1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
9 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
10 * Changes to use preallocated sigqueue structures
11 * to allow signals to be sent reliably.
14 #include <linux/slab.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/debug.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/sched/cputime.h>
23 #include <linux/file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/tty.h>
27 #include <linux/binfmts.h>
28 #include <linux/coredump.h>
29 #include <linux/security.h>
30 #include <linux/syscalls.h>
31 #include <linux/ptrace.h>
32 #include <linux/signal.h>
33 #include <linux/signalfd.h>
34 #include <linux/ratelimit.h>
35 #include <linux/tracehook.h>
36 #include <linux/capability.h>
37 #include <linux/freezer.h>
38 #include <linux/pid_namespace.h>
39 #include <linux/nsproxy.h>
40 #include <linux/user_namespace.h>
41 #include <linux/uprobes.h>
42 #include <linux/compat.h>
43 #include <linux/cn_proc.h>
44 #include <linux/compiler.h>
45 #include <linux/posix-timers.h>
46 #include <linux/livepatch.h>
47 #include <linux/cgroup.h>
48 #include <linux/audit.h>
50 #define CREATE_TRACE_POINTS
51 #include <trace/events/signal.h>
53 #include <asm/param.h>
54 #include <linux/uaccess.h>
55 #include <asm/unistd.h>
56 #include <asm/siginfo.h>
57 #include <asm/cacheflush.h>
60 * SLAB caches for signal bits.
63 static struct kmem_cache *sigqueue_cachep;
65 int print_fatal_signals __read_mostly;
67 static void __user *sig_handler(struct task_struct *t, int sig)
69 return t->sighand->action[sig - 1].sa.sa_handler;
72 static inline bool sig_handler_ignored(void __user *handler, int sig)
74 /* Is it explicitly or implicitly ignored? */
75 return handler == SIG_IGN ||
76 (handler == SIG_DFL && sig_kernel_ignore(sig));
79 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
83 handler = sig_handler(t, sig);
85 /* SIGKILL and SIGSTOP may not be sent to the global init */
86 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
89 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
90 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
93 /* Only allow kernel generated signals to this kthread */
94 if (unlikely((t->flags & (PF_KTHREAD | PF_IO_WORKER)) &&
95 (handler == SIG_KTHREAD_KERNEL) && !force))
98 return sig_handler_ignored(handler, sig);
101 static bool sig_ignored(struct task_struct *t, int sig, bool force)
104 * Blocked signals are never ignored, since the
105 * signal handler may change by the time it is
108 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
112 * Tracers may want to know about even ignored signal unless it
113 * is SIGKILL which can't be reported anyway but can be ignored
114 * by SIGNAL_UNKILLABLE task.
116 if (t->ptrace && sig != SIGKILL)
119 return sig_task_ignored(t, sig, force);
123 * Re-calculate pending state from the set of locally pending
124 * signals, globally pending signals, and blocked signals.
126 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
131 switch (_NSIG_WORDS) {
133 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
134 ready |= signal->sig[i] &~ blocked->sig[i];
137 case 4: ready = signal->sig[3] &~ blocked->sig[3];
138 ready |= signal->sig[2] &~ blocked->sig[2];
139 ready |= signal->sig[1] &~ blocked->sig[1];
140 ready |= signal->sig[0] &~ blocked->sig[0];
143 case 2: ready = signal->sig[1] &~ blocked->sig[1];
144 ready |= signal->sig[0] &~ blocked->sig[0];
147 case 1: ready = signal->sig[0] &~ blocked->sig[0];
152 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
154 static bool recalc_sigpending_tsk(struct task_struct *t)
156 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
157 PENDING(&t->pending, &t->blocked) ||
158 PENDING(&t->signal->shared_pending, &t->blocked) ||
159 cgroup_task_frozen(t)) {
160 set_tsk_thread_flag(t, TIF_SIGPENDING);
165 * We must never clear the flag in another thread, or in current
166 * when it's possible the current syscall is returning -ERESTART*.
167 * So we don't clear it here, and only callers who know they should do.
173 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
174 * This is superfluous when called on current, the wakeup is a harmless no-op.
176 void recalc_sigpending_and_wake(struct task_struct *t)
178 if (recalc_sigpending_tsk(t))
179 signal_wake_up(t, 0);
182 void recalc_sigpending(void)
184 if (!recalc_sigpending_tsk(current) && !freezing(current) &&
185 !klp_patch_pending(current))
186 clear_thread_flag(TIF_SIGPENDING);
189 EXPORT_SYMBOL(recalc_sigpending);
191 void calculate_sigpending(void)
193 /* Have any signals or users of TIF_SIGPENDING been delayed
196 spin_lock_irq(¤t->sighand->siglock);
197 set_tsk_thread_flag(current, TIF_SIGPENDING);
199 spin_unlock_irq(¤t->sighand->siglock);
202 /* Given the mask, find the first available signal that should be serviced. */
204 #define SYNCHRONOUS_MASK \
205 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
206 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
208 int next_signal(struct sigpending *pending, sigset_t *mask)
210 unsigned long i, *s, *m, x;
213 s = pending->signal.sig;
217 * Handle the first word specially: it contains the
218 * synchronous signals that need to be dequeued first.
222 if (x & SYNCHRONOUS_MASK)
223 x &= SYNCHRONOUS_MASK;
228 switch (_NSIG_WORDS) {
230 for (i = 1; i < _NSIG_WORDS; ++i) {
234 sig = ffz(~x) + i*_NSIG_BPW + 1;
243 sig = ffz(~x) + _NSIG_BPW + 1;
254 static inline void print_dropped_signal(int sig)
256 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
258 if (!print_fatal_signals)
261 if (!__ratelimit(&ratelimit_state))
264 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
265 current->comm, current->pid, sig);
269 * task_set_jobctl_pending - set jobctl pending bits
271 * @mask: pending bits to set
273 * Clear @mask from @task->jobctl. @mask must be subset of
274 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
275 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
276 * cleared. If @task is already being killed or exiting, this function
280 * Must be called with @task->sighand->siglock held.
283 * %true if @mask is set, %false if made noop because @task was dying.
285 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
287 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
288 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
289 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
291 if (unlikely(fatal_signal_pending(task) ||
292 (task->flags & (PF_EXITING | PF_IO_WORKER))))
295 if (mask & JOBCTL_STOP_SIGMASK)
296 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
298 task->jobctl |= mask;
303 * task_clear_jobctl_trapping - clear jobctl trapping bit
306 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
307 * Clear it and wake up the ptracer. Note that we don't need any further
308 * locking. @task->siglock guarantees that @task->parent points to the
312 * Must be called with @task->sighand->siglock held.
314 void task_clear_jobctl_trapping(struct task_struct *task)
316 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
317 task->jobctl &= ~JOBCTL_TRAPPING;
318 smp_mb(); /* advised by wake_up_bit() */
319 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
324 * task_clear_jobctl_pending - clear jobctl pending bits
326 * @mask: pending bits to clear
328 * Clear @mask from @task->jobctl. @mask must be subset of
329 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
330 * STOP bits are cleared together.
332 * If clearing of @mask leaves no stop or trap pending, this function calls
333 * task_clear_jobctl_trapping().
336 * Must be called with @task->sighand->siglock held.
338 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
340 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
342 if (mask & JOBCTL_STOP_PENDING)
343 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
345 task->jobctl &= ~mask;
347 if (!(task->jobctl & JOBCTL_PENDING_MASK))
348 task_clear_jobctl_trapping(task);
352 * task_participate_group_stop - participate in a group stop
353 * @task: task participating in a group stop
355 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
356 * Group stop states are cleared and the group stop count is consumed if
357 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
358 * stop, the appropriate `SIGNAL_*` flags are set.
361 * Must be called with @task->sighand->siglock held.
364 * %true if group stop completion should be notified to the parent, %false
367 static bool task_participate_group_stop(struct task_struct *task)
369 struct signal_struct *sig = task->signal;
370 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
372 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
374 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
379 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
380 sig->group_stop_count--;
383 * Tell the caller to notify completion iff we are entering into a
384 * fresh group stop. Read comment in do_signal_stop() for details.
386 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
387 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
393 void task_join_group_stop(struct task_struct *task)
395 unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
396 struct signal_struct *sig = current->signal;
398 if (sig->group_stop_count) {
399 sig->group_stop_count++;
400 mask |= JOBCTL_STOP_CONSUME;
401 } else if (!(sig->flags & SIGNAL_STOP_STOPPED))
404 /* Have the new thread join an on-going signal group stop */
405 task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
409 * allocate a new signal queue record
410 * - this may be called without locks if and only if t == current, otherwise an
411 * appropriate lock must be held to stop the target task from exiting
413 static struct sigqueue *
414 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
416 struct sigqueue *q = NULL;
417 struct user_struct *user;
421 * Protect access to @t credentials. This can go away when all
422 * callers hold rcu read lock.
424 * NOTE! A pending signal will hold on to the user refcount,
425 * and we get/put the refcount only when the sigpending count
426 * changes from/to zero.
429 user = __task_cred(t)->user;
430 sigpending = atomic_inc_return(&user->sigpending);
435 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
436 q = kmem_cache_alloc(sigqueue_cachep, flags);
438 print_dropped_signal(sig);
441 if (unlikely(q == NULL)) {
442 if (atomic_dec_and_test(&user->sigpending))
445 INIT_LIST_HEAD(&q->list);
453 static void __sigqueue_free(struct sigqueue *q)
455 if (q->flags & SIGQUEUE_PREALLOC)
457 if (atomic_dec_and_test(&q->user->sigpending))
459 kmem_cache_free(sigqueue_cachep, q);
462 void flush_sigqueue(struct sigpending *queue)
466 sigemptyset(&queue->signal);
467 while (!list_empty(&queue->list)) {
468 q = list_entry(queue->list.next, struct sigqueue , list);
469 list_del_init(&q->list);
475 * Flush all pending signals for this kthread.
477 void flush_signals(struct task_struct *t)
481 spin_lock_irqsave(&t->sighand->siglock, flags);
482 clear_tsk_thread_flag(t, TIF_SIGPENDING);
483 flush_sigqueue(&t->pending);
484 flush_sigqueue(&t->signal->shared_pending);
485 spin_unlock_irqrestore(&t->sighand->siglock, flags);
487 EXPORT_SYMBOL(flush_signals);
489 #ifdef CONFIG_POSIX_TIMERS
490 static void __flush_itimer_signals(struct sigpending *pending)
492 sigset_t signal, retain;
493 struct sigqueue *q, *n;
495 signal = pending->signal;
496 sigemptyset(&retain);
498 list_for_each_entry_safe(q, n, &pending->list, list) {
499 int sig = q->info.si_signo;
501 if (likely(q->info.si_code != SI_TIMER)) {
502 sigaddset(&retain, sig);
504 sigdelset(&signal, sig);
505 list_del_init(&q->list);
510 sigorsets(&pending->signal, &signal, &retain);
513 void flush_itimer_signals(void)
515 struct task_struct *tsk = current;
518 spin_lock_irqsave(&tsk->sighand->siglock, flags);
519 __flush_itimer_signals(&tsk->pending);
520 __flush_itimer_signals(&tsk->signal->shared_pending);
521 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
525 void ignore_signals(struct task_struct *t)
529 for (i = 0; i < _NSIG; ++i)
530 t->sighand->action[i].sa.sa_handler = SIG_IGN;
536 * Flush all handlers for a task.
540 flush_signal_handlers(struct task_struct *t, int force_default)
543 struct k_sigaction *ka = &t->sighand->action[0];
544 for (i = _NSIG ; i != 0 ; i--) {
545 if (force_default || ka->sa.sa_handler != SIG_IGN)
546 ka->sa.sa_handler = SIG_DFL;
548 #ifdef __ARCH_HAS_SA_RESTORER
549 ka->sa.sa_restorer = NULL;
551 sigemptyset(&ka->sa.sa_mask);
556 bool unhandled_signal(struct task_struct *tsk, int sig)
558 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
559 if (is_global_init(tsk))
562 if (handler != SIG_IGN && handler != SIG_DFL)
565 /* if ptraced, let the tracer determine */
569 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
572 struct sigqueue *q, *first = NULL;
575 * Collect the siginfo appropriate to this signal. Check if
576 * there is another siginfo for the same signal.
578 list_for_each_entry(q, &list->list, list) {
579 if (q->info.si_signo == sig) {
586 sigdelset(&list->signal, sig);
590 list_del_init(&first->list);
591 copy_siginfo(info, &first->info);
594 (first->flags & SIGQUEUE_PREALLOC) &&
595 (info->si_code == SI_TIMER) &&
596 (info->si_sys_private);
598 __sigqueue_free(first);
601 * Ok, it wasn't in the queue. This must be
602 * a fast-pathed signal or we must have been
603 * out of queue space. So zero out the info.
606 info->si_signo = sig;
608 info->si_code = SI_USER;
614 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
615 kernel_siginfo_t *info, bool *resched_timer)
617 int sig = next_signal(pending, mask);
620 collect_signal(sig, pending, info, resched_timer);
625 * Dequeue a signal and return the element to the caller, which is
626 * expected to free it.
628 * All callers have to hold the siglock.
