1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
9 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
10 * Changes to use preallocated sigqueue structures
11 * to allow signals to be sent reliably.
14 #include <linux/slab.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/debug.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/sched/cputime.h>
23 #include <linux/file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/tty.h>
27 #include <linux/binfmts.h>
28 #include <linux/coredump.h>
29 #include <linux/security.h>
30 #include <linux/syscalls.h>
31 #include <linux/ptrace.h>
32 #include <linux/signal.h>
33 #include <linux/signalfd.h>
34 #include <linux/ratelimit.h>
35 #include <linux/tracehook.h>
36 #include <linux/capability.h>
37 #include <linux/freezer.h>
38 #include <linux/pid_namespace.h>
39 #include <linux/nsproxy.h>
40 #include <linux/user_namespace.h>
41 #include <linux/uprobes.h>
42 #include <linux/compat.h>
43 #include <linux/cn_proc.h>
44 #include <linux/compiler.h>
45 #include <linux/posix-timers.h>
46 #include <linux/cgroup.h>
47 #include <linux/audit.h>
49 #define CREATE_TRACE_POINTS
50 #include <trace/events/signal.h>
52 #include <asm/param.h>
53 #include <linux/uaccess.h>
54 #include <asm/unistd.h>
55 #include <asm/siginfo.h>
56 #include <asm/cacheflush.h>
57 #include <asm/syscall.h> /* for syscall_get_* */
60 * SLAB caches for signal bits.
63 static struct kmem_cache *sigqueue_cachep;
65 int print_fatal_signals __read_mostly;
67 static void __user *sig_handler(struct task_struct *t, int sig)
69 return t->sighand->action[sig - 1].sa.sa_handler;
72 static inline bool sig_handler_ignored(void __user *handler, int sig)
74 /* Is it explicitly or implicitly ignored? */
75 return handler == SIG_IGN ||
76 (handler == SIG_DFL && sig_kernel_ignore(sig));
79 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
83 handler = sig_handler(t, sig);
85 /* SIGKILL and SIGSTOP may not be sent to the global init */
86 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
89 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
90 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
93 /* Only allow kernel generated signals to this kthread */
94 if (unlikely((t->flags & PF_KTHREAD) &&
95 (handler == SIG_KTHREAD_KERNEL) && !force))
98 return sig_handler_ignored(handler, sig);
101 static bool sig_ignored(struct task_struct *t, int sig, bool force)
104 * Blocked signals are never ignored, since the
105 * signal handler may change by the time it is
108 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
112 * Tracers may want to know about even ignored signal unless it
113 * is SIGKILL which can't be reported anyway but can be ignored
114 * by SIGNAL_UNKILLABLE task.
116 if (t->ptrace && sig != SIGKILL)
119 return sig_task_ignored(t, sig, force);
123 * Re-calculate pending state from the set of locally pending
124 * signals, globally pending signals, and blocked signals.
126 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
131 switch (_NSIG_WORDS) {
133 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
134 ready |= signal->sig[i] &~ blocked->sig[i];
137 case 4: ready = signal->sig[3] &~ blocked->sig[3];
138 ready |= signal->sig[2] &~ blocked->sig[2];
139 ready |= signal->sig[1] &~ blocked->sig[1];
140 ready |= signal->sig[0] &~ blocked->sig[0];
143 case 2: ready = signal->sig[1] &~ blocked->sig[1];
144 ready |= signal->sig[0] &~ blocked->sig[0];
147 case 1: ready = signal->sig[0] &~ blocked->sig[0];
152 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
154 static bool recalc_sigpending_tsk(struct task_struct *t)
156 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
157 PENDING(&t->pending, &t->blocked) ||
158 PENDING(&t->signal->shared_pending, &t->blocked) ||
159 cgroup_task_frozen(t)) {
160 set_tsk_thread_flag(t, TIF_SIGPENDING);
165 * We must never clear the flag in another thread, or in current
166 * when it's possible the current syscall is returning -ERESTART*.
167 * So we don't clear it here, and only callers who know they should do.
173 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
174 * This is superfluous when called on current, the wakeup is a harmless no-op.
176 void recalc_sigpending_and_wake(struct task_struct *t)
178 if (recalc_sigpending_tsk(t))
179 signal_wake_up(t, 0);
182 void recalc_sigpending(void)
184 if (!recalc_sigpending_tsk(current) && !freezing(current))
185 clear_thread_flag(TIF_SIGPENDING);
188 EXPORT_SYMBOL(recalc_sigpending);
190 void calculate_sigpending(void)
192 /* Have any signals or users of TIF_SIGPENDING been delayed
195 spin_lock_irq(¤t->sighand->siglock);
196 set_tsk_thread_flag(current, TIF_SIGPENDING);
198 spin_unlock_irq(¤t->sighand->siglock);
201 /* Given the mask, find the first available signal that should be serviced. */
203 #define SYNCHRONOUS_MASK \
204 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
205 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
207 int next_signal(struct sigpending *pending, sigset_t *mask)
209 unsigned long i, *s, *m, x;
212 s = pending->signal.sig;
216 * Handle the first word specially: it contains the
217 * synchronous signals that need to be dequeued first.
221 if (x & SYNCHRONOUS_MASK)
222 x &= SYNCHRONOUS_MASK;
227 switch (_NSIG_WORDS) {
229 for (i = 1; i < _NSIG_WORDS; ++i) {
233 sig = ffz(~x) + i*_NSIG_BPW + 1;
242 sig = ffz(~x) + _NSIG_BPW + 1;
253 static inline void print_dropped_signal(int sig)
255 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
257 if (!print_fatal_signals)
260 if (!__ratelimit(&ratelimit_state))
263 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
264 current->comm, current->pid, sig);
268 * task_set_jobctl_pending - set jobctl pending bits
270 * @mask: pending bits to set
272 * Clear @mask from @task->jobctl. @mask must be subset of
273 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
274 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
275 * cleared. If @task is already being killed or exiting, this function
279 * Must be called with @task->sighand->siglock held.
282 * %true if @mask is set, %false if made noop because @task was dying.
284 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
286 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
287 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
288 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
290 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
293 if (mask & JOBCTL_STOP_SIGMASK)
294 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
296 task->jobctl |= mask;
301 * task_clear_jobctl_trapping - clear jobctl trapping bit
304 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
305 * Clear it and wake up the ptracer. Note that we don't need any further
306 * locking. @task->siglock guarantees that @task->parent points to the
310 * Must be called with @task->sighand->siglock held.
312 void task_clear_jobctl_trapping(struct task_struct *task)
314 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
315 task->jobctl &= ~JOBCTL_TRAPPING;
316 smp_mb(); /* advised by wake_up_bit() */
317 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
322 * task_clear_jobctl_pending - clear jobctl pending bits
324 * @mask: pending bits to clear
326 * Clear @mask from @task->jobctl. @mask must be subset of
327 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
328 * STOP bits are cleared together.
330 * If clearing of @mask leaves no stop or trap pending, this function calls
331 * task_clear_jobctl_trapping().
334 * Must be called with @task->sighand->siglock held.
336 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
338 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
340 if (mask & JOBCTL_STOP_PENDING)
341 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
343 task->jobctl &= ~mask;
345 if (!(task->jobctl & JOBCTL_PENDING_MASK))
346 task_clear_jobctl_trapping(task);
350 * task_participate_group_stop - participate in a group stop
351 * @task: task participating in a group stop
353 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
354 * Group stop states are cleared and the group stop count is consumed if
355 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
356 * stop, the appropriate `SIGNAL_*` flags are set.
359 * Must be called with @task->sighand->siglock held.
362 * %true if group stop completion should be notified to the parent, %false
365 static bool task_participate_group_stop(struct task_struct *task)
367 struct signal_struct *sig = task->signal;
368 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
370 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
372 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
377 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
378 sig->group_stop_count--;
381 * Tell the caller to notify completion iff we are entering into a
382 * fresh group stop. Read comment in do_signal_stop() for details.
384 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
385 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
391 void task_join_group_stop(struct task_struct *task)
393 unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
394 struct signal_struct *sig = current->signal;
396 if (sig->group_stop_count) {
397 sig->group_stop_count++;
398 mask |= JOBCTL_STOP_CONSUME;
399 } else if (!(sig->flags & SIGNAL_STOP_STOPPED))
402 /* Have the new thread join an on-going signal group stop */
403 task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
407 * allocate a new signal queue record
408 * - this may be called without locks if and only if t == current, otherwise an
409 * appropriate lock must be held to stop the target task from exiting
411 static struct sigqueue *
412 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
413 int override_rlimit, const unsigned int sigqueue_flags)
415 struct sigqueue *q = NULL;
416 struct ucounts *ucounts = NULL;
420 * Protect access to @t credentials. This can go away when all
421 * callers hold rcu read lock.
423 * NOTE! A pending signal will hold on to the user refcount,
424 * and we get/put the refcount only when the sigpending count
425 * changes from/to zero.
428 ucounts = task_ucounts(t);
429 sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
434 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
435 q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
437 print_dropped_signal(sig);
440 if (unlikely(q == NULL)) {
441 dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
443 INIT_LIST_HEAD(&q->list);
444 q->flags = sigqueue_flags;
445 q->ucounts = ucounts;
450 static void __sigqueue_free(struct sigqueue *q)
452 if (q->flags & SIGQUEUE_PREALLOC)
455 dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING);
458 kmem_cache_free(sigqueue_cachep, q);
461 void flush_sigqueue(struct sigpending *queue)
465 sigemptyset(&queue->signal);
466 while (!list_empty(&queue->list)) {
467 q = list_entry(queue->list.next, struct sigqueue , list);
468 list_del_init(&q->list);
474 * Flush all pending signals for this kthread.
476 void flush_signals(struct task_struct *t)
480 spin_lock_irqsave(&t->sighand->siglock, flags);
481 clear_tsk_thread_flag(t, TIF_SIGPENDING);
482 flush_sigqueue(&t->pending);
483 flush_sigqueue(&t->signal->shared_pending);
484 spin_unlock_irqrestore(&t->sighand->siglock, flags);
486 EXPORT_SYMBOL(flush_signals);
488 #ifdef CONFIG_POSIX_TIMERS
489 static void __flush_itimer_signals(struct sigpending *pending)
491 sigset_t signal, retain;
492 struct sigqueue *q, *n;
494 signal = pending->signal;
495 sigemptyset(&retain);
497 list_for_each_entry_safe(q, n, &pending->list, list) {
498 int sig = q->info.si_signo;
500 if (likely(q->info.si_code != SI_TIMER)) {
501 sigaddset(&retain, sig);
503 sigdelset(&signal, sig);
504 list_del_init(&q->list);
509 sigorsets(&pending->signal, &signal, &retain);
512 void flush_itimer_signals(void)
514 struct task_struct *tsk = current;
517 spin_lock_irqsave(&tsk->sighand->siglock, flags);
518 __flush_itimer_signals(&tsk->pending);
519 __flush_itimer_signals(&tsk->signal->shared_pending);
520 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
524 void ignore_signals(struct task_struct *t)
528 for (i = 0; i < _NSIG; ++i)
529 t->sighand->action[i].sa.sa_handler = SIG_IGN;
535 * Flush all handlers for a task.
539 flush_signal_handlers(struct task_struct *t, int force_default)
542 struct k_sigaction *ka = &t->sighand->action[0];
543 for (i = _NSIG ; i != 0 ; i--) {
544 if (force_default || ka->sa.sa_handler != SIG_IGN)
545 ka->sa.sa_handler = SIG_DFL;
547 #ifdef __ARCH_HAS_SA_RESTORER
548 ka->sa.sa_restorer = NULL;
550 sigemptyset(&ka->sa.sa_mask);
555 bool unhandled_signal(struct task_struct *tsk, int sig)
557 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
558 if (is_global_init(tsk))
561 if (handler != SIG_IGN && handler != SIG_DFL)
564 /* if ptraced, let the tracer determine */
568 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
571 struct sigqueue *q, *first = NULL;
574 * Collect the siginfo appropriate to this signal. Check if
575 * there is another siginfo for the same signal.
577 list_for_each_entry(q, &list->list, list) {
578 if (q->info.si_signo == sig) {
585 sigdelset(&list->signal, sig);
589 list_del_init(&first->list);
590 copy_siginfo(info, &first->info);
593 (first->flags & SIGQUEUE_PREALLOC) &&
594 (info->si_code == SI_TIMER) &&
595 (info->si_sys_private);
597 __sigqueue_free(first);
600 * Ok, it wasn't in the queue. This must be
601 * a fast-pathed signal or we must have been
602 * out of queue space. So zero out the info.
605 info->si_signo = sig;
607 info->si_code = SI_USER;
613 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
614 kernel_siginfo_t *info, bool *resched_timer)
616 int sig = next_signal(pending, mask);
619 collect_signal(sig, pending, info, resched_timer);
624 * Dequeue a signal and return the element to the caller, which is
625 * expected to free it.
627 * All callers have to hold the siglock.
