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>
26 #include <linux/proc_fs.h>
27 #include <linux/tty.h>
28 #include <linux/binfmts.h>
29 #include <linux/coredump.h>
30 #include <linux/security.h>
31 #include <linux/syscalls.h>
32 #include <linux/ptrace.h>
33 #include <linux/signal.h>
34 #include <linux/signalfd.h>
35 #include <linux/ratelimit.h>
36 #include <linux/task_work.h>
37 #include <linux/capability.h>
38 #include <linux/freezer.h>
39 #include <linux/pid_namespace.h>
40 #include <linux/nsproxy.h>
41 #include <linux/user_namespace.h>
42 #include <linux/uprobes.h>
43 #include <linux/compat.h>
44 #include <linux/cn_proc.h>
45 #include <linux/compiler.h>
46 #include <linux/posix-timers.h>
47 #include <linux/cgroup.h>
48 #include <linux/audit.h>
49 #include <linux/sysctl.h>
51 #define CREATE_TRACE_POINTS
52 #include <trace/events/signal.h>
54 #include <asm/param.h>
55 #include <linux/uaccess.h>
56 #include <asm/unistd.h>
57 #include <asm/siginfo.h>
58 #include <asm/cacheflush.h>
59 #include <asm/syscall.h> /* for syscall_get_* */
62 * SLAB caches for signal bits.
65 static struct kmem_cache *sigqueue_cachep;
67 int print_fatal_signals __read_mostly;
69 static void __user *sig_handler(struct task_struct *t, int sig)
71 return t->sighand->action[sig - 1].sa.sa_handler;
74 static inline bool sig_handler_ignored(void __user *handler, int sig)
76 /* Is it explicitly or implicitly ignored? */
77 return handler == SIG_IGN ||
78 (handler == SIG_DFL && sig_kernel_ignore(sig));
81 static bool sig_task_ignored(struct task_struct *t, int sig, bool force)
85 handler = sig_handler(t, sig);
87 /* SIGKILL and SIGSTOP may not be sent to the global init */
88 if (unlikely(is_global_init(t) && sig_kernel_only(sig)))
91 if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
92 handler == SIG_DFL && !(force && sig_kernel_only(sig)))
95 /* Only allow kernel generated signals to this kthread */
96 if (unlikely((t->flags & PF_KTHREAD) &&
97 (handler == SIG_KTHREAD_KERNEL) && !force))
100 return sig_handler_ignored(handler, sig);
103 static bool sig_ignored(struct task_struct *t, int sig, bool force)
106 * Blocked signals are never ignored, since the
107 * signal handler may change by the time it is
110 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
114 * Tracers may want to know about even ignored signal unless it
115 * is SIGKILL which can't be reported anyway but can be ignored
116 * by SIGNAL_UNKILLABLE task.
118 if (t->ptrace && sig != SIGKILL)
121 return sig_task_ignored(t, sig, force);
125 * Re-calculate pending state from the set of locally pending
126 * signals, globally pending signals, and blocked signals.
128 static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
133 switch (_NSIG_WORDS) {
135 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
136 ready |= signal->sig[i] &~ blocked->sig[i];
139 case 4: ready = signal->sig[3] &~ blocked->sig[3];
140 ready |= signal->sig[2] &~ blocked->sig[2];
141 ready |= signal->sig[1] &~ blocked->sig[1];
142 ready |= signal->sig[0] &~ blocked->sig[0];
145 case 2: ready = signal->sig[1] &~ blocked->sig[1];
146 ready |= signal->sig[0] &~ blocked->sig[0];
149 case 1: ready = signal->sig[0] &~ blocked->sig[0];
154 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
156 static bool recalc_sigpending_tsk(struct task_struct *t)
158 if ((t->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) ||
159 PENDING(&t->pending, &t->blocked) ||
160 PENDING(&t->signal->shared_pending, &t->blocked) ||
161 cgroup_task_frozen(t)) {
162 set_tsk_thread_flag(t, TIF_SIGPENDING);
167 * We must never clear the flag in another thread, or in current
168 * when it's possible the current syscall is returning -ERESTART*.
169 * So we don't clear it here, and only callers who know they should do.
175 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
176 * This is superfluous when called on current, the wakeup is a harmless no-op.
178 void recalc_sigpending_and_wake(struct task_struct *t)
180 if (recalc_sigpending_tsk(t))
181 signal_wake_up(t, 0);
184 void recalc_sigpending(void)
186 if (!recalc_sigpending_tsk(current) && !freezing(current))
187 clear_thread_flag(TIF_SIGPENDING);
190 EXPORT_SYMBOL(recalc_sigpending);
192 void calculate_sigpending(void)
194 /* Have any signals or users of TIF_SIGPENDING been delayed
197 spin_lock_irq(¤t->sighand->siglock);
198 set_tsk_thread_flag(current, TIF_SIGPENDING);
200 spin_unlock_irq(¤t->sighand->siglock);
203 /* Given the mask, find the first available signal that should be serviced. */
205 #define SYNCHRONOUS_MASK \
206 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
207 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
209 int next_signal(struct sigpending *pending, sigset_t *mask)
211 unsigned long i, *s, *m, x;
214 s = pending->signal.sig;
218 * Handle the first word specially: it contains the
219 * synchronous signals that need to be dequeued first.
223 if (x & SYNCHRONOUS_MASK)
224 x &= SYNCHRONOUS_MASK;
229 switch (_NSIG_WORDS) {
231 for (i = 1; i < _NSIG_WORDS; ++i) {
235 sig = ffz(~x) + i*_NSIG_BPW + 1;
244 sig = ffz(~x) + _NSIG_BPW + 1;
255 static inline void print_dropped_signal(int sig)
257 static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
259 if (!print_fatal_signals)
262 if (!__ratelimit(&ratelimit_state))
265 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
266 current->comm, current->pid, sig);
270 * task_set_jobctl_pending - set jobctl pending bits
272 * @mask: pending bits to set
274 * Clear @mask from @task->jobctl. @mask must be subset of
275 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
276 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
277 * cleared. If @task is already being killed or exiting, this function
281 * Must be called with @task->sighand->siglock held.
284 * %true if @mask is set, %false if made noop because @task was dying.
286 bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask)
288 BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
289 JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
290 BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
292 if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
295 if (mask & JOBCTL_STOP_SIGMASK)
296 task->jobctl &= ~JOBCTL_STOP_SIGMASK;
298 task->jobctl |= mask;
303 * task_clear_jobctl_trapping - clear jobctl trapping bit
306 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
307 * Clear it and wake up the ptracer. Note that we don't need any further
308 * locking. @task->siglock guarantees that @task->parent points to the
312 * Must be called with @task->sighand->siglock held.
314 void task_clear_jobctl_trapping(struct task_struct *task)
316 if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
317 task->jobctl &= ~JOBCTL_TRAPPING;
318 smp_mb(); /* advised by wake_up_bit() */
319 wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
324 * task_clear_jobctl_pending - clear jobctl pending bits
326 * @mask: pending bits to clear
328 * Clear @mask from @task->jobctl. @mask must be subset of
329 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
330 * STOP bits are cleared together.
332 * If clearing of @mask leaves no stop or trap pending, this function calls
333 * task_clear_jobctl_trapping().
336 * Must be called with @task->sighand->siglock held.
338 void task_clear_jobctl_pending(struct task_struct *task, unsigned long mask)
340 BUG_ON(mask & ~JOBCTL_PENDING_MASK);
342 if (mask & JOBCTL_STOP_PENDING)
343 mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
345 task->jobctl &= ~mask;
347 if (!(task->jobctl & JOBCTL_PENDING_MASK))
348 task_clear_jobctl_trapping(task);
352 * task_participate_group_stop - participate in a group stop
353 * @task: task participating in a group stop
355 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
356 * Group stop states are cleared and the group stop count is consumed if
357 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
358 * stop, the appropriate `SIGNAL_*` flags are set.
361 * Must be called with @task->sighand->siglock held.
364 * %true if group stop completion should be notified to the parent, %false
367 static bool task_participate_group_stop(struct task_struct *task)
369 struct signal_struct *sig = task->signal;
370 bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
372 WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
374 task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
379 if (!WARN_ON_ONCE(sig->group_stop_count == 0))
380 sig->group_stop_count--;
383 * Tell the caller to notify completion iff we are entering into a
384 * fresh group stop. Read comment in do_signal_stop() for details.
386 if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
387 signal_set_stop_flags(sig, SIGNAL_STOP_STOPPED);
393 void task_join_group_stop(struct task_struct *task)
395 unsigned long mask = current->jobctl & JOBCTL_STOP_SIGMASK;
396 struct signal_struct *sig = current->signal;
398 if (sig->group_stop_count) {
399 sig->group_stop_count++;
400 mask |= JOBCTL_STOP_CONSUME;
401 } else if (!(sig->flags & SIGNAL_STOP_STOPPED))
404 /* Have the new thread join an on-going signal group stop */
405 task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
409 * allocate a new signal queue record
410 * - this may be called without locks if and only if t == current, otherwise an
411 * appropriate lock must be held to stop the target task from exiting
413 static struct sigqueue *
414 __sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
415 int override_rlimit, const unsigned int sigqueue_flags)
417 struct sigqueue *q = NULL;
418 struct ucounts *ucounts = NULL;
422 * Protect access to @t credentials. This can go away when all
423 * callers hold rcu read lock.
425 * NOTE! A pending signal will hold on to the user refcount,
426 * and we get/put the refcount only when the sigpending count
427 * changes from/to zero.
430 ucounts = task_ucounts(t);
431 sigpending = inc_rlimit_get_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
436 if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
437 q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
439 print_dropped_signal(sig);
442 if (unlikely(q == NULL)) {
443 dec_rlimit_put_ucounts(ucounts, UCOUNT_RLIMIT_SIGPENDING);
445 INIT_LIST_HEAD(&q->list);
446 q->flags = sigqueue_flags;
447 q->ucounts = ucounts;
452 static void __sigqueue_free(struct sigqueue *q)
454 if (q->flags & SIGQUEUE_PREALLOC)
457 dec_rlimit_put_ucounts(q->ucounts, UCOUNT_RLIMIT_SIGPENDING);
460 kmem_cache_free(sigqueue_cachep, q);
463 void flush_sigqueue(struct sigpending *queue)
467 sigemptyset(&queue->signal);
468 while (!list_empty(&queue->list)) {
469 q = list_entry(queue->list.next, struct sigqueue , list);
470 list_del_init(&q->list);
476 * Flush all pending signals for this kthread.
478 void flush_signals(struct task_struct *t)
482 spin_lock_irqsave(&t->sighand->siglock, flags);
483 clear_tsk_thread_flag(t, TIF_SIGPENDING);
484 flush_sigqueue(&t->pending);
485 flush_sigqueue(&t->signal->shared_pending);
486 spin_unlock_irqrestore(&t->sighand->siglock, flags);
488 EXPORT_SYMBOL(flush_signals);
490 #ifdef CONFIG_POSIX_TIMERS
491 static void __flush_itimer_signals(struct sigpending *pending)
493 sigset_t signal, retain;
494 struct sigqueue *q, *n;
496 signal = pending->signal;
497 sigemptyset(&retain);
499 list_for_each_entry_safe(q, n, &pending->list, list) {
500 int sig = q->info.si_signo;
502 if (likely(q->info.si_code != SI_TIMER)) {
503 sigaddset(&retain, sig);
505 sigdelset(&signal, sig);
506 list_del_init(&q->list);
511 sigorsets(&pending->signal, &signal, &retain);
514 void flush_itimer_signals(void)
516 struct task_struct *tsk = current;
519 spin_lock_irqsave(&tsk->sighand->siglock, flags);
520 __flush_itimer_signals(&tsk->pending);
521 __flush_itimer_signals(&tsk->signal->shared_pending);
522 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
526 void ignore_signals(struct task_struct *t)
530 for (i = 0; i < _NSIG; ++i)
531 t->sighand->action[i].sa.sa_handler = SIG_IGN;
537 * Flush all handlers for a task.
541 flush_signal_handlers(struct task_struct *t, int force_default)
544 struct k_sigaction *ka = &t->sighand->action[0];
545 for (i = _NSIG ; i != 0 ; i--) {
546 if (force_default || ka->sa.sa_handler != SIG_IGN)
547 ka->sa.sa_handler = SIG_DFL;
549 #ifdef __ARCH_HAS_SA_RESTORER
550 ka->sa.sa_restorer = NULL;
552 sigemptyset(&ka->sa.sa_mask);
557 bool unhandled_signal(struct task_struct *tsk, int sig)
559 void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
560 if (is_global_init(tsk))
563 if (handler != SIG_IGN && handler != SIG_DFL)
566 /* If dying, we handle all new signals by ignoring them */
567 if (fatal_signal_pending(tsk))
570 /* if ptraced, let the tracer determine */
574 static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
577 struct sigqueue *q, *first = NULL;
580 * Collect the siginfo appropriate to this signal. Check if
581 * there is another siginfo for the same signal.
583 list_for_each_entry(q, &list->list, list) {
584 if (q->info.si_signo == sig) {
591 sigdelset(&list->signal, sig);
595 list_del_init(&first->list);
596 copy_siginfo(info, &first->info);
599 (first->flags & SIGQUEUE_PREALLOC) &&
600 (info->si_code == SI_TIMER) &&
601 (info->si_sys_private);
603 __sigqueue_free(first);
606 * Ok, it wasn't in the queue. This must be
607 * a fast-pathed signal or we must have been
608 * out of queue space. So zero out the info.
611 info->si_signo = sig;
613 info->si_code = SI_USER;
619 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
620 kernel_siginfo_t *info, bool *resched_timer)
622 int sig = next_signal(pending, mask);
625 collect_signal(sig, pending, info, resched_timer);
630 * Dequeue a signal and return the element to the caller, which is
631 * expected to free it.
633 * All callers have to hold the siglock.
635 int dequeue_signal(struct task_struct *tsk, sigset_t *mask,
636 kernel_siginfo_t *info, enum pid_type *type)
638 bool resched_timer = false;
641 /* We only dequeue private signals from ourselves, we don't let
642 * signalfd steal them
645 signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
647 *type = PIDTYPE_TGID;
648 signr = __dequeue_signal(&tsk->signal->shared_pending,
649 mask, info, &resched_timer);
650 #ifdef CONFIG_POSIX_TIMERS
654 * itimers are process shared and we restart periodic
655 * itimers in the signal delivery path to prevent DoS
656 * attacks in the high resolution timer case. This is
657 * compliant with the old way of self-restarting
658 * itimers, as the SIGALRM is a legacy signal and only
659 * queued once. Changing the restart behaviour to
660 * restart the timer in the signal dequeue path is
661 * reducing the timer noise on heavy loaded !highres
664 if (unlikely(signr == SIGALRM)) {
665 struct hrtimer *tmr = &tsk->signal->real_timer;
667 if (!hrtimer_is_queued(tmr) &&
668 tsk->signal->it_real_incr != 0) {
669 hrtimer_forward(tmr, tmr->base->get_time(),
670 tsk->signal->it_real_incr);
671 hrtimer_restart(tmr);
681 if (unlikely(sig_kernel_stop(signr))) {
683 * Set a marker that we have dequeued a stop signal. Our
684 * caller might release the siglock and then the pending
685 * stop signal it is about to process is no longer in the
686 * pending bitmasks, but must still be cleared by a SIGCONT
687 * (and overruled by a SIGKILL). So those cases clear this
688 * shared flag after we've set it. Note that this flag may
689 * remain set after the signal we return is ignored or
690 * handled. That doesn't matter because its only purpose
691 * is to alert stop-signal processing code when another
692 * processor has come along and cleared the flag.