630 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
632 bool resched_timer = false;
635 /* We only dequeue private signals from ourselves, we don't let
636 * signalfd steal them
638 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
640 signr = __dequeue_signal(&tsk->signal->shared_pending,
641 mask, info, &resched_timer);
642 #ifdef CONFIG_POSIX_TIMERS
646 * itimers are process shared and we restart periodic
647 * itimers in the signal delivery path to prevent DoS
648 * attacks in the high resolution timer case. This is
649 * compliant with the old way of self-restarting
650 * itimers, as the SIGALRM is a legacy signal and only
651 * queued once. Changing the restart behaviour to
652 * restart the timer in the signal dequeue path is
653 * reducing the timer noise on heavy loaded !highres
656 if (unlikely(signr == SIGALRM)) {
657 struct hrtimer *tmr = &tsk->signal->real_timer;
659 if (!hrtimer_is_queued(tmr) &&
660 tsk->signal->it_real_incr != 0) {
661 hrtimer_forward(tmr, tmr->base->get_time(),
662 tsk->signal->it_real_incr);
663 hrtimer_restart(tmr);
673 if (unlikely(sig_kernel_stop(signr))) {
675 * Set a marker that we have dequeued a stop signal. Our
676 * caller might release the siglock and then the pending
677 * stop signal it is about to process is no longer in the
678 * pending bitmasks, but must still be cleared by a SIGCONT
679 * (and overruled by a SIGKILL). So those cases clear this
680 * shared flag after we've set it. Note that this flag may
681 * remain set after the signal we return is ignored or
682 * handled. That doesn't matter because its only purpose
683 * is to alert stop-signal processing code when another
684 * processor has come along and cleared the flag.
686 current->jobctl |= JOBCTL_STOP_DEQUEUED;
688 #ifdef CONFIG_POSIX_TIMERS
691 * Release the siglock to ensure proper locking order
692 * of timer locks outside of siglocks. Note, we leave
693 * irqs disabled here, since the posix-timers code is
694 * about to disable them again anyway.
696 spin_unlock(&tsk->sighand->siglock);
697 posixtimer_rearm(info);
698 spin_lock(&tsk->sighand->siglock);
700 /* Don't expose the si_sys_private value to userspace */
701 info->si_sys_private = 0;
706 EXPORT_SYMBOL_GPL(dequeue_signal);
708 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
710 struct task_struct *tsk = current;
711 struct sigpending *pending = &tsk->pending;
712 struct sigqueue *q, *sync = NULL;
715 * Might a synchronous signal be in the queue?
717 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
721 * Return the first synchronous signal in the queue.
723 list_for_each_entry(q, &pending->list, list) {
724 /* Synchronous signals have a positive si_code */
725 if ((q->info.si_code > SI_USER) &&
726 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
734 * Check if there is another siginfo for the same signal.
736 list_for_each_entry_continue(q, &pending->list, list) {
737 if (q->info.si_signo == sync->info.si_signo)
741 sigdelset(&pending->signal, sync->info.si_signo);
744 list_del_init(&sync->list);
745 copy_siginfo(info, &sync->info);
746 __sigqueue_free(sync);
747 return info->si_signo;
751 * Tell a process that it has a new active signal..
753 * NOTE! we rely on the previous spin_lock to
754 * lock interrupts for us! We can only be called with
755 * "siglock" held, and the local interrupt must
756 * have been disabled when that got acquired!
758 * No need to set need_resched since signal event passing
759 * goes through ->blocked
761 void signal_wake_up_state(struct task_struct *t, unsigned int state)
763 set_tsk_thread_flag(t, TIF_SIGPENDING);
765 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
766 * case. We don't check t->state here because there is a race with it
767 * executing another processor and just now entering stopped state.
768 * By using wake_up_state, we ensure the process will wake up and
769 * handle its death signal.
771 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
776 * Remove signals in mask from the pending set and queue.
777 * Returns 1 if any signals were found.
779 * All callers must be holding the siglock.
781 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
783 struct sigqueue *q, *n;
786 sigandsets(&m, mask, &s->signal);
787 if (sigisemptyset(&m))
790 sigandnsets(&s->signal, &s->signal, mask);
791 list_for_each_entry_safe(q, n, &s->list, list) {
792 if (sigismember(mask, q->info.si_signo)) {
793 list_del_init(&q->list);
799 static inline int is_si_special(const struct kernel_siginfo *info)
801 return info <= SEND_SIG_PRIV;
804 static inline bool si_fromuser(const struct kernel_siginfo *info)
806 return info == SEND_SIG_NOINFO ||
807 (!is_si_special(info) && SI_FROMUSER(info));
811 * called with RCU read lock from check_kill_permission()
813 static bool kill_ok_by_cred(struct task_struct *t)
815 const struct cred *cred = current_cred();
816 const struct cred *tcred = __task_cred(t);
818 return uid_eq(cred->euid, tcred->suid) ||
819 uid_eq(cred->euid, tcred->uid) ||
820 uid_eq(cred->uid, tcred->suid) ||
821 uid_eq(cred->uid, tcred->uid) ||
822 ns_capable(tcred->user_ns, CAP_KILL);
826 * Bad permissions for sending the signal
827 * - the caller must hold the RCU read lock
829 static int check_kill_permission(int sig, struct kernel_siginfo *info,
830 struct task_struct *t)
835 if (!valid_signal(sig))
837 /* PF_IO_WORKER threads don't take any signals */
838 if (t->flags & PF_IO_WORKER)
841 if (!si_fromuser(info))
844 error = audit_signal_info(sig, t); /* Let audit system see the signal */
848 if (!same_thread_group(current, t) &&
849 !kill_ok_by_cred(t)) {
852 sid = task_session(t);
854 * We don't return the error if sid == NULL. The
855 * task was unhashed, the caller must notice this.
857 if (!sid || sid == task_session(current))
865 return security_task_kill(t, info, sig, NULL);
869 * ptrace_trap_notify - schedule trap to notify ptracer
870 * @t: tracee wanting to notify tracer
872 * This function schedules sticky ptrace trap which is cleared on the next
873 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
876 * If @t is running, STOP trap will be taken. If trapped for STOP and
877 * ptracer is listening for events, tracee is woken up so that it can
878 * re-trap for the new event. If trapped otherwise, STOP trap will be
879 * eventually taken without returning to userland after the existing traps
880 * are finished by PTRACE_CONT.
883 * Must be called with @task->sighand->siglock held.
885 static void ptrace_trap_notify(struct task_struct *t)
887 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
888 assert_spin_locked(&t->sighand->siglock);
890 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
891 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
895 * Handle magic process-wide effects of stop/continue signals. Unlike
896 * the signal actions, these happen immediately at signal-generation
897 * time regardless of blocking, ignoring, or handling. This does the
898 * actual continuing for SIGCONT, but not the actual stopping for stop
899 * signals. The process stop is done as a signal action for SIG_DFL.
901 * Returns true if the signal should be actually delivered, otherwise
902 * it should be dropped.
904 static bool prepare_signal(int sig, struct task_struct *p, bool force)
906 struct signal_struct *signal = p->signal;
907 struct task_struct *t;
910 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
911 if (!(signal->flags & SIGNAL_GROUP_EXIT))
912 return sig == SIGKILL;
914 * The process is in the middle of dying, nothing to do.
916 } else if (sig_kernel_stop(sig)) {
918 * This is a stop signal. Remove SIGCONT from all queues.
920 siginitset(&flush, sigmask(SIGCONT));
921 flush_sigqueue_mask(&flush, &signal->shared_pending);
922 for_each_thread(p, t)
923 flush_sigqueue_mask(&flush, &t->pending);
924 } else if (sig == SIGCONT) {
927 * Remove all stop signals from all queues, wake all threads.
929 siginitset(&flush, SIG_KERNEL_STOP_MASK);
930 flush_sigqueue_mask(&flush, &signal->shared_pending);
931 for_each_thread(p, t) {
932 flush_sigqueue_mask(&flush, &t->pending);
933 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
934 if (likely(!(t->ptrace & PT_SEIZED)))
935 wake_up_state(t, __TASK_STOPPED);
937 ptrace_trap_notify(t);
941 * Notify the parent with CLD_CONTINUED if we were stopped.
943 * If we were in the middle of a group stop, we pretend it
944 * was already finished, and then continued. Since SIGCHLD
945 * doesn't queue we report only CLD_STOPPED, as if the next
946 * CLD_CONTINUED was dropped.
949 if (signal->flags & SIGNAL_STOP_STOPPED)
950 why |= SIGNAL_CLD_CONTINUED;
951 else if (signal->group_stop_count)
952 why |= SIGNAL_CLD_STOPPED;
956 * The first thread which returns from do_signal_stop()
957 * will take ->siglock, notice SIGNAL_CLD_MASK, and
958 * notify its parent. See get_signal().
960 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
961 signal->group_stop_count = 0;
962 signal->group_exit_code = 0;
966 return !sig_ignored(p, sig, force);
970 * Test if P wants to take SIG. After we've checked all threads with this,
971 * it's equivalent to finding no threads not blocking SIG. Any threads not
972 * blocking SIG were ruled out because they are not running and already
973 * have pending signals. Such threads will dequeue from the shared queue
974 * as soon as they're available, so putting the signal on the shared queue
975 * will be equivalent to sending it to one such thread.
977 static inline bool wants_signal(int sig, struct task_struct *p)
979 if (sigismember(&p->blocked, sig))
982 if (p->flags & PF_EXITING)
988 if (task_is_stopped_or_traced(p))
991 return task_curr(p) || !task_sigpending(p);
994 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
996 struct signal_struct *signal = p->signal;
997 struct task_struct *t;
1000 * Now find a thread we can wake up to take the signal off the queue.
1002 * If the main thread wants the signal, it gets first crack.
1003 * Probably the least surprising to the average bear.
1005 if (wants_signal(sig, p))
1007 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1009 * There is just one thread and it does not need to be woken.
1010 * It will dequeue unblocked signals before it runs again.
1015 * Otherwise try to find a suitable thread.
1017 t = signal->curr_target;
1018 while (!wants_signal(sig, t)) {
1020 if (t == signal->curr_target)
1022 * No thread needs to be woken.
1023 * Any eligible threads will see
1024 * the signal in the queue soon.
1028 signal->curr_target = t;
1032 * Found a killable thread. If the signal will be fatal,
1033 * then start taking the whole group down immediately.
1035 if (sig_fatal(p, sig) &&
1036 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1037 !sigismember(&t->real_blocked, sig) &&
1038 (sig == SIGKILL || !p->ptrace)) {
1040 * This signal will be fatal to the whole group.
1042 if (!sig_kernel_coredump(sig)) {
1044 * Start a group exit and wake everybody up.
1045 * This way we don't have other threads
1046 * running and doing things after a slower
1047 * thread has the fatal signal pending.
1049 signal->flags = SIGNAL_GROUP_EXIT;
1050 signal->group_exit_code = sig;
1051 signal->group_stop_count = 0;
1054 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1055 sigaddset(&t->pending.signal, SIGKILL);
1056 signal_wake_up(t, 1);
1057 } while_each_thread(p, t);
1063 * The signal is already in the shared-pending queue.
1064 * Tell the chosen thread to wake up and dequeue it.
1066 signal_wake_up(t, sig == SIGKILL);
1070 static inline bool legacy_queue(struct sigpending *signals, int sig)
1072 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1075 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1076 enum pid_type type, bool force)
1078 struct sigpending *pending;
1080 int override_rlimit;
1081 int ret = 0, result;
1083 assert_spin_locked(&t->sighand->siglock);
1085 result = TRACE_SIGNAL_IGNORED;
1086 if (!prepare_signal(sig, t, force))
1089 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1091 * Short-circuit ignored signals and support queuing
1092 * exactly one non-rt signal, so that we can get more
1093 * detailed information about the cause of the signal.
1095 result = TRACE_SIGNAL_ALREADY_PENDING;
1096 if (legacy_queue(pending, sig))
1099 result = TRACE_SIGNAL_DELIVERED;
1101 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1103 if ((sig == SIGKILL) || (t->flags & (PF_KTHREAD | PF_IO_WORKER)))
1107 * Real-time signals must be queued if sent by sigqueue, or
1108 * some other real-time mechanism. It is implementation
1109 * defined whether kill() does so. We attempt to do so, on
1110 * the principle of least surprise, but since kill is not
1111 * allowed to fail with EAGAIN when low on memory we just
1112 * make sure at least one signal gets delivered and don't
1113 * pass on the info struct.
1116 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1118 override_rlimit = 0;
1120 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
1122 list_add_tail(&q->list, &pending->list);
1123 switch ((unsigned long) info) {
1124 case (unsigned long) SEND_SIG_NOINFO:
1125 clear_siginfo(&q->info);
1126 q->info.si_signo = sig;
1127 q->info.si_errno = 0;
1128 q->info.si_code = SI_USER;
1129 q->info.si_pid = task_tgid_nr_ns(current,
1130 task_active_pid_ns(t));
1133 from_kuid_munged(task_cred_xxx(t, user_ns),
1137 case (unsigned long) SEND_SIG_PRIV:
1138 clear_siginfo(&q->info);
1139 q->info.si_signo = sig;
1140 q->info.si_errno = 0;
1141 q->info.si_code = SI_KERNEL;
1146 copy_siginfo(&q->info, info);
1149 } else if (!is_si_special(info) &&
1150 sig >= SIGRTMIN && info->si_code != SI_USER) {
1152 * Queue overflow, abort. We may abort if the
1153 * signal was rt and sent by user using something
1154 * other than kill().
