1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/signal.c
5 * Copyright (C) 1991, 1992 Linus Torvalds
7 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
9 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
10 * Changes to use preallocated sigqueue structures
11 * to allow signals to be sent reliably.
14 #include <linux/slab.h>
15 #include <linux/export.h>
16 #include <linux/init.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/user.h>
19 #include <linux/sched/debug.h>
20 #include <linux/sched/task.h>
21 #include <linux/sched/task_stack.h>
22 #include <linux/sched/cputime.h>
23 #include <linux/file.h>
25 #include <linux/proc_fs.h>
26 #include <linux/tty.h>
27 #include <linux/binfmts.h>
28 #include <linux/coredump.h>
29 #include <linux/security.h>
30 #include <linux/syscalls.h>
31 #include <linux/ptrace.h>
32 #include <linux/signal.h>
33 #include <linux/signalfd.h>
34 #include <linux/ratelimit.h>
35 #include <linux/tracehook.h>
36 #include <linux/capability.h>
37 #include <linux/freezer.h>
38 #include <linux/pid_namespace.h>
39 #include <linux/nsproxy.h>
40 #include <linux/user_namespace.h>
41 #include <linux/uprobes.h>
42 #include <linux/compat.h>
43 #include <linux/cn_proc.h>
44 #include <linux/compiler.h>
45 #include <linux/posix-timers.h>
46 #include <linux/cgroup.h>
47 #include <linux/audit.h>
49 #define CREATE_TRACE_POINTS
50 #include <trace/events/signal.h>
52 #include <asm/param.h>
53 #include <linux/uaccess.h>
54 #include <asm/unistd.h>
55 #include <asm/siginfo.h>
56 #include <asm/cacheflush.h>
57 #include <asm/syscall.h> /* for syscall_get_* */
60 * SLAB caches for signal bits.
63 static struct kmem_cache
*sigqueue_cachep
;
65 int print_fatal_signals __read_mostly
;
67 static void __user
*sig_handler(struct task_struct
*t
, int sig
)
69 return t
->sighand
->action
[sig
- 1].sa
.sa_handler
;
72 static inline bool sig_handler_ignored(void __user
*handler
, int sig
)
74 /* Is it explicitly or implicitly ignored? */
75 return handler
== SIG_IGN
||
76 (handler
== SIG_DFL
&& sig_kernel_ignore(sig
));
79 static bool sig_task_ignored(struct task_struct
*t
, int sig
, bool force
)
83 handler
= sig_handler(t
, sig
);
85 /* SIGKILL and SIGSTOP may not be sent to the global init */
86 if (unlikely(is_global_init(t
) && sig_kernel_only(sig
)))
89 if (unlikely(t
->signal
->flags
& SIGNAL_UNKILLABLE
) &&
90 handler
== SIG_DFL
&& !(force
&& sig_kernel_only(sig
)))
93 /* Only allow kernel generated signals to this kthread */
94 if (unlikely((t
->flags
& PF_KTHREAD
) &&
95 (handler
== SIG_KTHREAD_KERNEL
) && !force
))
98 return sig_handler_ignored(handler
, sig
);
101 static bool sig_ignored(struct task_struct
*t
, int sig
, bool force
)
104 * Blocked signals are never ignored, since the
105 * signal handler may change by the time it is
108 if (sigismember(&t
->blocked
, sig
) || sigismember(&t
->real_blocked
, sig
))
112 * Tracers may want to know about even ignored signal unless it
113 * is SIGKILL which can't be reported anyway but can be ignored
114 * by SIGNAL_UNKILLABLE task.
116 if (t
->ptrace
&& sig
!= SIGKILL
)
119 return sig_task_ignored(t
, sig
, force
);
123 * Re-calculate pending state from the set of locally pending
124 * signals, globally pending signals, and blocked signals.
126 static inline bool has_pending_signals(sigset_t
*signal
, sigset_t
*blocked
)
131 switch (_NSIG_WORDS
) {
133 for (i
= _NSIG_WORDS
, ready
= 0; --i
>= 0 ;)
134 ready
|= signal
->sig
[i
] &~ blocked
->sig
[i
];
137 case 4: ready
= signal
->sig
[3] &~ blocked
->sig
[3];
138 ready
|= signal
->sig
[2] &~ blocked
->sig
[2];
139 ready
|= signal
->sig
[1] &~ blocked
->sig
[1];
140 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
143 case 2: ready
= signal
->sig
[1] &~ blocked
->sig
[1];
144 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
147 case 1: ready
= signal
->sig
[0] &~ blocked
->sig
[0];
152 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
154 static bool recalc_sigpending_tsk(struct task_struct
*t
)
156 if ((t
->jobctl
& (JOBCTL_PENDING_MASK
| JOBCTL_TRAP_FREEZE
)) ||
157 PENDING(&t
->pending
, &t
->blocked
) ||
158 PENDING(&t
->signal
->shared_pending
, &t
->blocked
) ||
159 cgroup_task_frozen(t
)) {
160 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
165 * We must never clear the flag in another thread, or in current
166 * when it's possible the current syscall is returning -ERESTART*.
167 * So we don't clear it here, and only callers who know they should do.
173 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
174 * This is superfluous when called on current, the wakeup is a harmless no-op.
176 void recalc_sigpending_and_wake(struct task_struct
*t
)
178 if (recalc_sigpending_tsk(t
))
179 signal_wake_up(t
, 0);
182 void recalc_sigpending(void)
184 if (!recalc_sigpending_tsk(current
) && !freezing(current
))
185 clear_thread_flag(TIF_SIGPENDING
);
188 EXPORT_SYMBOL(recalc_sigpending
);
190 void calculate_sigpending(void)
192 /* Have any signals or users of TIF_SIGPENDING been delayed
195 spin_lock_irq(¤t
->sighand
->siglock
);
196 set_tsk_thread_flag(current
, TIF_SIGPENDING
);
198 spin_unlock_irq(¤t
->sighand
->siglock
);
201 /* Given the mask, find the first available signal that should be serviced. */
203 #define SYNCHRONOUS_MASK \
204 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
205 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
207 int next_signal(struct sigpending
*pending
, sigset_t
*mask
)
209 unsigned long i
, *s
, *m
, x
;
212 s
= pending
->signal
.sig
;
216 * Handle the first word specially: it contains the
217 * synchronous signals that need to be dequeued first.
221 if (x
& SYNCHRONOUS_MASK
)
222 x
&= SYNCHRONOUS_MASK
;
227 switch (_NSIG_WORDS
) {
229 for (i
= 1; i
< _NSIG_WORDS
; ++i
) {
233 sig
= ffz(~x
) + i
*_NSIG_BPW
+ 1;
242 sig
= ffz(~x
) + _NSIG_BPW
+ 1;
253 static inline void print_dropped_signal(int sig
)
255 static DEFINE_RATELIMIT_STATE(ratelimit_state
, 5 * HZ
, 10);
257 if (!print_fatal_signals
)
260 if (!__ratelimit(&ratelimit_state
))
263 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
264 current
->comm
, current
->pid
, sig
);
268 * task_set_jobctl_pending - set jobctl pending bits
270 * @mask: pending bits to set
272 * Clear @mask from @task->jobctl. @mask must be subset of
273 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
274 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
275 * cleared. If @task is already being killed or exiting, this function
279 * Must be called with @task->sighand->siglock held.
282 * %true if @mask is set, %false if made noop because @task was dying.
284 bool task_set_jobctl_pending(struct task_struct
*task
, unsigned long mask
)
286 BUG_ON(mask
& ~(JOBCTL_PENDING_MASK
| JOBCTL_STOP_CONSUME
|
287 JOBCTL_STOP_SIGMASK
| JOBCTL_TRAPPING
));
288 BUG_ON((mask
& JOBCTL_TRAPPING
) && !(mask
& JOBCTL_PENDING_MASK
));
290 if (unlikely(fatal_signal_pending(task
) || (task
->flags
& PF_EXITING
)))
293 if (mask
& JOBCTL_STOP_SIGMASK
)
294 task
->jobctl
&= ~JOBCTL_STOP_SIGMASK
;
296 task
->jobctl
|= mask
;
301 * task_clear_jobctl_trapping - clear jobctl trapping bit
304 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
305 * Clear it and wake up the ptracer. Note that we don't need any further
306 * locking. @task->siglock guarantees that @task->parent points to the
310 * Must be called with @task->sighand->siglock held.
312 void task_clear_jobctl_trapping(struct task_struct
*task
)
314 if (unlikely(task
->jobctl
& JOBCTL_TRAPPING
)) {
315 task
->jobctl
&= ~JOBCTL_TRAPPING
;
316 smp_mb(); /* advised by wake_up_bit() */
317 wake_up_bit(&task
->jobctl
, JOBCTL_TRAPPING_BIT
);
322 * task_clear_jobctl_pending - clear jobctl pending bits
324 * @mask: pending bits to clear
326 * Clear @mask from @task->jobctl. @mask must be subset of
327 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
328 * STOP bits are cleared together.
330 * If clearing of @mask leaves no stop or trap pending, this function calls
331 * task_clear_jobctl_trapping().
334 * Must be called with @task->sighand->siglock held.
336 void task_clear_jobctl_pending(struct task_struct
*task
, unsigned long mask
)
338 BUG_ON(mask
& ~JOBCTL_PENDING_MASK
);
340 if (mask
& JOBCTL_STOP_PENDING
)
341 mask
|= JOBCTL_STOP_CONSUME
| JOBCTL_STOP_DEQUEUED
;
343 task
->jobctl
&= ~mask
;
345 if (!(task
->jobctl
& JOBCTL_PENDING_MASK
))
346 task_clear_jobctl_trapping(task
);
350 * task_participate_group_stop - participate in a group stop
351 * @task: task participating in a group stop
353 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
354 * Group stop states are cleared and the group stop count is consumed if
355 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
356 * stop, the appropriate `SIGNAL_*` flags are set.
359 * Must be called with @task->sighand->siglock held.
362 * %true if group stop completion should be notified to the parent, %false
365 static bool task_participate_group_stop(struct task_struct
*task
)
367 struct signal_struct
*sig
= task
->signal
;
368 bool consume
= task
->jobctl
& JOBCTL_STOP_CONSUME
;
370 WARN_ON_ONCE(!(task
->jobctl
& JOBCTL_STOP_PENDING
));
372 task_clear_jobctl_pending(task
, JOBCTL_STOP_PENDING
);
377 if (!WARN_ON_ONCE(sig
->group_stop_count
== 0))
378 sig
->group_stop_count
--;
381 * Tell the caller to notify completion iff we are entering into a
382 * fresh group stop. Read comment in do_signal_stop() for details.
384 if (!sig
->group_stop_count
&& !(sig
->flags
& SIGNAL_STOP_STOPPED
)) {
385 signal_set_stop_flags(sig
, SIGNAL_STOP_STOPPED
);
391 void task_join_group_stop(struct task_struct
*task
)
393 unsigned long mask
= current
->jobctl
& JOBCTL_STOP_SIGMASK
;
394 struct signal_struct
*sig
= current
->signal
;
396 if (sig
->group_stop_count
) {
397 sig
->group_stop_count
++;
398 mask
|= JOBCTL_STOP_CONSUME
;
399 } else if (!(sig
->flags
& SIGNAL_STOP_STOPPED
))
402 /* Have the new thread join an on-going signal group stop */
403 task_set_jobctl_pending(task
, mask
| JOBCTL_STOP_PENDING
);
407 * allocate a new signal queue record
408 * - this may be called without locks if and only if t == current, otherwise an
409 * appropriate lock must be held to stop the target task from exiting
411 static struct sigqueue
*
412 __sigqueue_alloc(int sig
, struct task_struct
*t
, gfp_t gfp_flags
,
413 int override_rlimit
, const unsigned int sigqueue_flags
)
415 struct sigqueue
*q
= NULL
;
416 struct ucounts
*ucounts
= NULL
;
420 * Protect access to @t credentials. This can go away when all
421 * callers hold rcu read lock.
423 * NOTE! A pending signal will hold on to the user refcount,
424 * and we get/put the refcount only when the sigpending count
425 * changes from/to zero.
428 ucounts
= task_ucounts(t
);
429 sigpending
= inc_rlimit_get_ucounts(ucounts
, UCOUNT_RLIMIT_SIGPENDING
);
434 if (override_rlimit
|| likely(sigpending
<= task_rlimit(t
, RLIMIT_SIGPENDING
))) {
435 q
= kmem_cache_alloc(sigqueue_cachep
, gfp_flags
);
437 print_dropped_signal(sig
);
440 if (unlikely(q
== NULL
)) {
441 dec_rlimit_put_ucounts(ucounts
, UCOUNT_RLIMIT_SIGPENDING
);
443 INIT_LIST_HEAD(&q
->list
);
444 q
->flags
= sigqueue_flags
;
445 q
->ucounts
= ucounts
;
450 static void __sigqueue_free(struct sigqueue
*q
)
452 if (q
->flags
& SIGQUEUE_PREALLOC
)
455 dec_rlimit_put_ucounts(q
->ucounts
, UCOUNT_RLIMIT_SIGPENDING
);
458 kmem_cache_free(sigqueue_cachep
, q
);
461 void flush_sigqueue(struct sigpending
*queue
)
465 sigemptyset(&queue
->signal
);
466 while (!list_empty(&queue
->list
)) {
467 q
= list_entry(queue
->list
.next
, struct sigqueue
, list
);
468 list_del_init(&q
->list
);
474 * Flush all pending signals for this kthread.
476 void flush_signals(struct task_struct
*t
)
480 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
481 clear_tsk_thread_flag(t
, TIF_SIGPENDING
);
482 flush_sigqueue(&t
->pending
);
483 flush_sigqueue(&t
->signal
->shared_pending
);
484 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
486 EXPORT_SYMBOL(flush_signals
);
488 #ifdef CONFIG_POSIX_TIMERS
489 static void __flush_itimer_signals(struct sigpending
*pending
)
491 sigset_t signal
, retain
;
492 struct sigqueue
*q
, *n
;
494 signal
= pending
->signal
;
495 sigemptyset(&retain
);
497 list_for_each_entry_safe(q
, n
, &pending
->list
, list
) {
498 int sig
= q
->info
.si_signo
;
500 if (likely(q
->info
.si_code
!= SI_TIMER
)) {
501 sigaddset(&retain
, sig
);
503 sigdelset(&signal
, sig
);
504 list_del_init(&q
->list
);
509 sigorsets(&pending
->signal
, &signal
, &retain
);
512 void flush_itimer_signals(void)
514 struct task_struct
*tsk
= current
;
517 spin_lock_irqsave(&tsk
->sighand
->siglock
, flags
);
518 __flush_itimer_signals(&tsk
->pending
);
519 __flush_itimer_signals(&tsk
->signal
->shared_pending
);
520 spin_unlock_irqrestore(&tsk
->sighand
->siglock
, flags
);
524 void ignore_signals(struct task_struct
*t
)
528 for (i
= 0; i
< _NSIG
; ++i
)
529 t
->sighand
->action
[i
].sa
.sa_handler
= SIG_IGN
;
535 * Flush all handlers for a task.
539 flush_signal_handlers(struct task_struct
*t
, int force_default
)
542 struct k_sigaction
*ka
= &t
->sighand
->action
[0];
543 for (i
= _NSIG
; i
!= 0 ; i
--) {
544 if (force_default
|| ka
->sa
.sa_handler
!= SIG_IGN
)
545 ka
->sa
.sa_handler
= SIG_DFL
;
547 #ifdef __ARCH_HAS_SA_RESTORER
548 ka
->sa
.sa_restorer
= NULL
;
550 sigemptyset(&ka
->sa
.sa_mask
);
555 bool unhandled_signal(struct task_struct
*tsk
, int sig
)
557 void __user
*handler
= tsk
->sighand
->action
[sig
-1].sa
.sa_handler
;
558 if (is_global_init(tsk
))
561 if (handler
!= SIG_IGN
&& handler
!= SIG_DFL
)
564 /* if ptraced, let the tracer determine */
568 static void collect_signal(int sig
, struct sigpending
*list
, kernel_siginfo_t
*info
,
571 struct sigqueue
*q
, *first
= NULL
;
574 * Collect the siginfo appropriate to this signal. Check if
575 * there is another siginfo for the same signal.
577 list_for_each_entry(q
, &list
->list
, list
) {
578 if (q
->info
.si_signo
== sig
) {
585 sigdelset(&list
->signal
, sig
);
589 list_del_init(&first
->list
);
590 copy_siginfo(info
, &first
->info
);
593 (first
->flags
& SIGQUEUE_PREALLOC
) &&
594 (info
->si_code
== SI_TIMER
) &&
595 (info
->si_sys_private
);
597 __sigqueue_free(first
);
600 * Ok, it wasn't in the queue. This must be
601 * a fast-pathed signal or we must have been
602 * out of queue space. So zero out the info.
605 info
->si_signo
= sig
;
607 info
->si_code
= SI_USER
;
613 static int __dequeue_signal(struct sigpending
*pending
, sigset_t
*mask
,
614 kernel_siginfo_t
*info
, bool *resched_timer
)
616 int sig
= next_signal(pending
, mask
);
619 collect_signal(sig
, pending
, info
, resched_timer
);
624 * Dequeue a signal and return the element to the caller, which is
625 * expected to free it.
627 * All callers have to hold the siglock.
