1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
9 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
10 * Changes to use preallocated sigqueue structures
11 * to allow signals to be sent reliably.
14 #include <linux/slab.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/debug.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/sched/cputime.h>
23 #include <linux/file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/tty.h>
27 #include <linux/binfmts.h>
28 #include <linux/coredump.h>
29 #include <linux/security.h>
30 #include <linux/syscalls.h>
31 #include <linux/ptrace.h>
32 #include <linux/signal.h>
33 #include <linux/signalfd.h>
34 #include <linux/ratelimit.h>
35 #include <linux/task_work.h>
36 #include <linux/capability.h>
37 #include <linux/freezer.h>
38 #include <linux/pid_namespace.h>
39 #include <linux/nsproxy.h>
40 #include <linux/user_namespace.h>
41 #include <linux/uprobes.h>
42 #include <linux/compat.h>
43 #include <linux/cn_proc.h>
44 #include <linux/compiler.h>
45 #include <linux/posix-timers.h>
46 #include <linux/cgroup.h>
47 #include <linux/audit.h>
49 #define CREATE_TRACE_POINTS
50 #include <trace/events/signal.h>
52 #include <asm/param.h>
53 #include <linux/uaccess.h>
54 #include <asm/unistd.h>
55 #include <asm/siginfo.h>
56 #include <asm/cacheflush.h>
57 #include <asm/syscall.h> /* for syscall_get_* */
60 * SLAB caches for signal bits.
63 static struct kmem_cache *sigqueue_cachep;
65 int print_fatal_signals __read_mostly;
67 static void __user *sig_handler(struct task_struct *t, int sig)
69 return t->sighand->action[sig - 1].sa.sa_handler;
72 static inline bool sig_handler_ignored(void __user *handler, int sig)
74 /* Is it explicitly or implicitly ignored? */
75 return handler == SIG_IGN ||
76 (handler == SIG_DFL && sig_kernel_ignore(sig));
79 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
83 handler = sig_handler(t, sig);
85 /* SIGKILL and SIGSTOP may not be sent to the global init */
86 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
89 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
90 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
93 /* Only allow kernel generated signals to this kthread */
94 if (unlikely((t->flags & PF_KTHREAD) &&
95 (handler == SIG_KTHREAD_KERNEL) && !force))
98 return sig_handler_ignored(handler, sig);
101 static bool sig_ignored(struct task_struct *t, int sig, bool force)
104 * Blocked signals are never ignored, since the
105 * signal handler may change by the time it is
108 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
112 * Tracers may want to know about even ignored signal unless it
113 * is SIGKILL which can't be reported anyway but can be ignored
114 * by SIGNAL_UNKILLABLE task.
116 if (t->ptrace && sig != SIGKILL)
119 return sig_task_ignored(t, sig, force);
123 * Re-calculate pending state from the set of locally pending
124 * signals, globally pending signals, and blocked signals.
126 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
131 switch (_NSIG_WORDS) {
133 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
134 ready |= signal->sig[i] &~ blocked->sig[i];
137 case 4: ready = signal->sig[3] &~ blocked->sig[3];
138 ready |= signal->sig[2] &~ blocked->sig[2];
139 ready |= signal->sig[1] &~ blocked->sig[1];
140 ready |= signal->sig[0] &~ blocked->sig[0];
143 case 2: ready = signal->sig[1] &~ blocked->sig[1];
144 ready |= signal->sig[0] &~ blocked->sig[0];
147 case 1: ready = signal->sig[0] &~ blocked->sig[0];
152 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
154 static bool recalc_sigpending_tsk(struct task_struct *t)
156 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
157 PENDING(&t->pending, &t->blocked) ||
158 PENDING(&t->signal->shared_pending, &t->blocked) ||
159 cgroup_task_frozen(t)) {
160 set_tsk_thread_flag(t, TIF_SIGPENDING);
165 * We must never clear the flag in another thread, or in current
166 * when it's possible the current syscall is returning -ERESTART*.
167 * So we don't clear it here, and only callers who know they should do.
173 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
174 * This is superfluous when called on current, the wakeup is a harmless no-op.
176 void recalc_sigpending_and_wake(struct task_struct *t)
178 if (recalc_sigpending_tsk(t))
179 signal_wake_up(t, 0);
182 void recalc_sigpending(void)
184 if (!recalc_sigpending_tsk(current) && !freezing(current))
185 clear_thread_flag(TIF_SIGPENDING);
188 EXPORT_SYMBOL(recalc_sigpending);
190 void calculate_sigpending(void)
192 /* Have any signals or users of TIF_SIGPENDING been delayed
195 spin_lock_irq(¤t->sighand->siglock);
196 set_tsk_thread_flag(current, TIF_SIGPENDING);
198 spin_unlock_irq(¤t->sighand->siglock);
201 /* Given the mask, find the first available signal that should be serviced. */
203 #define SYNCHRONOUS_MASK \
204 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
205 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
207 int next_signal(struct sigpending *pending, sigset_t *mask)
209 unsigned long i, *s, *m, x;
212 s = pending->signal.sig;
216 * Handle the first word specially: it contains the
217 * synchronous signals that need to be dequeued first.
221 if (x & SYNCHRONOUS_MASK)
222 x &= SYNCHRONOUS_MASK;
227 switch (_NSIG_WORDS) {
229 for (i = 1; i < _NSIG_WORDS; ++i) {
233 sig = ffz(~x) + i*_NSIG_BPW + 1;
242 sig = ffz(~x) + _NSIG_BPW + 1;
253 static inline void print_dropped_signal(int sig)
255 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
257 if (!print_fatal_signals)
260 if (!__ratelimit(&ratelimit_state))
263 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
264 current->comm, current->pid, sig);
268 * task_set_jobctl_pending - set jobctl pending bits
270 * @mask: pending bits to set
272 * Clear @mask from @task->jobctl. @mask must be subset of
273 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
274 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
275 * cleared. If @task is already being killed or exiting, this function
279 * Must be called with @task->sighand->siglock held.
282 * %true if @mask is set, %false if made noop because @task was dying.
284 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
286 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
287 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
288 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
290 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
293 if (mask & JOBCTL_STOP_SIGMASK)
294 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
296 task->jobctl |= mask;
301 * task_clear_jobctl_trapping - clear jobctl trapping bit
304 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
305 * Clear it and wake up the ptracer. Note that we don't need any further
306 * locking. @task->siglock guarantees that @task->parent points to the
310 * Must be called with @task->sighand->siglock held.
312 void task_clear_jobctl_trapping(struct task_struct *task)
314 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
315 task->jobctl &= ~JOBCTL_TRAPPING;
316 smp_mb(); /* advised by wake_up_bit() */
317 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
322 * task_clear_jobctl_pending - clear jobctl pending bits
324 * @mask: pending bits to clear
326 * Clear @mask from @task->jobctl. @mask must be subset of
327 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
328 * STOP bits are cleared together.
330 * If clearing of @mask leaves no stop or trap pending, this function calls
331 * task_clear_jobctl_trapping().
334 * Must be called with @task->sighand->siglock held.
336 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
338 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
340 if (mask & JOBCTL_STOP_PENDING)
341 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
343 task->jobctl &= ~mask;
345 if (!(task->jobctl & JOBCTL_PENDING_MASK))
346 task_clear_jobctl_trapping(task);
350 * task_participate_group_stop - participate in a group stop
351 * @task: task participating in a group stop
353 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
354 * Group stop states are cleared and the group stop count is consumed if
355 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
356 * stop, the appropriate `SIGNAL_*` flags are set.
359 * Must be called with @task->sighand->siglock held.
362 * %true if group stop completion should be notified to the parent, %false
365 static bool task_participate_group_stop(struct task_struct *task)
367 struct signal_struct *sig = task->signal;
368 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
370 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
372 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
377 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
378 sig->group_stop_count--;
381 * Tell the caller to notify completion iff we are entering into a
382 * fresh group stop. Read comment in do_signal_stop() for details.
384 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
385 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
391 void task_join_group_stop(struct task_struct *task)
393 unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
394 struct signal_struct *sig = current->signal;
396 if (sig->group_stop_count) {
397 sig->group_stop_count++;
398 mask |= JOBCTL_STOP_CONSUME;
399 } else if (!(sig->flags & SIGNAL_STOP_STOPPED))
402 /* Have the new thread join an on-going signal group stop */
403 task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
407 * allocate a new signal queue record
408 * - this may be called without locks if and only if t == current, otherwise an
409 * appropriate lock must be held to stop the target task from exiting
411 static struct sigqueue *
412 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
413 int override_rlimit, const unsigned int sigqueue_flags)
415 struct sigqueue *q = NULL;
416 struct ucounts *ucounts = NULL;
420 * Protect access to @t credentials. This can go away when all
421 * callers hold rcu read lock.
423 * NOTE! A pending signal will hold on to the user refcount,
424 * and we get/put the refcount only when the sigpending count
425 * changes from/to zero.
428 ucounts = task_ucounts(t);
429 sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
434 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
435 q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
437 print_dropped_signal(sig);
440 if (unlikely(q == NULL)) {
441 dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
443 INIT_LIST_HEAD(&q->list);
444 q->flags = sigqueue_flags;
445 q->ucounts = ucounts;
450 static void __sigqueue_free(struct sigqueue *q)
452 if (q->flags & SIGQUEUE_PREALLOC)
455 dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING);
458 kmem_cache_free(sigqueue_cachep, q);
461 void flush_sigqueue(struct sigpending *queue)
465 sigemptyset(&queue->signal);
466 while (!list_empty(&queue->list)) {
467 q = list_entry(queue->list.next, struct sigqueue , list);
468 list_del_init(&q->list);
474 * Flush all pending signals for this kthread.
476 void flush_signals(struct task_struct *t)
480 spin_lock_irqsave(&t->sighand->siglock, flags);
481 clear_tsk_thread_flag(t, TIF_SIGPENDING);
482 flush_sigqueue(&t->pending);
483 flush_sigqueue(&t->signal->shared_pending);
484 spin_unlock_irqrestore(&t->sighand->siglock, flags);
486 EXPORT_SYMBOL(flush_signals);
488 #ifdef CONFIG_POSIX_TIMERS
489 static void __flush_itimer_signals(struct sigpending *pending)
491 sigset_t signal, retain;
492 struct sigqueue *q, *n;
494 signal = pending->signal;
495 sigemptyset(&retain);
497 list_for_each_entry_safe(q, n, &pending->list, list) {
498 int sig = q->info.si_signo;
500 if (likely(q->info.si_code != SI_TIMER)) {
501 sigaddset(&retain, sig);
503 sigdelset(&signal, sig);
504 list_del_init(&q->list);
509 sigorsets(&pending->signal, &signal, &retain);
512 void flush_itimer_signals(void)
514 struct task_struct *tsk = current;
517 spin_lock_irqsave(&tsk->sighand->siglock, flags);
518 __flush_itimer_signals(&tsk->pending);
519 __flush_itimer_signals(&tsk->signal->shared_pending);
520 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
524 void ignore_signals(struct task_struct *t)
528 for (i = 0; i < _NSIG; ++i)
529 t->sighand->action[i].sa.sa_handler = SIG_IGN;
535 * Flush all handlers for a task.
539 flush_signal_handlers(struct task_struct *t, int force_default)
542 struct k_sigaction *ka = &t->sighand->action[0];
543 for (i = _NSIG ; i != 0 ; i--) {
544 if (force_default || ka->sa.sa_handler != SIG_IGN)
545 ka->sa.sa_handler = SIG_DFL;
547 #ifdef __ARCH_HAS_SA_RESTORER
548 ka->sa.sa_restorer = NULL;
550 sigemptyset(&ka->sa.sa_mask);
555 bool unhandled_signal(struct task_struct *tsk, int sig)
557 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
558 if (is_global_init(tsk))
561 if (handler != SIG_IGN && handler != SIG_DFL)
564 /* if ptraced, let the tracer determine */
568 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
571 struct sigqueue *q, *first = NULL;
574 * Collect the siginfo appropriate to this signal. Check if
575 * there is another siginfo for the same signal.
577 list_for_each_entry(q, &list->list, list) {
578 if (q->info.si_signo == sig) {
585 sigdelset(&list->signal, sig);
589 list_del_init(&first->list);
590 copy_siginfo(info, &first->info);
593 (first->flags & SIGQUEUE_PREALLOC) &&
594 (info->si_code == SI_TIMER) &&
595 (info->si_sys_private);
597 __sigqueue_free(first);
600 * Ok, it wasn't in the queue. This must be
601 * a fast-pathed signal or we must have been
602 * out of queue space. So zero out the info.
605 info->si_signo = sig;
607 info->si_code = SI_USER;
613 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
614 kernel_siginfo_t *info, bool *resched_timer)
616 int sig = next_signal(pending, mask);
619 collect_signal(sig, pending, info, resched_timer);
624 * Dequeue a signal and return the element to the caller, which is
625 * expected to free it.
627 * All callers have to hold the siglock.