1156 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1161 * This is a silent loss of information. We still
1162 * send the signal, but the *info bits are lost.
1164 result = TRACE_SIGNAL_LOSE_INFO;
1168 signalfd_notify(t, sig);
1169 sigaddset(&pending->signal, sig);
1171 /* Let multiprocess signals appear after on-going forks */
1172 if (type > PIDTYPE_TGID) {
1173 struct multiprocess_signals *delayed;
1174 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1175 sigset_t *signal = &delayed->signal;
1176 /* Can't queue both a stop and a continue signal */
1178 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1179 else if (sig_kernel_stop(sig))
1180 sigdelset(signal, SIGCONT);
1181 sigaddset(signal, sig);
1185 complete_signal(sig, t, type);
1187 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1191 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1194 switch (siginfo_layout(info->si_signo, info->si_code)) {
1203 case SIL_FAULT_MCEERR:
1204 case SIL_FAULT_BNDERR:
1205 case SIL_FAULT_PKUERR:
1213 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1216 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1219 if (info == SEND_SIG_NOINFO) {
1220 /* Force if sent from an ancestor pid namespace */
1221 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1222 } else if (info == SEND_SIG_PRIV) {
1223 /* Don't ignore kernel generated signals */
1225 } else if (has_si_pid_and_uid(info)) {
1226 /* SIGKILL and SIGSTOP is special or has ids */
1227 struct user_namespace *t_user_ns;
1230 t_user_ns = task_cred_xxx(t, user_ns);
1231 if (current_user_ns() != t_user_ns) {
1232 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1233 info->si_uid = from_kuid_munged(t_user_ns, uid);
1237 /* A kernel generated signal? */
1238 force = (info->si_code == SI_KERNEL);
1240 /* From an ancestor pid namespace? */
1241 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1246 return __send_signal(sig, info, t, type, force);
1249 static void print_fatal_signal(int signr)
1251 struct pt_regs *regs = signal_pt_regs();
1252 pr_info("potentially unexpected fatal signal %d.\n", signr);
1254 #if defined(__i386__) && !defined(__arch_um__)
1255 pr_info("code at %08lx: ", regs->ip);
1258 for (i = 0; i < 16; i++) {
1261 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1263 pr_cont("%02x ", insn);
1273 static int __init setup_print_fatal_signals(char *str)
1275 get_option (&str, &print_fatal_signals);
1280 __setup("print-fatal-signals=", setup_print_fatal_signals);
1283 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1285 return send_signal(sig, info, p, PIDTYPE_TGID);
1288 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1291 unsigned long flags;
1294 if (lock_task_sighand(p, &flags)) {
1295 ret = send_signal(sig, info, p, type);
1296 unlock_task_sighand(p, &flags);
1303 * Force a signal that the process can't ignore: if necessary
1304 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1306 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1307 * since we do not want to have a signal handler that was blocked
1308 * be invoked when user space had explicitly blocked it.
1310 * We don't want to have recursive SIGSEGV's etc, for example,
1311 * that is why we also clear SIGNAL_UNKILLABLE.
1314 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t)
1316 unsigned long int flags;
1317 int ret, blocked, ignored;
1318 struct k_sigaction *action;
1319 int sig = info->si_signo;
1321 spin_lock_irqsave(&t->sighand->siglock, flags);
1322 action = &t->sighand->action[sig-1];
1323 ignored = action->sa.sa_handler == SIG_IGN;
1324 blocked = sigismember(&t->blocked, sig);
1325 if (blocked || ignored) {
1326 action->sa.sa_handler = SIG_DFL;
1328 sigdelset(&t->blocked, sig);
1329 recalc_sigpending_and_wake(t);
1333 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1334 * debugging to leave init killable.
1336 if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
1337 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1338 ret = send_signal(sig, info, t, PIDTYPE_PID);
1339 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1344 int force_sig_info(struct kernel_siginfo *info)
1346 return force_sig_info_to_task(info, current);
1350 * Nuke all other threads in the group.
1352 int zap_other_threads(struct task_struct *p)
1354 struct task_struct *t = p;
1357 p->signal->group_stop_count = 0;
1359 while_each_thread(p, t) {
1360 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1363 /* Don't bother with already dead threads */
1366 sigaddset(&t->pending.signal, SIGKILL);
1367 signal_wake_up(t, 1);
1373 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1374 unsigned long *flags)
1376 struct sighand_struct *sighand;
1380 sighand = rcu_dereference(tsk->sighand);
1381 if (unlikely(sighand == NULL))
1385 * This sighand can be already freed and even reused, but
1386 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1387 * initializes ->siglock: this slab can't go away, it has
1388 * the same object type, ->siglock can't be reinitialized.
1390 * We need to ensure that tsk->sighand is still the same
1391 * after we take the lock, we can race with de_thread() or
1392 * __exit_signal(). In the latter case the next iteration
1393 * must see ->sighand == NULL.
1395 spin_lock_irqsave(&sighand->siglock, *flags);
1396 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1398 spin_unlock_irqrestore(&sighand->siglock, *flags);
1406 * send signal info to all the members of a group
1408 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1409 struct task_struct *p, enum pid_type type)
1414 ret = check_kill_permission(sig, info, p);
1418 ret = do_send_sig_info(sig, info, p, type);
1424 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1425 * control characters do (^C, ^Z etc)
1426 * - the caller must hold at least a readlock on tasklist_lock
1428 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1430 struct task_struct *p = NULL;
1431 int retval, success;
1435 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1436 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1439 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1440 return success ? 0 : retval;
1443 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1446 struct task_struct *p;
1450 p = pid_task(pid, PIDTYPE_PID);
1452 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1454 if (likely(!p || error != -ESRCH))
1458 * The task was unhashed in between, try again. If it
1459 * is dead, pid_task() will return NULL, if we race with
1460 * de_thread() it will find the new leader.
1465 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1469 error = kill_pid_info(sig, info, find_vpid(pid));
1474 static inline bool kill_as_cred_perm(const struct cred *cred,
1475 struct task_struct *target)
1477 const struct cred *pcred = __task_cred(target);
1479 return uid_eq(cred->euid, pcred->suid) ||
1480 uid_eq(cred->euid, pcred->uid) ||
1481 uid_eq(cred->uid, pcred->suid) ||
1482 uid_eq(cred->uid, pcred->uid);
1486 * The usb asyncio usage of siginfo is wrong. The glibc support
1487 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1488 * AKA after the generic fields:
1489 * kernel_pid_t si_pid;
1490 * kernel_uid32_t si_uid;
1491 * sigval_t si_value;
1493 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1494 * after the generic fields is:
1495 * void __user *si_addr;
1497 * This is a practical problem when there is a 64bit big endian kernel
1498 * and a 32bit userspace. As the 32bit address will encoded in the low
1499 * 32bits of the pointer. Those low 32bits will be stored at higher
1500 * address than appear in a 32 bit pointer. So userspace will not
1501 * see the address it was expecting for it's completions.
1503 * There is nothing in the encoding that can allow
1504 * copy_siginfo_to_user32 to detect this confusion of formats, so
1505 * handle this by requiring the caller of kill_pid_usb_asyncio to
1506 * notice when this situration takes place and to store the 32bit
1507 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1510 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1511 struct pid *pid, const struct cred *cred)
1513 struct kernel_siginfo info;
1514 struct task_struct *p;
1515 unsigned long flags;
1518 if (!valid_signal(sig))
1521 clear_siginfo(&info);
1522 info.si_signo = sig;
1523 info.si_errno = errno;
1524 info.si_code = SI_ASYNCIO;
1525 *((sigval_t *)&info.si_pid) = addr;
1528 p = pid_task(pid, PIDTYPE_PID);
1533 if (!kill_as_cred_perm(cred, p)) {
1537 ret = security_task_kill(p, &info, sig, cred);
1542 if (lock_task_sighand(p, &flags)) {
1543 ret = __send_signal(sig, &info, p, PIDTYPE_TGID, false);
1544 unlock_task_sighand(p, &flags);
1552 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1555 * kill_something_info() interprets pid in interesting ways just like kill(2).
1557 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1558 * is probably wrong. Should make it like BSD or SYSV.
1561 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1566 return kill_proc_info(sig, info, pid);
1568 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1572 read_lock(&tasklist_lock);
1574 ret = __kill_pgrp_info(sig, info,
1575 pid ? find_vpid(-pid) : task_pgrp(current));
1577 int retval = 0, count = 0;
1578 struct task_struct * p;
1580 for_each_process(p) {
1581 if (task_pid_vnr(p) > 1 &&
1582 !same_thread_group(p, current)) {
1583 int err = group_send_sig_info(sig, info, p,
1590 ret = count ? retval : -ESRCH;
1592 read_unlock(&tasklist_lock);
1598 * These are for backward compatibility with the rest of the kernel source.
1601 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1604 * Make sure legacy kernel users don't send in bad values
1605 * (normal paths check this in check_kill_permission).
1607 if (!valid_signal(sig))
1610 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1612 EXPORT_SYMBOL(send_sig_info);
1614 #define __si_special(priv) \
1615 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1618 send_sig(int sig, struct task_struct *p, int priv)
1620 return send_sig_info(sig, __si_special(priv), p);
1622 EXPORT_SYMBOL(send_sig);
1624 void force_sig(int sig)
1626 struct kernel_siginfo info;
1628 clear_siginfo(&info);
1629 info.si_signo = sig;
1631 info.si_code = SI_KERNEL;
1634 force_sig_info(&info);
1636 EXPORT_SYMBOL(force_sig);
1639 * When things go south during signal handling, we
1640 * will force a SIGSEGV. And if the signal that caused
1641 * the problem was already a SIGSEGV, we'll want to
1642 * make sure we don't even try to deliver the signal..
1644 void force_sigsegv(int sig)
1646 struct task_struct *p = current;
1648 if (sig == SIGSEGV) {
1649 unsigned long flags;
1650 spin_lock_irqsave(&p->sighand->siglock, flags);
1651 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1652 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1657 int force_sig_fault_to_task(int sig, int code, void __user *addr
1658 ___ARCH_SI_TRAPNO(int trapno)
1659 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1660 , struct task_struct *t)
1662 struct kernel_siginfo info;
1664 clear_siginfo(&info);
1665 info.si_signo = sig;
1667 info.si_code = code;
1668 info.si_addr = addr;
1669 #ifdef __ARCH_SI_TRAPNO
1670 info.si_trapno = trapno;
1674 info.si_flags = flags;
1677 return force_sig_info_to_task(&info, t);
1680 int force_sig_fault(int sig, int code, void __user *addr
1681 ___ARCH_SI_TRAPNO(int trapno)
1682 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1684 return force_sig_fault_to_task(sig, code, addr
1685 ___ARCH_SI_TRAPNO(trapno)
1686 ___ARCH_SI_IA64(imm, flags, isr), current);
1689 int send_sig_fault(int sig, int code, void __user *addr
1690 ___ARCH_SI_TRAPNO(int trapno)
1691 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1692 , struct task_struct *t)
1694 struct kernel_siginfo info;
1696 clear_siginfo(&info);
1697 info.si_signo = sig;
1699 info.si_code = code;
1700 info.si_addr = addr;
1701 #ifdef __ARCH_SI_TRAPNO
1702 info.si_trapno = trapno;
1706 info.si_flags = flags;
1709 return send_sig_info(info.si_signo, &info, t);
1712 int force_sig_mceerr(int code, void __user *addr, short lsb)
1714 struct kernel_siginfo info;
1716 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1717 clear_siginfo(&info);
1718 info.si_signo = SIGBUS;
1720 info.si_code = code;
1721 info.si_addr = addr;
1722 info.si_addr_lsb = lsb;
1723 return force_sig_info(&info);
1726 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1728 struct kernel_siginfo info;
1730 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1731 clear_siginfo(&info);
1732 info.si_signo = SIGBUS;
1734 info.si_code = code;
1735 info.si_addr = addr;
1736 info.si_addr_lsb = lsb;
1737 return send_sig_info(info.si_signo, &info, t);
1739 EXPORT_SYMBOL(send_sig_mceerr);
1741 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1743 struct kernel_siginfo info;
1745 clear_siginfo(&info);
1746 info.si_signo = SIGSEGV;
1748 info.si_code = SEGV_BNDERR;
1749 info.si_addr = addr;
1750 info.si_lower = lower;
1751 info.si_upper = upper;
1752 return force_sig_info(&info);
1756 int force_sig_pkuerr(void __user *addr, u32 pkey)
1758 struct kernel_siginfo info;
1760 clear_siginfo(&info);
1761 info.si_signo = SIGSEGV;
1763 info.si_code = SEGV_PKUERR;
1764 info.si_addr = addr;
1765 info.si_pkey = pkey;
1766 return force_sig_info(&info);
1770 /* For the crazy architectures that include trap information in
1771 * the errno field, instead of an actual errno value.