629 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
631 bool resched_timer = false;
634 /* We only dequeue private signals from ourselves, we don't let
635 * signalfd steal them
637 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
639 signr = __dequeue_signal(&tsk->signal->shared_pending,
640 mask, info, &resched_timer);
641 #ifdef CONFIG_POSIX_TIMERS
645 * itimers are process shared and we restart periodic
646 * itimers in the signal delivery path to prevent DoS
647 * attacks in the high resolution timer case. This is
648 * compliant with the old way of self-restarting
649 * itimers, as the SIGALRM is a legacy signal and only
650 * queued once. Changing the restart behaviour to
651 * restart the timer in the signal dequeue path is
652 * reducing the timer noise on heavy loaded !highres
655 if (unlikely(signr == SIGALRM)) {
656 struct hrtimer *tmr = &tsk->signal->real_timer;
658 if (!hrtimer_is_queued(tmr) &&
659 tsk->signal->it_real_incr != 0) {
660 hrtimer_forward(tmr, tmr->base->get_time(),
661 tsk->signal->it_real_incr);
662 hrtimer_restart(tmr);
672 if (unlikely(sig_kernel_stop(signr))) {
674 * Set a marker that we have dequeued a stop signal. Our
675 * caller might release the siglock and then the pending
676 * stop signal it is about to process is no longer in the
677 * pending bitmasks, but must still be cleared by a SIGCONT
678 * (and overruled by a SIGKILL). So those cases clear this
679 * shared flag after we've set it. Note that this flag may
680 * remain set after the signal we return is ignored or
681 * handled. That doesn't matter because its only purpose
682 * is to alert stop-signal processing code when another
683 * processor has come along and cleared the flag.
685 current->jobctl |= JOBCTL_STOP_DEQUEUED;
687 #ifdef CONFIG_POSIX_TIMERS
690 * Release the siglock to ensure proper locking order
691 * of timer locks outside of siglocks. Note, we leave
692 * irqs disabled here, since the posix-timers code is
693 * about to disable them again anyway.
695 spin_unlock(&tsk->sighand->siglock);
696 posixtimer_rearm(info);
697 spin_lock(&tsk->sighand->siglock);
699 /* Don't expose the si_sys_private value to userspace */
700 info->si_sys_private = 0;
705 EXPORT_SYMBOL_GPL(dequeue_signal);
707 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
709 struct task_struct *tsk = current;
710 struct sigpending *pending = &tsk->pending;
711 struct sigqueue *q, *sync = NULL;
714 * Might a synchronous signal be in the queue?
716 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
720 * Return the first synchronous signal in the queue.
722 list_for_each_entry(q, &pending->list, list) {
723 /* Synchronous signals have a positive si_code */
724 if ((q->info.si_code > SI_USER) &&
725 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
733 * Check if there is another siginfo for the same signal.
735 list_for_each_entry_continue(q, &pending->list, list) {
736 if (q->info.si_signo == sync->info.si_signo)
740 sigdelset(&pending->signal, sync->info.si_signo);
743 list_del_init(&sync->list);
744 copy_siginfo(info, &sync->info);
745 __sigqueue_free(sync);
746 return info->si_signo;
750 * Tell a process that it has a new active signal..
752 * NOTE! we rely on the previous spin_lock to
753 * lock interrupts for us! We can only be called with
754 * "siglock" held, and the local interrupt must
755 * have been disabled when that got acquired!
757 * No need to set need_resched since signal event passing
758 * goes through ->blocked
760 void signal_wake_up_state(struct task_struct *t, unsigned int state)
762 set_tsk_thread_flag(t, TIF_SIGPENDING);
764 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
765 * case. We don't check t->state here because there is a race with it
766 * executing another processor and just now entering stopped state.
767 * By using wake_up_state, we ensure the process will wake up and
768 * handle its death signal.
770 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
775 * Remove signals in mask from the pending set and queue.
776 * Returns 1 if any signals were found.
778 * All callers must be holding the siglock.
780 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
782 struct sigqueue *q, *n;
785 sigandsets(&m, mask, &s->signal);
786 if (sigisemptyset(&m))
789 sigandnsets(&s->signal, &s->signal, mask);
790 list_for_each_entry_safe(q, n, &s->list, list) {
791 if (sigismember(mask, q->info.si_signo)) {
792 list_del_init(&q->list);
798 static inline int is_si_special(const struct kernel_siginfo *info)
800 return info <= SEND_SIG_PRIV;
803 static inline bool si_fromuser(const struct kernel_siginfo *info)
805 return info == SEND_SIG_NOINFO ||
806 (!is_si_special(info) && SI_FROMUSER(info));
810 * called with RCU read lock from check_kill_permission()
812 static bool kill_ok_by_cred(struct task_struct *t)
814 const struct cred *cred = current_cred();
815 const struct cred *tcred = __task_cred(t);
817 return uid_eq(cred->euid, tcred->suid) ||
818 uid_eq(cred->euid, tcred->uid) ||
819 uid_eq(cred->uid, tcred->suid) ||
820 uid_eq(cred->uid, tcred->uid) ||
821 ns_capable(tcred->user_ns, CAP_KILL);
825 * Bad permissions for sending the signal
826 * - the caller must hold the RCU read lock
828 static int check_kill_permission(int sig, struct kernel_siginfo *info,
829 struct task_struct *t)
834 if (!valid_signal(sig))
837 if (!si_fromuser(info))
840 error = audit_signal_info(sig, t); /* Let audit system see the signal */
844 if (!same_thread_group(current, t) &&
845 !kill_ok_by_cred(t)) {
848 sid = task_session(t);
850 * We don't return the error if sid == NULL. The
851 * task was unhashed, the caller must notice this.
853 if (!sid || sid == task_session(current))
861 return security_task_kill(t, info, sig, NULL);
865 * ptrace_trap_notify - schedule trap to notify ptracer
866 * @t: tracee wanting to notify tracer
868 * This function schedules sticky ptrace trap which is cleared on the next
869 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
872 * If @t is running, STOP trap will be taken. If trapped for STOP and
873 * ptracer is listening for events, tracee is woken up so that it can
874 * re-trap for the new event. If trapped otherwise, STOP trap will be
875 * eventually taken without returning to userland after the existing traps
876 * are finished by PTRACE_CONT.
879 * Must be called with @task->sighand->siglock held.
881 static void ptrace_trap_notify(struct task_struct *t)
883 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
884 assert_spin_locked(&t->sighand->siglock);
886 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
887 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
891 * Handle magic process-wide effects of stop/continue signals. Unlike
892 * the signal actions, these happen immediately at signal-generation
893 * time regardless of blocking, ignoring, or handling. This does the
894 * actual continuing for SIGCONT, but not the actual stopping for stop
895 * signals. The process stop is done as a signal action for SIG_DFL.
897 * Returns true if the signal should be actually delivered, otherwise
898 * it should be dropped.
900 static bool prepare_signal(int sig, struct task_struct *p, bool force)
902 struct signal_struct *signal = p->signal;
903 struct task_struct *t;
906 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
907 if (!(signal->flags & SIGNAL_GROUP_EXIT))
908 return sig == SIGKILL;
910 * The process is in the middle of dying, nothing to do.
912 } else if (sig_kernel_stop(sig)) {
914 * This is a stop signal. Remove SIGCONT from all queues.
916 siginitset(&flush, sigmask(SIGCONT));
917 flush_sigqueue_mask(&flush, &signal->shared_pending);
918 for_each_thread(p, t)
919 flush_sigqueue_mask(&flush, &t->pending);
920 } else if (sig == SIGCONT) {
923 * Remove all stop signals from all queues, wake all threads.
925 siginitset(&flush, SIG_KERNEL_STOP_MASK);
926 flush_sigqueue_mask(&flush, &signal->shared_pending);
927 for_each_thread(p, t) {
928 flush_sigqueue_mask(&flush, &t->pending);
929 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
930 if (likely(!(t->ptrace & PT_SEIZED)))
931 wake_up_state(t, __TASK_STOPPED);
933 ptrace_trap_notify(t);
937 * Notify the parent with CLD_CONTINUED if we were stopped.
939 * If we were in the middle of a group stop, we pretend it
940 * was already finished, and then continued. Since SIGCHLD
941 * doesn't queue we report only CLD_STOPPED, as if the next
942 * CLD_CONTINUED was dropped.
945 if (signal->flags & SIGNAL_STOP_STOPPED)
946 why |= SIGNAL_CLD_CONTINUED;
947 else if (signal->group_stop_count)
948 why |= SIGNAL_CLD_STOPPED;
952 * The first thread which returns from do_signal_stop()
953 * will take ->siglock, notice SIGNAL_CLD_MASK, and
954 * notify its parent. See get_signal().
956 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
957 signal->group_stop_count = 0;
958 signal->group_exit_code = 0;
962 return !sig_ignored(p, sig, force);
966 * Test if P wants to take SIG. After we've checked all threads with this,
967 * it's equivalent to finding no threads not blocking SIG. Any threads not
968 * blocking SIG were ruled out because they are not running and already
969 * have pending signals. Such threads will dequeue from the shared queue
970 * as soon as they're available, so putting the signal on the shared queue
971 * will be equivalent to sending it to one such thread.
973 static inline bool wants_signal(int sig, struct task_struct *p)
975 if (sigismember(&p->blocked, sig))
978 if (p->flags & PF_EXITING)
984 if (task_is_stopped_or_traced(p))
987 return task_curr(p) || !task_sigpending(p);
990 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
992 struct signal_struct *signal = p->signal;
993 struct task_struct *t;
996 * Now find a thread we can wake up to take the signal off the queue.
998 * If the main thread wants the signal, it gets first crack.
999 * Probably the least surprising to the average bear.
1001 if (wants_signal(sig, p))
1003 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1005 * There is just one thread and it does not need to be woken.
1006 * It will dequeue unblocked signals before it runs again.
1011 * Otherwise try to find a suitable thread.
1013 t = signal->curr_target;
1014 while (!wants_signal(sig, t)) {
1016 if (t == signal->curr_target)
1018 * No thread needs to be woken.
1019 * Any eligible threads will see
1020 * the signal in the queue soon.
1024 signal->curr_target = t;
1028 * Found a killable thread. If the signal will be fatal,
1029 * then start taking the whole group down immediately.
1031 if (sig_fatal(p, sig) &&
1032 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1033 !sigismember(&t->real_blocked, sig) &&
1034 (sig == SIGKILL || !p->ptrace)) {
1036 * This signal will be fatal to the whole group.
1038 if (!sig_kernel_coredump(sig)) {
1040 * Start a group exit and wake everybody up.
1041 * This way we don't have other threads
1042 * running and doing things after a slower
1043 * thread has the fatal signal pending.
1045 signal->flags = SIGNAL_GROUP_EXIT;
1046 signal->group_exit_code = sig;
1047 signal->group_stop_count = 0;
1050 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1051 sigaddset(&t->pending.signal, SIGKILL);
1052 signal_wake_up(t, 1);
1053 } while_each_thread(p, t);
1059 * The signal is already in the shared-pending queue.
1060 * Tell the chosen thread to wake up and dequeue it.
1062 signal_wake_up(t, sig == SIGKILL);
1066 static inline bool legacy_queue(struct sigpending *signals, int sig)
1068 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1071 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1072 enum pid_type type, bool force)
1074 struct sigpending *pending;
1076 int override_rlimit;
1077 int ret = 0, result;
1079 assert_spin_locked(&t->sighand->siglock);
1081 result = TRACE_SIGNAL_IGNORED;
1082 if (!prepare_signal(sig, t, force))
1085 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1087 * Short-circuit ignored signals and support queuing
1088 * exactly one non-rt signal, so that we can get more
1089 * detailed information about the cause of the signal.
1091 result = TRACE_SIGNAL_ALREADY_PENDING;
1092 if (legacy_queue(pending, sig))
1095 result = TRACE_SIGNAL_DELIVERED;
1097 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1099 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1103 * Real-time signals must be queued if sent by sigqueue, or
1104 * some other real-time mechanism. It is implementation
1105 * defined whether kill() does so. We attempt to do so, on
1106 * the principle of least surprise, but since kill is not
1107 * allowed to fail with EAGAIN when low on memory we just
1108 * make sure at least one signal gets delivered and don't
1109 * pass on the info struct.
1112 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1114 override_rlimit = 0;
1116 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
1119 list_add_tail(&q->list, &pending->list);
1120 switch ((unsigned long) info) {
1121 case (unsigned long) SEND_SIG_NOINFO:
1122 clear_siginfo(&q->info);
1123 q->info.si_signo = sig;
1124 q->info.si_errno = 0;
1125 q->info.si_code = SI_USER;
1126 q->info.si_pid = task_tgid_nr_ns(current,
1127 task_active_pid_ns(t));
1130 from_kuid_munged(task_cred_xxx(t, user_ns),
1134 case (unsigned long) SEND_SIG_PRIV:
1135 clear_siginfo(&q->info);
1136 q->info.si_signo = sig;
1137 q->info.si_errno = 0;
1138 q->info.si_code = SI_KERNEL;
1143 copy_siginfo(&q->info, info);
1146 } else if (!is_si_special(info) &&
1147 sig >= SIGRTMIN && info->si_code != SI_USER) {
1149 * Queue overflow, abort. We may abort if the
1150 * signal was rt and sent by user using something
1151 * other than kill().
1153 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1158 * This is a silent loss of information. We still
1159 * send the signal, but the *info bits are lost.