629 int dequeue_signal(struct task_struct
*tsk
, sigset_t
*mask
, kernel_siginfo_t
*info
)
631 bool resched_timer
= false;
634 /* We only dequeue private signals from ourselves, we don't let
635 * signalfd steal them
637 signr
= __dequeue_signal(&tsk
->pending
, mask
, info
, &resched_timer
);
639 signr
= __dequeue_signal(&tsk
->signal
->shared_pending
,
640 mask
, info
, &resched_timer
);
641 #ifdef CONFIG_POSIX_TIMERS
645 * itimers are process shared and we restart periodic
646 * itimers in the signal delivery path to prevent DoS
647 * attacks in the high resolution timer case. This is
648 * compliant with the old way of self-restarting
649 * itimers, as the SIGALRM is a legacy signal and only
650 * queued once. Changing the restart behaviour to
651 * restart the timer in the signal dequeue path is
652 * reducing the timer noise on heavy loaded !highres
655 if (unlikely(signr
== SIGALRM
)) {
656 struct hrtimer
*tmr
= &tsk
->signal
->real_timer
;
658 if (!hrtimer_is_queued(tmr
) &&
659 tsk
->signal
->it_real_incr
!= 0) {
660 hrtimer_forward(tmr
, tmr
->base
->get_time(),
661 tsk
->signal
->it_real_incr
);
662 hrtimer_restart(tmr
);
672 if (unlikely(sig_kernel_stop(signr
))) {
674 * Set a marker that we have dequeued a stop signal. Our
675 * caller might release the siglock and then the pending
676 * stop signal it is about to process is no longer in the
677 * pending bitmasks, but must still be cleared by a SIGCONT
678 * (and overruled by a SIGKILL). So those cases clear this
679 * shared flag after we've set it. Note that this flag may
680 * remain set after the signal we return is ignored or
681 * handled. That doesn't matter because its only purpose
682 * is to alert stop-signal processing code when another
683 * processor has come along and cleared the flag.
685 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
687 #ifdef CONFIG_POSIX_TIMERS
690 * Release the siglock to ensure proper locking order
691 * of timer locks outside of siglocks. Note, we leave
692 * irqs disabled here, since the posix-timers code is
693 * about to disable them again anyway.
695 spin_unlock(&tsk
->sighand
->siglock
);
696 posixtimer_rearm(info
);
697 spin_lock(&tsk
->sighand
->siglock
);
699 /* Don't expose the si_sys_private value to userspace */
700 info
->si_sys_private
= 0;
705 EXPORT_SYMBOL_GPL(dequeue_signal
);
707 static int dequeue_synchronous_signal(kernel_siginfo_t
*info
)
709 struct task_struct
*tsk
= current
;
710 struct sigpending
*pending
= &tsk
->pending
;
711 struct sigqueue
*q
, *sync
= NULL
;
714 * Might a synchronous signal be in the queue?
716 if (!((pending
->signal
.sig
[0] & ~tsk
->blocked
.sig
[0]) & SYNCHRONOUS_MASK
))
720 * Return the first synchronous signal in the queue.
722 list_for_each_entry(q
, &pending
->list
, list
) {
723 /* Synchronous signals have a positive si_code */
724 if ((q
->info
.si_code
> SI_USER
) &&
725 (sigmask(q
->info
.si_signo
) & SYNCHRONOUS_MASK
)) {
733 * Check if there is another siginfo for the same signal.
735 list_for_each_entry_continue(q
, &pending
->list
, list
) {
736 if (q
->info
.si_signo
== sync
->info
.si_signo
)
740 sigdelset(&pending
->signal
, sync
->info
.si_signo
);
743 list_del_init(&sync
->list
);
744 copy_siginfo(info
, &sync
->info
);
745 __sigqueue_free(sync
);
746 return info
->si_signo
;
750 * Tell a process that it has a new active signal..
752 * NOTE! we rely on the previous spin_lock to
753 * lock interrupts for us! We can only be called with
754 * "siglock" held, and the local interrupt must
755 * have been disabled when that got acquired!
757 * No need to set need_resched since signal event passing
758 * goes through ->blocked
760 void signal_wake_up_state(struct task_struct
*t
, unsigned int state
)
762 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
764 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
765 * case. We don't check t->state here because there is a race with it
766 * executing another processor and just now entering stopped state.
767 * By using wake_up_state, we ensure the process will wake up and
768 * handle its death signal.
770 if (!wake_up_state(t
, state
| TASK_INTERRUPTIBLE
))
775 * Remove signals in mask from the pending set and queue.
776 * Returns 1 if any signals were found.
778 * All callers must be holding the siglock.
780 static void flush_sigqueue_mask(sigset_t
*mask
, struct sigpending
*s
)
782 struct sigqueue
*q
, *n
;
785 sigandsets(&m
, mask
, &s
->signal
);
786 if (sigisemptyset(&m
))
789 sigandnsets(&s
->signal
, &s
->signal
, mask
);
790 list_for_each_entry_safe(q
, n
, &s
->list
, list
) {
791 if (sigismember(mask
, q
->info
.si_signo
)) {
792 list_del_init(&q
->list
);
798 static inline int is_si_special(const struct kernel_siginfo
*info
)
800 return info
<= SEND_SIG_PRIV
;
803 static inline bool si_fromuser(const struct kernel_siginfo
*info
)
805 return info
== SEND_SIG_NOINFO
||
806 (!is_si_special(info
) && SI_FROMUSER(info
));
810 * called with RCU read lock from check_kill_permission()
812 static bool kill_ok_by_cred(struct task_struct
*t
)
814 const struct cred
*cred
= current_cred();
815 const struct cred
*tcred
= __task_cred(t
);
817 return uid_eq(cred
->euid
, tcred
->suid
) ||
818 uid_eq(cred
->euid
, tcred
->uid
) ||
819 uid_eq(cred
->uid
, tcred
->suid
) ||
820 uid_eq(cred
->uid
, tcred
->uid
) ||
821 ns_capable(tcred
->user_ns
, CAP_KILL
);
825 * Bad permissions for sending the signal
826 * - the caller must hold the RCU read lock
828 static int check_kill_permission(int sig
, struct kernel_siginfo
*info
,
829 struct task_struct
*t
)
834 if (!valid_signal(sig
))
837 if (!si_fromuser(info
))
840 error
= audit_signal_info(sig
, t
); /* Let audit system see the signal */
844 if (!same_thread_group(current
, t
) &&
845 !kill_ok_by_cred(t
)) {
848 sid
= task_session(t
);
850 * We don't return the error if sid == NULL. The
851 * task was unhashed, the caller must notice this.
853 if (!sid
|| sid
== task_session(current
))
861 return security_task_kill(t
, info
, sig
, NULL
);
865 * ptrace_trap_notify - schedule trap to notify ptracer
866 * @t: tracee wanting to notify tracer
868 * This function schedules sticky ptrace trap which is cleared on the next
869 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
872 * If @t is running, STOP trap will be taken. If trapped for STOP and
873 * ptracer is listening for events, tracee is woken up so that it can
874 * re-trap for the new event. If trapped otherwise, STOP trap will be
875 * eventually taken without returning to userland after the existing traps
876 * are finished by PTRACE_CONT.
879 * Must be called with @task->sighand->siglock held.
881 static void ptrace_trap_notify(struct task_struct
*t
)
883 WARN_ON_ONCE(!(t
->ptrace
& PT_SEIZED
));
884 assert_spin_locked(&t
->sighand
->siglock
);
886 task_set_jobctl_pending(t
, JOBCTL_TRAP_NOTIFY
);
887 ptrace_signal_wake_up(t
, t
->jobctl
& JOBCTL_LISTENING
);
891 * Handle magic process-wide effects of stop/continue signals. Unlike
892 * the signal actions, these happen immediately at signal-generation
893 * time regardless of blocking, ignoring, or handling. This does the
894 * actual continuing for SIGCONT, but not the actual stopping for stop
895 * signals. The process stop is done as a signal action for SIG_DFL.
897 * Returns true if the signal should be actually delivered, otherwise
898 * it should be dropped.
900 static bool prepare_signal(int sig
, struct task_struct
*p
, bool force
)
902 struct signal_struct
*signal
= p
->signal
;
903 struct task_struct
*t
;
906 if (signal
->flags
& (SIGNAL_GROUP_EXIT
| SIGNAL_GROUP_COREDUMP
)) {
907 if (!(signal
->flags
& SIGNAL_GROUP_EXIT
))
908 return sig
== SIGKILL
;
910 * The process is in the middle of dying, nothing to do.
912 } else if (sig_kernel_stop(sig
)) {
914 * This is a stop signal. Remove SIGCONT from all queues.
916 siginitset(&flush
, sigmask(SIGCONT
));
917 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
918 for_each_thread(p
, t
)
919 flush_sigqueue_mask(&flush
, &t
->pending
);
920 } else if (sig
== SIGCONT
) {
923 * Remove all stop signals from all queues, wake all threads.
925 siginitset(&flush
, SIG_KERNEL_STOP_MASK
);
926 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
927 for_each_thread(p
, t
) {
928 flush_sigqueue_mask(&flush
, &t
->pending
);
929 task_clear_jobctl_pending(t
, JOBCTL_STOP_PENDING
);
930 if (likely(!(t
->ptrace
& PT_SEIZED
)))
931 wake_up_state(t
, __TASK_STOPPED
);
933 ptrace_trap_notify(t
);
937 * Notify the parent with CLD_CONTINUED if we were stopped.
939 * If we were in the middle of a group stop, we pretend it
940 * was already finished, and then continued. Since SIGCHLD
941 * doesn't queue we report only CLD_STOPPED, as if the next
942 * CLD_CONTINUED was dropped.
945 if (signal
->flags
& SIGNAL_STOP_STOPPED
)
946 why
|= SIGNAL_CLD_CONTINUED
;
947 else if (signal
->group_stop_count
)
948 why
|= SIGNAL_CLD_STOPPED
;
952 * The first thread which returns from do_signal_stop()
953 * will take ->siglock, notice SIGNAL_CLD_MASK, and
954 * notify its parent. See get_signal().
956 signal_set_stop_flags(signal
, why
| SIGNAL_STOP_CONTINUED
);
957 signal
->group_stop_count
= 0;
958 signal
->group_exit_code
= 0;
962 return !sig_ignored(p
, sig
, force
);
966 * Test if P wants to take SIG. After we've checked all threads with this,
967 * it's equivalent to finding no threads not blocking SIG. Any threads not
968 * blocking SIG were ruled out because they are not running and already
969 * have pending signals. Such threads will dequeue from the shared queue
970 * as soon as they're available, so putting the signal on the shared queue
971 * will be equivalent to sending it to one such thread.
973 static inline bool wants_signal(int sig
, struct task_struct
*p
)
975 if (sigismember(&p
->blocked
, sig
))
978 if (p
->flags
& PF_EXITING
)
984 if (task_is_stopped_or_traced(p
))
987 return task_curr(p
) || !task_sigpending(p
);
990 static void complete_signal(int sig
, struct task_struct
*p
, enum pid_type type
)
992 struct signal_struct
*signal
= p
->signal
;
993 struct task_struct
*t
;
996 * Now find a thread we can wake up to take the signal off the queue.
998 * If the main thread wants the signal, it gets first crack.
999 * Probably the least surprising to the average bear.
1001 if (wants_signal(sig
, p
))
1003 else if ((type
== PIDTYPE_PID
) || thread_group_empty(p
))
1005 * There is just one thread and it does not need to be woken.
1006 * It will dequeue unblocked signals before it runs again.
1011 * Otherwise try to find a suitable thread.
1013 t
= signal
->curr_target
;
1014 while (!wants_signal(sig
, t
)) {
1016 if (t
== signal
->curr_target
)
1018 * No thread needs to be woken.
1019 * Any eligible threads will see
1020 * the signal in the queue soon.
1024 signal
->curr_target
= t
;
1028 * Found a killable thread. If the signal will be fatal,
1029 * then start taking the whole group down immediately.
1031 if (sig_fatal(p
, sig
) &&
1032 !(signal
->flags
& SIGNAL_GROUP_EXIT
) &&
1033 !sigismember(&t
->real_blocked
, sig
) &&
1034 (sig
== SIGKILL
|| !p
->ptrace
)) {
1036 * This signal will be fatal to the whole group.
1038 if (!sig_kernel_coredump(sig
)) {
1040 * Start a group exit and wake everybody up.
1041 * This way we don't have other threads
1042 * running and doing things after a slower
1043 * thread has the fatal signal pending.
1045 signal
->flags
= SIGNAL_GROUP_EXIT
;
1046 signal
->group_exit_code
= sig
;
1047 signal
->group_stop_count
= 0;
1050 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
1051 sigaddset(&t
->pending
.signal
, SIGKILL
);
1052 signal_wake_up(t
, 1);
1053 } while_each_thread(p
, t
);
1059 * The signal is already in the shared-pending queue.
1060 * Tell the chosen thread to wake up and dequeue it.
1062 signal_wake_up(t
, sig
== SIGKILL
);
1066 static inline bool legacy_queue(struct sigpending
*signals
, int sig
)
1068 return (sig
< SIGRTMIN
) && sigismember(&signals
->signal
, sig
);
1071 static int __send_signal(int sig
, struct kernel_siginfo
*info
, struct task_struct
*t
,
1072 enum pid_type type
, bool force
)
1074 struct sigpending
*pending
;
1076 int override_rlimit
;
1077 int ret
= 0, result
;
1079 assert_spin_locked(&t
->sighand
->siglock
);
1081 result
= TRACE_SIGNAL_IGNORED
;
1082 if (!prepare_signal(sig
, t
, force
))
1085 pending
= (type
!= PIDTYPE_PID
) ? &t
->signal
->shared_pending
: &t
->pending
;
1087 * Short-circuit ignored signals and support queuing
1088 * exactly one non-rt signal, so that we can get more
1089 * detailed information about the cause of the signal.
1091 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1092 if (legacy_queue(pending
, sig
))
1095 result
= TRACE_SIGNAL_DELIVERED
;
1097 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1099 if ((sig
== SIGKILL
) || (t
->flags
& PF_KTHREAD
))
1103 * Real-time signals must be queued if sent by sigqueue, or
1104 * some other real-time mechanism. It is implementation
1105 * defined whether kill() does so. We attempt to do so, on
1106 * the principle of least surprise, but since kill is not
1107 * allowed to fail with EAGAIN when low on memory we just
1108 * make sure at least one signal gets delivered and don't
1109 * pass on the info struct.
1112 override_rlimit
= (is_si_special(info
) || info
->si_code
>= 0);
1114 override_rlimit
= 0;
1116 q
= __sigqueue_alloc(sig
, t
, GFP_ATOMIC
, override_rlimit
, 0);
1119 list_add_tail(&q
->list
, &pending
->list
);
1120 switch ((unsigned long) info
) {
1121 case (unsigned long) SEND_SIG_NOINFO
:
1122 clear_siginfo(&q
->info
);
1123 q
->info
.si_signo
= sig
;
1124 q
->info
.si_errno
= 0;
1125 q
->info
.si_code
= SI_USER
;
1126 q
->info
.si_pid
= task_tgid_nr_ns(current
,
1127 task_active_pid_ns(t
));
1130 from_kuid_munged(task_cred_xxx(t
, user_ns
),
1134 case (unsigned long) SEND_SIG_PRIV
:
1135 clear_siginfo(&q
->info
);
1136 q
->info
.si_signo
= sig
;
1137 q
->info
.si_errno
= 0;
1138 q
->info
.si_code
= SI_KERNEL
;
1143 copy_siginfo(&q
->info
, info
);
1146 } else if (!is_si_special(info
) &&
1147 sig
>= SIGRTMIN
&& info
->si_code
!= SI_USER
) {
1149 * Queue overflow, abort. We may abort if the
1150 * signal was rt and sent by user using something
1151 * other than kill().
1153 result
= TRACE_SIGNAL_OVERFLOW_FAIL
;
1158 * This is a silent loss of information. We still
1159 * send the signal, but the *info bits are lost.