629 int dequeue_signal(struct task_struct *tsk, sigset_t *mask,
630 kernel_siginfo_t *info, enum pid_type *type)
632 bool resched_timer = false;
635 /* We only dequeue private signals from ourselves, we don't let
636 * signalfd steal them
639 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
641 *type = PIDTYPE_TGID;
642 signr = __dequeue_signal(&tsk->signal->shared_pending,
643 mask, info, &resched_timer);
644 #ifdef CONFIG_POSIX_TIMERS
648 * itimers are process shared and we restart periodic
649 * itimers in the signal delivery path to prevent DoS
650 * attacks in the high resolution timer case. This is
651 * compliant with the old way of self-restarting
652 * itimers, as the SIGALRM is a legacy signal and only
653 * queued once. Changing the restart behaviour to
654 * restart the timer in the signal dequeue path is
655 * reducing the timer noise on heavy loaded !highres
658 if (unlikely(signr == SIGALRM)) {
659 struct hrtimer *tmr = &tsk->signal->real_timer;
661 if (!hrtimer_is_queued(tmr) &&
662 tsk->signal->it_real_incr != 0) {
663 hrtimer_forward(tmr, tmr->base->get_time(),
664 tsk->signal->it_real_incr);
665 hrtimer_restart(tmr);
675 if (unlikely(sig_kernel_stop(signr))) {
677 * Set a marker that we have dequeued a stop signal. Our
678 * caller might release the siglock and then the pending
679 * stop signal it is about to process is no longer in the
680 * pending bitmasks, but must still be cleared by a SIGCONT
681 * (and overruled by a SIGKILL). So those cases clear this
682 * shared flag after we've set it. Note that this flag may
683 * remain set after the signal we return is ignored or
684 * handled. That doesn't matter because its only purpose
685 * is to alert stop-signal processing code when another
686 * processor has come along and cleared the flag.
688 current->jobctl |= JOBCTL_STOP_DEQUEUED;
690 #ifdef CONFIG_POSIX_TIMERS
693 * Release the siglock to ensure proper locking order
694 * of timer locks outside of siglocks. Note, we leave
695 * irqs disabled here, since the posix-timers code is
696 * about to disable them again anyway.
698 spin_unlock(&tsk->sighand->siglock);
699 posixtimer_rearm(info);
700 spin_lock(&tsk->sighand->siglock);
702 /* Don't expose the si_sys_private value to userspace */
703 info->si_sys_private = 0;
708 EXPORT_SYMBOL_GPL(dequeue_signal);
710 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
712 struct task_struct *tsk = current;
713 struct sigpending *pending = &tsk->pending;
714 struct sigqueue *q, *sync = NULL;
717 * Might a synchronous signal be in the queue?
719 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
723 * Return the first synchronous signal in the queue.
725 list_for_each_entry(q, &pending->list, list) {
726 /* Synchronous signals have a positive si_code */
727 if ((q->info.si_code > SI_USER) &&
728 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
736 * Check if there is another siginfo for the same signal.
738 list_for_each_entry_continue(q, &pending->list, list) {
739 if (q->info.si_signo == sync->info.si_signo)
743 sigdelset(&pending->signal, sync->info.si_signo);
746 list_del_init(&sync->list);
747 copy_siginfo(info, &sync->info);
748 __sigqueue_free(sync);
749 return info->si_signo;
753 * Tell a process that it has a new active signal..
755 * NOTE! we rely on the previous spin_lock to
756 * lock interrupts for us! We can only be called with
757 * "siglock" held, and the local interrupt must
758 * have been disabled when that got acquired!
760 * No need to set need_resched since signal event passing
761 * goes through ->blocked
763 void signal_wake_up_state(struct task_struct *t, unsigned int state)
765 lockdep_assert_held(&t->sighand->siglock);
767 set_tsk_thread_flag(t, TIF_SIGPENDING);
770 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
771 * case. We don't check t->state here because there is a race with it
772 * executing another processor and just now entering stopped state.
773 * By using wake_up_state, we ensure the process will wake up and
774 * handle its death signal.
776 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
781 * Remove signals in mask from the pending set and queue.
782 * Returns 1 if any signals were found.
784 * All callers must be holding the siglock.
786 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
788 struct sigqueue *q, *n;
791 sigandsets(&m, mask, &s->signal);
792 if (sigisemptyset(&m))
795 sigandnsets(&s->signal, &s->signal, mask);
796 list_for_each_entry_safe(q, n, &s->list, list) {
797 if (sigismember(mask, q->info.si_signo)) {
798 list_del_init(&q->list);
804 static inline int is_si_special(const struct kernel_siginfo *info)
806 return info <= SEND_SIG_PRIV;
809 static inline bool si_fromuser(const struct kernel_siginfo *info)
811 return info == SEND_SIG_NOINFO ||
812 (!is_si_special(info) && SI_FROMUSER(info));
816 * called with RCU read lock from check_kill_permission()
818 static bool kill_ok_by_cred(struct task_struct *t)
820 const struct cred *cred = current_cred();
821 const struct cred *tcred = __task_cred(t);
823 return uid_eq(cred->euid, tcred->suid) ||
824 uid_eq(cred->euid, tcred->uid) ||
825 uid_eq(cred->uid, tcred->suid) ||
826 uid_eq(cred->uid, tcred->uid) ||
827 ns_capable(tcred->user_ns, CAP_KILL);
831 * Bad permissions for sending the signal
832 * - the caller must hold the RCU read lock
834 static int check_kill_permission(int sig, struct kernel_siginfo *info,
835 struct task_struct *t)
840 if (!valid_signal(sig))
843 if (!si_fromuser(info))
846 error = audit_signal_info(sig, t); /* Let audit system see the signal */
850 if (!same_thread_group(current, t) &&
851 !kill_ok_by_cred(t)) {
854 sid = task_session(t);
856 * We don't return the error if sid == NULL. The
857 * task was unhashed, the caller must notice this.
859 if (!sid || sid == task_session(current))
867 return security_task_kill(t, info, sig, NULL);
871 * ptrace_trap_notify - schedule trap to notify ptracer
872 * @t: tracee wanting to notify tracer
874 * This function schedules sticky ptrace trap which is cleared on the next
875 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
878 * If @t is running, STOP trap will be taken. If trapped for STOP and
879 * ptracer is listening for events, tracee is woken up so that it can
880 * re-trap for the new event. If trapped otherwise, STOP trap will be
881 * eventually taken without returning to userland after the existing traps
882 * are finished by PTRACE_CONT.
885 * Must be called with @task->sighand->siglock held.
887 static void ptrace_trap_notify(struct task_struct *t)
889 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
890 lockdep_assert_held(&t->sighand->siglock);
892 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
893 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
897 * Handle magic process-wide effects of stop/continue signals. Unlike
898 * the signal actions, these happen immediately at signal-generation
899 * time regardless of blocking, ignoring, or handling. This does the
900 * actual continuing for SIGCONT, but not the actual stopping for stop
901 * signals. The process stop is done as a signal action for SIG_DFL.
903 * Returns true if the signal should be actually delivered, otherwise
904 * it should be dropped.
906 static bool prepare_signal(int sig, struct task_struct *p, bool force)
908 struct signal_struct *signal = p->signal;
909 struct task_struct *t;
912 if (signal->flags & SIGNAL_GROUP_EXIT) {
913 if (signal->core_state)
914 return sig == SIGKILL;
916 * The process is in the middle of dying, drop the signal.
919 } else if (sig_kernel_stop(sig)) {
921 * This is a stop signal. Remove SIGCONT from all queues.
923 siginitset(&flush, sigmask(SIGCONT));
924 flush_sigqueue_mask(&flush, &signal->shared_pending);
925 for_each_thread(p, t)
926 flush_sigqueue_mask(&flush, &t->pending);
927 } else if (sig == SIGCONT) {
930 * Remove all stop signals from all queues, wake all threads.
932 siginitset(&flush, SIG_KERNEL_STOP_MASK);
933 flush_sigqueue_mask(&flush, &signal->shared_pending);
934 for_each_thread(p, t) {
935 flush_sigqueue_mask(&flush, &t->pending);
936 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
937 if (likely(!(t->ptrace & PT_SEIZED))) {
938 t->jobctl &= ~JOBCTL_STOPPED;
939 wake_up_state(t, __TASK_STOPPED);
941 ptrace_trap_notify(t);
945 * Notify the parent with CLD_CONTINUED if we were stopped.
947 * If we were in the middle of a group stop, we pretend it
948 * was already finished, and then continued. Since SIGCHLD
949 * doesn't queue we report only CLD_STOPPED, as if the next
950 * CLD_CONTINUED was dropped.
953 if (signal->flags & SIGNAL_STOP_STOPPED)
954 why |= SIGNAL_CLD_CONTINUED;
955 else if (signal->group_stop_count)
956 why |= SIGNAL_CLD_STOPPED;
960 * The first thread which returns from do_signal_stop()
961 * will take ->siglock, notice SIGNAL_CLD_MASK, and
962 * notify its parent. See get_signal().
964 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
965 signal->group_stop_count = 0;
966 signal->group_exit_code = 0;
970 return !sig_ignored(p, sig, force);
974 * Test if P wants to take SIG. After we've checked all threads with this,
975 * it's equivalent to finding no threads not blocking SIG. Any threads not
976 * blocking SIG were ruled out because they are not running and already
977 * have pending signals. Such threads will dequeue from the shared queue
978 * as soon as they're available, so putting the signal on the shared queue
979 * will be equivalent to sending it to one such thread.
981 static inline bool wants_signal(int sig, struct task_struct *p)
983 if (sigismember(&p->blocked, sig))
986 if (p->flags & PF_EXITING)
992 if (task_is_stopped_or_traced(p))
995 return task_curr(p) || !task_sigpending(p);
998 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
1000 struct signal_struct *signal = p->signal;
1001 struct task_struct *t;
1004 * Now find a thread we can wake up to take the signal off the queue.
1006 * Try the suggested task first (may or may not be the main thread).
1008 if (wants_signal(sig, p))
1010 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1012 * There is just one thread and it does not need to be woken.
1013 * It will dequeue unblocked signals before it runs again.
1018 * Otherwise try to find a suitable thread.
1020 t = signal->curr_target;
1021 while (!wants_signal(sig, t)) {
1023 if (t == signal->curr_target)
1025 * No thread needs to be woken.
1026 * Any eligible threads will see
1027 * the signal in the queue soon.
1031 signal->curr_target = t;
1035 * Found a killable thread. If the signal will be fatal,
1036 * then start taking the whole group down immediately.
1038 if (sig_fatal(p, sig) &&
1039 (signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) &&
1040 !sigismember(&t->real_blocked, sig) &&
1041 (sig == SIGKILL || !p->ptrace)) {
1043 * This signal will be fatal to the whole group.
1045 if (!sig_kernel_coredump(sig)) {
1047 * Start a group exit and wake everybody up.
1048 * This way we don't have other threads
1049 * running and doing things after a slower
1050 * thread has the fatal signal pending.
1052 signal->flags = SIGNAL_GROUP_EXIT;
1053 signal->group_exit_code = sig;
1054 signal->group_stop_count = 0;
1057 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1058 sigaddset(&t->pending.signal, SIGKILL);
1059 signal_wake_up(t, 1);
1060 } while_each_thread(p, t);
1066 * The signal is already in the shared-pending queue.
1067 * Tell the chosen thread to wake up and dequeue it.
1069 signal_wake_up(t, sig == SIGKILL);
1073 static inline bool legacy_queue(struct sigpending *signals, int sig)
1075 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1078 static int __send_signal_locked(int sig, struct kernel_siginfo *info,
1079 struct task_struct *t, enum pid_type type, bool force)
1081 struct sigpending *pending;
1083 int override_rlimit;
1084 int ret = 0, result;
1086 lockdep_assert_held(&t->sighand->siglock);
1088 result = TRACE_SIGNAL_IGNORED;
1089 if (!prepare_signal(sig, t, force))
1092 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1094 * Short-circuit ignored signals and support queuing
1095 * exactly one non-rt signal, so that we can get more
1096 * detailed information about the cause of the signal.
1098 result = TRACE_SIGNAL_ALREADY_PENDING;
1099 if (legacy_queue(pending, sig))
1102 result = TRACE_SIGNAL_DELIVERED;
1104 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1106 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1110 * Real-time signals must be queued if sent by sigqueue, or
1111 * some other real-time mechanism. It is implementation
1112 * defined whether kill() does so. We attempt to do so, on
1113 * the principle of least surprise, but since kill is not
1114 * allowed to fail with EAGAIN when low on memory we just
1115 * make sure at least one signal gets delivered and don't
1116 * pass on the info struct.
1119 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1121 override_rlimit = 0;
1123 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
1126 list_add_tail(&q->list, &pending->list);
1127 switch ((unsigned long) info) {
1128 case (unsigned long) SEND_SIG_NOINFO:
1129 clear_siginfo(&q->info);
1130 q->info.si_signo = sig;
1131 q->info.si_errno = 0;
1132 q->info.si_code = SI_USER;
1133 q->info.si_pid = task_tgid_nr_ns(current,
1134 task_active_pid_ns(t));
1137 from_kuid_munged(task_cred_xxx(t, user_ns),
1141 case (unsigned long) SEND_SIG_PRIV:
1142 clear_siginfo(&q->info);
1143 q->info.si_signo = sig;
1144 q->info.si_errno = 0;
1145 q->info.si_code = SI_KERNEL;
1150 copy_siginfo(&q->info, info);
1153 } else if (!is_si_special(info) &&
1154 sig >= SIGRTMIN && info->si_code != SI_USER) {
1156 * Queue overflow, abort. We may abort if the
1157 * signal was rt and sent by user using something
1158 * other than kill().
1160 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1165 * This is a silent loss of information. We still
1166 * send the signal, but the *info bits are lost.
