a 64bit big endian kernel
1494 * and a 32bit userspace. As the 32bit address will encoded in the low
1495 * 32bits of the pointer. Those low 32bits will be stored at higher
1496 * address than appear in a 32 bit pointer. So userspace will not
1497 * see the address it was expecting for it's completions.
1499 * There is nothing in the encoding that can allow
1500 * copy_siginfo_to_user32 to detect this confusion of formats, so
1501 * handle this by requiring the caller of kill_pid_usb_asyncio to
1502 * notice when this situration takes place and to store the 32bit
1503 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1506 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1507 struct pid *pid, const struct cred *cred)
1509 struct kernel_siginfo info;
1510 struct task_struct *p;
1511 unsigned long flags;
1514 if (!valid_signal(sig))
1517 clear_siginfo(&info);
1518 info.si_signo = sig;
1519 info.si_errno = errno;
1520 info.si_code = SI_ASYNCIO;
1521 *((sigval_t *)&info.si_pid) = addr;
1524 p = pid_task(pid, PIDTYPE_PID);
1529 if (!kill_as_cred_perm(cred, p)) {
1533 ret = security_task_kill(p, &info, sig, cred);
1538 if (lock_task_sighand(p, &flags)) {
1539 ret = __send_signal(sig, &info, p, PIDTYPE_TGID, false);
1540 unlock_task_sighand(p, &flags);
1548 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1551 * kill_something_info() interprets pid in interesting ways just like kill(2).
1553 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1554 * is probably wrong. Should make it like BSD or SYSV.
1557 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1562 return kill_proc_info(sig, info, pid);
1564 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1568 read_lock(&tasklist_lock);
1570 ret = __kill_pgrp_info(sig, info,
1571 pid ? find_vpid(-pid) : task_pgrp(current));
1573 int retval = 0, count = 0;
1574 struct task_struct * p;
1576 for_each_process(p) {
1577 if (task_pid_vnr(p) > 1 &&
1578 !same_thread_group(p, current)) {
1579 int err = group_send_sig_info(sig, info, p,
1586 ret = count ? retval : -ESRCH;
1588 read_unlock(&tasklist_lock);
1594 * These are for backward compatibility with the rest of the kernel source.
1597 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1600 * Make sure legacy kernel users don't send in bad values
1601 * (normal paths check this in check_kill_permission).
1603 if (!valid_signal(sig))
1606 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1608 EXPORT_SYMBOL(send_sig_info);
1610 #define __si_special(priv) \
1611 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1614 send_sig(int sig, struct task_struct *p, int priv)
1616 return send_sig_info(sig, __si_special(priv), p);
1618 EXPORT_SYMBOL(send_sig);
1620 void force_sig(int sig)
1622 struct kernel_siginfo info;
1624 clear_siginfo(&info);
1625 info.si_signo = sig;
1627 info.si_code = SI_KERNEL;
1630 force_sig_info(&info);
1632 EXPORT_SYMBOL(force_sig);
1635 * When things go south during signal handling, we
1636 * will force a SIGSEGV. And if the signal that caused
1637 * the problem was already a SIGSEGV, we'll want to
1638 * make sure we don't even try to deliver the signal..
1640 void force_sigsegv(int sig)
1642 struct task_struct *p = current;
1644 if (sig == SIGSEGV) {
1645 unsigned long flags;
1646 spin_lock_irqsave(&p->sighand->siglock, flags);
1647 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1648 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1653 int force_sig_fault_to_task(int sig, int code, void __user *addr
1654 ___ARCH_SI_TRAPNO(int trapno)
1655 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1656 , struct task_struct *t)
1658 struct kernel_siginfo info;
1660 clear_siginfo(&info);
1661 info.si_signo = sig;
1663 info.si_code = code;
1664 info.si_addr = addr;
1665 #ifdef __ARCH_SI_TRAPNO
1666 info.si_trapno = trapno;
1670 info.si_flags = flags;
1673 return force_sig_info_to_task(&info, t);
1676 int force_sig_fault(int sig, int code, void __user *addr
1677 ___ARCH_SI_TRAPNO(int trapno)
1678 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1680 return force_sig_fault_to_task(sig, code, addr
1681 ___ARCH_SI_TRAPNO(trapno)
1682 ___ARCH_SI_IA64(imm, flags, isr), current);
1685 int send_sig_fault(int sig, int code, void __user *addr
1686 ___ARCH_SI_TRAPNO(int trapno)
1687 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1688 , struct task_struct *t)
1690 struct kernel_siginfo info;
1692 clear_siginfo(&info);
1693 info.si_signo = sig;
1695 info.si_code = code;
1696 info.si_addr = addr;
1697 #ifdef __ARCH_SI_TRAPNO
1698 info.si_trapno = trapno;
1702 info.si_flags = flags;
1705 return send_sig_info(info.si_signo, &info, t);
1708 int force_sig_mceerr(int code, void __user *addr, short lsb)
1710 struct kernel_siginfo info;
1712 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1713 clear_siginfo(&info);
1714 info.si_signo = SIGBUS;
1716 info.si_code = code;
1717 info.si_addr = addr;
1718 info.si_addr_lsb = lsb;
1719 return force_sig_info(&info);
1722 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1724 struct kernel_siginfo info;
1726 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1727 clear_siginfo(&info);
1728 info.si_signo = SIGBUS;
1730 info.si_code = code;
1731 info.si_addr = addr;
1732 info.si_addr_lsb = lsb;
1733 return send_sig_info(info.si_signo, &info, t);
1735 EXPORT_SYMBOL(send_sig_mceerr);
1737 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1739 struct kernel_siginfo info;
1741 clear_siginfo(&info);
1742 info.si_signo = SIGSEGV;
1744 info.si_code = SEGV_BNDERR;
1745 info.si_addr = addr;
1746 info.si_lower = lower;
1747 info.si_upper = upper;
1748 return force_sig_info(&info);
1752 int force_sig_pkuerr(void __user *addr, u32 pkey)
1754 struct kernel_siginfo info;
1756 clear_siginfo(&info);
1757 info.si_signo = SIGSEGV;
1759 info.si_code = SEGV_PKUERR;
1760 info.si_addr = addr;
1761 info.si_pkey = pkey;
1762 return force_sig_info(&info);
1766 /* For the crazy architectures that include trap information in
1767 * the errno field, instead of an actual errno value.
1769 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1771 struct kernel_siginfo info;
1773 clear_siginfo(&info);
1774 info.si_signo = SIGTRAP;
1775 info.si_errno = errno;
1776 info.si_code = TRAP_HWBKPT;
1777 info.si_addr = addr;
1778 return force_sig_info(&info);
1781 int kill_pgrp(struct pid *pid, int sig, int priv)
1785 read_lock(&tasklist_lock);
1786 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1787 read_unlock(&tasklist_lock);
1791 EXPORT_SYMBOL(kill_pgrp);
1793 int kill_pid(struct pid *pid, int sig, int priv)
1795 return kill_pid_info(sig, __si_special(priv), pid);
1797 EXPORT_SYMBOL(kill_pid);
1800 * These functions support sending signals using preallocated sigqueue
1801 * structures. This is needed "because realtime applications cannot
1802 * afford to lose notifications of asynchronous events, like timer
1803 * expirations or I/O completions". In the case of POSIX Timers
1804 * we allocate the sigqueue structure from the timer_create. If this
1805 * allocation fails we are able to report the failure to the application
1806 * with an EAGAIN error.
1808 struct sigqueue *sigqueue_alloc(void)
1810 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1813 q->flags |= SIGQUEUE_PREALLOC;
1818 void sigqueue_free(struct sigqueue *q)
1820 unsigned long flags;
1821 spinlock_t *lock = ¤t->sighand->siglock;
1823 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1825 * We must hold ->siglock while testing q->list
1826 * to serialize with collect_signal() or with
1827 * __exit_signal()->flush_sigqueue().
1829 spin_lock_irqsave(lock, flags);
1830 q->flags &= ~SIGQUEUE_PREALLOC;
1832 * If it is queued it will be freed when dequeued,
1833 * like the "regular" sigqueue.
1835 if (!list_empty(&q->list))
1837 spin_unlock_irqrestore(lock, flags);
1843 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1845 int sig = q->info.si_signo;
1846 struct sigpending *pending;
1847 struct task_struct *t;
1848 unsigned long flags;
1851 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1855 t = pid_task(pid, type);
1856 if (!t || !likely(lock_task_sighand(t, &flags)))
1859 ret = 1; /* the signal is ignored */
1860 result = TRACE_SIGNAL_IGNORED;
1861 if (!prepare_signal(sig, t, false))
1865 if (unlikely(!list_empty(&q->list))) {
1867 * If an SI_TIMER entry is already queue just increment
1868 * the overrun count.
1870 BUG_ON(q->info.si_code != SI_TIMER);
1871 q->info.si_overrun++;
1872 result = TRACE_SIGNAL_ALREADY_PENDING;
1875 q->info.si_overrun = 0;
1877 signalfd_notify(t, sig);
1878 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1879 list_add_tail(&q->list, &pending->list);
1880 sigaddset(&pending->signal, sig);
1881 complete_signal(sig, t, type);
1882 result = TRACE_SIGNAL_DELIVERED;
1884 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
1885 unlock_task_sighand(t, &flags);
1891 static void do_notify_pidfd(struct task_struct *task)
1895 WARN_ON(task->exit_state == 0);
1896 pid = task_pid(task);
1897 wake_up_all(&pid->wait_pidfd);
1901 * Let a parent know about the death of a child.
