1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
9 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
10 * Changes to use preallocated sigqueue structures
11 * to allow signals to be sent reliably.
14 #include <linux/slab.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/debug.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/sched/cputime.h>
23 #include <linux/file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/tty.h>
27 #include <linux/binfmts.h>
28 #include <linux/coredump.h>
29 #include <linux/security.h>
30 #include <linux/syscalls.h>
31 #include <linux/ptrace.h>
32 #include <linux/signal.h>
33 #include <linux/signalfd.h>
34 #include <linux/ratelimit.h>
35 #include <linux/tracehook.h>
36 #include <linux/capability.h>
37 #include <linux/freezer.h>
38 #include <linux/pid_namespace.h>
39 #include <linux/nsproxy.h>
40 #include <linux/user_namespace.h>
41 #include <linux/uprobes.h>
42 #include <linux/compat.h>
43 #include <linux/cn_proc.h>
44 #include <linux/compiler.h>
45 #include <linux/posix-timers.h>
46 #include <linux/livepatch.h>
47 #include <linux/cgroup.h>
48 #include <linux/audit.h>
50 #define CREATE_TRACE_POINTS
51 #include <trace/events/signal.h>
53 #include <asm/param.h>
54 #include <linux/uaccess.h>
55 #include <asm/unistd.h>
56 #include <asm/siginfo.h>
57 #include <asm/cacheflush.h>
60 * SLAB caches for signal bits.
63 static struct kmem_cache *sigqueue_cachep;
65 int print_fatal_signals __read_mostly;
67 static void __user *sig_handler(struct task_struct *t, int sig)
69 return t->sighand->action[sig - 1].sa.sa_handler;
72 static inline bool sig_handler_ignored(void __user *handler, int sig)
74 /* Is it explicitly or implicitly ignored? */
75 return handler == SIG_IGN ||
76 (handler == SIG_DFL && sig_kernel_ignore(sig));
79 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
83 handler = sig_handler(t, sig);
85 /* SIGKILL and SIGSTOP may not be sent to the global init */
86 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
89 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
90 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
93 return sig_handler_ignored(handler, sig);
96 static bool sig_ignored(struct task_struct *t, int sig, bool force)
99 * Blocked signals are never ignored, since the
100 * signal handler may change by the time it is
103 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
107 * Tracers may want to know about even ignored signal unless it
108 * is SIGKILL which can't be reported anyway but can be ignored
109 * by SIGNAL_UNKILLABLE task.
111 if (t->ptrace && sig != SIGKILL)
114 return sig_task_ignored(t, sig, force);
118 * Re-calculate pending state from the set of locally pending
119 * signals, globally pending signals, and blocked signals.
121 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
126 switch (_NSIG_WORDS) {
128 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
129 ready |= signal->sig[i] &~ blocked->sig[i];
132 case 4: ready = signal->sig[3] &~ blocked->sig[3];
133 ready |= signal->sig[2] &~ blocked->sig[2];
134 ready |= signal->sig[1] &~ blocked->sig[1];
135 ready |= signal->sig[0] &~ blocked->sig[0];
138 case 2: ready = signal->sig[1] &~ blocked->sig[1];
139 ready |= signal->sig[0] &~ blocked->sig[0];
142 case 1: ready = signal->sig[0] &~ blocked->sig[0];
147 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
149 static bool recalc_sigpending_tsk(struct task_struct *t)
151 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
152 PENDING(&t->pending, &t->blocked) ||
153 PENDING(&t->signal->shared_pending, &t->blocked) ||
154 cgroup_task_frozen(t)) {
155 set_tsk_thread_flag(t, TIF_SIGPENDING);
160 * We must never clear the flag in another thread, or in current
161 * when it's possible the current syscall is returning -ERESTART*.
162 * So we don't clear it here, and only callers who know they should do.
168 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
169 * This is superfluous when called on current, the wakeup is a harmless no-op.
171 void recalc_sigpending_and_wake(struct task_struct *t)
173 if (recalc_sigpending_tsk(t))
174 signal_wake_up(t, 0);
177 void recalc_sigpending(void)
179 if (!recalc_sigpending_tsk(current) && !freezing(current) &&
180 !klp_patch_pending(current))
181 clear_thread_flag(TIF_SIGPENDING);
184 EXPORT_SYMBOL(recalc_sigpending);
186 void calculate_sigpending(void)
188 /* Have any signals or users of TIF_SIGPENDING been delayed
191 spin_lock_irq(¤t->sighand->siglock);
192 set_tsk_thread_flag(current, TIF_SIGPENDING);
194 spin_unlock_irq(¤t->sighand->siglock);
197 /* Given the mask, find the first available signal that should be serviced. */
199 #define SYNCHRONOUS_MASK \
200 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
201 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
203 int next_signal(struct sigpending *pending, sigset_t *mask)
205 unsigned long i, *s, *m, x;
208 s = pending->signal.sig;
212 * Handle the first word specially: it contains the
213 * synchronous signals that need to be dequeued first.
217 if (x & SYNCHRONOUS_MASK)
218 x &= SYNCHRONOUS_MASK;
223 switch (_NSIG_WORDS) {
225 for (i = 1; i < _NSIG_WORDS; ++i) {
229 sig = ffz(~x) + i*_NSIG_BPW + 1;
238 sig = ffz(~x) + _NSIG_BPW + 1;
249 static inline void print_dropped_signal(int sig)
251 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
253 if (!print_fatal_signals)
256 if (!__ratelimit(&ratelimit_state))
259 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
260 current->comm, current->pid, sig);
264 * task_set_jobctl_pending - set jobctl pending bits
266 * @mask: pending bits to set
268 * Clear @mask from @task->jobctl. @mask must be subset of
269 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
270 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
271 * cleared. If @task is already being killed or exiting, this function
275 * Must be called with @task->sighand->siglock held.
278 * %true if @mask is set, %false if made noop because @task was dying.
280 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
282 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
283 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
284 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
286 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
289 if (mask & JOBCTL_STOP_SIGMASK)
290 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
292 task->jobctl |= mask;
297 * task_clear_jobctl_trapping - clear jobctl trapping bit
300 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
301 * Clear it and wake up the ptracer. Note that we don't need any further
302 * locking. @task->siglock guarantees that @task->parent points to the
306 * Must be called with @task->sighand->siglock held.
308 void task_clear_jobctl_trapping(struct task_struct *task)
310 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
311 task->jobctl &= ~JOBCTL_TRAPPING;
312 smp_mb(); /* advised by wake_up_bit() */
313 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
318 * task_clear_jobctl_pending - clear jobctl pending bits
320 * @mask: pending bits to clear
322 * Clear @mask from @task->jobctl. @mask must be subset of
323 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
324 * STOP bits are cleared together.
326 * If clearing of @mask leaves no stop or trap pending, this function calls
327 * task_clear_jobctl_trapping().
330 * Must be called with @task->sighand->siglock held.
332 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
334 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
336 if (mask & JOBCTL_STOP_PENDING)
337 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
339 task->jobctl &= ~mask;
341 if (!(task->jobctl & JOBCTL_PENDING_MASK))
342 task_clear_jobctl_trapping(task);
346 * task_participate_group_stop - participate in a group stop
347 * @task: task participating in a group stop
349 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
350 * Group stop states are cleared and the group stop count is consumed if
351 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
352 * stop, the appropriate %SIGNAL_* flags are set.
355 * Must be called with @task->sighand->siglock held.
358 * %true if group stop completion should be notified to the parent, %false
361 static bool task_participate_group_stop(struct task_struct *task)
363 struct signal_struct *sig = task->signal;
364 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
366 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
368 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
373 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
374 sig->group_stop_count--;
377 * Tell the caller to notify completion iff we are entering into a
378 * fresh group stop. Read comment in do_signal_stop() for details.
380 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
381 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
387 void task_join_group_stop(struct task_struct *task)
389 /* Have the new thread join an on-going signal group stop */
390 unsigned long jobctl = current->jobctl;
391 if (jobctl & JOBCTL_STOP_PENDING) {
392 struct signal_struct *sig = current->signal;
393 unsigned long signr = jobctl & JOBCTL_STOP_SIGMASK;
394 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
395 if (task_set_jobctl_pending(task, signr | gstop)) {
396 sig->group_stop_count++;
402 * allocate a new signal queue record
403 * - this may be called without locks if and only if t == current, otherwise an
404 * appropriate lock must be held to stop the target task from exiting
406 static struct sigqueue *
407 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
409 struct sigqueue *q = NULL;
410 struct user_struct *user;
413 * Protect access to @t credentials. This can go away when all
414 * callers hold rcu read lock.
417 user = get_uid(__task_cred(t)->user);
418 atomic_inc(&user->sigpending);
421 if (override_rlimit ||
422 atomic_read(&user->sigpending) <=
423 task_rlimit(t, RLIMIT_SIGPENDING)) {
424 q = kmem_cache_alloc(sigqueue_cachep, flags);
426 print_dropped_signal(sig);
429 if (unlikely(q == NULL)) {
430 atomic_dec(&user->sigpending);
433 INIT_LIST_HEAD(&q->list);
441 static void __sigqueue_free(struct sigqueue *q)
443 if (q->flags & SIGQUEUE_PREALLOC)
445 atomic_dec(&q->user->sigpending);
447 kmem_cache_free(sigqueue_cachep, q);
450 void flush_sigqueue(struct sigpending *queue)
454 sigemptyset(&queue->signal);
455 while (!list_empty(&queue->list)) {
456 q = list_entry(queue->list.next, struct sigqueue , list);
457 list_del_init(&q->list);
463 * Flush all pending signals for this kthread.
465 void flush_signals(struct task_struct *t)
469 spin_lock_irqsave(&t->sighand->siglock, flags);
470 clear_tsk_thread_flag(t, TIF_SIGPENDING);
471 flush_sigqueue(&t->pending);
472 flush_sigqueue(&t->signal->shared_pending);
473 spin_unlock_irqrestore(&t->sighand->siglock, flags);
475 EXPORT_SYMBOL(flush_signals);
477 #ifdef CONFIG_POSIX_TIMERS
478 static void __flush_itimer_signals(struct sigpending *pending)
480 sigset_t signal, retain;
481 struct sigqueue *q, *n;
483 signal = pending->signal;
484 sigemptyset(&retain);
486 list_for_each_entry_safe(q, n, &pending->list, list) {
487 int sig = q->info.si_signo;
489 if (likely(q->info.si_code != SI_TIMER)) {
490 sigaddset(&retain, sig);
492 sigdelset(&signal, sig);
493 list_del_init(&q->list);
498 sigorsets(&pending->signal, &signal, &retain);
501 void flush_itimer_signals(void)
503 struct task_struct *tsk = current;
506 spin_lock_irqsave(&tsk->sighand->siglock, flags);
507 __flush_itimer_signals(&tsk->pending);
508 __flush_itimer_signals(&tsk->signal->shared_pending);
509 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
513 void ignore_signals(struct task_struct *t)
517 for (i = 0; i < _NSIG; ++i)
518 t->sighand->action[i].sa.sa_handler = SIG_IGN;
524 * Flush all handlers for a task.
528 flush_signal_handlers(struct task_struct *t, int force_default)
531 struct k_sigaction *ka = &t->sighand->action[0];
532 for (i = _NSIG ; i != 0 ; i--) {
533 if (force_default || ka->sa.sa_handler != SIG_IGN)
534 ka->sa.sa_handler = SIG_DFL;
536 #ifdef __ARCH_HAS_SA_RESTORER
537 ka->sa.sa_restorer = NULL;
539 sigemptyset(&ka->sa.sa_mask);
544 bool unhandled_signal(struct task_struct *tsk, int sig)
546 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
547 if (is_global_init(tsk))
550 if (handler != SIG_IGN && handler != SIG_DFL)
553 /* if ptraced, let the tracer determine */
557 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
560 struct sigqueue *q, *first = NULL;
563 * Collect the siginfo appropriate to this signal. Check if
564 * there is another siginfo for the same signal.
566 list_for_each_entry(q, &list->list, list) {
567 if (q->info.si_signo == sig) {
574 sigdelset(&list->signal, sig);
578 list_del_init(&first->list);
579 copy_siginfo(info, &first->info);
582 (first->flags & SIGQUEUE_PREALLOC) &&
583 (info->si_code == SI_TIMER) &&
584 (info->si_sys_private);
586 __sigqueue_free(first);
589 * Ok, it wasn't in the queue. This must be
590 * a fast-pathed signal or we must have been
591 * out of queue space. So zero out the info.
594 info->si_signo = sig;
596 info->si_code = SI_USER;
602 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
603 kernel_siginfo_t *info, bool *resched_timer)
605 int sig = next_signal(pending, mask);
608 collect_signal(sig, pending, info, resched_timer);
613 * Dequeue a signal and return the element to the caller, which is
614 * expected to free it.
616 * All callers have to hold the siglock.