1168 result = TRACE_SIGNAL_LOSE_INFO;
1172 signalfd_notify(t, sig);
1173 sigaddset(&pending->signal, sig);
1175 /* Let multiprocess signals appear after on-going forks */
1176 if (type > PIDTYPE_TGID) {
1177 struct multiprocess_signals *delayed;
1178 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1179 sigset_t *signal = &delayed->signal;
1180 /* Can't queue both a stop and a continue signal */
1182 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1183 else if (sig_kernel_stop(sig))
1184 sigdelset(signal, SIGCONT);
1185 sigaddset(signal, sig);
1189 complete_signal(sig, t, type);
1191 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1195 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1198 switch (siginfo_layout(info->si_signo, info->si_code)) {
1207 case SIL_FAULT_TRAPNO:
1208 case SIL_FAULT_MCEERR:
1209 case SIL_FAULT_BNDERR:
1210 case SIL_FAULT_PKUERR:
1211 case SIL_FAULT_PERF_EVENT:
1219 int send_signal_locked(int sig, struct kernel_siginfo *info,
1220 struct task_struct *t, enum pid_type type)
1222 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1225 if (info == SEND_SIG_NOINFO) {
1226 /* Force if sent from an ancestor pid namespace */
1227 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1228 } else if (info == SEND_SIG_PRIV) {
1229 /* Don't ignore kernel generated signals */
1231 } else if (has_si_pid_and_uid(info)) {
1232 /* SIGKILL and SIGSTOP is special or has ids */
1233 struct user_namespace *t_user_ns;
1236 t_user_ns = task_cred_xxx(t, user_ns);
1237 if (current_user_ns() != t_user_ns) {
1238 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1239 info->si_uid = from_kuid_munged(t_user_ns, uid);
1243 /* A kernel generated signal? */
1244 force = (info->si_code == SI_KERNEL);
1246 /* From an ancestor pid namespace? */
1247 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1252 return __send_signal_locked(sig, info, t, type, force);
1255 static void print_fatal_signal(int signr)
1257 struct pt_regs *regs = task_pt_regs(current);
1258 pr_info("potentially unexpected fatal signal %d.\n", signr);
1260 #if defined(__i386__) && !defined(__arch_um__)
1261 pr_info("code at %08lx: ", regs->ip);
1264 for (i = 0; i < 16; i++) {
1267 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1269 pr_cont("%02x ", insn);
1279 static int __init setup_print_fatal_signals(char *str)
1281 get_option (&str, &print_fatal_signals);
1286 __setup("print-fatal-signals=", setup_print_fatal_signals);
1288 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1291 unsigned long flags;
1294 if (lock_task_sighand(p, &flags)) {
1295 ret = send_signal_locked(sig, info, p, type);
1296 unlock_task_sighand(p, &flags);
1303 HANDLER_CURRENT, /* If reachable use the current handler */
1304 HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */
1305 HANDLER_EXIT, /* Only visible as the process exit code */
1309 * Force a signal that the process can't ignore: if necessary
1310 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1312 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1313 * since we do not want to have a signal handler that was blocked
1314 * be invoked when user space had explicitly blocked it.
1316 * We don't want to have recursive SIGSEGV's etc, for example,
1317 * that is why we also clear SIGNAL_UNKILLABLE.
1320 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
1321 enum sig_handler handler)
1323 unsigned long int flags;
1324 int ret, blocked, ignored;
1325 struct k_sigaction *action;
1326 int sig = info->si_signo;
1328 spin_lock_irqsave(&t->sighand->siglock, flags);
1329 action = &t->sighand->action[sig-1];
1330 ignored = action->sa.sa_handler == SIG_IGN;
1331 blocked = sigismember(&t->blocked, sig);
1332 if (blocked || ignored || (handler != HANDLER_CURRENT)) {
1333 action->sa.sa_handler = SIG_DFL;
1334 if (handler == HANDLER_EXIT)
1335 action->sa.sa_flags |= SA_IMMUTABLE;
1337 sigdelset(&t->blocked, sig);
1338 recalc_sigpending_and_wake(t);
1342 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1343 * debugging to leave init killable. But HANDLER_EXIT is always fatal.
1345 if (action->sa.sa_handler == SIG_DFL &&
1346 (!t->ptrace || (handler == HANDLER_EXIT)))
1347 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1348 ret = send_signal_locked(sig, info, t, PIDTYPE_PID);
1349 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1354 int force_sig_info(struct kernel_siginfo *info)
1356 return force_sig_info_to_task(info, current, HANDLER_CURRENT);
1360 * Nuke all other threads in the group.
1362 int zap_other_threads(struct task_struct *p)
1364 struct task_struct *t = p;
1367 p->signal->group_stop_count = 0;
1369 while_each_thread(p, t) {
1370 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1371 /* Don't require de_thread to wait for the vhost_worker */
1372 if ((t->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)
1375 /* Don't bother with already dead threads */
1378 sigaddset(&t->pending.signal, SIGKILL);
1379 signal_wake_up(t, 1);
1385 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1386 unsigned long *flags)
1388 struct sighand_struct *sighand;
1392 sighand = rcu_dereference(tsk->sighand);
1393 if (unlikely(sighand == NULL))
1397 * This sighand can be already freed and even reused, but
1398 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1399 * initializes ->siglock: this slab can't go away, it has
1400 * the same object type, ->siglock can't be reinitialized.
1402 * We need to ensure that tsk->sighand is still the same
1403 * after we take the lock, we can race with de_thread() or
1404 * __exit_signal(). In the latter case the next iteration
1405 * must see ->sighand == NULL.
1407 spin_lock_irqsave(&sighand->siglock, *flags);
1408 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1410 spin_unlock_irqrestore(&sighand->siglock, *flags);
1417 #ifdef CONFIG_LOCKDEP
1418 void lockdep_assert_task_sighand_held(struct task_struct *task)
1420 struct sighand_struct *sighand;
1423 sighand = rcu_dereference(task->sighand);
1425 lockdep_assert_held(&sighand->siglock);
1433 * send signal info to all the members of a group
1435 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1436 struct task_struct *p, enum pid_type type)
1441 ret = check_kill_permission(sig, info, p);
1445 ret = do_send_sig_info(sig, info, p, type);
1451 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1452 * control characters do (^C, ^Z etc)
1453 * - the caller must hold at least a readlock on tasklist_lock
1455 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1457 struct task_struct *p = NULL;
1458 int retval, success;
1462 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1463 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1466 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1467 return success ? 0 : retval;
1470 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1473 struct task_struct *p;
1477 p = pid_task(pid, PIDTYPE_PID);
1479 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1481 if (likely(!p || error != -ESRCH))
1485 * The task was unhashed in between, try again. If it
1486 * is dead, pid_task() will return NULL, if we race with
1487 * de_thread() it will find the new leader.
1492 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1496 error = kill_pid_info(sig, info, find_vpid(pid));
1501 static inline bool kill_as_cred_perm(const struct cred *cred,
1502 struct task_struct *target)
1504 const struct cred *pcred = __task_cred(target);
1506 return uid_eq(cred->euid, pcred->suid) ||
1507 uid_eq(cred->euid, pcred->uid) ||
1508 uid_eq(cred->uid, pcred->suid) ||
1509 uid_eq(cred->uid, pcred->uid);
1513 * The usb asyncio usage of siginfo is wrong. The glibc support
1514 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1515 * AKA after the generic fields:
1516 * kernel_pid_t si_pid;
1517 * kernel_uid32_t si_uid;
1518 * sigval_t si_value;
1520 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1521 * after the generic fields is:
1522 * void __user *si_addr;
1524 * This is a practical problem when there is a 64bit big endian kernel
1525 * and a 32bit userspace. As the 32bit address will encoded in the low
1526 * 32bits of the pointer. Those low 32bits will be stored at higher
1527 * address than appear in a 32 bit pointer. So userspace will not
1528 * see the address it was expecting for it's completions.
1530 * There is nothing in the encoding that can allow
1531 * copy_siginfo_to_user32 to detect this confusion of formats, so
1532 * handle this by requiring the caller of kill_pid_usb_asyncio to
1533 * notice when this situration takes place and to store the 32bit
1534 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1537 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1538 struct pid *pid, const struct cred *cred)
1540 struct kernel_siginfo info;
1541 struct task_struct *p;
1542 unsigned long flags;
1545 if (!valid_signal(sig))
1548 clear_siginfo(&info);
1549 info.si_signo = sig;
1550 info.si_errno = errno;
1551 info.si_code = SI_ASYNCIO;
1552 *((sigval_t *)&info.si_pid) = addr;
1555 p = pid_task(pid, PIDTYPE_PID);
1560 if (!kill_as_cred_perm(cred, p)) {
1564 ret = security_task_kill(p, &info, sig, cred);
1569 if (lock_task_sighand(p, &flags)) {
1570 ret = __send_signal_locked(sig, &info, p, PIDTYPE_TGID, false);
1571 unlock_task_sighand(p, &flags);
1579 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1582 * kill_something_info() interprets pid in interesting ways just like kill(2).
1584 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1585 * is probably wrong. Should make it like BSD or SYSV.
1588 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1593 return kill_proc_info(sig, info, pid);
1595 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1599 read_lock(&tasklist_lock);
1601 ret = __kill_pgrp_info(sig, info,
1602 pid ? find_vpid(-pid) : task_pgrp(current));
1604 int retval = 0, count = 0;
1605 struct task_struct * p;
1607 for_each_process(p) {
1608 if (task_pid_vnr(p) > 1 &&
1609 !same_thread_group(p, current)) {
1610 int err = group_send_sig_info(sig, info, p,
1617 ret = count ? retval : -ESRCH;
1619 read_unlock(&tasklist_lock);
1625 * These are for backward compatibility with the rest of the kernel source.
1628 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1631 * Make sure legacy kernel users don't send in bad values
1632 * (normal paths check this in check_kill_permission).
1634 if (!valid_signal(sig))
1637 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1639 EXPORT_SYMBOL(send_sig_info);
1641 #define __si_special(priv) \
1642 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1645 send_sig(int sig, struct task_struct *p, int priv)
1647 return send_sig_info(sig, __si_special(priv), p);
1649 EXPORT_SYMBOL(send_sig);
1651 void force_sig(int sig)
1653 struct kernel_siginfo info;
1655 clear_siginfo(&info);
1656 info.si_signo = sig;
1658 info.si_code = SI_KERNEL;
1661 force_sig_info(&info);
1663 EXPORT_SYMBOL(force_sig);
1665 void force_fatal_sig(int sig)
1667 struct kernel_siginfo info;
1669 clear_siginfo(&info);
1670 info.si_signo = sig;
1672 info.si_code = SI_KERNEL;
1675 force_sig_info_to_task(&info, current, HANDLER_SIG_DFL);
1678 void force_exit_sig(int sig)
1680 struct kernel_siginfo info;
1682 clear_siginfo(&info);
1683 info.si_signo = sig;
1685 info.si_code = SI_KERNEL;
1688 force_sig_info_to_task(&info, current, HANDLER_EXIT);
1692 * When things go south during signal handling, we
1693 * will force a SIGSEGV. And if the signal that caused
1694 * the problem was already a SIGSEGV, we'll want to
1695 * make sure we don't even try to deliver the signal..
1697 void force_sigsegv(int sig)
1700 force_fatal_sig(SIGSEGV);
1705 int force_sig_fault_to_task(int sig, int code, void __user *addr
1706 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1707 , struct task_struct *t)
1709 struct kernel_siginfo info;
1711 clear_siginfo(&info);
1712 info.si_signo = sig;
1714 info.si_code = code;
1715 info.si_addr = addr;
1718 info.si_flags = flags;
1721 return force_sig_info_to_task(&info, t, HANDLER_CURRENT);
1724 int force_sig_fault(int sig, int code, void __user *addr
1725 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1727 return force_sig_fault_to_task(sig, code, addr
1728 ___ARCH_SI_IA64(imm, flags, isr), current);
1731 int send_sig_fault(int sig, int code, void __user *addr
1732 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1733 , struct task_struct *t)
1735 struct kernel_siginfo info;
1737 clear_siginfo(&info);
1738 info.si_signo = sig;
1740 info.si_code = code;
1741 info.si_addr = addr;
1744 info.si_flags = flags;
1747 return send_sig_info(info.si_signo, &info, t);
1750 int force_sig_mceerr(int code, void __user *addr, short lsb)
1752 struct kernel_siginfo info;
1754 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1755 clear_siginfo(&info);
1756 info.si_signo = SIGBUS;
1758 info.si_code = code;
1759 info.si_addr = addr;
1760 info.si_addr_lsb = lsb;
1761 return force_sig_info(&info);
1764 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1766 struct kernel_siginfo info;
1768 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1769 clear_siginfo(&info);
1770 info.si_signo = SIGBUS;
1772 info.si_code = code;
1773 info.si_addr = addr;
1774 info.si_addr_lsb = lsb;
1775 return send_sig_info(info.si_signo, &info, t);
1777 EXPORT_SYMBOL(send_sig_mceerr);
1779 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1781 struct kernel_siginfo info;
1783 clear_siginfo(&info);
1784 info.si_signo = SIGSEGV;
1786 info.si_code = SEGV_BNDERR;
1787 info.si_addr = addr;
1788 info.si_lower = lower;
1789 info.si_upper = upper;
1790 return force_sig_info(&info);
1794 int force_sig_pkuerr(void __user *addr, u32 pkey)
1796 struct kernel_siginfo info;
1798 clear_siginfo(&info);
1799 info.si_signo = SIGSEGV;
1801 info.si_code = SEGV_PKUERR;
1802 info.si_addr = addr;
1803 info.si_pkey = pkey;
1804 return force_sig_info(&info);
1808 int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
1810 struct kernel_siginfo info;
1812 clear_siginfo(&info);
1813 info.si_signo = SIGTRAP;
1815 info.si_code = TRAP_PERF;
1816 info.si_addr = addr;
1817 info.si_perf_data = sig_data;
1818 info.si_perf_type = type;
1821 * Signals generated by perf events should not terminate the whole
1822 * process if SIGTRAP is blocked, however, delivering the signal
1823 * asynchronously is better than not delivering at all. But tell user
1824 * space if the signal was asynchronous, so it can clearly be
1825 * distinguished from normal synchronous ones.
1827 info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ?