1902 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1904 * Returns true if our parent ignored us and so we've switched to
1907 bool do_notify_parent(struct task_struct *tsk, int sig)
1909 struct kernel_siginfo info;
1910 unsigned long flags;
1911 struct sighand_struct *psig;
1912 bool autoreap = false;
1917 /* do_notify_parent_cldstop should have been called instead. */
1918 BUG_ON(task_is_stopped_or_traced(tsk));
1920 BUG_ON(!tsk->ptrace &&
1921 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1923 /* Wake up all pidfd waiters */
1924 do_notify_pidfd(tsk);
1926 if (sig != SIGCHLD) {
1928 * This is only possible if parent == real_parent.
1929 * Check if it has changed security domain.
1931 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
1935 clear_siginfo(&info);
1936 info.si_signo = sig;
1939 * We are under tasklist_lock here so our parent is tied to
1940 * us and cannot change.
1942 * task_active_pid_ns will always return the same pid namespace
1943 * until a task passes through release_task.
1945 * write_lock() currently calls preempt_disable() which is the
1946 * same as rcu_read_lock(), but according to Oleg, this is not
1947 * correct to rely on this
1950 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1951 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1955 task_cputime(tsk, &utime, &stime);
1956 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
1957 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
1959 info.si_status = tsk->exit_code & 0x7f;
1960 if (tsk->exit_code & 0x80)
1961 info.si_code = CLD_DUMPED;
1962 else if (tsk->exit_code & 0x7f)
1963 info.si_code = CLD_KILLED;
1965 info.si_code = CLD_EXITED;
1966 info.si_status = tsk->exit_code >> 8;
1969 psig = tsk->parent->sighand;
1970 spin_lock_irqsave(&psig->siglock, flags);
1971 if (!tsk->ptrace && sig == SIGCHLD &&
1972 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1973 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1975 * We are exiting and our parent doesn't care. POSIX.1
1976 * defines special semantics for setting SIGCHLD to SIG_IGN
1977 * or setting the SA_NOCLDWAIT flag: we should be reaped
1978 * automatically and not left for our parent's wait4 call.
1979 * Rather than having the parent do it as a magic kind of
1980 * signal handler, we just set this to tell do_exit that we
1981 * can be cleaned up without becoming a zombie. Note that
1982 * we still call __wake_up_parent in this case, because a
1983 * blocked sys_wait4 might now return -ECHILD.
1985 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1986 * is implementation-defined: we do (if you don't want
1987 * it, just use SIG_IGN instead).
1990 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1994 * Send with __send_signal as si_pid and si_uid are in the
1995 * parent's namespaces.
1997 if (valid_signal(sig) && sig)
1998 __send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false);
1999 __wake_up_parent(tsk, tsk->parent);
2000 spin_unlock_irqrestore(&psig->siglock, flags);
2006 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2007 * @tsk: task reporting the state change
2008 * @for_ptracer: the notification is for ptracer
2009 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2011 * Notify @tsk's parent that the stopped/continued state has changed. If
2012 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2013 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2016 * Must be called with tasklist_lock at least read locked.
2018 static void do_notify_parent_cldstop(struct task_struct *tsk,
2019 bool for_ptracer, int why)
2021 struct kernel_siginfo info;
2022 unsigned long flags;
2023 struct task_struct *parent;
2024 struct sighand_struct *sighand;
2028 parent = tsk->parent;
2030 tsk = tsk->group_leader;
2031 parent = tsk->real_parent;
2034 clear_siginfo(&info);
2035 info.si_signo = SIGCHLD;
2038 * see comment in do_notify_parent() about the following 4 lines
2041 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2042 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2045 task_cputime(tsk, &utime, &stime);
2046 info.si_utime = nsec_to_clock_t(utime);
2047 info.si_stime = nsec_to_clock_t(stime);
2052 info.si_status = SIGCONT;
2055 info.si_status = tsk->signal->group_exit_code & 0x7f;
2058 info.si_status = tsk->exit_code & 0x7f;
2064 sighand = parent->sighand;
2065 spin_lock_irqsave(&sighand->siglock, flags);
2066 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2067 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2068 __group_send_sig_info(SIGCHLD, &info, parent);
2070 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2072 __wake_up_parent(tsk, parent);
2073 spin_unlock_irqrestore(&sighand->siglock, flags);
2076 static inline bool may_ptrace_stop(void)
2078 if (!likely(current->ptrace))
2081 * Are we in the middle of do_coredump?
2082 * If so and our tracer is also part of the coredump stopping
2083 * is a deadlock situation, and pointless because our tracer
2084 * is dead so don't allow us to stop.
2085 * If SIGKILL was already sent before the caller unlocked
2086 * ->siglock we must see ->core_state != NULL. Otherwise it
2087 * is safe to enter schedule().
2089 * This is almost outdated, a task with the pending SIGKILL can't
2090 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2091 * after SIGKILL was already dequeued.
2093 if (unlikely(current->mm->core_state) &&
2094 unlikely(current->mm == current->parent->mm))
2101 * Return non-zero if there is a SIGKILL that should be waking us up.
2102 * Called with the siglock held.
2104 static bool sigkill_pending(struct task_struct *tsk)
2106 return sigismember(&tsk->pending.signal, SIGKILL) ||
2107 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
2111 * This must be called with current->sighand->siglock held.
2113 * This should be the path for all ptrace stops.
2114 * We always set current->last_siginfo while stopped here.
2115 * That makes it a way to test a stopped process for
2116 * being ptrace-stopped vs being job-control-stopped.
2118 * If we actually decide not to stop at all because the tracer
2119 * is gone, we keep current->exit_code unless clear_code.
2121 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2122 __releases(¤t->sighand->siglock)
2123 __acquires(¤t->sighand->siglock)
2125 bool gstop_done = false;
2127 if (arch_ptrace_stop_needed(exit_code, info)) {
2129 * The arch code has something special to do before a
2130 * ptrace stop. This is allowed to block, e.g. for faults
2131 * on user stack pages. We can't keep the siglock while
2132 * calling arch_ptrace_stop, so we must release it now.
2133 * To preserve proper semantics, we must do this before
2134 * any signal bookkeeping like checking group_stop_count.
2135 * Meanwhile, a SIGKILL could come in before we retake the
2136 * siglock. That must prevent us from sleeping in TASK_TRACED.
2137 * So after regaining the lock, we must check for SIGKILL.
2139 spin_unlock_irq(¤t->sighand->siglock);
2140 arch_ptrace_stop(exit_code, info);
2141 spin_lock_irq(¤t->sighand->siglock);
2142 if (sigkill_pending(current))
2146 set_special_state(TASK_TRACED);
2149 * We're committing to trapping. TRACED should be visible before
2150 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2151 * Also, transition to TRACED and updates to ->jobctl should be
2152 * atomic with respect to siglock and should be done after the arch
2153 * hook as siglock is released and regrabbed across it.
2158 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2160 * set_current_state() smp_wmb();
2162 * wait_task_stopped()
2163 * task_stopped_code()
2164 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2168 current->last_siginfo = info;
2169 current->exit_code = exit_code;
2172 * If @why is CLD_STOPPED, we're trapping to participate in a group
2173 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2174 * across siglock relocks since INTERRUPT was scheduled, PENDING
2175 * could be clear now. We act as if SIGCONT is received after
2176 * TASK_TRACED is entered - ignore it.
2178 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2179 gstop_done = task_participate_group_stop(current);
2181 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2182 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2183 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2184 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2186 /* entering a trap, clear TRAPPING */
2187 task_clear_jobctl_trapping(current);
2189 spin_unlock_irq(¤t->sighand->siglock);
2190 read_lock(&tasklist_lock);
2191 if (may_ptrace_stop()) {
2193 * Notify parents of the stop.
2195 * While ptraced, there are two parents - the ptracer and
2196 * the real_parent of the group_leader. The ptracer should
2197 * know about every stop while the real parent is only
2198 * interested in the completion of group stop. The states
2199 * for the two don't interact with each other. Notify
2200 * separately unless they're gonna be duplicates.
2202 do_notify_parent_cldstop(current, true, why);
2203 if (gstop_done && ptrace_reparented(current))
2204 do_notify_parent_cldstop(current, false, why);
2207 * Don't want to allow preemption here, because
2208 * sys_ptrace() needs this task to be inactive.
2210 * XXX: implement read_unlock_no_resched().
2213 read_unlock(&tasklist_lock);
2214 cgroup_enter_frozen();
2215 preempt_enable_no_resched();
2216 freezable_schedule();
2217 cgroup_leave_frozen(true);
2220 * By the time we got the lock, our tracer went away.
2221 * Don't drop the lock yet, another tracer may come.