618 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
620 bool resched_timer = false;
623 /* We only dequeue private signals from ourselves, we don't let
624 * signalfd steal them
626 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
628 signr = __dequeue_signal(&tsk->signal->shared_pending,
629 mask, info, &resched_timer);
630 #ifdef CONFIG_POSIX_TIMERS
634 * itimers are process shared and we restart periodic
635 * itimers in the signal delivery path to prevent DoS
636 * attacks in the high resolution timer case. This is
637 * compliant with the old way of self-restarting
638 * itimers, as the SIGALRM is a legacy signal and only
639 * queued once. Changing the restart behaviour to
640 * restart the timer in the signal dequeue path is
641 * reducing the timer noise on heavy loaded !highres
644 if (unlikely(signr == SIGALRM)) {
645 struct hrtimer *tmr = &tsk->signal->real_timer;
647 if (!hrtimer_is_queued(tmr) &&
648 tsk->signal->it_real_incr != 0) {
649 hrtimer_forward(tmr, tmr->base->get_time(),
650 tsk->signal->it_real_incr);
651 hrtimer_restart(tmr);
661 if (unlikely(sig_kernel_stop(signr))) {
663 * Set a marker that we have dequeued a stop signal. Our
664 * caller might release the siglock and then the pending
665 * stop signal it is about to process is no longer in the
666 * pending bitmasks, but must still be cleared by a SIGCONT
667 * (and overruled by a SIGKILL). So those cases clear this
668 * shared flag after we've set it. Note that this flag may
669 * remain set after the signal we return is ignored or
670 * handled. That doesn't matter because its only purpose
671 * is to alert stop-signal processing code when another
672 * processor has come along and cleared the flag.
674 current->jobctl |= JOBCTL_STOP_DEQUEUED;
676 #ifdef CONFIG_POSIX_TIMERS
679 * Release the siglock to ensure proper locking order
680 * of timer locks outside of siglocks. Note, we leave
681 * irqs disabled here, since the posix-timers code is
682 * about to disable them again anyway.
684 spin_unlock(&tsk->sighand->siglock);
685 posixtimer_rearm(info);
686 spin_lock(&tsk->sighand->siglock);
688 /* Don't expose the si_sys_private value to userspace */
689 info->si_sys_private = 0;
694 EXPORT_SYMBOL_GPL(dequeue_signal);
696 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
698 struct task_struct *tsk = current;
699 struct sigpending *pending = &tsk->pending;
700 struct sigqueue *q, *sync = NULL;
703 * Might a synchronous signal be in the queue?
705 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
709 * Return the first synchronous signal in the queue.
711 list_for_each_entry(q, &pending->list, list) {
712 /* Synchronous signals have a postive si_code */
713 if ((q->info.si_code > SI_USER) &&
714 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
722 * Check if there is another siginfo for the same signal.
724 list_for_each_entry_continue(q, &pending->list, list) {
725 if (q->info.si_signo == sync->info.si_signo)
729 sigdelset(&pending->signal, sync->info.si_signo);
732 list_del_init(&sync->list);
733 copy_siginfo(info, &sync->info);
734 __sigqueue_free(sync);
735 return info->si_signo;
739 * Tell a process that it has a new active signal..
741 * NOTE! we rely on the previous spin_lock to
742 * lock interrupts for us! We can only be called with
743 * "siglock" held, and the local interrupt must
744 * have been disabled when that got acquired!
746 * No need to set need_resched since signal event passing
747 * goes through ->blocked
749 void signal_wake_up_state(struct task_struct *t, unsigned int state)
751 set_tsk_thread_flag(t, TIF_SIGPENDING);
753 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
754 * case. We don't check t->state here because there is a race with it
755 * executing another processor and just now entering stopped state.
756 * By using wake_up_state, we ensure the process will wake up and
757 * handle its death signal.
759 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
764 * Remove signals in mask from the pending set and queue.
765 * Returns 1 if any signals were found.
767 * All callers must be holding the siglock.
769 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
771 struct sigqueue *q, *n;
774 sigandsets(&m, mask, &s->signal);
775 if (sigisemptyset(&m))
778 sigandnsets(&s->signal, &s->signal, mask);
779 list_for_each_entry_safe(q, n, &s->list, list) {
780 if (sigismember(mask, q->info.si_signo)) {
781 list_del_init(&q->list);
787 static inline int is_si_special(const struct kernel_siginfo *info)
789 return info <= SEND_SIG_PRIV;
792 static inline bool si_fromuser(const struct kernel_siginfo *info)
794 return info == SEND_SIG_NOINFO ||
795 (!is_si_special(info) && SI_FROMUSER(info));
799 * called with RCU read lock from check_kill_permission()
801 static bool kill_ok_by_cred(struct task_struct *t)
803 const struct cred *cred = current_cred();
804 const struct cred *tcred = __task_cred(t);
806 return uid_eq(cred->euid, tcred->suid) ||
807 uid_eq(cred->euid, tcred->uid) ||
808 uid_eq(cred->uid, tcred->suid) ||
809 uid_eq(cred->uid, tcred->uid) ||
810 ns_capable(tcred->user_ns, CAP_KILL);
814 * Bad permissions for sending the signal
815 * - the caller must hold the RCU read lock
817 static int check_kill_permission(int sig, struct kernel_siginfo *info,
818 struct task_struct *t)
823 if (!valid_signal(sig))
826 if (!si_fromuser(info))
829 error = audit_signal_info(sig, t); /* Let audit system see the signal */
833 if (!same_thread_group(current, t) &&
834 !kill_ok_by_cred(t)) {
837 sid = task_session(t);
839 * We don't return the error if sid == NULL. The
840 * task was unhashed, the caller must notice this.
842 if (!sid || sid == task_session(current))
850 return security_task_kill(t, info, sig, NULL);
854 * ptrace_trap_notify - schedule trap to notify ptracer
855 * @t: tracee wanting to notify tracer
857 * This function schedules sticky ptrace trap which is cleared on the next
858 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
861 * If @t is running, STOP trap will be taken. If trapped for STOP and
862 * ptracer is listening for events, tracee is woken up so that it can
863 * re-trap for the new event. If trapped otherwise, STOP trap will be
864 * eventually taken without returning to userland after the existing traps
865 * are finished by PTRACE_CONT.
868 * Must be called with @task->sighand->siglock held.
870 static void ptrace_trap_notify(struct task_struct *t)
872 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
873 assert_spin_locked(&t->sighand->siglock);
875 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
876 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
880 * Handle magic process-wide effects of stop/continue signals. Unlike
881 * the signal actions, these happen immediately at signal-generation
882 * time regardless of blocking, ignoring, or handling. This does the
883 * actual continuing for SIGCONT, but not the actual stopping for stop
884 * signals. The process stop is done as a signal action for SIG_DFL.
886 * Returns true if the signal should be actually delivered, otherwise
887 * it should be dropped.
889 static bool prepare_signal(int sig, struct task_struct *p, bool force)
891 struct signal_struct *signal = p->signal;
892 struct task_struct *t;
895 if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
896 if (!(signal->flags & SIGNAL_GROUP_EXIT))
897 return sig == SIGKILL;
899 * The process is in the middle of dying, nothing to do.
901 } else if (sig_kernel_stop(sig)) {
903 * This is a stop signal. Remove SIGCONT from all queues.
905 siginitset(&flush, sigmask(SIGCONT));
906 flush_sigqueue_mask(&flush, &signal->shared_pending);
907 for_each_thread(p, t)
908 flush_sigqueue_mask(&flush, &t->pending);
909 } else if (sig == SIGCONT) {
912 * Remove all stop signals from all queues, wake all threads.
914 siginitset(&flush, SIG_KERNEL_STOP_MASK);
915 flush_sigqueue_mask(&flush, &signal->shared_pending);
916 for_each_thread(p, t) {
917 flush_sigqueue_mask(&flush, &t->pending);
918 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
919 if (likely(!(t->ptrace & PT_SEIZED)))
920 wake_up_state(t, __TASK_STOPPED);
922 ptrace_trap_notify(t);
926 * Notify the parent with CLD_CONTINUED if we were stopped.
928 * If we were in the middle of a group stop, we pretend it
929 * was already finished, and then continued. Since SIGCHLD
930 * doesn't queue we report only CLD_STOPPED, as if the next
931 * CLD_CONTINUED was dropped.
934 if (signal->flags & SIGNAL_STOP_STOPPED)
935 why |= SIGNAL_CLD_CONTINUED;
936 else if (signal->group_stop_count)
937 why |= SIGNAL_CLD_STOPPED;
941 * The first thread which returns from do_signal_stop()
942 * will take ->siglock, notice SIGNAL_CLD_MASK, and
943 * notify its parent. See get_signal().
945 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
946 signal->group_stop_count = 0;
947 signal->group_exit_code = 0;
951 return !sig_ignored(p, sig, force);
955 * Test if P wants to take SIG. After we've checked all threads with this,
956 * it's equivalent to finding no threads not blocking SIG. Any threads not
957 * blocking SIG were ruled out because they are not running and already
958 * have pending signals. Such threads will dequeue from the shared queue
959 * as soon as they're available, so putting the signal on the shared queue
960 * will be equivalent to sending it to one such thread.
962 static inline bool wants_signal(int sig, struct task_struct *p)
964 if (sigismember(&p->blocked, sig))
967 if (p->flags & PF_EXITING)
973 if (task_is_stopped_or_traced(p))
976 return task_curr(p) || !signal_pending(p);
979 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
981 struct signal_struct *signal = p->signal;
982 struct task_struct *t;
985 * Now find a thread we can wake up to take the signal off the queue.
987 * If the main thread wants the signal, it gets first crack.
988 * Probably the least surprising to the average bear.
990 if (wants_signal(sig, p))
992 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
994 * There is just one thread and it does not need to be woken.
995 * It will dequeue unblocked signals before it runs again.
1000 * Otherwise try to find a suitable thread.
1002 t = signal->curr_target;
1003 while (!wants_signal(sig, t)) {
1005 if (t == signal->curr_target)
1007 * No thread needs to be woken.
1008 * Any eligible threads will see
1009 * the signal in the queue soon.
1013 signal->curr_target = t;
1017 * Found a killable thread. If the signal will be fatal,
1018 * then start taking the whole group down immediately.
1020 if (sig_fatal(p, sig) &&
1021 !(signal->flags & SIGNAL_GROUP_EXIT) &&
1022 !sigismember(&t->real_blocked, sig) &&
1023 (sig == SIGKILL || !p->ptrace)) {
1025 * This signal will be fatal to the whole group.
1027 if (!sig_kernel_coredump(sig)) {
1029 * Start a group exit and wake everybody up.
1030 * This way we don't have other threads
1031 * running and doing things after a slower
1032 * thread has the fatal signal pending.
1034 signal->flags = SIGNAL_GROUP_EXIT;
1035 signal->group_exit_code = sig;
1036 signal->group_stop_count = 0;
1039 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1040 sigaddset(&t->pending.signal, SIGKILL);
1041 signal_wake_up(t, 1);
1042 } while_each_thread(p, t);
1048 * The signal is already in the shared-pending queue.
1049 * Tell the chosen thread to wake up and dequeue it.
1051 signal_wake_up(t, sig == SIGKILL);
1055 static inline bool legacy_queue(struct sigpending *signals, int sig)
1057 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1060 static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1061 enum pid_type type, bool force)
1063 struct sigpending *pending;
1065 int override_rlimit;
1066 int ret = 0, result;
1068 assert_spin_locked(&t->sighand->siglock);
1070 result = TRACE_SIGNAL_IGNORED;
1071 if (!prepare_signal(sig, t, force))
1074 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1076 * Short-circuit ignored signals and support queuing
1077 * exactly one non-rt signal, so that we can get more
1078 * detailed information about the cause of the signal.
1080 result = TRACE_SIGNAL_ALREADY_PENDING;
1081 if (legacy_queue(pending, sig))
1084 result = TRACE_SIGNAL_DELIVERED;
1086 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1088 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1092 * Real-time signals must be queued if sent by sigqueue, or
1093 * some other real-time mechanism. It is implementation
1094 * defined whether kill() does so. We attempt to do so, on
1095 * the principle of least surprise, but since kill is not
1096 * allowed to fail with EAGAIN when low on memory we just
1097 * make sure at least one signal gets delivered and don't
1098 * pass on the info struct.
1101 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1103 override_rlimit = 0;
1105 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
1107 list_add_tail(&q->list, &pending->list);
1108 switch ((unsigned long) info) {
1109 case (unsigned long) SEND_SIG_NOINFO:
1110 clear_siginfo(&q->info);
1111 q->info.si_signo = sig;
1112 q->info.si_errno = 0;
1113 q->info.si_code = SI_USER;
1114 q->info.si_pid = task_tgid_nr_ns(current,
1115 task_active_pid_ns(t));
1118 from_kuid_munged(task_cred_xxx(t, user_ns),
1122 case (unsigned long) SEND_SIG_PRIV:
1123 clear_siginfo(&q->info);
1124 q->info.si_signo = sig;
1125 q->info.si_errno = 0;
1126 q->info.si_code = SI_KERNEL;
1131 copy_siginfo(&q->info, info);
1134 } else if (!is_si_special(info) &&
1135 sig >= SIGRTMIN && info->si_code != SI_USER) {
1137 * Queue overflow, abort. We may abort if the
1138 * signal was rt and sent by user using something
1139 * other than kill().