694 current->jobctl |= JOBCTL_STOP_DEQUEUED;
696 #ifdef CONFIG_POSIX_TIMERS
699 * Release the siglock to ensure proper locking order
700 * of timer locks outside of siglocks. Note, we leave
701 * irqs disabled here, since the posix-timers code is
702 * about to disable them again anyway.
704 spin_unlock(&tsk->sighand->siglock);
705 posixtimer_rearm(info);
706 spin_lock(&tsk->sighand->siglock);
708 /* Don't expose the si_sys_private value to userspace */
709 info->si_sys_private = 0;
714 EXPORT_SYMBOL_GPL(dequeue_signal);
716 static int dequeue_synchronous_signal(kernel_siginfo_t *info)
718 struct task_struct *tsk = current;
719 struct sigpending *pending = &tsk->pending;
720 struct sigqueue *q, *sync = NULL;
723 * Might a synchronous signal be in the queue?
725 if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK))
729 * Return the first synchronous signal in the queue.
731 list_for_each_entry(q, &pending->list, list) {
732 /* Synchronous signals have a positive si_code */
733 if ((q->info.si_code > SI_USER) &&
734 (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK)) {
742 * Check if there is another siginfo for the same signal.
744 list_for_each_entry_continue(q, &pending->list, list) {
745 if (q->info.si_signo == sync->info.si_signo)
749 sigdelset(&pending->signal, sync->info.si_signo);
752 list_del_init(&sync->list);
753 copy_siginfo(info, &sync->info);
754 __sigqueue_free(sync);
755 return info->si_signo;
759 * Tell a process that it has a new active signal..
761 * NOTE! we rely on the previous spin_lock to
762 * lock interrupts for us! We can only be called with
763 * "siglock" held, and the local interrupt must
764 * have been disabled when that got acquired!
766 * No need to set need_resched since signal event passing
767 * goes through ->blocked
769 void signal_wake_up_state(struct task_struct *t, unsigned int state)
771 lockdep_assert_held(&t->sighand->siglock);
773 set_tsk_thread_flag(t, TIF_SIGPENDING);
776 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
777 * case. We don't check t->state here because there is a race with it
778 * executing another processor and just now entering stopped state.
779 * By using wake_up_state, we ensure the process will wake up and
780 * handle its death signal.
782 if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
787 * Remove signals in mask from the pending set and queue.
788 * Returns 1 if any signals were found.
790 * All callers must be holding the siglock.
792 static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
794 struct sigqueue *q, *n;
797 sigandsets(&m, mask, &s->signal);
798 if (sigisemptyset(&m))
801 sigandnsets(&s->signal, &s->signal, mask);
802 list_for_each_entry_safe(q, n, &s->list, list) {
803 if (sigismember(mask, q->info.si_signo)) {
804 list_del_init(&q->list);
810 static inline int is_si_special(const struct kernel_siginfo *info)
812 return info <= SEND_SIG_PRIV;
815 static inline bool si_fromuser(const struct kernel_siginfo *info)
817 return info == SEND_SIG_NOINFO ||
818 (!is_si_special(info) && SI_FROMUSER(info));
822 * called with RCU read lock from check_kill_permission()
824 static bool kill_ok_by_cred(struct task_struct *t)
826 const struct cred *cred = current_cred();
827 const struct cred *tcred = __task_cred(t);
829 return uid_eq(cred->euid, tcred->suid) ||
830 uid_eq(cred->euid, tcred->uid) ||
831 uid_eq(cred->uid, tcred->suid) ||
832 uid_eq(cred->uid, tcred->uid) ||
833 ns_capable(tcred->user_ns, CAP_KILL);
837 * Bad permissions for sending the signal
838 * - the caller must hold the RCU read lock
840 static int check_kill_permission(int sig, struct kernel_siginfo *info,
841 struct task_struct *t)
846 if (!valid_signal(sig))
849 if (!si_fromuser(info))
852 error = audit_signal_info(sig, t); /* Let audit system see the signal */
856 if (!same_thread_group(current, t) &&
857 !kill_ok_by_cred(t)) {
860 sid = task_session(t);
862 * We don't return the error if sid == NULL. The
863 * task was unhashed, the caller must notice this.
865 if (!sid || sid == task_session(current))
873 return security_task_kill(t, info, sig, NULL);
877 * ptrace_trap_notify - schedule trap to notify ptracer
878 * @t: tracee wanting to notify tracer
880 * This function schedules sticky ptrace trap which is cleared on the next
881 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
884 * If @t is running, STOP trap will be taken. If trapped for STOP and
885 * ptracer is listening for events, tracee is woken up so that it can
886 * re-trap for the new event. If trapped otherwise, STOP trap will be
887 * eventually taken without returning to userland after the existing traps
888 * are finished by PTRACE_CONT.
891 * Must be called with @task->sighand->siglock held.
893 static void ptrace_trap_notify(struct task_struct *t)
895 WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
896 lockdep_assert_held(&t->sighand->siglock);
898 task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
899 ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
903 * Handle magic process-wide effects of stop/continue signals. Unlike
904 * the signal actions, these happen immediately at signal-generation
905 * time regardless of blocking, ignoring, or handling. This does the
906 * actual continuing for SIGCONT, but not the actual stopping for stop
907 * signals. The process stop is done as a signal action for SIG_DFL.
909 * Returns true if the signal should be actually delivered, otherwise
910 * it should be dropped.
912 static bool prepare_signal(int sig, struct task_struct *p, bool force)
914 struct signal_struct *signal = p->signal;
915 struct task_struct *t;
918 if (signal->flags & SIGNAL_GROUP_EXIT) {
919 if (signal->core_state)
920 return sig == SIGKILL;
922 * The process is in the middle of dying, drop the signal.
925 } else if (sig_kernel_stop(sig)) {
927 * This is a stop signal. Remove SIGCONT from all queues.
929 siginitset(&flush, sigmask(SIGCONT));
930 flush_sigqueue_mask(&flush, &signal->shared_pending);
931 for_each_thread(p, t)
932 flush_sigqueue_mask(&flush, &t->pending);
933 } else if (sig == SIGCONT) {
936 * Remove all stop signals from all queues, wake all threads.
938 siginitset(&flush, SIG_KERNEL_STOP_MASK);
939 flush_sigqueue_mask(&flush, &signal->shared_pending);
940 for_each_thread(p, t) {
941 flush_sigqueue_mask(&flush, &t->pending);
942 task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
943 if (likely(!(t->ptrace & PT_SEIZED))) {
944 t->jobctl &= ~JOBCTL_STOPPED;
945 wake_up_state(t, __TASK_STOPPED);
947 ptrace_trap_notify(t);
951 * Notify the parent with CLD_CONTINUED if we were stopped.
953 * If we were in the middle of a group stop, we pretend it
954 * was already finished, and then continued. Since SIGCHLD
955 * doesn't queue we report only CLD_STOPPED, as if the next
956 * CLD_CONTINUED was dropped.
959 if (signal->flags & SIGNAL_STOP_STOPPED)
960 why |= SIGNAL_CLD_CONTINUED;
961 else if (signal->group_stop_count)
962 why |= SIGNAL_CLD_STOPPED;
966 * The first thread which returns from do_signal_stop()
967 * will take ->siglock, notice SIGNAL_CLD_MASK, and
968 * notify its parent. See get_signal().
970 signal_set_stop_flags(signal, why | SIGNAL_STOP_CONTINUED);
971 signal->group_stop_count = 0;
972 signal->group_exit_code = 0;
976 return !sig_ignored(p, sig, force);
980 * Test if P wants to take SIG. After we've checked all threads with this,
981 * it's equivalent to finding no threads not blocking SIG. Any threads not
982 * blocking SIG were ruled out because they are not running and already
983 * have pending signals. Such threads will dequeue from the shared queue
984 * as soon as they're available, so putting the signal on the shared queue
985 * will be equivalent to sending it to one such thread.
987 static inline bool wants_signal(int sig, struct task_struct *p)
989 if (sigismember(&p->blocked, sig))
992 if (p->flags & PF_EXITING)
998 if (task_is_stopped_or_traced(p))
1001 return task_curr(p) || !task_sigpending(p);
1004 static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
1006 struct signal_struct *signal = p->signal;
1007 struct task_struct *t;
1010 * Now find a thread we can wake up to take the signal off the queue.
1012 * Try the suggested task first (may or may not be the main thread).
1014 if (wants_signal(sig, p))
1016 else if ((type == PIDTYPE_PID) || thread_group_empty(p))
1018 * There is just one thread and it does not need to be woken.
1019 * It will dequeue unblocked signals before it runs again.
1024 * Otherwise try to find a suitable thread.
1026 t = signal->curr_target;
1027 while (!wants_signal(sig, t)) {
1029 if (t == signal->curr_target)
1031 * No thread needs to be woken.
1032 * Any eligible threads will see
1033 * the signal in the queue soon.
1037 signal->curr_target = t;
1041 * Found a killable thread. If the signal will be fatal,
1042 * then start taking the whole group down immediately.
1044 if (sig_fatal(p, sig) &&
1045 (signal->core_state || !(signal->flags & SIGNAL_GROUP_EXIT)) &&
1046 !sigismember(&t->real_blocked, sig) &&
1047 (sig == SIGKILL || !p->ptrace)) {
1049 * This signal will be fatal to the whole group.
1051 if (!sig_kernel_coredump(sig)) {
1053 * Start a group exit and wake everybody up.
1054 * This way we don't have other threads
1055 * running and doing things after a slower
1056 * thread has the fatal signal pending.
1058 signal->flags = SIGNAL_GROUP_EXIT;
1059 signal->group_exit_code = sig;
1060 signal->group_stop_count = 0;
1063 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1064 sigaddset(&t->pending.signal, SIGKILL);
1065 signal_wake_up(t, 1);
1066 } while_each_thread(p, t);
1072 * The signal is already in the shared-pending queue.
1073 * Tell the chosen thread to wake up and dequeue it.
1075 signal_wake_up(t, sig == SIGKILL);
1079 static inline bool legacy_queue(struct sigpending *signals, int sig)
1081 return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
1084 static int __send_signal_locked(int sig, struct kernel_siginfo *info,
1085 struct task_struct *t, enum pid_type type, bool force)
1087 struct sigpending *pending;
1089 int override_rlimit;
1090 int ret = 0, result;
1092 lockdep_assert_held(&t->sighand->siglock);
1094 result = TRACE_SIGNAL_IGNORED;
1095 if (!prepare_signal(sig, t, force))
1098 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1100 * Short-circuit ignored signals and support queuing
1101 * exactly one non-rt signal, so that we can get more
1102 * detailed information about the cause of the signal.
1104 result = TRACE_SIGNAL_ALREADY_PENDING;
1105 if (legacy_queue(pending, sig))
1108 result = TRACE_SIGNAL_DELIVERED;
1110 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1112 if ((sig == SIGKILL) || (t->flags & PF_KTHREAD))
1116 * Real-time signals must be queued if sent by sigqueue, or
1117 * some other real-time mechanism. It is implementation
1118 * defined whether kill() does so. We attempt to do so, on
1119 * the principle of least surprise, but since kill is not
1120 * allowed to fail with EAGAIN when low on memory we just
1121 * make sure at least one signal gets delivered and don't
1122 * pass on the info struct.
1125 override_rlimit = (is_si_special(info) || info->si_code >= 0);
1127 override_rlimit = 0;
1129 q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
1132 list_add_tail(&q->list, &pending->list);
1133 switch ((unsigned long) info) {
1134 case (unsigned long) SEND_SIG_NOINFO:
1135 clear_siginfo(&q->info);
1136 q->info.si_signo = sig;
1137 q->info.si_errno = 0;
1138 q->info.si_code = SI_USER;
1139 q->info.si_pid = task_tgid_nr_ns(current,
1140 task_active_pid_ns(t));
1143 from_kuid_munged(task_cred_xxx(t, user_ns),
1147 case (unsigned long) SEND_SIG_PRIV:
1148 clear_siginfo(&q->info);
1149 q->info.si_signo = sig;
1150 q->info.si_errno = 0;
1151 q->info.si_code = SI_KERNEL;
1156 copy_siginfo(&q->info, info);
1159 } else if (!is_si_special(info) &&
1160 sig >= SIGRTMIN && info->si_code != SI_USER) {
1162 * Queue overflow, abort. We may abort if the
1163 * signal was rt and sent by user using something
1164 * other than kill().
1166 result = TRACE_SIGNAL_OVERFLOW_FAIL;
1171 * This is a silent loss of information. We still
1172 * send the signal, but the *info bits are lost.
1174 result = TRACE_SIGNAL_LOSE_INFO;
1178 signalfd_notify(t, sig);
1179 sigaddset(&pending->signal, sig);
1181 /* Let multiprocess signals appear after on-going forks */
1182 if (type > PIDTYPE_TGID) {
1183 struct multiprocess_signals *delayed;
1184 hlist_for_each_entry(delayed, &t->signal->multiprocess, node) {
1185 sigset_t *signal = &delayed->signal;
1186 /* Can't queue both a stop and a continue signal */
1188 sigdelsetmask(signal, SIG_KERNEL_STOP_MASK);
1189 else if (sig_kernel_stop(sig))
1190 sigdelset(signal, SIGCONT);
1191 sigaddset(signal, sig);
1195 complete_signal(sig, t, type);
1197 trace_signal_generate(sig, info, t, type != PIDTYPE_PID, result);
1201 static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
1204 switch (siginfo_layout(info->si_signo, info->si_code)) {
1213 case SIL_FAULT_TRAPNO:
1214 case SIL_FAULT_MCEERR:
1215 case SIL_FAULT_BNDERR:
1216 case SIL_FAULT_PKUERR:
1217 case SIL_FAULT_PERF_EVENT:
1225 int send_signal_locked(int sig, struct kernel_siginfo *info,
1226 struct task_struct *t, enum pid_type type)
1228 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1231 if (info == SEND_SIG_NOINFO) {
1232 /* Force if sent from an ancestor pid namespace */
1233 force = !task_pid_nr_ns(current, task_active_pid_ns(t));
1234 } else if (info == SEND_SIG_PRIV) {
1235 /* Don't ignore kernel generated signals */
1237 } else if (has_si_pid_and_uid(info)) {
1238 /* SIGKILL and SIGSTOP is special or has ids */
1239 struct user_namespace *t_user_ns;
1242 t_user_ns = task_cred_xxx(t, user_ns);
1243 if (current_user_ns() != t_user_ns) {
1244 kuid_t uid = make_kuid(current_user_ns(), info->si_uid);
1245 info->si_uid = from_kuid_munged(t_user_ns, uid);
1249 /* A kernel generated signal? */
1250 force = (info->si_code == SI_KERNEL);
1252 /* From an ancestor pid namespace? */
1253 if (!task_pid_nr_ns(current, task_active_pid_ns(t))) {
1258 return __send_signal_locked(sig, info, t, type, force);
1261 static void print_fatal_signal(int signr)
1263 struct pt_regs *regs = task_pt_regs(current);
1264 struct file *exe_file;
1266 exe_file = get_task_exe_file(current);
1268 pr_info("%pD: %s: potentially unexpected fatal signal %d.\n",
1269 exe_file, current->comm, signr);
1272 pr_info("%s: potentially unexpected fatal signal %d.\n",
1273 current->comm, signr);
1276 #if defined(__i386__) && !defined(__arch_um__)
1277 pr_info("code at %08lx: ", regs->ip);
1280 for (i = 0; i < 16; i++) {
1283 if (get_user(insn, (unsigned char *)(regs->ip + i)))
1285 pr_cont("%02x ", insn);
1295 static int __init setup_print_fatal_signals(char *str)
1297 get_option (&str, &print_fatal_signals);
1302 __setup("print-fatal-signals=", setup_print_fatal_signals);
1304 int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
1307 unsigned long flags;
1310 if (lock_task_sighand(p, &flags)) {
1311 ret = send_signal_locked(sig, info, p, type);
1312 unlock_task_sighand(p, &flags);
1319 HANDLER_CURRENT, /* If reachable use the current handler */
1320 HANDLER_SIG_DFL, /* Always use SIG_DFL handler semantics */
1321 HANDLER_EXIT, /* Only visible as the process exit code */
1325 * Force a signal that the process can't ignore: if necessary
1326 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1328 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1329 * since we do not want to have a signal handler that was blocked
1330 * be invoked when user space had explicitly blocked it.