1161 result = TRACE_SIGNAL_LOSE_INFO;
1165 signalfd_notify(t, sig);
1166 sigaddset(&pending->signal, sig);
1168 /* Let multiprocess signals appear after on-going forks */
1169 if (type > PIDTYPE_TGID) {
1170 struct multiprocess_signals *delayed;
1171 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1172 sigset_t *signal = &delayed->signal;
1173 /* Can't queue both a stop and a continue signal */
1175 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1176 else if (sig_kernel_stop(sig))
1177 sigdelset(signal, SIGCONT);
1178 sigaddset(signal, sig);
1182 complete_signal(sig, t, type);
1184 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1188 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1191 switch (siginfo_layout(info->si_signo, info->si_code)) {
1200 case SIL_FAULT_TRAPNO:
1201 case SIL_FAULT_MCEERR:
1202 case SIL_FAULT_BNDERR:
1203 case SIL_FAULT_PKUERR:
1204 case SIL_FAULT_PERF_EVENT:
1212 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1215 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1218 if (info == SEND_SIG_NOINFO) {
1219 /* Force if sent from an ancestor pid namespace */
1220 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1221 } else if (info == SEND_SIG_PRIV) {
1222 /* Don't ignore kernel generated signals */
1224 } else if (has_si_pid_and_uid(info)) {
1225 /* SIGKILL and SIGSTOP is special or has ids */
1226 struct user_namespace *t_user_ns;
1229 t_user_ns = task_cred_xxx(t, user_ns);
1230 if (current_user_ns() != t_user_ns) {
1231 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1232 info->si_uid = from_kuid_munged(t_user_ns, uid);
1236 /* A kernel generated signal? */
1237 force = (info->si_code == SI_KERNEL);
1239 /* From an ancestor pid namespace? */
1240 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1245 return __send_signal(sig, info, t, type, force);
1248 static void print_fatal_signal(int signr)
1250 struct pt_regs *regs = signal_pt_regs();
1251 pr_info("potentially unexpected fatal signal %d.\n", signr);
1253 #if defined(__i386__) && !defined(__arch_um__)
1254 pr_info("code at %08lx: ", regs->ip);
1257 for (i = 0; i < 16; i++) {
1260 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1262 pr_cont("%02x ", insn);
1272 static int __init setup_print_fatal_signals(char *str)
1274 get_option (&str, &print_fatal_signals);
1279 __setup("print-fatal-signals=", setup_print_fatal_signals);
1282 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1284 return send_signal(sig, info, p, PIDTYPE_TGID);
1287 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1290 unsigned long flags;
1293 if (lock_task_sighand(p, &flags)) {
1294 ret = send_signal(sig, info, p, type);
1295 unlock_task_sighand(p, &flags);
1302 HANDLER_CURRENT, /* If reachable use the current handler */
1303 HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */
1304 HANDLER_EXIT, /* Only visible as the process exit code */
1308 * Force a signal that the process can't ignore: if necessary
1309 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1311 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1312 * since we do not want to have a signal handler that was blocked
1313 * be invoked when user space had explicitly blocked it.
1315 * We don't want to have recursive SIGSEGV's etc, for example,
1316 * that is why we also clear SIGNAL_UNKILLABLE.
1319 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
1320 enum sig_handler handler)
1322 unsigned long int flags;
1323 int ret, blocked, ignored;
1324 struct k_sigaction *action;
1325 int sig = info->si_signo;
1328 * On some archs, PREEMPT_RT has to delay sending a signal from a trap
1329 * since it can not enable preemption, and the signal code's spin_locks
1330 * turn into mutexes. Instead, it must set TIF_NOTIFY_RESUME which will
1331 * send the signal on exit of the trap.
1333 #ifdef ARCH_RT_DELAYS_SIGNAL_SEND
1335 struct task_struct *t = current;
1337 if (WARN_ON_ONCE(t->forced_info.si_signo))
1340 if (is_si_special(info)) {
1341 WARN_ON_ONCE(info != SEND_SIG_PRIV);
1342 t->forced_info.si_signo = info->si_signo;
1343 t->forced_info.si_errno = 0;
1344 t->forced_info.si_code = SI_KERNEL;
1345 t->forced_info.si_pid = 0;
1346 t->forced_info.si_uid = 0;
1348 t->forced_info = *info;
1351 set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
1355 spin_lock_irqsave(&t->sighand->siglock, flags);
1356 action = &t->sighand->action[sig-1];
1357 ignored = action->sa.sa_handler == SIG_IGN;
1358 blocked = sigismember(&t->blocked, sig);
1359 if (blocked || ignored || (handler != HANDLER_CURRENT)) {
1360 action->sa.sa_handler = SIG_DFL;
1361 if (handler == HANDLER_EXIT)
1362 action->sa.sa_flags |= SA_IMMUTABLE;
1364 sigdelset(&t->blocked, sig);
1365 recalc_sigpending_and_wake(t);
1369 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1370 * debugging to leave init killable. But HANDLER_EXIT is always fatal.
1372 if (action->sa.sa_handler == SIG_DFL &&
1373 (!t->ptrace || (handler == HANDLER_EXIT)))
1374 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1375 ret = send_signal(sig, info, t, PIDTYPE_PID);
1376 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1381 int force_sig_info(struct kernel_siginfo *info)
1383 return force_sig_info_to_task(info, current, HANDLER_CURRENT);
1387 * Nuke all other threads in the group.
1389 int zap_other_threads(struct task_struct *p)
1391 struct task_struct *t = p;
1394 p->signal->group_stop_count = 0;
1396 while_each_thread(p, t) {
1397 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1400 /* Don't bother with already dead threads */
1403 sigaddset(&t->pending.signal, SIGKILL);
1404 signal_wake_up(t, 1);
1410 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1411 unsigned long *flags)
1413 struct sighand_struct *sighand;
1417 sighand = rcu_dereference(tsk->sighand);
1418 if (unlikely(sighand == NULL))
1422 * This sighand can be already freed and even reused, but
1423 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1424 * initializes ->siglock: this slab can't go away, it has
1425 * the same object type, ->siglock can't be reinitialized.
1427 * We need to ensure that tsk->sighand is still the same
1428 * after we take the lock, we can race with de_thread() or
1429 * __exit_signal(). In the latter case the next iteration
1430 * must see ->sighand == NULL.
1432 spin_lock_irqsave(&sighand->siglock, *flags);
1433 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1435 spin_unlock_irqrestore(&sighand->siglock, *flags);
1442 #ifdef CONFIG_LOCKDEP
1443 void lockdep_assert_task_sighand_held(struct task_struct *task)
1445 struct sighand_struct *sighand;
1448 sighand = rcu_dereference(task->sighand);
1450 lockdep_assert_held(&sighand->siglock);
1458 * send signal info to all the members of a group
1460 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1461 struct task_struct *p, enum pid_type type)
1466 ret = check_kill_permission(sig, info, p);
1470 ret = do_send_sig_info(sig, info, p, type);
1476 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1477 * control characters do (^C, ^Z etc)
1478 * - the caller must hold at least a readlock on tasklist_lock
1480 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1482 struct task_struct *p = NULL;
1483 int retval, success;
1487 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1488 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1491 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1492 return success ? 0 : retval;
1495 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1498 struct task_struct *p;
1502 p = pid_task(pid, PIDTYPE_PID);
1504 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1506 if (likely(!p || error != -ESRCH))
1510 * The task was unhashed in between, try again. If it
1511 * is dead, pid_task() will return NULL, if we race with
1512 * de_thread() it will find the new leader.
1517 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1521 error = kill_pid_info(sig, info, find_vpid(pid));
1526 static inline bool kill_as_cred_perm(const struct cred *cred,
1527 struct task_struct *target)
1529 const struct cred *pcred = __task_cred(target);
1531 return uid_eq(cred->euid, pcred->suid) ||
1532 uid_eq(cred->euid, pcred->uid) ||
1533 uid_eq(cred->uid, pcred->suid) ||
1534 uid_eq(cred->uid, pcred->uid);
1538 * The usb asyncio usage of siginfo is wrong. The glibc support
1539 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1540 * AKA after the generic fields:
1541 * kernel_pid_t si_pid;
1542 * kernel_uid32_t si_uid;
1543 * sigval_t si_value;
1545 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1546 * after the generic fields is:
1547 * void __user *si_addr;
1549 * This is a practical problem when there is a 64bit big endian kernel
1550 * and a 32bit userspace. As the 32bit address will encoded in the low
1551 * 32bits of the pointer. Those low 32bits will be stored at higher
1552 * address than appear in a 32 bit pointer. So userspace will not
1553 * see the address it was expecting for it's completions.
1555 * There is nothing in the encoding that can allow
1556 * copy_siginfo_to_user32 to detect this confusion of formats, so
1557 * handle this by requiring the caller of kill_pid_usb_asyncio to
1558 * notice when this situration takes place and to store the 32bit
1559 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1562 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1563 struct pid *pid, const struct cred *cred)
1565 struct kernel_siginfo info;
1566 struct task_struct *p;
1567 unsigned long flags;
1570 if (!valid_signal(sig))
1573 clear_siginfo(&info);
1574 info.si_signo = sig;
1575 info.si_errno = errno;
1576 info.si_code = SI_ASYNCIO;
1577 *((sigval_t *)&info.si_pid) = addr;
1580 p = pid_task(pid, PIDTYPE_PID);
1585 if (!kill_as_cred_perm(cred, p)) {
1589 ret = security_task_kill(p, &info, sig, cred);
1594 if (lock_task_sighand(p, &flags)) {
1595 ret = __send_signal(sig, &info, p, PIDTYPE_TGID, false);
1596 unlock_task_sighand(p, &flags);
1604 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1607 * kill_something_info() interprets pid in interesting ways just like kill(2).
1609 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1610 * is probably wrong. Should make it like BSD or SYSV.
1613 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1618 return kill_proc_info(sig, info, pid);
1620 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1624 read_lock(&tasklist_lock);
1626 ret = __kill_pgrp_info(sig, info,
1627 pid ? find_vpid(-pid) : task_pgrp(current));
1629 int retval = 0, count = 0;
1630 struct task_struct * p;
1632 for_each_process(p) {
1633 if (task_pid_vnr(p) > 1 &&
1634 !same_thread_group(p, current)) {
1635 int err = group_send_sig_info(sig, info, p,
1642 ret = count ? retval : -ESRCH;
1644 read_unlock(&tasklist_lock);
1650 * These are for backward compatibility with the rest of the kernel source.
1653 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1656 * Make sure legacy kernel users don't send in bad values
1657 * (normal paths check this in check_kill_permission).
1659 if (!valid_signal(sig))
1662 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1664 EXPORT_SYMBOL(send_sig_info);
1666 #define __si_special(priv) \
1667 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1670 send_sig(int sig, struct task_struct *p, int priv)
1672 return send_sig_info(sig, __si_special(priv), p);
1674 EXPORT_SYMBOL(send_sig);
1676 void force_sig(int sig)
1678 struct kernel_siginfo info;
1680 clear_siginfo(&info);
1681 info.si_signo = sig;
1683 info.si_code = SI_KERNEL;
1686 force_sig_info(&info);
1688 EXPORT_SYMBOL(force_sig);
1690 void force_fatal_sig(int sig)
1692 struct kernel_siginfo info;
1694 clear_siginfo(&info);
1695 info.si_signo = sig;
1697 info.si_code = SI_KERNEL;
1700 force_sig_info_to_task(&info, current, HANDLER_SIG_DFL);
1703 void force_exit_sig(int sig)
1705 struct kernel_siginfo info;
1707 clear_siginfo(&info);
1708 info.si_signo = sig;
1710 info.si_code = SI_KERNEL;
1713 force_sig_info_to_task(&info, current, HANDLER_EXIT);
1717 * When things go south during signal handling, we
1718 * will force a SIGSEGV. And if the signal that caused
1719 * the problem was already a SIGSEGV, we'll want to
1720 * make sure we don't even try to deliver the signal..
1722 void force_sigsegv(int sig)
1725 force_fatal_sig(SIGSEGV);
1730 int force_sig_fault_to_task(int sig, int code, void __user *addr
1731 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1732 , struct task_struct *t)
1734 struct kernel_siginfo info;
1736 clear_siginfo(&info);
1737 info.si_signo = sig;
1739 info.si_code = code;
1740 info.si_addr = addr;
1743 info.si_flags = flags;
1746 return force_sig_info_to_task(&info, t, HANDLER_CURRENT);
1749 int force_sig_fault(int sig, int code, void __user *addr
1750 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1752 return force_sig_fault_to_task(sig, code, addr
1753 ___ARCH_SI_IA64(imm, flags, isr), current);
1756 int send_sig_fault(int sig, int code, void __user *addr
1757 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1758 , struct task_struct *t)
1760 struct kernel_siginfo info;
1762 clear_siginfo(&info);
1763 info.si_signo = sig;
1765 info.si_code = code;
1766 info.si_addr = addr;
1769 info.si_flags = flags;
1772 return send_sig_info(info.si_signo, &info, t);
1775 int force_sig_mceerr(int code, void __user *addr, short lsb)
1777 struct kernel_siginfo info;
1779 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1780 clear_siginfo(&info);
1781 info.si_signo = SIGBUS;
1783 info.si_code = code;
1784 info.si_addr = addr;
1785 info.si_addr_lsb = lsb;
1786 return force_sig_info(&info);
1789 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1791 struct kernel_siginfo info;
1793 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1794 clear_siginfo(&info);
1795 info.si_signo = SIGBUS;
1797 info.si_code = code;
1798 info.si_addr = addr;
1799 info.si_addr_lsb = lsb;
1800 return send_sig_info(info.si_signo, &info, t);
1802 EXPORT_SYMBOL(send_sig_mceerr);
1804 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1806 struct kernel_siginfo info;
1808 clear_siginfo(&info);
1809 info.si_signo = SIGSEGV;
1811 info.si_code = SEGV_BNDERR;
1812 info.si_addr = addr;
1813 info.si_lower = lower;
1814 info.si_upper = upper;
1815 return force_sig_info(&info);
1819 int force_sig_pkuerr(void __user *addr, u32 pkey)
1821 struct kernel_siginfo info;
1823 clear_siginfo(&info);
1824 info.si_signo = SIGSEGV;
1826 info.si_code = SEGV_PKUERR;
1827 info.si_addr = addr;
1828 info.si_pkey = pkey;
1829 return force_sig_info(&info);
1833 int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
1835 struct kernel_siginfo info;
1837 clear_siginfo(&info);
1838 info.si_signo = SIGTRAP;
1840 info.si_code = TRAP_PERF;
1841 info.si_addr = addr;
1842 info.si_perf_data = sig_data;
1843 info.si_perf_type = type;
1846 * Signals generated by perf events should not terminate the whole
1847 * process if SIGTRAP is blocked, however, delivering the signal
1848 * asynchronously is better than not delivering at all. But tell user
1849 * space if the signal was asynchronous, so it can clearly be
1850 * distinguished from normal synchronous ones.