1773 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1775 struct kernel_siginfo info;
1777 clear_siginfo(&info);
1778 info.si_signo = SIGTRAP;
1779 info.si_errno = errno;
1780 info.si_code = TRAP_HWBKPT;
1781 info.si_addr = addr;
1782 return force_sig_info(&info);
1785 int kill_pgrp(struct pid *pid, int sig, int priv)
1789 read_lock(&tasklist_lock);
1790 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1791 read_unlock(&tasklist_lock);
1795 EXPORT_SYMBOL(kill_pgrp);
1797 int kill_pid(struct pid *pid, int sig, int priv)
1799 return kill_pid_info(sig, __si_special(priv), pid);
1801 EXPORT_SYMBOL(kill_pid);
1804 * These functions support sending signals using preallocated sigqueue
1805 * structures. This is needed "because realtime applications cannot
1806 * afford to lose notifications of asynchronous events, like timer
1807 * expirations or I/O completions". In the case of POSIX Timers
1808 * we allocate the sigqueue structure from the timer_create. If this
1809 * allocation fails we are able to report the failure to the application
1810 * with an EAGAIN error.
1812 struct sigqueue *sigqueue_alloc(void)
1814 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1817 q->flags |= SIGQUEUE_PREALLOC;
1822 void sigqueue_free(struct sigqueue *q)
1824 unsigned long flags;
1825 spinlock_t *lock = ¤t->sighand->siglock;
1827 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1829 * We must hold ->siglock while testing q->list
1830 * to serialize with collect_signal() or with
1831 * __exit_signal()->flush_sigqueue().
1833 spin_lock_irqsave(lock, flags);
1834 q->flags &= ~SIGQUEUE_PREALLOC;
1836 * If it is queued it will be freed when dequeued,
1837 * like the "regular" sigqueue.
1839 if (!list_empty(&q->list))
1841 spin_unlock_irqrestore(lock, flags);
1847 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1849 int sig = q->info.si_signo;
1850 struct sigpending *pending;
1851 struct task_struct *t;
1852 unsigned long flags;
1855 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1859 t = pid_task(pid, type);
1860 if (!t || !likely(lock_task_sighand(t, &flags)))
1863 ret = 1; /* the signal is ignored */
1864 result = TRACE_SIGNAL_IGNORED;
1865 if (!prepare_signal(sig, t, false))
1869 if (unlikely(!list_empty(&q->list))) {
1871 * If an SI_TIMER entry is already queue just increment
1872 * the overrun count.
1874 BUG_ON(q->info.si_code != SI_TIMER);
1875 q->info.si_overrun++;
1876 result = TRACE_SIGNAL_ALREADY_PENDING;
1879 q->info.si_overrun = 0;
1881 signalfd_notify(t, sig);
1882 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1883 list_add_tail(&q->list, &pending->list);
1884 sigaddset(&pending->signal, sig);
1885 complete_signal(sig, t, type);
1886 result = TRACE_SIGNAL_DELIVERED;
1888 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
1889 unlock_task_sighand(t, &flags);
1895 static void do_notify_pidfd(struct task_struct *task)
1899 WARN_ON(task->exit_state == 0);
1900 pid = task_pid(task);
1901 wake_up_all(&pid->wait_pidfd);
1905 * Let a parent know about the death of a child.
1906 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1908 * Returns true if our parent ignored us and so we've switched to
1911 bool do_notify_parent(struct task_struct *tsk, int sig)
1913 struct kernel_siginfo info;
1914 unsigned long flags;
1915 struct sighand_struct *psig;
1916 bool autoreap = false;
1921 /* do_notify_parent_cldstop should have been called instead. */
1922 BUG_ON(task_is_stopped_or_traced(tsk));
1924 BUG_ON(!tsk->ptrace &&
1925 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1927 /* Wake up all pidfd waiters */
1928 do_notify_pidfd(tsk);
1930 if (sig != SIGCHLD) {
1932 * This is only possible if parent == real_parent.
1933 * Check if it has changed security domain.
1935 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
1939 clear_siginfo(&info);
1940 info.si_signo = sig;
1943 * We are under tasklist_lock here so our parent is tied to
1944 * us and cannot change.
1946 * task_active_pid_ns will always return the same pid namespace
1947 * until a task passes through release_task.
1949 * write_lock() currently calls preempt_disable() which is the
1950 * same as rcu_read_lock(), but according to Oleg, this is not
1951 * correct to rely on this
1954 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1955 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1959 task_cputime(tsk, &utime, &stime);
1960 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
1961 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
1963 info.si_status = tsk->exit_code & 0x7f;
1964 if (tsk->exit_code & 0x80)
1965 info.si_code = CLD_DUMPED;
1966 else if (tsk->exit_code & 0x7f)
1967 info.si_code = CLD_KILLED;
1969 info.si_code = CLD_EXITED;
1970 info.si_status = tsk->exit_code >> 8;
1973 psig = tsk->parent->sighand;
1974 spin_lock_irqsave(&psig->siglock, flags);
1975 if (!tsk->ptrace && sig == SIGCHLD &&
1976 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1977 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1979 * We are exiting and our parent doesn't care. POSIX.1
1980 * defines special semantics for setting SIGCHLD to SIG_IGN
1981 * or setting the SA_NOCLDWAIT flag: we should be reaped
1982 * automatically and not left for our parent's wait4 call.
1983 * Rather than having the parent do it as a magic kind of
1984 * signal handler, we just set this to tell do_exit that we
1985 * can be cleaned up without becoming a zombie. Note that
1986 * we still call __wake_up_parent in this case, because a
1987 * blocked sys_wait4 might now return -ECHILD.
1989 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1990 * is implementation-defined: we do (if you don't want
1991 * it, just use SIG_IGN instead).
1994 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1998 * Send with __send_signal as si_pid and si_uid are in the
1999 * parent's namespaces.
2001 if (valid_signal(sig) && sig)
2002 __send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false);
2003 __wake_up_parent(tsk, tsk->parent);
2004 spin_unlock_irqrestore(&psig->siglock, flags);
2010 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2011 * @tsk: task reporting the state change
2012 * @for_ptracer: the notification is for ptracer
2013 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2015 * Notify @tsk's parent that the stopped/continued state has changed. If
2016 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2017 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2020 * Must be called with tasklist_lock at least read locked.
2022 static void do_notify_parent_cldstop(struct task_struct *tsk,
2023 bool for_ptracer, int why)
2025 struct kernel_siginfo info;
2026 unsigned long flags;
2027 struct task_struct *parent;
2028 struct sighand_struct *sighand;
2032 parent = tsk->parent;
2034 tsk = tsk->group_leader;
2035 parent = tsk->real_parent;
2038 clear_siginfo(&info);
2039 info.si_signo = SIGCHLD;
2042 * see comment in do_notify_parent() about the following 4 lines
2045 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2046 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2049 task_cputime(tsk, &utime, &stime);
2050 info.si_utime = nsec_to_clock_t(utime);
2051 info.si_stime = nsec_to_clock_t(stime);
2056 info.si_status = SIGCONT;
2059 info.si_status = tsk->signal->group_exit_code & 0x7f;
2062 info.si_status = tsk->exit_code & 0x7f;
2068 sighand = parent->sighand;
2069 spin_lock_irqsave(&sighand->siglock, flags);
2070 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2071 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2072 __group_send_sig_info(SIGCHLD, &info, parent);
2074 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2076 __wake_up_parent(tsk, parent);
2077 spin_unlock_irqrestore(&sighand->siglock, flags);
2080 static inline bool may_ptrace_stop(void)
2082 if (!likely(current->ptrace))
2085 * Are we in the middle of do_coredump?
2086 * If so and our tracer is also part of the coredump stopping
2087 * is a deadlock situation, and pointless because our tracer
2088 * is dead so don't allow us to stop.
2089 * If SIGKILL was already sent before the caller unlocked
2090 * ->siglock we must see ->core_state != NULL. Otherwise it
2091 * is safe to enter schedule().
2093 * This is almost outdated, a task with the pending SIGKILL can't
2094 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2095 * after SIGKILL was already dequeued.
2097 if (unlikely(current->mm->core_state) &&
2098 unlikely(current->mm == current->parent->mm))
2105 * Return non-zero if there is a SIGKILL that should be waking us up.
2106 * Called with the siglock held.
2108 static bool sigkill_pending(struct task_struct *tsk)
2110 return sigismember(&tsk->pending.signal, SIGKILL) ||
2111 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
2115 * This must be called with current->sighand->siglock held.
2117 * This should be the path for all ptrace stops.
2118 * We always set current->last_siginfo while stopped here.
2119 * That makes it a way to test a stopped process for
2120 * being ptrace-stopped vs being job-control-stopped.
2122 * If we actually decide not to stop at all because the tracer
2123 * is gone, we keep current->exit_code unless clear_code.
2125 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2126 __releases(¤t->sighand->siglock)
2127 __acquires(¤t->sighand->siglock)
2129 bool gstop_done = false;
2131 if (arch_ptrace_stop_needed(exit_code, info)) {
2133 * The arch code has something special to do before a
2134 * ptrace stop. This is allowed to block, e.g. for faults
2135 * on user stack pages. We can't keep the siglock while
2136 * calling arch_ptrace_stop, so we must release it now.
2137 * To preserve proper semantics, we must do this before
2138 * any signal bookkeeping like checking group_stop_count.
2139 * Meanwhile, a SIGKILL could come in before we retake the
2140 * siglock. That must prevent us from sleeping in TASK_TRACED.
2141 * So after regaining the lock, we must check for SIGKILL.
2143 spin_unlock_irq(¤t->sighand->siglock);
2144 arch_ptrace_stop(exit_code, info);
2145 spin_lock_irq(¤t->sighand->siglock);
2146 if (sigkill_pending(current))
2150 set_special_state(TASK_TRACED);
2153 * We're committing to trapping. TRACED should be visible before
2154 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2155 * Also, transition to TRACED and updates to ->jobctl should be
2156 * atomic with respect to siglock and should be done after the arch
2157 * hook as siglock is released and regrabbed across it.
2162 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2164 * set_current_state() smp_wmb();
2166 * wait_task_stopped()
2167 * task_stopped_code()
2168 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2172 current->last_siginfo = info;
2173 current->exit_code = exit_code;
2176 * If @why is CLD_STOPPED, we're trapping to participate in a group
2177 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2178 * across siglock relocks since INTERRUPT was scheduled, PENDING
2179 * could be clear now. We act as if SIGCONT is received after
2180 * TASK_TRACED is entered - ignore it.
2182 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2183 gstop_done = task_participate_group_stop(current);
2185 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2186 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2187 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2188 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2190 /* entering a trap, clear TRAPPING */
2191 task_clear_jobctl_trapping(current);
2193 spin_unlock_irq(¤t->sighand->siglock);
2194 read_lock(&tasklist_lock);
2195 if (may_ptrace_stop()) {
2197 * Notify parents of the stop.
2199 * While ptraced, there are two parents - the ptracer and
2200 * the real_parent of the group_leader. The ptracer should
2201 * know about every stop while the real parent is only
2202 * interested in the completion of group stop. The states
2203 * for the two don't interact with each other. Notify
2204 * separately unless they're gonna be duplicates.
2206 do_notify_parent_cldstop(current, true, why);
2207 if (gstop_done && ptrace_reparented(current))
2208 do_notify_parent_cldstop(current, false, why);
2211 * Don't want to allow preemption here, because
2212 * sys_ptrace() needs this task to be inactive.
2214 * XXX: implement read_unlock_no_resched().
2217 read_unlock(&tasklist_lock);
2218 cgroup_enter_frozen();
2219 preempt_enable_no_resched();
2220 freezable_schedule();
2221 cgroup_leave_frozen(true);
2224 * By the time we got the lock, our tracer went away.
2225 * Don't drop the lock yet, another tracer may come.
2227 * If @gstop_done, the ptracer went away between group stop
2228 * completion and here. During detach, it would have set
2229 * JOBCTL_STOP_PENDING on us and we'll re-enter
2230 * TASK_STOPPED in do_signal_stop() on return, so notifying
2231 * the real parent of the group stop completion is enough.
2234 do_notify_parent_cldstop(current, false, why);
2236 /* tasklist protects us from ptrace_freeze_traced() */
2237 __set_current_state(TASK_RUNNING);
2239 current->exit_code = 0;
2240 read_unlock(&tasklist_lock);
2244 * We are back. Now reacquire the siglock before touching
2245 * last_siginfo, so that we are sure to have synchronized with
2246 * any signal-sending on another CPU that wants to examine it.
2248 spin_lock_irq(¤t->sighand->siglock);
2249 current->last_siginfo = NULL;
2251 /* LISTENING can be set only during STOP traps, clear it */
2252 current->jobctl &= ~JOBCTL_LISTENING;
2255 * Queued signals ignored us while we were stopped for tracing.
2256 * So check for any that we should take before resuming user mode.
2257 * This sets TIF_SIGPENDING, but never clears it.