1332 * We don't want to have recursive SIGSEGV's etc, for example,
1333 * that is why we also clear SIGNAL_UNKILLABLE.
1336 force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t,
1337 enum sig_handler handler)
1339 unsigned long int flags;
1340 int ret, blocked, ignored;
1341 struct k_sigaction *action;
1342 int sig = info->si_signo;
1344 spin_lock_irqsave(&t->sighand->siglock, flags);
1345 action = &t->sighand->action[sig-1];
1346 ignored = action->sa.sa_handler == SIG_IGN;
1347 blocked = sigismember(&t->blocked, sig);
1348 if (blocked || ignored || (handler != HANDLER_CURRENT)) {
1349 action->sa.sa_handler = SIG_DFL;
1350 if (handler == HANDLER_EXIT)
1351 action->sa.sa_flags |= SA_IMMUTABLE;
1353 sigdelset(&t->blocked, sig);
1354 recalc_sigpending_and_wake(t);
1358 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1359 * debugging to leave init killable. But HANDLER_EXIT is always fatal.
1361 if (action->sa.sa_handler == SIG_DFL &&
1362 (!t->ptrace || (handler == HANDLER_EXIT)))
1363 t->signal->flags &= ~SIGNAL_UNKILLABLE;
1364 ret = send_signal_locked(sig, info, t, PIDTYPE_PID);
1365 spin_unlock_irqrestore(&t->sighand->siglock, flags);
1370 int force_sig_info(struct kernel_siginfo *info)
1372 return force_sig_info_to_task(info, current, HANDLER_CURRENT);
1376 * Nuke all other threads in the group.
1378 int zap_other_threads(struct task_struct *p)
1380 struct task_struct *t = p;
1383 p->signal->group_stop_count = 0;
1385 while_each_thread(p, t) {
1386 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
1387 /* Don't require de_thread to wait for the vhost_worker */
1388 if ((t->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)
1391 /* Don't bother with already dead threads */
1394 sigaddset(&t->pending.signal, SIGKILL);
1395 signal_wake_up(t, 1);
1401 struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
1402 unsigned long *flags)
1404 struct sighand_struct *sighand;
1408 sighand = rcu_dereference(tsk->sighand);
1409 if (unlikely(sighand == NULL))
1413 * This sighand can be already freed and even reused, but
1414 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1415 * initializes ->siglock: this slab can't go away, it has
1416 * the same object type, ->siglock can't be reinitialized.
1418 * We need to ensure that tsk->sighand is still the same
1419 * after we take the lock, we can race with de_thread() or
1420 * __exit_signal(). In the latter case the next iteration
1421 * must see ->sighand == NULL.
1423 spin_lock_irqsave(&sighand->siglock, *flags);
1424 if (likely(sighand == rcu_access_pointer(tsk->sighand)))
1426 spin_unlock_irqrestore(&sighand->siglock, *flags);
1433 #ifdef CONFIG_LOCKDEP
1434 void lockdep_assert_task_sighand_held(struct task_struct *task)
1436 struct sighand_struct *sighand;
1439 sighand = rcu_dereference(task->sighand);
1441 lockdep_assert_held(&sighand->siglock);
1449 * send signal info to all the members of a group
1451 int group_send_sig_info(int sig, struct kernel_siginfo *info,
1452 struct task_struct *p, enum pid_type type)
1457 ret = check_kill_permission(sig, info, p);
1461 ret = do_send_sig_info(sig, info, p, type);
1467 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1468 * control characters do (^C, ^Z etc)
1469 * - the caller must hold at least a readlock on tasklist_lock
1471 int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
1473 struct task_struct *p = NULL;
1474 int retval, success;
1478 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
1479 int err = group_send_sig_info(sig, info, p, PIDTYPE_PGID);
1482 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
1483 return success ? 0 : retval;
1486 int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
1489 struct task_struct *p;
1493 p = pid_task(pid, PIDTYPE_PID);
1495 error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
1497 if (likely(!p || error != -ESRCH))
1501 * The task was unhashed in between, try again. If it
1502 * is dead, pid_task() will return NULL, if we race with
1503 * de_thread() it will find the new leader.
1508 static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
1512 error = kill_pid_info(sig, info, find_vpid(pid));
1517 static inline bool kill_as_cred_perm(const struct cred *cred,
1518 struct task_struct *target)
1520 const struct cred *pcred = __task_cred(target);
1522 return uid_eq(cred->euid, pcred->suid) ||
1523 uid_eq(cred->euid, pcred->uid) ||
1524 uid_eq(cred->uid, pcred->suid) ||
1525 uid_eq(cred->uid, pcred->uid);
1529 * The usb asyncio usage of siginfo is wrong. The glibc support
1530 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1531 * AKA after the generic fields:
1532 * kernel_pid_t si_pid;
1533 * kernel_uid32_t si_uid;
1534 * sigval_t si_value;
1536 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1537 * after the generic fields is:
1538 * void __user *si_addr;
1540 * This is a practical problem when there is a 64bit big endian kernel
1541 * and a 32bit userspace. As the 32bit address will encoded in the low
1542 * 32bits of the pointer. Those low 32bits will be stored at higher
1543 * address than appear in a 32 bit pointer. So userspace will not
1544 * see the address it was expecting for it's completions.
1546 * There is nothing in the encoding that can allow
1547 * copy_siginfo_to_user32 to detect this confusion of formats, so
1548 * handle this by requiring the caller of kill_pid_usb_asyncio to
1549 * notice when this situration takes place and to store the 32bit
1550 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1553 int kill_pid_usb_asyncio(int sig, int errno, sigval_t addr,
1554 struct pid *pid, const struct cred *cred)
1556 struct kernel_siginfo info;
1557 struct task_struct *p;
1558 unsigned long flags;
1561 if (!valid_signal(sig))
1564 clear_siginfo(&info);
1565 info.si_signo = sig;
1566 info.si_errno = errno;
1567 info.si_code = SI_ASYNCIO;
1568 *((sigval_t *)&info.si_pid) = addr;
1571 p = pid_task(pid, PIDTYPE_PID);
1576 if (!kill_as_cred_perm(cred, p)) {
1580 ret = security_task_kill(p, &info, sig, cred);
1585 if (lock_task_sighand(p, &flags)) {
1586 ret = __send_signal_locked(sig, &info, p, PIDTYPE_TGID, false);
1587 unlock_task_sighand(p, &flags);
1595 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio);
1598 * kill_something_info() interprets pid in interesting ways just like kill(2).
1600 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1601 * is probably wrong. Should make it like BSD or SYSV.
1604 static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
1609 return kill_proc_info(sig, info, pid);
1611 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1615 read_lock(&tasklist_lock);
1617 ret = __kill_pgrp_info(sig, info,
1618 pid ? find_vpid(-pid) : task_pgrp(current));
1620 int retval = 0, count = 0;
1621 struct task_struct * p;
1623 for_each_process(p) {
1624 if (task_pid_vnr(p) > 1 &&
1625 !same_thread_group(p, current)) {
1626 int err = group_send_sig_info(sig, info, p,
1633 ret = count ? retval : -ESRCH;
1635 read_unlock(&tasklist_lock);
1641 * These are for backward compatibility with the rest of the kernel source.
1644 int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
1647 * Make sure legacy kernel users don't send in bad values
1648 * (normal paths check this in check_kill_permission).
1650 if (!valid_signal(sig))
1653 return do_send_sig_info(sig, info, p, PIDTYPE_PID);
1655 EXPORT_SYMBOL(send_sig_info);
1657 #define __si_special(priv) \
1658 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1661 send_sig(int sig, struct task_struct *p, int priv)
1663 return send_sig_info(sig, __si_special(priv), p);
1665 EXPORT_SYMBOL(send_sig);
1667 void force_sig(int sig)
1669 struct kernel_siginfo info;
1671 clear_siginfo(&info);
1672 info.si_signo = sig;
1674 info.si_code = SI_KERNEL;
1677 force_sig_info(&info);
1679 EXPORT_SYMBOL(force_sig);
1681 void force_fatal_sig(int sig)
1683 struct kernel_siginfo info;
1685 clear_siginfo(&info);
1686 info.si_signo = sig;
1688 info.si_code = SI_KERNEL;
1691 force_sig_info_to_task(&info, current, HANDLER_SIG_DFL);
1694 void force_exit_sig(int sig)
1696 struct kernel_siginfo info;
1698 clear_siginfo(&info);
1699 info.si_signo = sig;
1701 info.si_code = SI_KERNEL;
1704 force_sig_info_to_task(&info, current, HANDLER_EXIT);
1708 * When things go south during signal handling, we
1709 * will force a SIGSEGV. And if the signal that caused
1710 * the problem was already a SIGSEGV, we'll want to
1711 * make sure we don't even try to deliver the signal..
1713 void force_sigsegv(int sig)
1716 force_fatal_sig(SIGSEGV);
1721 int force_sig_fault_to_task(int sig, int code, void __user *addr
1722 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1723 , struct task_struct *t)
1725 struct kernel_siginfo info;
1727 clear_siginfo(&info);
1728 info.si_signo = sig;
1730 info.si_code = code;
1731 info.si_addr = addr;
1734 info.si_flags = flags;
1737 return force_sig_info_to_task(&info, t, HANDLER_CURRENT);
1740 int force_sig_fault(int sig, int code, void __user *addr
1741 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr))
1743 return force_sig_fault_to_task(sig, code, addr
1744 ___ARCH_SI_IA64(imm, flags, isr), current);
1747 int send_sig_fault(int sig, int code, void __user *addr
1748 ___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
1749 , struct task_struct *t)
1751 struct kernel_siginfo info;
1753 clear_siginfo(&info);
1754 info.si_signo = sig;
1756 info.si_code = code;
1757 info.si_addr = addr;
1760 info.si_flags = flags;
1763 return send_sig_info(info.si_signo, &info, t);
1766 int force_sig_mceerr(int code, void __user *addr, short lsb)
1768 struct kernel_siginfo info;
1770 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1771 clear_siginfo(&info);
1772 info.si_signo = SIGBUS;
1774 info.si_code = code;
1775 info.si_addr = addr;
1776 info.si_addr_lsb = lsb;
1777 return force_sig_info(&info);
1780 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
1782 struct kernel_siginfo info;
1784 WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
1785 clear_siginfo(&info);
1786 info.si_signo = SIGBUS;
1788 info.si_code = code;
1789 info.si_addr = addr;
1790 info.si_addr_lsb = lsb;
1791 return send_sig_info(info.si_signo, &info, t);
1793 EXPORT_SYMBOL(send_sig_mceerr);
1795 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
1797 struct kernel_siginfo info;
1799 clear_siginfo(&info);
1800 info.si_signo = SIGSEGV;
1802 info.si_code = SEGV_BNDERR;
1803 info.si_addr = addr;
1804 info.si_lower = lower;
1805 info.si_upper = upper;
1806 return force_sig_info(&info);
1810 int force_sig_pkuerr(void __user *addr, u32 pkey)
1812 struct kernel_siginfo info;
1814 clear_siginfo(&info);
1815 info.si_signo = SIGSEGV;
1817 info.si_code = SEGV_PKUERR;
1818 info.si_addr = addr;
1819 info.si_pkey = pkey;
1820 return force_sig_info(&info);
1824 int send_sig_perf(void __user *addr, u32 type, u64 sig_data)
1826 struct kernel_siginfo info;
1828 clear_siginfo(&info);
1829 info.si_signo = SIGTRAP;
1831 info.si_code = TRAP_PERF;
1832 info.si_addr = addr;
1833 info.si_perf_data = sig_data;
1834 info.si_perf_type = type;
1837 * Signals generated by perf events should not terminate the whole
1838 * process if SIGTRAP is blocked, however, delivering the signal
1839 * asynchronously is better than not delivering at all. But tell user
1840 * space if the signal was asynchronous, so it can clearly be
1841 * distinguished from normal synchronous ones.
1843 info.si_perf_flags = sigismember(¤t->blocked, info.si_signo) ?
1844 TRAP_PERF_FLAG_ASYNC :
1847 return send_sig_info(info.si_signo, &info, current);
1851 * force_sig_seccomp - signals the task to allow in-process syscall emulation
1852 * @syscall: syscall number to send to userland
1853 * @reason: filter-supplied reason code to send to userland (via si_errno)
1854 * @force_coredump: true to trigger a coredump
1856 * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
1858 int force_sig_seccomp(int syscall, int reason, bool force_coredump)
1860 struct kernel_siginfo info;
1862 clear_siginfo(&info);
1863 info.si_signo = SIGSYS;
1864 info.si_code = SYS_SECCOMP;
1865 info.si_call_addr = (void __user *)KSTK_EIP(current);
1866 info.si_errno = reason;
1867 info.si_arch = syscall_get_arch(current);
1868 info.si_syscall = syscall;
1869 return force_sig_info_to_task(&info, current,
1870 force_coredump ? HANDLER_EXIT : HANDLER_CURRENT);
1873 /* For the crazy architectures that include trap information in
1874 * the errno field, instead of an actual errno value.