1161 result
= TRACE_SIGNAL_LOSE_INFO
;
1165 signalfd_notify(t
, sig
);
1166 sigaddset(&pending
->signal
, sig
);
1168 /* Let multiprocess signals appear after on-going forks */
1169 if (type
> PIDTYPE_TGID
) {
1170 struct multiprocess_signals
*delayed
;
1171 hlist_for_each_entry(delayed
, &t
->signal
->multiprocess
, node
) {
1172 sigset_t
*signal
= &delayed
->signal
;
1173 /* Can't queue both a stop and a continue signal */
1175 sigdelsetmask(signal
, SIG_KERNEL_STOP_MASK
);
1176 else if (sig_kernel_stop(sig
))
1177 sigdelset(signal
, SIGCONT
);
1178 sigaddset(signal
, sig
);
1182 complete_signal(sig
, t
, type
);
1184 trace_signal_generate(sig
, info
, t
, type
!= PIDTYPE_PID
, result
);
1188 static inline bool has_si_pid_and_uid(struct kernel_siginfo
*info
)
1191 switch (siginfo_layout(info
->si_signo
, info
->si_code
)) {
1200 case SIL_FAULT_TRAPNO
:
1201 case SIL_FAULT_MCEERR
:
1202 case SIL_FAULT_BNDERR
:
1203 case SIL_FAULT_PKUERR
:
1204 case SIL_FAULT_PERF_EVENT
:
1212 static int send_signal(int sig
, struct kernel_siginfo
*info
, struct task_struct
*t
,
1215 /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */
1218 if (info
== SEND_SIG_NOINFO
) {
1219 /* Force if sent from an ancestor pid namespace */
1220 force
= !task_pid_nr_ns(current
, task_active_pid_ns(t
));
1221 } else if (info
== SEND_SIG_PRIV
) {
1222 /* Don't ignore kernel generated signals */
1224 } else if (has_si_pid_and_uid(info
)) {
1225 /* SIGKILL and SIGSTOP is special or has ids */
1226 struct user_namespace
*t_user_ns
;
1229 t_user_ns
= task_cred_xxx(t
, user_ns
);
1230 if (current_user_ns() != t_user_ns
) {
1231 kuid_t uid
= make_kuid(current_user_ns(), info
->si_uid
);
1232 info
->si_uid
= from_kuid_munged(t_user_ns
, uid
);
1236 /* A kernel generated signal? */
1237 force
= (info
->si_code
== SI_KERNEL
);
1239 /* From an ancestor pid namespace? */
1240 if (!task_pid_nr_ns(current
, task_active_pid_ns(t
))) {
1245 return __send_signal(sig
, info
, t
, type
, force
);
1248 static void print_fatal_signal(int signr
)
1250 struct pt_regs
*regs
= signal_pt_regs();
1251 pr_info("potentially unexpected fatal signal %d.\n", signr
);
1253 #if defined(__i386__) && !defined(__arch_um__)
1254 pr_info("code at %08lx: ", regs
->ip
);
1257 for (i
= 0; i
< 16; i
++) {
1260 if (get_user(insn
, (unsigned char *)(regs
->ip
+ i
)))
1262 pr_cont("%02x ", insn
);
1272 static int __init
setup_print_fatal_signals(char *str
)
1274 get_option (&str
, &print_fatal_signals
);
1279 __setup("print-fatal-signals=", setup_print_fatal_signals
);
1282 __group_send_sig_info(int sig
, struct kernel_siginfo
*info
, struct task_struct
*p
)
1284 return send_signal(sig
, info
, p
, PIDTYPE_TGID
);
1287 int do_send_sig_info(int sig
, struct kernel_siginfo
*info
, struct task_struct
*p
,
1290 unsigned long flags
;
1293 if (lock_task_sighand(p
, &flags
)) {
1294 ret
= send_signal(sig
, info
, p
, type
);
1295 unlock_task_sighand(p
, &flags
);
1302 * Force a signal that the process can't ignore: if necessary
1303 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1305 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1306 * since we do not want to have a signal handler that was blocked
1307 * be invoked when user space had explicitly blocked it.
1309 * We don't want to have recursive SIGSEGV's etc, for example,
1310 * that is why we also clear SIGNAL_UNKILLABLE.
1313 force_sig_info_to_task(struct kernel_siginfo
*info
, struct task_struct
*t
, bool sigdfl
)
1315 unsigned long int flags
;
1316 int ret
, blocked
, ignored
;
1317 struct k_sigaction
*action
;
1318 int sig
= info
->si_signo
;
1320 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
1321 action
= &t
->sighand
->action
[sig
-1];
1322 ignored
= action
->sa
.sa_handler
== SIG_IGN
;
1323 blocked
= sigismember(&t
->blocked
, sig
);
1324 if (blocked
|| ignored
|| sigdfl
) {
1325 action
->sa
.sa_handler
= SIG_DFL
;
1326 action
->sa
.sa_flags
|= SA_IMMUTABLE
;
1328 sigdelset(&t
->blocked
, sig
);
1329 recalc_sigpending_and_wake(t
);
1333 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1334 * debugging to leave init killable.
1336 if (action
->sa
.sa_handler
== SIG_DFL
&& !t
->ptrace
)
1337 t
->signal
->flags
&= ~SIGNAL_UNKILLABLE
;
1338 ret
= send_signal(sig
, info
, t
, PIDTYPE_PID
);
1339 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
1344 int force_sig_info(struct kernel_siginfo
*info
)
1346 return force_sig_info_to_task(info
, current
, false);
1350 * Nuke all other threads in the group.
1352 int zap_other_threads(struct task_struct
*p
)
1354 struct task_struct
*t
= p
;
1357 p
->signal
->group_stop_count
= 0;
1359 while_each_thread(p
, t
) {
1360 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
1363 /* Don't bother with already dead threads */
1366 sigaddset(&t
->pending
.signal
, SIGKILL
);
1367 signal_wake_up(t
, 1);
1373 struct sighand_struct
*__lock_task_sighand(struct task_struct
*tsk
,
1374 unsigned long *flags
)
1376 struct sighand_struct
*sighand
;
1380 sighand
= rcu_dereference(tsk
->sighand
);
1381 if (unlikely(sighand
== NULL
))
1385 * This sighand can be already freed and even reused, but
1386 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1387 * initializes ->siglock: this slab can't go away, it has
1388 * the same object type, ->siglock can't be reinitialized.
1390 * We need to ensure that tsk->sighand is still the same
1391 * after we take the lock, we can race with de_thread() or
1392 * __exit_signal(). In the latter case the next iteration
1393 * must see ->sighand == NULL.
1395 spin_lock_irqsave(&sighand
->siglock
, *flags
);
1396 if (likely(sighand
== rcu_access_pointer(tsk
->sighand
)))
1398 spin_unlock_irqrestore(&sighand
->siglock
, *flags
);
1405 #ifdef CONFIG_LOCKDEP
1406 void lockdep_assert_task_sighand_held(struct task_struct
*task
)
1408 struct sighand_struct
*sighand
;
1411 sighand
= rcu_dereference(task
->sighand
);
1413 lockdep_assert_held(&sighand
->siglock
);
1421 * send signal info to all the members of a group
1423 int group_send_sig_info(int sig
, struct kernel_siginfo
*info
,
1424 struct task_struct
*p
, enum pid_type type
)
1429 ret
= check_kill_permission(sig
, info
, p
);
1433 ret
= do_send_sig_info(sig
, info
, p
, type
);
1439 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1440 * control characters do (^C, ^Z etc)
1441 * - the caller must hold at least a readlock on tasklist_lock
1443 int __kill_pgrp_info(int sig
, struct kernel_siginfo
*info
, struct pid
*pgrp
)
1445 struct task_struct
*p
= NULL
;
1446 int retval
, success
;
1450 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
1451 int err
= group_send_sig_info(sig
, info
, p
, PIDTYPE_PGID
);
1454 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
1455 return success
? 0 : retval
;
1458 int kill_pid_info(int sig
, struct kernel_siginfo
*info
, struct pid
*pid
)
1461 struct task_struct
*p
;
1465 p
= pid_task(pid
, PIDTYPE_PID
);
1467 error
= group_send_sig_info(sig
, info
, p
, PIDTYPE_TGID
);
1469 if (likely(!p
|| error
!= -ESRCH
))
1473 * The task was unhashed in between, try again. If it
1474 * is dead, pid_task() will return NULL, if we race with
1475 * de_thread() it will find the new leader.
1480 static int kill_proc_info(int sig
, struct kernel_siginfo
*info
, pid_t pid
)
1484 error
= kill_pid_info(sig
, info
, find_vpid(pid
));
1489 static inline bool kill_as_cred_perm(const struct cred
*cred
,
1490 struct task_struct
*target
)
1492 const struct cred
*pcred
= __task_cred(target
);
1494 return uid_eq(cred
->euid
, pcred
->suid
) ||
1495 uid_eq(cred
->euid
, pcred
->uid
) ||
1496 uid_eq(cred
->uid
, pcred
->suid
) ||
1497 uid_eq(cred
->uid
, pcred
->uid
);
1501 * The usb asyncio usage of siginfo is wrong. The glibc support
1502 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1503 * AKA after the generic fields:
1504 * kernel_pid_t si_pid;
1505 * kernel_uid32_t si_uid;
1506 * sigval_t si_value;
1508 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1509 * after the generic fields is:
1510 * void __user *si_addr;
1512 * This is a practical problem when there is a 64bit big endian kernel
1513 * and a 32bit userspace. As the 32bit address will encoded in the low
1514 * 32bits of the pointer. Those low 32bits will be stored at higher
1515 * address than appear in a 32 bit pointer. So userspace will not
1516 * see the address it was expecting for it's completions.
1518 * There is nothing in the encoding that can allow
1519 * copy_siginfo_to_user32 to detect this confusion of formats, so
1520 * handle this by requiring the caller of kill_pid_usb_asyncio to
1521 * notice when this situration takes place and to store the 32bit
1522 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1525 int kill_pid_usb_asyncio(int sig
, int errno
, sigval_t addr
,
1526 struct pid
*pid
, const struct cred
*cred
)
1528 struct kernel_siginfo info
;
1529 struct task_struct
*p
;
1530 unsigned long flags
;
1533 if (!valid_signal(sig
))
1536 clear_siginfo(&info
);
1537 info
.si_signo
= sig
;
1538 info
.si_errno
= errno
;
1539 info
.si_code
= SI_ASYNCIO
;
1540 *((sigval_t
*)&info
.si_pid
) = addr
;
1543 p
= pid_task(pid
, PIDTYPE_PID
);
1548 if (!kill_as_cred_perm(cred
, p
)) {
1552 ret
= security_task_kill(p
, &info
, sig
, cred
);
1557 if (lock_task_sighand(p
, &flags
)) {
1558 ret
= __send_signal(sig
, &info
, p
, PIDTYPE_TGID
, false);
1559 unlock_task_sighand(p
, &flags
);
1567 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio
);
1570 * kill_something_info() interprets pid in interesting ways just like kill(2).
1572 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1573 * is probably wrong. Should make it like BSD or SYSV.
1576 static int kill_something_info(int sig
, struct kernel_siginfo
*info
, pid_t pid
)
1581 return kill_proc_info(sig
, info
, pid
);
1583 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1587 read_lock(&tasklist_lock
);
1589 ret
= __kill_pgrp_info(sig
, info
,
1590 pid
? find_vpid(-pid
) : task_pgrp(current
));
1592 int retval
= 0, count
= 0;
1593 struct task_struct
* p
;
1595 for_each_process(p
) {
1596 if (task_pid_vnr(p
) > 1 &&
1597 !same_thread_group(p
, current
)) {
1598 int err
= group_send_sig_info(sig
, info
, p
,
1605 ret
= count
? retval
: -ESRCH
;
1607 read_unlock(&tasklist_lock
);
1613 * These are for backward compatibility with the rest of the kernel source.
1616 int send_sig_info(int sig
, struct kernel_siginfo
*info
, struct task_struct
*p
)
1619 * Make sure legacy kernel users don't send in bad values
1620 * (normal paths check this in check_kill_permission).
1622 if (!valid_signal(sig
))
1625 return do_send_sig_info(sig
, info
, p
, PIDTYPE_PID
);
1627 EXPORT_SYMBOL(send_sig_info
);
1629 #define __si_special(priv) \
1630 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1633 send_sig(int sig
, struct task_struct
*p
, int priv
)
1635 return send_sig_info(sig
, __si_special(priv
), p
);
1637 EXPORT_SYMBOL(send_sig
);
1639 void force_sig(int sig
)
1641 struct kernel_siginfo info
;
1643 clear_siginfo(&info
);
1644 info
.si_signo
= sig
;
1646 info
.si_code
= SI_KERNEL
;
1649 force_sig_info(&info
);
1651 EXPORT_SYMBOL(force_sig
);
1653 void force_fatal_sig(int sig
)
1655 struct kernel_siginfo info
;
1657 clear_siginfo(&info
);
1658 info
.si_signo
= sig
;
1660 info
.si_code
= SI_KERNEL
;
1663 force_sig_info_to_task(&info
, current
, true);
1667 * When things go south during signal handling, we
1668 * will force a SIGSEGV. And if the signal that caused
1669 * the problem was already a SIGSEGV, we'll want to
1670 * make sure we don't even try to deliver the signal..
1672 void force_sigsegv(int sig
)
1675 force_fatal_sig(SIGSEGV
);
1680 int force_sig_fault_to_task(int sig
, int code
, void __user
*addr
1681 ___ARCH_SI_IA64(int imm
, unsigned int flags
, unsigned long isr
)
1682 , struct task_struct
*t
)
1684 struct kernel_siginfo info
;
1686 clear_siginfo(&info
);
1687 info
.si_signo
= sig
;
1689 info
.si_code
= code
;
1690 info
.si_addr
= addr
;
1693 info
.si_flags
= flags
;
1696 return force_sig_info_to_task(&info
, t
, false);
1699 int force_sig_fault(int sig
, int code
, void __user
*addr
1700 ___ARCH_SI_IA64(int imm
, unsigned int flags
, unsigned long isr
))
1702 return force_sig_fault_to_task(sig
, code
, addr
1703 ___ARCH_SI_IA64(imm
, flags
, isr
), current
);
1706 int send_sig_fault(int sig
, int code
, void __user
*addr
1707 ___ARCH_SI_IA64(int imm
, unsigned int flags
, unsigned long isr
)
1708 , struct task_struct
*t
)
1710 struct kernel_siginfo info
;
1712 clear_siginfo(&info
);
1713 info
.si_signo
= sig
;
1715 info
.si_code
= code
;
1716 info
.si_addr
= addr
;
1719 info
.si_flags
= flags
;
1722 return send_sig_info(info
.si_signo
, &info
, t
);
1725 int force_sig_mceerr(int code
, void __user
*addr
, short lsb
)
1727 struct kernel_siginfo info
;
1729 WARN_ON((code
!= BUS_MCEERR_AO
) && (code
!= BUS_MCEERR_AR
));
1730 clear_siginfo(&info
);
1731 info
.si_signo
= SIGBUS
;
1733 info
.si_code
= code
;
1734 info
.si_addr
= addr
;
1735 info
.si_addr_lsb
= lsb
;
1736 return force_sig_info(&info
);
1739 int send_sig_mceerr(int code
, void __user
*addr
, short lsb
, struct task_struct
*t
)
1741 struct kernel_siginfo info
;
1743 WARN_ON((code
!= BUS_MCEERR_AO
) && (code
!= BUS_MCEERR_AR
));
1744 clear_siginfo(&info
);
1745 info
.si_signo
= SIGBUS
;
1747 info
.si_code
= code
;
1748 info
.si_addr
= addr
;
1749 info
.si_addr_lsb
= lsb
;
1750 return send_sig_info(info
.si_signo
, &info
, t
);
1752 EXPORT_SYMBOL(send_sig_mceerr
);
1754 int force_sig_bnderr(void __user
*addr
, void __user
*lower
, void __user
*upper
)
1756 struct kernel_siginfo info
;
1758 clear_siginfo(&info
);
1759 info
.si_signo
= SIGSEGV
;
1761 info
.si_code
= SEGV_BNDERR
;
1762 info
.si_addr
= addr
;
1763 info
.si_lower
= lower
;
1764 info
.si_upper
= upper
;
1765 return force_sig_info(&info
);
1769 int force_sig_pkuerr(void __user
*addr
, u32 pkey
)
1771 struct kernel_siginfo info
;
1773 clear_siginfo(&info
);
1774 info
.si_signo
= SIGSEGV
;
1776 info
.si_code
= SEGV_PKUERR
;
1777 info
.si_addr
= addr
;
1778 info
.si_pkey
= pkey
;
1779 return force_sig_info(&info
);
1783 int force_sig_perf(void __user
*addr
, u32 type
, u64 sig_data
)
1785 struct kernel_siginfo info
;
1787 clear_siginfo(&info
);
1788 info
.si_signo
= SIGTRAP
;
1790 info
.si_code
= TRAP_PERF
;
1791 info
.si_addr
= addr
;
1792 info
.si_perf_data
= sig_data
;
1793 info
.si_perf_type
= type
;
1795 return force_sig_info(&info
);
1799 * force_sig_seccomp - signals the task to allow in-process syscall emulation
1800 * @syscall: syscall number to send to userland
1801 * @reason: filter-supplied reason code to send to userland (via si_errno)
1803 * Forces a SIGSYS with a code of SYS_SECCOMP and related sigsys info.
1805 int force_sig_seccomp(int syscall
, int reason
, bool force_coredump
)
1807 struct kernel_siginfo info
;
1809 clear_siginfo(&info
);
1810 info
.si_signo
= SIGSYS
;
1811 info
.si_code
= SYS_SECCOMP
;
1812 info
.si_call_addr
= (void __user
*)KSTK_EIP(current
);
1813 info
.si_errno
= reason
;
1814 info
.si_arch
= syscall_get_arch(current
);
1815 info
.si_syscall
= syscall
;
1816 return force_sig_info_to_task(&info
, current
, force_coredump
);
1819 /* For the crazy architectures that include trap information in
1820 * the errno field, instead of an actual errno value.