2223 * If @gstop_done, the ptracer went away between group stop
2224 * completion and here. During detach, it would have set
2225 * JOBCTL_STOP_PENDING on us and we'll re-enter
2226 * TASK_STOPPED in do_signal_stop() on return, so notifying
2227 * the real parent of the group stop completion is enough.
2230 do_notify_parent_cldstop(current, false, why);
2232 /* tasklist protects us from ptrace_freeze_traced() */
2233 __set_current_state(TASK_RUNNING);
2235 current->exit_code = 0;
2236 read_unlock(&tasklist_lock);
2240 * We are back. Now reacquire the siglock before touching
2241 * last_siginfo, so that we are sure to have synchronized with
2242 * any signal-sending on another CPU that wants to examine it.
2244 spin_lock_irq(¤t->sighand->siglock);
2245 current->last_siginfo = NULL;
2247 /* LISTENING can be set only during STOP traps, clear it */
2248 current->jobctl &= ~JOBCTL_LISTENING;
2251 * Queued signals ignored us while we were stopped for tracing.
2252 * So check for any that we should take before resuming user mode.
2253 * This sets TIF_SIGPENDING, but never clears it.
2255 recalc_sigpending_tsk(current);
2258 static void ptrace_do_notify(int signr, int exit_code, int why)
2260 kernel_siginfo_t info;
2262 clear_siginfo(&info);
2263 info.si_signo = signr;
2264 info.si_code = exit_code;
2265 info.si_pid = task_pid_vnr(current);
2266 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2268 /* Let the debugger run. */
2269 ptrace_stop(exit_code, why, 1, &info);
2272 void ptrace_notify(int exit_code)
2274 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2275 if (unlikely(current->task_works))
2278 spin_lock_irq(¤t->sighand->siglock);
2279 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2280 spin_unlock_irq(¤t->sighand->siglock);
2284 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2285 * @signr: signr causing group stop if initiating
2287 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2288 * and participate in it. If already set, participate in the existing
2289 * group stop. If participated in a group stop (and thus slept), %true is
2290 * returned with siglock released.
2292 * If ptraced, this function doesn't handle stop itself. Instead,
2293 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2294 * untouched. The caller must ensure that INTERRUPT trap handling takes
2295 * places afterwards.
2298 * Must be called with @current->sighand->siglock held, which is released
2302 * %false if group stop is already cancelled or ptrace trap is scheduled.
2303 * %true if participated in group stop.
2305 static bool do_signal_stop(int signr)
2306 __releases(¤t->sighand->siglock)
2308 struct signal_struct *sig = current->signal;
2310 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2311 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2312 struct task_struct *t;
2314 /* signr will be recorded in task->jobctl for retries */
2315 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2317 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2318 unlikely(signal_group_exit(sig)))
2321 * There is no group stop already in progress. We must
2324 * While ptraced, a task may be resumed while group stop is
2325 * still in effect and then receive a stop signal and
2326 * initiate another group stop. This deviates from the
2327 * usual behavior as two consecutive stop signals can't
2328 * cause two group stops when !ptraced. That is why we
2329 * also check !task_is_stopped(t) below.
2331 * The condition can be distinguished by testing whether
2332 * SIGNAL_STOP_STOPPED is already set. Don't generate
2333 * group_exit_code in such case.
2335 * This is not necessary for SIGNAL_STOP_CONTINUED because
2336 * an intervening stop signal is required to cause two
2337 * continued events regardless of ptrace.
2339 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2340 sig->group_exit_code = signr;
2342 sig->group_stop_count = 0;
2344 if (task_set_jobctl_pending(current, signr | gstop))
2345 sig->group_stop_count++;
2348 while_each_thread(current, t) {
2350 * Setting state to TASK_STOPPED for a group
2351 * stop is always done with the siglock held,
2352 * so this check has no races.
2354 if (!task_is_stopped(t) &&
2355 task_set_jobctl_pending(t, signr | gstop)) {
2356 sig->group_stop_count++;
2357 if (likely(!(t->ptrace & PT_SEIZED)))
2358 signal_wake_up(t, 0);
2360 ptrace_trap_notify(t);
2365 if (likely(!current->ptrace)) {
2369 * If there are no other threads in the group, or if there
2370 * is a group stop in progress and we are the last to stop,
2371 * report to the parent.
2373 if (task_participate_group_stop(current))
2374 notify = CLD_STOPPED;
2376 set_special_state(TASK_STOPPED);
2377 spin_unlock_irq(¤t->sighand->siglock);
2380 * Notify the parent of the group stop completion. Because
2381 * we're not holding either the siglock or tasklist_lock
2382 * here, ptracer may attach inbetween; however, this is for
2383 * group stop and should always be delivered to the real
2384 * parent of the group leader. The new ptracer will get
2385 * its notification when this task transitions into
2389 read_lock(&tasklist_lock);
2390 do_notify_parent_cldstop(current, false, notify);
2391 read_unlock(&tasklist_lock);
2394 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2395 cgroup_enter_frozen();
2396 freezable_schedule();
2400 * While ptraced, group stop is handled by STOP trap.
2401 * Schedule it and let the caller deal with it.
2403 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2409 * do_jobctl_trap - take care of ptrace jobctl traps
2411 * When PT_SEIZED, it's used for both group stop and explicit
2412 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2413 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2414 * the stop signal; otherwise, %SIGTRAP.
2416 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2417 * number as exit_code and no siginfo.
2420 * Must be called with @current->sighand->siglock held, which may be
2421 * released and re-acquired before returning with intervening sleep.
2423 static void do_jobctl_trap(void)
2425 struct signal_struct *signal = current->signal;
2426 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2428 if (current->ptrace & PT_SEIZED) {
2429 if (!signal->group_stop_count &&
2430 !(signal->flags & SIGNAL_STOP_STOPPED))
2432 WARN_ON_ONCE(!signr);
2433 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2436 WARN_ON_ONCE(!signr);
2437 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2438 current->exit_code = 0;
2443 * do_freezer_trap - handle the freezer jobctl trap
2445 * Puts the task into frozen state, if only the task is not about to quit.
2446 * In this case it drops JOBCTL_TRAP_FREEZE.
2449 * Must be called with @current->sighand->siglock held,
2450 * which is always released before returning.
2452 static void do_freezer_trap(void)
2453 __releases(¤t->sighand->siglock)
2456 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2457 * let's make another loop to give it a chance to be handled.
2458 * In any case, we'll return back.
2460 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2461 JOBCTL_TRAP_FREEZE) {
2462 spin_unlock_irq(¤t->sighand->siglock);
2467 * Now we're sure that there is no pending fatal signal and no
2468 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2469 * immediately (if there is a non-fatal signal pending), and
2470 * put the task into sleep.
2472 __set_current_state(TASK_INTERRUPTIBLE);
2473 clear_thread_flag(TIF_SIGPENDING);
2474 spin_unlock_irq(¤t->sighand->siglock);
2475 cgroup_enter_frozen();
2476 freezable_schedule();
2479 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2482 * We do not check sig_kernel_stop(signr) but set this marker
2483 * unconditionally because we do not know whether debugger will
2484 * change signr. This flag has no meaning unless we are going
2485 * to stop after return from ptrace_stop(). In this case it will
2486 * be checked in do_signal_stop(), we should only stop if it was
2487 * not cleared by SIGCONT while we were sleeping. See also the
2488 * comment in dequeue_signal().
2490 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2491 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2493 /* We're back. Did the debugger cancel the sig? */
2494 signr = current->exit_code;
2498 current->exit_code = 0;
2501 * Update the siginfo structure if the signal has
2502 * changed. If the debugger wanted something
2503 * specific in the siginfo structure then it should
2504 * have updated *info via PTRACE_SETSIGINFO.
2506 if (signr != info->si_signo) {
2507 clear_siginfo(info);
2508 info->si_signo = signr;
2510 info->si_code = SI_USER;
2512 info->si_pid = task_pid_vnr(current->parent);
2513 info->si_uid = from_kuid_munged(current_user_ns(),
2514 task_uid(current->parent));
2518 /* If the (new) signal is now blocked, requeue it. */
2519 if (sigismember(¤t->blocked, signr)) {
2520 send_signal(signr, info, current, PIDTYPE_PID);
2527 static void hide_si_addr_tag_bits(struct ksignal *ksig)
2529 switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
2531 case SIL_FAULT_TRAPNO:
2532 case SIL_FAULT_MCEERR:
2533 case SIL_FAULT_BNDERR:
2534 case SIL_FAULT_PKUERR:
2535 case SIL_PERF_EVENT:
2536 ksig->info.si_addr = arch_untagged_si_addr(
2537 ksig->info.si_addr, ksig->sig, ksig->info.si_code);
2549 bool get_signal(struct ksignal *ksig)
2551 struct sighand_struct *sighand = current->sighand;
2552 struct signal_struct *signal = current->signal;
2555 if (unlikely(current->task_works))
2559 * For non-generic architectures, check for TIF_NOTIFY_SIGNAL so
2560 * that the arch handlers don't all have to do it. If we get here
2561 * without TIF_SIGPENDING, just exit after running signal work.