1876 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
1878 struct kernel_siginfo info;
1880 clear_siginfo(&info);
1881 info.si_signo = SIGTRAP;
1882 info.si_errno = errno;
1883 info.si_code = TRAP_HWBKPT;
1884 info.si_addr = addr;
1885 return force_sig_info(&info);
1888 /* For the rare architectures that include trap information using
1891 int force_sig_fault_trapno(int sig, int code, void __user *addr, int trapno)
1893 struct kernel_siginfo info;
1895 clear_siginfo(&info);
1896 info.si_signo = sig;
1898 info.si_code = code;
1899 info.si_addr = addr;
1900 info.si_trapno = trapno;
1901 return force_sig_info(&info);
1904 /* For the rare architectures that include trap information using
1907 int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
1908 struct task_struct *t)
1910 struct kernel_siginfo info;
1912 clear_siginfo(&info);
1913 info.si_signo = sig;
1915 info.si_code = code;
1916 info.si_addr = addr;
1917 info.si_trapno = trapno;
1918 return send_sig_info(info.si_signo, &info, t);
1921 int kill_pgrp(struct pid *pid, int sig, int priv)
1925 read_lock(&tasklist_lock);
1926 ret = __kill_pgrp_info(sig, __si_special(priv), pid);
1927 read_unlock(&tasklist_lock);
1931 EXPORT_SYMBOL(kill_pgrp);
1933 int kill_pid(struct pid *pid, int sig, int priv)
1935 return kill_pid_info(sig, __si_special(priv), pid);
1937 EXPORT_SYMBOL(kill_pid);
1940 * These functions support sending signals using preallocated sigqueue
1941 * structures. This is needed "because realtime applications cannot
1942 * afford to lose notifications of asynchronous events, like timer
1943 * expirations or I/O completions". In the case of POSIX Timers
1944 * we allocate the sigqueue structure from the timer_create. If this
1945 * allocation fails we are able to report the failure to the application
1946 * with an EAGAIN error.
1948 struct sigqueue *sigqueue_alloc(void)
1950 return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
1953 void sigqueue_free(struct sigqueue *q)
1955 unsigned long flags;
1956 spinlock_t *lock = ¤t->sighand->siglock;
1958 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1960 * We must hold ->siglock while testing q->list
1961 * to serialize with collect_signal() or with
1962 * __exit_signal()->flush_sigqueue().
1964 spin_lock_irqsave(lock, flags);
1965 q->flags &= ~SIGQUEUE_PREALLOC;
1967 * If it is queued it will be freed when dequeued,
1968 * like the "regular" sigqueue.
1970 if (!list_empty(&q->list))
1972 spin_unlock_irqrestore(lock, flags);
1978 int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
1980 int sig = q->info.si_signo;
1981 struct sigpending *pending;
1982 struct task_struct *t;
1983 unsigned long flags;
1986 BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
1992 * This function is used by POSIX timers to deliver a timer signal.
1993 * Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID
1994 * set), the signal must be delivered to the specific thread (queues
1997 * Where type is not PIDTYPE_PID, signals must be delivered to the
1998 * process. In this case, prefer to deliver to current if it is in
1999 * the same thread group as the target process, which avoids
2000 * unnecessarily waking up a potentially idle task.
2002 t = pid_task(pid, type);
2005 if (type != PIDTYPE_PID && same_thread_group(t, current))
2007 if (!likely(lock_task_sighand(t, &flags)))
2010 ret = 1; /* the signal is ignored */
2011 result = TRACE_SIGNAL_IGNORED;
2012 if (!prepare_signal(sig, t, false))
2016 if (unlikely(!list_empty(&q->list))) {
2018 * If an SI_TIMER entry is already queue just increment
2019 * the overrun count.
2021 BUG_ON(q->info.si_code != SI_TIMER);
2022 q->info.si_overrun++;
2023 result = TRACE_SIGNAL_ALREADY_PENDING;
2026 q->info.si_overrun = 0;
2028 signalfd_notify(t, sig);
2029 pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
2030 list_add_tail(&q->list, &pending->list);
2031 sigaddset(&pending->signal, sig);
2032 complete_signal(sig, t, type);
2033 result = TRACE_SIGNAL_DELIVERED;
2035 trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
2036 unlock_task_sighand(t, &flags);
2042 static void do_notify_pidfd(struct task_struct *task)
2046 WARN_ON(task->exit_state == 0);
2047 pid = task_pid(task);
2048 wake_up_all(&pid->wait_pidfd);
2052 * Let a parent know about the death of a child.
2053 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
2055 * Returns true if our parent ignored us and so we've switched to
2058 bool do_notify_parent(struct task_struct *tsk, int sig)
2060 struct kernel_siginfo info;
2061 unsigned long flags;
2062 struct sighand_struct *psig;
2063 bool autoreap = false;
2066 WARN_ON_ONCE(sig == -1);
2068 /* do_notify_parent_cldstop should have been called instead. */
2069 WARN_ON_ONCE(task_is_stopped_or_traced(tsk));
2071 WARN_ON_ONCE(!tsk->ptrace &&
2072 (tsk->group_leader != tsk || !thread_group_empty(tsk)));
2074 /* Wake up all pidfd waiters */
2075 do_notify_pidfd(tsk);
2077 if (sig != SIGCHLD) {
2079 * This is only possible if parent == real_parent.
2080 * Check if it has changed security domain.
2082 if (tsk->parent_exec_id != READ_ONCE(tsk->parent->self_exec_id))
2086 clear_siginfo(&info);
2087 info.si_signo = sig;
2090 * We are under tasklist_lock here so our parent is tied to
2091 * us and cannot change.
2093 * task_active_pid_ns will always return the same pid namespace
2094 * until a task passes through release_task.
2096 * write_lock() currently calls preempt_disable() which is the
2097 * same as rcu_read_lock(), but according to Oleg, this is not
2098 * correct to rely on this
2101 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
2102 info.si_uid = from_kuid_munged(task_cred_xxx(tsk->parent, user_ns),
2106 task_cputime(tsk, &utime, &stime);
2107 info.si_utime = nsec_to_clock_t(utime + tsk->signal->utime);
2108 info.si_stime = nsec_to_clock_t(stime + tsk->signal->stime);
2110 info.si_status = tsk->exit_code & 0x7f;
2111 if (tsk->exit_code & 0x80)
2112 info.si_code = CLD_DUMPED;
2113 else if (tsk->exit_code & 0x7f)
2114 info.si_code = CLD_KILLED;
2116 info.si_code = CLD_EXITED;
2117 info.si_status = tsk->exit_code >> 8;
2120 psig = tsk->parent->sighand;
2121 spin_lock_irqsave(&psig->siglock, flags);
2122 if (!tsk->ptrace && sig == SIGCHLD &&
2123 (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
2124 (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
2126 * We are exiting and our parent doesn't care. POSIX.1
2127 * defines special semantics for setting SIGCHLD to SIG_IGN
2128 * or setting the SA_NOCLDWAIT flag: we should be reaped
2129 * automatically and not left for our parent's wait4 call.
2130 * Rather than having the parent do it as a magic kind of
2131 * signal handler, we just set this to tell do_exit that we
2132 * can be cleaned up without becoming a zombie. Note that
2133 * we still call __wake_up_parent in this case, because a
2134 * blocked sys_wait4 might now return -ECHILD.
2136 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
2137 * is implementation-defined: we do (if you don't want
2138 * it, just use SIG_IGN instead).
2141 if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
2145 * Send with __send_signal as si_pid and si_uid are in the
2146 * parent's namespaces.
2148 if (valid_signal(sig) && sig)
2149 __send_signal_locked(sig, &info, tsk->parent, PIDTYPE_TGID, false);
2150 __wake_up_parent(tsk, tsk->parent);
2151 spin_unlock_irqrestore(&psig->siglock, flags);
2157 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2158 * @tsk: task reporting the state change
2159 * @for_ptracer: the notification is for ptracer
2160 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2162 * Notify @tsk's parent that the stopped/continued state has changed. If
2163 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2164 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2167 * Must be called with tasklist_lock at least read locked.
2169 static void do_notify_parent_cldstop(struct task_struct *tsk,
2170 bool for_ptracer, int why)
2172 struct kernel_siginfo info;
2173 unsigned long flags;
2174 struct task_struct *parent;
2175 struct sighand_struct *sighand;
2179 parent = tsk->parent;
2181 tsk = tsk->group_leader;
2182 parent = tsk->real_parent;
2185 clear_siginfo(&info);
2186 info.si_signo = SIGCHLD;
2189 * see comment in do_notify_parent() about the following 4 lines
2192 info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
2193 info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
2196 task_cputime(tsk, &utime, &stime);
2197 info.si_utime = nsec_to_clock_t(utime);
2198 info.si_stime = nsec_to_clock_t(stime);
2203 info.si_status = SIGCONT;
2206 info.si_status = tsk->signal->group_exit_code & 0x7f;
2209 info.si_status = tsk->exit_code & 0x7f;
2215 sighand = parent->sighand;
2216 spin_lock_irqsave(&sighand->siglock, flags);
2217 if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
2218 !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
2219 send_signal_locked(SIGCHLD, &info, parent, PIDTYPE_TGID);
2221 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2223 __wake_up_parent(tsk, parent);
2224 spin_unlock_irqrestore(&sighand->siglock, flags);
2228 * This must be called with current->sighand->siglock held.
2230 * This should be the path for all ptrace stops.
2231 * We always set current->last_siginfo while stopped here.
2232 * That makes it a way to test a stopped process for
2233 * being ptrace-stopped vs being job-control-stopped.
2235 * Returns the signal the ptracer requested the code resume
2236 * with. If the code did not stop because the tracer is gone,
2237 * the stop signal remains unchanged unless clear_code.
2239 static int ptrace_stop(int exit_code, int why, unsigned long message,
2240 kernel_siginfo_t *info)
2241 __releases(¤t->sighand->siglock)
2242 __acquires(¤t->sighand->siglock)
2244 bool gstop_done = false;
2246 if (arch_ptrace_stop_needed()) {
2248 * The arch code has something special to do before a
2249 * ptrace stop. This is allowed to block, e.g. for faults
2250 * on user stack pages. We can't keep the siglock while
2251 * calling arch_ptrace_stop, so we must release it now.
2252 * To preserve proper semantics, we must do this before
2253 * any signal bookkeeping like checking group_stop_count.
2255 spin_unlock_irq(¤t->sighand->siglock);
2257 spin_lock_irq(¤t->sighand->siglock);
2261 * After this point ptrace_signal_wake_up or signal_wake_up
2262 * will clear TASK_TRACED if ptrace_unlink happens or a fatal
2263 * signal comes in. Handle previous ptrace_unlinks and fatal
2264 * signals here to prevent ptrace_stop sleeping in schedule.
2266 if (!current->ptrace || __fatal_signal_pending(current))
2269 set_special_state(TASK_TRACED);
2270 current->jobctl |= JOBCTL_TRACED;
2273 * We're committing to trapping. TRACED should be visible before
2274 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2275 * Also, transition to TRACED and updates to ->jobctl should be
2276 * atomic with respect to siglock and should be done after the arch
2277 * hook as siglock is released and regrabbed across it.
2282 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2284 * set_current_state() smp_wmb();
2286 * wait_task_stopped()
2287 * task_stopped_code()
2288 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2292 current->ptrace_message = message;
2293 current->last_siginfo = info;
2294 current->exit_code = exit_code;
2297 * If @why is CLD_STOPPED, we're trapping to participate in a group
2298 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2299 * across siglock relocks since INTERRUPT was scheduled, PENDING
2300 * could be clear now. We act as if SIGCONT is received after
2301 * TASK_TRACED is entered - ignore it.
2303 if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
2304 gstop_done = task_participate_group_stop(current);
2306 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2307 task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
2308 if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
2309 task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
2311 /* entering a trap, clear TRAPPING */
2312 task_clear_jobctl_trapping(current);
2314 spin_unlock_irq(¤t->sighand->siglock);
2315 read_lock(&tasklist_lock);
2317 * Notify parents of the stop.
2319 * While ptraced, there are two parents - the ptracer and
2320 * the real_parent of the group_leader. The ptracer should
2321 * know about every stop while the real parent is only
2322 * interested in the completion of group stop. The states
2323 * for the two don't interact with each other. Notify
2324 * separately unless they're gonna be duplicates.
2326 if (current->ptrace)
2327 do_notify_parent_cldstop(current, true, why);
2328 if (gstop_done && (!current->ptrace || ptrace_reparented(current)))
2329 do_notify_parent_cldstop(current, false, why);
2332 * The previous do_notify_parent_cldstop() invocation woke ptracer.
2333 * One a PREEMPTION kernel this can result in preemption requirement
2334 * which will be fulfilled after read_unlock() and the ptracer will be
2336 * The ptracer is in wait_task_inactive(, __TASK_TRACED) waiting for
2337 * this task wait in schedule(). If this task gets preempted then it
2338 * remains enqueued on the runqueue. The ptracer will observe this and
2339 * then sleep for a delay of one HZ tick. In the meantime this task
2340 * gets scheduled, enters schedule() and will wait for the ptracer.
2342 * This preemption point is not bad from correctness point of view but
2343 * extends the runtime by one HZ tick time due to the ptracer's sleep.
2344 * The preempt-disable section ensures that there will be no preemption
2345 * between unlock and schedule() and so improving the performance since
2346 * the ptracer has no reason to sleep.
2348 * On PREEMPT_RT locking tasklist_lock does not disable preemption.
2349 * Therefore the task can be preempted (after
2350 * do_notify_parent_cldstop()) before unlocking tasklist_lock so there
2351 * is no benefit in doing this. The optimisation is harmful on
2352 * PEEMPT_RT because the spinlock_t (in cgroup_enter_frozen()) must not
2353 * be acquired with disabled preemption.
2355 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
2357 read_unlock(&tasklist_lock);
2358 cgroup_enter_frozen();
2359 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
2360 preempt_enable_no_resched();
2362 cgroup_leave_frozen(true);
2365 * We are back. Now reacquire the siglock before touching
2366 * last_siginfo, so that we are sure to have synchronized with
2367 * any signal-sending on another CPU that wants to examine it.
2369 spin_lock_irq(¤t->sighand->siglock);
2370 exit_code = current->exit_code;
2371 current->last_siginfo = NULL;
2372 current->ptrace_message = 0;
2373 current->exit_code = 0;
2375 /* LISTENING can be set only during STOP traps, clear it */
2376 current->jobctl &= ~(JOBCTL_LISTENING | JOBCTL_PTRACE_FROZEN);
2379 * Queued signals ignored us while we were stopped for tracing.
2380 * So check for any that we should take before resuming user mode.
2381 * This sets TIF_SIGPENDING, but never clears it.
2383 recalc_sigpending_tsk(current);
2387 static int ptrace_do_notify(int signr, int exit_code, int why, unsigned long message)
2389 kernel_siginfo_t info;
2391 clear_siginfo(&info);
2392 info.si_signo = signr;
2393 info.si_code = exit_code;
2394 info.si_pid = task_pid_vnr(current);
2395 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
2397 /* Let the debugger run. */
2398 return ptrace_stop(exit_code, why, message, &info);
2401 int ptrace_notify(int exit_code, unsigned long message)
2405 BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
2406 if (unlikely(task_work_pending(current)))
2409 spin_lock_irq(¤t->sighand->siglock);
2410 signr = ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED, message);
2411 spin_unlock_irq(¤t->sighand->siglock);
2416 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2417 * @signr: signr causing group stop if initiating
2419 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2420 * and participate in it. If already set, participate in the existing
2421 * group stop. If participated in a group stop (and thus slept), %true is
2422 * returned with siglock released.
2424 * If ptraced, this function doesn't handle stop itself. Instead,
2425 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2426 * untouched. The caller must ensure that INTERRUPT trap handling takes
2427 * places afterwards.