1822 int force_sig_ptrace_errno_trap(int errno
, void __user
*addr
)
1824 struct kernel_siginfo info
;
1826 clear_siginfo(&info
);
1827 info
.si_signo
= SIGTRAP
;
1828 info
.si_errno
= errno
;
1829 info
.si_code
= TRAP_HWBKPT
;
1830 info
.si_addr
= addr
;
1831 return force_sig_info(&info
);
1834 /* For the rare architectures that include trap information using
1837 int force_sig_fault_trapno(int sig
, int code
, void __user
*addr
, int trapno
)
1839 struct kernel_siginfo info
;
1841 clear_siginfo(&info
);
1842 info
.si_signo
= sig
;
1844 info
.si_code
= code
;
1845 info
.si_addr
= addr
;
1846 info
.si_trapno
= trapno
;
1847 return force_sig_info(&info
);
1850 /* For the rare architectures that include trap information using
1853 int send_sig_fault_trapno(int sig
, int code
, void __user
*addr
, int trapno
,
1854 struct task_struct
*t
)
1856 struct kernel_siginfo info
;
1858 clear_siginfo(&info
);
1859 info
.si_signo
= sig
;
1861 info
.si_code
= code
;
1862 info
.si_addr
= addr
;
1863 info
.si_trapno
= trapno
;
1864 return send_sig_info(info
.si_signo
, &info
, t
);
1867 int kill_pgrp(struct pid
*pid
, int sig
, int priv
)
1871 read_lock(&tasklist_lock
);
1872 ret
= __kill_pgrp_info(sig
, __si_special(priv
), pid
);
1873 read_unlock(&tasklist_lock
);
1877 EXPORT_SYMBOL(kill_pgrp
);
1879 int kill_pid(struct pid
*pid
, int sig
, int priv
)
1881 return kill_pid_info(sig
, __si_special(priv
), pid
);
1883 EXPORT_SYMBOL(kill_pid
);
1886 * These functions support sending signals using preallocated sigqueue
1887 * structures. This is needed "because realtime applications cannot
1888 * afford to lose notifications of asynchronous events, like timer
1889 * expirations or I/O completions". In the case of POSIX Timers
1890 * we allocate the sigqueue structure from the timer_create. If this
1891 * allocation fails we are able to report the failure to the application
1892 * with an EAGAIN error.
1894 struct sigqueue
*sigqueue_alloc(void)
1896 return __sigqueue_alloc(-1, current
, GFP_KERNEL
, 0, SIGQUEUE_PREALLOC
);
1899 void sigqueue_free(struct sigqueue
*q
)
1901 unsigned long flags
;
1902 spinlock_t
*lock
= ¤t
->sighand
->siglock
;
1904 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1906 * We must hold ->siglock while testing q->list
1907 * to serialize with collect_signal() or with
1908 * __exit_signal()->flush_sigqueue().
1910 spin_lock_irqsave(lock
, flags
);
1911 q
->flags
&= ~SIGQUEUE_PREALLOC
;
1913 * If it is queued it will be freed when dequeued,
1914 * like the "regular" sigqueue.
1916 if (!list_empty(&q
->list
))
1918 spin_unlock_irqrestore(lock
, flags
);
1924 int send_sigqueue(struct sigqueue
*q
, struct pid
*pid
, enum pid_type type
)
1926 int sig
= q
->info
.si_signo
;
1927 struct sigpending
*pending
;
1928 struct task_struct
*t
;
1929 unsigned long flags
;
1932 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1936 t
= pid_task(pid
, type
);
1937 if (!t
|| !likely(lock_task_sighand(t
, &flags
)))
1940 ret
= 1; /* the signal is ignored */
1941 result
= TRACE_SIGNAL_IGNORED
;
1942 if (!prepare_signal(sig
, t
, false))
1946 if (unlikely(!list_empty(&q
->list
))) {
1948 * If an SI_TIMER entry is already queue just increment
1949 * the overrun count.
1951 BUG_ON(q
->info
.si_code
!= SI_TIMER
);
1952 q
->info
.si_overrun
++;
1953 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1956 q
->info
.si_overrun
= 0;
1958 signalfd_notify(t
, sig
);
1959 pending
= (type
!= PIDTYPE_PID
) ? &t
->signal
->shared_pending
: &t
->pending
;
1960 list_add_tail(&q
->list
, &pending
->list
);
1961 sigaddset(&pending
->signal
, sig
);
1962 complete_signal(sig
, t
, type
);
1963 result
= TRACE_SIGNAL_DELIVERED
;
1965 trace_signal_generate(sig
, &q
->info
, t
, type
!= PIDTYPE_PID
, result
);
1966 unlock_task_sighand(t
, &flags
);
1972 static void do_notify_pidfd(struct task_struct
*task
)
1976 WARN_ON(task
->exit_state
== 0);
1977 pid
= task_pid(task
);
1978 wake_up_all(&pid
->wait_pidfd
);
1982 * Let a parent know about the death of a child.
1983 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1985 * Returns true if our parent ignored us and so we've switched to
1988 bool do_notify_parent(struct task_struct
*tsk
, int sig
)
1990 struct kernel_siginfo info
;
1991 unsigned long flags
;
1992 struct sighand_struct
*psig
;
1993 bool autoreap
= false;
1998 /* do_notify_parent_cldstop should have been called instead. */
1999 BUG_ON(task_is_stopped_or_traced(tsk
));
2001 BUG_ON(!tsk
->ptrace
&&
2002 (tsk
->group_leader
!= tsk
|| !thread_group_empty(tsk
)));
2004 /* Wake up all pidfd waiters */
2005 do_notify_pidfd(tsk
);
2007 if (sig
!= SIGCHLD
) {
2009 * This is only possible if parent == real_parent.
2010 * Check if it has changed security domain.
2012 if (tsk
->parent_exec_id
!= READ_ONCE(tsk
->parent
->self_exec_id
))
2016 clear_siginfo(&info
);
2017 info
.si_signo
= sig
;
2020 * We are under tasklist_lock here so our parent is tied to
2021 * us and cannot change.
2023 * task_active_pid_ns will always return the same pid namespace
2024 * until a task passes through release_task.
2026 * write_lock() currently calls preempt_disable() which is the
2027 * same as rcu_read_lock(), but according to Oleg, this is not
2028 * correct to rely on this
2031 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(tsk
->parent
));
2032 info
.si_uid
= from_kuid_munged(task_cred_xxx(tsk
->parent
, user_ns
),
2036 task_cputime(tsk
, &utime
, &stime
);
2037 info
.si_utime
= nsec_to_clock_t(utime
+ tsk
->signal
->utime
);
2038 info
.si_stime
= nsec_to_clock_t(stime
+ tsk
->signal
->stime
);
2040 info
.si_status
= tsk
->exit_code
& 0x7f;
2041 if (tsk
->exit_code
& 0x80)
2042 info
.si_code
= CLD_DUMPED
;
2043 else if (tsk
->exit_code
& 0x7f)
2044 info
.si_code
= CLD_KILLED
;
2046 info
.si_code
= CLD_EXITED
;
2047 info
.si_status
= tsk
->exit_code
>> 8;
2050 psig
= tsk
->parent
->sighand
;
2051 spin_lock_irqsave(&psig
->siglock
, flags
);
2052 if (!tsk
->ptrace
&& sig
== SIGCHLD
&&
2053 (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
||
2054 (psig
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDWAIT
))) {
2056 * We are exiting and our parent doesn't care. POSIX.1
2057 * defines special semantics for setting SIGCHLD to SIG_IGN
2058 * or setting the SA_NOCLDWAIT flag: we should be reaped
2059 * automatically and not left for our parent's wait4 call.
2060 * Rather than having the parent do it as a magic kind of
2061 * signal handler, we just set this to tell do_exit that we
2062 * can be cleaned up without becoming a zombie. Note that
2063 * we still call __wake_up_parent in this case, because a
2064 * blocked sys_wait4 might now return -ECHILD.
2066 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
2067 * is implementation-defined: we do (if you don't want
2068 * it, just use SIG_IGN instead).
2071 if (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
)
2075 * Send with __send_signal as si_pid and si_uid are in the
2076 * parent's namespaces.
2078 if (valid_signal(sig
) && sig
)
2079 __send_signal(sig
, &info
, tsk
->parent
, PIDTYPE_TGID
, false);
2080 __wake_up_parent(tsk
, tsk
->parent
);
2081 spin_unlock_irqrestore(&psig
->siglock
, flags
);
2087 * do_notify_parent_cldstop - notify parent of stopped/continued state change
2088 * @tsk: task reporting the state change
2089 * @for_ptracer: the notification is for ptracer
2090 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
2092 * Notify @tsk's parent that the stopped/continued state has changed. If
2093 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
2094 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
2097 * Must be called with tasklist_lock at least read locked.
2099 static void do_notify_parent_cldstop(struct task_struct
*tsk
,
2100 bool for_ptracer
, int why
)
2102 struct kernel_siginfo info
;
2103 unsigned long flags
;
2104 struct task_struct
*parent
;
2105 struct sighand_struct
*sighand
;
2109 parent
= tsk
->parent
;
2111 tsk
= tsk
->group_leader
;
2112 parent
= tsk
->real_parent
;
2115 clear_siginfo(&info
);
2116 info
.si_signo
= SIGCHLD
;
2119 * see comment in do_notify_parent() about the following 4 lines
2122 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(parent
));
2123 info
.si_uid
= from_kuid_munged(task_cred_xxx(parent
, user_ns
), task_uid(tsk
));
2126 task_cputime(tsk
, &utime
, &stime
);
2127 info
.si_utime
= nsec_to_clock_t(utime
);
2128 info
.si_stime
= nsec_to_clock_t(stime
);
2133 info
.si_status
= SIGCONT
;
2136 info
.si_status
= tsk
->signal
->group_exit_code
& 0x7f;
2139 info
.si_status
= tsk
->exit_code
& 0x7f;
2145 sighand
= parent
->sighand
;
2146 spin_lock_irqsave(&sighand
->siglock
, flags
);
2147 if (sighand
->action
[SIGCHLD
-1].sa
.sa_handler
!= SIG_IGN
&&
2148 !(sighand
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDSTOP
))
2149 __group_send_sig_info(SIGCHLD
, &info
, parent
);
2151 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2153 __wake_up_parent(tsk
, parent
);
2154 spin_unlock_irqrestore(&sighand
->siglock
, flags
);
2157 static inline bool may_ptrace_stop(void)
2159 if (!likely(current
->ptrace
))
2162 * Are we in the middle of do_coredump?
2163 * If so and our tracer is also part of the coredump stopping
2164 * is a deadlock situation, and pointless because our tracer
2165 * is dead so don't allow us to stop.
2166 * If SIGKILL was already sent before the caller unlocked
2167 * ->siglock we must see ->core_state != NULL. Otherwise it
2168 * is safe to enter schedule().
2170 * This is almost outdated, a task with the pending SIGKILL can't
2171 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2172 * after SIGKILL was already dequeued.
2174 if (unlikely(current
->mm
->core_state
) &&
2175 unlikely(current
->mm
== current
->parent
->mm
))
2183 * This must be called with current->sighand->siglock held.
2185 * This should be the path for all ptrace stops.
2186 * We always set current->last_siginfo while stopped here.
2187 * That makes it a way to test a stopped process for
2188 * being ptrace-stopped vs being job-control-stopped.
2190 * If we actually decide not to stop at all because the tracer
2191 * is gone, we keep current->exit_code unless clear_code.
2193 static void ptrace_stop(int exit_code
, int why
, int clear_code
, kernel_siginfo_t
*info
)
2194 __releases(¤t
->sighand
->siglock
)
2195 __acquires(¤t
->sighand
->siglock
)
2197 bool gstop_done
= false;
2199 if (arch_ptrace_stop_needed(exit_code
, info
)) {
2201 * The arch code has something special to do before a
2202 * ptrace stop. This is allowed to block, e.g. for faults
2203 * on user stack pages. We can't keep the siglock while
2204 * calling arch_ptrace_stop, so we must release it now.
2205 * To preserve proper semantics, we must do this before
2206 * any signal bookkeeping like checking group_stop_count.
2208 spin_unlock_irq(¤t
->sighand
->siglock
);
2209 arch_ptrace_stop(exit_code
, info
);
2210 spin_lock_irq(¤t
->sighand
->siglock
);
2214 * schedule() will not sleep if there is a pending signal that
2215 * can awaken the task.
2217 set_special_state(TASK_TRACED
);
2220 * We're committing to trapping. TRACED should be visible before
2221 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2222 * Also, transition to TRACED and updates to ->jobctl should be
2223 * atomic with respect to siglock and should be done after the arch
2224 * hook as siglock is released and regrabbed across it.
2229 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2231 * set_current_state() smp_wmb();
2233 * wait_task_stopped()
2234 * task_stopped_code()
2235 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2239 current
->last_siginfo
= info
;
2240 current
->exit_code
= exit_code
;
2243 * If @why is CLD_STOPPED, we're trapping to participate in a group
2244 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2245 * across siglock relocks since INTERRUPT was scheduled, PENDING
2246 * could be clear now. We act as if SIGCONT is received after
2247 * TASK_TRACED is entered - ignore it.
2249 if (why
== CLD_STOPPED
&& (current
->jobctl
& JOBCTL_STOP_PENDING
))
2250 gstop_done
= task_participate_group_stop(current
);
2252 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2253 task_clear_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
2254 if (info
&& info
->si_code
>> 8 == PTRACE_EVENT_STOP
)
2255 task_clear_jobctl_pending(current
, JOBCTL_TRAP_NOTIFY
);
2257 /* entering a trap, clear TRAPPING */
2258 task_clear_jobctl_trapping(current
);
2260 spin_unlock_irq(¤t
->sighand
->siglock
);
2261 read_lock(&tasklist_lock
);
2262 if (may_ptrace_stop()) {
2264 * Notify parents of the stop.
2266 * While ptraced, there are two parents - the ptracer and
2267 * the real_parent of the group_leader. The ptracer should
2268 * know about every stop while the real parent is only
2269 * interested in the completion of group stop. The states
2270 * for the two don't interact with each other. Notify
2271 * separately unless they're gonna be duplicates.
2273 do_notify_parent_cldstop(current
, true, why
);
2274 if (gstop_done
&& ptrace_reparented(current
))
2275 do_notify_parent_cldstop(current
, false, why
);
2278 * Don't want to allow preemption here, because
2279 * sys_ptrace() needs this task to be inactive.
2281 * XXX: implement read_unlock_no_resched().
2284 read_unlock(&tasklist_lock
);
2285 cgroup_enter_frozen();
2286 preempt_enable_no_resched();
2287 freezable_schedule();
2288 cgroup_leave_frozen(true);
2291 * By the time we got the lock, our tracer went away.
2292 * Don't drop the lock yet, another tracer may come.
2294 * If @gstop_done, the ptracer went away between group stop
2295 * completion and here. During detach, it would have set
2296 * JOBCTL_STOP_PENDING on us and we'll re-enter
2297 * TASK_STOPPED in do_signal_stop() on return, so notifying
2298 * the real parent of the group stop completion is enough.
2301 do_notify_parent_cldstop(current
, false, why
);
2303 /* tasklist protects us from ptrace_freeze_traced() */
2304 __set_current_state(TASK_RUNNING
);
2306 current
->exit_code
= 0;
2307 read_unlock(&tasklist_lock
);
2311 * We are back. Now reacquire the siglock before touching
2312 * last_siginfo, so that we are sure to have synchronized with
2313 * any signal-sending on another CPU that wants to examine it.
2315 spin_lock_irq(¤t
->sighand
->siglock
);
2316 current
->last_siginfo
= NULL
;
2318 /* LISTENING can be set only during STOP traps, clear it */
2319 current
->jobctl
&= ~JOBCTL_LISTENING
;
2322 * Queued signals ignored us while we were stopped for tracing.
2323 * So check for any that we should take before resuming user mode.
2324 * This sets TIF_SIGPENDING, but never clears it.
2326 recalc_sigpending_tsk(current
);
2329 static void ptrace_do_notify(int signr
, int exit_code
, int why
)
2331 kernel_siginfo_t info
;
2333 clear_siginfo(&info
);
2334 info
.si_signo
= signr
;
2335 info
.si_code
= exit_code
;
2336 info
.si_pid
= task_pid_vnr(current
);
2337 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
2339 /* Let the debugger run. */
2340 ptrace_stop(exit_code
, why
, 1, &info
);
2343 void ptrace_notify(int exit_code
)
2345 BUG_ON((exit_code
& (0x7f | ~0xffff)) != SIGTRAP
);
2346 if (unlikely(current
->task_works
))
2349 spin_lock_irq(¤t
->sighand
->siglock
);
2350 ptrace_do_notify(SIGTRAP
, exit_code
, CLD_TRAPPED
);
2351 spin_unlock_irq(¤t
->sighand
->siglock
);
2355 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2356 * @signr: signr causing group stop if initiating
2358 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2359 * and participate in it. If already set, participate in the existing
2360 * group stop. If participated in a group stop (and thus slept), %true is
2361 * returned with siglock released.
2363 * If ptraced, this function doesn't handle stop itself. Instead,
2364 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2365 * untouched. The caller must ensure that INTERRUPT trap handling takes
2366 * places afterwards.
2369 * Must be called with @current->sighand->siglock held, which is released
2373 * %false if group stop is already cancelled or ptrace trap is scheduled.
2374 * %true if participated in group stop.
2376 static bool do_signal_stop(int signr
)
2377 __releases(¤t
->sighand
->siglock
)
2379 struct signal_struct
*sig
= current
->signal
;
2381 if (!(current
->jobctl
& JOBCTL_STOP_PENDING
)) {
2382 unsigned long gstop
= JOBCTL_STOP_PENDING
| JOBCTL_STOP_CONSUME
;
2383 struct task_struct
*t
;
2385 /* signr will be recorded in task->jobctl for retries */
2386 WARN_ON_ONCE(signr
& ~JOBCTL_STOP_SIGMASK
);
2388 if (!likely(current
->jobctl
& JOBCTL_STOP_DEQUEUED
) ||
2389 unlikely(signal_group_exit(sig
)))
2392 * There is no group stop already in progress. We must
2395 * While ptraced, a task may be resumed while group stop is
2396 * still in effect and then receive a stop signal and
2397 * initiate another group stop. This deviates from the
2398 * usual behavior as two consecutive stop signals can't
2399 * cause two group stops when !ptraced. That is why we
2400 * also check !task_is_stopped(t) below.
2402 * The condition can be distinguished by testing whether
2403 * SIGNAL_STOP_STOPPED is already set. Don't generate
2404 * group_exit_code in such case.