1852 info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ?
1853 TRAP_PERF_FLAG_ASYNC :
1856 return send_sig_info(info.si_signo, &info, current);
1860 * force_sig_seccomp - signals the task to allow in-process syscall emulation
1861 * @syscall: syscall number to send to userland
1862 * @reason: filter-supplied reason code to send to userland (via si_errno)
1864 * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
1866 int force_sig_seccomp(int syscall, int reason, bool force_coredump)
1868 struct kernel_siginfo info;
1870 clear_siginfo(&info);
1871 info.si_signo = SIGSYS;
1872 info.si_code = SYS_SECCOMP;
1873 info.si_call_addr = (void __user *)KSTK_EIP(current);
1874 info.si_errno = reason;
1875 info.si_arch = syscall_get_arch(current);
1876 info.si_syscall = syscall;
1877 return force_sig_info_to_task(&info, current,
1878 force_coredump ? HANDLER_EXIT : HANDLER_CURRENT);
1881 /* For the crazy architectures that include trap information in
1882 * the errno field, instead of an actual errno value.
1884 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1886 struct kernel_siginfo info;
1888 clear_siginfo(&info);
1889 info.si_signo = SIGTRAP;
1890 info.si_errno = errno;
1891 info.si_code = TRAP_HWBKPT;
1892 info.si_addr = addr;
1893 return force_sig_info(&info);
1896 /* For the rare architectures that include trap information using
1899 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
1901 struct kernel_siginfo info;
1903 clear_siginfo(&info);
1904 info.si_signo = sig;
1906 info.si_code = code;
1907 info.si_addr = addr;
1908 info.si_trapno = trapno;
1909 return force_sig_info(&info);
1912 /* For the rare architectures that include trap information using
1915 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
1916 struct task_struct *t)
1918 struct kernel_siginfo info;
1920 clear_siginfo(&info);
1921 info.si_signo = sig;
1923 info.si_code = code;
1924 info.si_addr = addr;
1925 info.si_trapno = trapno;
1926 return send_sig_info(info.si_signo, &info, t);
1929 int kill_pgrp(struct pid *pid, int sig, int priv)
1933 read_lock(&tasklist_lock);
1934 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1935 read_unlock(&tasklist_lock);
1939 EXPORT_SYMBOL(kill_pgrp);
1941 int kill_pid(struct pid *pid, int sig, int priv)
1943 return kill_pid_info(sig, __si_special(priv), pid);
1945 EXPORT_SYMBOL(kill_pid);
1948 * These functions support sending signals using preallocated sigqueue
1949 * structures. This is needed "because realtime applications cannot
1950 * afford to lose notifications of asynchronous events, like timer
1951 * expirations or I/O completions". In the case of POSIX Timers
1952 * we allocate the sigqueue structure from the timer_create. If this
1953 * allocation fails we are able to report the failure to the application
1954 * with an EAGAIN error.
1956 struct sigqueue *sigqueue_alloc(void)
1958 return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
1961 void sigqueue_free(struct sigqueue *q)
1963 unsigned long flags;
1964 spinlock_t *lock = ¤t->sighand->siglock;
1966 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1968 * We must hold ->siglock while testing q->list
1969 * to serialize with collect_signal() or with
1970 * __exit_signal()->flush_sigqueue().
1972 spin_lock_irqsave(lock, flags);
1973 q->flags &= ~SIGQUEUE_PREALLOC;
1975 * If it is queued it will be freed when dequeued,
1976 * like the "regular" sigqueue.
1978 if (!list_empty(&q->list))
1980 spin_unlock_irqrestore(lock, flags);
1986 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1988 int sig = q->info.si_signo;
1989 struct sigpending *pending;
1990 struct task_struct *t;
1991 unsigned long flags;
1994 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1998 t = pid_task(pid, type);
1999 if (!t || !likely(lock_task_sighand(t, &flags)))
2002 ret = 1; /* the signal is ignored */
2003 result = TRACE_SIGNAL_IGNORED;
2004 if (!prepare_signal(sig, t, false))
2008 if (unlikely(!list_empty(&q->list))) {
2010 * If an SI_TIMER entry is already queue just increment
2011 * the overrun count.
2013 BUG_ON(q->info.si_code != SI_TIMER);
2014 q->info.si_overrun++;
2015 result = TRACE_SIGNAL_ALREADY_PENDING;
2018 q->info.si_overrun = 0;
2020 signalfd_notify(t, sig);
2021 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
2022 list_add_tail(&q->list, &pending->list);
2023 sigaddset(&pending->signal, sig);
2024 complete_signal(sig, t, type);
2025 result = TRACE_SIGNAL_DELIVERED;
2027 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
2028 unlock_task_sighand(t, &flags);
2034 static void do_notify_pidfd(struct task_struct *task)
2038 WARN_ON(task->exit_state == 0);
2039 pid = task_pid(task);
2040 wake_up_all(&pid->wait_pidfd);
2044 * Let a parent know about the death of a child.
2045 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
2047 * Returns true if our parent ignored us and so we've switched to
2050 bool do_notify_parent(struct task_struct *tsk, int sig)
2052 struct kernel_siginfo info;
2053 unsigned long flags;
2054 struct sighand_struct *psig;
2055 bool autoreap = false;
2058 WARN_ON_ONCE(sig == -1);
2060 /* do_notify_parent_cldstop should have been called instead. */
2061 WARN_ON_ONCE(task_is_stopped_or_traced(tsk));
2063 WARN_ON_ONCE(!tsk->ptrace &&
2064 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
2066 /* Wake up all pidfd waiters */
2067 do_notify_pidfd(tsk);
2069 if (sig != SIGCHLD) {
2071 * This is only possible if parent == real_parent.
2072 * Check if it has changed security domain.
2074 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
2078 clear_siginfo(&info);
2079 info.si_signo = sig;
2082 * We are under tasklist_lock here so our parent is tied to
2083 * us and cannot change.
2085 * task_active_pid_ns will always return the same pid namespace
2086 * until a task passes through release_task.
2088 * write_lock() currently calls preempt_disable() which is the
2089 * same as rcu_read_lock(), but according to Oleg, this is not
2090 * correct to rely on this
2093 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
2094 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
2098 task_cputime(tsk, &utime, &stime);
2099 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
2100 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
2102 info.si_status = tsk->exit_code & 0x7f;
2103 if (tsk->exit_code & 0x80)
2104 info.si_code = CLD_DUMPED;
2105 else if (tsk->exit_code & 0x7f)
2106 info.si_code = CLD_KILLED;
2108 info.si_code = CLD_EXITED;
2109 info.si_status = tsk->exit_code >> 8;
2112 psig = tsk->parent->sighand;
2113 spin_lock_irqsave(&psig->siglock, flags);
2114 if (!tsk->ptrace && sig == SIGCHLD &&
2115 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
2116 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
2118 * We are exiting and our parent doesn't care. POSIX.1
2119 * defines special semantics for setting SIGCHLD to SIG_IGN
2120 * or setting the SA_NOCLDWAIT flag: we should be reaped
2121 * automatically and not left for our parent's wait4 call.
2122 * Rather than having the parent do it as a magic kind of
2123 * signal handler, we just set this to tell do_exit that we
2124 * can be cleaned up without becoming a zombie. Note that
2125 * we still call __wake_up_parent in this case, because a
2126 * blocked sys_wait4 might now return -ECHILD.
2128 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
2129 * is implementation-defined: we do (if you don't want
2130 * it, just use SIG_IGN instead).
2133 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
2137 * Send with __send_signal as si_pid and si_uid are in the
2138 * parent's namespaces.
2140 if (valid_signal(sig) && sig)
2141 __send_signal(sig, &info, tsk->parent, PIDTYPE_TGID, false);
2142 __wake_up_parent(tsk, tsk->parent);
2143 spin_unlock_irqrestore(&psig->siglock, flags);
2149 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2150 * @tsk: task reporting the state change
2151 * @for_ptracer: the notification is for ptracer
2152 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2154 * Notify @tsk's parent that the stopped/continued state has changed. If
2155 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2156 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2159 * Must be called with tasklist_lock at least read locked.
2161 static void do_notify_parent_cldstop(struct task_struct *tsk,
2162 bool for_ptracer, int why)
2164 struct kernel_siginfo info;
2165 unsigned long flags;
2166 struct task_struct *parent;
2167 struct sighand_struct *sighand;
2171 parent = tsk->parent;
2173 tsk = tsk->group_leader;
2174 parent = tsk->real_parent;
2177 clear_siginfo(&info);
2178 info.si_signo = SIGCHLD;
2181 * see comment in do_notify_parent() about the following 4 lines
2184 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2185 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2188 task_cputime(tsk, &utime, &stime);
2189 info.si_utime = nsec_to_clock_t(utime);
2190 info.si_stime = nsec_to_clock_t(stime);
2195 info.si_status = SIGCONT;
2198 info.si_status = tsk->signal->group_exit_code & 0x7f;
2201 info.si_status = tsk->exit_code & 0x7f;
2207 sighand = parent->sighand;
2208 spin_lock_irqsave(&sighand->siglock, flags);
2209 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2210 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2211 __group_send_sig_info(SIGCHLD, &info, parent);
2213 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2215 __wake_up_parent(tsk, parent);
2216 spin_unlock_irqrestore(&sighand->siglock, flags);
2219 static inline bool may_ptrace_stop(void)
2221 if (!likely(current->ptrace))
2224 * Are we in the middle of do_coredump?
2225 * If so and our tracer is also part of the coredump stopping
2226 * is a deadlock situation, and pointless because our tracer
2227 * is dead so don't allow us to stop.
2228 * If SIGKILL was already sent before the caller unlocked
2229 * ->siglock we must see ->core_state != NULL. Otherwise it
2230 * is safe to enter schedule().
2232 * This is almost outdated, a task with the pending SIGKILL can't
2233 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2234 * after SIGKILL was already dequeued.
2236 if (unlikely(current->mm->core_state) &&
2237 unlikely(current->mm == current->parent->mm))
2245 * This must be called with current->sighand->siglock held.
2247 * This should be the path for all ptrace stops.
2248 * We always set current->last_siginfo while stopped here.
2249 * That makes it a way to test a stopped process for
2250 * being ptrace-stopped vs being job-control-stopped.
2252 * If we actually decide not to stop at all because the tracer
2253 * is gone, we keep current->exit_code unless clear_code.
2255 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2256 __releases(¤t->sighand->siglock)
2257 __acquires(¤t->sighand->siglock)
2259 bool gstop_done = false;
2261 if (arch_ptrace_stop_needed(exit_code, info)) {
2263 * The arch code has something special to do before a
2264 * ptrace stop. This is allowed to block, e.g. for faults
2265 * on user stack pages. We can't keep the siglock while
2266 * calling arch_ptrace_stop, so we must release it now.
2267 * To preserve proper semantics, we must do this before
2268 * any signal bookkeeping like checking group_stop_count.
2270 spin_unlock_irq(¤t->sighand->siglock);
2271 arch_ptrace_stop(exit_code, info);
2272 spin_lock_irq(¤t->sighand->siglock);
2276 * schedule() will not sleep if there is a pending signal that
2277 * can awaken the task.
2279 set_special_state(TASK_TRACED);
2282 * We're committing to trapping. TRACED should be visible before
2283 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2284 * Also, transition to TRACED and updates to ->jobctl should be
2285 * atomic with respect to siglock and should be done after the arch
2286 * hook as siglock is released and regrabbed across it.
2291 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2293 * set_current_state() smp_wmb();
2295 * wait_task_stopped()
2296 * task_stopped_code()
2297 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2301 current->last_siginfo = info;
2302 current->exit_code = exit_code;
2305 * If @why is CLD_STOPPED, we're trapping to participate in a group
2306 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2307 * across siglock relocks since INTERRUPT was scheduled, PENDING
2308 * could be clear now. We act as if SIGCONT is received after
2309 * TASK_TRACED is entered - ignore it.
2311 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2312 gstop_done = task_participate_group_stop(current);
2314 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2315 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2316 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2317 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2319 /* entering a trap, clear TRAPPING */
2320 task_clear_jobctl_trapping(current);
2322 spin_unlock_irq(¤t->sighand->siglock);
2323 read_lock(&tasklist_lock);
2324 if (may_ptrace_stop()) {
2326 * Notify parents of the stop.
2328 * While ptraced, there are two parents - the ptracer and
2329 * the real_parent of the group_leader. The ptracer should
2330 * know about every stop while the real parent is only
2331 * interested in the completion of group stop. The states
2332 * for the two don't interact with each other. Notify
2333 * separately unless they're gonna be duplicates.
2335 do_notify_parent_cldstop(current, true, why);
2336 if (gstop_done && ptrace_reparented(current))
2337 do_notify_parent_cldstop(current, false, why);
2339 read_unlock(&tasklist_lock);
2340 cgroup_enter_frozen();
2341 freezable_schedule();
2342 cgroup_leave_frozen(true);
2345 * By the time we got the lock, our tracer went away.
2346 * Don't drop the lock yet, another tracer may come.
2348 * If @gstop_done, the ptracer went away between group stop
2349 * completion and here. During detach, it would have set
2350 * JOBCTL_STOP_PENDING on us and we'll re-enter
2351 * TASK_STOPPED in do_signal_stop() on return, so notifying
2352 * the real parent of the group stop completion is enough.
