2 * linux/kernel/signal.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson
8 * 2003-06-02 Jim Houston - Concurrent Computer Corp.
9 * Changes to use preallocated sigqueue structures
10 * to allow signals to be sent reliably.
13 #include <linux/slab.h>
14 #include <linux/export.h>
15 #include <linux/init.h>
16 #include <linux/sched/mm.h>
17 #include <linux/sched/user.h>
18 #include <linux/sched/debug.h>
19 #include <linux/sched/task.h>
20 #include <linux/sched/task_stack.h>
21 #include <linux/sched/cputime.h>
22 #include <linux/file.h>
24 #include <linux/proc_fs.h>
25 #include <linux/tty.h>
26 #include <linux/binfmts.h>
27 #include <linux/coredump.h>
28 #include <linux/security.h>
29 #include <linux/syscalls.h>
30 #include <linux/ptrace.h>
31 #include <linux/signal.h>
32 #include <linux/signalfd.h>
33 #include <linux/ratelimit.h>
34 #include <linux/tracehook.h>
35 #include <linux/capability.h>
36 #include <linux/freezer.h>
37 #include <linux/pid_namespace.h>
38 #include <linux/nsproxy.h>
39 #include <linux/user_namespace.h>
40 #include <linux/uprobes.h>
41 #include <linux/compat.h>
42 #include <linux/cn_proc.h>
43 #include <linux/compiler.h>
44 #include <linux/posix-timers.h>
45 #include <linux/oom.h>
46 #include <linux/capability.h>
48 #define CREATE_TRACE_POINTS
49 #include <trace/events/signal.h>
51 #include <asm/param.h>
52 #include <linux/uaccess.h>
53 #include <asm/unistd.h>
54 #include <asm/siginfo.h>
55 #include <asm/cacheflush.h>
56 #include "audit.h" /* audit_signal_info() */
59 * SLAB caches for signal bits.
62 static struct kmem_cache
*sigqueue_cachep
;
64 int print_fatal_signals __read_mostly
;
66 static void __user
*sig_handler(struct task_struct
*t
, int sig
)
68 return t
->sighand
->action
[sig
- 1].sa
.sa_handler
;
71 static int sig_handler_ignored(void __user
*handler
, int sig
)
73 /* Is it explicitly or implicitly ignored? */
74 return handler
== SIG_IGN
||
75 (handler
== SIG_DFL
&& sig_kernel_ignore(sig
));
78 static int sig_task_ignored(struct task_struct
*t
, int sig
, bool force
)
82 handler
= sig_handler(t
, sig
);
84 if (unlikely(t
->signal
->flags
& SIGNAL_UNKILLABLE
) &&
85 handler
== SIG_DFL
&& !(force
&& sig_kernel_only(sig
)))
88 return sig_handler_ignored(handler
, sig
);
91 static int sig_ignored(struct task_struct
*t
, int sig
, bool force
)
94 * Blocked signals are never ignored, since the
95 * signal handler may change by the time it is
98 if (sigismember(&t
->blocked
, sig
) || sigismember(&t
->real_blocked
, sig
))
102 * Tracers may want to know about even ignored signal unless it
103 * is SIGKILL which can't be reported anyway but can be ignored
104 * by SIGNAL_UNKILLABLE task.
106 if (t
->ptrace
&& sig
!= SIGKILL
)
109 return sig_task_ignored(t
, sig
, force
);
113 * Re-calculate pending state from the set of locally pending
114 * signals, globally pending signals, and blocked signals.
116 static inline int has_pending_signals(sigset_t
*signal
, sigset_t
*blocked
)
121 switch (_NSIG_WORDS
) {
123 for (i
= _NSIG_WORDS
, ready
= 0; --i
>= 0 ;)
124 ready
|= signal
->sig
[i
] &~ blocked
->sig
[i
];
127 case 4: ready
= signal
->sig
[3] &~ blocked
->sig
[3];
128 ready
|= signal
->sig
[2] &~ blocked
->sig
[2];
129 ready
|= signal
->sig
[1] &~ blocked
->sig
[1];
130 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
133 case 2: ready
= signal
->sig
[1] &~ blocked
->sig
[1];
134 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
137 case 1: ready
= signal
->sig
[0] &~ blocked
->sig
[0];
142 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
144 static int recalc_sigpending_tsk(struct task_struct
*t
)
146 if ((t
->jobctl
& JOBCTL_PENDING_MASK
) ||
147 PENDING(&t
->pending
, &t
->blocked
) ||
148 PENDING(&t
->signal
->shared_pending
, &t
->blocked
)) {
149 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
153 * We must never clear the flag in another thread, or in current
154 * when it's possible the current syscall is returning -ERESTART*.
155 * So we don't clear it here, and only callers who know they should do.
161 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
162 * This is superfluous when called on current, the wakeup is a harmless no-op.
164 void recalc_sigpending_and_wake(struct task_struct
*t
)
166 if (recalc_sigpending_tsk(t
))
167 signal_wake_up(t
, 0);
170 void recalc_sigpending(void)
172 if (!recalc_sigpending_tsk(current
) && !freezing(current
))
173 clear_thread_flag(TIF_SIGPENDING
);
177 /* Given the mask, find the first available signal that should be serviced. */
179 #define SYNCHRONOUS_MASK \
180 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
181 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
183 int next_signal(struct sigpending
*pending
, sigset_t
*mask
)
185 unsigned long i
, *s
, *m
, x
;
188 s
= pending
->signal
.sig
;
192 * Handle the first word specially: it contains the
193 * synchronous signals that need to be dequeued first.
197 if (x
& SYNCHRONOUS_MASK
)
198 x
&= SYNCHRONOUS_MASK
;
203 switch (_NSIG_WORDS
) {
205 for (i
= 1; i
< _NSIG_WORDS
; ++i
) {
209 sig
= ffz(~x
) + i
*_NSIG_BPW
+ 1;
218 sig
= ffz(~x
) + _NSIG_BPW
+ 1;
229 static inline void print_dropped_signal(int sig
)
231 static DEFINE_RATELIMIT_STATE(ratelimit_state
, 5 * HZ
, 10);
233 if (!print_fatal_signals
)
236 if (!__ratelimit(&ratelimit_state
))
239 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
240 current
->comm
, current
->pid
, sig
);
244 * task_set_jobctl_pending - set jobctl pending bits
246 * @mask: pending bits to set
248 * Clear @mask from @task->jobctl. @mask must be subset of
249 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
250 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
251 * cleared. If @task is already being killed or exiting, this function
255 * Must be called with @task->sighand->siglock held.
258 * %true if @mask is set, %false if made noop because @task was dying.
260 bool task_set_jobctl_pending(struct task_struct
*task
, unsigned long mask
)
262 BUG_ON(mask
& ~(JOBCTL_PENDING_MASK
| JOBCTL_STOP_CONSUME
|
263 JOBCTL_STOP_SIGMASK
| JOBCTL_TRAPPING
));
264 BUG_ON((mask
& JOBCTL_TRAPPING
) && !(mask
& JOBCTL_PENDING_MASK
));
266 if (unlikely(fatal_signal_pending(task
) || (task
->flags
& PF_EXITING
)))
269 if (mask
& JOBCTL_STOP_SIGMASK
)
270 task
->jobctl
&= ~JOBCTL_STOP_SIGMASK
;
272 task
->jobctl
|= mask
;
277 * task_clear_jobctl_trapping - clear jobctl trapping bit
280 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
281 * Clear it and wake up the ptracer. Note that we don't need any further
282 * locking. @task->siglock guarantees that @task->parent points to the
286 * Must be called with @task->sighand->siglock held.
288 void task_clear_jobctl_trapping(struct task_struct
*task
)
290 if (unlikely(task
->jobctl
& JOBCTL_TRAPPING
)) {
291 task
->jobctl
&= ~JOBCTL_TRAPPING
;
292 smp_mb(); /* advised by wake_up_bit() */
293 wake_up_bit(&task
->jobctl
, JOBCTL_TRAPPING_BIT
);
298 * task_clear_jobctl_pending - clear jobctl pending bits
300 * @mask: pending bits to clear
302 * Clear @mask from @task->jobctl. @mask must be subset of
303 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
304 * STOP bits are cleared together.