1141 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1146 * This is a silent loss of information. We still
1147 * send the signal, but the *info bits are lost.
1149 result = TRACE_SIGNAL_LOSE_INFO;
1153 signalfd_notify(t, sig);
1154 sigaddset(&pending->signal, sig);
1156 /* Let multiprocess signals appear after on-going forks */
1157 if (type > PIDTYPE_TGID) {
1158 struct multiprocess_signals *delayed;
1159 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1160 sigset_t *signal = &delayed->signal;
1161 /* Can't queue both a stop and a continue signal */
1163 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1164 else if (sig_kernel_stop(sig))
1165 sigdelset(signal, SIGCONT);
1166 sigaddset(signal, sig);
1170 complete_signal(sig, t, type);
1172 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1176 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1179 switch (siginfo_layout(info->si_signo, info->si_code)) {
1188 case SIL_FAULT_MCEERR:
1189 case SIL_FAULT_BNDERR:
1190 case SIL_FAULT_PKUERR:
1198 static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
1201 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1204 if (info == SEND_SIG_NOINFO) {
1205 /* Force if sent from an ancestor pid namespace */
1206 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1207 } else if (info == SEND_SIG_PRIV) {
1208 /* Don't ignore kernel generated signals */
1210 } else if (has_si_pid_and_uid(info)) {
1211 /* SIGKILL and SIGSTOP is special or has ids */
1212 struct user_namespace *t_user_ns;
1215 t_user_ns = task_cred_xxx(t, user_ns);
1216 if (current_user_ns() != t_user_ns) {
1217 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1218 info->si_uid = from_kuid_munged(t_user_ns, uid);
1222 /* A kernel generated signal? */
1223 force = (info->si_code == SI_KERNEL);
1225 /* From an ancestor pid namespace? */
1226 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1231 return __send_signal(sig, info, t, type, force);
1234 static void print_fatal_signal(int signr)
1236 struct pt_regs *regs = signal_pt_regs();
1237 pr_info("potentially unexpected fatal signal %d.\n", signr);
1239 #if defined(__i386__) && !defined(__arch_um__)
1240 pr_info("code at %08lx: ", regs->ip);
1243 for (i = 0; i < 16; i++) {
1246 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1248 pr_cont("%02x ", insn);
1258 static int __init setup_print_fatal_signals(char *str)
1260 get_option (&str, &print_fatal_signals);
1265 __setup("print-fatal-signals=", setup_print_fatal_signals);
1268 __group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1270 return send_signal(sig, info, p, PIDTYPE_TGID);
1273 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1276 unsigned long flags;
1279 if (lock_task_sighand(p, &flags)) {
1280 ret = send_signal(sig, info, p, type);
1281 unlock_task_sighand(p, &flags);
1288 * Force a signal that the process can't ignore: if necessary
1289 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1291 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1292 * since we do not want to have a signal handler that was blocked
1293 * be invoked when user space had explicitly blocked it.
1295 * We don't want to have recursive SIGSEGV's etc, for example,
1296 * that is why we also clear SIGNAL_UNKILLABLE.
1299 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t)
1301 unsigned long int flags;
1302 int ret, blocked, ignored;
1303 struct k_sigaction *action;
1304 int sig = info->si_signo;
1306 spin_lock_irqsave(&t->sighand->siglock, flags);
1307 action = &t->sighand->action[sig-1];
1308 ignored = action->sa.sa_handler == SIG_IGN;
1309 blocked = sigismember(&t->blocked, sig);
1310 if (blocked || ignored) {
1311 action->sa.sa_handler = SIG_DFL;
1313 sigdelset(&t->blocked, sig);
1314 recalc_sigpending_and_wake(t);
1318 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1319 * debugging to leave init killable.
1321 if (action->sa.sa_handler == SIG_DFL && !t->ptrace)
1322 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1323 ret = send_signal(sig, info, t, PIDTYPE_PID);
1324 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1329 int force_sig_info(struct kernel_siginfo *info)
1331 return force_sig_info_to_task(info, current);
1335 * Nuke all other threads in the group.
1337 int zap_other_threads(struct task_struct *p)
1339 struct task_struct *t = p;
1342 p->signal->group_stop_count = 0;
1344 while_each_thread(p, t) {
1345 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1348 /* Don't bother with already dead threads */
1351 sigaddset(&t->pending.signal, SIGKILL);
1352 signal_wake_up(t, 1);
1358 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1359 unsigned long *flags)
1361 struct sighand_struct *sighand;
1365 sighand = rcu_dereference(tsk->sighand);
1366 if (unlikely(sighand == NULL))
1370 * This sighand can be already freed and even reused, but
1371 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1372 * initializes ->siglock: this slab can't go away, it has
1373 * the same object type, ->siglock can't be reinitialized.
1375 * We need to ensure that tsk->sighand is still the same
1376 * after we take the lock, we can race with de_thread() or
1377 * __exit_signal(). In the latter case the next iteration
1378 * must see ->sighand == NULL.
1380 spin_lock_irqsave(&sighand->siglock, *flags);
1381 if (likely(sighand == tsk->sighand))
1383 spin_unlock_irqrestore(&sighand->siglock, *flags);
1391 * send signal info to all the members of a group
1393 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1394 struct task_struct *p, enum pid_type type)
1399 ret = check_kill_permission(sig, info, p);
1403 ret = do_send_sig_info(sig, info, p, type);
1409 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1410 * control characters do (^C, ^Z etc)
1411 * - the caller must hold at least a readlock on tasklist_lock
1413 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1415 struct task_struct *p = NULL;
1416 int retval, success;
1420 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1421 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1424 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1425 return success ? 0 : retval;
1428 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1431 struct task_struct *p;
1435 p = pid_task(pid, PIDTYPE_PID);
1437 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1439 if (likely(!p || error != -ESRCH))
1443 * The task was unhashed in between, try again. If it
1444 * is dead, pid_task() will return NULL, if we race with
1445 * de_thread() it will find the new leader.
1450 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1454 error = kill_pid_info(sig, info, find_vpid(pid));
1459 static inline bool kill_as_cred_perm(const struct cred *cred,
1460 struct task_struct *target)
1462 const struct cred *pcred = __task_cred(target);
1464 return uid_eq(cred->euid, pcred->suid) ||
1465 uid_eq(cred->euid, pcred->uid) ||
1466 uid_eq(cred->uid, pcred->suid) ||
1467 uid_eq(cred->uid, pcred->uid);
1471 * The usb asyncio usage of siginfo is wrong. The glibc support
1472 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1473 * AKA after the generic fields:
1474 * kernel_pid_t si_pid;
1475 * kernel_uid32_t si_uid;
1476 * sigval_t si_value;
1478 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1479 * after the generic fields is:
1480 * void __user *si_addr;
1482 * This is a practical problem when there is a 64bit big endian kernel
1483 * and a 32bit userspace. As the 32bit address will encoded in the low
1484 * 32bits of the pointer. Those low 32bits will be stored at higher
1485 * address than appear in a 32 bit pointer. So userspace will not
1486 * see the address it was expecting for it's completions.
1488 * There is nothing in the encoding that can allow
1489 * copy_siginfo_to_user32 to detect this confusion of formats, so
1490 * handle this by requiring the caller of kill_pid_usb_asyncio to
1491 * notice when this situration takes place and to store the 32bit
1492 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1495 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1496 struct pid *pid, const struct cred *cred)
1498 struct kernel_siginfo info;
1499 struct task_struct *p;
1500 unsigned long flags;
1503 clear_siginfo(&info);
1504 info.si_signo = sig;
1505 info.si_errno = errno;
1506 info.si_code = SI_ASYNCIO;
1507 *((sigval_t *)&info.si_pid) = addr;
1509 if (!valid_signal(sig))
1513 p = pid_task(pid, PIDTYPE_PID);
1518 if (!kill_as_cred_perm(cred, p)) {
1522 ret = security_task_kill(p, &info, sig, cred);
1527 if (lock_task_sighand(p, &flags)) {
1528 ret = __send_signal(sig, &info, p, PIDTYPE_TGID, false);
1529 unlock_task_sighand(p, &flags);
1537 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1540 * kill_something_info() interprets pid in interesting ways just like kill(2).
1542 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1543 * is probably wrong. Should make it like BSD or SYSV.
1546 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1552 ret = kill_pid_info(sig, info, find_vpid(pid));
1557 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1561 read_lock(&tasklist_lock);
1563 ret = __kill_pgrp_info(sig, info,
1564 pid ? find_vpid(-pid) : task_pgrp(current));
1566 int retval = 0, count = 0;
1567 struct task_struct * p;
1569 for_each_process(p) {
1570 if (task_pid_vnr(p) > 1 &&
1571 !same_thread_group(p, current)) {
1572 int err = group_send_sig_info(sig, info, p,
1579 ret = count ? retval : -ESRCH;
1581 read_unlock(&tasklist_lock);
1587 * These are for backward compatibility with the rest of the kernel source.
1590 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1593 * Make sure legacy kernel users don't send in bad values
1594 * (normal paths check this in check_kill_permission).
1596 if (!valid_signal(sig))
1599 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1601 EXPORT_SYMBOL(send_sig_info);
1603 #define __si_special(priv) \
1604 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1607 send_sig(int sig, struct task_struct *p, int priv)
1609 return send_sig_info(sig, __si_special(priv), p);
1611 EXPORT_SYMBOL(send_sig);
1613 void force_sig(int sig)
1615 struct kernel_siginfo info;
1617 clear_siginfo(&info);
1618 info.si_signo = sig;
1620 info.si_code = SI_KERNEL;
1623 force_sig_info(&info);
1625 EXPORT_SYMBOL(force_sig);
1628 * When things go south during signal handling, we
1629 * will force a SIGSEGV. And if the signal that caused
1630 * the problem was already a SIGSEGV, we'll want to
1631 * make sure we don't even try to deliver the signal..
1633 void force_sigsegv(int sig)
1635 struct task_struct *p = current;
1637 if (sig == SIGSEGV) {
1638 unsigned long flags;
1639 spin_lock_irqsave(&p->sighand->siglock, flags);
1640 p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
1641 spin_unlock_irqrestore(&p->sighand->siglock, flags);
1646 int force_sig_fault_to_task(int sig, int code, void __user *addr
1647 ___ARCH_SI_TRAPNO(int trapno)
1648 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1649 , struct task_struct *t)
1651 struct kernel_siginfo info;
1653 clear_siginfo(&info);
1654 info.si_signo = sig;
1656 info.si_code = code;
1657 info.si_addr = addr;
1658 #ifdef __ARCH_SI_TRAPNO
1659 info.si_trapno = trapno;
1663 info.si_flags = flags;
1666 return force_sig_info_to_task(&info, t);
1669 int force_sig_fault(int sig, int code, void __user *addr
1670 ___ARCH_SI_TRAPNO(int trapno)
1671 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1673 return force_sig_fault_to_task(sig, code, addr
1674 ___ARCH_SI_TRAPNO(trapno)
1675 ___ARCH_SI_IA64(imm, flags, isr), current);
1678 int send_sig_fault(int sig, int code, void __user *addr
1679 ___ARCH_SI_TRAPNO(int trapno)
1680 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1681 , struct task_struct *t)
1683 struct kernel_siginfo info;
1685 clear_siginfo(&info);
1686 info.si_signo = sig;
1688 info.si_code = code;
1689 info.si_addr = addr;
1690 #ifdef __ARCH_SI_TRAPNO
1691 info.si_trapno = trapno;
1695 info.si_flags = flags;
1698 return send_sig_info(info.si_signo, &info, t);
1701 int force_sig_mceerr(int code, void __user *addr, short lsb)
1703 struct kernel_siginfo info;
1705 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1706 clear_siginfo(&info);
1707 info.si_signo = SIGBUS;
1709 info.si_code = code;
1710 info.si_addr = addr;
1711 info.si_addr_lsb = lsb;
1712 return force_sig_info(&info);
1715 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1717 struct kernel_siginfo info;
1719 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1720 clear_siginfo(&info);
1721 info.si_signo = SIGBUS;
1723 info.si_code = code;
1724 info.si_addr = addr;
1725 info.si_addr_lsb = lsb;
1726 return send_sig_info(info.si_signo, &info, t);
1728 EXPORT_SYMBOL(send_sig_mceerr);
1730 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1732 struct kernel_siginfo info;
1734 clear_siginfo(&info);
1735 info.si_signo = SIGSEGV;
1737 info.si_code = SEGV_BNDERR;
1738 info.si_addr = addr;
1739 info.si_lower = lower;
1740 info.si_upper = upper;
1741 return force_sig_info(&info);
1745 int force_sig_pkuerr(void __user *addr, u32 pkey)
1747 struct kernel_siginfo info;
1749 clear_siginfo(&info);
1750 info.si_signo = SIGSEGV;
1752 info.si_code = SEGV_PKUERR;
1753 info.si_addr = addr;
1754 info.si_pkey = pkey;
1755 return force_sig_info(&info);
1759 /* For the crazy architectures that include trap information in
1760 * the errno field, instead of an actual errno value.