2406 * This is not necessary for SIGNAL_STOP_CONTINUED because
2407 * an intervening stop signal is required to cause two
2408 * continued events regardless of ptrace.
2410 if (!(sig
->flags
& SIGNAL_STOP_STOPPED
))
2411 sig
->group_exit_code
= signr
;
2413 sig
->group_stop_count
= 0;
2415 if (task_set_jobctl_pending(current
, signr
| gstop
))
2416 sig
->group_stop_count
++;
2419 while_each_thread(current
, t
) {
2421 * Setting state to TASK_STOPPED for a group
2422 * stop is always done with the siglock held,
2423 * so this check has no races.
2425 if (!task_is_stopped(t
) &&
2426 task_set_jobctl_pending(t
, signr
| gstop
)) {
2427 sig
->group_stop_count
++;
2428 if (likely(!(t
->ptrace
& PT_SEIZED
)))
2429 signal_wake_up(t
, 0);
2431 ptrace_trap_notify(t
);
2436 if (likely(!current
->ptrace
)) {
2440 * If there are no other threads in the group, or if there
2441 * is a group stop in progress and we are the last to stop,
2442 * report to the parent.
2444 if (task_participate_group_stop(current
))
2445 notify
= CLD_STOPPED
;
2447 set_special_state(TASK_STOPPED
);
2448 spin_unlock_irq(¤t
->sighand
->siglock
);
2451 * Notify the parent of the group stop completion. Because
2452 * we're not holding either the siglock or tasklist_lock
2453 * here, ptracer may attach inbetween; however, this is for
2454 * group stop and should always be delivered to the real
2455 * parent of the group leader. The new ptracer will get
2456 * its notification when this task transitions into
2460 read_lock(&tasklist_lock
);
2461 do_notify_parent_cldstop(current
, false, notify
);
2462 read_unlock(&tasklist_lock
);
2465 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2466 cgroup_enter_frozen();
2467 freezable_schedule();
2471 * While ptraced, group stop is handled by STOP trap.
2472 * Schedule it and let the caller deal with it.
2474 task_set_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
2480 * do_jobctl_trap - take care of ptrace jobctl traps
2482 * When PT_SEIZED, it's used for both group stop and explicit
2483 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2484 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2485 * the stop signal; otherwise, %SIGTRAP.
2487 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2488 * number as exit_code and no siginfo.
2491 * Must be called with @current->sighand->siglock held, which may be
2492 * released and re-acquired before returning with intervening sleep.
2494 static void do_jobctl_trap(void)
2496 struct signal_struct
*signal
= current
->signal
;
2497 int signr
= current
->jobctl
& JOBCTL_STOP_SIGMASK
;
2499 if (current
->ptrace
& PT_SEIZED
) {
2500 if (!signal
->group_stop_count
&&
2501 !(signal
->flags
& SIGNAL_STOP_STOPPED
))
2503 WARN_ON_ONCE(!signr
);
2504 ptrace_do_notify(signr
, signr
| (PTRACE_EVENT_STOP
<< 8),
2507 WARN_ON_ONCE(!signr
);
2508 ptrace_stop(signr
, CLD_STOPPED
, 0, NULL
);
2509 current
->exit_code
= 0;
2514 * do_freezer_trap - handle the freezer jobctl trap
2516 * Puts the task into frozen state, if only the task is not about to quit.
2517 * In this case it drops JOBCTL_TRAP_FREEZE.
2520 * Must be called with @current->sighand->siglock held,
2521 * which is always released before returning.
2523 static void do_freezer_trap(void)
2524 __releases(¤t
->sighand
->siglock
)
2527 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2528 * let's make another loop to give it a chance to be handled.
2529 * In any case, we'll return back.
2531 if ((current
->jobctl
& (JOBCTL_PENDING_MASK
| JOBCTL_TRAP_FREEZE
)) !=
2532 JOBCTL_TRAP_FREEZE
) {
2533 spin_unlock_irq(¤t
->sighand
->siglock
);
2538 * Now we're sure that there is no pending fatal signal and no
2539 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2540 * immediately (if there is a non-fatal signal pending), and
2541 * put the task into sleep.
2543 __set_current_state(TASK_INTERRUPTIBLE
);
2544 clear_thread_flag(TIF_SIGPENDING
);
2545 spin_unlock_irq(¤t
->sighand
->siglock
);
2546 cgroup_enter_frozen();
2547 freezable_schedule();
2550 static int ptrace_signal(int signr
, kernel_siginfo_t
*info
)
2553 * We do not check sig_kernel_stop(signr) but set this marker
2554 * unconditionally because we do not know whether debugger will
2555 * change signr. This flag has no meaning unless we are going
2556 * to stop after return from ptrace_stop(). In this case it will
2557 * be checked in do_signal_stop(), we should only stop if it was
2558 * not cleared by SIGCONT while we were sleeping. See also the
2559 * comment in dequeue_signal().
2561 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
2562 ptrace_stop(signr
, CLD_TRAPPED
, 0, info
);
2564 /* We're back. Did the debugger cancel the sig? */
2565 signr
= current
->exit_code
;
2569 current
->exit_code
= 0;
2572 * Update the siginfo structure if the signal has
2573 * changed. If the debugger wanted something
2574 * specific in the siginfo structure then it should
2575 * have updated *info via PTRACE_SETSIGINFO.
2577 if (signr
!= info
->si_signo
) {
2578 clear_siginfo(info
);
2579 info
->si_signo
= signr
;
2581 info
->si_code
= SI_USER
;
2583 info
->si_pid
= task_pid_vnr(current
->parent
);
2584 info
->si_uid
= from_kuid_munged(current_user_ns(),
2585 task_uid(current
->parent
));
2589 /* If the (new) signal is now blocked, requeue it. */
2590 if (sigismember(¤t
->blocked
, signr
)) {
2591 send_signal(signr
, info
, current
, PIDTYPE_PID
);
2598 static void hide_si_addr_tag_bits(struct ksignal
*ksig
)
2600 switch (siginfo_layout(ksig
->sig
, ksig
->info
.si_code
)) {
2602 case SIL_FAULT_TRAPNO
:
2603 case SIL_FAULT_MCEERR
:
2604 case SIL_FAULT_BNDERR
:
2605 case SIL_FAULT_PKUERR
:
2606 case SIL_FAULT_PERF_EVENT
:
2607 ksig
->info
.si_addr
= arch_untagged_si_addr(
2608 ksig
->info
.si_addr
, ksig
->sig
, ksig
->info
.si_code
);
2620 bool get_signal(struct ksignal
*ksig
)
2622 struct sighand_struct
*sighand
= current
->sighand
;
2623 struct signal_struct
*signal
= current
->signal
;
2626 if (unlikely(current
->task_works
))
2630 * For non-generic architectures, check for TIF_NOTIFY_SIGNAL so
2631 * that the arch handlers don't all have to do it. If we get here
2632 * without TIF_SIGPENDING, just exit after running signal work.
2634 if (!IS_ENABLED(CONFIG_GENERIC_ENTRY
)) {
2635 if (test_thread_flag(TIF_NOTIFY_SIGNAL
))
2636 tracehook_notify_signal();
2637 if (!task_sigpending(current
))
2641 if (unlikely(uprobe_deny_signal()))
2645 * Do this once, we can't return to user-mode if freezing() == T.
2646 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2647 * thus do not need another check after return.
2652 spin_lock_irq(&sighand
->siglock
);
2655 * Every stopped thread goes here after wakeup. Check to see if
2656 * we should notify the parent, prepare_signal(SIGCONT) encodes
2657 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2659 if (unlikely(signal
->flags
& SIGNAL_CLD_MASK
)) {
2662 if (signal
->flags
& SIGNAL_CLD_CONTINUED
)
2663 why
= CLD_CONTINUED
;
2667 signal
->flags
&= ~SIGNAL_CLD_MASK
;
2669 spin_unlock_irq(&sighand
->siglock
);
2672 * Notify the parent that we're continuing. This event is
2673 * always per-process and doesn't make whole lot of sense
2674 * for ptracers, who shouldn't consume the state via
2675 * wait(2) either, but, for backward compatibility, notify
2676 * the ptracer of the group leader too unless it's gonna be
2679 read_lock(&tasklist_lock
);
2680 do_notify_parent_cldstop(current
, false, why
);
2682 if (ptrace_reparented(current
->group_leader
))
2683 do_notify_parent_cldstop(current
->group_leader
,
2685 read_unlock(&tasklist_lock
);
2690 /* Has this task already been marked for death? */
2691 if (signal_group_exit(signal
)) {
2692 ksig
->info
.si_signo
= signr
= SIGKILL
;
2693 sigdelset(¤t
->pending
.signal
, SIGKILL
);
2694 trace_signal_deliver(SIGKILL
, SEND_SIG_NOINFO
,
2695 &sighand
->action
[SIGKILL
- 1]);
2696 recalc_sigpending();
2701 struct k_sigaction
*ka
;
2703 if (unlikely(current
->jobctl
& JOBCTL_STOP_PENDING
) &&
2707 if (unlikely(current
->jobctl
&
2708 (JOBCTL_TRAP_MASK
| JOBCTL_TRAP_FREEZE
))) {
2709 if (current
->jobctl
& JOBCTL_TRAP_MASK
) {
2711 spin_unlock_irq(&sighand
->siglock
);
2712 } else if (current
->jobctl
& JOBCTL_TRAP_FREEZE
)
2719 * If the task is leaving the frozen state, let's update
2720 * cgroup counters and reset the frozen bit.
2722 if (unlikely(cgroup_task_frozen(current
))) {
2723 spin_unlock_irq(&sighand
->siglock
);
2724 cgroup_leave_frozen(false);
2729 * Signals generated by the execution of an instruction
2730 * need to be delivered before any other pending signals
2731 * so that the instruction pointer in the signal stack
2732 * frame points to the faulting instruction.
2734 signr
= dequeue_synchronous_signal(&ksig
->info
);
2736 signr
= dequeue_signal(current
, ¤t
->blocked
, &ksig
->info
);
2739 break; /* will return 0 */
2741 if (unlikely(current
->ptrace
) && (signr
!= SIGKILL
) &&
2742 !(sighand
->action
[signr
-1].sa
.sa_flags
& SA_IMMUTABLE
)) {
2743 signr
= ptrace_signal(signr
, &ksig
->info
);
2748 ka
= &sighand
->action
[signr
-1];
2750 /* Trace actually delivered signals. */
2751 trace_signal_deliver(signr
, &ksig
->info
, ka
);
2753 if (ka
->sa
.sa_handler
== SIG_IGN
) /* Do nothing. */
2755 if (ka
->sa
.sa_handler
!= SIG_DFL
) {
2756 /* Run the handler. */
2759 if (ka
->sa
.sa_flags
& SA_ONESHOT
)
2760 ka
->sa
.sa_handler
= SIG_DFL
;
2762 break; /* will return non-zero "signr" value */
2766 * Now we are doing the default action for this signal.
2768 if (sig_kernel_ignore(signr
)) /* Default is nothing. */
2772 * Global init gets no signals it doesn't want.
2773 * Container-init gets no signals it doesn't want from same
2776 * Note that if global/container-init sees a sig_kernel_only()
2777 * signal here, the signal must have been generated internally
2778 * or must have come from an ancestor namespace. In either
2779 * case, the signal cannot be dropped.
2781 if (unlikely(signal
->flags
& SIGNAL_UNKILLABLE
) &&
2782 !sig_kernel_only(signr
))
2785 if (sig_kernel_stop(signr
)) {
2787 * The default action is to stop all threads in
2788 * the thread group. The job control signals
2789 * do nothing in an orphaned pgrp, but SIGSTOP
2790 * always works. Note that siglock needs to be
2791 * dropped during the call to is_orphaned_pgrp()
2792 * because of lock ordering with tasklist_lock.
2793 * This allows an intervening SIGCONT to be posted.
2794 * We need to check for that and bail out if necessary.
2796 if (signr
!= SIGSTOP
) {
2797 spin_unlock_irq(&sighand
->siglock
);
2799 /* signals can be posted during this window */
2801 if (is_current_pgrp_orphaned())
2804 spin_lock_irq(&sighand
->siglock
);
2807 if (likely(do_signal_stop(ksig
->info
.si_signo
))) {
2808 /* It released the siglock. */
2813 * We didn't actually stop, due to a race
2814 * with SIGCONT or something like that.
2820 spin_unlock_irq(&sighand
->siglock
);
2821 if (unlikely(cgroup_task_frozen(current
)))
2822 cgroup_leave_frozen(true);
2825 * Anything else is fatal, maybe with a core dump.
2827 current
->flags
|= PF_SIGNALED
;
2829 if (sig_kernel_coredump(signr
)) {
2830 if (print_fatal_signals
)
2831 print_fatal_signal(ksig
->info
.si_signo
);
2832 proc_coredump_connector(current
);
2834 * If it was able to dump core, this kills all
2835 * other threads in the group and synchronizes with
2836 * their demise. If we lost the race with another
2837 * thread getting here, it set group_exit_code
2838 * first and our do_group_exit call below will use
2839 * that value and ignore the one we pass it.
2841 do_coredump(&ksig
->info
);
2845 * PF_IO_WORKER threads will catch and exit on fatal signals
2846 * themselves. They have cleanup that must be performed, so
2847 * we cannot call do_exit() on their behalf.
2849 if (current
->flags
& PF_IO_WORKER
)
2853 * Death signals, no core dump.
2855 do_group_exit(ksig
->info
.si_signo
);
2858 spin_unlock_irq(&sighand
->siglock
);
2862 if (!(ksig
->ka
.sa
.sa_flags
& SA_EXPOSE_TAGBITS
))
2863 hide_si_addr_tag_bits(ksig
);
2865 return ksig
->sig
> 0;
2869 * signal_delivered -
2870 * @ksig: kernel signal struct
2871 * @stepping: nonzero if debugger single-step or block-step in use
2873 * This function should be called when a signal has successfully been
2874 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2875 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2876 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2878 static void signal_delivered(struct ksignal
*ksig
, int stepping
)
2882 /* A signal was successfully delivered, and the
2883 saved sigmask was stored on the signal frame,
2884 and will be restored by sigreturn. So we can
2885 simply clear the restore sigmask flag. */
2886 clear_restore_sigmask();
2888 sigorsets(&blocked
, ¤t
->blocked
, &ksig
->ka
.sa
.sa_mask
);
2889 if (!(ksig
->ka
.sa
.sa_flags
& SA_NODEFER
))
2890 sigaddset(&blocked
, ksig
->sig
);
2891 set_current_blocked(&blocked
);
2892 if (current
->sas_ss_flags
& SS_AUTODISARM
)
2893 sas_ss_reset(current
);
2894 tracehook_signal_handler(stepping
);
2897 void signal_setup_done(int failed
, struct ksignal
*ksig
, int stepping
)
2900 force_sigsegv(ksig
->sig
);
2902 signal_delivered(ksig
, stepping
);
2906 * It could be that complete_signal() picked us to notify about the
2907 * group-wide signal. Other threads should be notified now to take
2908 * the shared signals in @which since we will not.
2910 static void retarget_shared_pending(struct task_struct
*tsk
, sigset_t
*which
)
2913 struct task_struct
*t
;
2915 sigandsets(&retarget
, &tsk
->signal
->shared_pending
.signal
, which
);
2916 if (sigisemptyset(&retarget
))
2920 while_each_thread(tsk
, t
) {
2921 if (t
->flags
& PF_EXITING
)
2924 if (!has_pending_signals(&retarget
, &t
->blocked
))
2926 /* Remove the signals this thread can handle. */
2927 sigandsets(&retarget
, &retarget
, &t
->blocked
);
2929 if (!task_sigpending(t
))
2930 signal_wake_up(t
, 0);
2932 if (sigisemptyset(&retarget
))
2937 void exit_signals(struct task_struct
*tsk
)
2943 * @tsk is about to have PF_EXITING set - lock out users which
2944 * expect stable threadgroup.
2946 cgroup_threadgroup_change_begin(tsk
);
2948 if (thread_group_empty(tsk
) || signal_group_exit(tsk
->signal
)) {
2949 tsk
->flags
|= PF_EXITING
;
2950 cgroup_threadgroup_change_end(tsk
);
2954 spin_lock_irq(&tsk
->sighand
->siglock
);
2956 * From now this task is not visible for group-wide signals,
2957 * see wants_signal(), do_signal_stop().
2959 tsk
->flags
|= PF_EXITING
;
2961 cgroup_threadgroup_change_end(tsk
);
2963 if (!task_sigpending(tsk
))
2966 unblocked
= tsk
->blocked
;
2967 signotset(&unblocked
);
2968 retarget_shared_pending(tsk
, &unblocked
);
2970 if (unlikely(tsk
->jobctl
& JOBCTL_STOP_PENDING
) &&
2971 task_participate_group_stop(tsk
))
2972 group_stop
= CLD_STOPPED
;
2974 spin_unlock_irq(&tsk
->sighand
->siglock
);
2977 * If group stop has completed, deliver the notification. This
2978 * should always go to the real parent of the group leader.
2980 if (unlikely(group_stop
)) {
2981 read_lock(&tasklist_lock
);
2982 do_notify_parent_cldstop(tsk
, false, group_stop
);
2983 read_unlock(&tasklist_lock
);
2988 * System call entry points.