2355 do_notify_parent_cldstop(current, false, why);
2357 /* tasklist protects us from ptrace_freeze_traced() */
2358 __set_current_state(TASK_RUNNING);
2360 current->exit_code = 0;
2361 read_unlock(&tasklist_lock);
2365 * We are back. Now reacquire the siglock before touching
2366 * last_siginfo, so that we are sure to have synchronized with
2367 * any signal-sending on another CPU that wants to examine it.
2369 spin_lock_irq(¤t->sighand->siglock);
2370 current->last_siginfo = NULL;
2372 /* LISTENING can be set only during STOP traps, clear it */
2373 current->jobctl &= ~JOBCTL_LISTENING;
2376 * Queued signals ignored us while we were stopped for tracing.
2377 * So check for any that we should take before resuming user mode.
2378 * This sets TIF_SIGPENDING, but never clears it.
2380 recalc_sigpending_tsk(current);
2383 static void ptrace_do_notify(int signr, int exit_code, int why)
2385 kernel_siginfo_t info;
2387 clear_siginfo(&info);
2388 info.si_signo = signr;
2389 info.si_code = exit_code;
2390 info.si_pid = task_pid_vnr(current);
2391 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2393 /* Let the debugger run. */
2394 ptrace_stop(exit_code, why, 1, &info);
2397 void ptrace_notify(int exit_code)
2399 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2400 if (unlikely(current->task_works))
2403 spin_lock_irq(¤t->sighand->siglock);
2404 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2405 spin_unlock_irq(¤t->sighand->siglock);
2409 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2410 * @signr: signr causing group stop if initiating
2412 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2413 * and participate in it. If already set, participate in the existing
2414 * group stop. If participated in a group stop (and thus slept), %true is
2415 * returned with siglock released.
2417 * If ptraced, this function doesn't handle stop itself. Instead,
2418 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2419 * untouched. The caller must ensure that INTERRUPT trap handling takes
2420 * places afterwards.
2423 * Must be called with @current->sighand->siglock held, which is released
2427 * %false if group stop is already cancelled or ptrace trap is scheduled.
2428 * %true if participated in group stop.
2430 static bool do_signal_stop(int signr)
2431 __releases(¤t->sighand->siglock)
2433 struct signal_struct *sig = current->signal;
2435 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2436 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2437 struct task_struct *t;
2439 /* signr will be recorded in task->jobctl for retries */
2440 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2442 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2443 unlikely(signal_group_exit(sig)))
2446 * There is no group stop already in progress. We must
2449 * While ptraced, a task may be resumed while group stop is
2450 * still in effect and then receive a stop signal and
2451 * initiate another group stop. This deviates from the
2452 * usual behavior as two consecutive stop signals can't
2453 * cause two group stops when !ptraced. That is why we
2454 * also check !task_is_stopped(t) below.
2456 * The condition can be distinguished by testing whether
2457 * SIGNAL_STOP_STOPPED is already set. Don't generate
2458 * group_exit_code in such case.
2460 * This is not necessary for SIGNAL_STOP_CONTINUED because
2461 * an intervening stop signal is required to cause two
2462 * continued events regardless of ptrace.
2464 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2465 sig->group_exit_code = signr;
2467 sig->group_stop_count = 0;
2469 if (task_set_jobctl_pending(current, signr | gstop))
2470 sig->group_stop_count++;
2473 while_each_thread(current, t) {
2475 * Setting state to TASK_STOPPED for a group
2476 * stop is always done with the siglock held,
2477 * so this check has no races.
2479 if (!task_is_stopped(t) &&
2480 task_set_jobctl_pending(t, signr | gstop)) {
2481 sig->group_stop_count++;
2482 if (likely(!(t->ptrace & PT_SEIZED)))
2483 signal_wake_up(t, 0);
2485 ptrace_trap_notify(t);
2490 if (likely(!current->ptrace)) {
2494 * If there are no other threads in the group, or if there
2495 * is a group stop in progress and we are the last to stop,
2496 * report to the parent.
2498 if (task_participate_group_stop(current))
2499 notify = CLD_STOPPED;
2501 set_special_state(TASK_STOPPED);
2502 spin_unlock_irq(¤t->sighand->siglock);
2505 * Notify the parent of the group stop completion. Because
2506 * we're not holding either the siglock or tasklist_lock
2507 * here, ptracer may attach inbetween; however, this is for
2508 * group stop and should always be delivered to the real
2509 * parent of the group leader. The new ptracer will get
2510 * its notification when this task transitions into
2514 read_lock(&tasklist_lock);
2515 do_notify_parent_cldstop(current, false, notify);
2516 read_unlock(&tasklist_lock);
2519 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2520 cgroup_enter_frozen();
2521 freezable_schedule();
2525 * While ptraced, group stop is handled by STOP trap.
2526 * Schedule it and let the caller deal with it.
2528 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2534 * do_jobctl_trap - take care of ptrace jobctl traps
2536 * When PT_SEIZED, it's used for both group stop and explicit
2537 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2538 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2539 * the stop signal; otherwise, %SIGTRAP.
2541 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2542 * number as exit_code and no siginfo.
2545 * Must be called with @current->sighand->siglock held, which may be
2546 * released and re-acquired before returning with intervening sleep.
2548 static void do_jobctl_trap(void)
2550 struct signal_struct *signal = current->signal;
2551 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2553 if (current->ptrace & PT_SEIZED) {
2554 if (!signal->group_stop_count &&
2555 !(signal->flags & SIGNAL_STOP_STOPPED))
2557 WARN_ON_ONCE(!signr);
2558 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2561 WARN_ON_ONCE(!signr);
2562 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2563 current->exit_code = 0;
2568 * do_freezer_trap - handle the freezer jobctl trap
2570 * Puts the task into frozen state, if only the task is not about to quit.
2571 * In this case it drops JOBCTL_TRAP_FREEZE.
2574 * Must be called with @current->sighand->siglock held,
2575 * which is always released before returning.
2577 static void do_freezer_trap(void)
2578 __releases(¤t->sighand->siglock)
2581 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2582 * let's make another loop to give it a chance to be handled.
2583 * In any case, we'll return back.
2585 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2586 JOBCTL_TRAP_FREEZE) {
2587 spin_unlock_irq(¤t->sighand->siglock);
2592 * Now we're sure that there is no pending fatal signal and no
2593 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2594 * immediately (if there is a non-fatal signal pending), and
2595 * put the task into sleep.
2597 __set_current_state(TASK_INTERRUPTIBLE);
2598 clear_thread_flag(TIF_SIGPENDING);
2599 spin_unlock_irq(¤t->sighand->siglock);
2600 cgroup_enter_frozen();
2601 freezable_schedule();
2604 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2607 * We do not check sig_kernel_stop(signr) but set this marker
2608 * unconditionally because we do not know whether debugger will
2609 * change signr. This flag has no meaning unless we are going
2610 * to stop after return from ptrace_stop(). In this case it will
2611 * be checked in do_signal_stop(), we should only stop if it was
2612 * not cleared by SIGCONT while we were sleeping. See also the
2613 * comment in dequeue_signal().
2615 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2616 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2618 /* We're back. Did the debugger cancel the sig? */
2619 signr = current->exit_code;
2623 current->exit_code = 0;
2626 * Update the siginfo structure if the signal has
2627 * changed. If the debugger wanted something
2628 * specific in the siginfo structure then it should
2629 * have updated *info via PTRACE_SETSIGINFO.
2631 if (signr != info->si_signo) {
2632 clear_siginfo(info);
2633 info->si_signo = signr;
2635 info->si_code = SI_USER;
2637 info->si_pid = task_pid_vnr(current->parent);
2638 info->si_uid = from_kuid_munged(current_user_ns(),
2639 task_uid(current->parent));
2643 /* If the (new) signal is now blocked, requeue it. */
2644 if (sigismember(¤t->blocked, signr)) {
2645 send_signal(signr, info, current, PIDTYPE_PID);
2652 static void hide_si_addr_tag_bits(struct ksignal *ksig)
2654 switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
2656 case SIL_FAULT_TRAPNO:
2657 case SIL_FAULT_MCEERR:
2658 case SIL_FAULT_BNDERR:
2659 case SIL_FAULT_PKUERR:
2660 case SIL_FAULT_PERF_EVENT:
2661 ksig->info.si_addr = arch_untagged_si_addr(
2662 ksig->info.si_addr, ksig->sig, ksig->info.si_code);
2674 bool get_signal(struct ksignal *ksig)
2676 struct sighand_struct *sighand = current->sighand;
2677 struct signal_struct *signal = current->signal;
2680 if (unlikely(current->task_works))
2684 * For non-generic architectures, check for TIF_NOTIFY_SIGNAL so
2685 * that the arch handlers don't all have to do it. If we get here
2686 * without TIF_SIGPENDING, just exit after running signal work.
2688 if (!IS_ENABLED(CONFIG_GENERIC_ENTRY)) {
2689 if (test_thread_flag(TIF_NOTIFY_SIGNAL))
2690 tracehook_notify_signal();
2691 if (!task_sigpending(current))
2695 if (unlikely(uprobe_deny_signal()))
2699 * Do this once, we can't return to user-mode if freezing() == T.
2700 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2701 * thus do not need another check after return.
2706 spin_lock_irq(&sighand->siglock);
2709 * Every stopped thread goes here after wakeup. Check to see if
2710 * we should notify the parent, prepare_signal(SIGCONT) encodes
2711 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2713 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2716 if (signal->flags & SIGNAL_CLD_CONTINUED)
2717 why = CLD_CONTINUED;
2721 signal->flags &= ~SIGNAL_CLD_MASK;
2723 spin_unlock_irq(&sighand->siglock);
2726 * Notify the parent that we're continuing. This event is
2727 * always per-process and doesn't make whole lot of sense
2728 * for ptracers, who shouldn't consume the state via
2729 * wait(2) either, but, for backward compatibility, notify
2730 * the ptracer of the group leader too unless it's gonna be
2733 read_lock(&tasklist_lock);
2734 do_notify_parent_cldstop(current, false, why);
2736 if (ptrace_reparented(current->group_leader))
2737 do_notify_parent_cldstop(current->group_leader,
2739 read_unlock(&tasklist_lock);
2745 struct k_sigaction *ka;
2747 /* Has this task already been marked for death? */
2748 if (signal_group_exit(signal)) {
2749 ksig->info.si_signo = signr = SIGKILL;
2750 sigdelset(¤t->pending.signal, SIGKILL);
2751 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2752 &sighand->action[SIGKILL - 1]);
2753 recalc_sigpending();
2757 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2761 if (unlikely(current->jobctl &
2762 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2763 if (current->jobctl & JOBCTL_TRAP_MASK) {
2765 spin_unlock_irq(&sighand->siglock);
2766 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2773 * If the task is leaving the frozen state, let's update
2774 * cgroup counters and reset the frozen bit.
2776 if (unlikely(cgroup_task_frozen(current))) {
2777 spin_unlock_irq(&sighand->siglock);
2778 cgroup_leave_frozen(false);
2783 * Signals generated by the execution of an instruction
2784 * need to be delivered before any other pending signals
2785 * so that the instruction pointer in the signal stack
2786 * frame points to the faulting instruction.
2788 signr = dequeue_synchronous_signal(&ksig->info);
2790 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2793 break; /* will return 0 */
2795 if (unlikely(current->ptrace) && (signr != SIGKILL) &&
2796 !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) {
2797 signr = ptrace_signal(signr, &ksig->info);
2802 ka = &sighand->action[signr-1];
2804 /* Trace actually delivered signals. */
2805 trace_signal_deliver(signr, &ksig->info, ka);
2807 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2809 if (ka->sa.sa_handler != SIG_DFL) {
2810 /* Run the handler. */
2813 if (ka->sa.sa_flags & SA_ONESHOT)
2814 ka->sa.sa_handler = SIG_DFL;
2816 break; /* will return non-zero "signr" value */
2820 * Now we are doing the default action for this signal.
2822 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2826 * Global init gets no signals it doesn't want.
2827 * Container-init gets no signals it doesn't want from same
2830 * Note that if global/container-init sees a sig_kernel_only()
2831 * signal here, the signal must have been generated internally
2832 * or must have come from an ancestor namespace. In either
2833 * case, the signal cannot be dropped.
2835 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2836 !sig_kernel_only(signr))
2839 if (sig_kernel_stop(signr)) {
2841 * The default action is to stop all threads in
2842 * the thread group. The job control signals
2843 * do nothing in an orphaned pgrp, but SIGSTOP
2844 * always works. Note that siglock needs to be
2845 * dropped during the call to is_orphaned_pgrp()
2846 * because of lock ordering with tasklist_lock.
2847 * This allows an intervening SIGCONT to be posted.
2848 * We need to check for that and bail out if necessary.
2850 if (signr != SIGSTOP) {
2851 spin_unlock_irq(&sighand->siglock);
2853 /* signals can be posted during this window */
2855 if (is_current_pgrp_orphaned())
2858 spin_lock_irq(&sighand->siglock);
2861 if (likely(do_signal_stop(ksig->info.si_signo))) {
2862 /* It released the siglock. */
2867 * We didn't actually stop, due to a race
2868 * with SIGCONT or something like that.
2874 spin_unlock_irq(&sighand->siglock);
2875 if (unlikely(cgroup_task_frozen(current)))
2876 cgroup_leave_frozen(true);
2879 * Anything else is fatal, maybe with a core dump.
2881 current->flags |= PF_SIGNALED;
2883 if (sig_kernel_coredump(signr)) {
2884 if (print_fatal_signals)
2885 print_fatal_signal(ksig->info.si_signo);
2886 proc_coredump_connector(current);
2888 * If it was able to dump core, this kills all
2889 * other threads in the group and synchronizes with
2890 * their demise. If we lost the race with another
2891 * thread getting here, it set group_exit_code
2892 * first and our do_group_exit call below will use
2893 * that value and ignore the one we pass it.