306 * If clearing of @mask leaves no stop or trap pending, this function calls
307 * task_clear_jobctl_trapping().
310 * Must be called with @task->sighand->siglock held.
312 void task_clear_jobctl_pending(struct task_struct
*task
, unsigned long mask
)
314 BUG_ON(mask
& ~JOBCTL_PENDING_MASK
);
316 if (mask
& JOBCTL_STOP_PENDING
)
317 mask
|= JOBCTL_STOP_CONSUME
| JOBCTL_STOP_DEQUEUED
;
319 task
->jobctl
&= ~mask
;
321 if (!(task
->jobctl
& JOBCTL_PENDING_MASK
))
322 task_clear_jobctl_trapping(task
);
326 * task_participate_group_stop - participate in a group stop
327 * @task: task participating in a group stop
329 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
330 * Group stop states are cleared and the group stop count is consumed if
331 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
332 * stop, the appropriate %SIGNAL_* flags are set.
335 * Must be called with @task->sighand->siglock held.
338 * %true if group stop completion should be notified to the parent, %false
341 static bool task_participate_group_stop(struct task_struct
*task
)
343 struct signal_struct
*sig
= task
->signal
;
344 bool consume
= task
->jobctl
& JOBCTL_STOP_CONSUME
;
346 WARN_ON_ONCE(!(task
->jobctl
& JOBCTL_STOP_PENDING
));
348 task_clear_jobctl_pending(task
, JOBCTL_STOP_PENDING
);
353 if (!WARN_ON_ONCE(sig
->group_stop_count
== 0))
354 sig
->group_stop_count
--;
357 * Tell the caller to notify completion iff we are entering into a
358 * fresh group stop. Read comment in do_signal_stop() for details.
360 if (!sig
->group_stop_count
&& !(sig
->flags
& SIGNAL_STOP_STOPPED
)) {
361 signal_set_stop_flags(sig
, SIGNAL_STOP_STOPPED
);
368 * allocate a new signal queue record
369 * - this may be called without locks if and only if t == current, otherwise an
370 * appropriate lock must be held to stop the target task from exiting
372 static struct sigqueue
*
373 __sigqueue_alloc(int sig
, struct task_struct
*t
, gfp_t flags
, int override_rlimit
)
375 struct sigqueue
*q
= NULL
;
376 struct user_struct
*user
;
379 * Protect access to @t credentials. This can go away when all
380 * callers hold rcu read lock.
383 user
= get_uid(__task_cred(t
)->user
);
384 atomic_inc(&user
->sigpending
);
387 if (override_rlimit
||
388 atomic_read(&user
->sigpending
) <=
389 task_rlimit(t
, RLIMIT_SIGPENDING
)) {
390 q
= kmem_cache_alloc(sigqueue_cachep
, flags
);
392 print_dropped_signal(sig
);
395 if (unlikely(q
== NULL
)) {
396 atomic_dec(&user
->sigpending
);
399 INIT_LIST_HEAD(&q
->list
);
407 static void __sigqueue_free(struct sigqueue
*q
)
409 if (q
->flags
& SIGQUEUE_PREALLOC
)
411 atomic_dec(&q
->user
->sigpending
);
413 kmem_cache_free(sigqueue_cachep
, q
);
416 void flush_sigqueue(struct sigpending
*queue
)
420 sigemptyset(&queue
->signal
);
421 while (!list_empty(&queue
->list
)) {
422 q
= list_entry(queue
->list
.next
, struct sigqueue
, list
);
423 list_del_init(&q
->list
);
429 * Flush all pending signals for this kthread.
431 void flush_signals(struct task_struct
*t
)
435 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
436 clear_tsk_thread_flag(t
, TIF_SIGPENDING
);
437 flush_sigqueue(&t
->pending
);
438 flush_sigqueue(&t
->signal
->shared_pending
);
439 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
442 #ifdef CONFIG_POSIX_TIMERS
443 static void __flush_itimer_signals(struct sigpending
*pending
)
445 sigset_t signal
, retain
;
446 struct sigqueue
*q
, *n
;
448 signal
= pending
->signal
;
449 sigemptyset(&retain
);
451 list_for_each_entry_safe(q
, n
, &pending
->list
, list
) {
452 int sig
= q
->info
.si_signo
;
454 if (likely(q
->info
.si_code
!= SI_TIMER
)) {
455 sigaddset(&retain
, sig
);
457 sigdelset(&signal
, sig
);
458 list_del_init(&q
->list
);
463 sigorsets(&pending
->signal
, &signal
, &retain
);
466 void flush_itimer_signals(void)
468 struct task_struct
*tsk
= current
;
471 spin_lock_irqsave(&tsk
->sighand
->siglock
, flags
);
472 __flush_itimer_signals(&tsk
->pending
);
473 __flush_itimer_signals(&tsk
->signal
->shared_pending
);
474 spin_unlock_irqrestore(&tsk
->sighand
->siglock
, flags
);
478 void ignore_signals(struct task_struct
*t
)
482 for (i
= 0; i
< _NSIG
; ++i
)
483 t
->sighand
->action
[i
].sa
.sa_handler
= SIG_IGN
;
489 * Flush all handlers for a task.
493 flush_signal_handlers(struct task_struct
*t
, int force_default
)
496 struct k_sigaction
*ka
= &t
->sighand
->action
[0];
497 for (i
= _NSIG
; i
!= 0 ; i
--) {
498 if (force_default
|| ka
->sa
.sa_handler
!= SIG_IGN
)
499 ka
->sa
.sa_handler
= SIG_DFL
;
501 #ifdef __ARCH_HAS_SA_RESTORER
502 ka
->sa
.sa_restorer
= NULL
;
504 sigemptyset(&ka
->sa
.sa_mask
);
509 int unhandled_signal(struct task_struct
*tsk
, int sig
)
511 void __user
*handler
= tsk
->sighand
->action
[sig
-1].sa
.sa_handler
;
512 if (is_global_init(tsk
))
514 if (handler
!= SIG_IGN
&& handler
!= SIG_DFL
)
516 /* if ptraced, let the tracer determine */
520 static void collect_signal(int sig
, struct sigpending
*list
, siginfo_t
*info
,
523 struct sigqueue
*q
, *first
= NULL
;
526 * Collect the siginfo appropriate to this signal. Check if
527 * there is another siginfo for the same signal.
529 list_for_each_entry(q
, &list
->list
, list
) {
530 if (q
->info
.si_signo
== sig
) {
537 sigdelset(&list
->signal
, sig
);
541 list_del_init(&first
->list
);
542 copy_siginfo(info
, &first
->info
);
545 (first
->flags
& SIGQUEUE_PREALLOC
) &&
546 (info
->si_code
== SI_TIMER
) &&
547 (info
->si_sys_private
);
549 __sigqueue_free(first
);
552 * Ok, it wasn't in the queue. This must be
553 * a fast-pathed signal or we must have been
554 * out of queue space. So zero out the info.
556 info
->si_signo
= sig
;
558 info
->si_code
= SI_USER
;
564 static int __dequeue_signal(struct sigpending
*pending
, sigset_t
*mask
,
565 siginfo_t
*info
, bool *resched_timer
)
567 int sig
= next_signal(pending
, mask
);
570 collect_signal(sig
, pending
, info
, resched_timer
);
575 * Dequeue a signal and return the element to the caller, which is
576 * expected to free it.
578 * All callers have to hold the siglock.