2259 recalc_sigpending_tsk(current);
2262 static void ptrace_do_notify(int signr, int exit_code, int why)
2264 kernel_siginfo_t info;
2266 clear_siginfo(&info);
2267 info.si_signo = signr;
2268 info.si_code = exit_code;
2269 info.si_pid = task_pid_vnr(current);
2270 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2272 /* Let the debugger run. */
2273 ptrace_stop(exit_code, why, 1, &info);
2276 void ptrace_notify(int exit_code)
2278 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2279 if (unlikely(current->task_works))
2282 spin_lock_irq(¤t->sighand->siglock);
2283 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2284 spin_unlock_irq(¤t->sighand->siglock);
2288 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2289 * @signr: signr causing group stop if initiating
2291 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2292 * and participate in it. If already set, participate in the existing
2293 * group stop. If participated in a group stop (and thus slept), %true is
2294 * returned with siglock released.
2296 * If ptraced, this function doesn't handle stop itself. Instead,
2297 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2298 * untouched. The caller must ensure that INTERRUPT trap handling takes
2299 * places afterwards.
2302 * Must be called with @current->sighand->siglock held, which is released
2306 * %false if group stop is already cancelled or ptrace trap is scheduled.
2307 * %true if participated in group stop.
2309 static bool do_signal_stop(int signr)
2310 __releases(¤t->sighand->siglock)
2312 struct signal_struct *sig = current->signal;
2314 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2315 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2316 struct task_struct *t;
2318 /* signr will be recorded in task->jobctl for retries */
2319 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2321 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2322 unlikely(signal_group_exit(sig)))
2325 * There is no group stop already in progress. We must
2328 * While ptraced, a task may be resumed while group stop is
2329 * still in effect and then receive a stop signal and
2330 * initiate another group stop. This deviates from the
2331 * usual behavior as two consecutive stop signals can't
2332 * cause two group stops when !ptraced. That is why we
2333 * also check !task_is_stopped(t) below.
2335 * The condition can be distinguished by testing whether
2336 * SIGNAL_STOP_STOPPED is already set. Don't generate
2337 * group_exit_code in such case.
2339 * This is not necessary for SIGNAL_STOP_CONTINUED because
2340 * an intervening stop signal is required to cause two
2341 * continued events regardless of ptrace.
2343 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2344 sig->group_exit_code = signr;
2346 sig->group_stop_count = 0;
2348 if (task_set_jobctl_pending(current, signr | gstop))
2349 sig->group_stop_count++;
2352 while_each_thread(current, t) {
2354 * Setting state to TASK_STOPPED for a group
2355 * stop is always done with the siglock held,
2356 * so this check has no races.
2358 if (!task_is_stopped(t) &&
2359 task_set_jobctl_pending(t, signr | gstop)) {
2360 sig->group_stop_count++;
2361 if (likely(!(t->ptrace & PT_SEIZED)))
2362 signal_wake_up(t, 0);
2364 ptrace_trap_notify(t);
2369 if (likely(!current->ptrace)) {
2373 * If there are no other threads in the group, or if there
2374 * is a group stop in progress and we are the last to stop,
2375 * report to the parent.
2377 if (task_participate_group_stop(current))
2378 notify = CLD_STOPPED;
2380 set_special_state(TASK_STOPPED);
2381 spin_unlock_irq(¤t->sighand->siglock);
2384 * Notify the parent of the group stop completion. Because
2385 * we're not holding either the siglock or tasklist_lock
2386 * here, ptracer may attach inbetween; however, this is for
2387 * group stop and should always be delivered to the real
2388 * parent of the group leader. The new ptracer will get
2389 * its notification when this task transitions into
2393 read_lock(&tasklist_lock);
2394 do_notify_parent_cldstop(current, false, notify);
2395 read_unlock(&tasklist_lock);
2398 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2399 cgroup_enter_frozen();
2400 freezable_schedule();
2404 * While ptraced, group stop is handled by STOP trap.
2405 * Schedule it and let the caller deal with it.
2407 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2413 * do_jobctl_trap - take care of ptrace jobctl traps
2415 * When PT_SEIZED, it's used for both group stop and explicit
2416 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2417 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2418 * the stop signal; otherwise, %SIGTRAP.
2420 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2421 * number as exit_code and no siginfo.
2424 * Must be called with @current->sighand->siglock held, which may be
2425 * released and re-acquired before returning with intervening sleep.
2427 static void do_jobctl_trap(void)
2429 struct signal_struct *signal = current->signal;
2430 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2432 if (current->ptrace & PT_SEIZED) {
2433 if (!signal->group_stop_count &&
2434 !(signal->flags & SIGNAL_STOP_STOPPED))
2436 WARN_ON_ONCE(!signr);
2437 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2440 WARN_ON_ONCE(!signr);
2441 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2442 current->exit_code = 0;
2447 * do_freezer_trap - handle the freezer jobctl trap
2449 * Puts the task into frozen state, if only the task is not about to quit.
2450 * In this case it drops JOBCTL_TRAP_FREEZE.
2453 * Must be called with @current->sighand->siglock held,
2454 * which is always released before returning.
2456 static void do_freezer_trap(void)
2457 __releases(¤t->sighand->siglock)
2460 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2461 * let's make another loop to give it a chance to be handled.
2462 * In any case, we'll return back.
2464 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2465 JOBCTL_TRAP_FREEZE) {
2466 spin_unlock_irq(¤t->sighand->siglock);
2471 * Now we're sure that there is no pending fatal signal and no
2472 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2473 * immediately (if there is a non-fatal signal pending), and
2474 * put the task into sleep.
2476 __set_current_state(TASK_INTERRUPTIBLE);
2477 clear_thread_flag(TIF_SIGPENDING);
2478 spin_unlock_irq(¤t->sighand->siglock);
2479 cgroup_enter_frozen();
2480 freezable_schedule();
2483 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2486 * We do not check sig_kernel_stop(signr) but set this marker
2487 * unconditionally because we do not know whether debugger will
2488 * change signr. This flag has no meaning unless we are going
2489 * to stop after return from ptrace_stop(). In this case it will
2490 * be checked in do_signal_stop(), we should only stop if it was
2491 * not cleared by SIGCONT while we were sleeping. See also the
2492 * comment in dequeue_signal().
2494 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2495 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2497 /* We're back. Did the debugger cancel the sig? */
2498 signr = current->exit_code;
2502 current->exit_code = 0;
2505 * Update the siginfo structure if the signal has
2506 * changed. If the debugger wanted something
2507 * specific in the siginfo structure then it should
2508 * have updated *info via PTRACE_SETSIGINFO.
2510 if (signr != info->si_signo) {
2511 clear_siginfo(info);
2512 info->si_signo = signr;
2514 info->si_code = SI_USER;
2516 info->si_pid = task_pid_vnr(current->parent);
2517 info->si_uid = from_kuid_munged(current_user_ns(),
2518 task_uid(current->parent));
2522 /* If the (new) signal is now blocked, requeue it. */
2523 if (sigismember(¤t->blocked, signr)) {
2524 send_signal(signr, info, current, PIDTYPE_PID);
2531 static void hide_si_addr_tag_bits(struct ksignal *ksig)
2533 switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
2535 case SIL_FAULT_MCEERR:
2536 case SIL_FAULT_BNDERR:
2537 case SIL_FAULT_PKUERR:
2538 ksig->info.si_addr = arch_untagged_si_addr(
2539 ksig->info.si_addr, ksig->sig, ksig->info.si_code);
2551 bool get_signal(struct ksignal *ksig)
2553 struct sighand_struct *sighand = current->sighand;
2554 struct signal_struct *signal = current->signal;
2557 if (unlikely(current->task_works))
2561 * For non-generic architectures, check for TIF_NOTIFY_SIGNAL so
2562 * that the arch handlers don't all have to do it. If we get here
2563 * without TIF_SIGPENDING, just exit after running signal work.
2565 if (!IS_ENABLED(CONFIG_GENERIC_ENTRY)) {
2566 if (test_thread_flag(TIF_NOTIFY_SIGNAL))
2567 tracehook_notify_signal();
2568 if (!task_sigpending(current))
2572 if (unlikely(uprobe_deny_signal()))
2576 * Do this once, we can't return to user-mode if freezing() == T.
2577 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2578 * thus do not need another check after return.
2583 spin_lock_irq(&sighand->siglock);
2586 * Every stopped thread goes here after wakeup. Check to see if
2587 * we should notify the parent, prepare_signal(SIGCONT) encodes
2588 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2590 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2593 if (signal->flags & SIGNAL_CLD_CONTINUED)
2594 why = CLD_CONTINUED;
2598 signal->flags &= ~SIGNAL_CLD_MASK;
2600 spin_unlock_irq(&sighand->siglock);
2603 * Notify the parent that we're continuing. This event is
2604 * always per-process and doesn't make whole lot of sense
2605 * for ptracers, who shouldn't consume the state via
2606 * wait(2) either, but, for backward compatibility, notify
2607 * the ptracer of the group leader too unless it's gonna be
2610 read_lock(&tasklist_lock);
2611 do_notify_parent_cldstop(current, false, why);
2613 if (ptrace_reparented(current->group_leader))
2614 do_notify_parent_cldstop(current->group_leader,
2616 read_unlock(&tasklist_lock);
2621 /* Has this task already been marked for death? */
2622 if (signal_group_exit(signal)) {
2623 ksig->info.si_signo = signr = SIGKILL;
2624 sigdelset(¤t->pending.signal, SIGKILL);
2625 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2626 &sighand->action[SIGKILL - 1]);
2627 recalc_sigpending();
2632 struct k_sigaction *ka;
2634 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2638 if (unlikely(current->jobctl &
2639 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2640 if (current->jobctl & JOBCTL_TRAP_MASK) {
2642 spin_unlock_irq(&sighand->siglock);
2643 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2650 * If the task is leaving the frozen state, let's update
2651 * cgroup counters and reset the frozen bit.
2653 if (unlikely(cgroup_task_frozen(current))) {
2654 spin_unlock_irq(&sighand->siglock);
2655 cgroup_leave_frozen(false);
2660 * Signals generated by the execution of an instruction
2661 * need to be delivered before any other pending signals
2662 * so that the instruction pointer in the signal stack
2663 * frame points to the faulting instruction.
2665 signr = dequeue_synchronous_signal(&ksig->info);
2667 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2670 break; /* will return 0 */
2672 if (unlikely(current->ptrace) && signr != SIGKILL) {
2673 signr = ptrace_signal(signr, &ksig->info);
2678 ka = &sighand->action[signr-1];
2680 /* Trace actually delivered signals. */
2681 trace_signal_deliver(signr, &ksig->info, ka);
2683 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2685 if (ka->sa.sa_handler != SIG_DFL) {
2686 /* Run the handler. */
2689 if (ka->sa.sa_flags & SA_ONESHOT)
2690 ka->sa.sa_handler = SIG_DFL;
2692 break; /* will return non-zero "signr" value */
2696 * Now we are doing the default action for this signal.
2698 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2702 * Global init gets no signals it doesn't want.
2703 * Container-init gets no signals it doesn't want from same
2706 * Note that if global/container-init sees a sig_kernel_only()
2707 * signal here, the signal must have been generated internally
2708 * or must have come from an ancestor namespace. In either
2709 * case, the signal cannot be dropped.
2711 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2712 !sig_kernel_only(signr))
2715 if (sig_kernel_stop(signr)) {
2717 * The default action is to stop all threads in
2718 * the thread group. The job control signals
2719 * do nothing in an orphaned pgrp, but SIGSTOP
2720 * always works. Note that siglock needs to be
2721 * dropped during the call to is_orphaned_pgrp()
2722 * because of lock ordering with tasklist_lock.
2723 * This allows an intervening SIGCONT to be posted.
2724 * We need to check for that and bail out if necessary.
2726 if (signr != SIGSTOP) {
2727 spin_unlock_irq(&sighand->siglock);
2729 /* signals can be posted during this window */
2731 if (is_current_pgrp_orphaned())
2734 spin_lock_irq(&sighand->siglock);
2737 if (likely(do_signal_stop(ksig->info.si_signo))) {
2738 /* It released the siglock. */
2743 * We didn't actually stop, due to a race
2744 * with SIGCONT or something like that.
2750 spin_unlock_irq(&sighand->siglock);
2751 if (unlikely(cgroup_task_frozen(current)))
2752 cgroup_leave_frozen(true);
2755 * Anything else is fatal, maybe with a core dump.
2757 current->flags |= PF_SIGNALED;
2759 if (sig_kernel_coredump(signr)) {
2760 if (print_fatal_signals)
2761 print_fatal_signal(ksig->info.si_signo);
2762 proc_coredump_connector(current);
2764 * If it was able to dump core, this kills all
2765 * other threads in the group and synchronizes with
2766 * their demise. If we lost the race with another
2767 * thread getting here, it set group_exit_code
2768 * first and our do_group_exit call below will use
2769 * that value and ignore the one we pass it.
2771 do_coredump(&ksig->info);
2775 * Death signals, no core dump.