2895 do_coredump(&ksig->info);
2899 * PF_IO_WORKER threads will catch and exit on fatal signals
2900 * themselves. They have cleanup that must be performed, so
2901 * we cannot call do_exit() on their behalf.
2903 if (current->flags & PF_IO_WORKER)
2907 * Death signals, no core dump.
2909 do_group_exit(ksig->info.si_signo);
2912 spin_unlock_irq(&sighand->siglock);
2916 if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
2917 hide_si_addr_tag_bits(ksig);
2919 return ksig->sig > 0;
2923 * signal_delivered -
2924 * @ksig: kernel signal struct
2925 * @stepping: nonzero if debugger single-step or block-step in use
2927 * This function should be called when a signal has successfully been
2928 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2929 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2930 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2932 static void signal_delivered(struct ksignal *ksig, int stepping)
2936 /* A signal was successfully delivered, and the
2937 saved sigmask was stored on the signal frame,
2938 and will be restored by sigreturn. So we can
2939 simply clear the restore sigmask flag. */
2940 clear_restore_sigmask();
2942 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2943 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2944 sigaddset(&blocked, ksig->sig);
2945 set_current_blocked(&blocked);
2946 if (current->sas_ss_flags & SS_AUTODISARM)
2947 sas_ss_reset(current);
2948 tracehook_signal_handler(stepping);
2951 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2954 force_sigsegv(ksig->sig);
2956 signal_delivered(ksig, stepping);
2960 * It could be that complete_signal() picked us to notify about the
2961 * group-wide signal. Other threads should be notified now to take
2962 * the shared signals in @which since we will not.
2964 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2967 struct task_struct *t;
2969 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2970 if (sigisemptyset(&retarget))
2974 while_each_thread(tsk, t) {
2975 if (t->flags & PF_EXITING)
2978 if (!has_pending_signals(&retarget, &t->blocked))
2980 /* Remove the signals this thread can handle. */
2981 sigandsets(&retarget, &retarget, &t->blocked);
2983 if (!task_sigpending(t))
2984 signal_wake_up(t, 0);
2986 if (sigisemptyset(&retarget))
2991 void exit_signals(struct task_struct *tsk)
2997 * @tsk is about to have PF_EXITING set - lock out users which
2998 * expect stable threadgroup.
3000 cgroup_threadgroup_change_begin(tsk);
3002 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
3003 tsk->flags |= PF_EXITING;
3004 cgroup_threadgroup_change_end(tsk);
3008 spin_lock_irq(&tsk->sighand->siglock);
3010 * From now this task is not visible for group-wide signals,
3011 * see wants_signal(), do_signal_stop().
3013 tsk->flags |= PF_EXITING;
3015 cgroup_threadgroup_change_end(tsk);
3017 if (!task_sigpending(tsk))
3020 unblocked = tsk->blocked;
3021 signotset(&unblocked);
3022 retarget_shared_pending(tsk, &unblocked);
3024 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
3025 task_participate_group_stop(tsk))
3026 group_stop = CLD_STOPPED;
3028 spin_unlock_irq(&tsk->sighand->siglock);
3031 * If group stop has completed, deliver the notification. This
3032 * should always go to the real parent of the group leader.
3034 if (unlikely(group_stop)) {
3035 read_lock(&tasklist_lock);
3036 do_notify_parent_cldstop(tsk, false, group_stop);
3037 read_unlock(&tasklist_lock);
3042 * System call entry points.
3046 * sys_restart_syscall - restart a system call
3048 SYSCALL_DEFINE0(restart_syscall)
3050 struct restart_block *restart = ¤t->restart_block;
3051 return restart->fn(restart);
3054 long do_no_restart_syscall(struct restart_block *param)
3059 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
3061 if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
3062 sigset_t newblocked;
3063 /* A set of now blocked but previously unblocked signals. */
3064 sigandnsets(&newblocked, newset, ¤t->blocked);
3065 retarget_shared_pending(tsk, &newblocked);
3067 tsk->blocked = *newset;
3068 recalc_sigpending();
3072 * set_current_blocked - change current->blocked mask
3075 * It is wrong to change ->blocked directly, this helper should be used
3076 * to ensure the process can't miss a shared signal we are going to block.
3078 void set_current_blocked(sigset_t *newset)
3080 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
3081 __set_current_blocked(newset);
3084 void __set_current_blocked(const sigset_t *newset)
3086 struct task_struct *tsk = current;
3089 * In case the signal mask hasn't changed, there is nothing we need
3090 * to do. The current->blocked shouldn't be modified by other task.
3092 if (sigequalsets(&tsk->blocked, newset))
3095 spin_lock_irq(&tsk->sighand->siglock);
3096 __set_task_blocked(tsk, newset);
3097 spin_unlock_irq(&tsk->sighand->siglock);
3101 * This is also useful for kernel threads that want to temporarily
3102 * (or permanently) block certain signals.
3104 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
3105 * interface happily blocks "unblockable" signals like SIGKILL
3108 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
3110 struct task_struct *tsk = current;
3113 /* Lockless, only current can change ->blocked, never from irq */
3115 *oldset = tsk->blocked;
3119 sigorsets(&newset, &tsk->blocked, set);
3122 sigandnsets(&newset, &tsk->blocked, set);
3131 __set_current_blocked(&newset);
3134 EXPORT_SYMBOL(sigprocmask);
3137 * The api helps set app-provided sigmasks.
3139 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
3140 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
3142 * Note that it does set_restore_sigmask() in advance, so it must be always
3143 * paired with restore_saved_sigmask_unless() before return from syscall.
3145 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
3151 if (sigsetsize != sizeof(sigset_t))
3153 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
3156 set_restore_sigmask();
3157 current->saved_sigmask = current->blocked;
3158 set_current_blocked(&kmask);
3163 #ifdef CONFIG_COMPAT
3164 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3171 if (sigsetsize != sizeof(compat_sigset_t))
3173 if (get_compat_sigset(&kmask, umask))
3176 set_restore_sigmask();
3177 current->saved_sigmask = current->blocked;
3178 set_current_blocked(&kmask);
3185 * sys_rt_sigprocmask - change the list of currently blocked signals
3186 * @how: whether to add, remove, or set signals
3187 * @nset: stores pending signals
3188 * @oset: previous value of signal mask if non-null
3189 * @sigsetsize: size of sigset_t type
3191 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3192 sigset_t __user *, oset, size_t, sigsetsize)
3194 sigset_t old_set, new_set;
3197 /* XXX: Don't preclude handling different sized sigset_t's. */
3198 if (sigsetsize != sizeof(sigset_t))
3201 old_set = current->blocked;
3204 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3206 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3208 error = sigprocmask(how, &new_set, NULL);
3214 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3221 #ifdef CONFIG_COMPAT
3222 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3223 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3225 sigset_t old_set = current->blocked;
3227 /* XXX: Don't preclude handling different sized sigset_t's. */
3228 if (sigsetsize != sizeof(sigset_t))
3234 if (get_compat_sigset(&new_set, nset))
3236 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3238 error = sigprocmask(how, &new_set, NULL);
3242 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3246 static void do_sigpending(sigset_t *set)
3248 spin_lock_irq(¤t->sighand->siglock);
3249 sigorsets(set, ¤t->pending.signal,
3250 ¤t->signal->shared_pending.signal);
3251 spin_unlock_irq(¤t->sighand->siglock);
3253 /* Outside the lock because only this thread touches it. */
3254 sigandsets(set, ¤t->blocked, set);
3258 * sys_rt_sigpending - examine a pending signal that has been raised
3260 * @uset: stores pending signals
3261 * @sigsetsize: size of sigset_t type or larger
3263 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3267 if (sigsetsize > sizeof(*uset))
3270 do_sigpending(&set);
3272 if (copy_to_user(uset, &set, sigsetsize))
3278 #ifdef CONFIG_COMPAT
3279 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3280 compat_size_t, sigsetsize)
3284 if (sigsetsize > sizeof(*uset))
3287 do_sigpending(&set);
3289 return put_compat_sigset(uset, &set, sigsetsize);
3293 static const struct {
3294 unsigned char limit, layout;
3296 [SIGILL] = { NSIGILL, SIL_FAULT },
3297 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3298 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3299 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3300 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3302 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3304 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3305 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3306 [SIGSYS] = { NSIGSYS, SIL_SYS },
3309 static bool known_siginfo_layout(unsigned sig, int si_code)
3311 if (si_code == SI_KERNEL)
3313 else if ((si_code > SI_USER)) {
3314 if (sig_specific_sicodes(sig)) {
3315 if (si_code <= sig_sicodes[sig].limit)
3318 else if (si_code <= NSIGPOLL)
3321 else if (si_code >= SI_DETHREAD)
3323 else if (si_code == SI_ASYNCNL)
3328 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3330 enum siginfo_layout layout = SIL_KILL;
3331 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3332 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3333 (si_code <= sig_sicodes[sig].limit)) {
3334 layout = sig_sicodes[sig].layout;
3335 /* Handle the exceptions */
3336 if ((sig == SIGBUS) &&
3337 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3338 layout = SIL_FAULT_MCEERR;
3339 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3340 layout = SIL_FAULT_BNDERR;
3342 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3343 layout = SIL_FAULT_PKUERR;
3345 else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
3346 layout = SIL_FAULT_PERF_EVENT;
3347 else if (IS_ENABLED(CONFIG_SPARC) &&
3348 (sig == SIGILL) && (si_code == ILL_ILLTRP))
3349 layout = SIL_FAULT_TRAPNO;
3350 else if (IS_ENABLED(CONFIG_ALPHA) &&
3352 ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
3353 layout = SIL_FAULT_TRAPNO;
3355 else if (si_code <= NSIGPOLL)
3358 if (si_code == SI_TIMER)
3360 else if (si_code == SI_SIGIO)
3362 else if (si_code < 0)
3368 static inline char __user *si_expansion(const siginfo_t __user *info)
3370 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3373 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3375 char __user *expansion = si_expansion(to);
3376 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3378 if (clear_user(expansion, SI_EXPANSION_SIZE))
3383 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3384 const siginfo_t __user *from)
3386 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3387 char __user *expansion = si_expansion(from);
3388 char buf[SI_EXPANSION_SIZE];
3391 * An unknown si_code might need more than
3392 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3393 * extra bytes are 0. This guarantees copy_siginfo_to_user
3394 * will return this data to userspace exactly.
3396 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3398 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3406 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3407 const siginfo_t __user *from)
3409 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3411 to->si_signo = signo;
3412 return post_copy_siginfo_from_user(to, from);
3415 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3417 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3419 return post_copy_siginfo_from_user(to, from);
3422 #ifdef CONFIG_COMPAT
3424 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3425 * @to: compat siginfo destination
3426 * @from: kernel siginfo source
3428 * Note: This function does not work properly for the SIGCHLD on x32, but
3429 * fortunately it doesn't have to. The only valid callers for this function are
3430 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3431 * The latter does not care because SIGCHLD will never cause a coredump.