1828 TRAP_PERF_FLAG_ASYNC :
1831 return send_sig_info(info.si_signo, &info, current);
1835 * force_sig_seccomp - signals the task to allow in-process syscall emulation
1836 * @syscall: syscall number to send to userland
1837 * @reason: filter-supplied reason code to send to userland (via si_errno)
1838 * @force_coredump: true to trigger a coredump
1840 * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
1842 int force_sig_seccomp(int syscall, int reason, bool force_coredump)
1844 struct kernel_siginfo info;
1846 clear_siginfo(&info);
1847 info.si_signo = SIGSYS;
1848 info.si_code = SYS_SECCOMP;
1849 info.si_call_addr = (void __user *)KSTK_EIP(current);
1850 info.si_errno = reason;
1851 info.si_arch = syscall_get_arch(current);
1852 info.si_syscall = syscall;
1853 return force_sig_info_to_task(&info, current,
1854 force_coredump ? HANDLER_EXIT : HANDLER_CURRENT);
1857 /* For the crazy architectures that include trap information in
1858 * the errno field, instead of an actual errno value.
1860 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1862 struct kernel_siginfo info;
1864 clear_siginfo(&info);
1865 info.si_signo = SIGTRAP;
1866 info.si_errno = errno;
1867 info.si_code = TRAP_HWBKPT;
1868 info.si_addr = addr;
1869 return force_sig_info(&info);
1872 /* For the rare architectures that include trap information using
1875 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
1877 struct kernel_siginfo info;
1879 clear_siginfo(&info);
1880 info.si_signo = sig;
1882 info.si_code = code;
1883 info.si_addr = addr;
1884 info.si_trapno = trapno;
1885 return force_sig_info(&info);
1888 /* For the rare architectures that include trap information using
1891 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
1892 struct task_struct *t)
1894 struct kernel_siginfo info;
1896 clear_siginfo(&info);
1897 info.si_signo = sig;
1899 info.si_code = code;
1900 info.si_addr = addr;
1901 info.si_trapno = trapno;
1902 return send_sig_info(info.si_signo, &info, t);
1905 int kill_pgrp(struct pid *pid, int sig, int priv)
1909 read_lock(&tasklist_lock);
1910 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1911 read_unlock(&tasklist_lock);
1915 EXPORT_SYMBOL(kill_pgrp);
1917 int kill_pid(struct pid *pid, int sig, int priv)
1919 return kill_pid_info(sig, __si_special(priv), pid);
1921 EXPORT_SYMBOL(kill_pid);
1924 * These functions support sending signals using preallocated sigqueue
1925 * structures. This is needed "because realtime applications cannot
1926 * afford to lose notifications of asynchronous events, like timer
1927 * expirations or I/O completions". In the case of POSIX Timers
1928 * we allocate the sigqueue structure from the timer_create. If this
1929 * allocation fails we are able to report the failure to the application
1930 * with an EAGAIN error.
1932 struct sigqueue *sigqueue_alloc(void)
1934 return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
1937 void sigqueue_free(struct sigqueue *q)
1939 unsigned long flags;
1940 spinlock_t *lock = ¤t->sighand->siglock;
1942 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1944 * We must hold ->siglock while testing q->list
1945 * to serialize with collect_signal() or with
1946 * __exit_signal()->flush_sigqueue().
1948 spin_lock_irqsave(lock, flags);
1949 q->flags &= ~SIGQUEUE_PREALLOC;
1951 * If it is queued it will be freed when dequeued,
1952 * like the "regular" sigqueue.
1954 if (!list_empty(&q->list))
1956 spin_unlock_irqrestore(lock, flags);
1962 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1964 int sig = q->info.si_signo;
1965 struct sigpending *pending;
1966 struct task_struct *t;
1967 unsigned long flags;
1970 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1976 * This function is used by POSIX timers to deliver a timer signal.
1977 * Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID
1978 * set), the signal must be delivered to the specific thread (queues
1981 * Where type is not PIDTYPE_PID, signals must be delivered to the
1982 * process. In this case, prefer to deliver to current if it is in
1983 * the same thread group as the target process, which avoids
1984 * unnecessarily waking up a potentially idle task.
1986 t = pid_task(pid, type);
1989 if (type != PIDTYPE_PID && same_thread_group(t, current))
1991 if (!likely(lock_task_sighand(t, &flags)))
1994 ret = 1; /* the signal is ignored */
1995 result = TRACE_SIGNAL_IGNORED;
1996 if (!prepare_signal(sig, t, false))
2000 if (unlikely(!list_empty(&q->list))) {
2002 * If an SI_TIMER entry is already queue just increment
2003 * the overrun count.
2005 BUG_ON(q->info.si_code != SI_TIMER);
2006 q->info.si_overrun++;
2007 result = TRACE_SIGNAL_ALREADY_PENDING;
2010 q->info.si_overrun = 0;
2012 signalfd_notify(t, sig);
2013 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
2014 list_add_tail(&q->list, &pending->list);
2015 sigaddset(&pending->signal, sig);
2016 complete_signal(sig, t, type);
2017 result = TRACE_SIGNAL_DELIVERED;
2019 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
2020 unlock_task_sighand(t, &flags);
2026 static void do_notify_pidfd(struct task_struct *task)
2030 WARN_ON(task->exit_state == 0);
2031 pid = task_pid(task);
2032 wake_up_all(&pid->wait_pidfd);
2036 * Let a parent know about the death of a child.
2037 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
2039 * Returns true if our parent ignored us and so we've switched to
2042 bool do_notify_parent(struct task_struct *tsk, int sig)
2044 struct kernel_siginfo info;
2045 unsigned long flags;
2046 struct sighand_struct *psig;
2047 bool autoreap = false;
2050 WARN_ON_ONCE(sig == -1);
2052 /* do_notify_parent_cldstop should have been called instead. */
2053 WARN_ON_ONCE(task_is_stopped_or_traced(tsk));
2055 WARN_ON_ONCE(!tsk->ptrace &&
2056 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
2058 /* Wake up all pidfd waiters */
2059 do_notify_pidfd(tsk);
2061 if (sig != SIGCHLD) {
2063 * This is only possible if parent == real_parent.
2064 * Check if it has changed security domain.
2066 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
2070 clear_siginfo(&info);
2071 info.si_signo = sig;
2074 * We are under tasklist_lock here so our parent is tied to
2075 * us and cannot change.
2077 * task_active_pid_ns will always return the same pid namespace
2078 * until a task passes through release_task.
2080 * write_lock() currently calls preempt_disable() which is the
2081 * same as rcu_read_lock(), but according to Oleg, this is not
2082 * correct to rely on this
2085 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
2086 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
2090 task_cputime(tsk, &utime, &stime);
2091 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
2092 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
2094 info.si_status = tsk->exit_code & 0x7f;
2095 if (tsk->exit_code & 0x80)
2096 info.si_code = CLD_DUMPED;
2097 else if (tsk->exit_code & 0x7f)
2098 info.si_code = CLD_KILLED;
2100 info.si_code = CLD_EXITED;
2101 info.si_status = tsk->exit_code >> 8;
2104 psig = tsk->parent->sighand;
2105 spin_lock_irqsave(&psig->siglock, flags);
2106 if (!tsk->ptrace && sig == SIGCHLD &&
2107 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
2108 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
2110 * We are exiting and our parent doesn't care. POSIX.1
2111 * defines special semantics for setting SIGCHLD to SIG_IGN
2112 * or setting the SA_NOCLDWAIT flag: we should be reaped
2113 * automatically and not left for our parent's wait4 call.
2114 * Rather than having the parent do it as a magic kind of
2115 * signal handler, we just set this to tell do_exit that we
2116 * can be cleaned up without becoming a zombie. Note that
2117 * we still call __wake_up_parent in this case, because a
2118 * blocked sys_wait4 might now return -ECHILD.
2120 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
2121 * is implementation-defined: we do (if you don't want
2122 * it, just use SIG_IGN instead).
2125 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
2129 * Send with __send_signal as si_pid and si_uid are in the
2130 * parent's namespaces.
2132 if (valid_signal(sig) && sig)
2133 __send_signal_locked(sig, &info, tsk->parent, PIDTYPE_TGID, false);
2134 __wake_up_parent(tsk, tsk->parent);
2135 spin_unlock_irqrestore(&psig->siglock, flags);
2141 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2142 * @tsk: task reporting the state change
2143 * @for_ptracer: the notification is for ptracer
2144 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2146 * Notify @tsk's parent that the stopped/continued state has changed. If
2147 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2148 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2151 * Must be called with tasklist_lock at least read locked.
2153 static void do_notify_parent_cldstop(struct task_struct *tsk,
2154 bool for_ptracer, int why)
2156 struct kernel_siginfo info;
2157 unsigned long flags;
2158 struct task_struct *parent;
2159 struct sighand_struct *sighand;
2163 parent = tsk->parent;
2165 tsk = tsk->group_leader;
2166 parent = tsk->real_parent;
2169 clear_siginfo(&info);
2170 info.si_signo = SIGCHLD;
2173 * see comment in do_notify_parent() about the following 4 lines
2176 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2177 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2180 task_cputime(tsk, &utime, &stime);
2181 info.si_utime = nsec_to_clock_t(utime);
2182 info.si_stime = nsec_to_clock_t(stime);
2187 info.si_status = SIGCONT;
2190 info.si_status = tsk->signal->group_exit_code & 0x7f;
2193 info.si_status = tsk->exit_code & 0x7f;
2199 sighand = parent->sighand;
2200 spin_lock_irqsave(&sighand->siglock, flags);
2201 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2202 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2203 send_signal_locked(SIGCHLD, &info, parent, PIDTYPE_TGID);
2205 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2207 __wake_up_parent(tsk, parent);
2208 spin_unlock_irqrestore(&sighand->siglock, flags);
2212 * This must be called with current->sighand->siglock held.
2214 * This should be the path for all ptrace stops.
2215 * We always set current->last_siginfo while stopped here.
2216 * That makes it a way to test a stopped process for
2217 * being ptrace-stopped vs being job-control-stopped.
2219 * Returns the signal the ptracer requested the code resume
2220 * with. If the code did not stop because the tracer is gone,
2221 * the stop signal remains unchanged unless clear_code.
2223 static int ptrace_stop(int exit_code, int why, unsigned long message,
2224 kernel_siginfo_t *info)
2225 __releases(¤t->sighand->siglock)
2226 __acquires(¤t->sighand->siglock)
2228 bool gstop_done = false;
2230 if (arch_ptrace_stop_needed()) {
2232 * The arch code has something special to do before a
2233 * ptrace stop. This is allowed to block, e.g. for faults
2234 * on user stack pages. We can't keep the siglock while
2235 * calling arch_ptrace_stop, so we must release it now.
2236 * To preserve proper semantics, we must do this before
2237 * any signal bookkeeping like checking group_stop_count.
2239 spin_unlock_irq(¤t->sighand->siglock);
2241 spin_lock_irq(¤t->sighand->siglock);
2245 * After this point ptrace_signal_wake_up or signal_wake_up
2246 * will clear TASK_TRACED if ptrace_unlink happens or a fatal
2247 * signal comes in. Handle previous ptrace_unlinks and fatal
2248 * signals here to prevent ptrace_stop sleeping in schedule.
2250 if (!current->ptrace || __fatal_signal_pending(current))
2253 set_special_state(TASK_TRACED);
2254 current->jobctl |= JOBCTL_TRACED;
2257 * We're committing to trapping. TRACED should be visible before
2258 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2259 * Also, transition to TRACED and updates to ->jobctl should be
2260 * atomic with respect to siglock and should be done after the arch
2261 * hook as siglock is released and regrabbed across it.
2266 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2268 * set_current_state() smp_wmb();
2270 * wait_task_stopped()
2271 * task_stopped_code()
2272 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2276 current->ptrace_message = message;
2277 current->last_siginfo = info;
2278 current->exit_code = exit_code;
2281 * If @why is CLD_STOPPED, we're trapping to participate in a group
2282 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2283 * across siglock relocks since INTERRUPT was scheduled, PENDING
2284 * could be clear now. We act as if SIGCONT is received after
2285 * TASK_TRACED is entered - ignore it.
2287 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2288 gstop_done = task_participate_group_stop(current);
2290 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2291 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2292 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2293 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2295 /* entering a trap, clear TRAPPING */
2296 task_clear_jobctl_trapping(current);
2298 spin_unlock_irq(¤t->sighand->siglock);
2299 read_lock(&tasklist_lock);
2301 * Notify parents of the stop.
2303 * While ptraced, there are two parents - the ptracer and
2304 * the real_parent of the group_leader. The ptracer should
2305 * know about every stop while the real parent is only
2306 * interested in the completion of group stop. The states
2307 * for the two don't interact with each other. Notify
2308 * separately unless they're gonna be duplicates.
2310 if (current->ptrace)
2311 do_notify_parent_cldstop(current, true, why);
2312 if (gstop_done && (!current->ptrace || ptrace_reparented(current)))
2313 do_notify_parent_cldstop(current, false, why);
2316 * Don't want to allow preemption here, because
2317 * sys_ptrace() needs this task to be inactive.
2319 * XXX: implement read_unlock_no_resched().
2322 read_unlock(&tasklist_lock);
2323 cgroup_enter_frozen();
2324 preempt_enable_no_resched();
2326 cgroup_leave_frozen(true);
2329 * We are back. Now reacquire the siglock before touching
2330 * last_siginfo, so that we are sure to have synchronized with
2331 * any signal-sending on another CPU that wants to examine it.
2333 spin_lock_irq(¤t->sighand->siglock);
2334 exit_code = current->exit_code;
2335 current->last_siginfo = NULL;
2336 current->ptrace_message = 0;
2337 current->exit_code = 0;
2339 /* LISTENING can be set only during STOP traps, clear it */
2340 current->jobctl &= ~(JOBCTL_LISTENING | JOBCTL_PTRACE_FROZEN);
2343 * Queued signals ignored us while we were stopped for tracing.
2344 * So check for any that we should take before resuming user mode.
2345 * This sets TIF_SIGPENDING, but never clears it.