2430 * Must be called with @current->sighand->siglock held, which is released
2434 * %false if group stop is already cancelled or ptrace trap is scheduled.
2435 * %true if participated in group stop.
2437 static bool do_signal_stop(int signr)
2438 __releases(¤t->sighand->siglock)
2440 struct signal_struct *sig = current->signal;
2442 if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
2443 unsigned long gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
2444 struct task_struct *t;
2446 /* signr will be recorded in task->jobctl for retries */
2447 WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
2449 if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
2450 unlikely(sig->flags & SIGNAL_GROUP_EXIT) ||
2451 unlikely(sig->group_exec_task))
2454 * There is no group stop already in progress. We must
2457 * While ptraced, a task may be resumed while group stop is
2458 * still in effect and then receive a stop signal and
2459 * initiate another group stop. This deviates from the
2460 * usual behavior as two consecutive stop signals can't
2461 * cause two group stops when !ptraced. That is why we
2462 * also check !task_is_stopped(t) below.
2464 * The condition can be distinguished by testing whether
2465 * SIGNAL_STOP_STOPPED is already set. Don't generate
2466 * group_exit_code in such case.
2468 * This is not necessary for SIGNAL_STOP_CONTINUED because
2469 * an intervening stop signal is required to cause two
2470 * continued events regardless of ptrace.
2472 if (!(sig->flags & SIGNAL_STOP_STOPPED))
2473 sig->group_exit_code = signr;
2475 sig->group_stop_count = 0;
2477 if (task_set_jobctl_pending(current, signr | gstop))
2478 sig->group_stop_count++;
2481 while_each_thread(current, t) {
2483 * Setting state to TASK_STOPPED for a group
2484 * stop is always done with the siglock held,
2485 * so this check has no races.
2487 if (!task_is_stopped(t) &&
2488 task_set_jobctl_pending(t, signr | gstop)) {
2489 sig->group_stop_count++;
2490 if (likely(!(t->ptrace & PT_SEIZED)))
2491 signal_wake_up(t, 0);
2493 ptrace_trap_notify(t);
2498 if (likely(!current->ptrace)) {
2502 * If there are no other threads in the group, or if there
2503 * is a group stop in progress and we are the last to stop,
2504 * report to the parent.
2506 if (task_participate_group_stop(current))
2507 notify = CLD_STOPPED;
2509 current->jobctl |= JOBCTL_STOPPED;
2510 set_special_state(TASK_STOPPED);
2511 spin_unlock_irq(¤t->sighand->siglock);
2514 * Notify the parent of the group stop completion. Because
2515 * we're not holding either the siglock or tasklist_lock
2516 * here, ptracer may attach inbetween; however, this is for
2517 * group stop and should always be delivered to the real
2518 * parent of the group leader. The new ptracer will get
2519 * its notification when this task transitions into
2523 read_lock(&tasklist_lock);
2524 do_notify_parent_cldstop(current, false, notify);
2525 read_unlock(&tasklist_lock);
2528 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2529 cgroup_enter_frozen();
2534 * While ptraced, group stop is handled by STOP trap.
2535 * Schedule it and let the caller deal with it.
2537 task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
2543 * do_jobctl_trap - take care of ptrace jobctl traps
2545 * When PT_SEIZED, it's used for both group stop and explicit
2546 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2547 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2548 * the stop signal; otherwise, %SIGTRAP.
2550 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2551 * number as exit_code and no siginfo.
2554 * Must be called with @current->sighand->siglock held, which may be
2555 * released and re-acquired before returning with intervening sleep.
2557 static void do_jobctl_trap(void)
2559 struct signal_struct *signal = current->signal;
2560 int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
2562 if (current->ptrace & PT_SEIZED) {
2563 if (!signal->group_stop_count &&
2564 !(signal->flags & SIGNAL_STOP_STOPPED))
2566 WARN_ON_ONCE(!signr);
2567 ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
2570 WARN_ON_ONCE(!signr);
2571 ptrace_stop(signr, CLD_STOPPED, 0, NULL);
2576 * do_freezer_trap - handle the freezer jobctl trap
2578 * Puts the task into frozen state, if only the task is not about to quit.
2579 * In this case it drops JOBCTL_TRAP_FREEZE.
2582 * Must be called with @current->sighand->siglock held,
2583 * which is always released before returning.
2585 static void do_freezer_trap(void)
2586 __releases(¤t->sighand->siglock)
2589 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2590 * let's make another loop to give it a chance to be handled.
2591 * In any case, we'll return back.
2593 if ((current->jobctl & (JOBCTL_PENDING_MASK | JOBCTL_TRAP_FREEZE)) !=
2594 JOBCTL_TRAP_FREEZE) {
2595 spin_unlock_irq(¤t->sighand->siglock);
2600 * Now we're sure that there is no pending fatal signal and no
2601 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2602 * immediately (if there is a non-fatal signal pending), and
2603 * put the task into sleep.
2605 __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
2606 clear_thread_flag(TIF_SIGPENDING);
2607 spin_unlock_irq(¤t->sighand->siglock);
2608 cgroup_enter_frozen();
2612 static int ptrace_signal(int signr, kernel_siginfo_t *info, enum pid_type type)
2615 * We do not check sig_kernel_stop(signr) but set this marker
2616 * unconditionally because we do not know whether debugger will
2617 * change signr. This flag has no meaning unless we are going
2618 * to stop after return from ptrace_stop(). In this case it will
2619 * be checked in do_signal_stop(), we should only stop if it was
2620 * not cleared by SIGCONT while we were sleeping. See also the
2621 * comment in dequeue_signal().
2623 current->jobctl |= JOBCTL_STOP_DEQUEUED;
2624 signr = ptrace_stop(signr, CLD_TRAPPED, 0, info);
2626 /* We're back. Did the debugger cancel the sig? */
2631 * Update the siginfo structure if the signal has
2632 * changed. If the debugger wanted something
2633 * specific in the siginfo structure then it should
2634 * have updated *info via PTRACE_SETSIGINFO.
2636 if (signr != info->si_signo) {
2637 clear_siginfo(info);
2638 info->si_signo = signr;
2640 info->si_code = SI_USER;
2642 info->si_pid = task_pid_vnr(current->parent);
2643 info->si_uid = from_kuid_munged(current_user_ns(),
2644 task_uid(current->parent));
2648 /* If the (new) signal is now blocked, requeue it. */
2649 if (sigismember(¤t->blocked, signr) ||
2650 fatal_signal_pending(current)) {
2651 send_signal_locked(signr, info, current, type);
2658 static void hide_si_addr_tag_bits(struct ksignal *ksig)
2660 switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
2662 case SIL_FAULT_TRAPNO:
2663 case SIL_FAULT_MCEERR:
2664 case SIL_FAULT_BNDERR:
2665 case SIL_FAULT_PKUERR:
2666 case SIL_FAULT_PERF_EVENT:
2667 ksig->info.si_addr = arch_untagged_si_addr(
2668 ksig->info.si_addr, ksig->sig, ksig->info.si_code);
2680 bool get_signal(struct ksignal *ksig)
2682 struct sighand_struct *sighand = current->sighand;
2683 struct signal_struct *signal = current->signal;
2686 clear_notify_signal();
2687 if (unlikely(task_work_pending(current)))
2690 if (!task_sigpending(current))
2693 if (unlikely(uprobe_deny_signal()))
2697 * Do this once, we can't return to user-mode if freezing() == T.
2698 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2699 * thus do not need another check after return.
2704 spin_lock_irq(&sighand->siglock);
2707 * Every stopped thread goes here after wakeup. Check to see if
2708 * we should notify the parent, prepare_signal(SIGCONT) encodes
2709 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2711 if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
2714 if (signal->flags & SIGNAL_CLD_CONTINUED)
2715 why = CLD_CONTINUED;
2719 signal->flags &= ~SIGNAL_CLD_MASK;
2721 spin_unlock_irq(&sighand->siglock);
2724 * Notify the parent that we're continuing. This event is
2725 * always per-process and doesn't make whole lot of sense
2726 * for ptracers, who shouldn't consume the state via
2727 * wait(2) either, but, for backward compatibility, notify
2728 * the ptracer of the group leader too unless it's gonna be
2731 read_lock(&tasklist_lock);
2732 do_notify_parent_cldstop(current, false, why);
2734 if (ptrace_reparented(current->group_leader))
2735 do_notify_parent_cldstop(current->group_leader,
2737 read_unlock(&tasklist_lock);
2743 struct k_sigaction *ka;
2746 /* Has this task already been marked for death? */
2747 if ((signal->flags & SIGNAL_GROUP_EXIT) ||
2748 signal->group_exec_task) {
2749 clear_siginfo(&ksig->info);
2750 ksig->info.si_signo = signr = SIGKILL;
2751 sigdelset(¤t->pending.signal, SIGKILL);
2752 trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
2753 &sighand->action[SIGKILL - 1]);
2754 recalc_sigpending();
2758 if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
2762 if (unlikely(current->jobctl &
2763 (JOBCTL_TRAP_MASK | JOBCTL_TRAP_FREEZE))) {
2764 if (current->jobctl & JOBCTL_TRAP_MASK) {
2766 spin_unlock_irq(&sighand->siglock);
2767 } else if (current->jobctl & JOBCTL_TRAP_FREEZE)
2774 * If the task is leaving the frozen state, let's update
2775 * cgroup counters and reset the frozen bit.
2777 if (unlikely(cgroup_task_frozen(current))) {
2778 spin_unlock_irq(&sighand->siglock);
2779 cgroup_leave_frozen(false);
2784 * Signals generated by the execution of an instruction
2785 * need to be delivered before any other pending signals
2786 * so that the instruction pointer in the signal stack
2787 * frame points to the faulting instruction.
2790 signr = dequeue_synchronous_signal(&ksig->info);
2792 signr = dequeue_signal(current, ¤t->blocked,
2793 &ksig->info, &type);
2796 break; /* will return 0 */
2798 if (unlikely(current->ptrace) && (signr != SIGKILL) &&
2799 !(sighand->action[signr -1].sa.sa_flags & SA_IMMUTABLE)) {
2800 signr = ptrace_signal(signr, &ksig->info, type);
2805 ka = &sighand->action[signr-1];
2807 /* Trace actually delivered signals. */
2808 trace_signal_deliver(signr, &ksig->info, ka);
2810 if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
2812 if (ka->sa.sa_handler != SIG_DFL) {
2813 /* Run the handler. */
2816 if (ka->sa.sa_flags & SA_ONESHOT)
2817 ka->sa.sa_handler = SIG_DFL;
2819 break; /* will return non-zero "signr" value */
2823 * Now we are doing the default action for this signal.
2825 if (sig_kernel_ignore(signr)) /* Default is nothing. */
2829 * Global init gets no signals it doesn't want.
2830 * Container-init gets no signals it doesn't want from same
2833 * Note that if global/container-init sees a sig_kernel_only()
2834 * signal here, the signal must have been generated internally
2835 * or must have come from an ancestor namespace. In either
2836 * case, the signal cannot be dropped.
2838 if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
2839 !sig_kernel_only(signr))
2842 if (sig_kernel_stop(signr)) {
2844 * The default action is to stop all threads in
2845 * the thread group. The job control signals
2846 * do nothing in an orphaned pgrp, but SIGSTOP
2847 * always works. Note that siglock needs to be
2848 * dropped during the call to is_orphaned_pgrp()
2849 * because of lock ordering with tasklist_lock.
2850 * This allows an intervening SIGCONT to be posted.
2851 * We need to check for that and bail out if necessary.
2853 if (signr != SIGSTOP) {
2854 spin_unlock_irq(&sighand->siglock);
2856 /* signals can be posted during this window */
2858 if (is_current_pgrp_orphaned())
2861 spin_lock_irq(&sighand->siglock);
2864 if (likely(do_signal_stop(ksig->info.si_signo))) {
2865 /* It released the siglock. */
2870 * We didn't actually stop, due to a race
2871 * with SIGCONT or something like that.
2877 spin_unlock_irq(&sighand->siglock);
2878 if (unlikely(cgroup_task_frozen(current)))
2879 cgroup_leave_frozen(true);
2882 * Anything else is fatal, maybe with a core dump.
2884 current->flags |= PF_SIGNALED;
2886 if (sig_kernel_coredump(signr)) {
2887 if (print_fatal_signals)
2888 print_fatal_signal(ksig->info.si_signo);
2889 proc_coredump_connector(current);
2891 * If it was able to dump core, this kills all
2892 * other threads in the group and synchronizes with
2893 * their demise. If we lost the race with another
2894 * thread getting here, it set group_exit_code
2895 * first and our do_group_exit call below will use
2896 * that value and ignore the one we pass it.
2898 do_coredump(&ksig->info);
2902 * PF_USER_WORKER threads will catch and exit on fatal signals
2903 * themselves. They have cleanup that must be performed, so
2904 * we cannot call do_exit() on their behalf.
2906 if (current->flags & PF_USER_WORKER)
2910 * Death signals, no core dump.
2912 do_group_exit(ksig->info.si_signo);
2915 spin_unlock_irq(&sighand->siglock);
2919 if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
2920 hide_si_addr_tag_bits(ksig);
2922 return ksig->sig > 0;
2926 * signal_delivered - called after signal delivery to update blocked signals
2927 * @ksig: kernel signal struct
2928 * @stepping: nonzero if debugger single-step or block-step in use
2930 * This function should be called when a signal has successfully been
2931 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2932 * is always blocked), and the signal itself is blocked unless %SA_NODEFER
2933 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2935 static void signal_delivered(struct ksignal *ksig, int stepping)
2939 /* A signal was successfully delivered, and the
2940 saved sigmask was stored on the signal frame,
2941 and will be restored by sigreturn. So we can
2942 simply clear the restore sigmask flag. */
2943 clear_restore_sigmask();
2945 sigorsets(&blocked, ¤t->blocked, &ksig->ka.sa.sa_mask);
2946 if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
2947 sigaddset(&blocked, ksig->sig);
2948 set_current_blocked(&blocked);
2949 if (current->sas_ss_flags & SS_AUTODISARM)
2950 sas_ss_reset(current);
2952 ptrace_notify(SIGTRAP, 0);
2955 void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
2958 force_sigsegv(ksig->sig);
2960 signal_delivered(ksig, stepping);
2964 * It could be that complete_signal() picked us to notify about the
2965 * group-wide signal. Other threads should be notified now to take
2966 * the shared signals in @which since we will not.
2968 static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
2971 struct task_struct *t;
2973 sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
2974 if (sigisemptyset(&retarget))
2978 while_each_thread(tsk, t) {
2979 if (t->flags & PF_EXITING)
2982 if (!has_pending_signals(&retarget, &t->blocked))
2984 /* Remove the signals this thread can handle. */
2985 sigandsets(&retarget, &retarget, &t->blocked);
2987 if (!task_sigpending(t))
2988 signal_wake_up(t, 0);
2990 if (sigisemptyset(&retarget))
2995 void exit_signals(struct task_struct *tsk)
3001 * @tsk is about to have PF_EXITING set - lock out users which
3002 * expect stable threadgroup.