2563 if (!IS_ENABLED(CONFIG_GENERIC_ENTRY)) {
2564 if (test_thread_flag(TIF_NOTIFY_SIGNAL))
2565 tracehook_notify_signal();
2566 if (!task_sigpending(current))
2570 if (unlikely(uprobe_deny_signal()))
2574 * Do this once, we can't return to user-mode if freezing() == T.
2575 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2576 * thus do not need another check after return.
2581 spin_lock_irq(&sighand->siglock);
2584 * Every stopped thread goes here after wakeup. Check to see if
2585 * we should notify the parent, prepare_signal(SIGCONT) encodes
2586 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2588 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2591 if (signal->flags & SIGNAL_CLD_CONTINUED)
2592 why = CLD_CONTINUED;
2596 signal->flags &= ~SIGNAL_CLD_MASK;
2598 spin_unlock_irq(&sighand->siglock);
2601 * Notify the parent that we're continuing. This event is
2602 * always per-process and doesn't make whole lot of sense
2603 * for ptracers, who shouldn't consume the state via
2604 * wait(2) either, but, for backward compatibility, notify
2605 * the ptracer of the group leader too unless it's gonna be
2608 read_lock(&tasklist_lock);
2609 do_notify_parent_cldstop(current, false, why);
2611 if (ptrace_reparented(current->group_leader))
2612 do_notify_parent_cldstop(current->group_leader,
2614 read_unlock(&tasklist_lock);
2619 /* Has this task already been marked for death? */
2620 if (signal_group_exit(signal)) {
2621 ksig->info.si_signo = signr = SIGKILL;
2622 sigdelset(¤t->pending.signal, SIGKILL);
2623 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2624 &sighand->action[SIGKILL - 1]);
2625 recalc_sigpending();
2630 struct k_sigaction *ka;
2632 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2636 if (unlikely(current->jobctl &
2637 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2638 if (current->jobctl & JOBCTL_TRAP_MASK) {
2640 spin_unlock_irq(&sighand->siglock);
2641 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2648 * If the task is leaving the frozen state, let's update
2649 * cgroup counters and reset the frozen bit.
2651 if (unlikely(cgroup_task_frozen(current))) {
2652 spin_unlock_irq(&sighand->siglock);
2653 cgroup_leave_frozen(false);
2658 * Signals generated by the execution of an instruction
2659 * need to be delivered before any other pending signals
2660 * so that the instruction pointer in the signal stack
2661 * frame points to the faulting instruction.
2663 signr = dequeue_synchronous_signal(&ksig->info);
2665 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2668 break; /* will return 0 */
2670 if (unlikely(current->ptrace) && signr != SIGKILL) {
2671 signr = ptrace_signal(signr, &ksig->info);
2676 ka = &sighand->action[signr-1];
2678 /* Trace actually delivered signals. */
2679 trace_signal_deliver(signr, &ksig->info, ka);
2681 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2683 if (ka->sa.sa_handler != SIG_DFL) {
2684 /* Run the handler. */
2687 if (ka->sa.sa_flags & SA_ONESHOT)
2688 ka->sa.sa_handler = SIG_DFL;
2690 break; /* will return non-zero "signr" value */
2694 * Now we are doing the default action for this signal.
2696 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2700 * Global init gets no signals it doesn't want.
2701 * Container-init gets no signals it doesn't want from same
2704 * Note that if global/container-init sees a sig_kernel_only()
2705 * signal here, the signal must have been generated internally
2706 * or must have come from an ancestor namespace. In either
2707 * case, the signal cannot be dropped.
2709 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2710 !sig_kernel_only(signr))
2713 if (sig_kernel_stop(signr)) {
2715 * The default action is to stop all threads in
2716 * the thread group. The job control signals
2717 * do nothing in an orphaned pgrp, but SIGSTOP
2718 * always works. Note that siglock needs to be
2719 * dropped during the call to is_orphaned_pgrp()
2720 * because of lock ordering with tasklist_lock.
2721 * This allows an intervening SIGCONT to be posted.
2722 * We need to check for that and bail out if necessary.
2724 if (signr != SIGSTOP) {
2725 spin_unlock_irq(&sighand->siglock);
2727 /* signals can be posted during this window */
2729 if (is_current_pgrp_orphaned())
2732 spin_lock_irq(&sighand->siglock);
2735 if (likely(do_signal_stop(ksig->info.si_signo))) {
2736 /* It released the siglock. */
2741 * We didn't actually stop, due to a race
2742 * with SIGCONT or something like that.
2748 spin_unlock_irq(&sighand->siglock);
2749 if (unlikely(cgroup_task_frozen(current)))
2750 cgroup_leave_frozen(true);
2753 * Anything else is fatal, maybe with a core dump.
2755 current->flags |= PF_SIGNALED;
2757 if (sig_kernel_coredump(signr)) {
2758 if (print_fatal_signals)
2759 print_fatal_signal(ksig->info.si_signo);
2760 proc_coredump_connector(current);
2762 * If it was able to dump core, this kills all
2763 * other threads in the group and synchronizes with
2764 * their demise. If we lost the race with another
2765 * thread getting here, it set group_exit_code
2766 * first and our do_group_exit call below will use
2767 * that value and ignore the one we pass it.
2769 do_coredump(&ksig->info);
2773 * PF_IO_WORKER threads will catch and exit on fatal signals
2774 * themselves. They have cleanup that must be performed, so
2775 * we cannot call do_exit() on their behalf.
2777 if (current->flags & PF_IO_WORKER)
2781 * Death signals, no core dump.
2783 do_group_exit(ksig->info.si_signo);
2786 spin_unlock_irq(&sighand->siglock);
2790 if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
2791 hide_si_addr_tag_bits(ksig);
2793 return ksig->sig > 0;
2797 * signal_delivered -
2798 * @ksig: kernel signal struct
2799 * @stepping: nonzero if debugger single-step or block-step in use
2801 * This function should be called when a signal has successfully been
2802 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2803 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2804 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2806 static void signal_delivered(struct ksignal *ksig, int stepping)
2810 /* A signal was successfully delivered, and the
2811 saved sigmask was stored on the signal frame,
2812 and will be restored by sigreturn. So we can
2813 simply clear the restore sigmask flag. */
2814 clear_restore_sigmask();
2816 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2817 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2818 sigaddset(&blocked, ksig->sig);
2819 set_current_blocked(&blocked);
2820 tracehook_signal_handler(stepping);
2823 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2826 force_sigsegv(ksig->sig);
2828 signal_delivered(ksig, stepping);
2832 * It could be that complete_signal() picked us to notify about the
2833 * group-wide signal. Other threads should be notified now to take
2834 * the shared signals in @which since we will not.
2836 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2839 struct task_struct *t;
2841 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2842 if (sigisemptyset(&retarget))
2846 while_each_thread(tsk, t) {
2847 if (t->flags & PF_EXITING)
2850 if (!has_pending_signals(&retarget, &t->blocked))
2852 /* Remove the signals this thread can handle. */
2853 sigandsets(&retarget, &retarget, &t->blocked);
2855 if (!task_sigpending(t))
2856 signal_wake_up(t, 0);
2858 if (sigisemptyset(&retarget))
2863 void exit_signals(struct task_struct *tsk)
2869 * @tsk is about to have PF_EXITING set - lock out users which
2870 * expect stable threadgroup.
2872 cgroup_threadgroup_change_begin(tsk);
2874 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2875 tsk->flags |= PF_EXITING;
2876 cgroup_threadgroup_change_end(tsk);
2880 spin_lock_irq(&tsk->sighand->siglock);
2882 * From now this task is not visible for group-wide signals,
2883 * see wants_signal(), do_signal_stop().
2885 tsk->flags |= PF_EXITING;
2887 cgroup_threadgroup_change_end(tsk);
2889 if (!task_sigpending(tsk))
2892 unblocked = tsk->blocked;
2893 signotset(&unblocked);
2894 retarget_shared_pending(tsk, &unblocked);
2896 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2897 task_participate_group_stop(tsk))
2898 group_stop = CLD_STOPPED;
2900 spin_unlock_irq(&tsk->sighand->siglock);
2903 * If group stop has completed, deliver the notification. This
2904 * should always go to the real parent of the group leader.
2906 if (unlikely(group_stop)) {
2907 read_lock(&tasklist_lock);
2908 do_notify_parent_cldstop(tsk, false, group_stop);
2909 read_unlock(&tasklist_lock);
2914 * System call entry points.
2918 * sys_restart_syscall - restart a system call
2920 SYSCALL_DEFINE0(restart_syscall)
2922 struct restart_block *restart = ¤t->restart_block;
2923 return restart->fn(restart);
2926 long do_no_restart_syscall(struct restart_block *param)
2931 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2933 if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
2934 sigset_t newblocked;
2935 /* A set of now blocked but previously unblocked signals. */
2936 sigandnsets(&newblocked, newset, ¤t->blocked);
2937 retarget_shared_pending(tsk, &newblocked);
2939 tsk->blocked = *newset;
2940 recalc_sigpending();
2944 * set_current_blocked - change current->blocked mask
2947 * It is wrong to change ->blocked directly, this helper should be used
2948 * to ensure the process can't miss a shared signal we are going to block.