2347 recalc_sigpending_tsk(current);
2351 static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message)
2353 kernel_siginfo_t info;
2355 clear_siginfo(&info);
2356 info.si_signo = signr;
2357 info.si_code = exit_code;
2358 info.si_pid = task_pid_vnr(current);
2359 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2361 /* Let the debugger run. */
2362 return ptrace_stop(exit_code, why, message, &info);
2365 int ptrace_notify(int exit_code, unsigned long message)
2369 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2370 if (unlikely(task_work_pending(current)))
2373 spin_lock_irq(¤t->sighand->siglock);
2374 signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message);
2375 spin_unlock_irq(¤t->sighand->siglock);
2380 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2381 * @signr: signr causing group stop if initiating
2383 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2384 * and participate in it. If already set, participate in the existing
2385 * group stop. If participated in a group stop (and thus slept), %true is
2386 * returned with siglock released.
2388 * If ptraced, this function doesn't handle stop itself. Instead,
2389 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2390 * untouched. The caller must ensure that INTERRUPT trap handling takes
2391 * places afterwards.
2394 * Must be called with @current->sighand->siglock held, which is released
2398 * %false if group stop is already cancelled or ptrace trap is scheduled.
2399 * %true if participated in group stop.
2401 static bool do_signal_stop(int signr)
2402 __releases(¤t->sighand->siglock)
2404 struct signal_struct *sig = current->signal;
2406 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2407 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2408 struct task_struct *t;
2410 /* signr will be recorded in task->jobctl for retries */
2411 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2413 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2414 unlikely(sig->flags & SIGNAL_GROUP_EXIT) ||
2415 unlikely(sig->group_exec_task))
2418 * There is no group stop already in progress. We must
2421 * While ptraced, a task may be resumed while group stop is
2422 * still in effect and then receive a stop signal and
2423 * initiate another group stop. This deviates from the
2424 * usual behavior as two consecutive stop signals can't
2425 * cause two group stops when !ptraced. That is why we
2426 * also check !task_is_stopped(t) below.
2428 * The condition can be distinguished by testing whether
2429 * SIGNAL_STOP_STOPPED is already set. Don't generate
2430 * group_exit_code in such case.
2432 * This is not necessary for SIGNAL_STOP_CONTINUED because
2433 * an intervening stop signal is required to cause two
2434 * continued events regardless of ptrace.
2436 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2437 sig->group_exit_code = signr;
2439 sig->group_stop_count = 0;
2441 if (task_set_jobctl_pending(current, signr | gstop))
2442 sig->group_stop_count++;
2445 while_each_thread(current, t) {
2447 * Setting state to TASK_STOPPED for a group
2448 * stop is always done with the siglock held,
2449 * so this check has no races.
2451 if (!task_is_stopped(t) &&
2452 task_set_jobctl_pending(t, signr | gstop)) {
2453 sig->group_stop_count++;
2454 if (likely(!(t->ptrace & PT_SEIZED)))
2455 signal_wake_up(t, 0);
2457 ptrace_trap_notify(t);
2462 if (likely(!current->ptrace)) {
2466 * If there are no other threads in the group, or if there
2467 * is a group stop in progress and we are the last to stop,
2468 * report to the parent.
2470 if (task_participate_group_stop(current))
2471 notify = CLD_STOPPED;
2473 current->jobctl |= JOBCTL_STOPPED;
2474 set_special_state(TASK_STOPPED);
2475 spin_unlock_irq(¤t->sighand->siglock);
2478 * Notify the parent of the group stop completion. Because
2479 * we're not holding either the siglock or tasklist_lock
2480 * here, ptracer may attach inbetween; however, this is for
2481 * group stop and should always be delivered to the real
2482 * parent of the group leader. The new ptracer will get
2483 * its notification when this task transitions into
2487 read_lock(&tasklist_lock);
2488 do_notify_parent_cldstop(current, false, notify);
2489 read_unlock(&tasklist_lock);
2492 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2493 cgroup_enter_frozen();
2498 * While ptraced, group stop is handled by STOP trap.
2499 * Schedule it and let the caller deal with it.
2501 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2507 * do_jobctl_trap - take care of ptrace jobctl traps
2509 * When PT_SEIZED, it's used for both group stop and explicit
2510 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2511 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2512 * the stop signal; otherwise, %SIGTRAP.
2514 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2515 * number as exit_code and no siginfo.
2518 * Must be called with @current->sighand->siglock held, which may be
2519 * released and re-acquired before returning with intervening sleep.
2521 static void do_jobctl_trap(void)
2523 struct signal_struct *signal = current->signal;
2524 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2526 if (current->ptrace & PT_SEIZED) {
2527 if (!signal->group_stop_count &&
2528 !(signal->flags & SIGNAL_STOP_STOPPED))
2530 WARN_ON_ONCE(!signr);
2531 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2534 WARN_ON_ONCE(!signr);
2535 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2540 * do_freezer_trap - handle the freezer jobctl trap
2542 * Puts the task into frozen state, if only the task is not about to quit.
2543 * In this case it drops JOBCTL_TRAP_FREEZE.
2546 * Must be called with @current->sighand->siglock held,
2547 * which is always released before returning.
2549 static void do_freezer_trap(void)
2550 __releases(¤t->sighand->siglock)
2553 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2554 * let's make another loop to give it a chance to be handled.
2555 * In any case, we'll return back.
2557 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2558 JOBCTL_TRAP_FREEZE) {
2559 spin_unlock_irq(¤t->sighand->siglock);
2564 * Now we're sure that there is no pending fatal signal and no
2565 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2566 * immediately (if there is a non-fatal signal pending), and
2567 * put the task into sleep.
2569 __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
2570 clear_thread_flag(TIF_SIGPENDING);
2571 spin_unlock_irq(¤t->sighand->siglock);
2572 cgroup_enter_frozen();
2576 static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type)
2579 * We do not check sig_kernel_stop(signr) but set this marker
2580 * unconditionally because we do not know whether debugger will
2581 * change signr. This flag has no meaning unless we are going
2582 * to stop after return from ptrace_stop(). In this case it will
2583 * be checked in do_signal_stop(), we should only stop if it was
2584 * not cleared by SIGCONT while we were sleeping. See also the
2585 * comment in dequeue_signal().
2587 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2588 signr = ptrace_stop(signr, CLD_TRAPPED, 0, info);
2590 /* We're back. Did the debugger cancel the sig? */
2595 * Update the siginfo structure if the signal has
2596 * changed. If the debugger wanted something
2597 * specific in the siginfo structure then it should
2598 * have updated *info via PTRACE_SETSIGINFO.
2600 if (signr != info->si_signo) {
2601 clear_siginfo(info);
2602 info->si_signo = signr;
2604 info->si_code = SI_USER;
2606 info->si_pid = task_pid_vnr(current->parent);
2607 info->si_uid = from_kuid_munged(current_user_ns(),
2608 task_uid(current->parent));
2612 /* If the (new) signal is now blocked, requeue it. */
2613 if (sigismember(¤t->blocked, signr) ||
2614 fatal_signal_pending(current)) {
2615 send_signal_locked(signr, info, current, type);
2622 static void hide_si_addr_tag_bits(struct ksignal *ksig)
2624 switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
2626 case SIL_FAULT_TRAPNO:
2627 case SIL_FAULT_MCEERR:
2628 case SIL_FAULT_BNDERR:
2629 case SIL_FAULT_PKUERR:
2630 case SIL_FAULT_PERF_EVENT:
2631 ksig->info.si_addr = arch_untagged_si_addr(
2632 ksig->info.si_addr, ksig->sig, ksig->info.si_code);
2644 bool get_signal(struct ksignal *ksig)
2646 struct sighand_struct *sighand = current->sighand;
2647 struct signal_struct *signal = current->signal;
2650 clear_notify_signal();
2651 if (unlikely(task_work_pending(current)))
2654 if (!task_sigpending(current))
2657 if (unlikely(uprobe_deny_signal()))
2661 * Do this once, we can't return to user-mode if freezing() == T.
2662 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2663 * thus do not need another check after return.
2668 spin_lock_irq(&sighand->siglock);
2671 * Every stopped thread goes here after wakeup. Check to see if
2672 * we should notify the parent, prepare_signal(SIGCONT) encodes
2673 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2675 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2678 if (signal->flags & SIGNAL_CLD_CONTINUED)
2679 why = CLD_CONTINUED;
2683 signal->flags &= ~SIGNAL_CLD_MASK;
2685 spin_unlock_irq(&sighand->siglock);
2688 * Notify the parent that we're continuing. This event is
2689 * always per-process and doesn't make whole lot of sense
2690 * for ptracers, who shouldn't consume the state via
2691 * wait(2) either, but, for backward compatibility, notify
2692 * the ptracer of the group leader too unless it's gonna be
2695 read_lock(&tasklist_lock);
2696 do_notify_parent_cldstop(current, false, why);
2698 if (ptrace_reparented(current->group_leader))
2699 do_notify_parent_cldstop(current->group_leader,
2701 read_unlock(&tasklist_lock);
2707 struct k_sigaction *ka;
2710 /* Has this task already been marked for death? */
2711 if ((signal->flags & SIGNAL_GROUP_EXIT) ||
2712 signal->group_exec_task) {
2713 clear_siginfo(&ksig->info);
2714 ksig->info.si_signo = signr = SIGKILL;
2715 sigdelset(¤t->pending.signal, SIGKILL);
2716 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2717 &sighand->action[SIGKILL - 1]);
2718 recalc_sigpending();
2722 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2726 if (unlikely(current->jobctl &
2727 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2728 if (current->jobctl & JOBCTL_TRAP_MASK) {
2730 spin_unlock_irq(&sighand->siglock);
2731 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2738 * If the task is leaving the frozen state, let's update
2739 * cgroup counters and reset the frozen bit.
2741 if (unlikely(cgroup_task_frozen(current))) {
2742 spin_unlock_irq(&sighand->siglock);
2743 cgroup_leave_frozen(false);
2748 * Signals generated by the execution of an instruction
2749 * need to be delivered before any other pending signals
2750 * so that the instruction pointer in the signal stack
2751 * frame points to the faulting instruction.
2754 signr = dequeue_synchronous_signal(&ksig->info);
2756 signr = dequeue_signal(current, ¤t->blocked,
2757 &ksig->info, &type);
2760 break; /* will return 0 */
2762 if (unlikely(current->ptrace) && (signr != SIGKILL) &&
2763 !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) {
2764 signr = ptrace_signal(signr, &ksig->info, type);
2769 ka = &sighand->action[signr-1];
2771 /* Trace actually delivered signals. */
2772 trace_signal_deliver(signr, &ksig->info, ka);
2774 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2776 if (ka->sa.sa_handler != SIG_DFL) {
2777 /* Run the handler. */
2780 if (ka->sa.sa_flags & SA_ONESHOT)
2781 ka->sa.sa_handler = SIG_DFL;
2783 break; /* will return non-zero "signr" value */
2787 * Now we are doing the default action for this signal.
2789 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2793 * Global init gets no signals it doesn't want.
2794 * Container-init gets no signals it doesn't want from same
2797 * Note that if global/container-init sees a sig_kernel_only()
2798 * signal here, the signal must have been generated internally
2799 * or must have come from an ancestor namespace. In either
2800 * case, the signal cannot be dropped.
2802 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2803 !sig_kernel_only(signr))
2806 if (sig_kernel_stop(signr)) {
2808 * The default action is to stop all threads in
2809 * the thread group. The job control signals
2810 * do nothing in an orphaned pgrp, but SIGSTOP
2811 * always works. Note that siglock needs to be
2812 * dropped during the call to is_orphaned_pgrp()
2813 * because of lock ordering with tasklist_lock.
2814 * This allows an intervening SIGCONT to be posted.
2815 * We need to check for that and bail out if necessary.
2817 if (signr != SIGSTOP) {
2818 spin_unlock_irq(&sighand->siglock);
2820 /* signals can be posted during this window */
2822 if (is_current_pgrp_orphaned())
2825 spin_lock_irq(&sighand->siglock);
2828 if (likely(do_signal_stop(ksig->info.si_signo))) {
2829 /* It released the siglock. */
2834 * We didn't actually stop, due to a race
2835 * with SIGCONT or something like that.
2841 spin_unlock_irq(&sighand->siglock);
2842 if (unlikely(cgroup_task_frozen(current)))
2843 cgroup_leave_frozen(true);
2846 * Anything else is fatal, maybe with a core dump.
2848 current->flags |= PF_SIGNALED;
2850 if (sig_kernel_coredump(signr)) {
2851 if (print_fatal_signals)
2852 print_fatal_signal(ksig->info.si_signo);
2853 proc_coredump_connector(current);
2855 * If it was able to dump core, this kills all
2856 * other threads in the group and synchronizes with
2857 * their demise. If we lost the race with another
2858 * thread getting here, it set group_exit_code
2859 * first and our do_group_exit call below will use
2860 * that value and ignore the one we pass it.
2862 do_coredump(&ksig->info);
2866 * PF_USER_WORKER threads will catch and exit on fatal signals
2867 * themselves. They have cleanup that must be performed, so
2868 * we cannot call do_exit() on their behalf.
2870 if (current->flags & PF_USER_WORKER)
2874 * Death signals, no core dump.