580 int dequeue_signal(struct task_struct
*tsk
, sigset_t
*mask
, siginfo_t
*info
)
582 bool resched_timer
= false;
585 /* We only dequeue private signals from ourselves, we don't let
586 * signalfd steal them
588 signr
= __dequeue_signal(&tsk
->pending
, mask
, info
, &resched_timer
);
590 signr
= __dequeue_signal(&tsk
->signal
->shared_pending
,
591 mask
, info
, &resched_timer
);
592 #ifdef CONFIG_POSIX_TIMERS
596 * itimers are process shared and we restart periodic
597 * itimers in the signal delivery path to prevent DoS
598 * attacks in the high resolution timer case. This is
599 * compliant with the old way of self-restarting
600 * itimers, as the SIGALRM is a legacy signal and only
601 * queued once. Changing the restart behaviour to
602 * restart the timer in the signal dequeue path is
603 * reducing the timer noise on heavy loaded !highres
606 if (unlikely(signr
== SIGALRM
)) {
607 struct hrtimer
*tmr
= &tsk
->signal
->real_timer
;
609 if (!hrtimer_is_queued(tmr
) &&
610 tsk
->signal
->it_real_incr
!= 0) {
611 hrtimer_forward(tmr
, tmr
->base
->get_time(),
612 tsk
->signal
->it_real_incr
);
613 hrtimer_restart(tmr
);
623 if (unlikely(sig_kernel_stop(signr
))) {
625 * Set a marker that we have dequeued a stop signal. Our
626 * caller might release the siglock and then the pending
627 * stop signal it is about to process is no longer in the
628 * pending bitmasks, but must still be cleared by a SIGCONT
629 * (and overruled by a SIGKILL). So those cases clear this
630 * shared flag after we've set it. Note that this flag may
631 * remain set after the signal we return is ignored or
632 * handled. That doesn't matter because its only purpose
633 * is to alert stop-signal processing code when another
634 * processor has come along and cleared the flag.
636 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
638 #ifdef CONFIG_POSIX_TIMERS
641 * Release the siglock to ensure proper locking order
642 * of timer locks outside of siglocks. Note, we leave
643 * irqs disabled here, since the posix-timers code is
644 * about to disable them again anyway.
646 spin_unlock(&tsk
->sighand
->siglock
);
647 posixtimer_rearm(info
);
648 spin_lock(&tsk
->sighand
->siglock
);
655 * Tell a process that it has a new active signal..
657 * NOTE! we rely on the previous spin_lock to
658 * lock interrupts for us! We can only be called with
659 * "siglock" held, and the local interrupt must
660 * have been disabled when that got acquired!
662 * No need to set need_resched since signal event passing
663 * goes through ->blocked
665 void signal_wake_up_state(struct task_struct
*t
, unsigned int state
)
667 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
669 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
670 * case. We don't check t->state here because there is a race with it
671 * executing another processor and just now entering stopped state.
672 * By using wake_up_state, we ensure the process will wake up and
673 * handle its death signal.
675 if (!wake_up_state(t
, state
| TASK_INTERRUPTIBLE
))
679 static int dequeue_synchronous_signal(siginfo_t
*info
)
681 struct task_struct
*tsk
= current
;
682 struct sigpending
*pending
= &tsk
->pending
;
683 struct sigqueue
*q
, *sync
= NULL
;
686 * Might a synchronous signal be in the queue?
688 if (!((pending
->signal
.sig
[0] & ~tsk
->blocked
.sig
[0]) & SYNCHRONOUS_MASK
))
692 * Return the first synchronous signal in the queue.
694 list_for_each_entry(q
, &pending
->list
, list
) {
695 /* Synchronous signals have a postive si_code */
696 if ((q
->info
.si_code
> SI_USER
) &&
697 (sigmask(q
->info
.si_signo
) & SYNCHRONOUS_MASK
)) {
705 * Check if there is another siginfo for the same signal.
707 list_for_each_entry_continue(q
, &pending
->list
, list
) {
708 if (q
->info
.si_signo
== sync
->info
.si_signo
)
712 sigdelset(&pending
->signal
, sync
->info
.si_signo
);
715 list_del_init(&sync
->list
);
716 copy_siginfo(info
, &sync
->info
);
717 __sigqueue_free(sync
);
718 return info
->si_signo
;
722 * Remove signals in mask from the pending set and queue.
723 * Returns 1 if any signals were found.
725 * All callers must be holding the siglock.
727 static int flush_sigqueue_mask(sigset_t
*mask
, struct sigpending
*s
)
729 struct sigqueue
*q
, *n
;
732 sigandsets(&m
, mask
, &s
->signal
);
733 if (sigisemptyset(&m
))
736 sigandnsets(&s
->signal
, &s
->signal
, mask
);
737 list_for_each_entry_safe(q
, n
, &s
->list
, list
) {
738 if (sigismember(mask
, q
->info
.si_signo
)) {
739 list_del_init(&q
->list
);
746 static inline int is_si_special(const struct siginfo
*info
)
748 return info
<= SEND_SIG_FORCED
;
751 static inline bool si_fromuser(const struct siginfo
*info
)
753 return info
== SEND_SIG_NOINFO
||
754 (!is_si_special(info
) && SI_FROMUSER(info
));
758 * called with RCU read lock from check_kill_permission()
760 static int kill_ok_by_cred(struct task_struct
*t
)
762 const struct cred
*cred
= current_cred();
763 const struct cred
*tcred
= __task_cred(t
);
765 if (uid_eq(cred
->euid
, tcred
->suid
) ||
766 uid_eq(cred
->euid
, tcred
->uid
) ||
767 uid_eq(cred
->uid
, tcred
->suid
) ||
768 uid_eq(cred
->uid
, tcred
->uid
))
771 if (ns_capable(tcred
->user_ns
, CAP_KILL
))
778 * Bad permissions for sending the signal
779 * - the caller must hold the RCU read lock
781 static int check_kill_permission(int sig
, struct siginfo
*info
,
782 struct task_struct
*t
)
787 if (!valid_signal(sig
))
790 if (!si_fromuser(info
))
793 error
= audit_signal_info(sig
, t
); /* Let audit system see the signal */
797 if (!same_thread_group(current
, t
) &&
798 !kill_ok_by_cred(t
)) {
801 sid
= task_session(t
);
803 * We don't return the error if sid == NULL. The
804 * task was unhashed, the caller must notice this.
806 if (!sid
|| sid
== task_session(current
))
813 return security_task_kill(t
, info
, sig
, 0);
817 * ptrace_trap_notify - schedule trap to notify ptracer
818 * @t: tracee wanting to notify tracer
820 * This function schedules sticky ptrace trap which is cleared on the next
821 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
824 * If @t is running, STOP trap will be taken. If trapped for STOP and
825 * ptracer is listening for events, tracee is woken up so that it can
826 * re-trap for the new event. If trapped otherwise, STOP trap will be
827 * eventually taken without returning to userland after the existing traps
828 * are finished by PTRACE_CONT.
831 * Must be called with @task->sighand->siglock held.
833 static void ptrace_trap_notify(struct task_struct
*t
)
835 WARN_ON_ONCE(!(t
->ptrace
& PT_SEIZED
));
836 assert_spin_locked(&t
->sighand
->siglock
);
838 task_set_jobctl_pending(t
, JOBCTL_TRAP_NOTIFY
);
839 ptrace_signal_wake_up(t
, t
->jobctl
& JOBCTL_LISTENING
);
843 * Handle magic process-wide effects of stop/continue signals. Unlike
844 * the signal actions, these happen immediately at signal-generation
845 * time regardless of blocking, ignoring, or handling. This does the
846 * actual continuing for SIGCONT, but not the actual stopping for stop
847 * signals. The process stop is done as a signal action for SIG_DFL.
849 * Returns true if the signal should be actually delivered, otherwise
850 * it should be dropped.
852 static bool prepare_signal(int sig
, struct task_struct
*p
, bool force
)
854 struct signal_struct
*signal
= p
->signal
;
855 struct task_struct
*t
;
858 if (signal
->flags
& (SIGNAL_GROUP_EXIT
| SIGNAL_GROUP_COREDUMP
)) {
859 if (!(signal
->flags
& SIGNAL_GROUP_EXIT
))
860 return sig
== SIGKILL
;
862 * The process is in the middle of dying, nothing to do.
864 } else if (sig_kernel_stop(sig
)) {
866 * This is a stop signal. Remove SIGCONT from all queues.
868 siginitset(&flush
, sigmask(SIGCONT
));
869 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
870 for_each_thread(p
, t
)
871 flush_sigqueue_mask(&flush
, &t
->pending
);
872 } else if (sig
== SIGCONT
) {
875 * Remove all stop signals from all queues, wake all threads.