2777 do_group_exit(ksig->info.si_signo);
2780 spin_unlock_irq(&sighand->siglock);
2784 if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
2785 hide_si_addr_tag_bits(ksig);
2787 return ksig->sig > 0;
2791 * signal_delivered -
2792 * @ksig: kernel signal struct
2793 * @stepping: nonzero if debugger single-step or block-step in use
2795 * This function should be called when a signal has successfully been
2796 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2797 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2798 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2800 static void signal_delivered(struct ksignal *ksig, int stepping)
2804 /* A signal was successfully delivered, and the
2805 saved sigmask was stored on the signal frame,
2806 and will be restored by sigreturn. So we can
2807 simply clear the restore sigmask flag. */
2808 clear_restore_sigmask();
2810 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2811 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2812 sigaddset(&blocked, ksig->sig);
2813 set_current_blocked(&blocked);
2814 tracehook_signal_handler(stepping);
2817 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2820 force_sigsegv(ksig->sig);
2822 signal_delivered(ksig, stepping);
2826 * It could be that complete_signal() picked us to notify about the
2827 * group-wide signal. Other threads should be notified now to take
2828 * the shared signals in @which since we will not.
2830 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2833 struct task_struct *t;
2835 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2836 if (sigisemptyset(&retarget))
2840 while_each_thread(tsk, t) {
2841 if (t->flags & PF_EXITING)
2844 if (!has_pending_signals(&retarget, &t->blocked))
2846 /* Remove the signals this thread can handle. */
2847 sigandsets(&retarget, &retarget, &t->blocked);
2849 if (!task_sigpending(t))
2850 signal_wake_up(t, 0);
2852 if (sigisemptyset(&retarget))
2857 void exit_signals(struct task_struct *tsk)
2863 * @tsk is about to have PF_EXITING set - lock out users which
2864 * expect stable threadgroup.
2866 cgroup_threadgroup_change_begin(tsk);
2868 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2869 tsk->flags |= PF_EXITING;
2870 cgroup_threadgroup_change_end(tsk);
2874 spin_lock_irq(&tsk->sighand->siglock);
2876 * From now this task is not visible for group-wide signals,
2877 * see wants_signal(), do_signal_stop().
2879 tsk->flags |= PF_EXITING;
2881 cgroup_threadgroup_change_end(tsk);
2883 if (!task_sigpending(tsk))
2886 unblocked = tsk->blocked;
2887 signotset(&unblocked);
2888 retarget_shared_pending(tsk, &unblocked);
2890 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2891 task_participate_group_stop(tsk))
2892 group_stop = CLD_STOPPED;
2894 spin_unlock_irq(&tsk->sighand->siglock);
2897 * If group stop has completed, deliver the notification. This
2898 * should always go to the real parent of the group leader.
2900 if (unlikely(group_stop)) {
2901 read_lock(&tasklist_lock);
2902 do_notify_parent_cldstop(tsk, false, group_stop);
2903 read_unlock(&tasklist_lock);
2908 * System call entry points.
2912 * sys_restart_syscall - restart a system call
2914 SYSCALL_DEFINE0(restart_syscall)
2916 struct restart_block *restart = ¤t->restart_block;
2917 return restart->fn(restart);
2920 long do_no_restart_syscall(struct restart_block *param)
2925 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2927 if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
2928 sigset_t newblocked;
2929 /* A set of now blocked but previously unblocked signals. */
2930 sigandnsets(&newblocked, newset, ¤t->blocked);
2931 retarget_shared_pending(tsk, &newblocked);
2933 tsk->blocked = *newset;
2934 recalc_sigpending();
2938 * set_current_blocked - change current->blocked mask
2941 * It is wrong to change ->blocked directly, this helper should be used
2942 * to ensure the process can't miss a shared signal we are going to block.
2944 void set_current_blocked(sigset_t *newset)
2946 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2947 __set_current_blocked(newset);
2950 void __set_current_blocked(const sigset_t *newset)
2952 struct task_struct *tsk = current;
2955 * In case the signal mask hasn't changed, there is nothing we need
2956 * to do. The current->blocked shouldn't be modified by other task.
2958 if (sigequalsets(&tsk->blocked, newset))
2961 spin_lock_irq(&tsk->sighand->siglock);
2962 __set_task_blocked(tsk, newset);
2963 spin_unlock_irq(&tsk->sighand->siglock);
2967 * This is also useful for kernel threads that want to temporarily
2968 * (or permanently) block certain signals.
2970 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2971 * interface happily blocks "unblockable" signals like SIGKILL
2974 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2976 struct task_struct *tsk = current;
2979 /* Lockless, only current can change ->blocked, never from irq */
2981 *oldset = tsk->blocked;
2985 sigorsets(&newset, &tsk->blocked, set);
2988 sigandnsets(&newset, &tsk->blocked, set);
2997 __set_current_blocked(&newset);
3000 EXPORT_SYMBOL(sigprocmask);
3003 * The api helps set app-provided sigmasks.
3005 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
3006 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
3008 * Note that it does set_restore_sigmask() in advance, so it must be always
3009 * paired with restore_saved_sigmask_unless() before return from syscall.
3011 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
3017 if (sigsetsize != sizeof(sigset_t))
3019 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
3022 set_restore_sigmask();
3023 current->saved_sigmask = current->blocked;
3024 set_current_blocked(&kmask);
3029 #ifdef CONFIG_COMPAT
3030 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3037 if (sigsetsize != sizeof(compat_sigset_t))
3039 if (get_compat_sigset(&kmask, umask))
3042 set_restore_sigmask();
3043 current->saved_sigmask = current->blocked;
3044 set_current_blocked(&kmask);
3051 * sys_rt_sigprocmask - change the list of currently blocked signals
3052 * @how: whether to add, remove, or set signals
3053 * @nset: stores pending signals
3054 * @oset: previous value of signal mask if non-null
3055 * @sigsetsize: size of sigset_t type
3057 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3058 sigset_t __user *, oset, size_t, sigsetsize)
3060 sigset_t old_set, new_set;
3063 /* XXX: Don't preclude handling different sized sigset_t's. */
3064 if (sigsetsize != sizeof(sigset_t))
3067 old_set = current->blocked;
3070 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3072 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3074 error = sigprocmask(how, &new_set, NULL);
3080 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3087 #ifdef CONFIG_COMPAT
3088 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3089 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3091 sigset_t old_set = current->blocked;
3093 /* XXX: Don't preclude handling different sized sigset_t's. */
3094 if (sigsetsize != sizeof(sigset_t))
3100 if (get_compat_sigset(&new_set, nset))
3102 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3104 error = sigprocmask(how, &new_set, NULL);
3108 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3112 static void do_sigpending(sigset_t *set)
3114 spin_lock_irq(¤t->sighand->siglock);
3115 sigorsets(set, ¤t->pending.signal,
3116 ¤t->signal->shared_pending.signal);
3117 spin_unlock_irq(¤t->sighand->siglock);
3119 /* Outside the lock because only this thread touches it. */
3120 sigandsets(set, ¤t->blocked, set);
3124 * sys_rt_sigpending - examine a pending signal that has been raised
3126 * @uset: stores pending signals
3127 * @sigsetsize: size of sigset_t type or larger
3129 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3133 if (sigsetsize > sizeof(*uset))
3136 do_sigpending(&set);
3138 if (copy_to_user(uset, &set, sigsetsize))
3144 #ifdef CONFIG_COMPAT
3145 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3146 compat_size_t, sigsetsize)
3150 if (sigsetsize > sizeof(*uset))
3153 do_sigpending(&set);
3155 return put_compat_sigset(uset, &set, sigsetsize);
3159 static const struct {
3160 unsigned char limit, layout;
3162 [SIGILL] = { NSIGILL, SIL_FAULT },
3163 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3164 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3165 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3166 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3168 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3170 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3171 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3172 [SIGSYS] = { NSIGSYS, SIL_SYS },
3175 static bool known_siginfo_layout(unsigned sig, int si_code)
3177 if (si_code == SI_KERNEL)
3179 else if ((si_code > SI_USER)) {
3180 if (sig_specific_sicodes(sig)) {
3181 if (si_code <= sig_sicodes[sig].limit)
3184 else if (si_code <= NSIGPOLL)
3187 else if (si_code >= SI_DETHREAD)
3189 else if (si_code == SI_ASYNCNL)
3194 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3196 enum siginfo_layout layout = SIL_KILL;
3197 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3198 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3199 (si_code <= sig_sicodes[sig].limit)) {
3200 layout = sig_sicodes[sig].layout;
3201 /* Handle the exceptions */
3202 if ((sig == SIGBUS) &&
3203 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3204 layout = SIL_FAULT_MCEERR;
3205 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3206 layout = SIL_FAULT_BNDERR;
3208 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3209 layout = SIL_FAULT_PKUERR;
3212 else if (si_code <= NSIGPOLL)
3215 if (si_code == SI_TIMER)
3217 else if (si_code == SI_SIGIO)
3219 else if (si_code < 0)
3225 static inline char __user *si_expansion(const siginfo_t __user *info)
3227 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3230 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3232 char __user *expansion = si_expansion(to);
3233 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3235 if (clear_user(expansion, SI_EXPANSION_SIZE))
3240 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3241 const siginfo_t __user *from)
3243 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3244 char __user *expansion = si_expansion(from);
3245 char buf[SI_EXPANSION_SIZE];
3248 * An unknown si_code might need more than
3249 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3250 * extra bytes are 0. This guarantees copy_siginfo_to_user
3251 * will return this data to userspace exactly.
3253 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3255 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3263 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3264 const siginfo_t __user *from)
3266 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3268 to->si_signo = signo;
3269 return post_copy_siginfo_from_user(to, from);
3272 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3274 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3276 return post_copy_siginfo_from_user(to, from);
3279 #ifdef CONFIG_COMPAT
3281 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3282 * @to: compat siginfo destination
3283 * @from: kernel siginfo source
3285 * Note: This function does not work properly for the SIGCHLD on x32, but
3286 * fortunately it doesn't have to. The only valid callers for this function are
3287 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3288 * The latter does not care because SIGCHLD will never cause a coredump.
3290 void copy_siginfo_to_external32(struct compat_siginfo *to,
3291 const struct kernel_siginfo *from)
3293 memset(to, 0, sizeof(*to));
3295 to->si_signo = from->si_signo;
3296 to->si_errno = from->si_errno;
3297 to->si_code = from->si_code;
3298 switch(siginfo_layout(from->si_signo, from->si_code)) {
3300 to->si_pid = from->si_pid;
3301 to->si_uid = from->si_uid;
3304 to->si_tid = from->si_tid;
3305 to->si_overrun = from->si_overrun;
3306 to->si_int = from->si_int;
3309 to->si_band = from->si_band;
3310 to->si_fd = from->si_fd;
3313 to->si_addr = ptr_to_compat(from->si_addr);
3314 #ifdef __ARCH_SI_TRAPNO
3315 to->si_trapno = from->si_trapno;
3318 case SIL_FAULT_MCEERR:
3319 to->si_addr = ptr_to_compat(from->si_addr);
3320 #ifdef __ARCH_SI_TRAPNO
3321 to->si_trapno = from->si_trapno;
3323 to->si_addr_lsb = from->si_addr_lsb;
3325 case SIL_FAULT_BNDERR:
3326 to->si_addr = ptr_to_compat(from->si_addr);
3327 #ifdef __ARCH_SI_TRAPNO
3328 to->si_trapno = from->si_trapno;
3330 to->si_lower = ptr_to_compat(from->si_lower);
3331 to->si_upper = ptr_to_compat(from->si_upper);
3333 case SIL_FAULT_PKUERR:
3334 to->si_addr = ptr_to_compat(from->si_addr);
3335 #ifdef __ARCH_SI_TRAPNO
3336 to->si_trapno = from->si_trapno;
3338 to->si_pkey = from->si_pkey;
3341 to->si_pid = from->si_pid;
3342 to->si_uid = from->si_uid;
3343 to->si_status = from->si_status;
3344 to->si_utime = from->si_utime;
3345 to->si_stime = from->si_stime;
3348 to->si_pid = from->si_pid;
3349 to->si_uid = from->si_uid;
3350 to->si_int = from->si_int;
3353 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3354 to->si_syscall = from->si_syscall;
3355 to->si_arch = from->si_arch;
3360 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3361 const struct kernel_siginfo *from)
3363 struct compat_siginfo new;
3365 copy_siginfo_to_external32(&new, from);
3366 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3371 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3372 const struct compat_siginfo *from)
3375 to->si_signo = from->si_signo;
3376 to->si_errno = from->si_errno;
3377 to->si_code = from->si_code;
3378 switch(siginfo_layout(from->si_signo, from->si_code)) {
3380 to->si_pid = from->si_pid;
3381 to->si_uid = from->si_uid;
3384 to->si_tid = from->si_tid;
3385 to->si_overrun = from->si_overrun;
3386 to->si_int = from->si_int;
3389 to->si_band = from->si_band;
3390 to->si_fd = from->si_fd;
3393 to->si_addr = compat_ptr(from->si_addr);
3394 #ifdef __ARCH_SI_TRAPNO
3395 to->si_trapno = from->si_trapno;
3398 case SIL_FAULT_MCEERR:
3399 to->si_addr = compat_ptr(from->si_addr);
3400 #ifdef __ARCH_SI_TRAPNO
3401 to->si_trapno = from->si_trapno;
3403 to->si_addr_lsb = from->si_addr_lsb;
3405 case SIL_FAULT_BNDERR:
3406 to->si_addr = compat_ptr(from->si_addr);
3407 #ifdef __ARCH_SI_TRAPNO
3408 to->si_trapno = from->si_trapno;
3410 to->si_lower = compat_ptr(from->si_lower);
3411 to->si_upper = compat_ptr(from->si_upper);
3413 case SIL_FAULT_PKUERR:
3414 to->si_addr = compat_ptr(from->si_addr);
3415 #ifdef __ARCH_SI_TRAPNO
3416 to->si_trapno = from->si_trapno;
3418 to->si_pkey = from->si_pkey;
3421 to->si_pid = from->si_pid;
3422 to->si_uid = from->si_uid;
3423 to->si_status = from->si_status;
3424 #ifdef CONFIG_X86_X32_ABI
3425 if (in_x32_syscall()) {
3426 to->si_utime = from->_sifields._sigchld_x32._utime;
3427 to->si_stime = from->_sifields._sigchld_x32._stime;
3431 to->si_utime = from->si_utime;
3432 to->si_stime = from->si_stime;
3436 to->si_pid = from->si_pid;
3437 to->si_uid = from->si_uid;
3438 to->si_int = from->si_int;
3441 to->si_call_addr = compat_ptr(from->si_call_addr);
3442 to->si_syscall = from->si_syscall;
3443 to->si_arch = from->si_arch;
3449 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3450 const struct compat_siginfo __user *ufrom)
3452 struct compat_siginfo from;
3454 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3457 from.si_signo = signo;
3458 return post_copy_siginfo_from_user32(to, &from);
3461 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3462 const struct compat_siginfo __user *ufrom)
3464 struct compat_siginfo from;
3466 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3469 return post_copy_siginfo_from_user32(to, &from);
3471 #endif /* CONFIG_COMPAT */
3474 * do_sigtimedwait - wait for queued signals specified in @which
3475 * @which: queued signals to wait for
3476 * @info: if non-null, the signal's siginfo is returned here
3477 * @ts: upper bound on process time suspension
3479 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3480 const struct timespec64 *ts)
3482 ktime_t *to = NULL, timeout = KTIME_MAX;
3483 struct task_struct *tsk = current;
3484 sigset_t mask = *which;
3488 if (!timespec64_valid(ts))
3490 timeout = timespec64_to_ktime(*ts);
3495 * Invert the set of allowed signals to get those we want to block.