3004 cgroup_threadgroup_change_begin(tsk);
3006 if (thread_group_empty(tsk) || (tsk->signal->flags & SIGNAL_GROUP_EXIT)) {
3007 sched_mm_cid_exit_signals(tsk);
3008 tsk->flags |= PF_EXITING;
3009 cgroup_threadgroup_change_end(tsk);
3013 spin_lock_irq(&tsk->sighand->siglock);
3015 * From now this task is not visible for group-wide signals,
3016 * see wants_signal(), do_signal_stop().
3018 sched_mm_cid_exit_signals(tsk);
3019 tsk->flags |= PF_EXITING;
3021 cgroup_threadgroup_change_end(tsk);
3023 if (!task_sigpending(tsk))
3026 unblocked = tsk->blocked;
3027 signotset(&unblocked);
3028 retarget_shared_pending(tsk, &unblocked);
3030 if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
3031 task_participate_group_stop(tsk))
3032 group_stop = CLD_STOPPED;
3034 spin_unlock_irq(&tsk->sighand->siglock);
3037 * If group stop has completed, deliver the notification. This
3038 * should always go to the real parent of the group leader.
3040 if (unlikely(group_stop)) {
3041 read_lock(&tasklist_lock);
3042 do_notify_parent_cldstop(tsk, false, group_stop);
3043 read_unlock(&tasklist_lock);
3048 * System call entry points.
3052 * sys_restart_syscall - restart a system call
3054 SYSCALL_DEFINE0(restart_syscall)
3056 struct restart_block *restart = ¤t->restart_block;
3057 return restart->fn(restart);
3060 long do_no_restart_syscall(struct restart_block *param)
3065 static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
3067 if (task_sigpending(tsk) && !thread_group_empty(tsk)) {
3068 sigset_t newblocked;
3069 /* A set of now blocked but previously unblocked signals. */
3070 sigandnsets(&newblocked, newset, ¤t->blocked);
3071 retarget_shared_pending(tsk, &newblocked);
3073 tsk->blocked = *newset;
3074 recalc_sigpending();
3078 * set_current_blocked - change current->blocked mask
3081 * It is wrong to change ->blocked directly, this helper should be used
3082 * to ensure the process can't miss a shared signal we are going to block.
3084 void set_current_blocked(sigset_t *newset)
3086 sigdelsetmask(newset, sigmask(SIGKILL) | sigmask(SIGSTOP));
3087 __set_current_blocked(newset);
3090 void __set_current_blocked(const sigset_t *newset)
3092 struct task_struct *tsk = current;
3095 * In case the signal mask hasn't changed, there is nothing we need
3096 * to do. The current->blocked shouldn't be modified by other task.
3098 if (sigequalsets(&tsk->blocked, newset))
3101 spin_lock_irq(&tsk->sighand->siglock);
3102 __set_task_blocked(tsk, newset);
3103 spin_unlock_irq(&tsk->sighand->siglock);
3107 * This is also useful for kernel threads that want to temporarily
3108 * (or permanently) block certain signals.
3110 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
3111 * interface happily blocks "unblockable" signals like SIGKILL
3114 int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
3116 struct task_struct *tsk = current;
3119 /* Lockless, only current can change ->blocked, never from irq */
3121 *oldset = tsk->blocked;
3125 sigorsets(&newset, &tsk->blocked, set);
3128 sigandnsets(&newset, &tsk->blocked, set);
3137 __set_current_blocked(&newset);
3140 EXPORT_SYMBOL(sigprocmask);
3143 * The api helps set app-provided sigmasks.
3145 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
3146 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
3148 * Note that it does set_restore_sigmask() in advance, so it must be always
3149 * paired with restore_saved_sigmask_unless() before return from syscall.
3151 int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
3157 if (sigsetsize != sizeof(sigset_t))
3159 if (copy_from_user(&kmask, umask, sizeof(sigset_t)))
3162 set_restore_sigmask();
3163 current->saved_sigmask = current->blocked;
3164 set_current_blocked(&kmask);
3169 #ifdef CONFIG_COMPAT
3170 int set_compat_user_sigmask(const compat_sigset_t __user *umask,
3177 if (sigsetsize != sizeof(compat_sigset_t))
3179 if (get_compat_sigset(&kmask, umask))
3182 set_restore_sigmask();
3183 current->saved_sigmask = current->blocked;
3184 set_current_blocked(&kmask);
3191 * sys_rt_sigprocmask - change the list of currently blocked signals
3192 * @how: whether to add, remove, or set signals
3193 * @nset: stores pending signals
3194 * @oset: previous value of signal mask if non-null
3195 * @sigsetsize: size of sigset_t type
3197 SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
3198 sigset_t __user *, oset, size_t, sigsetsize)
3200 sigset_t old_set, new_set;
3203 /* XXX: Don't preclude handling different sized sigset_t's. */
3204 if (sigsetsize != sizeof(sigset_t))
3207 old_set = current->blocked;
3210 if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
3212 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3214 error = sigprocmask(how, &new_set, NULL);
3220 if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
3227 #ifdef CONFIG_COMPAT
3228 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
3229 compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
3231 sigset_t old_set = current->blocked;
3233 /* XXX: Don't preclude handling different sized sigset_t's. */
3234 if (sigsetsize != sizeof(sigset_t))
3240 if (get_compat_sigset(&new_set, nset))
3242 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
3244 error = sigprocmask(how, &new_set, NULL);
3248 return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
3252 static void do_sigpending(sigset_t *set)
3254 spin_lock_irq(¤t->sighand->siglock);
3255 sigorsets(set, ¤t->pending.signal,
3256 ¤t->signal->shared_pending.signal);
3257 spin_unlock_irq(¤t->sighand->siglock);
3259 /* Outside the lock because only this thread touches it. */
3260 sigandsets(set, ¤t->blocked, set);
3264 * sys_rt_sigpending - examine a pending signal that has been raised
3266 * @uset: stores pending signals
3267 * @sigsetsize: size of sigset_t type or larger
3269 SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
3273 if (sigsetsize > sizeof(*uset))
3276 do_sigpending(&set);
3278 if (copy_to_user(uset, &set, sigsetsize))
3284 #ifdef CONFIG_COMPAT
3285 COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
3286 compat_size_t, sigsetsize)
3290 if (sigsetsize > sizeof(*uset))
3293 do_sigpending(&set);
3295 return put_compat_sigset(uset, &set, sigsetsize);
3299 static const struct {
3300 unsigned char limit, layout;
3302 [SIGILL] = { NSIGILL, SIL_FAULT },
3303 [SIGFPE] = { NSIGFPE, SIL_FAULT },
3304 [SIGSEGV] = { NSIGSEGV, SIL_FAULT },
3305 [SIGBUS] = { NSIGBUS, SIL_FAULT },
3306 [SIGTRAP] = { NSIGTRAP, SIL_FAULT },
3308 [SIGEMT] = { NSIGEMT, SIL_FAULT },
3310 [SIGCHLD] = { NSIGCHLD, SIL_CHLD },
3311 [SIGPOLL] = { NSIGPOLL, SIL_POLL },
3312 [SIGSYS] = { NSIGSYS, SIL_SYS },
3315 static bool known_siginfo_layout(unsigned sig, int si_code)
3317 if (si_code == SI_KERNEL)
3319 else if ((si_code > SI_USER)) {
3320 if (sig_specific_sicodes(sig)) {
3321 if (si_code <= sig_sicodes[sig].limit)
3324 else if (si_code <= NSIGPOLL)
3327 else if (si_code >= SI_DETHREAD)
3329 else if (si_code == SI_ASYNCNL)
3334 enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
3336 enum siginfo_layout layout = SIL_KILL;
3337 if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
3338 if ((sig < ARRAY_SIZE(sig_sicodes)) &&
3339 (si_code <= sig_sicodes[sig].limit)) {
3340 layout = sig_sicodes[sig].layout;
3341 /* Handle the exceptions */
3342 if ((sig == SIGBUS) &&
3343 (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
3344 layout = SIL_FAULT_MCEERR;
3345 else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
3346 layout = SIL_FAULT_BNDERR;
3348 else if ((sig == SIGSEGV) && (si_code == SEGV_PKUERR))
3349 layout = SIL_FAULT_PKUERR;
3351 else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
3352 layout = SIL_FAULT_PERF_EVENT;
3353 else if (IS_ENABLED(CONFIG_SPARC) &&
3354 (sig == SIGILL) && (si_code == ILL_ILLTRP))
3355 layout = SIL_FAULT_TRAPNO;
3356 else if (IS_ENABLED(CONFIG_ALPHA) &&
3358 ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
3359 layout = SIL_FAULT_TRAPNO;
3361 else if (si_code <= NSIGPOLL)
3364 if (si_code == SI_TIMER)
3366 else if (si_code == SI_SIGIO)
3368 else if (si_code < 0)
3374 static inline char __user *si_expansion(const siginfo_t __user *info)
3376 return ((char __user *)info) + sizeof(struct kernel_siginfo);
3379 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
3381 char __user *expansion = si_expansion(to);
3382 if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
3384 if (clear_user(expansion, SI_EXPANSION_SIZE))
3389 static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
3390 const siginfo_t __user *from)
3392 if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
3393 char __user *expansion = si_expansion(from);
3394 char buf[SI_EXPANSION_SIZE];
3397 * An unknown si_code might need more than
3398 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3399 * extra bytes are 0. This guarantees copy_siginfo_to_user
3400 * will return this data to userspace exactly.
3402 if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
3404 for (i = 0; i < SI_EXPANSION_SIZE; i++) {
3412 static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
3413 const siginfo_t __user *from)
3415 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3417 to->si_signo = signo;
3418 return post_copy_siginfo_from_user(to, from);
3421 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
3423 if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
3425 return post_copy_siginfo_from_user(to, from);
3428 #ifdef CONFIG_COMPAT
3430 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3431 * @to: compat siginfo destination
3432 * @from: kernel siginfo source
3434 * Note: This function does not work properly for the SIGCHLD on x32, but
3435 * fortunately it doesn't have to. The only valid callers for this function are
3436 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3437 * The latter does not care because SIGCHLD will never cause a coredump.
3439 void copy_siginfo_to_external32(struct compat_siginfo *to,
3440 const struct kernel_siginfo *from)
3442 memset(to, 0, sizeof(*to));
3444 to->si_signo = from->si_signo;
3445 to->si_errno = from->si_errno;
3446 to->si_code = from->si_code;
3447 switch(siginfo_layout(from->si_signo, from->si_code)) {
3449 to->si_pid = from->si_pid;
3450 to->si_uid = from->si_uid;
3453 to->si_tid = from->si_tid;
3454 to->si_overrun = from->si_overrun;
3455 to->si_int = from->si_int;
3458 to->si_band = from->si_band;
3459 to->si_fd = from->si_fd;
3462 to->si_addr = ptr_to_compat(from->si_addr);
3464 case SIL_FAULT_TRAPNO:
3465 to->si_addr = ptr_to_compat(from->si_addr);
3466 to->si_trapno = from->si_trapno;
3468 case SIL_FAULT_MCEERR:
3469 to->si_addr = ptr_to_compat(from->si_addr);
3470 to->si_addr_lsb = from->si_addr_lsb;
3472 case SIL_FAULT_BNDERR:
3473 to->si_addr = ptr_to_compat(from->si_addr);
3474 to->si_lower = ptr_to_compat(from->si_lower);
3475 to->si_upper = ptr_to_compat(from->si_upper);
3477 case SIL_FAULT_PKUERR:
3478 to->si_addr = ptr_to_compat(from->si_addr);
3479 to->si_pkey = from->si_pkey;
3481 case SIL_FAULT_PERF_EVENT:
3482 to->si_addr = ptr_to_compat(from->si_addr);
3483 to->si_perf_data = from->si_perf_data;
3484 to->si_perf_type = from->si_perf_type;
3485 to->si_perf_flags = from->si_perf_flags;
3488 to->si_pid = from->si_pid;
3489 to->si_uid = from->si_uid;
3490 to->si_status = from->si_status;
3491 to->si_utime = from->si_utime;
3492 to->si_stime = from->si_stime;
3495 to->si_pid = from->si_pid;
3496 to->si_uid = from->si_uid;
3497 to->si_int = from->si_int;
3500 to->si_call_addr = ptr_to_compat(from->si_call_addr);
3501 to->si_syscall = from->si_syscall;
3502 to->si_arch = from->si_arch;
3507 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
3508 const struct kernel_siginfo *from)
3510 struct compat_siginfo new;
3512 copy_siginfo_to_external32(&new, from);
3513 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
3518 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
3519 const struct compat_siginfo *from)
3522 to->si_signo = from->si_signo;
3523 to->si_errno = from->si_errno;
3524 to->si_code = from->si_code;
3525 switch(siginfo_layout(from->si_signo, from->si_code)) {
3527 to->si_pid = from->si_pid;
3528 to->si_uid = from->si_uid;
3531 to->si_tid = from->si_tid;
3532 to->si_overrun = from->si_overrun;
3533 to->si_int = from->si_int;
3536 to->si_band = from->si_band;
3537 to->si_fd = from->si_fd;
3540 to->si_addr = compat_ptr(from->si_addr);
3542 case SIL_FAULT_TRAPNO:
3543 to->si_addr = compat_ptr(from->si_addr);
3544 to->si_trapno = from->si_trapno;
3546 case SIL_FAULT_MCEERR:
3547 to->si_addr = compat_ptr(from->si_addr);
3548 to->si_addr_lsb = from->si_addr_lsb;
3550 case SIL_FAULT_BNDERR:
3551 to->si_addr = compat_ptr(from->si_addr);
3552 to->si_lower = compat_ptr(from->si_lower);
3553 to->si_upper = compat_ptr(from->si_upper);
3555 case SIL_FAULT_PKUERR:
3556 to->si_addr = compat_ptr(from->si_addr);
3557 to->si_pkey = from->si_pkey;
3559 case SIL_FAULT_PERF_EVENT:
3560 to->si_addr = compat_ptr(from->si_addr);
3561 to->si_perf_data = from->si_perf_data;
3562 to->si_perf_type = from->si_perf_type;
3563 to->si_perf_flags = from->si_perf_flags;
3566 to->si_pid = from->si_pid;
3567 to->si_uid = from->si_uid;
3568 to->si_status = from->si_status;
3569 #ifdef CONFIG_X86_X32_ABI
3570 if (in_x32_syscall()) {
3571 to->si_utime = from->_sifields._sigchld_x32._utime;
3572 to->si_stime = from->_sifields._sigchld_x32._stime;
3576 to->si_utime = from->si_utime;
3577 to->si_stime = from->si_stime;
3581 to->si_pid = from->si_pid;
3582 to->si_uid = from->si_uid;
3583 to->si_int = from->si_int;
3586 to->si_call_addr = compat_ptr(from->si_call_addr);
3587 to->si_syscall = from->si_syscall;
3588 to->si_arch = from->si_arch;
3594 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
3595 const struct compat_siginfo __user *ufrom)
3597 struct compat_siginfo from;
3599 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3602 from.si_signo = signo;
3603 return post_copy_siginfo_from_user32(to, &from);
3606 int copy_siginfo_from_user32(struct kernel_siginfo *to,
3607 const struct compat_siginfo __user *ufrom)
3609 struct compat_siginfo from;
3611 if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
3614 return post_copy_siginfo_from_user32(to, &from);
3616 #endif /* CONFIG_COMPAT */
3619 * do_sigtimedwait - wait for queued signals specified in @which
3620 * @which: queued signals to wait for
3621 * @info: if non-null, the signal's siginfo is returned here
3622 * @ts: upper bound on process time suspension
3624 static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
3625 const struct timespec64 *ts)
3627 ktime_t *to = NULL, timeout = KTIME_MAX;
3628 struct task_struct *tsk = current;
3629 sigset_t mask = *which;
3634 if (!timespec64_valid(ts))
3636 timeout = timespec64_to_ktime(*ts);
3641 * Invert the set of allowed signals to get those we want to block.