2992 * sys_restart_syscall - restart a system call
2994 SYSCALL_DEFINE0(restart_syscall
)
2996 struct restart_block
*restart
= ¤t
->restart_block
;
2997 return restart
->fn(restart
);
3000 long do_no_restart_syscall(struct restart_block
*param
)
3005 static void __set_task_blocked(struct task_struct
*tsk
, const sigset_t
*newset
)
3007 if (task_sigpending(tsk
) && !thread_group_empty(tsk
)) {
3008 sigset_t newblocked
;
3009 /* A set of now blocked but previously unblocked signals. */
3010 sigandnsets(&newblocked
, newset
, ¤t
->blocked
);
3011 retarget_shared_pending(tsk
, &newblocked
);
3013 tsk
->blocked
= *newset
;
3014 recalc_sigpending();
3018 * set_current_blocked - change current->blocked mask
3021 * It is wrong to change ->blocked directly, this helper should be used
3022 * to ensure the process can't miss a shared signal we are going to block.
3024 void set_current_blocked(sigset_t
*newset
)
3026 sigdelsetmask(newset
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
3027 __set_current_blocked(newset
);
3030 void __set_current_blocked(const sigset_t
*newset
)
3032 struct task_struct
*tsk
= current
;
3035 * In case the signal mask hasn't changed, there is nothing we need
3036 * to do. The current->blocked shouldn't be modified by other task.
3038 if (sigequalsets(&tsk
->blocked
, newset
))
3041 spin_lock_irq(&tsk
->sighand
->siglock
);
3042 __set_task_blocked(tsk
, newset
);
3043 spin_unlock_irq(&tsk
->sighand
->siglock
);
3047 * This is also useful for kernel threads that want to temporarily
3048 * (or permanently) block certain signals.
3050 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
3051 * interface happily blocks "unblockable" signals like SIGKILL
3054 int sigprocmask(int how
, sigset_t
*set
, sigset_t
*oldset
)
3056 struct task_struct
*tsk
= current
;
3059 /* Lockless, only current can change ->blocked, never from irq */
3061 *oldset
= tsk
->blocked
;
3065 sigorsets(&newset
, &tsk
->blocked
, set
);
3068 sigandnsets(&newset
, &tsk
->blocked
, set
);
3077 __set_current_blocked(&newset
);
3080 EXPORT_SYMBOL(sigprocmask
);
3083 * The api helps set app-provided sigmasks.
3085 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
3086 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
3088 * Note that it does set_restore_sigmask() in advance, so it must be always
3089 * paired with restore_saved_sigmask_unless() before return from syscall.
3091 int set_user_sigmask(const sigset_t __user
*umask
, size_t sigsetsize
)
3097 if (sigsetsize
!= sizeof(sigset_t
))
3099 if (copy_from_user(&kmask
, umask
, sizeof(sigset_t
)))
3102 set_restore_sigmask();
3103 current
->saved_sigmask
= current
->blocked
;
3104 set_current_blocked(&kmask
);
3109 #ifdef CONFIG_COMPAT
3110 int set_compat_user_sigmask(const compat_sigset_t __user
*umask
,
3117 if (sigsetsize
!= sizeof(compat_sigset_t
))
3119 if (get_compat_sigset(&kmask
, umask
))
3122 set_restore_sigmask();
3123 current
->saved_sigmask
= current
->blocked
;
3124 set_current_blocked(&kmask
);
3131 * sys_rt_sigprocmask - change the list of currently blocked signals
3132 * @how: whether to add, remove, or set signals
3133 * @nset: stores pending signals
3134 * @oset: previous value of signal mask if non-null
3135 * @sigsetsize: size of sigset_t type
3137 SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, sigset_t __user
*, nset
,
3138 sigset_t __user
*, oset
, size_t, sigsetsize
)
3140 sigset_t old_set
, new_set
;
3143 /* XXX: Don't preclude handling different sized sigset_t's. */
3144 if (sigsetsize
!= sizeof(sigset_t
))
3147 old_set
= current
->blocked
;
3150 if (copy_from_user(&new_set
, nset
, sizeof(sigset_t
)))
3152 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
3154 error
= sigprocmask(how
, &new_set
, NULL
);
3160 if (copy_to_user(oset
, &old_set
, sizeof(sigset_t
)))
3167 #ifdef CONFIG_COMPAT
3168 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, compat_sigset_t __user
*, nset
,
3169 compat_sigset_t __user
*, oset
, compat_size_t
, sigsetsize
)
3171 sigset_t old_set
= current
->blocked
;
3173 /* XXX: Don't preclude handling different sized sigset_t's. */
3174 if (sigsetsize
!= sizeof(sigset_t
))
3180 if (get_compat_sigset(&new_set
, nset
))
3182 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
3184 error
= sigprocmask(how
, &new_set
, NULL
);
3188 return oset
? put_compat_sigset(oset
, &old_set
, sizeof(*oset
)) : 0;
3192 static void do_sigpending(sigset_t
*set
)
3194 spin_lock_irq(¤t
->sighand
->siglock
);
3195 sigorsets(set
, ¤t
->pending
.signal
,
3196 ¤t
->signal
->shared_pending
.signal
);
3197 spin_unlock_irq(¤t
->sighand
->siglock
);
3199 /* Outside the lock because only this thread touches it. */
3200 sigandsets(set
, ¤t
->blocked
, set
);
3204 * sys_rt_sigpending - examine a pending signal that has been raised
3206 * @uset: stores pending signals
3207 * @sigsetsize: size of sigset_t type or larger
3209 SYSCALL_DEFINE2(rt_sigpending
, sigset_t __user
*, uset
, size_t, sigsetsize
)
3213 if (sigsetsize
> sizeof(*uset
))
3216 do_sigpending(&set
);
3218 if (copy_to_user(uset
, &set
, sigsetsize
))
3224 #ifdef CONFIG_COMPAT
3225 COMPAT_SYSCALL_DEFINE2(rt_sigpending
, compat_sigset_t __user
*, uset
,
3226 compat_size_t
, sigsetsize
)
3230 if (sigsetsize
> sizeof(*uset
))
3233 do_sigpending(&set
);
3235 return put_compat_sigset(uset
, &set
, sigsetsize
);
3239 static const struct {
3240 unsigned char limit
, layout
;
3242 [SIGILL
] = { NSIGILL
, SIL_FAULT
},
3243 [SIGFPE
] = { NSIGFPE
, SIL_FAULT
},
3244 [SIGSEGV
] = { NSIGSEGV
, SIL_FAULT
},
3245 [SIGBUS
] = { NSIGBUS
, SIL_FAULT
},
3246 [SIGTRAP
] = { NSIGTRAP
, SIL_FAULT
},
3248 [SIGEMT
] = { NSIGEMT
, SIL_FAULT
},
3250 [SIGCHLD
] = { NSIGCHLD
, SIL_CHLD
},
3251 [SIGPOLL
] = { NSIGPOLL
, SIL_POLL
},
3252 [SIGSYS
] = { NSIGSYS
, SIL_SYS
},
3255 static bool known_siginfo_layout(unsigned sig
, int si_code
)
3257 if (si_code
== SI_KERNEL
)
3259 else if ((si_code
> SI_USER
)) {
3260 if (sig_specific_sicodes(sig
)) {
3261 if (si_code
<= sig_sicodes
[sig
].limit
)
3264 else if (si_code
<= NSIGPOLL
)
3267 else if (si_code
>= SI_DETHREAD
)
3269 else if (si_code
== SI_ASYNCNL
)
3274 enum siginfo_layout
siginfo_layout(unsigned sig
, int si_code
)
3276 enum siginfo_layout layout
= SIL_KILL
;
3277 if ((si_code
> SI_USER
) && (si_code
< SI_KERNEL
)) {
3278 if ((sig
< ARRAY_SIZE(sig_sicodes
)) &&
3279 (si_code
<= sig_sicodes
[sig
].limit
)) {
3280 layout
= sig_sicodes
[sig
].layout
;
3281 /* Handle the exceptions */
3282 if ((sig
== SIGBUS
) &&
3283 (si_code
>= BUS_MCEERR_AR
) && (si_code
<= BUS_MCEERR_AO
))
3284 layout
= SIL_FAULT_MCEERR
;
3285 else if ((sig
== SIGSEGV
) && (si_code
== SEGV_BNDERR
))
3286 layout
= SIL_FAULT_BNDERR
;
3288 else if ((sig
== SIGSEGV
) && (si_code
== SEGV_PKUERR
))
3289 layout
= SIL_FAULT_PKUERR
;
3291 else if ((sig
== SIGTRAP
) && (si_code
== TRAP_PERF
))
3292 layout
= SIL_FAULT_PERF_EVENT
;
3293 else if (IS_ENABLED(CONFIG_SPARC
) &&
3294 (sig
== SIGILL
) && (si_code
== ILL_ILLTRP
))
3295 layout
= SIL_FAULT_TRAPNO
;
3296 else if (IS_ENABLED(CONFIG_ALPHA
) &&
3298 ((sig
== SIGTRAP
) && (si_code
== TRAP_UNK
))))
3299 layout
= SIL_FAULT_TRAPNO
;
3301 else if (si_code
<= NSIGPOLL
)
3304 if (si_code
== SI_TIMER
)
3306 else if (si_code
== SI_SIGIO
)
3308 else if (si_code
< 0)
3314 static inline char __user
*si_expansion(const siginfo_t __user
*info
)
3316 return ((char __user
*)info
) + sizeof(struct kernel_siginfo
);
3319 int copy_siginfo_to_user(siginfo_t __user
*to
, const kernel_siginfo_t
*from
)
3321 char __user
*expansion
= si_expansion(to
);
3322 if (copy_to_user(to
, from
, sizeof(struct kernel_siginfo
)))
3324 if (clear_user(expansion
, SI_EXPANSION_SIZE
))
3329 static int post_copy_siginfo_from_user(kernel_siginfo_t
*info
,
3330 const siginfo_t __user
*from
)
3332 if (unlikely(!known_siginfo_layout(info
->si_signo
, info
->si_code
))) {
3333 char __user
*expansion
= si_expansion(from
);
3334 char buf
[SI_EXPANSION_SIZE
];
3337 * An unknown si_code might need more than
3338 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3339 * extra bytes are 0. This guarantees copy_siginfo_to_user
3340 * will return this data to userspace exactly.
3342 if (copy_from_user(&buf
, expansion
, SI_EXPANSION_SIZE
))
3344 for (i
= 0; i
< SI_EXPANSION_SIZE
; i
++) {
3352 static int __copy_siginfo_from_user(int signo
, kernel_siginfo_t
*to
,
3353 const siginfo_t __user
*from
)
3355 if (copy_from_user(to
, from
, sizeof(struct kernel_siginfo
)))
3357 to
->si_signo
= signo
;
3358 return post_copy_siginfo_from_user(to
, from
);
3361 int copy_siginfo_from_user(kernel_siginfo_t
*to
, const siginfo_t __user
*from
)
3363 if (copy_from_user(to
, from
, sizeof(struct kernel_siginfo
)))
3365 return post_copy_siginfo_from_user(to
, from
);
3368 #ifdef CONFIG_COMPAT
3370 * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
3371 * @to: compat siginfo destination
3372 * @from: kernel siginfo source
3374 * Note: This function does not work properly for the SIGCHLD on x32, but
3375 * fortunately it doesn't have to. The only valid callers for this function are
3376 * copy_siginfo_to_user32, which is overriden for x32 and the coredump code.
3377 * The latter does not care because SIGCHLD will never cause a coredump.
3379 void copy_siginfo_to_external32(struct compat_siginfo
*to
,
3380 const struct kernel_siginfo
*from
)
3382 memset(to
, 0, sizeof(*to
));
3384 to
->si_signo
= from
->si_signo
;
3385 to
->si_errno
= from
->si_errno
;
3386 to
->si_code
= from
->si_code
;
3387 switch(siginfo_layout(from
->si_signo
, from
->si_code
)) {
3389 to
->si_pid
= from
->si_pid
;
3390 to
->si_uid
= from
->si_uid
;
3393 to
->si_tid
= from
->si_tid
;
3394 to
->si_overrun
= from
->si_overrun
;
3395 to
->si_int
= from
->si_int
;
3398 to
->si_band
= from
->si_band
;
3399 to
->si_fd
= from
->si_fd
;
3402 to
->si_addr
= ptr_to_compat(from
->si_addr
);
3404 case SIL_FAULT_TRAPNO
:
3405 to
->si_addr
= ptr_to_compat(from
->si_addr
);
3406 to
->si_trapno
= from
->si_trapno
;
3408 case SIL_FAULT_MCEERR
:
3409 to
->si_addr
= ptr_to_compat(from
->si_addr
);
3410 to
->si_addr_lsb
= from
->si_addr_lsb
;
3412 case SIL_FAULT_BNDERR
:
3413 to
->si_addr
= ptr_to_compat(from
->si_addr
);
3414 to
->si_lower
= ptr_to_compat(from
->si_lower
);
3415 to
->si_upper
= ptr_to_compat(from
->si_upper
);
3417 case SIL_FAULT_PKUERR
:
3418 to
->si_addr
= ptr_to_compat(from
->si_addr
);
3419 to
->si_pkey
= from
->si_pkey
;
3421 case SIL_FAULT_PERF_EVENT
:
3422 to
->si_addr
= ptr_to_compat(from
->si_addr
);
3423 to
->si_perf_data
= from
->si_perf_data
;
3424 to
->si_perf_type
= from
->si_perf_type
;
3427 to
->si_pid
= from
->si_pid
;
3428 to
->si_uid
= from
->si_uid
;
3429 to
->si_status
= from
->si_status
;
3430 to
->si_utime
= from
->si_utime
;
3431 to
->si_stime
= from
->si_stime
;
3434 to
->si_pid
= from
->si_pid
;
3435 to
->si_uid
= from
->si_uid
;
3436 to
->si_int
= from
->si_int
;
3439 to
->si_call_addr
= ptr_to_compat(from
->si_call_addr
);
3440 to
->si_syscall
= from
->si_syscall
;
3441 to
->si_arch
= from
->si_arch
;
3446 int __copy_siginfo_to_user32(struct compat_siginfo __user
*to
,
3447 const struct kernel_siginfo
*from
)
3449 struct compat_siginfo
new;
3451 copy_siginfo_to_external32(&new, from
);
3452 if (copy_to_user(to
, &new, sizeof(struct compat_siginfo
)))
3457 static int post_copy_siginfo_from_user32(kernel_siginfo_t
*to
,
3458 const struct compat_siginfo
*from
)
3461 to
->si_signo
= from
->si_signo
;
3462 to
->si_errno
= from
->si_errno
;
3463 to
->si_code
= from
->si_code
;
3464 switch(siginfo_layout(from
->si_signo
, from
->si_code
)) {
3466 to
->si_pid
= from
->si_pid
;
3467 to
->si_uid
= from
->si_uid
;
3470 to
->si_tid
= from
->si_tid
;
3471 to
->si_overrun
= from
->si_overrun
;
3472 to
->si_int
= from
->si_int
;
3475 to
->si_band
= from
->si_band
;
3476 to
->si_fd
= from
->si_fd
;
3479 to
->si_addr
= compat_ptr(from
->si_addr
);
3481 case SIL_FAULT_TRAPNO
:
3482 to
->si_addr
= compat_ptr(from
->si_addr
);
3483 to
->si_trapno
= from
->si_trapno
;
3485 case SIL_FAULT_MCEERR
:
3486 to
->si_addr
= compat_ptr(from
->si_addr
);
3487 to
->si_addr_lsb
= from
->si_addr_lsb
;
3489 case SIL_FAULT_BNDERR
:
3490 to
->si_addr
= compat_ptr(from
->si_addr
);
3491 to
->si_lower
= compat_ptr(from
->si_lower
);
3492 to
->si_upper
= compat_ptr(from
->si_upper
);
3494 case SIL_FAULT_PKUERR
:
3495 to
->si_addr
= compat_ptr(from
->si_addr
);
3496 to
->si_pkey
= from
->si_pkey
;
3498 case SIL_FAULT_PERF_EVENT
:
3499 to
->si_addr
= compat_ptr(from
->si_addr
);
3500 to
->si_perf_data
= from
->si_perf_data
;
3501 to
->si_perf_type
= from
->si_perf_type
;
3504 to
->si_pid
= from
->si_pid
;
3505 to
->si_uid
= from
->si_uid
;
3506 to
->si_status
= from
->si_status
;
3507 #ifdef CONFIG_X86_X32_ABI
3508 if (in_x32_syscall()) {
3509 to
->si_utime
= from
->_sifields
._sigchld_x32
._utime
;
3510 to
->si_stime
= from
->_sifields
._sigchld_x32
._stime
;
3514 to
->si_utime
= from
->si_utime
;
3515 to
->si_stime
= from
->si_stime
;
3519 to
->si_pid
= from
->si_pid
;
3520 to
->si_uid
= from
->si_uid
;
3521 to
->si_int
= from
->si_int
;
3524 to
->si_call_addr
= compat_ptr(from
->si_call_addr
);
3525 to
->si_syscall
= from
->si_syscall
;
3526 to
->si_arch
= from
->si_arch
;
3532 static int __copy_siginfo_from_user32(int signo
, struct kernel_siginfo
*to
,
3533 const struct compat_siginfo __user
*ufrom
)
3535 struct compat_siginfo from
;
3537 if (copy_from_user(&from
, ufrom
, sizeof(struct compat_siginfo
)))
3540 from
.si_signo
= signo
;
3541 return post_copy_siginfo_from_user32(to
, &from
);
3544 int copy_siginfo_from_user32(struct kernel_siginfo
*to
,
3545 const struct compat_siginfo __user
*ufrom
)
3547 struct compat_siginfo from
;
3549 if (copy_from_user(&from
, ufrom
, sizeof(struct compat_siginfo
)))
3552 return post_copy_siginfo_from_user32(to
, &from
);
3554 #endif /* CONFIG_COMPAT */
3557 * do_sigtimedwait - wait for queued signals specified in @which
3558 * @which: queued signals to wait for
3559 * @info: if non-null, the signal's siginfo is returned here
3560 * @ts: upper bound on process time suspension
3562 static int do_sigtimedwait(const sigset_t
*which
, kernel_siginfo_t
*info
,
3563 const struct timespec64
*ts
)
3565 ktime_t
*to
= NULL
, timeout
= KTIME_MAX
;
3566 struct task_struct
*tsk
= current
;
3567 sigset_t mask
= *which
;
3571 if (!timespec64_valid(ts
))
3573 timeout
= timespec64_to_ktime(*ts
);
3578 * Invert the set of allowed signals to get those we want to block.