2876 do_group_exit(ksig->info.si_signo);
2879 spin_unlock_irq(&sighand->siglock);
2883 if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
2884 hide_si_addr_tag_bits(ksig);
2886 return ksig->sig > 0;
2890 * signal_delivered - called after signal delivery to update blocked signals
2891 * @ksig: kernel signal struct
2892 * @stepping: nonzero if debugger single-step or block-step in use
2894 * This function should be called when a signal has successfully been
2895 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2896 * is always blocked), and the signal itself is blocked unless %SA_NODEFER
2897 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2899 static void signal_delivered(struct ksignal *ksig, int stepping)
2903 /* A signal was successfully delivered, and the
2904 saved sigmask was stored on the signal frame,
2905 and will be restored by sigreturn. So we can
2906 simply clear the restore sigmask flag. */
2907 clear_restore_sigmask();
2909 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2910 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2911 sigaddset(&blocked, ksig->sig);
2912 set_current_blocked(&blocked);
2913 if (current->sas_ss_flags & SS_AUTODISARM)
2914 sas_ss_reset(current);
2916 ptrace_notify(SIGTRAP, 0);
2919 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2922 force_sigsegv(ksig->sig);
2924 signal_delivered(ksig, stepping);
2928 * It could be that complete_signal() picked us to notify about the
2929 * group-wide signal. Other threads should be notified now to take
2930 * the shared signals in @which since we will not.
2932 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2935 struct task_struct *t;
2937 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2938 if (sigisemptyset(&retarget))
2942 while_each_thread(tsk, t) {
2943 if (t->flags & PF_EXITING)
2946 if (!has_pending_signals(&retarget, &t->blocked))
2948 /* Remove the signals this thread can handle. */
2949 sigandsets(&retarget, &retarget, &t->blocked);
2951 if (!task_sigpending(t))
2952 signal_wake_up(t, 0);
2954 if (sigisemptyset(&retarget))
2959 void exit_signals(struct task_struct *tsk)
2965 * @tsk is about to have PF_EXITING set - lock out users which
2966 * expect stable threadgroup.
2968 cgroup_threadgroup_change_begin(tsk);
2970 if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
2971 sched_mm_cid_exit_signals(tsk);
2972 tsk->flags |= PF_EXITING;
2973 cgroup_threadgroup_change_end(tsk);
2977 spin_lock_irq(&tsk->sighand->siglock);
2979 * From now this task is not visible for group-wide signals,
2980 * see wants_signal(), do_signal_stop().
2982 sched_mm_cid_exit_signals(tsk);
2983 tsk->flags |= PF_EXITING;
2985 cgroup_threadgroup_change_end(tsk);
2987 if (!task_sigpending(tsk))
2990 unblocked = tsk->blocked;
2991 signotset(&unblocked);
2992 retarget_shared_pending(tsk, &unblocked);
2994 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2995 task_participate_group_stop(tsk))
2996 group_stop = CLD_STOPPED;
2998 spin_unlock_irq(&tsk->sighand->siglock);
3001 * If group stop has completed, deliver the notification. This
3002 * should always go to the real parent of the group leader.
3004 if (unlikely(group_stop)) {
3005 read_lock(&tasklist_lock);
3006 do_notify_parent_cldstop(tsk, false, group_stop);
3007 read_unlock(&tasklist_lock);
3012 * System call entry points.
3016 * sys_restart_syscall - restart a system call
3018 SYSCALL_DEFINE0(restart_syscall)
3020 struct restart_block *restart = ¤t->restart_block;
3021 return restart->fn(restart);
3024 long do_no_restart_syscall(struct restart_block *param)
3029 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
3031 if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
3032 sigset_t newblocked;
3033 /* A set of now blocked but previously unblocked signals. */
3034 sigandnsets(&newblocked, newset, ¤t->blocked);
3035 retarget_shared_pending(tsk, &newblocked);
3037 tsk->blocked = *newset;
3038 recalc_sigpending();
3042 * set_current_blocked - change current->blocked mask
3045 * It is wrong to change ->blocked directly, this helper should be used
3046 * to ensure the process can't miss a shared signal we are going to block.
3048 void set_current_blocked(sigset_t *newset)
3050 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
3051 __set_current_blocked(newset);
3054 void __set_current_blocked(const sigset_t *newset)
3056 struct task_struct *tsk = current;
3059 * In case the signal mask hasn't changed, there is nothing we need
3060 * to do. The current->blocked shouldn't be modified by other task.
3062 if (sigequalsets(&tsk->blocked, newset))
3065 spin_lock_irq(&tsk->sighand->siglock);
3066 __set_task_blocked(tsk, newset);
3067 spin_unlock_irq(&tsk->sighand->siglock);
3071 * This is also useful for kernel threads that want to temporarily
3072 * (or permanently) block certain signals.
3074 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
3075 * interface happily blocks "unblockable" signals like SIGKILL
3078 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
3080 struct task_struct *tsk = current;
3083 /* Lockless, only current can change ->blocked, never from irq */
3085 *oldset = tsk->blocked;
3089 sigorsets(&newset, &tsk->blocked, set);
3092 sigandnsets(&newset, &tsk->blocked, set);
3101 __set_current_blocked(&newset);
3104 EXPORT_SYMBOL(sigprocmask);
3107 * The api helps set app-provided sigmasks.
3109 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
3110 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
3112 * Note that it does set_restore_sigmask() in advance, so it must be always
3113 * paired with restore_saved_sigmask_unless() before return from syscall.
3115 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
3121 if (sigsetsize != sizeof(sigset_t))
3123 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
3126 set_restore_sigmask();
3127 current->saved_sigmask = current->blocked;
3128 set_current_blocked(&kmask);
3133 #ifdef CONFIG_COMPAT
3134 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3141 if (sigsetsize != sizeof(compat_sigset_t))
3143 if (get_compat_sigset(&kmask, umask))
3146 set_restore_sigmask();
3147 current->saved_sigmask = current->blocked;
3148 set_current_blocked(&kmask);
3155 * sys_rt_sigprocmask - change the list of currently blocked signals
3156 * @how: whether to add, remove, or set signals
3157 * @nset: stores pending signals
3158 * @oset: previous value of signal mask if non-null
3159 * @sigsetsize: size of sigset_t type
3161 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3162 sigset_t __user *, oset, size_t, sigsetsize)
3164 sigset_t old_set, new_set;
3167 /* XXX: Don't preclude handling different sized sigset_t's. */
3168 if (sigsetsize != sizeof(sigset_t))
3171 old_set = current->blocked;
3174 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3176 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3178 error = sigprocmask(how, &new_set, NULL);
3184 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3191 #ifdef CONFIG_COMPAT
3192 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3193 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3195 sigset_t old_set = current->blocked;
3197 /* XXX: Don't preclude handling different sized sigset_t's. */
3198 if (sigsetsize != sizeof(sigset_t))
3204 if (get_compat_sigset(&new_set, nset))
3206 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3208 error = sigprocmask(how, &new_set, NULL);
3212 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3216 static void do_sigpending(sigset_t *set)
3218 spin_lock_irq(¤t->sighand->siglock);
3219 sigorsets(set, ¤t->pending.signal,
3220 ¤t->signal->shared_pending.signal);
3221 spin_unlock_irq(¤t->sighand->siglock);
3223 /* Outside the lock because only this thread touches it. */
3224 sigandsets(set, ¤t->blocked, set);
3228 * sys_rt_sigpending - examine a pending signal that has been raised
3230 * @uset: stores pending signals
3231 * @sigsetsize: size of sigset_t type or larger
3233 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3237 if (sigsetsize > sizeof(*uset))
3240 do_sigpending(&set);
3242 if (copy_to_user(uset, &set, sigsetsize))
3248 #ifdef CONFIG_COMPAT
3249 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3250 compat_size_t, sigsetsize)
3254 if (sigsetsize > sizeof(*uset))
3257 do_sigpending(&set);
3259 return put_compat_sigset(uset, &set, sigsetsize);
3263 static const struct {
3264 unsigned char limit, layout;
3266 [SIGILL] = { NSIGILL, SIL_FAULT },
3267 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3268 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3269 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3270 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3272 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3274 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3275 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3276 [SIGSYS] = { NSIGSYS, SIL_SYS },
3279 static bool known_siginfo_layout(unsigned sig, int si_code)
3281 if (si_code == SI_KERNEL)
3283 else if ((si_code > SI_USER)) {
3284 if (sig_specific_sicodes(sig)) {
3285 if (si_code <= sig_sicodes[sig].limit)
3288 else if (si_code <= NSIGPOLL)
3291 else if (si_code >= SI_DETHREAD)
3293 else if (si_code == SI_ASYNCNL)
3298 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3300 enum siginfo_layout layout = SIL_KILL;
3301 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3302 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3303 (si_code <= sig_sicodes[sig].limit)) {
3304 layout = sig_sicodes[sig].layout;
3305 /* Handle the exceptions */
3306 if ((sig == SIGBUS) &&
3307 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3308 layout = SIL_FAULT_MCEERR;
3309 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3310 layout = SIL_FAULT_BNDERR;
3312 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3313 layout = SIL_FAULT_PKUERR;
3315 else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
3316 layout = SIL_FAULT_PERF_EVENT;
3317 else if (IS_ENABLED(CONFIG_SPARC) &&
3318 (sig == SIGILL) && (si_code == ILL_ILLTRP))
3319 layout = SIL_FAULT_TRAPNO;
3320 else if (IS_ENABLED(CONFIG_ALPHA) &&
3322 ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
3323 layout = SIL_FAULT_TRAPNO;
3325 else if (si_code <= NSIGPOLL)
3328 if (si_code == SI_TIMER)
3330 else if (si_code == SI_SIGIO)
3332 else if (si_code < 0)
3338 static inline char __user *si_expansion(const siginfo_t __user *info)
3340 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3343 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3345 char __user *expansion = si_expansion(to);
3346 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3348 if (clear_user(expansion, SI_EXPANSION_SIZE))
3353 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3354 const siginfo_t __user *from)
3356 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3357 char __user *expansion = si_expansion(from);
3358 char buf[SI_EXPANSION_SIZE];
3361 * An unknown si_code might need more than
3362 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3363 * extra bytes are 0. This guarantees copy_siginfo_to_user
3364 * will return this data to userspace exactly.
3366 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3368 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3376 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3377 const siginfo_t __user *from)
3379 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3381 to->si_signo = signo;
3382 return post_copy_siginfo_from_user(to, from);
3385 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3387 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3389 return post_copy_siginfo_from_user(to, from);
3392 #ifdef CONFIG_COMPAT
3394 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3395 * @to: compat siginfo destination
3396 * @from: kernel siginfo source
3398 * Note: This function does not work properly for the SIGCHLD on x32, but
3399 * fortunately it doesn't have to. The only valid callers for this function are
3400 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3401 * The latter does not care because SIGCHLD will never cause a coredump.
3403 void copy_siginfo_to_external32(struct compat_siginfo *to,
3404 const struct kernel_siginfo *from)
3406 memset(to, 0, sizeof(*to));
3408 to->si_signo = from->si_signo;
3409 to->si_errno = from->si_errno;
3410 to->si_code = from->si_code;
3411 switch(siginfo_layout(from->si_signo, from->si_code)) {
3413 to->si_pid = from->si_pid;
3414 to->si_uid = from->si_uid;
3417 to->si_tid = from->si_tid;
3418 to->si_overrun = from->si_overrun;
3419 to->si_int = from->si_int;
3422 to->si_band = from->si_band;
3423 to->si_fd = from->si_fd;
3426 to->si_addr = ptr_to_compat(from->si_addr);
3428 case SIL_FAULT_TRAPNO:
3429 to->si_addr = ptr_to_compat(from->si_addr);
3430 to->si_trapno = from->si_trapno;
3432 case SIL_FAULT_MCEERR:
3433 to->si_addr = ptr_to_compat(from->si_addr);
3434 to->si_addr_lsb = from->si_addr_lsb;
3436 case SIL_FAULT_BNDERR:
3437 to->si_addr = ptr_to_compat(from->si_addr);
3438 to->si_lower = ptr_to_compat(from->si_lower);
3439 to->si_upper = ptr_to_compat(from->si_upper);
3441 case SIL_FAULT_PKUERR:
3442 to->si_addr = ptr_to_compat(from->si_addr);
3443 to->si_pkey = from->si_pkey;
3445 case SIL_FAULT_PERF_EVENT:
3446 to->si_addr = ptr_to_compat(from->si_addr);
3447 to->si_perf_data = from->si_perf_data;
3448 to->si_perf_type = from->si_perf_type;
3449 to->si_perf_flags = from->si_perf_flags;
3452 to->si_pid = from->si_pid;
3453 to->si_uid = from->si_uid;
3454 to->si_status = from->si_status;
3455 to->si_utime = from->si_utime;
3456 to->si_stime = from->si_stime;
3459 to->si_pid = from->si_pid;
3460 to->si_uid = from->si_uid;
3461 to->si_int = from->si_int;
3464 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3465 to->si_syscall = from->si_syscall;
3466 to->si_arch = from->si_arch;
3471 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3472 const struct kernel_siginfo *from)
3474 struct compat_siginfo new;
3476 copy_siginfo_to_external32(&new, from);
3477 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3482 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3483 const struct compat_siginfo *from)
3486 to->si_signo = from->si_signo;
3487 to->si_errno = from->si_errno;
3488 to->si_code = from->si_code;
3489 switch(siginfo_layout(from->si_signo, from->si_code)) {
3491 to->si_pid = from->si_pid;
3492 to->si_uid = from->si_uid;
3495 to->si_tid = from->si_tid;
3496 to->si_overrun = from->si_overrun;
3497 to->si_int = from->si_int;
3500 to->si_band = from->si_band;
3501 to->si_fd = from->si_fd;
3504 to->si_addr = compat_ptr(from->si_addr);
3506 case SIL_FAULT_TRAPNO:
3507 to->si_addr = compat_ptr(from->si_addr);
3508 to->si_trapno = from->si_trapno;
3510 case SIL_FAULT_MCEERR:
3511 to->si_addr = compat_ptr(from->si_addr);
3512 to->si_addr_lsb = from->si_addr_lsb;
3514 case SIL_FAULT_BNDERR:
3515 to->si_addr = compat_ptr(from->si_addr);
3516 to->si_lower = compat_ptr(from->si_lower);
3517 to->si_upper = compat_ptr(from->si_upper);
3519 case SIL_FAULT_PKUERR:
3520 to->si_addr = compat_ptr(from->si_addr);
3521 to->si_pkey = from->si_pkey;
3523 case SIL_FAULT_PERF_EVENT:
3524 to->si_addr = compat_ptr(from->si_addr);
3525 to->si_perf_data = from->si_perf_data;
3526 to->si_perf_type = from->si_perf_type;
3527 to->si_perf_flags = from->si_perf_flags;
3530 to->si_pid = from->si_pid;
3531 to->si_uid = from->si_uid;
3532 to->si_status = from->si_status;
3533 #ifdef CONFIG_X86_X32_ABI
3534 if (in_x32_syscall()) {
3535 to->si_utime = from->_sifields._sigchld_x32._utime;
3536 to->si_stime = from->_sifields._sigchld_x32._stime;
3540 to->si_utime = from->si_utime;
3541 to->si_stime = from->si_stime;
3545 to->si_pid = from->si_pid;
3546 to->si_uid = from->si_uid;
3547 to->si_int = from->si_int;
3550 to->si_call_addr = compat_ptr(from->si_call_addr);
3551 to->si_syscall = from->si_syscall;
3552 to->si_arch = from->si_arch;
3558 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3559 const struct compat_siginfo __user *ufrom)
3561 struct compat_siginfo from;
3563 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3566 from.si_signo = signo;
3567 return post_copy_siginfo_from_user32(to, &from);
3570 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3571 const struct compat_siginfo __user *ufrom)
3573 struct compat_siginfo from;
3575 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3578 return post_copy_siginfo_from_user32(to, &from);
3580 #endif /* CONFIG_COMPAT */
3583 * do_sigtimedwait - wait for queued signals specified in @which
3584 * @which: queued signals to wait for
3585 * @info: if non-null, the signal's siginfo is returned here
3586 * @ts: upper bound on process time suspension
3588 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3589 const struct timespec64 *ts)
3591 ktime_t *to = NULL, timeout = KTIME_MAX;
3592 struct task_struct *tsk = current;
3593 sigset_t mask = *which;
3598 if (!timespec64_valid(ts))
3600 timeout = timespec64_to_ktime(*ts);
3605 * Invert the set of allowed signals to get those we want to block.