1762 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1764 struct kernel_siginfo info;
1766 clear_siginfo(&info);
1767 info.si_signo = SIGTRAP;
1768 info.si_errno = errno;
1769 info.si_code = TRAP_HWBKPT;
1770 info.si_addr = addr;
1771 return force_sig_info(&info);
1774 int kill_pgrp(struct pid *pid, int sig, int priv)
1778 read_lock(&tasklist_lock);
1779 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1780 read_unlock(&tasklist_lock);
1784 EXPORT_SYMBOL(kill_pgrp);
1786 int kill_pid(struct pid *pid, int sig, int priv)
1788 return kill_pid_info(sig, __si_special(priv), pid);
1790 EXPORT_SYMBOL(kill_pid);
1793 * These functions support sending signals using preallocated sigqueue
1794 * structures. This is needed "because realtime applications cannot
1795 * afford to lose notifications of asynchronous events, like timer
1796 * expirations or I/O completions". In the case of POSIX Timers
1797 * we allocate the sigqueue structure from the timer_create. If this
1798 * allocation fails we are able to report the failure to the application
1799 * with an EAGAIN error.
1801 struct sigqueue *sigqueue_alloc(void)
1803 struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
1806 q->flags |= SIGQUEUE_PREALLOC;
1811 void sigqueue_free(struct sigqueue *q)
1813 unsigned long flags;
1814 spinlock_t *lock = ¤t->sighand->siglock;
1816 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1818 * We must hold ->siglock while testing q->list
1819 * to serialize with collect_signal() or with
1820 * __exit_signal()->flush_sigqueue().
1822 spin_lock_irqsave(lock, flags);
1823 q->flags &= ~SIGQUEUE_PREALLOC;
1825 * If it is queued it will be freed when dequeued,
1826 * like the "regular" sigqueue.
1828 if (!list_empty(&q->list))
1830 spin_unlock_irqrestore(lock, flags);
1836 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1838 int sig = q->info.si_signo;
1839 struct sigpending *pending;
1840 struct task_struct *t;
1841 unsigned long flags;
1844 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1848 t = pid_task(pid, type);
1849 if (!t || !likely(lock_task_sighand(t, &flags)))
1852 ret = 1; /* the signal is ignored */
1853 result = TRACE_SIGNAL_IGNORED;
1854 if (!prepare_signal(sig, t, false))
1858 if (unlikely(!list_empty(&q->list))) {
1860 * If an SI_TIMER entry is already queue just increment
1861 * the overrun count.
1863 BUG_ON(q->info.si_code != SI_TIMER);
1864 q->info.si_overrun++;
1865 result = TRACE_SIGNAL_ALREADY_PENDING;
1868 q->info.si_overrun = 0;
1870 signalfd_notify(t, sig);
1871 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1872 list_add_tail(&q->list, &pending->list);
1873 sigaddset(&pending->signal, sig);
1874 complete_signal(sig, t, type);
1875 result = TRACE_SIGNAL_DELIVERED;
1877 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
1878 unlock_task_sighand(t, &flags);
1885 * Let a parent know about the death of a child.
1886 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1888 * Returns true if our parent ignored us and so we've switched to
1891 bool do_notify_parent(struct task_struct *tsk, int sig)
1893 struct kernel_siginfo info;
1894 unsigned long flags;
1895 struct sighand_struct *psig;
1896 bool autoreap = false;
1901 /* do_notify_parent_cldstop should have been called instead. */
1902 BUG_ON(task_is_stopped_or_traced(tsk));
1904 BUG_ON(!tsk->ptrace &&
1905 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
1907 if (sig != SIGCHLD) {
1909 * This is only possible if parent == real_parent.
1910 * Check if it has changed security domain.
1912 if (tsk->parent_exec_id != tsk->parent->self_exec_id)
1916 clear_siginfo(&info);
1917 info.si_signo = sig;
1920 * We are under tasklist_lock here so our parent is tied to
1921 * us and cannot change.
1923 * task_active_pid_ns will always return the same pid namespace
1924 * until a task passes through release_task.
1926 * write_lock() currently calls preempt_disable() which is the
1927 * same as rcu_read_lock(), but according to Oleg, this is not
1928 * correct to rely on this
1931 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
1932 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
1936 task_cputime(tsk, &utime, &stime);
1937 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
1938 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
1940 info.si_status = tsk->exit_code & 0x7f;
1941 if (tsk->exit_code & 0x80)
1942 info.si_code = CLD_DUMPED;
1943 else if (tsk->exit_code & 0x7f)
1944 info.si_code = CLD_KILLED;
1946 info.si_code = CLD_EXITED;
1947 info.si_status = tsk->exit_code >> 8;
1950 psig = tsk->parent->sighand;
1951 spin_lock_irqsave(&psig->siglock, flags);
1952 if (!tsk->ptrace && sig == SIGCHLD &&
1953 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
1954 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
1956 * We are exiting and our parent doesn't care. POSIX.1
1957 * defines special semantics for setting SIGCHLD to SIG_IGN
1958 * or setting the SA_NOCLDWAIT flag: we should be reaped
1959 * automatically and not left for our parent's wait4 call.
1960 * Rather than having the parent do it as a magic kind of
1961 * signal handler, we just set this to tell do_exit that we
1962 * can be cleaned up without becoming a zombie. Note that
1963 * we still call __wake_up_parent in this case, because a
1964 * blocked sys_wait4 might now return -ECHILD.
1966 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1967 * is implementation-defined: we do (if you don't want
1968 * it, just use SIG_IGN instead).
1971 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
1974 if (valid_signal(sig) && sig)
1975 __group_send_sig_info(sig, &info, tsk->parent);
1976 __wake_up_parent(tsk, tsk->parent);
1977 spin_unlock_irqrestore(&psig->siglock, flags);
1983 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1984 * @tsk: task reporting the state change
1985 * @for_ptracer: the notification is for ptracer
1986 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1988 * Notify @tsk's parent that the stopped/continued state has changed. If
1989 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1990 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1993 * Must be called with tasklist_lock at least read locked.
1995 static void do_notify_parent_cldstop(struct task_struct *tsk,
1996 bool for_ptracer, int why)
1998 struct kernel_siginfo info;
1999 unsigned long flags;
2000 struct task_struct *parent;
2001 struct sighand_struct *sighand;
2005 parent = tsk->parent;
2007 tsk = tsk->group_leader;
2008 parent = tsk->real_parent;
2011 clear_siginfo(&info);
2012 info.si_signo = SIGCHLD;
2015 * see comment in do_notify_parent() about the following 4 lines
2018 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2019 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2022 task_cputime(tsk, &utime, &stime);
2023 info.si_utime = nsec_to_clock_t(utime);
2024 info.si_stime = nsec_to_clock_t(stime);
2029 info.si_status = SIGCONT;
2032 info.si_status = tsk->signal->group_exit_code & 0x7f;
2035 info.si_status = tsk->exit_code & 0x7f;
2041 sighand = parent->sighand;
2042 spin_lock_irqsave(&sighand->siglock, flags);
2043 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2044 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2045 __group_send_sig_info(SIGCHLD, &info, parent);
2047 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2049 __wake_up_parent(tsk, parent);
2050 spin_unlock_irqrestore(&sighand->siglock, flags);
2053 static inline bool may_ptrace_stop(void)
2055 if (!likely(current->ptrace))
2058 * Are we in the middle of do_coredump?
2059 * If so and our tracer is also part of the coredump stopping
2060 * is a deadlock situation, and pointless because our tracer
2061 * is dead so don't allow us to stop.
2062 * If SIGKILL was already sent before the caller unlocked
2063 * ->siglock we must see ->core_state != NULL. Otherwise it
2064 * is safe to enter schedule().
2066 * This is almost outdated, a task with the pending SIGKILL can't
2067 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2068 * after SIGKILL was already dequeued.
2070 if (unlikely(current->mm->core_state) &&
2071 unlikely(current->mm == current->parent->mm))
2078 * Return non-zero if there is a SIGKILL that should be waking us up.
2079 * Called with the siglock held.
2081 static bool sigkill_pending(struct task_struct *tsk)
2083 return sigismember(&tsk->pending.signal, SIGKILL) ||
2084 sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
2088 * This must be called with current->sighand->siglock held.
2090 * This should be the path for all ptrace stops.
2091 * We always set current->last_siginfo while stopped here.
2092 * That makes it a way to test a stopped process for
2093 * being ptrace-stopped vs being job-control-stopped.
2095 * If we actually decide not to stop at all because the tracer
2096 * is gone, we keep current->exit_code unless clear_code.
2098 static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
2099 __releases(¤t->sighand->siglock)
2100 __acquires(¤t->sighand->siglock)
2102 bool gstop_done = false;
2104 if (arch_ptrace_stop_needed(exit_code, info)) {
2106 * The arch code has something special to do before a
2107 * ptrace stop. This is allowed to block, e.g. for faults
2108 * on user stack pages. We can't keep the siglock while
2109 * calling arch_ptrace_stop, so we must release it now.
2110 * To preserve proper semantics, we must do this before
2111 * any signal bookkeeping like checking group_stop_count.
2112 * Meanwhile, a SIGKILL could come in before we retake the
2113 * siglock. That must prevent us from sleeping in TASK_TRACED.
2114 * So after regaining the lock, we must check for SIGKILL.
2116 spin_unlock_irq(¤t->sighand->siglock);
2117 arch_ptrace_stop(exit_code, info);
2118 spin_lock_irq(¤t->sighand->siglock);
2119 if (sigkill_pending(current))
2123 set_special_state(TASK_TRACED);
2126 * We're committing to trapping. TRACED should be visible before
2127 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2128 * Also, transition to TRACED and updates to ->jobctl should be
2129 * atomic with respect to siglock and should be done after the arch
2130 * hook as siglock is released and regrabbed across it.
2135 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2137 * set_current_state() smp_wmb();
2139 * wait_task_stopped()
2140 * task_stopped_code()
2141 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2145 current->last_siginfo = info;
2146 current->exit_code = exit_code;
2149 * If @why is CLD_STOPPED, we're trapping to participate in a group
2150 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2151 * across siglock relocks since INTERRUPT was scheduled, PENDING
2152 * could be clear now. We act as if SIGCONT is received after
2153 * TASK_TRACED is entered - ignore it.
2155 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2156 gstop_done = task_participate_group_stop(current);
2158 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2159 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2160 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2161 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2163 /* entering a trap, clear TRAPPING */
2164 task_clear_jobctl_trapping(current);
2166 spin_unlock_irq(¤t->sighand->siglock);
2167 read_lock(&tasklist_lock);
2168 if (may_ptrace_stop()) {
2170 * Notify parents of the stop.
2172 * While ptraced, there are two parents - the ptracer and
2173 * the real_parent of the group_leader. The ptracer should
2174 * know about every stop while the real parent is only
2175 * interested in the completion of group stop. The states
2176 * for the two don't interact with each other. Notify
2177 * separately unless they're gonna be duplicates.
2179 do_notify_parent_cldstop(current, true, why);
2180 if (gstop_done && ptrace_reparented(current))
2181 do_notify_parent_cldstop(current, false, why);
2184 * Don't want to allow preemption here, because
2185 * sys_ptrace() needs this task to be inactive.
2187 * XXX: implement read_unlock_no_resched().
2190 read_unlock(&tasklist_lock);
2191 preempt_enable_no_resched();
2192 cgroup_enter_frozen();
2193 freezable_schedule();
2194 cgroup_leave_frozen(true);
2197 * By the time we got the lock, our tracer went away.
2198 * Don't drop the lock yet, another tracer may come.
2200 * If @gstop_done, the ptracer went away between group stop
2201 * completion and here. During detach, it would have set
2202 * JOBCTL_STOP_PENDING on us and we'll re-enter
2203 * TASK_STOPPED in do_signal_stop() on return, so notifying
2204 * the real parent of the group stop completion is enough.
2207 do_notify_parent_cldstop(current, false, why);
2209 /* tasklist protects us from ptrace_freeze_traced() */
2210 __set_current_state(TASK_RUNNING);
2212 current->exit_code = 0;
2213 read_unlock(&tasklist_lock);
2217 * We are back. Now reacquire the siglock before touching
2218 * last_siginfo, so that we are sure to have synchronized with
2219 * any signal-sending on another CPU that wants to examine it.
2221 spin_lock_irq(¤t->sighand->siglock);
2222 current->last_siginfo = NULL;
2224 /* LISTENING can be set only during STOP traps, clear it */
2225 current->jobctl &= ~JOBCTL_LISTENING;
2228 * Queued signals ignored us while we were stopped for tracing.
2229 * So check for any that we should take before resuming user mode.
2230 * This sets TIF_SIGPENDING, but never clears it.
2232 recalc_sigpending_tsk(current);
2235 static void ptrace_do_notify(int signr, int exit_code, int why)
2237 kernel_siginfo_t info;
2239 clear_siginfo(&info);
2240 info.si_signo = signr;
2241 info.si_code = exit_code;
2242 info.si_pid = task_pid_vnr(current);
2243 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2245 /* Let the debugger run. */
2246 ptrace_stop(exit_code, why, 1, &info);
2249 void ptrace_notify(int exit_code)
2251 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2252 if (unlikely(current->task_works))
2255 spin_lock_irq(¤t->sighand->siglock);
2256 ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
2257 spin_unlock_irq(¤t->sighand->siglock);
2261 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2262 * @signr: signr causing group stop if initiating
2264 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2265 * and participate in it. If already set, participate in the existing
2266 * group stop. If participated in a group stop (and thus slept), %true is
2267 * returned with siglock released.