877 siginitset(&flush
, SIG_KERNEL_STOP_MASK
);
878 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
879 for_each_thread(p
, t
) {
880 flush_sigqueue_mask(&flush
, &t
->pending
);
881 task_clear_jobctl_pending(t
, JOBCTL_STOP_PENDING
);
882 if (likely(!(t
->ptrace
& PT_SEIZED
)))
883 wake_up_state(t
, __TASK_STOPPED
);
885 ptrace_trap_notify(t
);
889 * Notify the parent with CLD_CONTINUED if we were stopped.
891 * If we were in the middle of a group stop, we pretend it
892 * was already finished, and then continued. Since SIGCHLD
893 * doesn't queue we report only CLD_STOPPED, as if the next
894 * CLD_CONTINUED was dropped.
897 if (signal
->flags
& SIGNAL_STOP_STOPPED
)
898 why
|= SIGNAL_CLD_CONTINUED
;
899 else if (signal
->group_stop_count
)
900 why
|= SIGNAL_CLD_STOPPED
;
904 * The first thread which returns from do_signal_stop()
905 * will take ->siglock, notice SIGNAL_CLD_MASK, and
906 * notify its parent. See get_signal_to_deliver().
908 signal_set_stop_flags(signal
, why
| SIGNAL_STOP_CONTINUED
);
909 signal
->group_stop_count
= 0;
910 signal
->group_exit_code
= 0;
914 return !sig_ignored(p
, sig
, force
);
918 * Test if P wants to take SIG. After we've checked all threads with this,
919 * it's equivalent to finding no threads not blocking SIG. Any threads not
920 * blocking SIG were ruled out because they are not running and already
921 * have pending signals. Such threads will dequeue from the shared queue
922 * as soon as they're available, so putting the signal on the shared queue
923 * will be equivalent to sending it to one such thread.
925 static inline int wants_signal(int sig
, struct task_struct
*p
)
927 if (sigismember(&p
->blocked
, sig
))
929 if (p
->flags
& PF_EXITING
)
933 if (task_is_stopped_or_traced(p
))
935 return task_curr(p
) || !signal_pending(p
);
938 static void complete_signal(int sig
, struct task_struct
*p
, int group
)
940 struct signal_struct
*signal
= p
->signal
;
941 struct task_struct
*t
;
944 * Now find a thread we can wake up to take the signal off the queue.
946 * If the main thread wants the signal, it gets first crack.
947 * Probably the least surprising to the average bear.
949 if (wants_signal(sig
, p
))
951 else if (!group
|| thread_group_empty(p
))
953 * There is just one thread and it does not need to be woken.
954 * It will dequeue unblocked signals before it runs again.
959 * Otherwise try to find a suitable thread.
961 t
= signal
->curr_target
;
962 while (!wants_signal(sig
, t
)) {
964 if (t
== signal
->curr_target
)
966 * No thread needs to be woken.
967 * Any eligible threads will see
968 * the signal in the queue soon.
972 signal
->curr_target
= t
;
976 * Found a killable thread. If the signal will be fatal,
977 * then start taking the whole group down immediately.
979 if (sig_fatal(p
, sig
) &&
980 !(signal
->flags
& SIGNAL_GROUP_EXIT
) &&
981 !sigismember(&t
->real_blocked
, sig
) &&
982 (sig
== SIGKILL
|| !p
->ptrace
)) {
984 * This signal will be fatal to the whole group.
986 if (!sig_kernel_coredump(sig
)) {
988 * Start a group exit and wake everybody up.
989 * This way we don't have other threads
990 * running and doing things after a slower
991 * thread has the fatal signal pending.
993 signal
->flags
= SIGNAL_GROUP_EXIT
;
994 signal
->group_exit_code
= sig
;
995 signal
->group_stop_count
= 0;
998 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
999 sigaddset(&t
->pending
.signal
, SIGKILL
);
1000 signal_wake_up(t
, 1);
1001 } while_each_thread(p
, t
);
1007 * The signal is already in the shared-pending queue.
1008 * Tell the chosen thread to wake up and dequeue it.
1010 signal_wake_up(t
, sig
== SIGKILL
);
1014 static inline int legacy_queue(struct sigpending
*signals
, int sig
)
1016 return (sig
< SIGRTMIN
) && sigismember(&signals
->signal
, sig
);
1019 #ifdef CONFIG_USER_NS
1020 static inline void userns_fixup_signal_uid(struct siginfo
*info
, struct task_struct
*t
)
1022 if (current_user_ns() == task_cred_xxx(t
, user_ns
))
1025 if (SI_FROMKERNEL(info
))
1029 info
->si_uid
= from_kuid_munged(task_cred_xxx(t
, user_ns
),
1030 make_kuid(current_user_ns(), info
->si_uid
));
1034 static inline void userns_fixup_signal_uid(struct siginfo
*info
, struct task_struct
*t
)
1040 static int __send_signal(int sig
, struct siginfo
*info
, struct task_struct
*t
,
1041 int group
, int from_ancestor_ns
)
1043 struct sigpending
*pending
;
1045 int override_rlimit
;
1046 int ret
= 0, result
;
1048 assert_spin_locked(&t
->sighand
->siglock
);
1050 result
= TRACE_SIGNAL_IGNORED
;
1051 if (!prepare_signal(sig
, t
,
1052 from_ancestor_ns
|| (info
== SEND_SIG_PRIV
) || (info
== SEND_SIG_FORCED
)))
1055 pending
= group
? &t
->signal
->shared_pending
: &t
->pending
;
1057 * Short-circuit ignored signals and support queuing
1058 * exactly one non-rt signal, so that we can get more
1059 * detailed information about the cause of the signal.
1061 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1062 if (legacy_queue(pending
, sig
))
1065 result
= TRACE_SIGNAL_DELIVERED
;
1067 * fast-pathed signals for kernel-internal things like SIGSTOP
1070 if (info
== SEND_SIG_FORCED
)
1074 * Real-time signals must be queued if sent by sigqueue, or
1075 * some other real-time mechanism. It is implementation
1076 * defined whether kill() does so. We attempt to do so, on
1077 * the principle of least surprise, but since kill is not
1078 * allowed to fail with EAGAIN when low on memory we just
1079 * make sure at least one signal gets delivered and don't
1080 * pass on the info struct.
1083 override_rlimit
= (is_si_special(info
) || info
->si_code
>= 0);
1085 override_rlimit
= 0;
1087 q
= __sigqueue_alloc(sig
, t
, GFP_ATOMIC
, override_rlimit
);
1089 list_add_tail(&q
->list
, &pending
->list
);
1090 switch ((unsigned long) info
) {
1091 case (unsigned long) SEND_SIG_NOINFO
:
1092 q
->info
.si_signo
= sig
;
1093 q
->info
.si_errno
= 0;
1094 q
->info
.si_code
= SI_USER
;
1095 q
->info
.si_pid
= task_tgid_nr_ns(current
,
1096 task_active_pid_ns(t
));
1097 q
->info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
1099 case (unsigned long) SEND_SIG_PRIV
:
1100 q
->info
.si_signo
= sig
;
1101 q
->info
.si_errno
= 0;
1102 q
->info
.si_code
= SI_KERNEL
;
1107 copy_siginfo(&q
->info
, info
);
1108 if (from_ancestor_ns
)
1113 userns_fixup_signal_uid(&q
->info
, t
);
1115 } else if (!is_si_special(info
)) {
1116 if (sig
>= SIGRTMIN
&& info
->si_code
!= SI_USER
) {
1118 * Queue overflow, abort. We may abort if the
1119 * signal was rt and sent by user using something
1120 * other than kill().
1122 result
= TRACE_SIGNAL_OVERFLOW_FAIL
;
1127 * This is a silent loss of information. We still
1128 * send the signal, but the *info bits are lost.