3643 sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
3646 spin_lock_irq(&tsk->sighand->siglock);
3647 sig = dequeue_signal(tsk, &mask, info, &type);
3648 if (!sig && timeout) {
3650 * None ready, temporarily unblock those we're interested
3651 * while we are sleeping in so that we'll be awakened when
3652 * they arrive. Unblocking is always fine, we can avoid
3653 * set_current_blocked().
3655 tsk->real_blocked = tsk->blocked;
3656 sigandsets(&tsk->blocked, &tsk->blocked, &mask);
3657 recalc_sigpending();
3658 spin_unlock_irq(&tsk->sighand->siglock);
3660 __set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
3661 ret = schedule_hrtimeout_range(to, tsk->timer_slack_ns,
3663 spin_lock_irq(&tsk->sighand->siglock);
3664 __set_task_blocked(tsk, &tsk->real_blocked);
3665 sigemptyset(&tsk->real_blocked);
3666 sig = dequeue_signal(tsk, &mask, info, &type);
3668 spin_unlock_irq(&tsk->sighand->siglock);
3672 return ret ? -EINTR : -EAGAIN;
3676 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3678 * @uthese: queued signals to wait for
3679 * @uinfo: if non-null, the signal's siginfo is returned here
3680 * @uts: upper bound on process time suspension
3681 * @sigsetsize: size of sigset_t type
3683 SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
3684 siginfo_t __user *, uinfo,
3685 const struct __kernel_timespec __user *, uts,
3689 struct timespec64 ts;
3690 kernel_siginfo_t info;
3693 /* XXX: Don't preclude handling different sized sigset_t's. */
3694 if (sigsetsize != sizeof(sigset_t))
3697 if (copy_from_user(&these, uthese, sizeof(these)))
3701 if (get_timespec64(&ts, uts))
3705 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3707 if (ret > 0 && uinfo) {
3708 if (copy_siginfo_to_user(uinfo, &info))
3715 #ifdef CONFIG_COMPAT_32BIT_TIME
3716 SYSCALL_DEFINE4(rt_sigtimedwait_time32, const sigset_t __user *, uthese,
3717 siginfo_t __user *, uinfo,
3718 const struct old_timespec32 __user *, uts,
3722 struct timespec64 ts;
3723 kernel_siginfo_t info;
3726 if (sigsetsize != sizeof(sigset_t))
3729 if (copy_from_user(&these, uthese, sizeof(these)))
3733 if (get_old_timespec32(&ts, uts))
3737 ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
3739 if (ret > 0 && uinfo) {
3740 if (copy_siginfo_to_user(uinfo, &info))
3748 #ifdef CONFIG_COMPAT
3749 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64, compat_sigset_t __user *, uthese,
3750 struct compat_siginfo __user *, uinfo,
3751 struct __kernel_timespec __user *, uts, compat_size_t, sigsetsize)
3754 struct timespec64 t;
3755 kernel_siginfo_t info;
3758 if (sigsetsize != sizeof(sigset_t))
3761 if (get_compat_sigset(&s, uthese))
3765 if (get_timespec64(&t, uts))
3769 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3771 if (ret > 0 && uinfo) {
3772 if (copy_siginfo_to_user32(uinfo, &info))
3779 #ifdef CONFIG_COMPAT_32BIT_TIME
3780 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
3781 struct compat_siginfo __user *, uinfo,
3782 struct old_timespec32 __user *, uts, compat_size_t, sigsetsize)
3785 struct timespec64 t;
3786 kernel_siginfo_t info;
3789 if (sigsetsize != sizeof(sigset_t))
3792 if (get_compat_sigset(&s, uthese))
3796 if (get_old_timespec32(&t, uts))
3800 ret = do_sigtimedwait(&s, &info, uts ? &t : NULL);
3802 if (ret > 0 && uinfo) {
3803 if (copy_siginfo_to_user32(uinfo, &info))
3812 static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
3814 clear_siginfo(info);
3815 info->si_signo = sig;
3817 info->si_code = SI_USER;
3818 info->si_pid = task_tgid_vnr(current);
3819 info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
3823 * sys_kill - send a signal to a process
3824 * @pid: the PID of the process
3825 * @sig: signal to be sent
3827 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
3829 struct kernel_siginfo info;
3831 prepare_kill_siginfo(sig, &info);
3833 return kill_something_info(sig, &info, pid);
3837 * Verify that the signaler and signalee either are in the same pid namespace
3838 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3841 static bool access_pidfd_pidns(struct pid *pid)
3843 struct pid_namespace *active = task_active_pid_ns(current);
3844 struct pid_namespace *p = ns_of_pid(pid);
3857 static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo,
3858 siginfo_t __user *info)
3860 #ifdef CONFIG_COMPAT
3862 * Avoid hooking up compat syscalls and instead handle necessary
3863 * conversions here. Note, this is a stop-gap measure and should not be
3864 * considered a generic solution.
3866 if (in_compat_syscall())
3867 return copy_siginfo_from_user32(
3868 kinfo, (struct compat_siginfo __user *)info);
3870 return copy_siginfo_from_user(kinfo, info);
3873 static struct pid *pidfd_to_pid(const struct file *file)
3877 pid = pidfd_pid(file);
3881 return tgid_pidfd_to_pid(file);
3885 * sys_pidfd_send_signal - Signal a process through a pidfd
3886 * @pidfd: file descriptor of the process
3887 * @sig: signal to send
3888 * @info: signal info
3889 * @flags: future flags
3891 * The syscall currently only signals via PIDTYPE_PID which covers
3892 * kill(<positive-pid>, <signal>. It does not signal threads or process
3894 * In order to extend the syscall to threads and process groups the @flags
3895 * argument should be used. In essence, the @flags argument will determine
3896 * what is signaled and not the file descriptor itself. Put in other words,
3897 * grouping is a property of the flags argument not a property of the file
3900 * Return: 0 on success, negative errno on failure
3902 SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
3903 siginfo_t __user *, info, unsigned int, flags)
3908 kernel_siginfo_t kinfo;
3910 /* Enforce flags be set to 0 until we add an extension. */
3918 /* Is this a pidfd? */
3919 pid = pidfd_to_pid(f.file);
3926 if (!access_pidfd_pidns(pid))
3930 ret = copy_siginfo_from_user_any(&kinfo, info);
3935 if (unlikely(sig != kinfo.si_signo))
3938 /* Only allow sending arbitrary signals to yourself. */
3940 if ((task_pid(current) != pid) &&
3941 (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
3944 prepare_kill_siginfo(sig, &kinfo);
3947 ret = kill_pid_info(sig, &kinfo, pid);
3955 do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
3957 struct task_struct *p;
3961 p = find_task_by_vpid(pid);
3962 if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
3963 error = check_kill_permission(sig, info, p);
3965 * The null signal is a permissions and process existence
3966 * probe. No signal is actually delivered.
3968 if (!error && sig) {
3969 error = do_send_sig_info(sig, info, p, PIDTYPE_PID);
3971 * If lock_task_sighand() failed we pretend the task
3972 * dies after receiving the signal. The window is tiny,
3973 * and the signal is private anyway.
3975 if (unlikely(error == -ESRCH))
3984 static int do_tkill(pid_t tgid, pid_t pid, int sig)
3986 struct kernel_siginfo info;
3988 clear_siginfo(&info);
3989 info.si_signo = sig;
3991 info.si_code = SI_TKILL;
3992 info.si_pid = task_tgid_vnr(current);
3993 info.si_uid = from_kuid_munged(current_user_ns(), current_uid());
3995 return do_send_specific(tgid, pid, sig, &info);
3999 * sys_tgkill - send signal to one specific thread
4000 * @tgid: the thread group ID of the thread
4001 * @pid: the PID of the thread
4002 * @sig: signal to be sent
4004 * This syscall also checks the @tgid and returns -ESRCH even if the PID
4005 * exists but it's not belonging to the target process anymore. This
4006 * method solves the problem of threads exiting and PIDs getting reused.
4008 SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
4010 /* This is only valid for single tasks */
4011 if (pid <= 0 || tgid <= 0)
4014 return do_tkill(tgid, pid, sig);
4018 * sys_tkill - send signal to one specific task
4019 * @pid: the PID of the task
4020 * @sig: signal to be sent
4022 * Send a signal to only one task, even if it's a CLONE_THREAD task.
4024 SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
4026 /* This is only valid for single tasks */
4030 return do_tkill(0, pid, sig);
4033 static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
4035 /* Not even root can pretend to send signals from the kernel.
4036 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4038 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4039 (task_pid_vnr(current) != pid))
4042 /* POSIX.1b doesn't mention process groups. */
4043 return kill_proc_info(sig, info, pid);
4047 * sys_rt_sigqueueinfo - send signal information to a signal
4048 * @pid: the PID of the thread
4049 * @sig: signal to be sent
4050 * @uinfo: signal info to be sent
4052 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
4053 siginfo_t __user *, uinfo)
4055 kernel_siginfo_t info;
4056 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4059 return do_rt_sigqueueinfo(pid, sig, &info);
4062 #ifdef CONFIG_COMPAT
4063 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
4066 struct compat_siginfo __user *, uinfo)
4068 kernel_siginfo_t info;
4069 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4072 return do_rt_sigqueueinfo(pid, sig, &info);
4076 static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
4078 /* This is only valid for single tasks */
4079 if (pid <= 0 || tgid <= 0)
4082 /* Not even root can pretend to send signals from the kernel.
4083 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4085 if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
4086 (task_pid_vnr(current) != pid))
4089 return do_send_specific(tgid, pid, sig, info);
4092 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
4093 siginfo_t __user *, uinfo)
4095 kernel_siginfo_t info;
4096 int ret = __copy_siginfo_from_user(sig, &info, uinfo);
4099 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4102 #ifdef CONFIG_COMPAT
4103 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
4107 struct compat_siginfo __user *, uinfo)
4109 kernel_siginfo_t info;
4110 int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
4113 return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
4118 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
4120 void kernel_sigaction(int sig, __sighandler_t action)
4122 spin_lock_irq(¤t->sighand->siglock);
4123 current->sighand->action[sig - 1].sa.sa_handler = action;
4124 if (action == SIG_IGN) {
4128 sigaddset(&mask, sig);
4130 flush_sigqueue_mask(&mask, ¤t->signal->shared_pending);
4131 flush_sigqueue_mask(&mask, ¤t->pending);
4132 recalc_sigpending();
4134 spin_unlock_irq(¤t->sighand->siglock);
4136 EXPORT_SYMBOL(kernel_sigaction);
4138 void __weak sigaction_compat_abi(struct k_sigaction *act,
4139 struct k_sigaction *oact)
4143 int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
4145 struct task_struct *p = current, *t;
4146 struct k_sigaction *k;
4149 if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig)))
4152 k = &p->sighand->action[sig-1];
4154 spin_lock_irq(&p->sighand->siglock);
4155 if (k->sa.sa_flags & SA_IMMUTABLE) {
4156 spin_unlock_irq(&p->sighand->siglock);
4163 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
4164 * e.g. by having an architecture use the bit in their uapi.
4166 BUILD_BUG_ON(UAPI_SA_FLAGS & SA_UNSUPPORTED);
4169 * Clear unknown flag bits in order to allow userspace to detect missing
4170 * support for flag bits and to allow the kernel to use non-uapi bits
4174 act->sa.sa_flags &= UAPI_SA_FLAGS;
4176 oact->sa.sa_flags &= UAPI_SA_FLAGS;
4178 sigaction_compat_abi(act, oact);
4181 sigdelsetmask(&act->sa.sa_mask,
4182 sigmask(SIGKILL) | sigmask(SIGSTOP));
4186 * "Setting a signal action to SIG_IGN for a signal that is
4187 * pending shall cause the pending signal to be discarded,
4188 * whether or not it is blocked."
4190 * "Setting a signal action to SIG_DFL for a signal that is
4191 * pending and whose default action is to ignore the signal
4192 * (for example, SIGCHLD), shall cause the pending signal to
4193 * be discarded, whether or not it is blocked"
4195 if (sig_handler_ignored(sig_handler(p, sig), sig)) {
4197 sigaddset(&mask, sig);
4198 flush_sigqueue_mask(&mask, &p->signal->shared_pending);
4199 for_each_thread(p, t)
4200 flush_sigqueue_mask(&mask, &t->pending);
4204 spin_unlock_irq(&p->sighand->siglock);
4208 #ifdef CONFIG_DYNAMIC_SIGFRAME
4209 static inline void sigaltstack_lock(void)
4210 __acquires(¤t->sighand->siglock)
4212 spin_lock_irq(¤t->sighand->siglock);
4215 static inline void sigaltstack_unlock(void)
4216 __releases(¤t->sighand->siglock)
4218 spin_unlock_irq(¤t->sighand->siglock);
4221 static inline void sigaltstack_lock(void) { }
4222 static inline void sigaltstack_unlock(void) { }
4226 do_sigaltstack (const stack_t *ss, stack_t *oss, unsigned long sp,
4229 struct task_struct *t = current;
4233 memset(oss, 0, sizeof(stack_t));
4234 oss->ss_sp = (void __user *) t->sas_ss_sp;
4235 oss->ss_size = t->sas_ss_size;
4236 oss->ss_flags = sas_ss_flags(sp) |
4237 (current->sas_ss_flags & SS_FLAG_BITS);
4241 void __user *ss_sp = ss->ss_sp;
4242 size_t ss_size = ss->ss_size;
4243 unsigned ss_flags = ss->ss_flags;
4246 if (unlikely(on_sig_stack(sp)))
4249 ss_mode = ss_flags & ~SS_FLAG_BITS;
4250 if (unlikely(ss_mode != SS_DISABLE && ss_mode != SS_ONSTACK &&
4255 * Return before taking any locks if no actual
4256 * sigaltstack changes were requested.