3607 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3610 spin_lock_irq(&tsk->sighand->siglock);
3611 sig = dequeue_signal(tsk, &mask, info, &type);
3612 if (!sig && timeout) {
3614 * None ready, temporarily unblock those we're interested
3615 * while we are sleeping in so that we'll be awakened when
3616 * they arrive. Unblocking is always fine, we can avoid
3617 * set_current_blocked().
3619 tsk->real_blocked = tsk->blocked;
3620 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3621 recalc_sigpending();
3622 spin_unlock_irq(&tsk->sighand->siglock);
3624 __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
3625 ret = schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3627 spin_lock_irq(&tsk->sighand->siglock);
3628 __set_task_blocked(tsk, &tsk->real_blocked);
3629 sigemptyset(&tsk->real_blocked);
3630 sig = dequeue_signal(tsk, &mask, info, &type);
3632 spin_unlock_irq(&tsk->sighand->siglock);
3636 return ret ? -EINTR : -EAGAIN;
3640 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3642 * @uthese: queued signals to wait for
3643 * @uinfo: if non-null, the signal's siginfo is returned here
3644 * @uts: upper bound on process time suspension
3645 * @sigsetsize: size of sigset_t type
3647 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3648 siginfo_t __user *, uinfo,
3649 const struct __kernel_timespec __user *, uts,
3653 struct timespec64 ts;
3654 kernel_siginfo_t info;
3657 /* XXX: Don't preclude handling different sized sigset_t's. */
3658 if (sigsetsize != sizeof(sigset_t))
3661 if (copy_from_user(&these, uthese, sizeof(these)))
3665 if (get_timespec64(&ts, uts))
3669 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3671 if (ret > 0 && uinfo) {
3672 if (copy_siginfo_to_user(uinfo, &info))
3679 #ifdef CONFIG_COMPAT_32BIT_TIME
3680 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3681 siginfo_t __user *, uinfo,
3682 const struct old_timespec32 __user *, uts,
3686 struct timespec64 ts;
3687 kernel_siginfo_t info;
3690 if (sigsetsize != sizeof(sigset_t))
3693 if (copy_from_user(&these, uthese, sizeof(these)))
3697 if (get_old_timespec32(&ts, uts))
3701 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3703 if (ret > 0 && uinfo) {
3704 if (copy_siginfo_to_user(uinfo, &info))
3712 #ifdef CONFIG_COMPAT
3713 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3714 struct compat_siginfo __user *, uinfo,
3715 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3718 struct timespec64 t;
3719 kernel_siginfo_t info;
3722 if (sigsetsize != sizeof(sigset_t))
3725 if (get_compat_sigset(&s, uthese))
3729 if (get_timespec64(&t, uts))
3733 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3735 if (ret > 0 && uinfo) {
3736 if (copy_siginfo_to_user32(uinfo, &info))
3743 #ifdef CONFIG_COMPAT_32BIT_TIME
3744 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3745 struct compat_siginfo __user *, uinfo,
3746 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3749 struct timespec64 t;
3750 kernel_siginfo_t info;
3753 if (sigsetsize != sizeof(sigset_t))
3756 if (get_compat_sigset(&s, uthese))
3760 if (get_old_timespec32(&t, uts))
3764 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3766 if (ret > 0 && uinfo) {
3767 if (copy_siginfo_to_user32(uinfo, &info))
3776 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3778 clear_siginfo(info);
3779 info->si_signo = sig;
3781 info->si_code = SI_USER;
3782 info->si_pid = task_tgid_vnr(current);
3783 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3787 * sys_kill - send a signal to a process
3788 * @pid: the PID of the process
3789 * @sig: signal to be sent
3791 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3793 struct kernel_siginfo info;
3795 prepare_kill_siginfo(sig, &info);
3797 return kill_something_info(sig, &info, pid);
3801 * Verify that the signaler and signalee either are in the same pid namespace
3802 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3805 static bool access_pidfd_pidns(struct pid *pid)
3807 struct pid_namespace *active = task_active_pid_ns(current);
3808 struct pid_namespace *p = ns_of_pid(pid);
3821 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
3822 siginfo_t __user *info)
3824 #ifdef CONFIG_COMPAT
3826 * Avoid hooking up compat syscalls and instead handle necessary
3827 * conversions here. Note, this is a stop-gap measure and should not be
3828 * considered a generic solution.
3830 if (in_compat_syscall())
3831 return copy_siginfo_from_user32(
3832 kinfo, (struct compat_siginfo __user *)info);
3834 return copy_siginfo_from_user(kinfo, info);
3837 static struct pid *pidfd_to_pid(const struct file *file)
3841 pid = pidfd_pid(file);
3845 return tgid_pidfd_to_pid(file);
3849 * sys_pidfd_send_signal - Signal a process through a pidfd
3850 * @pidfd: file descriptor of the process
3851 * @sig: signal to send
3852 * @info: signal info
3853 * @flags: future flags
3855 * The syscall currently only signals via PIDTYPE_PID which covers
3856 * kill(<positive-pid>, <signal>. It does not signal threads or process
3858 * In order to extend the syscall to threads and process groups the @flags
3859 * argument should be used. In essence, the @flags argument will determine
3860 * what is signaled and not the file descriptor itself. Put in other words,
3861 * grouping is a property of the flags argument not a property of the file
3864 * Return: 0 on success, negative errno on failure
3866 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3867 siginfo_t __user *, info, unsigned int, flags)
3872 kernel_siginfo_t kinfo;
3874 /* Enforce flags be set to 0 until we add an extension. */
3882 /* Is this a pidfd? */
3883 pid = pidfd_to_pid(f.file);
3890 if (!access_pidfd_pidns(pid))
3894 ret = copy_siginfo_from_user_any(&kinfo, info);
3899 if (unlikely(sig != kinfo.si_signo))
3902 /* Only allow sending arbitrary signals to yourself. */
3904 if ((task_pid(current) != pid) &&
3905 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3908 prepare_kill_siginfo(sig, &kinfo);
3911 ret = kill_pid_info(sig, &kinfo, pid);
3919 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3921 struct task_struct *p;
3925 p = find_task_by_vpid(pid);
3926 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3927 error = check_kill_permission(sig, info, p);
3929 * The null signal is a permissions and process existence
3930 * probe. No signal is actually delivered.
3932 if (!error && sig) {
3933 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3935 * If lock_task_sighand() failed we pretend the task
3936 * dies after receiving the signal. The window is tiny,
3937 * and the signal is private anyway.
3939 if (unlikely(error == -ESRCH))
3948 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3950 struct kernel_siginfo info;
3952 clear_siginfo(&info);
3953 info.si_signo = sig;
3955 info.si_code = SI_TKILL;
3956 info.si_pid = task_tgid_vnr(current);
3957 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3959 return do_send_specific(tgid, pid, sig, &info);
3963 * sys_tgkill - send signal to one specific thread
3964 * @tgid: the thread group ID of the thread
3965 * @pid: the PID of the thread
3966 * @sig: signal to be sent
3968 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3969 * exists but it's not belonging to the target process anymore. This
3970 * method solves the problem of threads exiting and PIDs getting reused.
3972 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3974 /* This is only valid for single tasks */
3975 if (pid <= 0 || tgid <= 0)
3978 return do_tkill(tgid, pid, sig);
3982 * sys_tkill - send signal to one specific task
3983 * @pid: the PID of the task
3984 * @sig: signal to be sent
3986 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3988 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3990 /* This is only valid for single tasks */
3994 return do_tkill(0, pid, sig);
3997 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3999 /* Not even root can pretend to send signals from the kernel.
4000 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4002 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4003 (task_pid_vnr(current) != pid))
4006 /* POSIX.1b doesn't mention process groups. */
4007 return kill_proc_info(sig, info, pid);
4011 * sys_rt_sigqueueinfo - send signal information to a signal
4012 * @pid: the PID of the thread
4013 * @sig: signal to be sent
4014 * @uinfo: signal info to be sent
4016 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
4017 siginfo_t __user *, uinfo)
4019 kernel_siginfo_t info;
4020 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4023 return do_rt_sigqueueinfo(pid, sig, &info);
4026 #ifdef CONFIG_COMPAT
4027 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
4030 struct compat_siginfo __user *, uinfo)
4032 kernel_siginfo_t info;
4033 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4036 return do_rt_sigqueueinfo(pid, sig, &info);
4040 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
4042 /* This is only valid for single tasks */
4043 if (pid <= 0 || tgid <= 0)
4046 /* Not even root can pretend to send signals from the kernel.
4047 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4049 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4050 (task_pid_vnr(current) != pid))
4053 return do_send_specific(tgid, pid, sig, info);
4056 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
4057 siginfo_t __user *, uinfo)
4059 kernel_siginfo_t info;
4060 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4063 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4066 #ifdef CONFIG_COMPAT
4067 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
4071 struct compat_siginfo __user *, uinfo)
4073 kernel_siginfo_t info;
4074 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4077 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4082 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
4084 void kernel_sigaction(int sig, __sighandler_t action)
4086 spin_lock_irq(¤t->sighand->siglock);
4087 current->sighand->action[sig - 1].sa.sa_handler = action;
4088 if (action == SIG_IGN) {
4092 sigaddset(&mask, sig);
4094 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
4095 flush_sigqueue_mask(&mask, ¤t->pending);
4096 recalc_sigpending();
4098 spin_unlock_irq(¤t->sighand->siglock);
4100 EXPORT_SYMBOL(kernel_sigaction);
4102 void __weak sigaction_compat_abi(struct k_sigaction *act,
4103 struct k_sigaction *oact)
4107 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
4109 struct task_struct *p = current, *t;
4110 struct k_sigaction *k;
4113 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
4116 k = &p->sighand->action[sig-1];
4118 spin_lock_irq(&p->sighand->siglock);
4119 if (k->sa.sa_flags & SA_IMMUTABLE) {
4120 spin_unlock_irq(&p->sighand->siglock);
4127 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
4128 * e.g. by having an architecture use the bit in their uapi.
4130 BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
4133 * Clear unknown flag bits in order to allow userspace to detect missing
4134 * support for flag bits and to allow the kernel to use non-uapi bits
4138 act->sa.sa_flags &= UAPI_SA_FLAGS;
4140 oact->sa.sa_flags &= UAPI_SA_FLAGS;
4142 sigaction_compat_abi(act, oact);
4145 sigdelsetmask(&act->sa.sa_mask,
4146 sigmask(SIGKILL) | sigmask(SIGSTOP));
4150 * "Setting a signal action to SIG_IGN for a signal that is
4151 * pending shall cause the pending signal to be discarded,
4152 * whether or not it is blocked."
4154 * "Setting a signal action to SIG_DFL for a signal that is
4155 * pending and whose default action is to ignore the signal
4156 * (for example, SIGCHLD), shall cause the pending signal to
4157 * be discarded, whether or not it is blocked"
4159 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
4161 sigaddset(&mask, sig);
4162 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
4163 for_each_thread(p, t)
4164 flush_sigqueue_mask(&mask, &t->pending);
4168 spin_unlock_irq(&p->sighand->siglock);
4172 #ifdef CONFIG_DYNAMIC_SIGFRAME
4173 static inline void sigaltstack_lock(void)
4174 __acquires(¤t->sighand->siglock)
4176 spin_lock_irq(¤t->sighand->siglock);
4179 static inline void sigaltstack_unlock(void)
4180 __releases(¤t->sighand->siglock)
4182 spin_unlock_irq(¤t->sighand->siglock);
4185 static inline void sigaltstack_lock(void) { }
4186 static inline void sigaltstack_unlock(void) { }
4190 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4193 struct task_struct *t = current;
4197 memset(oss, 0, sizeof(stack_t));
4198 oss->ss_sp = (void __user *) t->sas_ss_sp;
4199 oss->ss_size = t->sas_ss_size;
4200 oss->ss_flags = sas_ss_flags(sp) |
4201 (current->sas_ss_flags & SS_FLAG_BITS);
4205 void __user *ss_sp = ss->ss_sp;
4206 size_t ss_size = ss->ss_size;
4207 unsigned ss_flags = ss->ss_flags;
4210 if (unlikely(on_sig_stack(sp)))
4213 ss_mode = ss_flags & ~SS_FLAG_BITS;
4214 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4219 * Return before taking any locks if no actual
4220 * sigaltstack changes were requested.