1130 result
= TRACE_SIGNAL_LOSE_INFO
;
1135 signalfd_notify(t
, sig
);
1136 sigaddset(&pending
->signal
, sig
);
1137 complete_signal(sig
, t
, group
);
1139 trace_signal_generate(sig
, info
, t
, group
, result
);
1143 static int send_signal(int sig
, struct siginfo
*info
, struct task_struct
*t
,
1146 int from_ancestor_ns
= 0;
1148 #ifdef CONFIG_PID_NS
1149 from_ancestor_ns
= si_fromuser(info
) &&
1150 !task_pid_nr_ns(current
, task_active_pid_ns(t
));
1153 return __send_signal(sig
, info
, t
, group
, from_ancestor_ns
);
1156 static void print_fatal_signal(int signr
)
1158 struct pt_regs
*regs
= signal_pt_regs();
1159 pr_info("potentially unexpected fatal signal %d.\n", signr
);
1161 #if defined(__i386__) && !defined(__arch_um__)
1162 pr_info("code at %08lx: ", regs
->ip
);
1165 for (i
= 0; i
< 16; i
++) {
1168 if (get_user(insn
, (unsigned char *)(regs
->ip
+ i
)))
1170 pr_cont("%02x ", insn
);
1180 static int __init
setup_print_fatal_signals(char *str
)
1182 get_option (&str
, &print_fatal_signals
);
1187 __setup("print-fatal-signals=", setup_print_fatal_signals
);
1190 __group_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1192 return send_signal(sig
, info
, p
, 1);
1196 specific_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*t
)
1198 return send_signal(sig
, info
, t
, 0);
1201 int do_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
,
1204 unsigned long flags
;
1207 if (lock_task_sighand(p
, &flags
)) {
1208 ret
= send_signal(sig
, info
, p
, group
);
1209 unlock_task_sighand(p
, &flags
);
1216 * Force a signal that the process can't ignore: if necessary
1217 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1219 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1220 * since we do not want to have a signal handler that was blocked
1221 * be invoked when user space had explicitly blocked it.
1223 * We don't want to have recursive SIGSEGV's etc, for example,
1224 * that is why we also clear SIGNAL_UNKILLABLE.
1227 force_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*t
)
1229 unsigned long int flags
;
1230 int ret
, blocked
, ignored
;
1231 struct k_sigaction
*action
;
1233 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
1234 action
= &t
->sighand
->action
[sig
-1];
1235 ignored
= action
->sa
.sa_handler
== SIG_IGN
;
1236 blocked
= sigismember(&t
->blocked
, sig
);
1237 if (blocked
|| ignored
) {
1238 action
->sa
.sa_handler
= SIG_DFL
;
1240 sigdelset(&t
->blocked
, sig
);
1241 recalc_sigpending_and_wake(t
);
1245 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1246 * debugging to leave init killable.
1248 if (action
->sa
.sa_handler
== SIG_DFL
&& !t
->ptrace
)
1249 t
->signal
->flags
&= ~SIGNAL_UNKILLABLE
;
1250 ret
= specific_send_sig_info(sig
, info
, t
);
1251 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
1257 * Nuke all other threads in the group.
1259 int zap_other_threads(struct task_struct
*p
)
1261 struct task_struct
*t
= p
;
1264 p
->signal
->group_stop_count
= 0;
1266 while_each_thread(p
, t
) {
1267 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
1270 /* Don't bother with already dead threads */
1273 sigaddset(&t
->pending
.signal
, SIGKILL
);
1274 signal_wake_up(t
, 1);
1280 struct sighand_struct
*__lock_task_sighand(struct task_struct
*tsk
,
1281 unsigned long *flags
)
1283 struct sighand_struct
*sighand
;
1287 * Disable interrupts early to avoid deadlocks.
1288 * See rcu_read_unlock() comment header for details.
1290 local_irq_save(*flags
);
1292 sighand
= rcu_dereference(tsk
->sighand
);
1293 if (unlikely(sighand
== NULL
)) {
1295 local_irq_restore(*flags
);
1299 * This sighand can be already freed and even reused, but
1300 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1301 * initializes ->siglock: this slab can't go away, it has
1302 * the same object type, ->siglock can't be reinitialized.
1304 * We need to ensure that tsk->sighand is still the same
1305 * after we take the lock, we can race with de_thread() or
1306 * __exit_signal(). In the latter case the next iteration
1307 * must see ->sighand == NULL.
1309 spin_lock(&sighand
->siglock
);
1310 if (likely(sighand
== tsk
->sighand
)) {
1314 spin_unlock(&sighand
->siglock
);
1316 local_irq_restore(*flags
);
1323 * send signal info to all the members of a group
1325 int group_send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1330 ret
= check_kill_permission(sig
, info
, p
);
1334 ret
= do_send_sig_info(sig
, info
, p
, true);
1335 if (capable(CAP_KILL
) && sig
== SIGKILL
)
1336 add_to_oom_reaper(p
);
1343 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1344 * control characters do (^C, ^Z etc)
1345 * - the caller must hold at least a readlock on tasklist_lock
1347 int __kill_pgrp_info(int sig
, struct siginfo
*info
, struct pid
*pgrp
)
1349 struct task_struct
*p
= NULL
;
1350 int retval
, success
;
1354 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
1355 int err
= group_send_sig_info(sig
, info
, p
);
1358 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
1359 return success
? 0 : retval
;
1362 int kill_pid_info(int sig
, struct siginfo
*info
, struct pid
*pid
)
1365 struct task_struct
*p
;
1369 p
= pid_task(pid
, PIDTYPE_PID
);
1371 error
= group_send_sig_info(sig
, info
, p
);
1373 if (likely(!p
|| error
!= -ESRCH
))
1377 * The task was unhashed in between, try again. If it
1378 * is dead, pid_task() will return NULL, if we race with
1379 * de_thread() it will find the new leader.
1384 static int kill_proc_info(int sig
, struct siginfo
*info
, pid_t pid
)
1388 error
= kill_pid_info(sig
, info
, find_vpid(pid
));
1393 static int kill_as_cred_perm(const struct cred
*cred
,
1394 struct task_struct
*target
)
1396 const struct cred
*pcred
= __task_cred(target
);
1397 if (!uid_eq(cred
->euid
, pcred
->suid
) && !uid_eq(cred
->euid
, pcred
->uid
) &&
1398 !uid_eq(cred
->uid
, pcred
->suid
) && !uid_eq(cred
->uid
, pcred
->uid
))
1403 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
1404 int kill_pid_info_as_cred(int sig
, struct siginfo
*info
, struct pid
*pid
,
1405 const struct cred
*cred
, u32 secid
)
1408 struct task_struct
*p
;
1409 unsigned long flags
;
1411 if (!valid_signal(sig
))
1415 p
= pid_task(pid
, PIDTYPE_PID
);
1420 if (si_fromuser(info
) && !kill_as_cred_perm(cred
, p
)) {
1424 ret
= security_task_kill(p
, info
, sig
, secid
);
1429 if (lock_task_sighand(p
, &flags
)) {
1430 ret
= __send_signal(sig
, info
, p
, 1, 0);
1431 unlock_task_sighand(p
, &flags
);
1439 EXPORT_SYMBOL_GPL(kill_pid_info_as_cred
);
1442 * kill_something_info() interprets pid in interesting ways just like kill(2).
1444 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1445 * is probably wrong. Should make it like BSD or SYSV.
1448 static int kill_something_info(int sig
, struct siginfo
*info
, pid_t pid
)
1454 ret
= kill_pid_info(sig
, info
, find_vpid(pid
));
1459 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1463 read_lock(&tasklist_lock
);
1465 ret
= __kill_pgrp_info(sig
, info
,
1466 pid
? find_vpid(-pid
) : task_pgrp(current
));
1468 int retval
= 0, count
= 0;
1469 struct task_struct
* p
;
1471 for_each_process(p
) {
1472 if (task_pid_vnr(p
) > 1 &&
1473 !same_thread_group(p
, current
)) {
1474 int err
= group_send_sig_info(sig
, info
, p
);
1480 ret
= count
? retval
: -ESRCH
;
1482 read_unlock(&tasklist_lock
);
1488 * These are for backward compatibility with the rest of the kernel source.
1491 int send_sig_info(int sig
, struct siginfo
*info
, struct task_struct
*p
)
1494 * Make sure legacy kernel users don't send in bad values
1495 * (normal paths check this in check_kill_permission).