4258 if (t->sas_ss_sp == (unsigned long)ss_sp &&
4259 t->sas_ss_size == ss_size &&
4260 t->sas_ss_flags == ss_flags)
4264 if (ss_mode == SS_DISABLE) {
4268 if (unlikely(ss_size < min_ss_size))
4270 if (!sigaltstack_size_valid(ss_size))
4274 t->sas_ss_sp = (unsigned long) ss_sp;
4275 t->sas_ss_size = ss_size;
4276 t->sas_ss_flags = ss_flags;
4278 sigaltstack_unlock();
4283 SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
4287 if (uss && copy_from_user(&new, uss, sizeof(stack_t)))
4289 err = do_sigaltstack(uss ? &new : NULL, uoss ? &old : NULL,
4290 current_user_stack_pointer(),
4292 if (!err && uoss && copy_to_user(uoss, &old, sizeof(stack_t)))
4297 int restore_altstack(const stack_t __user *uss)
4300 if (copy_from_user(&new, uss, sizeof(stack_t)))
4302 (void)do_sigaltstack(&new, NULL, current_user_stack_pointer(),
4304 /* squash all but EFAULT for now */
4308 int __save_altstack(stack_t __user *uss, unsigned long sp)
4310 struct task_struct *t = current;
4311 int err = __put_user((void __user *)t->sas_ss_sp, &uss->ss_sp) |
4312 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4313 __put_user(t->sas_ss_size, &uss->ss_size);
4317 #ifdef CONFIG_COMPAT
4318 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
4319 compat_stack_t __user *uoss_ptr)
4325 compat_stack_t uss32;
4326 if (copy_from_user(&uss32, uss_ptr, sizeof(compat_stack_t)))
4328 uss.ss_sp = compat_ptr(uss32.ss_sp);
4329 uss.ss_flags = uss32.ss_flags;
4330 uss.ss_size = uss32.ss_size;
4332 ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss,
4333 compat_user_stack_pointer(),
4334 COMPAT_MINSIGSTKSZ);
4335 if (ret >= 0 && uoss_ptr) {
4337 memset(&old, 0, sizeof(old));
4338 old.ss_sp = ptr_to_compat(uoss.ss_sp);
4339 old.ss_flags = uoss.ss_flags;
4340 old.ss_size = uoss.ss_size;
4341 if (copy_to_user(uoss_ptr, &old, sizeof(compat_stack_t)))
4347 COMPAT_SYSCALL_DEFINE2(sigaltstack,
4348 const compat_stack_t __user *, uss_ptr,
4349 compat_stack_t __user *, uoss_ptr)
4351 return do_compat_sigaltstack(uss_ptr, uoss_ptr);
4354 int compat_restore_altstack(const compat_stack_t __user *uss)
4356 int err = do_compat_sigaltstack(uss, NULL);
4357 /* squash all but -EFAULT for now */
4358 return err == -EFAULT ? err : 0;
4361 int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
4364 struct task_struct *t = current;
4365 err = __put_user(ptr_to_compat((void __user *)t->sas_ss_sp),
4367 __put_user(t->sas_ss_flags, &uss->ss_flags) |
4368 __put_user(t->sas_ss_size, &uss->ss_size);
4373 #ifdef __ARCH_WANT_SYS_SIGPENDING
4376 * sys_sigpending - examine pending signals
4377 * @uset: where mask of pending signal is returned
4379 SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
4383 if (sizeof(old_sigset_t) > sizeof(*uset))
4386 do_sigpending(&set);
4388 if (copy_to_user(uset, &set, sizeof(old_sigset_t)))
4394 #ifdef CONFIG_COMPAT
4395 COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
4399 do_sigpending(&set);
4401 return put_user(set.sig[0], set32);
4407 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4409 * sys_sigprocmask - examine and change blocked signals
4410 * @how: whether to add, remove, or set signals
4411 * @nset: signals to add or remove (if non-null)
4412 * @oset: previous value of signal mask if non-null
4414 * Some platforms have their own version with special arguments;
4415 * others support only sys_rt_sigprocmask.
4418 SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
4419 old_sigset_t __user *, oset)
4421 old_sigset_t old_set, new_set;
4422 sigset_t new_blocked;
4424 old_set = current->blocked.sig[0];
4427 if (copy_from_user(&new_set, nset, sizeof(*nset)))
4430 new_blocked = current->blocked;
4434 sigaddsetmask(&new_blocked, new_set);
4437 sigdelsetmask(&new_blocked, new_set);
4440 new_blocked.sig[0] = new_set;
4446 set_current_blocked(&new_blocked);
4450 if (copy_to_user(oset, &old_set, sizeof(*oset)))
4456 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4458 #ifndef CONFIG_ODD_RT_SIGACTION
4460 * sys_rt_sigaction - alter an action taken by a process
4461 * @sig: signal to be sent
4462 * @act: new sigaction
4463 * @oact: used to save the previous sigaction
4464 * @sigsetsize: size of sigset_t type
4466 SYSCALL_DEFINE4(rt_sigaction, int, sig,
4467 const struct sigaction __user *, act,
4468 struct sigaction __user *, oact,
4471 struct k_sigaction new_sa, old_sa;
4474 /* XXX: Don't preclude handling different sized sigset_t's. */
4475 if (sigsetsize != sizeof(sigset_t))
4478 if (act && copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa)))
4481 ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);
4485 if (oact && copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa)))
4490 #ifdef CONFIG_COMPAT
4491 COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
4492 const struct compat_sigaction __user *, act,
4493 struct compat_sigaction __user *, oact,
4494 compat_size_t, sigsetsize)
4496 struct k_sigaction new_ka, old_ka;
4497 #ifdef __ARCH_HAS_SA_RESTORER
4498 compat_uptr_t restorer;
4502 /* XXX: Don't preclude handling different sized sigset_t's. */
4503 if (sigsetsize != sizeof(compat_sigset_t))
4507 compat_uptr_t handler;
4508 ret = get_user(handler, &act->sa_handler);
4509 new_ka.sa.sa_handler = compat_ptr(handler);
4510 #ifdef __ARCH_HAS_SA_RESTORER
4511 ret |= get_user(restorer, &act->sa_restorer);
4512 new_ka.sa.sa_restorer = compat_ptr(restorer);
4514 ret |= get_compat_sigset(&new_ka.sa.sa_mask, &act->sa_mask);
4515 ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
4520 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4522 ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
4524 ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
4525 sizeof(oact->sa_mask));
4526 ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
4527 #ifdef __ARCH_HAS_SA_RESTORER
4528 ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4529 &oact->sa_restorer);
4535 #endif /* !CONFIG_ODD_RT_SIGACTION */
4537 #ifdef CONFIG_OLD_SIGACTION
4538 SYSCALL_DEFINE3(sigaction, int, sig,
4539 const struct old_sigaction __user *, act,
4540 struct old_sigaction __user *, oact)
4542 struct k_sigaction new_ka, old_ka;
4547 if (!access_ok(act, sizeof(*act)) ||
4548 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
4549 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
4550 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4551 __get_user(mask, &act->sa_mask))
4553 #ifdef __ARCH_HAS_KA_RESTORER
4554 new_ka.ka_restorer = NULL;
4556 siginitset(&new_ka.sa.sa_mask, mask);
4559 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4562 if (!access_ok(oact, sizeof(*oact)) ||
4563 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
4564 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
4565 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4566 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4573 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4574 COMPAT_SYSCALL_DEFINE3(sigaction, int, sig,
4575 const struct compat_old_sigaction __user *, act,
4576 struct compat_old_sigaction __user *, oact)
4578 struct k_sigaction new_ka, old_ka;
4580 compat_old_sigset_t mask;
4581 compat_uptr_t handler, restorer;
4584 if (!access_ok(act, sizeof(*act)) ||
4585 __get_user(handler, &act->sa_handler) ||
4586 __get_user(restorer, &act->sa_restorer) ||
4587 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
4588 __get_user(mask, &act->sa_mask))
4591 #ifdef __ARCH_HAS_KA_RESTORER
4592 new_ka.ka_restorer = NULL;
4594 new_ka.sa.sa_handler = compat_ptr(handler);
4595 new_ka.sa.sa_restorer = compat_ptr(restorer);
4596 siginitset(&new_ka.sa.sa_mask, mask);
4599 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
4602 if (!access_ok(oact, sizeof(*oact)) ||
4603 __put_user(ptr_to_compat(old_ka.sa.sa_handler),
4604 &oact->sa_handler) ||
4605 __put_user(ptr_to_compat(old_ka.sa.sa_restorer),
4606 &oact->sa_restorer) ||
4607 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
4608 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
4615 #ifdef CONFIG_SGETMASK_SYSCALL
4618 * For backwards compatibility. Functionality superseded by sigprocmask.
4620 SYSCALL_DEFINE0(sgetmask)
4623 return current->blocked.sig[0];
4626 SYSCALL_DEFINE1(ssetmask, int, newmask)
4628 int old = current->blocked.sig[0];
4631 siginitset(&newset, newmask);
4632 set_current_blocked(&newset);
4636 #endif /* CONFIG_SGETMASK_SYSCALL */
4638 #ifdef __ARCH_WANT_SYS_SIGNAL
4640 * For backwards compatibility. Functionality superseded by sigaction.
4642 SYSCALL_DEFINE2(signal, int, sig, __sighandler_t, handler)
4644 struct k_sigaction new_sa, old_sa;
4647 new_sa.sa.sa_handler = handler;
4648 new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK;
4649 sigemptyset(&new_sa.sa.sa_mask);
4651 ret = do_sigaction(sig, &new_sa, &old_sa);
4653 return ret ? ret : (unsigned long)old_sa.sa.sa_handler;
4655 #endif /* __ARCH_WANT_SYS_SIGNAL */
4657 #ifdef __ARCH_WANT_SYS_PAUSE
4659 SYSCALL_DEFINE0(pause)
4661 while (!signal_pending(current)) {
4662 __set_current_state(TASK_INTERRUPTIBLE);
4665 return -ERESTARTNOHAND;
4670 static int sigsuspend(sigset_t *set)
4672 current->saved_sigmask = current->blocked;
4673 set_current_blocked(set);
4675 while (!signal_pending(current)) {
4676 __set_current_state(TASK_INTERRUPTIBLE);
4679 set_restore_sigmask();
4680 return -ERESTARTNOHAND;
4684 * sys_rt_sigsuspend - replace the signal mask for a value with the
4685 * @unewset value until a signal is received
4686 * @unewset: new signal mask value
4687 * @sigsetsize: size of sigset_t type
4689 SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
4693 /* XXX: Don't preclude handling different sized sigset_t's. */
4694 if (sigsetsize != sizeof(sigset_t))
4697 if (copy_from_user(&newset, unewset, sizeof(newset)))
4699 return sigsuspend(&newset);
4702 #ifdef CONFIG_COMPAT
4703 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend, compat_sigset_t __user *, unewset, compat_size_t, sigsetsize)
4707 /* XXX: Don't preclude handling different sized sigset_t's. */
4708 if (sigsetsize != sizeof(sigset_t))
4711 if (get_compat_sigset(&newset, unewset))
4713 return sigsuspend(&newset);
4717 #ifdef CONFIG_OLD_SIGSUSPEND
4718 SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
4721 siginitset(&blocked, mask);
4722 return sigsuspend(&blocked);
4725 #ifdef CONFIG_OLD_SIGSUSPEND3
4726 SYSCALL_DEFINE3(sigsuspend, int, unused1, int, unused2, old_sigset_t, mask)
4729 siginitset(&blocked, mask);
4730 return sigsuspend(&blocked);
4734 __weak const char *arch_vma_name(struct vm_area_struct *vma)
4739 static inline void siginfo_buildtime_checks(void)
4741 BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
4743 /* Verify the offsets in the two siginfos match */
4744 #define CHECK_OFFSET(field) \
4745 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4748 CHECK_OFFSET(si_pid);
4749 CHECK_OFFSET(si_uid);
4752 CHECK_OFFSET(si_tid);
4753 CHECK_OFFSET(si_overrun);
4754 CHECK_OFFSET(si_value);
4757 CHECK_OFFSET(si_pid);
4758 CHECK_OFFSET(si_uid);
4759 CHECK_OFFSET(si_value);
4762 CHECK_OFFSET(si_pid);
4763 CHECK_OFFSET(si_uid);
4764 CHECK_OFFSET(si_status);
4765 CHECK_OFFSET(si_utime);
4766 CHECK_OFFSET(si_stime);
4769 CHECK_OFFSET(si_addr);
4770 CHECK_OFFSET(si_trapno);
4771 CHECK_OFFSET(si_addr_lsb);
4772 CHECK_OFFSET(si_lower);
4773 CHECK_OFFSET(si_upper);
4774 CHECK_OFFSET(si_pkey);
4775 CHECK_OFFSET(si_perf_data);
4776 CHECK_OFFSET(si_perf_type);
4777 CHECK_OFFSET(si_perf_flags);
4780 CHECK_OFFSET(si_band);
4781 CHECK_OFFSET(si_fd);
4784 CHECK_OFFSET(si_call_addr);
4785 CHECK_OFFSET(si_syscall);
4786 CHECK_OFFSET(si_arch);
4790 BUILD_BUG_ON(offsetof(struct siginfo, si_pid) !=
4791 offsetof(struct siginfo, si_addr));
4792 if (sizeof(int) == sizeof(void __user *)) {
4793 BUILD_BUG_ON(sizeof_field(struct siginfo, si_pid) !=
4794 sizeof(void __user *));
4796 BUILD_BUG_ON((sizeof_field(struct siginfo, si_pid) +
4797 sizeof_field(struct siginfo, si_uid)) !=
4798 sizeof(void __user *));
4799 BUILD_BUG_ON(offsetofend(struct siginfo, si_pid) !=
4800 offsetof(struct siginfo, si_uid));
4802 #ifdef CONFIG_COMPAT
4803 BUILD_BUG_ON(offsetof(struct compat_siginfo, si_pid) !=
4804 offsetof(struct compat_siginfo, si_addr));
4805 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4806 sizeof(compat_uptr_t));
4807 BUILD_BUG_ON(sizeof_field(struct compat_siginfo, si_pid) !=
4808 sizeof_field(struct siginfo, si_pid));
4812 #if defined(CONFIG_SYSCTL)
4813 static struct ctl_table signal_debug_table[] = {
4814 #ifdef CONFIG_SYSCTL_EXCEPTION_TRACE
4816 .procname = "exception-trace",
4817 .data = &show_unhandled_signals,
4818 .maxlen = sizeof(int),
4820 .proc_handler = proc_dointvec
4826 static int __init init_signal_sysctls(void)
4828 register_sysctl_init("debug", signal_debug_table);
4831 early_initcall(init_signal_sysctls);
4832 #endif /* CONFIG_SYSCTL */
4834 void __init signals_init(void)
4836 siginfo_buildtime_checks();
4838 sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC | SLAB_ACCOUNT);
4841 #ifdef CONFIG_KGDB_KDB
4842 #include <linux/kdb.h>
4844 * kdb_send_sig - Allows kdb to send signals without exposing
4845 * signal internals. This function checks if the required locks are
4846 * available before calling the main signal code, to avoid kdb
4849 void kdb_send_sig(struct task_struct *t, int sig)
4851 static struct task_struct *kdb_prev_t;
4853 if (!spin_trylock(&t->sighand->siglock)) {
4854 kdb_printf("Can't do kill command now.\n"
4855 "The sigmask lock is held somewhere else in "
4856 "kernel, try again later\n");
4859 new_t = kdb_prev_t != t;
4861 if (!task_is_running(t) && new_t) {
4862 spin_unlock(&t->sighand->siglock);
4863 kdb_printf("Process is not RUNNING, sending a signal from "
4864 "kdb risks deadlock\n"
4865 "on the run queue locks. "
4866 "The signal has _not_ been sent.\n"
4867 "Reissue the kill command if you want to risk "
4871 ret = send_signal_locked(sig, SEND_SIG_PRIV, t, PIDTYPE_PID);
4872 spin_unlock(&t->sighand->siglock);
4874 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4877 kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
4879 #endif /* CONFIG_KGDB_KDB */