2950 void set_current_blocked(sigset_t *newset)
2952 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2953 __set_current_blocked(newset);
2956 void __set_current_blocked(const sigset_t *newset)
2958 struct task_struct *tsk = current;
2961 * In case the signal mask hasn't changed, there is nothing we need
2962 * to do. The current->blocked shouldn't be modified by other task.
2964 if (sigequalsets(&tsk->blocked, newset))
2967 spin_lock_irq(&tsk->sighand->siglock);
2968 __set_task_blocked(tsk, newset);
2969 spin_unlock_irq(&tsk->sighand->siglock);
2973 * This is also useful for kernel threads that want to temporarily
2974 * (or permanently) block certain signals.
2976 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2977 * interface happily blocks "unblockable" signals like SIGKILL
2980 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2982 struct task_struct *tsk = current;
2985 /* Lockless, only current can change ->blocked, never from irq */
2987 *oldset = tsk->blocked;
2991 sigorsets(&newset, &tsk->blocked, set);
2994 sigandnsets(&newset, &tsk->blocked, set);
3003 __set_current_blocked(&newset);
3006 EXPORT_SYMBOL(sigprocmask);
3009 * The api helps set app-provided sigmasks.
3011 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
3012 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
3014 * Note that it does set_restore_sigmask() in advance, so it must be always
3015 * paired with restore_saved_sigmask_unless() before return from syscall.
3017 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
3023 if (sigsetsize != sizeof(sigset_t))
3025 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
3028 set_restore_sigmask();
3029 current->saved_sigmask = current->blocked;
3030 set_current_blocked(&kmask);
3035 #ifdef CONFIG_COMPAT
3036 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3043 if (sigsetsize != sizeof(compat_sigset_t))
3045 if (get_compat_sigset(&kmask, umask))
3048 set_restore_sigmask();
3049 current->saved_sigmask = current->blocked;
3050 set_current_blocked(&kmask);
3057 * sys_rt_sigprocmask - change the list of currently blocked signals
3058 * @how: whether to add, remove, or set signals
3059 * @nset: stores pending signals
3060 * @oset: previous value of signal mask if non-null
3061 * @sigsetsize: size of sigset_t type
3063 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3064 sigset_t __user *, oset, size_t, sigsetsize)
3066 sigset_t old_set, new_set;
3069 /* XXX: Don't preclude handling different sized sigset_t's. */
3070 if (sigsetsize != sizeof(sigset_t))
3073 old_set = current->blocked;
3076 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3078 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3080 error = sigprocmask(how, &new_set, NULL);
3086 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3093 #ifdef CONFIG_COMPAT
3094 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3095 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3097 sigset_t old_set = current->blocked;
3099 /* XXX: Don't preclude handling different sized sigset_t's. */
3100 if (sigsetsize != sizeof(sigset_t))
3106 if (get_compat_sigset(&new_set, nset))
3108 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3110 error = sigprocmask(how, &new_set, NULL);
3114 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3118 static void do_sigpending(sigset_t *set)
3120 spin_lock_irq(¤t->sighand->siglock);
3121 sigorsets(set, ¤t->pending.signal,
3122 ¤t->signal->shared_pending.signal);
3123 spin_unlock_irq(¤t->sighand->siglock);
3125 /* Outside the lock because only this thread touches it. */
3126 sigandsets(set, ¤t->blocked, set);
3130 * sys_rt_sigpending - examine a pending signal that has been raised
3132 * @uset: stores pending signals
3133 * @sigsetsize: size of sigset_t type or larger
3135 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3139 if (sigsetsize > sizeof(*uset))
3142 do_sigpending(&set);
3144 if (copy_to_user(uset, &set, sigsetsize))
3150 #ifdef CONFIG_COMPAT
3151 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3152 compat_size_t, sigsetsize)
3156 if (sigsetsize > sizeof(*uset))
3159 do_sigpending(&set);
3161 return put_compat_sigset(uset, &set, sigsetsize);
3165 static const struct {
3166 unsigned char limit, layout;
3168 [SIGILL] = { NSIGILL, SIL_FAULT },
3169 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3170 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3171 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3172 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3174 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3176 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3177 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3178 [SIGSYS] = { NSIGSYS, SIL_SYS },
3181 static bool known_siginfo_layout(unsigned sig, int si_code)
3183 if (si_code == SI_KERNEL)
3185 else if ((si_code > SI_USER)) {
3186 if (sig_specific_sicodes(sig)) {
3187 if (si_code <= sig_sicodes[sig].limit)
3190 else if (si_code <= NSIGPOLL)
3193 else if (si_code >= SI_DETHREAD)
3195 else if (si_code == SI_ASYNCNL)
3200 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3202 enum siginfo_layout layout = SIL_KILL;
3203 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3204 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3205 (si_code <= sig_sicodes[sig].limit)) {
3206 layout = sig_sicodes[sig].layout;
3207 /* Handle the exceptions */
3208 if ((sig == SIGBUS) &&
3209 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3210 layout = SIL_FAULT_MCEERR;
3211 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3212 layout = SIL_FAULT_BNDERR;
3214 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3215 layout = SIL_FAULT_PKUERR;
3217 else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
3218 layout = SIL_PERF_EVENT;
3219 #ifdef __ARCH_SI_TRAPNO
3220 else if (layout == SIL_FAULT)
3221 layout = SIL_FAULT_TRAPNO;
3224 else if (si_code <= NSIGPOLL)
3227 if (si_code == SI_TIMER)
3229 else if (si_code == SI_SIGIO)
3231 else if (si_code < 0)
3237 static inline char __user *si_expansion(const siginfo_t __user *info)
3239 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3242 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3244 char __user *expansion = si_expansion(to);
3245 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3247 if (clear_user(expansion, SI_EXPANSION_SIZE))
3252 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3253 const siginfo_t __user *from)
3255 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3256 char __user *expansion = si_expansion(from);
3257 char buf[SI_EXPANSION_SIZE];
3260 * An unknown si_code might need more than
3261 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3262 * extra bytes are 0. This guarantees copy_siginfo_to_user
3263 * will return this data to userspace exactly.
3265 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3267 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3275 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3276 const siginfo_t __user *from)
3278 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3280 to->si_signo = signo;
3281 return post_copy_siginfo_from_user(to, from);
3284 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3286 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3288 return post_copy_siginfo_from_user(to, from);
3291 #ifdef CONFIG_COMPAT
3293 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3294 * @to: compat siginfo destination
3295 * @from: kernel siginfo source
3297 * Note: This function does not work properly for the SIGCHLD on x32, but
3298 * fortunately it doesn't have to. The only valid callers for this function are
3299 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3300 * The latter does not care because SIGCHLD will never cause a coredump.