3580 sigdelsetmask(&mask
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
3583 spin_lock_irq(&tsk
->sighand
->siglock
);
3584 sig
= dequeue_signal(tsk
, &mask
, info
);
3585 if (!sig
&& timeout
) {
3587 * None ready, temporarily unblock those we're interested
3588 * while we are sleeping in so that we'll be awakened when
3589 * they arrive. Unblocking is always fine, we can avoid
3590 * set_current_blocked().
3592 tsk
->real_blocked
= tsk
->blocked
;
3593 sigandsets(&tsk
->blocked
, &tsk
->blocked
, &mask
);
3594 recalc_sigpending();
3595 spin_unlock_irq(&tsk
->sighand
->siglock
);
3597 __set_current_state(TASK_INTERRUPTIBLE
);
3598 ret
= freezable_schedule_hrtimeout_range(to
, tsk
->timer_slack_ns
,
3600 spin_lock_irq(&tsk
->sighand
->siglock
);
3601 __set_task_blocked(tsk
, &tsk
->real_blocked
);
3602 sigemptyset(&tsk
->real_blocked
);
3603 sig
= dequeue_signal(tsk
, &mask
, info
);
3605 spin_unlock_irq(&tsk
->sighand
->siglock
);
3609 return ret
? -EINTR
: -EAGAIN
;
3613 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3615 * @uthese: queued signals to wait for
3616 * @uinfo: if non-null, the signal's siginfo is returned here
3617 * @uts: upper bound on process time suspension
3618 * @sigsetsize: size of sigset_t type
3620 SYSCALL_DEFINE4(rt_sigtimedwait
, const sigset_t __user
*, uthese
,
3621 siginfo_t __user
*, uinfo
,
3622 const struct __kernel_timespec __user
*, uts
,
3626 struct timespec64 ts
;
3627 kernel_siginfo_t info
;
3630 /* XXX: Don't preclude handling different sized sigset_t's. */
3631 if (sigsetsize
!= sizeof(sigset_t
))
3634 if (copy_from_user(&these
, uthese
, sizeof(these
)))
3638 if (get_timespec64(&ts
, uts
))
3642 ret
= do_sigtimedwait(&these
, &info
, uts
? &ts
: NULL
);
3644 if (ret
> 0 && uinfo
) {
3645 if (copy_siginfo_to_user(uinfo
, &info
))
3652 #ifdef CONFIG_COMPAT_32BIT_TIME
3653 SYSCALL_DEFINE4(rt_sigtimedwait_time32
, const sigset_t __user
*, uthese
,
3654 siginfo_t __user
*, uinfo
,
3655 const struct old_timespec32 __user
*, uts
,
3659 struct timespec64 ts
;
3660 kernel_siginfo_t info
;
3663 if (sigsetsize
!= sizeof(sigset_t
))
3666 if (copy_from_user(&these
, uthese
, sizeof(these
)))
3670 if (get_old_timespec32(&ts
, uts
))
3674 ret
= do_sigtimedwait(&these
, &info
, uts
? &ts
: NULL
);
3676 if (ret
> 0 && uinfo
) {
3677 if (copy_siginfo_to_user(uinfo
, &info
))
3685 #ifdef CONFIG_COMPAT
3686 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64
, compat_sigset_t __user
*, uthese
,
3687 struct compat_siginfo __user
*, uinfo
,
3688 struct __kernel_timespec __user
*, uts
, compat_size_t
, sigsetsize
)
3691 struct timespec64 t
;
3692 kernel_siginfo_t info
;
3695 if (sigsetsize
!= sizeof(sigset_t
))
3698 if (get_compat_sigset(&s
, uthese
))
3702 if (get_timespec64(&t
, uts
))
3706 ret
= do_sigtimedwait(&s
, &info
, uts
? &t
: NULL
);
3708 if (ret
> 0 && uinfo
) {
3709 if (copy_siginfo_to_user32(uinfo
, &info
))
3716 #ifdef CONFIG_COMPAT_32BIT_TIME
3717 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32
, compat_sigset_t __user
*, uthese
,
3718 struct compat_siginfo __user
*, uinfo
,
3719 struct old_timespec32 __user
*, uts
, compat_size_t
, sigsetsize
)
3722 struct timespec64 t
;
3723 kernel_siginfo_t info
;
3726 if (sigsetsize
!= sizeof(sigset_t
))
3729 if (get_compat_sigset(&s
, uthese
))
3733 if (get_old_timespec32(&t
, uts
))
3737 ret
= do_sigtimedwait(&s
, &info
, uts
? &t
: NULL
);
3739 if (ret
> 0 && uinfo
) {
3740 if (copy_siginfo_to_user32(uinfo
, &info
))
3749 static inline void prepare_kill_siginfo(int sig
, struct kernel_siginfo
*info
)
3751 clear_siginfo(info
);
3752 info
->si_signo
= sig
;
3754 info
->si_code
= SI_USER
;
3755 info
->si_pid
= task_tgid_vnr(current
);
3756 info
->si_uid
= from_kuid_munged(current_user_ns(), current_uid());
3760 * sys_kill - send a signal to a process
3761 * @pid: the PID of the process
3762 * @sig: signal to be sent
3764 SYSCALL_DEFINE2(kill
, pid_t
, pid
, int, sig
)
3766 struct kernel_siginfo info
;
3768 prepare_kill_siginfo(sig
, &info
);
3770 return kill_something_info(sig
, &info
, pid
);
3774 * Verify that the signaler and signalee either are in the same pid namespace
3775 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3778 static bool access_pidfd_pidns(struct pid
*pid
)
3780 struct pid_namespace
*active
= task_active_pid_ns(current
);
3781 struct pid_namespace
*p
= ns_of_pid(pid
);
3794 static int copy_siginfo_from_user_any(kernel_siginfo_t
*kinfo
,
3795 siginfo_t __user
*info
)
3797 #ifdef CONFIG_COMPAT
3799 * Avoid hooking up compat syscalls and instead handle necessary
3800 * conversions here. Note, this is a stop-gap measure and should not be
3801 * considered a generic solution.
3803 if (in_compat_syscall())
3804 return copy_siginfo_from_user32(
3805 kinfo
, (struct compat_siginfo __user
*)info
);
3807 return copy_siginfo_from_user(kinfo
, info
);
3810 static struct pid
*pidfd_to_pid(const struct file
*file
)
3814 pid
= pidfd_pid(file
);
3818 return tgid_pidfd_to_pid(file
);
3822 * sys_pidfd_send_signal - Signal a process through a pidfd
3823 * @pidfd: file descriptor of the process
3824 * @sig: signal to send
3825 * @info: signal info
3826 * @flags: future flags
3828 * The syscall currently only signals via PIDTYPE_PID which covers
3829 * kill(<positive-pid>, <signal>. It does not signal threads or process
3831 * In order to extend the syscall to threads and process groups the @flags
3832 * argument should be used. In essence, the @flags argument will determine
3833 * what is signaled and not the file descriptor itself. Put in other words,
3834 * grouping is a property of the flags argument not a property of the file
3837 * Return: 0 on success, negative errno on failure
3839 SYSCALL_DEFINE4(pidfd_send_signal
, int, pidfd
, int, sig
,
3840 siginfo_t __user
*, info
, unsigned int, flags
)
3845 kernel_siginfo_t kinfo
;
3847 /* Enforce flags be set to 0 until we add an extension. */
3855 /* Is this a pidfd? */
3856 pid
= pidfd_to_pid(f
.file
);
3863 if (!access_pidfd_pidns(pid
))
3867 ret
= copy_siginfo_from_user_any(&kinfo
, info
);
3872 if (unlikely(sig
!= kinfo
.si_signo
))
3875 /* Only allow sending arbitrary signals to yourself. */
3877 if ((task_pid(current
) != pid
) &&
3878 (kinfo
.si_code
>= 0 || kinfo
.si_code
== SI_TKILL
))
3881 prepare_kill_siginfo(sig
, &kinfo
);
3884 ret
= kill_pid_info(sig
, &kinfo
, pid
);
3892 do_send_specific(pid_t tgid
, pid_t pid
, int sig
, struct kernel_siginfo
*info
)
3894 struct task_struct
*p
;
3898 p
= find_task_by_vpid(pid
);
3899 if (p
&& (tgid
<= 0 || task_tgid_vnr(p
) == tgid
)) {
3900 error
= check_kill_permission(sig
, info
, p
);
3902 * The null signal is a permissions and process existence
3903 * probe. No signal is actually delivered.
3905 if (!error
&& sig
) {
3906 error
= do_send_sig_info(sig
, info
, p
, PIDTYPE_PID
);
3908 * If lock_task_sighand() failed we pretend the task
3909 * dies after receiving the signal. The window is tiny,
3910 * and the signal is private anyway.
3912 if (unlikely(error
== -ESRCH
))
3921 static int do_tkill(pid_t tgid
, pid_t pid
, int sig
)
3923 struct kernel_siginfo info
;
3925 clear_siginfo(&info
);
3926 info
.si_signo
= sig
;
3928 info
.si_code
= SI_TKILL
;
3929 info
.si_pid
= task_tgid_vnr(current
);
3930 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
3932 return do_send_specific(tgid
, pid
, sig
, &info
);
3936 * sys_tgkill - send signal to one specific thread
3937 * @tgid: the thread group ID of the thread
3938 * @pid: the PID of the thread
3939 * @sig: signal to be sent
3941 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3942 * exists but it's not belonging to the target process anymore. This
3943 * method solves the problem of threads exiting and PIDs getting reused.
3945 SYSCALL_DEFINE3(tgkill
, pid_t
, tgid
, pid_t
, pid
, int, sig
)
3947 /* This is only valid for single tasks */
3948 if (pid
<= 0 || tgid
<= 0)
3951 return do_tkill(tgid
, pid
, sig
);
3955 * sys_tkill - send signal to one specific task
3956 * @pid: the PID of the task
3957 * @sig: signal to be sent
3959 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3961 SYSCALL_DEFINE2(tkill
, pid_t
, pid
, int, sig
)
3963 /* This is only valid for single tasks */
3967 return do_tkill(0, pid
, sig
);
3970 static int do_rt_sigqueueinfo(pid_t pid
, int sig
, kernel_siginfo_t
*info
)
3972 /* Not even root can pretend to send signals from the kernel.
3973 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3975 if ((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
) &&
3976 (task_pid_vnr(current
) != pid
))
3979 /* POSIX.1b doesn't mention process groups. */
3980 return kill_proc_info(sig
, info
, pid
);
3984 * sys_rt_sigqueueinfo - send signal information to a signal
3985 * @pid: the PID of the thread
3986 * @sig: signal to be sent
3987 * @uinfo: signal info to be sent
3989 SYSCALL_DEFINE3(rt_sigqueueinfo
, pid_t
, pid
, int, sig
,
3990 siginfo_t __user
*, uinfo
)
3992 kernel_siginfo_t info
;
3993 int ret
= __copy_siginfo_from_user(sig
, &info
, uinfo
);
3996 return do_rt_sigqueueinfo(pid
, sig
, &info
);
3999 #ifdef CONFIG_COMPAT
4000 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo
,
4003 struct compat_siginfo __user
*, uinfo
)
4005 kernel_siginfo_t info
;
4006 int ret
= __copy_siginfo_from_user32(sig
, &info
, uinfo
);
4009 return do_rt_sigqueueinfo(pid
, sig
, &info
);
4013 static int do_rt_tgsigqueueinfo(pid_t tgid
, pid_t pid
, int sig
, kernel_siginfo_t
*info
)
4015 /* This is only valid for single tasks */
4016 if (pid
<= 0 || tgid
<= 0)
4019 /* Not even root can pretend to send signals from the kernel.
4020 * Nor can they impersonate a kill()/tgkill(), which adds source info.
4022 if ((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
) &&
4023 (task_pid_vnr(current
) != pid
))
4026 return do_send_specific(tgid
, pid
, sig
, info
);
4029 SYSCALL_DEFINE4(rt_tgsigqueueinfo
, pid_t
, tgid
, pid_t
, pid
, int, sig
,
4030 siginfo_t __user
*, uinfo
)
4032 kernel_siginfo_t info
;
4033 int ret
= __copy_siginfo_from_user(sig
, &info
, uinfo
);
4036 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
4039 #ifdef CONFIG_COMPAT
4040 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo
,
4044 struct compat_siginfo __user
*, uinfo
)
4046 kernel_siginfo_t info
;
4047 int ret
= __copy_siginfo_from_user32(sig
, &info
, uinfo
);
4050 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
4055 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
4057 void kernel_sigaction(int sig
, __sighandler_t action
)
4059 spin_lock_irq(¤t
->sighand
->siglock
);
4060 current
->sighand
->action
[sig
- 1].sa
.sa_handler
= action
;
4061 if (action
== SIG_IGN
) {
4065 sigaddset(&mask
, sig
);
4067 flush_sigqueue_mask(&mask
, ¤t
->signal
->shared_pending
);
4068 flush_sigqueue_mask(&mask
, ¤t
->pending
);
4069 recalc_sigpending();
4071 spin_unlock_irq(¤t
->sighand
->siglock
);
4073 EXPORT_SYMBOL(kernel_sigaction
);
4075 void __weak
sigaction_compat_abi(struct k_sigaction
*act
,
4076 struct k_sigaction
*oact
)
4080 int do_sigaction(int sig
, struct k_sigaction
*act
, struct k_sigaction
*oact
)
4082 struct task_struct
*p
= current
, *t
;
4083 struct k_sigaction
*k
;
4086 if (!valid_signal(sig
) || sig
< 1 || (act
&& sig_kernel_only(sig
)))
4089 k
= &p
->sighand
->action
[sig
-1];
4091 spin_lock_irq(&p
->sighand
->siglock
);
4092 if (k
->sa
.sa_flags
& SA_IMMUTABLE
) {
4093 spin_unlock_irq(&p
->sighand
->siglock
);
4100 * Make sure that we never accidentally claim to support SA_UNSUPPORTED,
4101 * e.g. by having an architecture use the bit in their uapi.
4103 BUILD_BUG_ON(UAPI_SA_FLAGS
& SA_UNSUPPORTED
);
4106 * Clear unknown flag bits in order to allow userspace to detect missing
4107 * support for flag bits and to allow the kernel to use non-uapi bits
4111 act
->sa
.sa_flags
&= UAPI_SA_FLAGS
;
4113 oact
->sa
.sa_flags
&= UAPI_SA_FLAGS
;
4115 sigaction_compat_abi(act
, oact
);
4118 sigdelsetmask(&act
->sa
.sa_mask
,
4119 sigmask(SIGKILL
) | sigmask(SIGSTOP
));
4123 * "Setting a signal action to SIG_IGN for a signal that is
4124 * pending shall cause the pending signal to be discarded,
4125 * whether or not it is blocked."