3433 void copy_siginfo_to_external32(struct compat_siginfo *to,
3434 const struct kernel_siginfo *from)
3436 memset(to, 0, sizeof(*to));
3438 to->si_signo = from->si_signo;
3439 to->si_errno = from->si_errno;
3440 to->si_code = from->si_code;
3441 switch(siginfo_layout(from->si_signo, from->si_code)) {
3443 to->si_pid = from->si_pid;
3444 to->si_uid = from->si_uid;
3447 to->si_tid = from->si_tid;
3448 to->si_overrun = from->si_overrun;
3449 to->si_int = from->si_int;
3452 to->si_band = from->si_band;
3453 to->si_fd = from->si_fd;
3456 to->si_addr = ptr_to_compat(from->si_addr);
3458 case SIL_FAULT_TRAPNO:
3459 to->si_addr = ptr_to_compat(from->si_addr);
3460 to->si_trapno = from->si_trapno;
3462 case SIL_FAULT_MCEERR:
3463 to->si_addr = ptr_to_compat(from->si_addr);
3464 to->si_addr_lsb = from->si_addr_lsb;
3466 case SIL_FAULT_BNDERR:
3467 to->si_addr = ptr_to_compat(from->si_addr);
3468 to->si_lower = ptr_to_compat(from->si_lower);
3469 to->si_upper = ptr_to_compat(from->si_upper);
3471 case SIL_FAULT_PKUERR:
3472 to->si_addr = ptr_to_compat(from->si_addr);
3473 to->si_pkey = from->si_pkey;
3475 case SIL_FAULT_PERF_EVENT:
3476 to->si_addr = ptr_to_compat(from->si_addr);
3477 to->si_perf_data = from->si_perf_data;
3478 to->si_perf_type = from->si_perf_type;
3479 to->si_perf_flags = from->si_perf_flags;
3482 to->si_pid = from->si_pid;
3483 to->si_uid = from->si_uid;
3484 to->si_status = from->si_status;
3485 to->si_utime = from->si_utime;
3486 to->si_stime = from->si_stime;
3489 to->si_pid = from->si_pid;
3490 to->si_uid = from->si_uid;
3491 to->si_int = from->si_int;
3494 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3495 to->si_syscall = from->si_syscall;
3496 to->si_arch = from->si_arch;
3501 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3502 const struct kernel_siginfo *from)
3504 struct compat_siginfo new;
3506 copy_siginfo_to_external32(&new, from);
3507 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3512 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3513 const struct compat_siginfo *from)
3516 to->si_signo = from->si_signo;
3517 to->si_errno = from->si_errno;
3518 to->si_code = from->si_code;
3519 switch(siginfo_layout(from->si_signo, from->si_code)) {
3521 to->si_pid = from->si_pid;
3522 to->si_uid = from->si_uid;
3525 to->si_tid = from->si_tid;
3526 to->si_overrun = from->si_overrun;
3527 to->si_int = from->si_int;
3530 to->si_band = from->si_band;
3531 to->si_fd = from->si_fd;
3534 to->si_addr = compat_ptr(from->si_addr);
3536 case SIL_FAULT_TRAPNO:
3537 to->si_addr = compat_ptr(from->si_addr);
3538 to->si_trapno = from->si_trapno;
3540 case SIL_FAULT_MCEERR:
3541 to->si_addr = compat_ptr(from->si_addr);
3542 to->si_addr_lsb = from->si_addr_lsb;
3544 case SIL_FAULT_BNDERR:
3545 to->si_addr = compat_ptr(from->si_addr);
3546 to->si_lower = compat_ptr(from->si_lower);
3547 to->si_upper = compat_ptr(from->si_upper);
3549 case SIL_FAULT_PKUERR:
3550 to->si_addr = compat_ptr(from->si_addr);
3551 to->si_pkey = from->si_pkey;
3553 case SIL_FAULT_PERF_EVENT:
3554 to->si_addr = compat_ptr(from->si_addr);
3555 to->si_perf_data = from->si_perf_data;
3556 to->si_perf_type = from->si_perf_type;
3557 to->si_perf_flags = from->si_perf_flags;
3560 to->si_pid = from->si_pid;
3561 to->si_uid = from->si_uid;
3562 to->si_status = from->si_status;
3563 #ifdef CONFIG_X86_X32_ABI
3564 if (in_x32_syscall()) {
3565 to->si_utime = from->_sifields._sigchld_x32._utime;
3566 to->si_stime = from->_sifields._sigchld_x32._stime;
3570 to->si_utime = from->si_utime;
3571 to->si_stime = from->si_stime;
3575 to->si_pid = from->si_pid;
3576 to->si_uid = from->si_uid;
3577 to->si_int = from->si_int;
3580 to->si_call_addr = compat_ptr(from->si_call_addr);
3581 to->si_syscall = from->si_syscall;
3582 to->si_arch = from->si_arch;
3588 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3589 const struct compat_siginfo __user *ufrom)
3591 struct compat_siginfo from;
3593 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3596 from.si_signo = signo;
3597 return post_copy_siginfo_from_user32(to, &from);
3600 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3601 const struct compat_siginfo __user *ufrom)
3603 struct compat_siginfo from;
3605 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3608 return post_copy_siginfo_from_user32(to, &from);
3610 #endif /* CONFIG_COMPAT */
3613 * do_sigtimedwait - wait for queued signals specified in @which
3614 * @which: queued signals to wait for
3615 * @info: if non-null, the signal's siginfo is returned here
3616 * @ts: upper bound on process time suspension
3618 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3619 const struct timespec64 *ts)
3621 ktime_t *to = NULL, timeout = KTIME_MAX;
3622 struct task_struct *tsk = current;
3623 sigset_t mask = *which;
3627 if (!timespec64_valid(ts))
3629 timeout = timespec64_to_ktime(*ts);
3634 * Invert the set of allowed signals to get those we want to block.
3636 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3639 spin_lock_irq(&tsk->sighand->siglock);
3640 sig = dequeue_signal(tsk, &mask, info);
3641 if (!sig && timeout) {
3643 * None ready, temporarily unblock those we're interested
3644 * while we are sleeping in so that we'll be awakened when
3645 * they arrive. Unblocking is always fine, we can avoid
3646 * set_current_blocked().
3648 tsk->real_blocked = tsk->blocked;
3649 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3650 recalc_sigpending();
3651 spin_unlock_irq(&tsk->sighand->siglock);
3653 __set_current_state(TASK_INTERRUPTIBLE);
3654 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3656 spin_lock_irq(&tsk->sighand->siglock);
3657 __set_task_blocked(tsk, &tsk->real_blocked);
3658 sigemptyset(&tsk->real_blocked);
3659 sig = dequeue_signal(tsk, &mask, info);
3661 spin_unlock_irq(&tsk->sighand->siglock);
3665 return ret ? -EINTR : -EAGAIN;
3669 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3671 * @uthese: queued signals to wait for
3672 * @uinfo: if non-null, the signal's siginfo is returned here
3673 * @uts: upper bound on process time suspension
3674 * @sigsetsize: size of sigset_t type
3676 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3677 siginfo_t __user *, uinfo,
3678 const struct __kernel_timespec __user *, uts,
3682 struct timespec64 ts;
3683 kernel_siginfo_t info;
3686 /* XXX: Don't preclude handling different sized sigset_t's. */
3687 if (sigsetsize != sizeof(sigset_t))
3690 if (copy_from_user(&these, uthese, sizeof(these)))
3694 if (get_timespec64(&ts, uts))
3698 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3700 if (ret > 0 && uinfo) {
3701 if (copy_siginfo_to_user(uinfo, &info))
3708 #ifdef CONFIG_COMPAT_32BIT_TIME
3709 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3710 siginfo_t __user *, uinfo,
3711 const struct old_timespec32 __user *, uts,
3715 struct timespec64 ts;
3716 kernel_siginfo_t info;
3719 if (sigsetsize != sizeof(sigset_t))
3722 if (copy_from_user(&these, uthese, sizeof(these)))
3726 if (get_old_timespec32(&ts, uts))
3730 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3732 if (ret > 0 && uinfo) {
3733 if (copy_siginfo_to_user(uinfo, &info))
3741 #ifdef CONFIG_COMPAT
3742 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3743 struct compat_siginfo __user *, uinfo,
3744 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3747 struct timespec64 t;
3748 kernel_siginfo_t info;
3751 if (sigsetsize != sizeof(sigset_t))
3754 if (get_compat_sigset(&s, uthese))
3758 if (get_timespec64(&t, uts))
3762 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3764 if (ret > 0 && uinfo) {
3765 if (copy_siginfo_to_user32(uinfo, &info))
3772 #ifdef CONFIG_COMPAT_32BIT_TIME
3773 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3774 struct compat_siginfo __user *, uinfo,
3775 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3778 struct timespec64 t;
3779 kernel_siginfo_t info;
3782 if (sigsetsize != sizeof(sigset_t))
3785 if (get_compat_sigset(&s, uthese))
3789 if (get_old_timespec32(&t, uts))
3793 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3795 if (ret > 0 && uinfo) {
3796 if (copy_siginfo_to_user32(uinfo, &info))
3805 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3807 clear_siginfo(info);
3808 info->si_signo = sig;
3810 info->si_code = SI_USER;
3811 info->si_pid = task_tgid_vnr(current);
3812 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3816 * sys_kill - send a signal to a process
3817 * @pid: the PID of the process
3818 * @sig: signal to be sent
3820 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3822 struct kernel_siginfo info;
3824 prepare_kill_siginfo(sig, &info);
3826 return kill_something_info(sig, &info, pid);
3830 * Verify that the signaler and signalee either are in the same pid namespace
3831 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3834 static bool access_pidfd_pidns(struct pid *pid)
3836 struct pid_namespace *active = task_active_pid_ns(current);
3837 struct pid_namespace *p = ns_of_pid(pid);
3850 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
3851 siginfo_t __user *info)
3853 #ifdef CONFIG_COMPAT
3855 * Avoid hooking up compat syscalls and instead handle necessary
3856 * conversions here. Note, this is a stop-gap measure and should not be
3857 * considered a generic solution.
3859 if (in_compat_syscall())
3860 return copy_siginfo_from_user32(
3861 kinfo, (struct compat_siginfo __user *)info);
3863 return copy_siginfo_from_user(kinfo, info);
3866 static struct pid *pidfd_to_pid(const struct file *file)
3870 pid = pidfd_pid(file);
3874 return tgid_pidfd_to_pid(file);
3878 * sys_pidfd_send_signal - Signal a process through a pidfd
3879 * @pidfd: file descriptor of the process
3880 * @sig: signal to send
3881 * @info: signal info
3882 * @flags: future flags
3884 * The syscall currently only signals via PIDTYPE_PID which covers
3885 * kill(<positive-pid>, <signal>. It does not signal threads or process
3887 * In order to extend the syscall to threads and process groups the @flags
3888 * argument should be used. In essence, the @flags argument will determine
3889 * what is signaled and not the file descriptor itself. Put in other words,
3890 * grouping is a property of the flags argument not a property of the file
3893 * Return: 0 on success, negative errno on failure
3895 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3896 siginfo_t __user *, info, unsigned int, flags)
3901 kernel_siginfo_t kinfo;
3903 /* Enforce flags be set to 0 until we add an extension. */
3911 /* Is this a pidfd? */
3912 pid = pidfd_to_pid(f.file);
3919 if (!access_pidfd_pidns(pid))
3923 ret = copy_siginfo_from_user_any(&kinfo, info);
3928 if (unlikely(sig != kinfo.si_signo))
3931 /* Only allow sending arbitrary signals to yourself. */
3933 if ((task_pid(current) != pid) &&
3934 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3937 prepare_kill_siginfo(sig, &kinfo);
3940 ret = kill_pid_info(sig, &kinfo, pid);
3948 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3950 struct task_struct *p;
3954 p = find_task_by_vpid(pid);
3955 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3956 error = check_kill_permission(sig, info, p);
3958 * The null signal is a permissions and process existence
3959 * probe. No signal is actually delivered.
3961 if (!error && sig) {
3962 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3964 * If lock_task_sighand() failed we pretend the task
3965 * dies after receiving the signal. The window is tiny,
3966 * and the signal is private anyway.
3968 if (unlikely(error == -ESRCH))
3977 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3979 struct kernel_siginfo info;
3981 clear_siginfo(&info);
3982 info.si_signo = sig;
3984 info.si_code = SI_TKILL;
3985 info.si_pid = task_tgid_vnr(current);
3986 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3988 return do_send_specific(tgid, pid, sig, &info);
3992 * sys_tgkill - send signal to one specific thread
3993 * @tgid: the thread group ID of the thread
3994 * @pid: the PID of the thread
3995 * @sig: signal to be sent
3997 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3998 * exists but it's not belonging to the target process anymore. This
3999 * method solves the problem of threads exiting and PIDs getting reused.
4001 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
4003 /* This is only valid for single tasks */
4004 if (pid <= 0 || tgid <= 0)
4007 return do_tkill(tgid, pid, sig);
4011 * sys_tkill - send signal to one specific task
4012 * @pid: the PID of the task
4013 * @sig: signal to be sent
4015 * Send a signal to only one task, even if it's a CLONE_THREAD task.
4017 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
4019 /* This is only valid for single tasks */
4023 return do_tkill(0, pid, sig);
4026 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
4028 /* Not even root can pretend to send signals from the kernel.
4029 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4031 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4032 (task_pid_vnr(current) != pid))
4035 /* POSIX.1b doesn't mention process groups. */
4036 return kill_proc_info(sig, info, pid);
4040 * sys_rt_sigqueueinfo - send signal information to a signal
4041 * @pid: the PID of the thread
4042 * @sig: signal to be sent
4043 * @uinfo: signal info to be sent
4045 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
4046 siginfo_t __user *, uinfo)
4048 kernel_siginfo_t info;
4049 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4052 return do_rt_sigqueueinfo(pid, sig, &info);
4055 #ifdef CONFIG_COMPAT
4056 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
4059 struct compat_siginfo __user *, uinfo)
4061 kernel_siginfo_t info;
4062 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4065 return do_rt_sigqueueinfo(pid, sig, &info);
4069 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
4071 /* This is only valid for single tasks */
4072 if (pid <= 0 || tgid <= 0)
4075 /* Not even root can pretend to send signals from the kernel.
4076 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4078 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4079 (task_pid_vnr(current) != pid))
4082 return do_send_specific(tgid, pid, sig, info);
4085 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
4086 siginfo_t __user *, uinfo)
4088 kernel_siginfo_t info;
4089 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4092 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4095 #ifdef CONFIG_COMPAT
4096 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
4100 struct compat_siginfo __user *, uinfo)
4102 kernel_siginfo_t info;
4103 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4106 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4111 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
4113 void kernel_sigaction(int sig, __sighandler_t action)
4115 spin_lock_irq(¤t->sighand->siglock);
4116 current->sighand->action[sig - 1].sa.sa_handler = action;
4117 if (action == SIG_IGN) {
4121 sigaddset(&mask, sig);
4123 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
4124 flush_sigqueue_mask(&mask, ¤t->pending);
4125 recalc_sigpending();
4127 spin_unlock_irq(¤t->sighand->siglock);
4129 EXPORT_SYMBOL(kernel_sigaction);
4131 void __weak sigaction_compat_abi(struct k_sigaction *act,
4132 struct k_sigaction *oact)
4136 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
4138 struct task_struct *p = current, *t;
4139 struct k_sigaction *k;
4142 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
4145 k = &p->sighand->action[sig-1];
4147 spin_lock_irq(&p->sighand->siglock);
4148 if (k->sa.sa_flags & SA_IMMUTABLE) {
4149 spin_unlock_irq(&p->sighand->siglock);
4156 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
4157 * e.g. by having an architecture use the bit in their uapi.
4159 BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
4162 * Clear unknown flag bits in order to allow userspace to detect missing
4163 * support for flag bits and to allow the kernel to use non-uapi bits
4167 act->sa.sa_flags &= UAPI_SA_FLAGS;
4169 oact->sa.sa_flags &= UAPI_SA_FLAGS;
4171 sigaction_compat_abi(act, oact);
4174 sigdelsetmask(&act->sa.sa_mask,
4175 sigmask(SIGKILL) | sigmask(SIGSTOP));
4179 * "Setting a signal action to SIG_IGN for a signal that is
4180 * pending shall cause the pending signal to be discarded,
4181 * whether or not it is blocked."