3302 void copy_siginfo_to_external32(struct compat_siginfo *to,
3303 const struct kernel_siginfo *from)
3305 memset(to, 0, sizeof(*to));
3307 to->si_signo = from->si_signo;
3308 to->si_errno = from->si_errno;
3309 to->si_code = from->si_code;
3310 switch(siginfo_layout(from->si_signo, from->si_code)) {
3312 to->si_pid = from->si_pid;
3313 to->si_uid = from->si_uid;
3316 to->si_tid = from->si_tid;
3317 to->si_overrun = from->si_overrun;
3318 to->si_int = from->si_int;
3321 to->si_band = from->si_band;
3322 to->si_fd = from->si_fd;
3325 to->si_addr = ptr_to_compat(from->si_addr);
3327 case SIL_FAULT_TRAPNO:
3328 to->si_addr = ptr_to_compat(from->si_addr);
3329 to->si_trapno = from->si_trapno;
3331 case SIL_FAULT_MCEERR:
3332 to->si_addr = ptr_to_compat(from->si_addr);
3333 to->si_addr_lsb = from->si_addr_lsb;
3335 case SIL_FAULT_BNDERR:
3336 to->si_addr = ptr_to_compat(from->si_addr);
3337 to->si_lower = ptr_to_compat(from->si_lower);
3338 to->si_upper = ptr_to_compat(from->si_upper);
3340 case SIL_FAULT_PKUERR:
3341 to->si_addr = ptr_to_compat(from->si_addr);
3342 to->si_pkey = from->si_pkey;
3344 case SIL_PERF_EVENT:
3345 to->si_addr = ptr_to_compat(from->si_addr);
3346 to->si_perf = from->si_perf;
3349 to->si_pid = from->si_pid;
3350 to->si_uid = from->si_uid;
3351 to->si_status = from->si_status;
3352 to->si_utime = from->si_utime;
3353 to->si_stime = from->si_stime;
3356 to->si_pid = from->si_pid;
3357 to->si_uid = from->si_uid;
3358 to->si_int = from->si_int;
3361 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3362 to->si_syscall = from->si_syscall;
3363 to->si_arch = from->si_arch;
3368 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3369 const struct kernel_siginfo *from)
3371 struct compat_siginfo new;
3373 copy_siginfo_to_external32(&new, from);
3374 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3379 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3380 const struct compat_siginfo *from)
3383 to->si_signo = from->si_signo;
3384 to->si_errno = from->si_errno;
3385 to->si_code = from->si_code;
3386 switch(siginfo_layout(from->si_signo, from->si_code)) {
3388 to->si_pid = from->si_pid;
3389 to->si_uid = from->si_uid;
3392 to->si_tid = from->si_tid;
3393 to->si_overrun = from->si_overrun;
3394 to->si_int = from->si_int;
3397 to->si_band = from->si_band;
3398 to->si_fd = from->si_fd;
3401 to->si_addr = compat_ptr(from->si_addr);
3403 case SIL_FAULT_TRAPNO:
3404 to->si_addr = compat_ptr(from->si_addr);
3405 to->si_trapno = from->si_trapno;
3407 case SIL_FAULT_MCEERR:
3408 to->si_addr = compat_ptr(from->si_addr);
3409 to->si_addr_lsb = from->si_addr_lsb;
3411 case SIL_FAULT_BNDERR:
3412 to->si_addr = compat_ptr(from->si_addr);
3413 to->si_lower = compat_ptr(from->si_lower);
3414 to->si_upper = compat_ptr(from->si_upper);
3416 case SIL_FAULT_PKUERR:
3417 to->si_addr = compat_ptr(from->si_addr);
3418 to->si_pkey = from->si_pkey;
3420 case SIL_PERF_EVENT:
3421 to->si_addr = compat_ptr(from->si_addr);
3422 to->si_perf = from->si_perf;
3425 to->si_pid = from->si_pid;
3426 to->si_uid = from->si_uid;
3427 to->si_status = from->si_status;
3428 #ifdef CONFIG_X86_X32_ABI
3429 if (in_x32_syscall()) {
3430 to->si_utime = from->_sifields._sigchld_x32._utime;
3431 to->si_stime = from->_sifields._sigchld_x32._stime;
3435 to->si_utime = from->si_utime;
3436 to->si_stime = from->si_stime;
3440 to->si_pid = from->si_pid;
3441 to->si_uid = from->si_uid;
3442 to->si_int = from->si_int;
3445 to->si_call_addr = compat_ptr(from->si_call_addr);
3446 to->si_syscall = from->si_syscall;
3447 to->si_arch = from->si_arch;
3453 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3454 const struct compat_siginfo __user *ufrom)
3456 struct compat_siginfo from;
3458 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3461 from.si_signo = signo;
3462 return post_copy_siginfo_from_user32(to, &from);
3465 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3466 const struct compat_siginfo __user *ufrom)
3468 struct compat_siginfo from;
3470 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3473 return post_copy_siginfo_from_user32(to, &from);
3475 #endif /* CONFIG_COMPAT */
3478 * do_sigtimedwait - wait for queued signals specified in @which
3479 * @which: queued signals to wait for
3480 * @info: if non-null, the signal's siginfo is returned here
3481 * @ts: upper bound on process time suspension
3483 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3484 const struct timespec64 *ts)
3486 ktime_t *to = NULL, timeout = KTIME_MAX;
3487 struct task_struct *tsk = current;
3488 sigset_t mask = *which;
3492 if (!timespec64_valid(ts))
3494 timeout = timespec64_to_ktime(*ts);
3499 * Invert the set of allowed signals to get those we want to block.
3501 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3504 spin_lock_irq(&tsk->sighand->siglock);
3505 sig = dequeue_signal(tsk, &mask, info);
3506 if (!sig && timeout) {
3508 * None ready, temporarily unblock those we're interested
3509 * while we are sleeping in so that we'll be awakened when
3510 * they arrive. Unblocking is always fine, we can avoid
3511 * set_current_blocked().
3513 tsk->real_blocked = tsk->blocked;
3514 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3515 recalc_sigpending();
3516 spin_unlock_irq(&tsk->sighand->siglock);
3518 __set_current_state(TASK_INTERRUPTIBLE);
3519 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3521 spin_lock_irq(&tsk->sighand->siglock);
3522 __set_task_blocked(tsk, &tsk->real_blocked);
3523 sigemptyset(&tsk->real_blocked);
3524 sig = dequeue_signal(tsk, &mask, info);
3526 spin_unlock_irq(&tsk->sighand->siglock);
3530 return ret ? -EINTR : -EAGAIN;
3534 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3536 * @uthese: queued signals to wait for
3537 * @uinfo: if non-null, the signal's siginfo is returned here
3538 * @uts: upper bound on process time suspension
3539 * @sigsetsize: size of sigset_t type
3541 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3542 siginfo_t __user *, uinfo,
3543 const struct __kernel_timespec __user *, uts,
3547 struct timespec64 ts;
3548 kernel_siginfo_t info;
3551 /* XXX: Don't preclude handling different sized sigset_t's. */
3552 if (sigsetsize != sizeof(sigset_t))
3555 if (copy_from_user(&these, uthese, sizeof(these)))
3559 if (get_timespec64(&ts, uts))
3563 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3565 if (ret > 0 && uinfo) {
3566 if (copy_siginfo_to_user(uinfo, &info))
3573 #ifdef CONFIG_COMPAT_32BIT_TIME
3574 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3575 siginfo_t __user *, uinfo,
3576 const struct old_timespec32 __user *, uts,
3580 struct timespec64 ts;
3581 kernel_siginfo_t info;
3584 if (sigsetsize != sizeof(sigset_t))
3587 if (copy_from_user(&these, uthese, sizeof(these)))
3591 if (get_old_timespec32(&ts, uts))
3595 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3597 if (ret > 0 && uinfo) {
3598 if (copy_siginfo_to_user(uinfo, &info))
3606 #ifdef CONFIG_COMPAT
3607 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3608 struct compat_siginfo __user *, uinfo,
3609 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3612 struct timespec64 t;
3613 kernel_siginfo_t info;
3616 if (sigsetsize != sizeof(sigset_t))
3619 if (get_compat_sigset(&s, uthese))
3623 if (get_timespec64(&t, uts))
3627 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3629 if (ret > 0 && uinfo) {
3630 if (copy_siginfo_to_user32(uinfo, &info))
3637 #ifdef CONFIG_COMPAT_32BIT_TIME
3638 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3639 struct compat_siginfo __user *, uinfo,
3640 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3643 struct timespec64 t;
3644 kernel_siginfo_t info;
3647 if (sigsetsize != sizeof(sigset_t))
3650 if (get_compat_sigset(&s, uthese))
3654 if (get_old_timespec32(&t, uts))
3658 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3660 if (ret > 0 && uinfo) {
3661 if (copy_siginfo_to_user32(uinfo, &info))
3670 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3672 clear_siginfo(info);
3673 info->si_signo = sig;
3675 info->si_code = SI_USER;
3676 info->si_pid = task_tgid_vnr(current);
3677 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3681 * sys_kill - send a signal to a process
3682 * @pid: the PID of the process
3683 * @sig: signal to be sent
3685 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3687 struct kernel_siginfo info;
3689 prepare_kill_siginfo(sig, &info);
3691 return kill_something_info(sig, &info, pid);
3695 * Verify that the signaler and signalee either are in the same pid namespace
3696 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3699 static bool access_pidfd_pidns(struct pid *pid)
3701 struct pid_namespace *active = task_active_pid_ns(current);
3702 struct pid_namespace *p = ns_of_pid(pid);
3715 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
3716 siginfo_t __user *info)
3718 #ifdef CONFIG_COMPAT
3720 * Avoid hooking up compat syscalls and instead handle necessary
3721 * conversions here. Note, this is a stop-gap measure and should not be
3722 * considered a generic solution.
3724 if (in_compat_syscall())
3725 return copy_siginfo_from_user32(
3726 kinfo, (struct compat_siginfo __user *)info);
3728 return copy_siginfo_from_user(kinfo, info);
3731 static struct pid *pidfd_to_pid(const struct file *file)
3735 pid = pidfd_pid(file);
3739 return tgid_pidfd_to_pid(file);
3743 * sys_pidfd_send_signal - Signal a process through a pidfd
3744 * @pidfd: file descriptor of the process
3745 * @sig: signal to send
3746 * @info: signal info
3747 * @flags: future flags
3749 * The syscall currently only signals via PIDTYPE_PID which covers
3750 * kill(<positive-pid>, <signal>. It does not signal threads or process
3752 * In order to extend the syscall to threads and process groups the @flags
3753 * argument should be used. In essence, the @flags argument will determine
3754 * what is signaled and not the file descriptor itself. Put in other words,
3755 * grouping is a property of the flags argument not a property of the file
3758 * Return: 0 on success, negative errno on failure
3760 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3761 siginfo_t __user *, info, unsigned int, flags)
3766 kernel_siginfo_t kinfo;
3768 /* Enforce flags be set to 0 until we add an extension. */
3776 /* Is this a pidfd? */
3777 pid = pidfd_to_pid(f.file);
3784 if (!access_pidfd_pidns(pid))
3788 ret = copy_siginfo_from_user_any(&kinfo, info);
3793 if (unlikely(sig != kinfo.si_signo))
3796 /* Only allow sending arbitrary signals to yourself. */
3798 if ((task_pid(current) != pid) &&
3799 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3802 prepare_kill_siginfo(sig, &kinfo);
3805 ret = kill_pid_info(sig, &kinfo, pid);
3813 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3815 struct task_struct *p;
3819 p = find_task_by_vpid(pid);
3820 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3821 error = check_kill_permission(sig, info, p);
3823 * The null signal is a permissions and process existence
3824 * probe. No signal is actually delivered.