1497 if (!valid_signal(sig
))
1500 return do_send_sig_info(sig
, info
, p
, false);
1503 #define __si_special(priv) \
1504 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1507 send_sig(int sig
, struct task_struct
*p
, int priv
)
1509 return send_sig_info(sig
, __si_special(priv
), p
);
1513 force_sig(int sig
, struct task_struct
*p
)
1515 force_sig_info(sig
, SEND_SIG_PRIV
, p
);
1519 * When things go south during signal handling, we
1520 * will force a SIGSEGV. And if the signal that caused
1521 * the problem was already a SIGSEGV, we'll want to
1522 * make sure we don't even try to deliver the signal..
1525 force_sigsegv(int sig
, struct task_struct
*p
)
1527 if (sig
== SIGSEGV
) {
1528 unsigned long flags
;
1529 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
1530 p
->sighand
->action
[sig
- 1].sa
.sa_handler
= SIG_DFL
;
1531 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
1533 force_sig(SIGSEGV
, p
);
1537 int kill_pgrp(struct pid
*pid
, int sig
, int priv
)
1541 read_lock(&tasklist_lock
);
1542 ret
= __kill_pgrp_info(sig
, __si_special(priv
), pid
);
1543 read_unlock(&tasklist_lock
);
1547 EXPORT_SYMBOL(kill_pgrp
);
1549 int kill_pid(struct pid
*pid
, int sig
, int priv
)
1551 return kill_pid_info(sig
, __si_special(priv
), pid
);
1553 EXPORT_SYMBOL(kill_pid
);
1556 * These functions support sending signals using preallocated sigqueue
1557 * structures. This is needed "because realtime applications cannot
1558 * afford to lose notifications of asynchronous events, like timer
1559 * expirations or I/O completions". In the case of POSIX Timers
1560 * we allocate the sigqueue structure from the timer_create. If this
1561 * allocation fails we are able to report the failure to the application
1562 * with an EAGAIN error.
1564 struct sigqueue
*sigqueue_alloc(void)
1566 struct sigqueue
*q
= __sigqueue_alloc(-1, current
, GFP_KERNEL
, 0);
1569 q
->flags
|= SIGQUEUE_PREALLOC
;
1574 void sigqueue_free(struct sigqueue
*q
)
1576 unsigned long flags
;
1577 spinlock_t
*lock
= ¤t
->sighand
->siglock
;
1579 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1581 * We must hold ->siglock while testing q->list
1582 * to serialize with collect_signal() or with
1583 * __exit_signal()->flush_sigqueue().
1585 spin_lock_irqsave(lock
, flags
);
1586 q
->flags
&= ~SIGQUEUE_PREALLOC
;
1588 * If it is queued it will be freed when dequeued,
1589 * like the "regular" sigqueue.
1591 if (!list_empty(&q
->list
))
1593 spin_unlock_irqrestore(lock
, flags
);
1599 int send_sigqueue(struct sigqueue
*q
, struct task_struct
*t
, int group
)
1601 int sig
= q
->info
.si_signo
;
1602 struct sigpending
*pending
;
1603 unsigned long flags
;
1606 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1609 if (!likely(lock_task_sighand(t
, &flags
)))
1612 ret
= 1; /* the signal is ignored */
1613 result
= TRACE_SIGNAL_IGNORED
;
1614 if (!prepare_signal(sig
, t
, false))
1618 if (unlikely(!list_empty(&q
->list
))) {
1620 * If an SI_TIMER entry is already queue just increment
1621 * the overrun count.
1623 BUG_ON(q
->info
.si_code
!= SI_TIMER
);
1624 q
->info
.si_overrun
++;
1625 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1628 q
->info
.si_overrun
= 0;
1630 signalfd_notify(t
, sig
);
1631 pending
= group
? &t
->signal
->shared_pending
: &t
->pending
;
1632 list_add_tail(&q
->list
, &pending
->list
);
1633 sigaddset(&pending
->signal
, sig
);
1634 complete_signal(sig
, t
, group
);
1635 result
= TRACE_SIGNAL_DELIVERED
;
1637 trace_signal_generate(sig
, &q
->info
, t
, group
, result
);
1638 unlock_task_sighand(t
, &flags
);
1644 * Let a parent know about the death of a child.
1645 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1647 * Returns true if our parent ignored us and so we've switched to
1650 bool do_notify_parent(struct task_struct
*tsk
, int sig
)
1652 struct siginfo info
;
1653 unsigned long flags
;
1654 struct sighand_struct
*psig
;
1655 bool autoreap
= false;
1660 /* do_notify_parent_cldstop should have been called instead. */
1661 BUG_ON(task_is_stopped_or_traced(tsk
));
1663 BUG_ON(!tsk
->ptrace
&&
1664 (tsk
->group_leader
!= tsk
|| !thread_group_empty(tsk
)));
1666 if (sig
!= SIGCHLD
) {
1668 * This is only possible if parent == real_parent.
1669 * Check if it has changed security domain.
1671 if (tsk
->parent_exec_id
!= tsk
->parent
->self_exec_id
)
1675 info
.si_signo
= sig
;
1678 * We are under tasklist_lock here so our parent is tied to
1679 * us and cannot change.
1681 * task_active_pid_ns will always return the same pid namespace
1682 * until a task passes through release_task.
1684 * write_lock() currently calls preempt_disable() which is the
1685 * same as rcu_read_lock(), but according to Oleg, this is not
1686 * correct to rely on this
1689 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(tsk
->parent
));
1690 info
.si_uid
= from_kuid_munged(task_cred_xxx(tsk
->parent
, user_ns
),
1694 task_cputime(tsk
, &utime
, &stime
);
1695 info
.si_utime
= nsec_to_clock_t(utime
+ tsk
->signal
->utime
);
1696 info
.si_stime
= nsec_to_clock_t(stime
+ tsk
->signal
->stime
);
1698 info
.si_status
= tsk
->exit_code
& 0x7f;
1699 if (tsk
->exit_code
& 0x80)
1700 info
.si_code
= CLD_DUMPED
;
1701 else if (tsk
->exit_code
& 0x7f)
1702 info
.si_code
= CLD_KILLED
;
1704 info
.si_code
= CLD_EXITED
;
1705 info
.si_status
= tsk
->exit_code
>> 8;
1708 psig
= tsk
->parent
->sighand
;
1709 spin_lock_irqsave(&psig
->siglock
, flags
);
1710 if (!tsk
->ptrace
&& sig
== SIGCHLD
&&
1711 (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
||
1712 (psig
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDWAIT
))) {
1714 * We are exiting and our parent doesn't care. POSIX.1
1715 * defines special semantics for setting SIGCHLD to SIG_IGN
1716 * or setting the SA_NOCLDWAIT flag: we should be reaped
1717 * automatically and not left for our parent's wait4 call.
1718 * Rather than having the parent do it as a magic kind of
1719 * signal handler, we just set this to tell do_exit that we
1720 * can be cleaned up without becoming a zombie. Note that
1721 * we still call __wake_up_parent in this case, because a
1722 * blocked sys_wait4 might now return -ECHILD.
1724 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1725 * is implementation-defined: we do (if you don't want
1726 * it, just use SIG_IGN instead).
1729 if (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
)
1732 if (valid_signal(sig
) && sig
)
1733 __group_send_sig_info(sig
, &info
, tsk
->parent
);
1734 __wake_up_parent(tsk
, tsk
->parent
);
1735 spin_unlock_irqrestore(&psig
->siglock
, flags
);
1741 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1742 * @tsk: task reporting the state change
1743 * @for_ptracer: the notification is for ptracer
1744 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1746 * Notify @tsk's parent that the stopped/continued state has changed. If
1747 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1748 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1751 * Must be called with tasklist_lock at least read locked.