4183 * "Setting a signal action to SIG_DFL for a signal that is
4184 * pending and whose default action is to ignore the signal
4185 * (for example, SIGCHLD), shall cause the pending signal to
4186 * be discarded, whether or not it is blocked"
4188 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
4190 sigaddset(&mask, sig);
4191 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
4192 for_each_thread(p, t)
4193 flush_sigqueue_mask(&mask, &t->pending);
4197 spin_unlock_irq(&p->sighand->siglock);
4202 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4205 struct task_struct *t = current;
4208 memset(oss, 0, sizeof(stack_t));
4209 oss->ss_sp = (void __user *) t->sas_ss_sp;
4210 oss->ss_size = t->sas_ss_size;
4211 oss->ss_flags = sas_ss_flags(sp) |
4212 (current->sas_ss_flags & SS_FLAG_BITS);
4216 void __user *ss_sp = ss->ss_sp;
4217 size_t ss_size = ss->ss_size;
4218 unsigned ss_flags = ss->ss_flags;
4221 if (unlikely(on_sig_stack(sp)))
4224 ss_mode = ss_flags & ~SS_FLAG_BITS;
4225 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4229 if (ss_mode == SS_DISABLE) {
4233 if (unlikely(ss_size < min_ss_size))
4237 t->sas_ss_sp = (unsigned long) ss_sp;
4238 t->sas_ss_size = ss_size;
4239 t->sas_ss_flags = ss_flags;
4244 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4248 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4250 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4251 current_user_stack_pointer(),
4253 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4258 int restore_altstack(const stack_t __user *uss)
4261 if (copy_from_user(&new, uss, sizeof(stack_t)))
4263 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4265 /* squash all but EFAULT for now */
4269 int __save_altstack(stack_t __user *uss, unsigned long sp)
4271 struct task_struct *t = current;
4272 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4273 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4274 __put_user(t->sas_ss_size, &uss->ss_size);
4278 #ifdef CONFIG_COMPAT
4279 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4280 compat_stack_t __user *uoss_ptr)
4286 compat_stack_t uss32;
4287 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4289 uss.ss_sp = compat_ptr(uss32.ss_sp);
4290 uss.ss_flags = uss32.ss_flags;
4291 uss.ss_size = uss32.ss_size;
4293 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4294 compat_user_stack_pointer(),
4295 COMPAT_MINSIGSTKSZ);
4296 if (ret >= 0 && uoss_ptr) {
4298 memset(&old, 0, sizeof(old));
4299 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4300 old.ss_flags = uoss.ss_flags;
4301 old.ss_size = uoss.ss_size;
4302 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4308 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4309 const compat_stack_t __user *, uss_ptr,
4310 compat_stack_t __user *, uoss_ptr)
4312 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4315 int compat_restore_altstack(const compat_stack_t __user *uss)
4317 int err = do_compat_sigaltstack(uss, NULL);
4318 /* squash all but -EFAULT for now */
4319 return err == -EFAULT ? err : 0;
4322 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4325 struct task_struct *t = current;
4326 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4328 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4329 __put_user(t->sas_ss_size, &uss->ss_size);
4334 #ifdef __ARCH_WANT_SYS_SIGPENDING
4337 * sys_sigpending - examine pending signals
4338 * @uset: where mask of pending signal is returned
4340 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4344 if (sizeof(old_sigset_t) > sizeof(*uset))
4347 do_sigpending(&set);
4349 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4355 #ifdef CONFIG_COMPAT
4356 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4360 do_sigpending(&set);
4362 return put_user(set.sig[0], set32);
4368 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4370 * sys_sigprocmask - examine and change blocked signals
4371 * @how: whether to add, remove, or set signals
4372 * @nset: signals to add or remove (if non-null)
4373 * @oset: previous value of signal mask if non-null
4375 * Some platforms have their own version with special arguments;
4376 * others support only sys_rt_sigprocmask.
4379 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4380 old_sigset_t __user *, oset)
4382 old_sigset_t old_set, new_set;
4383 sigset_t new_blocked;
4385 old_set = current->blocked.sig[0];
4388 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4391 new_blocked = current->blocked;
4395 sigaddsetmask(&new_blocked, new_set);
4398 sigdelsetmask(&new_blocked, new_set);
4401 new_blocked.sig[0] = new_set;
4407 set_current_blocked(&new_blocked);
4411 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4417 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4419 #ifndef CONFIG_ODD_RT_SIGACTION
4421 * sys_rt_sigaction - alter an action taken by a process
4422 * @sig: signal to be sent
4423 * @act: new sigaction
4424 * @oact: used to save the previous sigaction
4425 * @sigsetsize: size of sigset_t type
4427 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4428 const struct sigaction __user *, act,
4429 struct sigaction __user *, oact,
4432 struct k_sigaction new_sa, old_sa;
4435 /* XXX: Don't preclude handling different sized sigset_t's. */
4436 if (sigsetsize != sizeof(sigset_t))
4439 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4442 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4446 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4451 #ifdef CONFIG_COMPAT
4452 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4453 const struct compat_sigaction __user *, act,
4454 struct compat_sigaction __user *, oact,
4455 compat_size_t, sigsetsize)
4457 struct k_sigaction new_ka, old_ka;
4458 #ifdef __ARCH_HAS_SA_RESTORER
4459 compat_uptr_t restorer;
4463 /* XXX: Don't preclude handling different sized sigset_t's. */
4464 if (sigsetsize != sizeof(compat_sigset_t))
4468 compat_uptr_t handler;
4469 ret = get_user(handler, &act->sa_handler);
4470 new_ka.sa.sa_handler = compat_ptr(handler);
4471 #ifdef __ARCH_HAS_SA_RESTORER
4472 ret |= get_user(restorer, &act->sa_restorer);
4473 new_ka.sa.sa_restorer = compat_ptr(restorer);
4475 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4476 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4481 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4483 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4485 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4486 sizeof(oact->sa_mask));
4487 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4488 #ifdef __ARCH_HAS_SA_RESTORER
4489 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4490 &oact->sa_restorer);
4496 #endif /* !CONFIG_ODD_RT_SIGACTION */
4498 #ifdef CONFIG_OLD_SIGACTION
4499 SYSCALL_DEFINE3(sigaction, int, sig,
4500 const struct old_sigaction __user *, act,
4501 struct old_sigaction __user *, oact)
4503 struct k_sigaction new_ka, old_ka;
4508 if (!access_ok(act, sizeof(*act)) ||
4509 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4510 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4511 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4512 __get_user(mask, &act->sa_mask))
4514 #ifdef __ARCH_HAS_KA_RESTORER
4515 new_ka.ka_restorer = NULL;
4517 siginitset(&new_ka.sa.sa_mask, mask);
4520 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4523 if (!access_ok(oact, sizeof(*oact)) ||
4524 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4525 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4526 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4527 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4534 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4535 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4536 const struct compat_old_sigaction __user *, act,
4537 struct compat_old_sigaction __user *, oact)
4539 struct k_sigaction new_ka, old_ka;
4541 compat_old_sigset_t mask;
4542 compat_uptr_t handler, restorer;
4545 if (!access_ok(act, sizeof(*act)) ||
4546 __get_user(handler, &act->sa_handler) ||
4547 __get_user(restorer, &act->sa_restorer) ||
4548 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4549 __get_user(mask, &act->sa_mask))
4552 #ifdef __ARCH_HAS_KA_RESTORER
4553 new_ka.ka_restorer = NULL;
4555 new_ka.sa.sa_handler = compat_ptr(handler);
4556 new_ka.sa.sa_restorer = compat_ptr(restorer);
4557 siginitset(&new_ka.sa.sa_mask, mask);
4560 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4563 if (!access_ok(oact, sizeof(*oact)) ||
4564 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4565 &oact->sa_handler) ||
4566 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4567 &oact->sa_restorer) ||
4568 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4569 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4576 #ifdef CONFIG_SGETMASK_SYSCALL
4579 * For backwards compatibility. Functionality superseded by sigprocmask.
4581 SYSCALL_DEFINE0(sgetmask)
4584 return current->blocked.sig[0];
4587 SYSCALL_DEFINE1(ssetmask, int, newmask)
4589 int old = current->blocked.sig[0];
4592 siginitset(&newset, newmask);
4593 set_current_blocked(&newset);
4597 #endif /* CONFIG_SGETMASK_SYSCALL */
4599 #ifdef __ARCH_WANT_SYS_SIGNAL
4601 * For backwards compatibility. Functionality superseded by sigaction.
4603 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4605 struct k_sigaction new_sa, old_sa;
4608 new_sa.sa.sa_handler = handler;
4609 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4610 sigemptyset(&new_sa.sa.sa_mask);
4612 ret = do_sigaction(sig, &new_sa, &old_sa);
4614 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4616 #endif /* __ARCH_WANT_SYS_SIGNAL */
4618 #ifdef __ARCH_WANT_SYS_PAUSE
4620 SYSCALL_DEFINE0(pause)
4622 while (!signal_pending(current)) {
4623 __set_current_state(TASK_INTERRUPTIBLE);
4626 return -ERESTARTNOHAND;
4631 static int sigsuspend(sigset_t *set)
4633 current->saved_sigmask = current->blocked;
4634 set_current_blocked(set);
4636 while (!signal_pending(current)) {
4637 __set_current_state(TASK_INTERRUPTIBLE);
4640 set_restore_sigmask();
4641 return -ERESTARTNOHAND;
4645 * sys_rt_sigsuspend - replace the signal mask for a value with the
4646 * @unewset value until a signal is received
4647 * @unewset: new signal mask value
4648 * @sigsetsize: size of sigset_t type
4650 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4654 /* XXX: Don't preclude handling different sized sigset_t's. */
4655 if (sigsetsize != sizeof(sigset_t))
4658 if (copy_from_user(&newset, unewset, sizeof(newset)))
4660 return sigsuspend(&newset);
4663 #ifdef CONFIG_COMPAT
4664 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4668 /* XXX: Don't preclude handling different sized sigset_t's. */
4669 if (sigsetsize != sizeof(sigset_t))
4672 if (get_compat_sigset(&newset, unewset))
4674 return sigsuspend(&newset);
4678 #ifdef CONFIG_OLD_SIGSUSPEND
4679 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4682 siginitset(&blocked, mask);
4683 return sigsuspend(&blocked);
4686 #ifdef CONFIG_OLD_SIGSUSPEND3
4687 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4690 siginitset(&blocked, mask);
4691 return sigsuspend(&blocked);
4695 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4700 static inline void siginfo_buildtime_checks(void)
4702 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4704 /* Verify the offsets in the two siginfos match */
4705 #define CHECK_OFFSET(field) \
4706 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4709 CHECK_OFFSET(si_pid);
4710 CHECK_OFFSET(si_uid);
4713 CHECK_OFFSET(si_tid);
4714 CHECK_OFFSET(si_overrun);
4715 CHECK_OFFSET(si_value);
4718 CHECK_OFFSET(si_pid);
4719 CHECK_OFFSET(si_uid);
4720 CHECK_OFFSET(si_value);
4723 CHECK_OFFSET(si_pid);
4724 CHECK_OFFSET(si_uid);
4725 CHECK_OFFSET(si_status);
4726 CHECK_OFFSET(si_utime);
4727 CHECK_OFFSET(si_stime);
4730 CHECK_OFFSET(si_addr);
4731 CHECK_OFFSET(si_trapno);
4732 CHECK_OFFSET(si_addr_lsb);
4733 CHECK_OFFSET(si_lower);
4734 CHECK_OFFSET(si_upper);
4735 CHECK_OFFSET(si_pkey);
4736 CHECK_OFFSET(si_perf_data);
4737 CHECK_OFFSET(si_perf_type);
4738 CHECK_OFFSET(si_perf_flags);
4741 CHECK_OFFSET(si_band);
4742 CHECK_OFFSET(si_fd);
4745 CHECK_OFFSET(si_call_addr);
4746 CHECK_OFFSET(si_syscall);
4747 CHECK_OFFSET(si_arch);
4751 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4752 offsetof(struct siginfo, si_addr));
4753 if (sizeof(int) == sizeof(void __user *)) {
4754 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4755 sizeof(void __user *));
4757 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4758 sizeof_field(struct siginfo, si_uid)) !=
4759 sizeof(void __user *));
4760 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4761 offsetof(struct siginfo, si_uid));
4763 #ifdef CONFIG_COMPAT
4764 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4765 offsetof(struct compat_siginfo, si_addr));
4766 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4767 sizeof(compat_uptr_t));
4768 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4769 sizeof_field(struct siginfo, si_pid));
4773 void __init signals_init(void)
4775 siginfo_buildtime_checks();
4777 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT);
4780 #ifdef CONFIG_KGDB_KDB
4781 #include <linux/kdb.h>
4783 * kdb_send_sig - Allows kdb to send signals without exposing
4784 * signal internals. This function checks if the required locks are
4785 * available before calling the main signal code, to avoid kdb
4788 void kdb_send_sig(struct task_struct *t, int sig)
4790 static struct task_struct *kdb_prev_t;
4792 if (!spin_trylock(&t->sighand->siglock)) {
4793 kdb_printf("Can't do kill command now.\n"
4794 "The sigmask lock is held somewhere else in "
4795 "kernel, try again later\n");
4798 new_t = kdb_prev_t != t;
4800 if (!task_is_running(t) && new_t) {
4801 spin_unlock(&t->sighand->siglock);
4802 kdb_printf("Process is not RUNNING, sending a signal from "
4803 "kdb risks deadlock\n"
4804 "on the run queue locks. "
4805 "The signal has _not_ been sent.\n"
4806 "Reissue the kill command if you want to risk "
4810 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4811 spin_unlock(&t->sighand->siglock);
4813 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4816 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4818 #endif /* CONFIG_KGDB_KDB */