3497 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3500 spin_lock_irq(&tsk->sighand->siglock);
3501 sig = dequeue_signal(tsk, &mask, info);
3502 if (!sig && timeout) {
3504 * None ready, temporarily unblock those we're interested
3505 * while we are sleeping in so that we'll be awakened when
3506 * they arrive. Unblocking is always fine, we can avoid
3507 * set_current_blocked().
3509 tsk->real_blocked = tsk->blocked;
3510 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3511 recalc_sigpending();
3512 spin_unlock_irq(&tsk->sighand->siglock);
3514 __set_current_state(TASK_INTERRUPTIBLE);
3515 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3517 spin_lock_irq(&tsk->sighand->siglock);
3518 __set_task_blocked(tsk, &tsk->real_blocked);
3519 sigemptyset(&tsk->real_blocked);
3520 sig = dequeue_signal(tsk, &mask, info);
3522 spin_unlock_irq(&tsk->sighand->siglock);
3526 return ret ? -EINTR : -EAGAIN;
3530 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3532 * @uthese: queued signals to wait for
3533 * @uinfo: if non-null, the signal's siginfo is returned here
3534 * @uts: upper bound on process time suspension
3535 * @sigsetsize: size of sigset_t type
3537 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3538 siginfo_t __user *, uinfo,
3539 const struct __kernel_timespec __user *, uts,
3543 struct timespec64 ts;
3544 kernel_siginfo_t info;
3547 /* XXX: Don't preclude handling different sized sigset_t's. */
3548 if (sigsetsize != sizeof(sigset_t))
3551 if (copy_from_user(&these, uthese, sizeof(these)))
3555 if (get_timespec64(&ts, uts))
3559 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3561 if (ret > 0 && uinfo) {
3562 if (copy_siginfo_to_user(uinfo, &info))
3569 #ifdef CONFIG_COMPAT_32BIT_TIME
3570 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3571 siginfo_t __user *, uinfo,
3572 const struct old_timespec32 __user *, uts,
3576 struct timespec64 ts;
3577 kernel_siginfo_t info;
3580 if (sigsetsize != sizeof(sigset_t))
3583 if (copy_from_user(&these, uthese, sizeof(these)))
3587 if (get_old_timespec32(&ts, uts))
3591 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3593 if (ret > 0 && uinfo) {
3594 if (copy_siginfo_to_user(uinfo, &info))
3602 #ifdef CONFIG_COMPAT
3603 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3604 struct compat_siginfo __user *, uinfo,
3605 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3608 struct timespec64 t;
3609 kernel_siginfo_t info;
3612 if (sigsetsize != sizeof(sigset_t))
3615 if (get_compat_sigset(&s, uthese))
3619 if (get_timespec64(&t, uts))
3623 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3625 if (ret > 0 && uinfo) {
3626 if (copy_siginfo_to_user32(uinfo, &info))
3633 #ifdef CONFIG_COMPAT_32BIT_TIME
3634 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3635 struct compat_siginfo __user *, uinfo,
3636 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3639 struct timespec64 t;
3640 kernel_siginfo_t info;
3643 if (sigsetsize != sizeof(sigset_t))
3646 if (get_compat_sigset(&s, uthese))
3650 if (get_old_timespec32(&t, uts))
3654 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3656 if (ret > 0 && uinfo) {
3657 if (copy_siginfo_to_user32(uinfo, &info))
3666 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3668 clear_siginfo(info);
3669 info->si_signo = sig;
3671 info->si_code = SI_USER;
3672 info->si_pid = task_tgid_vnr(current);
3673 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3677 * sys_kill - send a signal to a process
3678 * @pid: the PID of the process
3679 * @sig: signal to be sent
3681 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3683 struct kernel_siginfo info;
3685 prepare_kill_siginfo(sig, &info);
3687 return kill_something_info(sig, &info, pid);
3691 * Verify that the signaler and signalee either are in the same pid namespace
3692 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3695 static bool access_pidfd_pidns(struct pid *pid)
3697 struct pid_namespace *active = task_active_pid_ns(current);
3698 struct pid_namespace *p = ns_of_pid(pid);
3711 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
3712 siginfo_t __user *info)
3714 #ifdef CONFIG_COMPAT
3716 * Avoid hooking up compat syscalls and instead handle necessary
3717 * conversions here. Note, this is a stop-gap measure and should not be
3718 * considered a generic solution.
3720 if (in_compat_syscall())
3721 return copy_siginfo_from_user32(
3722 kinfo, (struct compat_siginfo __user *)info);
3724 return copy_siginfo_from_user(kinfo, info);
3727 static struct pid *pidfd_to_pid(const struct file *file)
3731 pid = pidfd_pid(file);
3735 return tgid_pidfd_to_pid(file);
3739 * sys_pidfd_send_signal - Signal a process through a pidfd
3740 * @pidfd: file descriptor of the process
3741 * @sig: signal to send
3742 * @info: signal info
3743 * @flags: future flags
3745 * The syscall currently only signals via PIDTYPE_PID which covers
3746 * kill(<positive-pid>, <signal>. It does not signal threads or process
3748 * In order to extend the syscall to threads and process groups the @flags
3749 * argument should be used. In essence, the @flags argument will determine
3750 * what is signaled and not the file descriptor itself. Put in other words,
3751 * grouping is a property of the flags argument not a property of the file
3754 * Return: 0 on success, negative errno on failure
3756 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3757 siginfo_t __user *, info, unsigned int, flags)
3762 kernel_siginfo_t kinfo;
3764 /* Enforce flags be set to 0 until we add an extension. */
3772 /* Is this a pidfd? */
3773 pid = pidfd_to_pid(f.file);
3780 if (!access_pidfd_pidns(pid))
3784 ret = copy_siginfo_from_user_any(&kinfo, info);
3789 if (unlikely(sig != kinfo.si_signo))
3792 /* Only allow sending arbitrary signals to yourself. */
3794 if ((task_pid(current) != pid) &&
3795 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3798 prepare_kill_siginfo(sig, &kinfo);
3801 ret = kill_pid_info(sig, &kinfo, pid);
3809 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3811 struct task_struct *p;
3815 p = find_task_by_vpid(pid);
3816 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3817 error = check_kill_permission(sig, info, p);
3819 * The null signal is a permissions and process existence
3820 * probe. No signal is actually delivered.
3822 if (!error && sig) {
3823 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3825 * If lock_task_sighand() failed we pretend the task
3826 * dies after receiving the signal. The window is tiny,
3827 * and the signal is private anyway.
3829 if (unlikely(error == -ESRCH))
3838 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3840 struct kernel_siginfo info;
3842 clear_siginfo(&info);
3843 info.si_signo = sig;
3845 info.si_code = SI_TKILL;
3846 info.si_pid = task_tgid_vnr(current);
3847 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3849 return do_send_specific(tgid, pid, sig, &info);
3853 * sys_tgkill - send signal to one specific thread
3854 * @tgid: the thread group ID of the thread
3855 * @pid: the PID of the thread
3856 * @sig: signal to be sent
3858 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3859 * exists but it's not belonging to the target process anymore. This
3860 * method solves the problem of threads exiting and PIDs getting reused.
3862 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3864 /* This is only valid for single tasks */
3865 if (pid <= 0 || tgid <= 0)
3868 return do_tkill(tgid, pid, sig);
3872 * sys_tkill - send signal to one specific task
3873 * @pid: the PID of the task
3874 * @sig: signal to be sent
3876 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3878 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3880 /* This is only valid for single tasks */
3884 return do_tkill(0, pid, sig);
3887 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3889 /* Not even root can pretend to send signals from the kernel.
3890 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3892 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3893 (task_pid_vnr(current) != pid))
3896 /* POSIX.1b doesn't mention process groups. */
3897 return kill_proc_info(sig, info, pid);
3901 * sys_rt_sigqueueinfo - send signal information to a signal
3902 * @pid: the PID of the thread
3903 * @sig: signal to be sent
3904 * @uinfo: signal info to be sent
3906 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3907 siginfo_t __user *, uinfo)
3909 kernel_siginfo_t info;
3910 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3913 return do_rt_sigqueueinfo(pid, sig, &info);
3916 #ifdef CONFIG_COMPAT
3917 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3920 struct compat_siginfo __user *, uinfo)
3922 kernel_siginfo_t info;
3923 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3926 return do_rt_sigqueueinfo(pid, sig, &info);
3930 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
3932 /* This is only valid for single tasks */
3933 if (pid <= 0 || tgid <= 0)
3936 /* Not even root can pretend to send signals from the kernel.
3937 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3939 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3940 (task_pid_vnr(current) != pid))
3943 return do_send_specific(tgid, pid, sig, info);
3946 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3947 siginfo_t __user *, uinfo)
3949 kernel_siginfo_t info;
3950 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3953 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3956 #ifdef CONFIG_COMPAT
3957 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3961 struct compat_siginfo __user *, uinfo)
3963 kernel_siginfo_t info;
3964 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3967 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3972 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3974 void kernel_sigaction(int sig, __sighandler_t action)
3976 spin_lock_irq(¤t->sighand->siglock);
3977 current->sighand->action[sig - 1].sa.sa_handler = action;
3978 if (action == SIG_IGN) {
3982 sigaddset(&mask, sig);
3984 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3985 flush_sigqueue_mask(&mask, ¤t->pending);
3986 recalc_sigpending();
3988 spin_unlock_irq(¤t->sighand->siglock);
3990 EXPORT_SYMBOL(kernel_sigaction);
3992 void __weak sigaction_compat_abi(struct k_sigaction *act,
3993 struct k_sigaction *oact)
3997 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3999 struct task_struct *p = current, *t;
4000 struct k_sigaction *k;
4003 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
4006 k = &p->sighand->action[sig-1];
4008 spin_lock_irq(&p->sighand->siglock);
4013 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
4014 * e.g. by having an architecture use the bit in their uapi.
4016 BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
4019 * Clear unknown flag bits in order to allow userspace to detect missing
4020 * support for flag bits and to allow the kernel to use non-uapi bits
4024 act->sa.sa_flags &= UAPI_SA_FLAGS;
4026 oact->sa.sa_flags &= UAPI_SA_FLAGS;
4028 sigaction_compat_abi(act, oact);
4031 sigdelsetmask(&act->sa.sa_mask,
4032 sigmask(SIGKILL) | sigmask(SIGSTOP));
4036 * "Setting a signal action to SIG_IGN for a signal that is
4037 * pending shall cause the pending signal to be discarded,
4038 * whether or not it is blocked."