1753 static void do_notify_parent_cldstop(struct task_struct
*tsk
,
1754 bool for_ptracer
, int why
)
1756 struct siginfo info
;
1757 unsigned long flags
;
1758 struct task_struct
*parent
;
1759 struct sighand_struct
*sighand
;
1763 parent
= tsk
->parent
;
1765 tsk
= tsk
->group_leader
;
1766 parent
= tsk
->real_parent
;
1769 info
.si_signo
= SIGCHLD
;
1772 * see comment in do_notify_parent() about the following 4 lines
1775 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(parent
));
1776 info
.si_uid
= from_kuid_munged(task_cred_xxx(parent
, user_ns
), task_uid(tsk
));
1779 task_cputime(tsk
, &utime
, &stime
);
1780 info
.si_utime
= nsec_to_clock_t(utime
);
1781 info
.si_stime
= nsec_to_clock_t(stime
);
1786 info
.si_status
= SIGCONT
;
1789 info
.si_status
= tsk
->signal
->group_exit_code
& 0x7f;
1792 info
.si_status
= tsk
->exit_code
& 0x7f;
1798 sighand
= parent
->sighand
;
1799 spin_lock_irqsave(&sighand
->siglock
, flags
);
1800 if (sighand
->action
[SIGCHLD
-1].sa
.sa_handler
!= SIG_IGN
&&
1801 !(sighand
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDSTOP
))
1802 __group_send_sig_info(SIGCHLD
, &info
, parent
);
1804 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
1806 __wake_up_parent(tsk
, parent
);
1807 spin_unlock_irqrestore(&sighand
->siglock
, flags
);
1810 static inline int may_ptrace_stop(void)
1812 if (!likely(current
->ptrace
))
1815 * Are we in the middle of do_coredump?
1816 * If so and our tracer is also part of the coredump stopping
1817 * is a deadlock situation, and pointless because our tracer
1818 * is dead so don't allow us to stop.
1819 * If SIGKILL was already sent before the caller unlocked
1820 * ->siglock we must see ->core_state != NULL. Otherwise it
1821 * is safe to enter schedule().
1823 * This is almost outdated, a task with the pending SIGKILL can't
1824 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
1825 * after SIGKILL was already dequeued.
1827 if (unlikely(current
->mm
->core_state
) &&
1828 unlikely(current
->mm
== current
->parent
->mm
))
1835 * Return non-zero if there is a SIGKILL that should be waking us up.
1836 * Called with the siglock held.
1838 static int sigkill_pending(struct task_struct
*tsk
)
1840 return sigismember(&tsk
->pending
.signal
, SIGKILL
) ||
1841 sigismember(&tsk
->signal
->shared_pending
.signal
, SIGKILL
);
1845 * This must be called with current->sighand->siglock held.
1847 * This should be the path for all ptrace stops.
1848 * We always set current->last_siginfo while stopped here.
1849 * That makes it a way to test a stopped process for
1850 * being ptrace-stopped vs being job-control-stopped.
1852 * If we actually decide not to stop at all because the tracer
1853 * is gone, we keep current->exit_code unless clear_code.
1855 static void ptrace_stop(int exit_code
, int why
, int clear_code
, siginfo_t
*info
)
1856 __releases(¤t
->sighand
->siglock
)
1857 __acquires(¤t
->sighand
->siglock
)
1859 bool gstop_done
= false;
1861 if (arch_ptrace_stop_needed(exit_code
, info
)) {
1863 * The arch code has something special to do before a
1864 * ptrace stop. This is allowed to block, e.g. for faults
1865 * on user stack pages. We can't keep the siglock while
1866 * calling arch_ptrace_stop, so we must release it now.
1867 * To preserve proper semantics, we must do this before
1868 * any signal bookkeeping like checking group_stop_count.
1869 * Meanwhile, a SIGKILL could come in before we retake the
1870 * siglock. That must prevent us from sleeping in TASK_TRACED.
1871 * So after regaining the lock, we must check for SIGKILL.
1873 spin_unlock_irq(¤t
->sighand
->siglock
);
1874 arch_ptrace_stop(exit_code
, info
);
1875 spin_lock_irq(¤t
->sighand
->siglock
);
1876 if (sigkill_pending(current
))
1880 set_special_state(TASK_TRACED
);
1883 * We're committing to trapping. TRACED should be visible before
1884 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
1885 * Also, transition to TRACED and updates to ->jobctl should be
1886 * atomic with respect to siglock and should be done after the arch
1887 * hook as siglock is released and regrabbed across it.
1892 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
1894 * set_current_state() smp_wmb();
1896 * wait_task_stopped()
1897 * task_stopped_code()
1898 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
1902 current
->last_siginfo
= info
;
1903 current
->exit_code
= exit_code
;
1906 * If @why is CLD_STOPPED, we're trapping to participate in a group
1907 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
1908 * across siglock relocks since INTERRUPT was scheduled, PENDING
1909 * could be clear now. We act as if SIGCONT is received after
1910 * TASK_TRACED is entered - ignore it.
1912 if (why
== CLD_STOPPED
&& (current
->jobctl
& JOBCTL_STOP_PENDING
))
1913 gstop_done
= task_participate_group_stop(current
);
1915 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
1916 task_clear_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
1917 if (info
&& info
->si_code
>> 8 == PTRACE_EVENT_STOP
)
1918 task_clear_jobctl_pending(current
, JOBCTL_TRAP_NOTIFY
);
1920 /* entering a trap, clear TRAPPING */
1921 task_clear_jobctl_trapping(current
);
1923 spin_unlock_irq(¤t
->sighand
->siglock
);
1924 read_lock(&tasklist_lock
);
1925 if (may_ptrace_stop()) {
1927 * Notify parents of the stop.
1929 * While ptraced, there are two parents - the ptracer and
1930 * the real_parent of the group_leader. The ptracer should
1931 * know about every stop while the real parent is only
1932 * interested in the completion of group stop. The states
1933 * for the two don't interact with each other. Notify
1934 * separately unless they're gonna be duplicates.
1936 do_notify_parent_cldstop(current
, true, why
);
1937 if (gstop_done
&& ptrace_reparented(current
))
1938 do_notify_parent_cldstop(current
, false, why
);
1941 * Don't want to allow preemption here, because
1942 * sys_ptrace() needs this task to be inactive.
1944 * XXX: implement read_unlock_no_resched().
1947 read_unlock(&tasklist_lock
);
1948 preempt_enable_no_resched();
1949 freezable_schedule();
1952 * By the time we got the lock, our tracer went away.
1953 * Don't drop the lock yet, another tracer may come.
1955 * If @gstop_done, the ptracer went away between group stop
1956 * completion and here. During detach, it would have set
1957 * JOBCTL_STOP_PENDING on us and we'll re-enter
1958 * TASK_STOPPED in do_signal_stop() on return, so notifying
1959 * the real parent of the group stop completion is enough.
1962 do_notify_parent_cldstop(current
, false, why
);
1964 /* tasklist protects us from ptrace_freeze_traced() */
1965 __set_current_state(TASK_RUNNING
);
1967 current
->exit_code
= 0;
1968 read_unlock(&tasklist_lock
);
1972 * We are back. Now reacquire the siglock before touching
1973 * last_siginfo, so that we are sure to have synchronized with
1974 * any signal-sending on another CPU that wants to examine it.
1976 spin_lock_irq(¤t
->sighand
->siglock
);
1977 current
->last_siginfo
= NULL
;
1979 /* LISTENING can be set only during STOP traps, clear it */
1980 current
->jobctl
&= ~JOBCTL_LISTENING
;
1983 * Queued signals ignored us while we were stopped for tracing.
1984 * So check for any that we should take before resuming user mode.
1985 * This sets TIF_SIGPENDING, but never clears it.
1987 recalc_sigpending_tsk(current
);
1990 static void ptrace_do_notify(int signr
, int exit_code
, int why
)
1994 memset(&info
, 0, sizeof info
);
1995 info
.si_signo
= signr
;
1996 info
.si_code
= exit_code
;
1997 info
.si_pid
= task_pid_vnr(current
);
1998 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
2000 /* Let the debugger run. */
2001 ptrace_stop(exit_code
, why
, 1, &info
);
2004 void ptrace_notify(int exit_code
)
2006 BUG_ON((exit_code
& (0x7f | ~0xffff)) != SIGTRAP
);
2007 if (unlikely(current
->task_works
))
2010 spin_lock_irq(¤t
->sighand
->siglock
);
2011 ptrace_do_notify(SIGTRAP
, exit_code
, CLD_TRAPPED
);
2012 spin_unlock_irq(¤t
->sighand
->siglock
);
2016 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2017 * @signr: signr causing group stop if initiating
2019 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2020 * and participate in it. If already set, participate in the existing
2021 * group stop. If participated in a group stop (and thus slept), %true is
2022 * returned with siglock released.