2269 * If ptraced, this function doesn't handle stop itself. Instead,
2270 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2271 * untouched. The caller must ensure that INTERRUPT trap handling takes
2272 * places afterwards.
2275 * Must be called with @current->sighand->siglock held, which is released
2279 * %false if group stop is already cancelled or ptrace trap is scheduled.
2280 * %true if participated in group stop.
2282 static bool do_signal_stop(int signr)
2283 __releases(¤t->sighand->siglock)
2285 struct signal_struct *sig = current->signal;
2287 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2288 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2289 struct task_struct *t;
2291 /* signr will be recorded in task->jobctl for retries */
2292 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2294 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2295 unlikely(signal_group_exit(sig)))
2298 * There is no group stop already in progress. We must
2301 * While ptraced, a task may be resumed while group stop is
2302 * still in effect and then receive a stop signal and
2303 * initiate another group stop. This deviates from the
2304 * usual behavior as two consecutive stop signals can't
2305 * cause two group stops when !ptraced. That is why we
2306 * also check !task_is_stopped(t) below.
2308 * The condition can be distinguished by testing whether
2309 * SIGNAL_STOP_STOPPED is already set. Don't generate
2310 * group_exit_code in such case.
2312 * This is not necessary for SIGNAL_STOP_CONTINUED because
2313 * an intervening stop signal is required to cause two
2314 * continued events regardless of ptrace.
2316 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2317 sig->group_exit_code = signr;
2319 sig->group_stop_count = 0;
2321 if (task_set_jobctl_pending(current, signr | gstop))
2322 sig->group_stop_count++;
2325 while_each_thread(current, t) {
2327 * Setting state to TASK_STOPPED for a group
2328 * stop is always done with the siglock held,
2329 * so this check has no races.
2331 if (!task_is_stopped(t) &&
2332 task_set_jobctl_pending(t, signr | gstop)) {
2333 sig->group_stop_count++;
2334 if (likely(!(t->ptrace & PT_SEIZED)))
2335 signal_wake_up(t, 0);
2337 ptrace_trap_notify(t);
2342 if (likely(!current->ptrace)) {
2346 * If there are no other threads in the group, or if there
2347 * is a group stop in progress and we are the last to stop,
2348 * report to the parent.
2350 if (task_participate_group_stop(current))
2351 notify = CLD_STOPPED;
2353 set_special_state(TASK_STOPPED);
2354 spin_unlock_irq(¤t->sighand->siglock);
2357 * Notify the parent of the group stop completion. Because
2358 * we're not holding either the siglock or tasklist_lock
2359 * here, ptracer may attach inbetween; however, this is for
2360 * group stop and should always be delivered to the real
2361 * parent of the group leader. The new ptracer will get
2362 * its notification when this task transitions into
2366 read_lock(&tasklist_lock);
2367 do_notify_parent_cldstop(current, false, notify);
2368 read_unlock(&tasklist_lock);
2371 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2372 cgroup_enter_frozen();
2373 freezable_schedule();
2377 * While ptraced, group stop is handled by STOP trap.
2378 * Schedule it and let the caller deal with it.
2380 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2386 * do_jobctl_trap - take care of ptrace jobctl traps
2388 * When PT_SEIZED, it's used for both group stop and explicit
2389 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2390 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2391 * the stop signal; otherwise, %SIGTRAP.
2393 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2394 * number as exit_code and no siginfo.
2397 * Must be called with @current->sighand->siglock held, which may be
2398 * released and re-acquired before returning with intervening sleep.
2400 static void do_jobctl_trap(void)
2402 struct signal_struct *signal = current->signal;
2403 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2405 if (current->ptrace & PT_SEIZED) {
2406 if (!signal->group_stop_count &&
2407 !(signal->flags & SIGNAL_STOP_STOPPED))
2409 WARN_ON_ONCE(!signr);
2410 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2413 WARN_ON_ONCE(!signr);
2414 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2415 current->exit_code = 0;
2420 * do_freezer_trap - handle the freezer jobctl trap
2422 * Puts the task into frozen state, if only the task is not about to quit.
2423 * In this case it drops JOBCTL_TRAP_FREEZE.
2426 * Must be called with @current->sighand->siglock held,
2427 * which is always released before returning.
2429 static void do_freezer_trap(void)
2430 __releases(¤t->sighand->siglock)
2433 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2434 * let's make another loop to give it a chance to be handled.
2435 * In any case, we'll return back.
2437 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2438 JOBCTL_TRAP_FREEZE) {
2439 spin_unlock_irq(¤t->sighand->siglock);
2444 * Now we're sure that there is no pending fatal signal and no
2445 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2446 * immediately (if there is a non-fatal signal pending), and
2447 * put the task into sleep.
2449 __set_current_state(TASK_INTERRUPTIBLE);
2450 clear_thread_flag(TIF_SIGPENDING);
2451 spin_unlock_irq(¤t->sighand->siglock);
2452 cgroup_enter_frozen();
2453 freezable_schedule();
2456 static int ptrace_signal(int signr, kernel_siginfo_t *info)
2459 * We do not check sig_kernel_stop(signr) but set this marker
2460 * unconditionally because we do not know whether debugger will
2461 * change signr. This flag has no meaning unless we are going
2462 * to stop after return from ptrace_stop(). In this case it will
2463 * be checked in do_signal_stop(), we should only stop if it was
2464 * not cleared by SIGCONT while we were sleeping. See also the
2465 * comment in dequeue_signal().
2467 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2468 ptrace_stop(signr, CLD_TRAPPED, 0, info);
2470 /* We're back. Did the debugger cancel the sig? */
2471 signr = current->exit_code;
2475 current->exit_code = 0;
2478 * Update the siginfo structure if the signal has
2479 * changed. If the debugger wanted something
2480 * specific in the siginfo structure then it should
2481 * have updated *info via PTRACE_SETSIGINFO.
2483 if (signr != info->si_signo) {
2484 clear_siginfo(info);
2485 info->si_signo = signr;
2487 info->si_code = SI_USER;
2489 info->si_pid = task_pid_vnr(current->parent);
2490 info->si_uid = from_kuid_munged(current_user_ns(),
2491 task_uid(current->parent));
2495 /* If the (new) signal is now blocked, requeue it. */
2496 if (sigismember(¤t->blocked, signr)) {
2497 send_signal(signr, info, current, PIDTYPE_PID);
2504 bool get_signal(struct ksignal *ksig)
2506 struct sighand_struct *sighand = current->sighand;
2507 struct signal_struct *signal = current->signal;
2510 if (unlikely(current->task_works))
2513 if (unlikely(uprobe_deny_signal()))
2517 * Do this once, we can't return to user-mode if freezing() == T.
2518 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2519 * thus do not need another check after return.
2524 spin_lock_irq(&sighand->siglock);
2526 * Every stopped thread goes here after wakeup. Check to see if
2527 * we should notify the parent, prepare_signal(SIGCONT) encodes
2528 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2530 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2533 if (signal->flags & SIGNAL_CLD_CONTINUED)
2534 why = CLD_CONTINUED;
2538 signal->flags &= ~SIGNAL_CLD_MASK;
2540 spin_unlock_irq(&sighand->siglock);
2543 * Notify the parent that we're continuing. This event is
2544 * always per-process and doesn't make whole lot of sense
2545 * for ptracers, who shouldn't consume the state via
2546 * wait(2) either, but, for backward compatibility, notify
2547 * the ptracer of the group leader too unless it's gonna be
2550 read_lock(&tasklist_lock);
2551 do_notify_parent_cldstop(current, false, why);
2553 if (ptrace_reparented(current->group_leader))
2554 do_notify_parent_cldstop(current->group_leader,
2556 read_unlock(&tasklist_lock);
2561 /* Has this task already been marked for death? */
2562 if (signal_group_exit(signal)) {
2563 ksig->info.si_signo = signr = SIGKILL;
2564 sigdelset(¤t->pending.signal, SIGKILL);
2565 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2566 &sighand->action[SIGKILL - 1]);
2567 recalc_sigpending();
2572 struct k_sigaction *ka;
2574 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2578 if (unlikely(current->jobctl &
2579 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2580 if (current->jobctl & JOBCTL_TRAP_MASK) {
2582 spin_unlock_irq(&sighand->siglock);
2583 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2590 * If the task is leaving the frozen state, let's update
2591 * cgroup counters and reset the frozen bit.
2593 if (unlikely(cgroup_task_frozen(current))) {
2594 spin_unlock_irq(&sighand->siglock);
2595 cgroup_leave_frozen(false);
2600 * Signals generated by the execution of an instruction
2601 * need to be delivered before any other pending signals
2602 * so that the instruction pointer in the signal stack
2603 * frame points to the faulting instruction.
2605 signr = dequeue_synchronous_signal(&ksig->info);
2607 signr = dequeue_signal(current, ¤t->blocked, &ksig->info);
2610 break; /* will return 0 */
2612 if (unlikely(current->ptrace) && signr != SIGKILL) {
2613 signr = ptrace_signal(signr, &ksig->info);
2618 ka = &sighand->action[signr-1];
2620 /* Trace actually delivered signals. */
2621 trace_signal_deliver(signr, &ksig->info, ka);
2623 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2625 if (ka->sa.sa_handler != SIG_DFL) {
2626 /* Run the handler. */
2629 if (ka->sa.sa_flags & SA_ONESHOT)
2630 ka->sa.sa_handler = SIG_DFL;
2632 break; /* will return non-zero "signr" value */
2636 * Now we are doing the default action for this signal.
2638 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2642 * Global init gets no signals it doesn't want.
2643 * Container-init gets no signals it doesn't want from same
2646 * Note that if global/container-init sees a sig_kernel_only()
2647 * signal here, the signal must have been generated internally
2648 * or must have come from an ancestor namespace. In either
2649 * case, the signal cannot be dropped.
2651 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2652 !sig_kernel_only(signr))
2655 if (sig_kernel_stop(signr)) {
2657 * The default action is to stop all threads in
2658 * the thread group. The job control signals
2659 * do nothing in an orphaned pgrp, but SIGSTOP
2660 * always works. Note that siglock needs to be
2661 * dropped during the call to is_orphaned_pgrp()
2662 * because of lock ordering with tasklist_lock.
2663 * This allows an intervening SIGCONT to be posted.
2664 * We need to check for that and bail out if necessary.
2666 if (signr != SIGSTOP) {
2667 spin_unlock_irq(&sighand->siglock);
2669 /* signals can be posted during this window */
2671 if (is_current_pgrp_orphaned())
2674 spin_lock_irq(&sighand->siglock);
2677 if (likely(do_signal_stop(ksig->info.si_signo))) {
2678 /* It released the siglock. */
2683 * We didn't actually stop, due to a race
2684 * with SIGCONT or something like that.
2690 spin_unlock_irq(&sighand->siglock);
2691 if (unlikely(cgroup_task_frozen(current)))
2692 cgroup_leave_frozen(true);
2695 * Anything else is fatal, maybe with a core dump.
2697 current->flags |= PF_SIGNALED;
2699 if (sig_kernel_coredump(signr)) {
2700 if (print_fatal_signals)
2701 print_fatal_signal(ksig->info.si_signo);
2702 proc_coredump_connector(current);
2704 * If it was able to dump core, this kills all
2705 * other threads in the group and synchronizes with
2706 * their demise. If we lost the race with another
2707 * thread getting here, it set group_exit_code
2708 * first and our do_group_exit call below will use
2709 * that value and ignore the one we pass it.
2711 do_coredump(&ksig->info);
2715 * Death signals, no core dump.
2717 do_group_exit(ksig->info.si_signo);
2720 spin_unlock_irq(&sighand->siglock);
2723 return ksig->sig > 0;
2727 * signal_delivered -
2728 * @ksig: kernel signal struct
2729 * @stepping: nonzero if debugger single-step or block-step in use
2731 * This function should be called when a signal has successfully been
2732 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2733 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2734 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2736 static void signal_delivered(struct ksignal *ksig, int stepping)
2740 /* A signal was successfully delivered, and the
2741 saved sigmask was stored on the signal frame,
2742 and will be restored by sigreturn. So we can
2743 simply clear the restore sigmask flag. */
2744 clear_restore_sigmask();
2746 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2747 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2748 sigaddset(&blocked, ksig->sig);
2749 set_current_blocked(&blocked);
2750 tracehook_signal_handler(stepping);
2753 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2756 force_sigsegv(ksig->sig);
2758 signal_delivered(ksig, stepping);
2762 * It could be that complete_signal() picked us to notify about the
2763 * group-wide signal. Other threads should be notified now to take
2764 * the shared signals in @which since we will not.