4127 * "Setting a signal action to SIG_DFL for a signal that is
4128 * pending and whose default action is to ignore the signal
4129 * (for example, SIGCHLD), shall cause the pending signal to
4130 * be discarded, whether or not it is blocked"
4132 if (sig_handler_ignored(sig_handler(p
, sig
), sig
)) {
4134 sigaddset(&mask
, sig
);
4135 flush_sigqueue_mask(&mask
, &p
->signal
->shared_pending
);
4136 for_each_thread(p
, t
)
4137 flush_sigqueue_mask(&mask
, &t
->pending
);
4141 spin_unlock_irq(&p
->sighand
->siglock
);
4146 do_sigaltstack (const stack_t
*ss
, stack_t
*oss
, unsigned long sp
,
4149 struct task_struct
*t
= current
;
4152 memset(oss
, 0, sizeof(stack_t
));
4153 oss
->ss_sp
= (void __user
*) t
->sas_ss_sp
;
4154 oss
->ss_size
= t
->sas_ss_size
;
4155 oss
->ss_flags
= sas_ss_flags(sp
) |
4156 (current
->sas_ss_flags
& SS_FLAG_BITS
);
4160 void __user
*ss_sp
= ss
->ss_sp
;
4161 size_t ss_size
= ss
->ss_size
;
4162 unsigned ss_flags
= ss
->ss_flags
;
4165 if (unlikely(on_sig_stack(sp
)))
4168 ss_mode
= ss_flags
& ~SS_FLAG_BITS
;
4169 if (unlikely(ss_mode
!= SS_DISABLE
&& ss_mode
!= SS_ONSTACK
&&
4173 if (ss_mode
== SS_DISABLE
) {
4177 if (unlikely(ss_size
< min_ss_size
))
4181 t
->sas_ss_sp
= (unsigned long) ss_sp
;
4182 t
->sas_ss_size
= ss_size
;
4183 t
->sas_ss_flags
= ss_flags
;
4188 SYSCALL_DEFINE2(sigaltstack
,const stack_t __user
*,uss
, stack_t __user
*,uoss
)
4192 if (uss
&& copy_from_user(&new, uss
, sizeof(stack_t
)))
4194 err
= do_sigaltstack(uss
? &new : NULL
, uoss
? &old
: NULL
,
4195 current_user_stack_pointer(),
4197 if (!err
&& uoss
&& copy_to_user(uoss
, &old
, sizeof(stack_t
)))
4202 int restore_altstack(const stack_t __user
*uss
)
4205 if (copy_from_user(&new, uss
, sizeof(stack_t
)))
4207 (void)do_sigaltstack(&new, NULL
, current_user_stack_pointer(),
4209 /* squash all but EFAULT for now */
4213 int __save_altstack(stack_t __user
*uss
, unsigned long sp
)
4215 struct task_struct
*t
= current
;
4216 int err
= __put_user((void __user
*)t
->sas_ss_sp
, &uss
->ss_sp
) |
4217 __put_user(t
->sas_ss_flags
, &uss
->ss_flags
) |
4218 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
4222 #ifdef CONFIG_COMPAT
4223 static int do_compat_sigaltstack(const compat_stack_t __user
*uss_ptr
,
4224 compat_stack_t __user
*uoss_ptr
)
4230 compat_stack_t uss32
;
4231 if (copy_from_user(&uss32
, uss_ptr
, sizeof(compat_stack_t
)))
4233 uss
.ss_sp
= compat_ptr(uss32
.ss_sp
);
4234 uss
.ss_flags
= uss32
.ss_flags
;
4235 uss
.ss_size
= uss32
.ss_size
;
4237 ret
= do_sigaltstack(uss_ptr
? &uss
: NULL
, &uoss
,
4238 compat_user_stack_pointer(),
4239 COMPAT_MINSIGSTKSZ
);
4240 if (ret
>= 0 && uoss_ptr
) {
4242 memset(&old
, 0, sizeof(old
));
4243 old
.ss_sp
= ptr_to_compat(uoss
.ss_sp
);
4244 old
.ss_flags
= uoss
.ss_flags
;
4245 old
.ss_size
= uoss
.ss_size
;
4246 if (copy_to_user(uoss_ptr
, &old
, sizeof(compat_stack_t
)))
4252 COMPAT_SYSCALL_DEFINE2(sigaltstack
,
4253 const compat_stack_t __user
*, uss_ptr
,
4254 compat_stack_t __user
*, uoss_ptr
)
4256 return do_compat_sigaltstack(uss_ptr
, uoss_ptr
);
4259 int compat_restore_altstack(const compat_stack_t __user
*uss
)
4261 int err
= do_compat_sigaltstack(uss
, NULL
);
4262 /* squash all but -EFAULT for now */
4263 return err
== -EFAULT
? err
: 0;
4266 int __compat_save_altstack(compat_stack_t __user
*uss
, unsigned long sp
)
4269 struct task_struct
*t
= current
;
4270 err
= __put_user(ptr_to_compat((void __user
*)t
->sas_ss_sp
),
4272 __put_user(t
->sas_ss_flags
, &uss
->ss_flags
) |
4273 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
4278 #ifdef __ARCH_WANT_SYS_SIGPENDING
4281 * sys_sigpending - examine pending signals
4282 * @uset: where mask of pending signal is returned
4284 SYSCALL_DEFINE1(sigpending
, old_sigset_t __user
*, uset
)
4288 if (sizeof(old_sigset_t
) > sizeof(*uset
))
4291 do_sigpending(&set
);
4293 if (copy_to_user(uset
, &set
, sizeof(old_sigset_t
)))
4299 #ifdef CONFIG_COMPAT
4300 COMPAT_SYSCALL_DEFINE1(sigpending
, compat_old_sigset_t __user
*, set32
)
4304 do_sigpending(&set
);
4306 return put_user(set
.sig
[0], set32
);
4312 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4314 * sys_sigprocmask - examine and change blocked signals
4315 * @how: whether to add, remove, or set signals
4316 * @nset: signals to add or remove (if non-null)
4317 * @oset: previous value of signal mask if non-null
4319 * Some platforms have their own version with special arguments;
4320 * others support only sys_rt_sigprocmask.
4323 SYSCALL_DEFINE3(sigprocmask
, int, how
, old_sigset_t __user
*, nset
,
4324 old_sigset_t __user
*, oset
)
4326 old_sigset_t old_set
, new_set
;
4327 sigset_t new_blocked
;
4329 old_set
= current
->blocked
.sig
[0];
4332 if (copy_from_user(&new_set
, nset
, sizeof(*nset
)))
4335 new_blocked
= current
->blocked
;
4339 sigaddsetmask(&new_blocked
, new_set
);
4342 sigdelsetmask(&new_blocked
, new_set
);
4345 new_blocked
.sig
[0] = new_set
;
4351 set_current_blocked(&new_blocked
);
4355 if (copy_to_user(oset
, &old_set
, sizeof(*oset
)))
4361 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4363 #ifndef CONFIG_ODD_RT_SIGACTION
4365 * sys_rt_sigaction - alter an action taken by a process
4366 * @sig: signal to be sent
4367 * @act: new sigaction
4368 * @oact: used to save the previous sigaction
4369 * @sigsetsize: size of sigset_t type
4371 SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
4372 const struct sigaction __user
*, act
,
4373 struct sigaction __user
*, oact
,
4376 struct k_sigaction new_sa
, old_sa
;
4379 /* XXX: Don't preclude handling different sized sigset_t's. */
4380 if (sigsetsize
!= sizeof(sigset_t
))
4383 if (act
&& copy_from_user(&new_sa
.sa
, act
, sizeof(new_sa
.sa
)))
4386 ret
= do_sigaction(sig
, act
? &new_sa
: NULL
, oact
? &old_sa
: NULL
);
4390 if (oact
&& copy_to_user(oact
, &old_sa
.sa
, sizeof(old_sa
.sa
)))
4395 #ifdef CONFIG_COMPAT
4396 COMPAT_SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
4397 const struct compat_sigaction __user
*, act
,
4398 struct compat_sigaction __user
*, oact
,
4399 compat_size_t
, sigsetsize
)
4401 struct k_sigaction new_ka
, old_ka
;
4402 #ifdef __ARCH_HAS_SA_RESTORER
4403 compat_uptr_t restorer
;
4407 /* XXX: Don't preclude handling different sized sigset_t's. */
4408 if (sigsetsize
!= sizeof(compat_sigset_t
))
4412 compat_uptr_t handler
;
4413 ret
= get_user(handler
, &act
->sa_handler
);
4414 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
4415 #ifdef __ARCH_HAS_SA_RESTORER
4416 ret
|= get_user(restorer
, &act
->sa_restorer
);
4417 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
4419 ret
|= get_compat_sigset(&new_ka
.sa
.sa_mask
, &act
->sa_mask
);
4420 ret
|= get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
);
4425 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
4427 ret
= put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
4429 ret
|= put_compat_sigset(&oact
->sa_mask
, &old_ka
.sa
.sa_mask
,
4430 sizeof(oact
->sa_mask
));
4431 ret
|= put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
);
4432 #ifdef __ARCH_HAS_SA_RESTORER
4433 ret
|= put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
4434 &oact
->sa_restorer
);
4440 #endif /* !CONFIG_ODD_RT_SIGACTION */
4442 #ifdef CONFIG_OLD_SIGACTION
4443 SYSCALL_DEFINE3(sigaction
, int, sig
,
4444 const struct old_sigaction __user
*, act
,
4445 struct old_sigaction __user
*, oact
)
4447 struct k_sigaction new_ka
, old_ka
;
4452 if (!access_ok(act
, sizeof(*act
)) ||
4453 __get_user(new_ka
.sa
.sa_handler
, &act
->sa_handler
) ||
4454 __get_user(new_ka
.sa
.sa_restorer
, &act
->sa_restorer
) ||
4455 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
4456 __get_user(mask
, &act
->sa_mask
))
4458 #ifdef __ARCH_HAS_KA_RESTORER
4459 new_ka
.ka_restorer
= NULL
;
4461 siginitset(&new_ka
.sa
.sa_mask
, mask
);
4464 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
4467 if (!access_ok(oact
, sizeof(*oact
)) ||
4468 __put_user(old_ka
.sa
.sa_handler
, &oact
->sa_handler
) ||
4469 __put_user(old_ka
.sa
.sa_restorer
, &oact
->sa_restorer
) ||
4470 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
4471 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
4478 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4479 COMPAT_SYSCALL_DEFINE3(sigaction
, int, sig
,
4480 const struct compat_old_sigaction __user
*, act
,
4481 struct compat_old_sigaction __user
*, oact
)
4483 struct k_sigaction new_ka
, old_ka
;
4485 compat_old_sigset_t mask
;
4486 compat_uptr_t handler
, restorer
;
4489 if (!access_ok(act
, sizeof(*act
)) ||
4490 __get_user(handler
, &act
->sa_handler
) ||
4491 __get_user(restorer
, &act
->sa_restorer
) ||
4492 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
4493 __get_user(mask
, &act
->sa_mask
))
4496 #ifdef __ARCH_HAS_KA_RESTORER
4497 new_ka
.ka_restorer
= NULL
;
4499 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
4500 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
4501 siginitset(&new_ka
.sa
.sa_mask
, mask
);
4504 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
4507 if (!access_ok(oact
, sizeof(*oact
)) ||
4508 __put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
4509 &oact
->sa_handler
) ||
4510 __put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
4511 &oact
->sa_restorer
) ||
4512 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
4513 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
4520 #ifdef CONFIG_SGETMASK_SYSCALL
4523 * For backwards compatibility. Functionality superseded by sigprocmask.
4525 SYSCALL_DEFINE0(sgetmask
)
4528 return current
->blocked
.sig
[0];
4531 SYSCALL_DEFINE1(ssetmask
, int, newmask
)
4533 int old
= current
->blocked
.sig
[0];
4536 siginitset(&newset
, newmask
);
4537 set_current_blocked(&newset
);
4541 #endif /* CONFIG_SGETMASK_SYSCALL */
4543 #ifdef __ARCH_WANT_SYS_SIGNAL
4545 * For backwards compatibility. Functionality superseded by sigaction.
4547 SYSCALL_DEFINE2(signal
, int, sig
, __sighandler_t
, handler
)
4549 struct k_sigaction new_sa
, old_sa
;
4552 new_sa
.sa
.sa_handler
= handler
;
4553 new_sa
.sa
.sa_flags
= SA_ONESHOT
| SA_NOMASK
;
4554 sigemptyset(&new_sa
.sa
.sa_mask
);
4556 ret
= do_sigaction(sig
, &new_sa
, &old_sa
);
4558 return ret
? ret
: (unsigned long)old_sa
.sa
.sa_handler
;
4560 #endif /* __ARCH_WANT_SYS_SIGNAL */
4562 #ifdef __ARCH_WANT_SYS_PAUSE
4564 SYSCALL_DEFINE0(pause
)
4566 while (!signal_pending(current
)) {
4567 __set_current_state(TASK_INTERRUPTIBLE
);
4570 return -ERESTARTNOHAND
;
4575 static int sigsuspend(sigset_t
*set
)
4577 current
->saved_sigmask
= current
->blocked
;
4578 set_current_blocked(set
);
4580 while (!signal_pending(current
)) {
4581 __set_current_state(TASK_INTERRUPTIBLE
);
4584 set_restore_sigmask();
4585 return -ERESTARTNOHAND
;
4589 * sys_rt_sigsuspend - replace the signal mask for a value with the
4590 * @unewset value until a signal is received
4591 * @unewset: new signal mask value
4592 * @sigsetsize: size of sigset_t type
4594 SYSCALL_DEFINE2(rt_sigsuspend
, sigset_t __user
*, unewset
, size_t, sigsetsize
)
4598 /* XXX: Don't preclude handling different sized sigset_t's. */
4599 if (sigsetsize
!= sizeof(sigset_t
))
4602 if (copy_from_user(&newset
, unewset
, sizeof(newset
)))
4604 return sigsuspend(&newset
);
4607 #ifdef CONFIG_COMPAT
4608 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend
, compat_sigset_t __user
*, unewset
, compat_size_t
, sigsetsize
)
4612 /* XXX: Don't preclude handling different sized sigset_t's. */
4613 if (sigsetsize
!= sizeof(sigset_t
))
4616 if (get_compat_sigset(&newset
, unewset
))
4618 return sigsuspend(&newset
);
4622 #ifdef CONFIG_OLD_SIGSUSPEND
4623 SYSCALL_DEFINE1(sigsuspend
, old_sigset_t
, mask
)
4626 siginitset(&blocked
, mask
);
4627 return sigsuspend(&blocked
);
4630 #ifdef CONFIG_OLD_SIGSUSPEND3
4631 SYSCALL_DEFINE3(sigsuspend
, int, unused1
, int, unused2
, old_sigset_t
, mask
)
4634 siginitset(&blocked
, mask
);
4635 return sigsuspend(&blocked
);
4639 __weak
const char *arch_vma_name(struct vm_area_struct
*vma
)
4644 static inline void siginfo_buildtime_checks(void)
4646 BUILD_BUG_ON(sizeof(struct siginfo
) != SI_MAX_SIZE
);
4648 /* Verify the offsets in the two siginfos match */
4649 #define CHECK_OFFSET(field) \
4650 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4653 CHECK_OFFSET(si_pid
);
4654 CHECK_OFFSET(si_uid
);
4657 CHECK_OFFSET(si_tid
);
4658 CHECK_OFFSET(si_overrun
);
4659 CHECK_OFFSET(si_value
);
4662 CHECK_OFFSET(si_pid
);
4663 CHECK_OFFSET(si_uid
);
4664 CHECK_OFFSET(si_value
);
4667 CHECK_OFFSET(si_pid
);
4668 CHECK_OFFSET(si_uid
);
4669 CHECK_OFFSET(si_status
);
4670 CHECK_OFFSET(si_utime
);
4671 CHECK_OFFSET(si_stime
);
4674 CHECK_OFFSET(si_addr
);
4675 CHECK_OFFSET(si_trapno
);
4676 CHECK_OFFSET(si_addr_lsb
);
4677 CHECK_OFFSET(si_lower
);
4678 CHECK_OFFSET(si_upper
);
4679 CHECK_OFFSET(si_pkey
);
4680 CHECK_OFFSET(si_perf_data
);
4681 CHECK_OFFSET(si_perf_type
);
4684 CHECK_OFFSET(si_band
);
4685 CHECK_OFFSET(si_fd
);
4688 CHECK_OFFSET(si_call_addr
);
4689 CHECK_OFFSET(si_syscall
);
4690 CHECK_OFFSET(si_arch
);
4694 BUILD_BUG_ON(offsetof(struct siginfo
, si_pid
) !=
4695 offsetof(struct siginfo
, si_addr
));
4696 if (sizeof(int) == sizeof(void __user
*)) {
4697 BUILD_BUG_ON(sizeof_field(struct siginfo
, si_pid
) !=
4698 sizeof(void __user
*));
4700 BUILD_BUG_ON((sizeof_field(struct siginfo
, si_pid
) +
4701 sizeof_field(struct siginfo
, si_uid
)) !=
4702 sizeof(void __user
*));
4703 BUILD_BUG_ON(offsetofend(struct siginfo
, si_pid
) !=
4704 offsetof(struct siginfo
, si_uid
));
4706 #ifdef CONFIG_COMPAT
4707 BUILD_BUG_ON(offsetof(struct compat_siginfo
, si_pid
) !=
4708 offsetof(struct compat_siginfo
, si_addr
));
4709 BUILD_BUG_ON(sizeof_field(struct compat_siginfo
, si_pid
) !=
4710 sizeof(compat_uptr_t
));
4711 BUILD_BUG_ON(sizeof_field(struct compat_siginfo
, si_pid
) !=
4712 sizeof_field(struct siginfo
, si_pid
));
4716 void __init
signals_init(void)
4718 siginfo_buildtime_checks();
4720 sigqueue_cachep
= KMEM_CACHE(sigqueue
, SLAB_PANIC
| SLAB_ACCOUNT
);
4723 #ifdef CONFIG_KGDB_KDB
4724 #include <linux/kdb.h>
4726 * kdb_send_sig - Allows kdb to send signals without exposing
4727 * signal internals. This function checks if the required locks are
4728 * available before calling the main signal code, to avoid kdb
4731 void kdb_send_sig(struct task_struct
*t
, int sig
)
4733 static struct task_struct
*kdb_prev_t
;
4735 if (!spin_trylock(&t
->sighand
->siglock
)) {
4736 kdb_printf("Can't do kill command now.\n"
4737 "The sigmask lock is held somewhere else in "
4738 "kernel, try again later\n");
4741 new_t
= kdb_prev_t
!= t
;
4743 if (!task_is_running(t
) && new_t
) {
4744 spin_unlock(&t
->sighand
->siglock
);
4745 kdb_printf("Process is not RUNNING, sending a signal from "
4746 "kdb risks deadlock\n"
4747 "on the run queue locks. "
4748 "The signal has _not_ been sent.\n"
4749 "Reissue the kill command if you want to risk "
4753 ret
= send_signal(sig
, SEND_SIG_PRIV
, t
, PIDTYPE_PID
);
4754 spin_unlock(&t
->sighand
->siglock
);
4756 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4759 kdb_printf("Signal %d is sent to process %d.\n", sig
, t
->pid
);
4761 #endif /* CONFIG_KGDB_KDB */