3826 if (!error && sig) {
3827 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3829 * If lock_task_sighand() failed we pretend the task
3830 * dies after receiving the signal. The window is tiny,
3831 * and the signal is private anyway.
3833 if (unlikely(error == -ESRCH))
3842 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3844 struct kernel_siginfo info;
3846 clear_siginfo(&info);
3847 info.si_signo = sig;
3849 info.si_code = SI_TKILL;
3850 info.si_pid = task_tgid_vnr(current);
3851 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3853 return do_send_specific(tgid, pid, sig, &info);
3857 * sys_tgkill - send signal to one specific thread
3858 * @tgid: the thread group ID of the thread
3859 * @pid: the PID of the thread
3860 * @sig: signal to be sent
3862 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3863 * exists but it's not belonging to the target process anymore. This
3864 * method solves the problem of threads exiting and PIDs getting reused.
3866 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3868 /* This is only valid for single tasks */
3869 if (pid <= 0 || tgid <= 0)
3872 return do_tkill(tgid, pid, sig);
3876 * sys_tkill - send signal to one specific task
3877 * @pid: the PID of the task
3878 * @sig: signal to be sent
3880 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3882 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3884 /* This is only valid for single tasks */
3888 return do_tkill(0, pid, sig);
3891 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3893 /* Not even root can pretend to send signals from the kernel.
3894 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3896 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3897 (task_pid_vnr(current) != pid))
3900 /* POSIX.1b doesn't mention process groups. */
3901 return kill_proc_info(sig, info, pid);
3905 * sys_rt_sigqueueinfo - send signal information to a signal
3906 * @pid: the PID of the thread
3907 * @sig: signal to be sent
3908 * @uinfo: signal info to be sent
3910 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3911 siginfo_t __user *, uinfo)
3913 kernel_siginfo_t info;
3914 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3917 return do_rt_sigqueueinfo(pid, sig, &info);
3920 #ifdef CONFIG_COMPAT
3921 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3924 struct compat_siginfo __user *, uinfo)
3926 kernel_siginfo_t info;
3927 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3930 return do_rt_sigqueueinfo(pid, sig, &info);
3934 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
3936 /* This is only valid for single tasks */
3937 if (pid <= 0 || tgid <= 0)
3940 /* Not even root can pretend to send signals from the kernel.
3941 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3943 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3944 (task_pid_vnr(current) != pid))
3947 return do_send_specific(tgid, pid, sig, info);
3950 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3951 siginfo_t __user *, uinfo)
3953 kernel_siginfo_t info;
3954 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3957 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3960 #ifdef CONFIG_COMPAT
3961 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3965 struct compat_siginfo __user *, uinfo)
3967 kernel_siginfo_t info;
3968 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3971 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3976 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3978 void kernel_sigaction(int sig, __sighandler_t action)
3980 spin_lock_irq(¤t->sighand->siglock);
3981 current->sighand->action[sig - 1].sa.sa_handler = action;
3982 if (action == SIG_IGN) {
3986 sigaddset(&mask, sig);
3988 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3989 flush_sigqueue_mask(&mask, ¤t->pending);
3990 recalc_sigpending();
3992 spin_unlock_irq(¤t->sighand->siglock);
3994 EXPORT_SYMBOL(kernel_sigaction);
3996 void __weak sigaction_compat_abi(struct k_sigaction *act,
3997 struct k_sigaction *oact)
4001 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
4003 struct task_struct *p = current, *t;
4004 struct k_sigaction *k;
4007 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
4010 k = &p->sighand->action[sig-1];
4012 spin_lock_irq(&p->sighand->siglock);
4017 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
4018 * e.g. by having an architecture use the bit in their uapi.
4020 BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
4023 * Clear unknown flag bits in order to allow userspace to detect missing
4024 * support for flag bits and to allow the kernel to use non-uapi bits
4028 act->sa.sa_flags &= UAPI_SA_FLAGS;
4030 oact->sa.sa_flags &= UAPI_SA_FLAGS;
4032 sigaction_compat_abi(act, oact);
4035 sigdelsetmask(&act->sa.sa_mask,
4036 sigmask(SIGKILL) | sigmask(SIGSTOP));
4040 * "Setting a signal action to SIG_IGN for a signal that is
4041 * pending shall cause the pending signal to be discarded,
4042 * whether or not it is blocked."
4044 * "Setting a signal action to SIG_DFL for a signal that is
4045 * pending and whose default action is to ignore the signal
4046 * (for example, SIGCHLD), shall cause the pending signal to
4047 * be discarded, whether or not it is blocked"
4049 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
4051 sigaddset(&mask, sig);
4052 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
4053 for_each_thread(p, t)
4054 flush_sigqueue_mask(&mask, &t->pending);
4058 spin_unlock_irq(&p->sighand->siglock);
4063 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4066 struct task_struct *t = current;
4069 memset(oss, 0, sizeof(stack_t));
4070 oss->ss_sp = (void __user *) t->sas_ss_sp;
4071 oss->ss_size = t->sas_ss_size;
4072 oss->ss_flags = sas_ss_flags(sp) |
4073 (current->sas_ss_flags & SS_FLAG_BITS);
4077 void __user *ss_sp = ss->ss_sp;
4078 size_t ss_size = ss->ss_size;
4079 unsigned ss_flags = ss->ss_flags;
4082 if (unlikely(on_sig_stack(sp)))
4085 ss_mode = ss_flags & ~SS_FLAG_BITS;
4086 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4090 if (ss_mode == SS_DISABLE) {
4094 if (unlikely(ss_size < min_ss_size))
4098 t->sas_ss_sp = (unsigned long) ss_sp;
4099 t->sas_ss_size = ss_size;
4100 t->sas_ss_flags = ss_flags;
4105 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4109 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4111 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4112 current_user_stack_pointer(),
4114 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4119 int restore_altstack(const stack_t __user *uss)
4122 if (copy_from_user(&new, uss, sizeof(stack_t)))
4124 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4126 /* squash all but EFAULT for now */
4130 int __save_altstack(stack_t __user *uss, unsigned long sp)
4132 struct task_struct *t = current;
4133 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4134 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4135 __put_user(t->sas_ss_size, &uss->ss_size);
4138 if (t->sas_ss_flags & SS_AUTODISARM)
4143 #ifdef CONFIG_COMPAT
4144 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4145 compat_stack_t __user *uoss_ptr)
4151 compat_stack_t uss32;
4152 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4154 uss.ss_sp = compat_ptr(uss32.ss_sp);
4155 uss.ss_flags = uss32.ss_flags;
4156 uss.ss_size = uss32.ss_size;
4158 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4159 compat_user_stack_pointer(),
4160 COMPAT_MINSIGSTKSZ);
4161 if (ret >= 0 && uoss_ptr) {
4163 memset(&old, 0, sizeof(old));
4164 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4165 old.ss_flags = uoss.ss_flags;
4166 old.ss_size = uoss.ss_size;
4167 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4173 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4174 const compat_stack_t __user *, uss_ptr,
4175 compat_stack_t __user *, uoss_ptr)
4177 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4180 int compat_restore_altstack(const compat_stack_t __user *uss)
4182 int err = do_compat_sigaltstack(uss, NULL);
4183 /* squash all but -EFAULT for now */
4184 return err == -EFAULT ? err : 0;
4187 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4190 struct task_struct *t = current;
4191 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4193 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4194 __put_user(t->sas_ss_size, &uss->ss_size);
4197 if (t->sas_ss_flags & SS_AUTODISARM)
4203 #ifdef __ARCH_WANT_SYS_SIGPENDING
4206 * sys_sigpending - examine pending signals
4207 * @uset: where mask of pending signal is returned
4209 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4213 if (sizeof(old_sigset_t) > sizeof(*uset))
4216 do_sigpending(&set);
4218 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4224 #ifdef CONFIG_COMPAT
4225 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4229 do_sigpending(&set);
4231 return put_user(set.sig[0], set32);
4237 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4239 * sys_sigprocmask - examine and change blocked signals
4240 * @how: whether to add, remove, or set signals
4241 * @nset: signals to add or remove (if non-null)
4242 * @oset: previous value of signal mask if non-null
4244 * Some platforms have their own version with special arguments;
4245 * others support only sys_rt_sigprocmask.