2766 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2769 struct task_struct *t;
2771 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2772 if (sigisemptyset(&retarget))
2776 while_each_thread(tsk, t) {
2777 if (t->flags & PF_EXITING)
2780 if (!has_pending_signals(&retarget, &t->blocked))
2782 /* Remove the signals this thread can handle. */
2783 sigandsets(&retarget, &retarget, &t->blocked);
2785 if (!signal_pending(t))
2786 signal_wake_up(t, 0);
2788 if (sigisemptyset(&retarget))
2793 void exit_signals(struct task_struct *tsk)
2799 * @tsk is about to have PF_EXITING set - lock out users which
2800 * expect stable threadgroup.
2802 cgroup_threadgroup_change_begin(tsk);
2804 if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2805 tsk->flags |= PF_EXITING;
2806 cgroup_threadgroup_change_end(tsk);
2810 spin_lock_irq(&tsk->sighand->siglock);
2812 * From now this task is not visible for group-wide signals,
2813 * see wants_signal(), do_signal_stop().
2815 tsk->flags |= PF_EXITING;
2817 cgroup_threadgroup_change_end(tsk);
2819 if (!signal_pending(tsk))
2822 unblocked = tsk->blocked;
2823 signotset(&unblocked);
2824 retarget_shared_pending(tsk, &unblocked);
2826 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
2827 task_participate_group_stop(tsk))
2828 group_stop = CLD_STOPPED;
2830 spin_unlock_irq(&tsk->sighand->siglock);
2833 * If group stop has completed, deliver the notification. This
2834 * should always go to the real parent of the group leader.
2836 if (unlikely(group_stop)) {
2837 read_lock(&tasklist_lock);
2838 do_notify_parent_cldstop(tsk, false, group_stop);
2839 read_unlock(&tasklist_lock);
2844 * System call entry points.
2848 * sys_restart_syscall - restart a system call
2850 SYSCALL_DEFINE0(restart_syscall)
2852 struct restart_block *restart = ¤t->restart_block;
2853 return restart->fn(restart);
2856 long do_no_restart_syscall(struct restart_block *param)
2861 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
2863 if (signal_pending(tsk) && !thread_group_empty(tsk)) {
2864 sigset_t newblocked;
2865 /* A set of now blocked but previously unblocked signals. */
2866 sigandnsets(&newblocked, newset, ¤t->blocked);
2867 retarget_shared_pending(tsk, &newblocked);
2869 tsk->blocked = *newset;
2870 recalc_sigpending();
2874 * set_current_blocked - change current->blocked mask
2877 * It is wrong to change ->blocked directly, this helper should be used
2878 * to ensure the process can't miss a shared signal we are going to block.
2880 void set_current_blocked(sigset_t *newset)
2882 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
2883 __set_current_blocked(newset);
2886 void __set_current_blocked(const sigset_t *newset)
2888 struct task_struct *tsk = current;
2891 * In case the signal mask hasn't changed, there is nothing we need
2892 * to do. The current->blocked shouldn't be modified by other task.
2894 if (sigequalsets(&tsk->blocked, newset))
2897 spin_lock_irq(&tsk->sighand->siglock);
2898 __set_task_blocked(tsk, newset);
2899 spin_unlock_irq(&tsk->sighand->siglock);
2903 * This is also useful for kernel threads that want to temporarily
2904 * (or permanently) block certain signals.
2906 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2907 * interface happily blocks "unblockable" signals like SIGKILL
2910 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
2912 struct task_struct *tsk = current;
2915 /* Lockless, only current can change ->blocked, never from irq */
2917 *oldset = tsk->blocked;
2921 sigorsets(&newset, &tsk->blocked, set);
2924 sigandnsets(&newset, &tsk->blocked, set);
2933 __set_current_blocked(&newset);
2936 EXPORT_SYMBOL(sigprocmask);
2939 * The api helps set app-provided sigmasks.
2941 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2942 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
2944 int set_user_sigmask(const sigset_t __user *usigmask, sigset_t *set,
2945 sigset_t *oldset, size_t sigsetsize)
2950 if (sigsetsize != sizeof(sigset_t))
2952 if (copy_from_user(set, usigmask, sizeof(sigset_t)))
2955 *oldset = current->blocked;
2956 set_current_blocked(set);
2960 EXPORT_SYMBOL(set_user_sigmask);
2962 #ifdef CONFIG_COMPAT
2963 int set_compat_user_sigmask(const compat_sigset_t __user *usigmask,
2964 sigset_t *set, sigset_t *oldset,
2970 if (sigsetsize != sizeof(compat_sigset_t))
2972 if (get_compat_sigset(set, usigmask))
2975 *oldset = current->blocked;
2976 set_current_blocked(set);
2980 EXPORT_SYMBOL(set_compat_user_sigmask);
2984 * restore_user_sigmask:
2985 * usigmask: sigmask passed in from userland.
2986 * sigsaved: saved sigmask when the syscall started and changed the sigmask to
2989 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2990 * epoll_pwait where a new sigmask is passed in from userland for the syscalls.
2992 void restore_user_sigmask(const void __user *usigmask, sigset_t *sigsaved,
2999 * When signals are pending, do not restore them here.
3000 * Restoring sigmask here can lead to delivering signals that the above
3001 * syscalls are intended to block because of the sigmask passed in.
3004 current->saved_sigmask = *sigsaved;
3005 set_restore_sigmask();
3010 * This is needed because the fast syscall return path does not restore
3011 * saved_sigmask when signals are not pending.
3013 set_current_blocked(sigsaved);
3015 EXPORT_SYMBOL(restore_user_sigmask);
3018 * sys_rt_sigprocmask - change the list of currently blocked signals
3019 * @how: whether to add, remove, or set signals
3020 * @nset: stores pending signals
3021 * @oset: previous value of signal mask if non-null
3022 * @sigsetsize: size of sigset_t type
3024 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3025 sigset_t __user *, oset, size_t, sigsetsize)
3027 sigset_t old_set, new_set;
3030 /* XXX: Don't preclude handling different sized sigset_t's. */
3031 if (sigsetsize != sizeof(sigset_t))
3034 old_set = current->blocked;
3037 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3039 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3041 error = sigprocmask(how, &new_set, NULL);
3047 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3054 #ifdef CONFIG_COMPAT
3055 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3056 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3058 sigset_t old_set = current->blocked;
3060 /* XXX: Don't preclude handling different sized sigset_t's. */
3061 if (sigsetsize != sizeof(sigset_t))
3067 if (get_compat_sigset(&new_set, nset))
3069 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3071 error = sigprocmask(how, &new_set, NULL);
3075 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3079 static void do_sigpending(sigset_t *set)
3081 spin_lock_irq(¤t->sighand->siglock);
3082 sigorsets(set, ¤t->pending.signal,
3083 ¤t->signal->shared_pending.signal);
3084 spin_unlock_irq(¤t->sighand->siglock);
3086 /* Outside the lock because only this thread touches it. */
3087 sigandsets(set, ¤t->blocked, set);
3091 * sys_rt_sigpending - examine a pending signal that has been raised
3093 * @uset: stores pending signals
3094 * @sigsetsize: size of sigset_t type or larger
3096 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3100 if (sigsetsize > sizeof(*uset))
3103 do_sigpending(&set);
3105 if (copy_to_user(uset, &set, sigsetsize))
3111 #ifdef CONFIG_COMPAT
3112 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3113 compat_size_t, sigsetsize)
3117 if (sigsetsize > sizeof(*uset))
3120 do_sigpending(&set);
3122 return put_compat_sigset(uset, &set, sigsetsize);
3126 static const struct {
3127 unsigned char limit, layout;
3129 [SIGILL] = { NSIGILL, SIL_FAULT },
3130 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3131 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3132 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3133 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3135 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3137 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3138 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3139 [SIGSYS] = { NSIGSYS, SIL_SYS },
3142 static bool known_siginfo_layout(unsigned sig, int si_code)
3144 if (si_code == SI_KERNEL)
3146 else if ((si_code > SI_USER)) {
3147 if (sig_specific_sicodes(sig)) {
3148 if (si_code <= sig_sicodes[sig].limit)
3151 else if (si_code <= NSIGPOLL)
3154 else if (si_code >= SI_DETHREAD)
3156 else if (si_code == SI_ASYNCNL)
3161 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3163 enum siginfo_layout layout = SIL_KILL;
3164 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3165 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3166 (si_code <= sig_sicodes[sig].limit)) {
3167 layout = sig_sicodes[sig].layout;
3168 /* Handle the exceptions */
3169 if ((sig == SIGBUS) &&
3170 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3171 layout = SIL_FAULT_MCEERR;
3172 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3173 layout = SIL_FAULT_BNDERR;
3175 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3176 layout = SIL_FAULT_PKUERR;
3179 else if (si_code <= NSIGPOLL)
3182 if (si_code == SI_TIMER)
3184 else if (si_code == SI_SIGIO)
3186 else if (si_code < 0)
3192 static inline char __user *si_expansion(const siginfo_t __user *info)
3194 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3197 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3199 char __user *expansion = si_expansion(to);
3200 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3202 if (clear_user(expansion, SI_EXPANSION_SIZE))
3207 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3208 const siginfo_t __user *from)
3210 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3211 char __user *expansion = si_expansion(from);
3212 char buf[SI_EXPANSION_SIZE];
3215 * An unknown si_code might need more than
3216 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3217 * extra bytes are 0. This guarantees copy_siginfo_to_user
3218 * will return this data to userspace exactly.
3220 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3222 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3230 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3231 const siginfo_t __user *from)
3233 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3235 to->si_signo = signo;
3236 return post_copy_siginfo_from_user(to, from);
3239 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3241 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3243 return post_copy_siginfo_from_user(to, from);
3246 #ifdef CONFIG_COMPAT
3247 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
3248 const struct kernel_siginfo *from)
3249 #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
3251 return __copy_siginfo_to_user32(to, from, in_x32_syscall());
3253 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3254 const struct kernel_siginfo *from, bool x32_ABI)
3257 struct compat_siginfo new;
3258 memset(&new, 0, sizeof(new));
3260 new.si_signo = from->si_signo;
3261 new.si_errno = from->si_errno;
3262 new.si_code = from->si_code;
3263 switch(siginfo_layout(from->si_signo, from->si_code)) {
3265 new.si_pid = from->si_pid;
3266 new.si_uid = from->si_uid;
3269 new.si_tid = from->si_tid;
3270 new.si_overrun = from->si_overrun;
3271 new.si_int = from->si_int;
3274 new.si_band = from->si_band;
3275 new.si_fd = from->si_fd;
3278 new.si_addr = ptr_to_compat(from->si_addr);
3279 #ifdef __ARCH_SI_TRAPNO
3280 new.si_trapno = from->si_trapno;
3283 case SIL_FAULT_MCEERR:
3284 new.si_addr = ptr_to_compat(from->si_addr);
3285 #ifdef __ARCH_SI_TRAPNO
3286 new.si_trapno = from->si_trapno;
3288 new.si_addr_lsb = from->si_addr_lsb;
3290 case SIL_FAULT_BNDERR:
3291 new.si_addr = ptr_to_compat(from->si_addr);
3292 #ifdef __ARCH_SI_TRAPNO
3293 new.si_trapno = from->si_trapno;
3295 new.si_lower = ptr_to_compat(from->si_lower);
3296 new.si_upper = ptr_to_compat(from->si_upper);
3298 case SIL_FAULT_PKUERR:
3299 new.si_addr = ptr_to_compat(from->si_addr);
3300 #ifdef __ARCH_SI_TRAPNO
3301 new.si_trapno = from->si_trapno;
3303 new.si_pkey = from->si_pkey;
3306 new.si_pid = from->si_pid;
3307 new.si_uid = from->si_uid;
3308 new.si_status = from->si_status;
3309 #ifdef CONFIG_X86_X32_ABI
3311 new._sifields._sigchld_x32._utime = from->si_utime;
3312 new._sifields._sigchld_x32._stime = from->si_stime;
3316 new.si_utime = from->si_utime;
3317 new.si_stime = from->si_stime;
3321 new.si_pid = from->si_pid;
3322 new.si_uid = from->si_uid;
3323 new.si_int = from->si_int;
3326 new.si_call_addr = ptr_to_compat(from->si_call_addr);
3327 new.si_syscall = from->si_syscall;
3328 new.si_arch = from->si_arch;
3332 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3338 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3339 const struct compat_siginfo *from)
3342 to->si_signo = from->si_signo;
3343 to->si_errno = from->si_errno;
3344 to->si_code = from->si_code;
3345 switch(siginfo_layout(from->si_signo, from->si_code)) {
3347 to->si_pid = from->si_pid;
3348 to->si_uid = from->si_uid;
3351 to->si_tid = from->si_tid;
3352 to->si_overrun = from->si_overrun;
3353 to->si_int = from->si_int;
3356 to->si_band = from->si_band;
3357 to->si_fd = from->si_fd;
3360 to->si_addr = compat_ptr(from->si_addr);
3361 #ifdef __ARCH_SI_TRAPNO
3362 to->si_trapno = from->si_trapno;
3365 case SIL_FAULT_MCEERR:
3366 to->si_addr = compat_ptr(from->si_addr);
3367 #ifdef __ARCH_SI_TRAPNO
3368 to->si_trapno = from->si_trapno;
3370 to->si_addr_lsb = from->si_addr_lsb;
3372 case SIL_FAULT_BNDERR:
3373 to->si_addr = compat_ptr(from->si_addr);
3374 #ifdef __ARCH_SI_TRAPNO
3375 to->si_trapno = from->si_trapno;
3377 to->si_lower = compat_ptr(from->si_lower);
3378 to->si_upper = compat_ptr(from->si_upper);
3380 case SIL_FAULT_PKUERR:
3381 to->si_addr = compat_ptr(from->si_addr);
3382 #ifdef __ARCH_SI_TRAPNO
3383 to->si_trapno = from->si_trapno;
3385 to->si_pkey = from->si_pkey;
3388 to->si_pid = from->si_pid;
3389 to->si_uid = from->si_uid;
3390 to->si_status = from->si_status;
3391 #ifdef CONFIG_X86_X32_ABI
3392 if (in_x32_syscall()) {
3393 to->si_utime = from->_sifields._sigchld_x32._utime;
3394 to->si_stime = from->_sifields._sigchld_x32._stime;
3398 to->si_utime = from->si_utime;
3399 to->si_stime = from->si_stime;
3403 to->si_pid = from->si_pid;
3404 to->si_uid = from->si_uid;
3405 to->si_int = from->si_int;
3408 to->si_call_addr = compat_ptr(from->si_call_addr);
3409 to->si_syscall = from->si_syscall;
3410 to->si_arch = from->si_arch;
3416 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3417 const struct compat_siginfo __user *ufrom)
3419 struct compat_siginfo from;
3421 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3424 from.si_signo = signo;
3425 return post_copy_siginfo_from_user32(to, &from);
3428 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3429 const struct compat_siginfo __user *ufrom)
3431 struct compat_siginfo from;
3433 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3436 return post_copy_siginfo_from_user32(to, &from);
3438 #endif /* CONFIG_COMPAT */
3441 * do_sigtimedwait - wait for queued signals specified in @which
3442 * @which: queued signals to wait for
3443 * @info: if non-null, the signal's siginfo is returned here
3444 * @ts: upper bound on process time suspension
3446 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3447 const struct timespec64 *ts)
3449 ktime_t *to = NULL, timeout = KTIME_MAX;
3450 struct task_struct *tsk = current;
3451 sigset_t mask = *which;
3455 if (!timespec64_valid(ts))
3457 timeout = timespec64_to_ktime(*ts);
3462 * Invert the set of allowed signals to get those we want to block.