4040 * "Setting a signal action to SIG_DFL for a signal that is
4041 * pending and whose default action is to ignore the signal
4042 * (for example, SIGCHLD), shall cause the pending signal to
4043 * be discarded, whether or not it is blocked"
4045 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
4047 sigaddset(&mask, sig);
4048 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
4049 for_each_thread(p, t)
4050 flush_sigqueue_mask(&mask, &t->pending);
4054 spin_unlock_irq(&p->sighand->siglock);
4059 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4062 struct task_struct *t = current;
4065 memset(oss, 0, sizeof(stack_t));
4066 oss->ss_sp = (void __user *) t->sas_ss_sp;
4067 oss->ss_size = t->sas_ss_size;
4068 oss->ss_flags = sas_ss_flags(sp) |
4069 (current->sas_ss_flags & SS_FLAG_BITS);
4073 void __user *ss_sp = ss->ss_sp;
4074 size_t ss_size = ss->ss_size;
4075 unsigned ss_flags = ss->ss_flags;
4078 if (unlikely(on_sig_stack(sp)))
4081 ss_mode = ss_flags & ~SS_FLAG_BITS;
4082 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4086 if (ss_mode == SS_DISABLE) {
4090 if (unlikely(ss_size < min_ss_size))
4094 t->sas_ss_sp = (unsigned long) ss_sp;
4095 t->sas_ss_size = ss_size;
4096 t->sas_ss_flags = ss_flags;
4101 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4105 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4107 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4108 current_user_stack_pointer(),
4110 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4115 int restore_altstack(const stack_t __user *uss)
4118 if (copy_from_user(&new, uss, sizeof(stack_t)))
4120 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4122 /* squash all but EFAULT for now */
4126 int __save_altstack(stack_t __user *uss, unsigned long sp)
4128 struct task_struct *t = current;
4129 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4130 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4131 __put_user(t->sas_ss_size, &uss->ss_size);
4134 if (t->sas_ss_flags & SS_AUTODISARM)
4139 #ifdef CONFIG_COMPAT
4140 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4141 compat_stack_t __user *uoss_ptr)
4147 compat_stack_t uss32;
4148 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4150 uss.ss_sp = compat_ptr(uss32.ss_sp);
4151 uss.ss_flags = uss32.ss_flags;
4152 uss.ss_size = uss32.ss_size;
4154 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4155 compat_user_stack_pointer(),
4156 COMPAT_MINSIGSTKSZ);
4157 if (ret >= 0 && uoss_ptr) {
4159 memset(&old, 0, sizeof(old));
4160 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4161 old.ss_flags = uoss.ss_flags;
4162 old.ss_size = uoss.ss_size;
4163 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4169 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4170 const compat_stack_t __user *, uss_ptr,
4171 compat_stack_t __user *, uoss_ptr)
4173 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4176 int compat_restore_altstack(const compat_stack_t __user *uss)
4178 int err = do_compat_sigaltstack(uss, NULL);
4179 /* squash all but -EFAULT for now */
4180 return err == -EFAULT ? err : 0;
4183 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4186 struct task_struct *t = current;
4187 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4189 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4190 __put_user(t->sas_ss_size, &uss->ss_size);
4193 if (t->sas_ss_flags & SS_AUTODISARM)
4199 #ifdef __ARCH_WANT_SYS_SIGPENDING
4202 * sys_sigpending - examine pending signals
4203 * @uset: where mask of pending signal is returned
4205 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4209 if (sizeof(old_sigset_t) > sizeof(*uset))
4212 do_sigpending(&set);
4214 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4220 #ifdef CONFIG_COMPAT
4221 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4225 do_sigpending(&set);
4227 return put_user(set.sig[0], set32);
4233 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4235 * sys_sigprocmask - examine and change blocked signals
4236 * @how: whether to add, remove, or set signals
4237 * @nset: signals to add or remove (if non-null)
4238 * @oset: previous value of signal mask if non-null
4240 * Some platforms have their own version with special arguments;
4241 * others support only sys_rt_sigprocmask.
4244 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4245 old_sigset_t __user *, oset)
4247 old_sigset_t old_set, new_set;
4248 sigset_t new_blocked;
4250 old_set = current->blocked.sig[0];
4253 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4256 new_blocked = current->blocked;
4260 sigaddsetmask(&new_blocked, new_set);
4263 sigdelsetmask(&new_blocked, new_set);
4266 new_blocked.sig[0] = new_set;
4272 set_current_blocked(&new_blocked);
4276 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4282 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4284 #ifndef CONFIG_ODD_RT_SIGACTION
4286 * sys_rt_sigaction - alter an action taken by a process
4287 * @sig: signal to be sent
4288 * @act: new sigaction
4289 * @oact: used to save the previous sigaction
4290 * @sigsetsize: size of sigset_t type
4292 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4293 const struct sigaction __user *, act,
4294 struct sigaction __user *, oact,
4297 struct k_sigaction new_sa, old_sa;
4300 /* XXX: Don't preclude handling different sized sigset_t's. */
4301 if (sigsetsize != sizeof(sigset_t))
4304 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4307 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4311 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4316 #ifdef CONFIG_COMPAT
4317 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4318 const struct compat_sigaction __user *, act,
4319 struct compat_sigaction __user *, oact,
4320 compat_size_t, sigsetsize)
4322 struct k_sigaction new_ka, old_ka;
4323 #ifdef __ARCH_HAS_SA_RESTORER
4324 compat_uptr_t restorer;
4328 /* XXX: Don't preclude handling different sized sigset_t's. */
4329 if (sigsetsize != sizeof(compat_sigset_t))
4333 compat_uptr_t handler;
4334 ret = get_user(handler, &act->sa_handler);
4335 new_ka.sa.sa_handler = compat_ptr(handler);
4336 #ifdef __ARCH_HAS_SA_RESTORER
4337 ret |= get_user(restorer, &act->sa_restorer);
4338 new_ka.sa.sa_restorer = compat_ptr(restorer);
4340 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4341 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4346 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4348 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4350 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4351 sizeof(oact->sa_mask));
4352 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4353 #ifdef __ARCH_HAS_SA_RESTORER
4354 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4355 &oact->sa_restorer);
4361 #endif /* !CONFIG_ODD_RT_SIGACTION */
4363 #ifdef CONFIG_OLD_SIGACTION
4364 SYSCALL_DEFINE3(sigaction, int, sig,
4365 const struct old_sigaction __user *, act,
4366 struct old_sigaction __user *, oact)
4368 struct k_sigaction new_ka, old_ka;
4373 if (!access_ok(act, sizeof(*act)) ||
4374 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4375 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4376 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4377 __get_user(mask, &act->sa_mask))
4379 #ifdef __ARCH_HAS_KA_RESTORER
4380 new_ka.ka_restorer = NULL;
4382 siginitset(&new_ka.sa.sa_mask, mask);
4385 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4388 if (!access_ok(oact, sizeof(*oact)) ||
4389 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4390 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4391 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4392 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4399 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4400 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4401 const struct compat_old_sigaction __user *, act,
4402 struct compat_old_sigaction __user *, oact)
4404 struct k_sigaction new_ka, old_ka;
4406 compat_old_sigset_t mask;
4407 compat_uptr_t handler, restorer;
4410 if (!access_ok(act, sizeof(*act)) ||
4411 __get_user(handler, &act->sa_handler) ||
4412 __get_user(restorer, &act->sa_restorer) ||
4413 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4414 __get_user(mask, &act->sa_mask))
4417 #ifdef __ARCH_HAS_KA_RESTORER
4418 new_ka.ka_restorer = NULL;
4420 new_ka.sa.sa_handler = compat_ptr(handler);
4421 new_ka.sa.sa_restorer = compat_ptr(restorer);
4422 siginitset(&new_ka.sa.sa_mask, mask);
4425 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4428 if (!access_ok(oact, sizeof(*oact)) ||
4429 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4430 &oact->sa_handler) ||
4431 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4432 &oact->sa_restorer) ||
4433 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4434 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4441 #ifdef CONFIG_SGETMASK_SYSCALL
4444 * For backwards compatibility. Functionality superseded by sigprocmask.
4446 SYSCALL_DEFINE0(sgetmask)
4449 return current->blocked.sig[0];
4452 SYSCALL_DEFINE1(ssetmask, int, newmask)
4454 int old = current->blocked.sig[0];
4457 siginitset(&newset, newmask);
4458 set_current_blocked(&newset);
4462 #endif /* CONFIG_SGETMASK_SYSCALL */
4464 #ifdef __ARCH_WANT_SYS_SIGNAL
4466 * For backwards compatibility. Functionality superseded by sigaction.
4468 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4470 struct k_sigaction new_sa, old_sa;
4473 new_sa.sa.sa_handler = handler;
4474 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4475 sigemptyset(&new_sa.sa.sa_mask);
4477 ret = do_sigaction(sig, &new_sa, &old_sa);
4479 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4481 #endif /* __ARCH_WANT_SYS_SIGNAL */
4483 #ifdef __ARCH_WANT_SYS_PAUSE
4485 SYSCALL_DEFINE0(pause)
4487 while (!signal_pending(current)) {
4488 __set_current_state(TASK_INTERRUPTIBLE);
4491 return -ERESTARTNOHAND;
4496 static int sigsuspend(sigset_t *set)
4498 current->saved_sigmask = current->blocked;
4499 set_current_blocked(set);
4501 while (!signal_pending(current)) {
4502 __set_current_state(TASK_INTERRUPTIBLE);
4505 set_restore_sigmask();
4506 return -ERESTARTNOHAND;
4510 * sys_rt_sigsuspend - replace the signal mask for a value with the
4511 * @unewset value until a signal is received
4512 * @unewset: new signal mask value
4513 * @sigsetsize: size of sigset_t type
4515 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4519 /* XXX: Don't preclude handling different sized sigset_t's. */
4520 if (sigsetsize != sizeof(sigset_t))
4523 if (copy_from_user(&newset, unewset, sizeof(newset)))
4525 return sigsuspend(&newset);
4528 #ifdef CONFIG_COMPAT
4529 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4533 /* XXX: Don't preclude handling different sized sigset_t's. */
4534 if (sigsetsize != sizeof(sigset_t))
4537 if (get_compat_sigset(&newset, unewset))
4539 return sigsuspend(&newset);
4543 #ifdef CONFIG_OLD_SIGSUSPEND
4544 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4547 siginitset(&blocked, mask);
4548 return sigsuspend(&blocked);
4551 #ifdef CONFIG_OLD_SIGSUSPEND3
4552 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4555 siginitset(&blocked, mask);
4556 return sigsuspend(&blocked);
4560 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4565 static inline void siginfo_buildtime_checks(void)
4567 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4569 /* Verify the offsets in the two siginfos match */
4570 #define CHECK_OFFSET(field) \
4571 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4574 CHECK_OFFSET(si_pid);
4575 CHECK_OFFSET(si_uid);
4578 CHECK_OFFSET(si_tid);
4579 CHECK_OFFSET(si_overrun);
4580 CHECK_OFFSET(si_value);
4583 CHECK_OFFSET(si_pid);
4584 CHECK_OFFSET(si_uid);
4585 CHECK_OFFSET(si_value);
4588 CHECK_OFFSET(si_pid);
4589 CHECK_OFFSET(si_uid);
4590 CHECK_OFFSET(si_status);
4591 CHECK_OFFSET(si_utime);
4592 CHECK_OFFSET(si_stime);
4595 CHECK_OFFSET(si_addr);
4596 CHECK_OFFSET(si_addr_lsb);
4597 CHECK_OFFSET(si_lower);
4598 CHECK_OFFSET(si_upper);
4599 CHECK_OFFSET(si_pkey);
4602 CHECK_OFFSET(si_band);
4603 CHECK_OFFSET(si_fd);
4606 CHECK_OFFSET(si_call_addr);
4607 CHECK_OFFSET(si_syscall);
4608 CHECK_OFFSET(si_arch);
4612 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4613 offsetof(struct siginfo, si_addr));
4614 if (sizeof(int) == sizeof(void __user *)) {
4615 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4616 sizeof(void __user *));
4618 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4619 sizeof_field(struct siginfo, si_uid)) !=
4620 sizeof(void __user *));
4621 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4622 offsetof(struct siginfo, si_uid));
4624 #ifdef CONFIG_COMPAT
4625 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4626 offsetof(struct compat_siginfo, si_addr));
4627 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4628 sizeof(compat_uptr_t));
4629 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4630 sizeof_field(struct siginfo, si_pid));
4634 void __init signals_init(void)
4636 siginfo_buildtime_checks();
4638 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
4641 #ifdef CONFIG_KGDB_KDB
4642 #include <linux/kdb.h>
4644 * kdb_send_sig - Allows kdb to send signals without exposing
4645 * signal internals. This function checks if the required locks are
4646 * available before calling the main signal code, to avoid kdb
4649 void kdb_send_sig(struct task_struct *t, int sig)
4651 static struct task_struct *kdb_prev_t;
4653 if (!spin_trylock(&t->sighand->siglock)) {
4654 kdb_printf("Can't do kill command now.\n"
4655 "The sigmask lock is held somewhere else in "
4656 "kernel, try again later\n");
4659 new_t = kdb_prev_t != t;
4661 if (t->state != TASK_RUNNING && new_t) {
4662 spin_unlock(&t->sighand->siglock);
4663 kdb_printf("Process is not RUNNING, sending a signal from "
4664 "kdb risks deadlock\n"
4665 "on the run queue locks. "
4666 "The signal has _not_ been sent.\n"
4667 "Reissue the kill command if you want to risk "
4671 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4672 spin_unlock(&t->sighand->siglock);
4674 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4677 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4679 #endif /* CONFIG_KGDB_KDB */