4248 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4249 old_sigset_t __user *, oset)
4251 old_sigset_t old_set, new_set;
4252 sigset_t new_blocked;
4254 old_set = current->blocked.sig[0];
4257 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4260 new_blocked = current->blocked;
4264 sigaddsetmask(&new_blocked, new_set);
4267 sigdelsetmask(&new_blocked, new_set);
4270 new_blocked.sig[0] = new_set;
4276 set_current_blocked(&new_blocked);
4280 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4286 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4288 #ifndef CONFIG_ODD_RT_SIGACTION
4290 * sys_rt_sigaction - alter an action taken by a process
4291 * @sig: signal to be sent
4292 * @act: new sigaction
4293 * @oact: used to save the previous sigaction
4294 * @sigsetsize: size of sigset_t type
4296 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4297 const struct sigaction __user *, act,
4298 struct sigaction __user *, oact,
4301 struct k_sigaction new_sa, old_sa;
4304 /* XXX: Don't preclude handling different sized sigset_t's. */
4305 if (sigsetsize != sizeof(sigset_t))
4308 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4311 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4315 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4320 #ifdef CONFIG_COMPAT
4321 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4322 const struct compat_sigaction __user *, act,
4323 struct compat_sigaction __user *, oact,
4324 compat_size_t, sigsetsize)
4326 struct k_sigaction new_ka, old_ka;
4327 #ifdef __ARCH_HAS_SA_RESTORER
4328 compat_uptr_t restorer;
4332 /* XXX: Don't preclude handling different sized sigset_t's. */
4333 if (sigsetsize != sizeof(compat_sigset_t))
4337 compat_uptr_t handler;
4338 ret = get_user(handler, &act->sa_handler);
4339 new_ka.sa.sa_handler = compat_ptr(handler);
4340 #ifdef __ARCH_HAS_SA_RESTORER
4341 ret |= get_user(restorer, &act->sa_restorer);
4342 new_ka.sa.sa_restorer = compat_ptr(restorer);
4344 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4345 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4350 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4352 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4354 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4355 sizeof(oact->sa_mask));
4356 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4357 #ifdef __ARCH_HAS_SA_RESTORER
4358 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4359 &oact->sa_restorer);
4365 #endif /* !CONFIG_ODD_RT_SIGACTION */
4367 #ifdef CONFIG_OLD_SIGACTION
4368 SYSCALL_DEFINE3(sigaction, int, sig,
4369 const struct old_sigaction __user *, act,
4370 struct old_sigaction __user *, oact)
4372 struct k_sigaction new_ka, old_ka;
4377 if (!access_ok(act, sizeof(*act)) ||
4378 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4379 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4380 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4381 __get_user(mask, &act->sa_mask))
4383 #ifdef __ARCH_HAS_KA_RESTORER
4384 new_ka.ka_restorer = NULL;
4386 siginitset(&new_ka.sa.sa_mask, mask);
4389 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4392 if (!access_ok(oact, sizeof(*oact)) ||
4393 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4394 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4395 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4396 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4403 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4404 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4405 const struct compat_old_sigaction __user *, act,
4406 struct compat_old_sigaction __user *, oact)
4408 struct k_sigaction new_ka, old_ka;
4410 compat_old_sigset_t mask;
4411 compat_uptr_t handler, restorer;
4414 if (!access_ok(act, sizeof(*act)) ||
4415 __get_user(handler, &act->sa_handler) ||
4416 __get_user(restorer, &act->sa_restorer) ||
4417 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4418 __get_user(mask, &act->sa_mask))
4421 #ifdef __ARCH_HAS_KA_RESTORER
4422 new_ka.ka_restorer = NULL;
4424 new_ka.sa.sa_handler = compat_ptr(handler);
4425 new_ka.sa.sa_restorer = compat_ptr(restorer);
4426 siginitset(&new_ka.sa.sa_mask, mask);
4429 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4432 if (!access_ok(oact, sizeof(*oact)) ||
4433 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4434 &oact->sa_handler) ||
4435 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4436 &oact->sa_restorer) ||
4437 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4438 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4445 #ifdef CONFIG_SGETMASK_SYSCALL
4448 * For backwards compatibility. Functionality superseded by sigprocmask.
4450 SYSCALL_DEFINE0(sgetmask)
4453 return current->blocked.sig[0];
4456 SYSCALL_DEFINE1(ssetmask, int, newmask)
4458 int old = current->blocked.sig[0];
4461 siginitset(&newset, newmask);
4462 set_current_blocked(&newset);
4466 #endif /* CONFIG_SGETMASK_SYSCALL */
4468 #ifdef __ARCH_WANT_SYS_SIGNAL
4470 * For backwards compatibility. Functionality superseded by sigaction.
4472 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4474 struct k_sigaction new_sa, old_sa;
4477 new_sa.sa.sa_handler = handler;
4478 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4479 sigemptyset(&new_sa.sa.sa_mask);
4481 ret = do_sigaction(sig, &new_sa, &old_sa);
4483 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4485 #endif /* __ARCH_WANT_SYS_SIGNAL */
4487 #ifdef __ARCH_WANT_SYS_PAUSE
4489 SYSCALL_DEFINE0(pause)
4491 while (!signal_pending(current)) {
4492 __set_current_state(TASK_INTERRUPTIBLE);
4495 return -ERESTARTNOHAND;
4500 static int sigsuspend(sigset_t *set)
4502 current->saved_sigmask = current->blocked;
4503 set_current_blocked(set);
4505 while (!signal_pending(current)) {
4506 __set_current_state(TASK_INTERRUPTIBLE);
4509 set_restore_sigmask();
4510 return -ERESTARTNOHAND;
4514 * sys_rt_sigsuspend - replace the signal mask for a value with the
4515 * @unewset value until a signal is received
4516 * @unewset: new signal mask value
4517 * @sigsetsize: size of sigset_t type
4519 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4523 /* XXX: Don't preclude handling different sized sigset_t's. */
4524 if (sigsetsize != sizeof(sigset_t))
4527 if (copy_from_user(&newset, unewset, sizeof(newset)))
4529 return sigsuspend(&newset);
4532 #ifdef CONFIG_COMPAT
4533 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4537 /* XXX: Don't preclude handling different sized sigset_t's. */
4538 if (sigsetsize != sizeof(sigset_t))
4541 if (get_compat_sigset(&newset, unewset))
4543 return sigsuspend(&newset);
4547 #ifdef CONFIG_OLD_SIGSUSPEND
4548 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4551 siginitset(&blocked, mask);
4552 return sigsuspend(&blocked);
4555 #ifdef CONFIG_OLD_SIGSUSPEND3
4556 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4559 siginitset(&blocked, mask);
4560 return sigsuspend(&blocked);
4564 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4569 static inline void siginfo_buildtime_checks(void)
4571 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4573 /* Verify the offsets in the two siginfos match */
4574 #define CHECK_OFFSET(field) \
4575 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4578 CHECK_OFFSET(si_pid);
4579 CHECK_OFFSET(si_uid);
4582 CHECK_OFFSET(si_tid);
4583 CHECK_OFFSET(si_overrun);
4584 CHECK_OFFSET(si_value);
4587 CHECK_OFFSET(si_pid);
4588 CHECK_OFFSET(si_uid);
4589 CHECK_OFFSET(si_value);
4592 CHECK_OFFSET(si_pid);
4593 CHECK_OFFSET(si_uid);
4594 CHECK_OFFSET(si_status);
4595 CHECK_OFFSET(si_utime);
4596 CHECK_OFFSET(si_stime);
4599 CHECK_OFFSET(si_addr);
4600 CHECK_OFFSET(si_trapno);
4601 CHECK_OFFSET(si_addr_lsb);
4602 CHECK_OFFSET(si_lower);
4603 CHECK_OFFSET(si_upper);
4604 CHECK_OFFSET(si_pkey);
4605 CHECK_OFFSET(si_perf);
4608 CHECK_OFFSET(si_band);
4609 CHECK_OFFSET(si_fd);
4612 CHECK_OFFSET(si_call_addr);
4613 CHECK_OFFSET(si_syscall);
4614 CHECK_OFFSET(si_arch);
4618 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4619 offsetof(struct siginfo, si_addr));
4620 if (sizeof(int) == sizeof(void __user *)) {
4621 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4622 sizeof(void __user *));
4624 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4625 sizeof_field(struct siginfo, si_uid)) !=
4626 sizeof(void __user *));
4627 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4628 offsetof(struct siginfo, si_uid));
4630 #ifdef CONFIG_COMPAT
4631 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4632 offsetof(struct compat_siginfo, si_addr));
4633 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4634 sizeof(compat_uptr_t));
4635 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4636 sizeof_field(struct siginfo, si_pid));
4640 void __init signals_init(void)
4642 siginfo_buildtime_checks();
4644 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
4647 #ifdef CONFIG_KGDB_KDB
4648 #include <linux/kdb.h>
4650 * kdb_send_sig - Allows kdb to send signals without exposing
4651 * signal internals. This function checks if the required locks are
4652 * available before calling the main signal code, to avoid kdb
4655 void kdb_send_sig(struct task_struct *t, int sig)
4657 static struct task_struct *kdb_prev_t;
4659 if (!spin_trylock(&t->sighand->siglock)) {
4660 kdb_printf("Can't do kill command now.\n"
4661 "The sigmask lock is held somewhere else in "
4662 "kernel, try again later\n");
4665 new_t = kdb_prev_t != t;
4667 if (t->state != TASK_RUNNING && new_t) {
4668 spin_unlock(&t->sighand->siglock);
4669 kdb_printf("Process is not RUNNING, sending a signal from "
4670 "kdb risks deadlock\n"
4671 "on the run queue locks. "
4672 "The signal has _not_ been sent.\n"
4673 "Reissue the kill command if you want to risk "
4677 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4678 spin_unlock(&t->sighand->siglock);
4680 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4683 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4685 #endif /* CONFIG_KGDB_KDB */