3464 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3467 spin_lock_irq(&tsk->sighand->siglock);
3468 sig = dequeue_signal(tsk, &mask, info);
3469 if (!sig && timeout) {
3471 * None ready, temporarily unblock those we're interested
3472 * while we are sleeping in so that we'll be awakened when
3473 * they arrive. Unblocking is always fine, we can avoid
3474 * set_current_blocked().
3476 tsk->real_blocked = tsk->blocked;
3477 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3478 recalc_sigpending();
3479 spin_unlock_irq(&tsk->sighand->siglock);
3481 __set_current_state(TASK_INTERRUPTIBLE);
3482 ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3484 spin_lock_irq(&tsk->sighand->siglock);
3485 __set_task_blocked(tsk, &tsk->real_blocked);
3486 sigemptyset(&tsk->real_blocked);
3487 sig = dequeue_signal(tsk, &mask, info);
3489 spin_unlock_irq(&tsk->sighand->siglock);
3493 return ret ? -EINTR : -EAGAIN;
3497 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3499 * @uthese: queued signals to wait for
3500 * @uinfo: if non-null, the signal's siginfo is returned here
3501 * @uts: upper bound on process time suspension
3502 * @sigsetsize: size of sigset_t type
3504 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3505 siginfo_t __user *, uinfo,
3506 const struct __kernel_timespec __user *, uts,
3510 struct timespec64 ts;
3511 kernel_siginfo_t info;
3514 /* XXX: Don't preclude handling different sized sigset_t's. */
3515 if (sigsetsize != sizeof(sigset_t))
3518 if (copy_from_user(&these, uthese, sizeof(these)))
3522 if (get_timespec64(&ts, uts))
3526 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3528 if (ret > 0 && uinfo) {
3529 if (copy_siginfo_to_user(uinfo, &info))
3536 #ifdef CONFIG_COMPAT_32BIT_TIME
3537 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3538 siginfo_t __user *, uinfo,
3539 const struct old_timespec32 __user *, uts,
3543 struct timespec64 ts;
3544 kernel_siginfo_t info;
3547 if (sigsetsize != sizeof(sigset_t))
3550 if (copy_from_user(&these, uthese, sizeof(these)))
3554 if (get_old_timespec32(&ts, uts))
3558 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3560 if (ret > 0 && uinfo) {
3561 if (copy_siginfo_to_user(uinfo, &info))
3569 #ifdef CONFIG_COMPAT
3570 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3571 struct compat_siginfo __user *, uinfo,
3572 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3575 struct timespec64 t;
3576 kernel_siginfo_t info;
3579 if (sigsetsize != sizeof(sigset_t))
3582 if (get_compat_sigset(&s, uthese))
3586 if (get_timespec64(&t, uts))
3590 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3592 if (ret > 0 && uinfo) {
3593 if (copy_siginfo_to_user32(uinfo, &info))
3600 #ifdef CONFIG_COMPAT_32BIT_TIME
3601 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3602 struct compat_siginfo __user *, uinfo,
3603 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3606 struct timespec64 t;
3607 kernel_siginfo_t info;
3610 if (sigsetsize != sizeof(sigset_t))
3613 if (get_compat_sigset(&s, uthese))
3617 if (get_old_timespec32(&t, uts))
3621 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3623 if (ret > 0 && uinfo) {
3624 if (copy_siginfo_to_user32(uinfo, &info))
3633 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3635 clear_siginfo(info);
3636 info->si_signo = sig;
3638 info->si_code = SI_USER;
3639 info->si_pid = task_tgid_vnr(current);
3640 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3644 * sys_kill - send a signal to a process
3645 * @pid: the PID of the process
3646 * @sig: signal to be sent
3648 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3650 struct kernel_siginfo info;
3652 prepare_kill_siginfo(sig, &info);
3654 return kill_something_info(sig, &info, pid);
3658 * Verify that the signaler and signalee either are in the same pid namespace
3659 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3662 static bool access_pidfd_pidns(struct pid *pid)
3664 struct pid_namespace *active = task_active_pid_ns(current);
3665 struct pid_namespace *p = ns_of_pid(pid);
3678 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, siginfo_t *info)
3680 #ifdef CONFIG_COMPAT
3682 * Avoid hooking up compat syscalls and instead handle necessary
3683 * conversions here. Note, this is a stop-gap measure and should not be
3684 * considered a generic solution.
3686 if (in_compat_syscall())
3687 return copy_siginfo_from_user32(
3688 kinfo, (struct compat_siginfo __user *)info);
3690 return copy_siginfo_from_user(kinfo, info);
3693 static struct pid *pidfd_to_pid(const struct file *file)
3695 if (file->f_op == &pidfd_fops)
3696 return file->private_data;
3698 return tgid_pidfd_to_pid(file);
3702 * sys_pidfd_send_signal - Signal a process through a pidfd
3703 * @pidfd: file descriptor of the process
3704 * @sig: signal to send
3705 * @info: signal info
3706 * @flags: future flags
3708 * The syscall currently only signals via PIDTYPE_PID which covers
3709 * kill(<positive-pid>, <signal>. It does not signal threads or process
3711 * In order to extend the syscall to threads and process groups the @flags
3712 * argument should be used. In essence, the @flags argument will determine
3713 * what is signaled and not the file descriptor itself. Put in other words,
3714 * grouping is a property of the flags argument not a property of the file
3717 * Return: 0 on success, negative errno on failure
3719 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3720 siginfo_t __user *, info, unsigned int, flags)
3725 kernel_siginfo_t kinfo;
3727 /* Enforce flags be set to 0 until we add an extension. */
3735 /* Is this a pidfd? */
3736 pid = pidfd_to_pid(f.file);
3743 if (!access_pidfd_pidns(pid))
3747 ret = copy_siginfo_from_user_any(&kinfo, info);
3752 if (unlikely(sig != kinfo.si_signo))
3755 /* Only allow sending arbitrary signals to yourself. */
3757 if ((task_pid(current) != pid) &&
3758 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3761 prepare_kill_siginfo(sig, &kinfo);
3764 ret = kill_pid_info(sig, &kinfo, pid);
3772 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3774 struct task_struct *p;
3778 p = find_task_by_vpid(pid);
3779 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3780 error = check_kill_permission(sig, info, p);
3782 * The null signal is a permissions and process existence
3783 * probe. No signal is actually delivered.
3785 if (!error && sig) {
3786 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3788 * If lock_task_sighand() failed we pretend the task
3789 * dies after receiving the signal. The window is tiny,
3790 * and the signal is private anyway.
3792 if (unlikely(error == -ESRCH))
3801 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3803 struct kernel_siginfo info;
3805 clear_siginfo(&info);
3806 info.si_signo = sig;
3808 info.si_code = SI_TKILL;
3809 info.si_pid = task_tgid_vnr(current);
3810 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3812 return do_send_specific(tgid, pid, sig, &info);
3816 * sys_tgkill - send signal to one specific thread
3817 * @tgid: the thread group ID of the thread
3818 * @pid: the PID of the thread
3819 * @sig: signal to be sent
3821 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3822 * exists but it's not belonging to the target process anymore. This
3823 * method solves the problem of threads exiting and PIDs getting reused.
3825 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
3827 /* This is only valid for single tasks */
3828 if (pid <= 0 || tgid <= 0)
3831 return do_tkill(tgid, pid, sig);
3835 * sys_tkill - send signal to one specific task
3836 * @pid: the PID of the task
3837 * @sig: signal to be sent
3839 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3841 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
3843 /* This is only valid for single tasks */
3847 return do_tkill(0, pid, sig);
3850 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
3852 /* Not even root can pretend to send signals from the kernel.
3853 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3855 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3856 (task_pid_vnr(current) != pid))
3859 /* POSIX.1b doesn't mention process groups. */
3860 return kill_proc_info(sig, info, pid);
3864 * sys_rt_sigqueueinfo - send signal information to a signal
3865 * @pid: the PID of the thread
3866 * @sig: signal to be sent
3867 * @uinfo: signal info to be sent
3869 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
3870 siginfo_t __user *, uinfo)
3872 kernel_siginfo_t info;
3873 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3876 return do_rt_sigqueueinfo(pid, sig, &info);
3879 #ifdef CONFIG_COMPAT
3880 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
3883 struct compat_siginfo __user *, uinfo)
3885 kernel_siginfo_t info;
3886 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3889 return do_rt_sigqueueinfo(pid, sig, &info);
3893 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
3895 /* This is only valid for single tasks */
3896 if (pid <= 0 || tgid <= 0)
3899 /* Not even root can pretend to send signals from the kernel.
3900 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3902 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
3903 (task_pid_vnr(current) != pid))
3906 return do_send_specific(tgid, pid, sig, info);
3909 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
3910 siginfo_t __user *, uinfo)
3912 kernel_siginfo_t info;
3913 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
3916 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3919 #ifdef CONFIG_COMPAT
3920 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
3924 struct compat_siginfo __user *, uinfo)
3926 kernel_siginfo_t info;
3927 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
3930 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
3935 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3937 void kernel_sigaction(int sig, __sighandler_t action)
3939 spin_lock_irq(¤t->sighand->siglock);
3940 current->sighand->action[sig - 1].sa.sa_handler = action;
3941 if (action == SIG_IGN) {
3945 sigaddset(&mask, sig);
3947 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
3948 flush_sigqueue_mask(&mask, ¤t->pending);
3949 recalc_sigpending();
3951 spin_unlock_irq(¤t->sighand->siglock);
3953 EXPORT_SYMBOL(kernel_sigaction);
3955 void __weak sigaction_compat_abi(struct k_sigaction *act,
3956 struct k_sigaction *oact)
3960 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
3962 struct task_struct *p = current, *t;
3963 struct k_sigaction *k;
3966 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
3969 k = &p->sighand->action[sig-1];
3971 spin_lock_irq(&p->sighand->siglock);
3975 sigaction_compat_abi(act, oact);
3978 sigdelsetmask(&act->sa.sa_mask,
3979 sigmask(SIGKILL) | sigmask(SIGSTOP));
3983 * "Setting a signal action to SIG_IGN for a signal that is
3984 * pending shall cause the pending signal to be discarded,
3985 * whether or not it is blocked."