4222 if (t->sas_ss_sp == (unsigned long)ss_sp &&
4223 t->sas_ss_size == ss_size &&
4224 t->sas_ss_flags == ss_flags)
4228 if (ss_mode == SS_DISABLE) {
4232 if (unlikely(ss_size < min_ss_size))
4234 if (!sigaltstack_size_valid(ss_size))
4238 t->sas_ss_sp = (unsigned long) ss_sp;
4239 t->sas_ss_size = ss_size;
4240 t->sas_ss_flags = ss_flags;
4242 sigaltstack_unlock();
4247 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4251 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4253 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4254 current_user_stack_pointer(),
4256 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4261 int restore_altstack(const stack_t __user *uss)
4264 if (copy_from_user(&new, uss, sizeof(stack_t)))
4266 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4268 /* squash all but EFAULT for now */
4272 int __save_altstack(stack_t __user *uss, unsigned long sp)
4274 struct task_struct *t = current;
4275 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4276 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4277 __put_user(t->sas_ss_size, &uss->ss_size);
4281 #ifdef CONFIG_COMPAT
4282 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4283 compat_stack_t __user *uoss_ptr)
4289 compat_stack_t uss32;
4290 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4292 uss.ss_sp = compat_ptr(uss32.ss_sp);
4293 uss.ss_flags = uss32.ss_flags;
4294 uss.ss_size = uss32.ss_size;
4296 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4297 compat_user_stack_pointer(),
4298 COMPAT_MINSIGSTKSZ);
4299 if (ret >= 0 && uoss_ptr) {
4301 memset(&old, 0, sizeof(old));
4302 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4303 old.ss_flags = uoss.ss_flags;
4304 old.ss_size = uoss.ss_size;
4305 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4311 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4312 const compat_stack_t __user *, uss_ptr,
4313 compat_stack_t __user *, uoss_ptr)
4315 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4318 int compat_restore_altstack(const compat_stack_t __user *uss)
4320 int err = do_compat_sigaltstack(uss, NULL);
4321 /* squash all but -EFAULT for now */
4322 return err == -EFAULT ? err : 0;
4325 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4328 struct task_struct *t = current;
4329 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4331 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4332 __put_user(t->sas_ss_size, &uss->ss_size);
4337 #ifdef __ARCH_WANT_SYS_SIGPENDING
4340 * sys_sigpending - examine pending signals
4341 * @uset: where mask of pending signal is returned
4343 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4347 if (sizeof(old_sigset_t) > sizeof(*uset))
4350 do_sigpending(&set);
4352 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4358 #ifdef CONFIG_COMPAT
4359 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4363 do_sigpending(&set);
4365 return put_user(set.sig[0], set32);
4371 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4373 * sys_sigprocmask - examine and change blocked signals
4374 * @how: whether to add, remove, or set signals
4375 * @nset: signals to add or remove (if non-null)
4376 * @oset: previous value of signal mask if non-null
4378 * Some platforms have their own version with special arguments;
4379 * others support only sys_rt_sigprocmask.
4382 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4383 old_sigset_t __user *, oset)
4385 old_sigset_t old_set, new_set;
4386 sigset_t new_blocked;
4388 old_set = current->blocked.sig[0];
4391 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4394 new_blocked = current->blocked;
4398 sigaddsetmask(&new_blocked, new_set);
4401 sigdelsetmask(&new_blocked, new_set);
4404 new_blocked.sig[0] = new_set;
4410 set_current_blocked(&new_blocked);
4414 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4420 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4422 #ifndef CONFIG_ODD_RT_SIGACTION
4424 * sys_rt_sigaction - alter an action taken by a process
4425 * @sig: signal to be sent
4426 * @act: new sigaction
4427 * @oact: used to save the previous sigaction
4428 * @sigsetsize: size of sigset_t type
4430 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4431 const struct sigaction __user *, act,
4432 struct sigaction __user *, oact,
4435 struct k_sigaction new_sa, old_sa;
4438 /* XXX: Don't preclude handling different sized sigset_t's. */
4439 if (sigsetsize != sizeof(sigset_t))
4442 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4445 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4449 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4454 #ifdef CONFIG_COMPAT
4455 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4456 const struct compat_sigaction __user *, act,
4457 struct compat_sigaction __user *, oact,
4458 compat_size_t, sigsetsize)
4460 struct k_sigaction new_ka, old_ka;
4461 #ifdef __ARCH_HAS_SA_RESTORER
4462 compat_uptr_t restorer;
4466 /* XXX: Don't preclude handling different sized sigset_t's. */
4467 if (sigsetsize != sizeof(compat_sigset_t))
4471 compat_uptr_t handler;
4472 ret = get_user(handler, &act->sa_handler);
4473 new_ka.sa.sa_handler = compat_ptr(handler);
4474 #ifdef __ARCH_HAS_SA_RESTORER
4475 ret |= get_user(restorer, &act->sa_restorer);
4476 new_ka.sa.sa_restorer = compat_ptr(restorer);
4478 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4479 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4484 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4486 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4488 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4489 sizeof(oact->sa_mask));
4490 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4491 #ifdef __ARCH_HAS_SA_RESTORER
4492 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4493 &oact->sa_restorer);
4499 #endif /* !CONFIG_ODD_RT_SIGACTION */
4501 #ifdef CONFIG_OLD_SIGACTION
4502 SYSCALL_DEFINE3(sigaction, int, sig,
4503 const struct old_sigaction __user *, act,
4504 struct old_sigaction __user *, oact)
4506 struct k_sigaction new_ka, old_ka;
4511 if (!access_ok(act, sizeof(*act)) ||
4512 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4513 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4514 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4515 __get_user(mask, &act->sa_mask))
4517 #ifdef __ARCH_HAS_KA_RESTORER
4518 new_ka.ka_restorer = NULL;
4520 siginitset(&new_ka.sa.sa_mask, mask);
4523 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4526 if (!access_ok(oact, sizeof(*oact)) ||
4527 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4528 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4529 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4530 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4537 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4538 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4539 const struct compat_old_sigaction __user *, act,
4540 struct compat_old_sigaction __user *, oact)
4542 struct k_sigaction new_ka, old_ka;
4544 compat_old_sigset_t mask;
4545 compat_uptr_t handler, restorer;
4548 if (!access_ok(act, sizeof(*act)) ||
4549 __get_user(handler, &act->sa_handler) ||
4550 __get_user(restorer, &act->sa_restorer) ||
4551 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4552 __get_user(mask, &act->sa_mask))
4555 #ifdef __ARCH_HAS_KA_RESTORER
4556 new_ka.ka_restorer = NULL;
4558 new_ka.sa.sa_handler = compat_ptr(handler);
4559 new_ka.sa.sa_restorer = compat_ptr(restorer);
4560 siginitset(&new_ka.sa.sa_mask, mask);
4563 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4566 if (!access_ok(oact, sizeof(*oact)) ||
4567 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4568 &oact->sa_handler) ||
4569 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4570 &oact->sa_restorer) ||
4571 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4572 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4579 #ifdef CONFIG_SGETMASK_SYSCALL
4582 * For backwards compatibility. Functionality superseded by sigprocmask.
4584 SYSCALL_DEFINE0(sgetmask)
4587 return current->blocked.sig[0];
4590 SYSCALL_DEFINE1(ssetmask, int, newmask)
4592 int old = current->blocked.sig[0];
4595 siginitset(&newset, newmask);
4596 set_current_blocked(&newset);
4600 #endif /* CONFIG_SGETMASK_SYSCALL */
4602 #ifdef __ARCH_WANT_SYS_SIGNAL
4604 * For backwards compatibility. Functionality superseded by sigaction.
4606 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4608 struct k_sigaction new_sa, old_sa;
4611 new_sa.sa.sa_handler = handler;
4612 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4613 sigemptyset(&new_sa.sa.sa_mask);
4615 ret = do_sigaction(sig, &new_sa, &old_sa);
4617 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4619 #endif /* __ARCH_WANT_SYS_SIGNAL */
4621 #ifdef __ARCH_WANT_SYS_PAUSE
4623 SYSCALL_DEFINE0(pause)
4625 while (!signal_pending(current)) {
4626 __set_current_state(TASK_INTERRUPTIBLE);
4629 return -ERESTARTNOHAND;
4634 static int sigsuspend(sigset_t *set)
4636 current->saved_sigmask = current->blocked;
4637 set_current_blocked(set);
4639 while (!signal_pending(current)) {
4640 __set_current_state(TASK_INTERRUPTIBLE);
4643 set_restore_sigmask();
4644 return -ERESTARTNOHAND;
4648 * sys_rt_sigsuspend - replace the signal mask for a value with the
4649 * @unewset value until a signal is received
4650 * @unewset: new signal mask value
4651 * @sigsetsize: size of sigset_t type
4653 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4657 /* XXX: Don't preclude handling different sized sigset_t's. */
4658 if (sigsetsize != sizeof(sigset_t))
4661 if (copy_from_user(&newset, unewset, sizeof(newset)))
4663 return sigsuspend(&newset);
4666 #ifdef CONFIG_COMPAT
4667 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4671 /* XXX: Don't preclude handling different sized sigset_t's. */
4672 if (sigsetsize != sizeof(sigset_t))
4675 if (get_compat_sigset(&newset, unewset))
4677 return sigsuspend(&newset);
4681 #ifdef CONFIG_OLD_SIGSUSPEND
4682 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4685 siginitset(&blocked, mask);
4686 return sigsuspend(&blocked);
4689 #ifdef CONFIG_OLD_SIGSUSPEND3
4690 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4693 siginitset(&blocked, mask);
4694 return sigsuspend(&blocked);
4698 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4703 static inline void siginfo_buildtime_checks(void)
4705 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4707 /* Verify the offsets in the two siginfos match */
4708 #define CHECK_OFFSET(field) \
4709 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4712 CHECK_OFFSET(si_pid);
4713 CHECK_OFFSET(si_uid);
4716 CHECK_OFFSET(si_tid);
4717 CHECK_OFFSET(si_overrun);
4718 CHECK_OFFSET(si_value);
4721 CHECK_OFFSET(si_pid);
4722 CHECK_OFFSET(si_uid);
4723 CHECK_OFFSET(si_value);
4726 CHECK_OFFSET(si_pid);
4727 CHECK_OFFSET(si_uid);
4728 CHECK_OFFSET(si_status);
4729 CHECK_OFFSET(si_utime);
4730 CHECK_OFFSET(si_stime);
4733 CHECK_OFFSET(si_addr);
4734 CHECK_OFFSET(si_trapno);
4735 CHECK_OFFSET(si_addr_lsb);
4736 CHECK_OFFSET(si_lower);
4737 CHECK_OFFSET(si_upper);
4738 CHECK_OFFSET(si_pkey);
4739 CHECK_OFFSET(si_perf_data);
4740 CHECK_OFFSET(si_perf_type);
4741 CHECK_OFFSET(si_perf_flags);
4744 CHECK_OFFSET(si_band);
4745 CHECK_OFFSET(si_fd);
4748 CHECK_OFFSET(si_call_addr);
4749 CHECK_OFFSET(si_syscall);
4750 CHECK_OFFSET(si_arch);
4754 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4755 offsetof(struct siginfo, si_addr));
4756 if (sizeof(int) == sizeof(void __user *)) {
4757 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4758 sizeof(void __user *));
4760 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4761 sizeof_field(struct siginfo, si_uid)) !=
4762 sizeof(void __user *));
4763 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4764 offsetof(struct siginfo, si_uid));
4766 #ifdef CONFIG_COMPAT
4767 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4768 offsetof(struct compat_siginfo, si_addr));
4769 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4770 sizeof(compat_uptr_t));
4771 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4772 sizeof_field(struct siginfo, si_pid));
4776 void __init signals_init(void)
4778 siginfo_buildtime_checks();
4780 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT);
4783 #ifdef CONFIG_KGDB_KDB
4784 #include <linux/kdb.h>
4786 * kdb_send_sig - Allows kdb to send signals without exposing
4787 * signal internals. This function checks if the required locks are
4788 * available before calling the main signal code, to avoid kdb
4791 void kdb_send_sig(struct task_struct *t, int sig)
4793 static struct task_struct *kdb_prev_t;
4795 if (!spin_trylock(&t->sighand->siglock)) {
4796 kdb_printf("Can't do kill command now.\n"
4797 "The sigmask lock is held somewhere else in "
4798 "kernel, try again later\n");
4801 new_t = kdb_prev_t != t;
4803 if (!task_is_running(t) && new_t) {
4804 spin_unlock(&t->sighand->siglock);
4805 kdb_printf("Process is not RUNNING, sending a signal from "
4806 "kdb risks deadlock\n"
4807 "on the run queue locks. "
4808 "The signal has _not_ been sent.\n"
4809 "Reissue the kill command if you want to risk "
4813 ret = send_signal_locked(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4814 spin_unlock(&t->sighand->siglock);
4816 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4819 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4821 #endif /* CONFIG_KGDB_KDB */