3987 * "Setting a signal action to SIG_DFL for a signal that is
3988 * pending and whose default action is to ignore the signal
3989 * (for example, SIGCHLD), shall cause the pending signal to
3990 * be discarded, whether or not it is blocked"
3992 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
3994 sigaddset(&mask, sig);
3995 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
3996 for_each_thread(p, t)
3997 flush_sigqueue_mask(&mask, &t->pending);
4001 spin_unlock_irq(&p->sighand->siglock);
4006 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4009 struct task_struct *t = current;
4012 memset(oss, 0, sizeof(stack_t));
4013 oss->ss_sp = (void __user *) t->sas_ss_sp;
4014 oss->ss_size = t->sas_ss_size;
4015 oss->ss_flags = sas_ss_flags(sp) |
4016 (current->sas_ss_flags & SS_FLAG_BITS);
4020 void __user *ss_sp = ss->ss_sp;
4021 size_t ss_size = ss->ss_size;
4022 unsigned ss_flags = ss->ss_flags;
4025 if (unlikely(on_sig_stack(sp)))
4028 ss_mode = ss_flags & ~SS_FLAG_BITS;
4029 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4033 if (ss_mode == SS_DISABLE) {
4037 if (unlikely(ss_size < min_ss_size))
4041 t->sas_ss_sp = (unsigned long) ss_sp;
4042 t->sas_ss_size = ss_size;
4043 t->sas_ss_flags = ss_flags;
4048 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4052 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4054 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4055 current_user_stack_pointer(),
4057 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4062 int restore_altstack(const stack_t __user *uss)
4065 if (copy_from_user(&new, uss, sizeof(stack_t)))
4067 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4069 /* squash all but EFAULT for now */
4073 int __save_altstack(stack_t __user *uss, unsigned long sp)
4075 struct task_struct *t = current;
4076 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4077 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4078 __put_user(t->sas_ss_size, &uss->ss_size);
4081 if (t->sas_ss_flags & SS_AUTODISARM)
4086 #ifdef CONFIG_COMPAT
4087 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4088 compat_stack_t __user *uoss_ptr)
4094 compat_stack_t uss32;
4095 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4097 uss.ss_sp = compat_ptr(uss32.ss_sp);
4098 uss.ss_flags = uss32.ss_flags;
4099 uss.ss_size = uss32.ss_size;
4101 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4102 compat_user_stack_pointer(),
4103 COMPAT_MINSIGSTKSZ);
4104 if (ret >= 0 && uoss_ptr) {
4106 memset(&old, 0, sizeof(old));
4107 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4108 old.ss_flags = uoss.ss_flags;
4109 old.ss_size = uoss.ss_size;
4110 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4116 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4117 const compat_stack_t __user *, uss_ptr,
4118 compat_stack_t __user *, uoss_ptr)
4120 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4123 int compat_restore_altstack(const compat_stack_t __user *uss)
4125 int err = do_compat_sigaltstack(uss, NULL);
4126 /* squash all but -EFAULT for now */
4127 return err == -EFAULT ? err : 0;
4130 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4133 struct task_struct *t = current;
4134 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4136 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4137 __put_user(t->sas_ss_size, &uss->ss_size);
4140 if (t->sas_ss_flags & SS_AUTODISARM)
4146 #ifdef __ARCH_WANT_SYS_SIGPENDING
4149 * sys_sigpending - examine pending signals
4150 * @uset: where mask of pending signal is returned
4152 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4156 if (sizeof(old_sigset_t) > sizeof(*uset))
4159 do_sigpending(&set);
4161 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4167 #ifdef CONFIG_COMPAT
4168 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4172 do_sigpending(&set);
4174 return put_user(set.sig[0], set32);
4180 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4182 * sys_sigprocmask - examine and change blocked signals
4183 * @how: whether to add, remove, or set signals
4184 * @nset: signals to add or remove (if non-null)
4185 * @oset: previous value of signal mask if non-null
4187 * Some platforms have their own version with special arguments;
4188 * others support only sys_rt_sigprocmask.
4191 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4192 old_sigset_t __user *, oset)
4194 old_sigset_t old_set, new_set;
4195 sigset_t new_blocked;
4197 old_set = current->blocked.sig[0];
4200 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4203 new_blocked = current->blocked;
4207 sigaddsetmask(&new_blocked, new_set);
4210 sigdelsetmask(&new_blocked, new_set);
4213 new_blocked.sig[0] = new_set;
4219 set_current_blocked(&new_blocked);
4223 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4229 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4231 #ifndef CONFIG_ODD_RT_SIGACTION
4233 * sys_rt_sigaction - alter an action taken by a process
4234 * @sig: signal to be sent
4235 * @act: new sigaction
4236 * @oact: used to save the previous sigaction
4237 * @sigsetsize: size of sigset_t type
4239 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4240 const struct sigaction __user *, act,
4241 struct sigaction __user *, oact,
4244 struct k_sigaction new_sa, old_sa;
4247 /* XXX: Don't preclude handling different sized sigset_t's. */
4248 if (sigsetsize != sizeof(sigset_t))
4251 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4254 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4258 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4263 #ifdef CONFIG_COMPAT
4264 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4265 const struct compat_sigaction __user *, act,
4266 struct compat_sigaction __user *, oact,
4267 compat_size_t, sigsetsize)
4269 struct k_sigaction new_ka, old_ka;
4270 #ifdef __ARCH_HAS_SA_RESTORER
4271 compat_uptr_t restorer;
4275 /* XXX: Don't preclude handling different sized sigset_t's. */
4276 if (sigsetsize != sizeof(compat_sigset_t))
4280 compat_uptr_t handler;
4281 ret = get_user(handler, &act->sa_handler);
4282 new_ka.sa.sa_handler = compat_ptr(handler);
4283 #ifdef __ARCH_HAS_SA_RESTORER
4284 ret |= get_user(restorer, &act->sa_restorer);
4285 new_ka.sa.sa_restorer = compat_ptr(restorer);
4287 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4288 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4293 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4295 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4297 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4298 sizeof(oact->sa_mask));
4299 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4300 #ifdef __ARCH_HAS_SA_RESTORER
4301 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4302 &oact->sa_restorer);
4308 #endif /* !CONFIG_ODD_RT_SIGACTION */
4310 #ifdef CONFIG_OLD_SIGACTION
4311 SYSCALL_DEFINE3(sigaction, int, sig,
4312 const struct old_sigaction __user *, act,
4313 struct old_sigaction __user *, oact)
4315 struct k_sigaction new_ka, old_ka;
4320 if (!access_ok(act, sizeof(*act)) ||
4321 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4322 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4323 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4324 __get_user(mask, &act->sa_mask))
4326 #ifdef __ARCH_HAS_KA_RESTORER
4327 new_ka.ka_restorer = NULL;
4329 siginitset(&new_ka.sa.sa_mask, mask);
4332 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4335 if (!access_ok(oact, sizeof(*oact)) ||
4336 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4337 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4338 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4339 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4346 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4347 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4348 const struct compat_old_sigaction __user *, act,
4349 struct compat_old_sigaction __user *, oact)
4351 struct k_sigaction new_ka, old_ka;
4353 compat_old_sigset_t mask;
4354 compat_uptr_t handler, restorer;
4357 if (!access_ok(act, sizeof(*act)) ||
4358 __get_user(handler, &act->sa_handler) ||
4359 __get_user(restorer, &act->sa_restorer) ||
4360 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4361 __get_user(mask, &act->sa_mask))
4364 #ifdef __ARCH_HAS_KA_RESTORER
4365 new_ka.ka_restorer = NULL;
4367 new_ka.sa.sa_handler = compat_ptr(handler);
4368 new_ka.sa.sa_restorer = compat_ptr(restorer);
4369 siginitset(&new_ka.sa.sa_mask, mask);
4372 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4375 if (!access_ok(oact, sizeof(*oact)) ||
4376 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4377 &oact->sa_handler) ||
4378 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4379 &oact->sa_restorer) ||
4380 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4381 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4388 #ifdef CONFIG_SGETMASK_SYSCALL
4391 * For backwards compatibility. Functionality superseded by sigprocmask.
4393 SYSCALL_DEFINE0(sgetmask)
4396 return current->blocked.sig[0];
4399 SYSCALL_DEFINE1(ssetmask, int, newmask)
4401 int old = current->blocked.sig[0];
4404 siginitset(&newset, newmask);
4405 set_current_blocked(&newset);
4409 #endif /* CONFIG_SGETMASK_SYSCALL */
4411 #ifdef __ARCH_WANT_SYS_SIGNAL
4413 * For backwards compatibility. Functionality superseded by sigaction.
4415 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4417 struct k_sigaction new_sa, old_sa;
4420 new_sa.sa.sa_handler = handler;
4421 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4422 sigemptyset(&new_sa.sa.sa_mask);
4424 ret = do_sigaction(sig, &new_sa, &old_sa);
4426 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4428 #endif /* __ARCH_WANT_SYS_SIGNAL */
4430 #ifdef __ARCH_WANT_SYS_PAUSE
4432 SYSCALL_DEFINE0(pause)
4434 while (!signal_pending(current)) {
4435 __set_current_state(TASK_INTERRUPTIBLE);
4438 return -ERESTARTNOHAND;
4443 static int sigsuspend(sigset_t *set)
4445 current->saved_sigmask = current->blocked;
4446 set_current_blocked(set);
4448 while (!signal_pending(current)) {
4449 __set_current_state(TASK_INTERRUPTIBLE);
4452 set_restore_sigmask();
4453 return -ERESTARTNOHAND;
4457 * sys_rt_sigsuspend - replace the signal mask for a value with the
4458 * @unewset value until a signal is received
4459 * @unewset: new signal mask value
4460 * @sigsetsize: size of sigset_t type
4462 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4466 /* XXX: Don't preclude handling different sized sigset_t's. */
4467 if (sigsetsize != sizeof(sigset_t))
4470 if (copy_from_user(&newset, unewset, sizeof(newset)))
4472 return sigsuspend(&newset);
4475 #ifdef CONFIG_COMPAT
4476 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4480 /* XXX: Don't preclude handling different sized sigset_t's. */
4481 if (sigsetsize != sizeof(sigset_t))
4484 if (get_compat_sigset(&newset, unewset))
4486 return sigsuspend(&newset);
4490 #ifdef CONFIG_OLD_SIGSUSPEND
4491 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4494 siginitset(&blocked, mask);
4495 return sigsuspend(&blocked);
4498 #ifdef CONFIG_OLD_SIGSUSPEND3
4499 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4502 siginitset(&blocked, mask);
4503 return sigsuspend(&blocked);
4507 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4512 static inline void siginfo_buildtime_checks(void)
4514 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4516 /* Verify the offsets in the two siginfos match */
4517 #define CHECK_OFFSET(field) \
4518 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4521 CHECK_OFFSET(si_pid);
4522 CHECK_OFFSET(si_uid);
4525 CHECK_OFFSET(si_tid);
4526 CHECK_OFFSET(si_overrun);
4527 CHECK_OFFSET(si_value);
4530 CHECK_OFFSET(si_pid);
4531 CHECK_OFFSET(si_uid);
4532 CHECK_OFFSET(si_value);
4535 CHECK_OFFSET(si_pid);
4536 CHECK_OFFSET(si_uid);
4537 CHECK_OFFSET(si_status);
4538 CHECK_OFFSET(si_utime);
4539 CHECK_OFFSET(si_stime);
4542 CHECK_OFFSET(si_addr);
4543 CHECK_OFFSET(si_addr_lsb);
4544 CHECK_OFFSET(si_lower);
4545 CHECK_OFFSET(si_upper);
4546 CHECK_OFFSET(si_pkey);
4549 CHECK_OFFSET(si_band);
4550 CHECK_OFFSET(si_fd);
4553 CHECK_OFFSET(si_call_addr);
4554 CHECK_OFFSET(si_syscall);
4555 CHECK_OFFSET(si_arch);
4559 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4560 offsetof(struct siginfo, si_addr));
4561 if (sizeof(int) == sizeof(void __user *)) {
4562 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4563 sizeof(void __user *));
4565 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4566 sizeof_field(struct siginfo, si_uid)) !=
4567 sizeof(void __user *));
4568 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4569 offsetof(struct siginfo, si_uid));
4571 #ifdef CONFIG_COMPAT
4572 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4573 offsetof(struct compat_siginfo, si_addr));
4574 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4575 sizeof(compat_uptr_t));
4576 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4577 sizeof_field(struct siginfo, si_pid));
4581 void __init signals_init(void)
4583 siginfo_buildtime_checks();
4585 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
4588 #ifdef CONFIG_KGDB_KDB
4589 #include <linux/kdb.h>
4591 * kdb_send_sig - Allows kdb to send signals without exposing
4592 * signal internals. This function checks if the required locks are
4593 * available before calling the main signal code, to avoid kdb
4596 void kdb_send_sig(struct task_struct *t, int sig)
4598 static struct task_struct *kdb_prev_t;
4600 if (!spin_trylock(&t->sighand->siglock)) {
4601 kdb_printf("Can't do kill command now.\n"
4602 "The sigmask lock is held somewhere else in "
4603 "kernel, try again later\n");
4606 new_t = kdb_prev_t != t;
4608 if (t->state != TASK_RUNNING && new_t) {
4609 spin_unlock(&t->sighand->siglock);
4610 kdb_printf("Process is not RUNNING, sending a signal from "
4611 "kdb risks deadlock\n"
4612 "on the run queue locks. "
4613 "The signal has _not_ been sent.\n"
4614 "Reissue the kill command if you want to risk "
4618 ret = send_signal(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4619 spin_unlock(&t->sighand->siglock);
4621 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4624 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4626 #endif /* CONFIG_KGDB_KDB */