2024 * If ptraced, this function doesn't handle stop itself. Instead,
2025 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2026 * untouched. The caller must ensure that INTERRUPT trap handling takes
2027 * places afterwards.
2030 * Must be called with @current->sighand->siglock held, which is released
2034 * %false if group stop is already cancelled or ptrace trap is scheduled.
2035 * %true if participated in group stop.
2037 static bool do_signal_stop(int signr
)
2038 __releases(¤t
->sighand
->siglock
)
2040 struct signal_struct
*sig
= current
->signal
;
2042 if (!(current
->jobctl
& JOBCTL_STOP_PENDING
)) {
2043 unsigned long gstop
= JOBCTL_STOP_PENDING
| JOBCTL_STOP_CONSUME
;
2044 struct task_struct
*t
;
2046 /* signr will be recorded in task->jobctl for retries */
2047 WARN_ON_ONCE(signr
& ~JOBCTL_STOP_SIGMASK
);
2049 if (!likely(current
->jobctl
& JOBCTL_STOP_DEQUEUED
) ||
2050 unlikely(signal_group_exit(sig
)))
2053 * There is no group stop already in progress. We must
2056 * While ptraced, a task may be resumed while group stop is
2057 * still in effect and then receive a stop signal and
2058 * initiate another group stop. This deviates from the
2059 * usual behavior as two consecutive stop signals can't
2060 * cause two group stops when !ptraced. That is why we
2061 * also check !task_is_stopped(t) below.
2063 * The condition can be distinguished by testing whether
2064 * SIGNAL_STOP_STOPPED is already set. Don't generate
2065 * group_exit_code in such case.
2067 * This is not necessary for SIGNAL_STOP_CONTINUED because
2068 * an intervening stop signal is required to cause two
2069 * continued events regardless of ptrace.
2071 if (!(sig
->flags
& SIGNAL_STOP_STOPPED
))
2072 sig
->group_exit_code
= signr
;
2074 sig
->group_stop_count
= 0;
2076 if (task_set_jobctl_pending(current
, signr
| gstop
))
2077 sig
->group_stop_count
++;
2080 while_each_thread(current
, t
) {
2082 * Setting state to TASK_STOPPED for a group
2083 * stop is always done with the siglock held,
2084 * so this check has no races.
2086 if (!task_is_stopped(t
) &&
2087 task_set_jobctl_pending(t
, signr
| gstop
)) {
2088 sig
->group_stop_count
++;
2089 if (likely(!(t
->ptrace
& PT_SEIZED
)))
2090 signal_wake_up(t
, 0);
2092 ptrace_trap_notify(t
);
2097 if (likely(!current
->ptrace
)) {
2101 * If there are no other threads in the group, or if there
2102 * is a group stop in progress and we are the last to stop,
2103 * report to the parent.
2105 if (task_participate_group_stop(current
))
2106 notify
= CLD_STOPPED
;
2108 set_special_state(TASK_STOPPED
);
2109 spin_unlock_irq(¤t
->sighand
->siglock
);
2112 * Notify the parent of the group stop completion. Because
2113 * we're not holding either the siglock or tasklist_lock
2114 * here, ptracer may attach inbetween; however, this is for
2115 * group stop and should always be delivered to the real
2116 * parent of the group leader. The new ptracer will get
2117 * its notification when this task transitions into
2121 read_lock(&tasklist_lock
);
2122 do_notify_parent_cldstop(current
, false, notify
);
2123 read_unlock(&tasklist_lock
);
2126 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2127 freezable_schedule();
2131 * While ptraced, group stop is handled by STOP trap.
2132 * Schedule it and let the caller deal with it.
2134 task_set_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
2140 * do_jobctl_trap - take care of ptrace jobctl traps
2142 * When PT_SEIZED, it's used for both group stop and explicit
2143 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2144 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2145 * the stop signal; otherwise, %SIGTRAP.
2147 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2148 * number as exit_code and no siginfo.
2151 * Must be called with @current->sighand->siglock held, which may be
2152 * released and re-acquired before returning with intervening sleep.
2154 static void do_jobctl_trap(void)
2156 struct signal_struct
*signal
= current
->signal
;
2157 int signr
= current
->jobctl
& JOBCTL_STOP_SIGMASK
;
2159 if (current
->ptrace
& PT_SEIZED
) {
2160 if (!signal
->group_stop_count
&&
2161 !(signal
->flags
& SIGNAL_STOP_STOPPED
))
2163 WARN_ON_ONCE(!signr
);
2164 ptrace_do_notify(signr
, signr
| (PTRACE_EVENT_STOP
<< 8),
2167 WARN_ON_ONCE(!signr
);
2168 ptrace_stop(signr
, CLD_STOPPED
, 0, NULL
);
2169 current
->exit_code
= 0;
2173 static int ptrace_signal(int signr
, siginfo_t
*info
)
2176 * We do not check sig_kernel_stop(signr) but set this marker
2177 * unconditionally because we do not know whether debugger will
2178 * change signr. This flag has no meaning unless we are going
2179 * to stop after return from ptrace_stop(). In this case it will
2180 * be checked in do_signal_stop(), we should only stop if it was
2181 * not cleared by SIGCONT while we were sleeping. See also the
2182 * comment in dequeue_signal().
2184 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
2185 ptrace_stop(signr
, CLD_TRAPPED
, 0, info
);
2187 /* We're back. Did the debugger cancel the sig? */
2188 signr
= current
->exit_code
;
2192 current
->exit_code
= 0;
2195 * Update the siginfo structure if the signal has
2196 * changed. If the debugger wanted something
2197 * specific in the siginfo structure then it should
2198 * have updated *info via PTRACE_SETSIGINFO.
2200 if (signr
!= info
->si_signo
) {
2201 info
->si_signo
= signr
;
2203 info
->si_code
= SI_USER
;
2205 info
->si_pid
= task_pid_vnr(current
->parent
);
2206 info
->si_uid
= from_kuid_munged(current_user_ns(),
2207 task_uid(current
->parent
));
2211 /* If the (new) signal is now blocked, requeue it. */
2212 if (sigismember(¤t
->blocked
, signr
)) {
2213 specific_send_sig_info(signr
, info
, current
);
2220 int get_signal(struct ksignal
*ksig
)
2222 struct sighand_struct
*sighand
= current
->sighand
;
2223 struct signal_struct
*signal
= current
->signal
;
2226 if (unlikely(current
->task_works
))
2229 if (unlikely(uprobe_deny_signal()))
2233 * Do this once, we can't return to user-mode if freezing() == T.
2234 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2235 * thus do not need another check after return.
2240 spin_lock_irq(&sighand
->siglock
);
2242 * Every stopped thread goes here after wakeup. Check to see if
2243 * we should notify the parent, prepare_signal(SIGCONT) encodes
2244 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2246 if (unlikely(signal
->flags
& SIGNAL_CLD_MASK
)) {
2249 if (signal
->flags
& SIGNAL_CLD_CONTINUED
)
2250 why
= CLD_CONTINUED
;
2254 signal
->flags
&= ~SIGNAL_CLD_MASK
;
2256 spin_unlock_irq(&sighand
->siglock
);
2259 * Notify the parent that we're continuing. This event is
2260 * always per-process and doesn't make whole lot of sense
2261 * for ptracers, who shouldn't consume the state via
2262 * wait(2) either, but, for backward compatibility, notify
2263 * the ptracer of the group leader too unless it's gonna be
2266 read_lock(&tasklist_lock
);
2267 do_notify_parent_cldstop(current
, false, why
);
2269 if (ptrace_reparented(current
->group_leader
))
2270 do_notify_parent_cldstop(current
->group_leader
,
2272 read_unlock(&tasklist_lock
);
2277 /* Has this task already been marked for death? */
2278 if (signal_group_exit(signal
)) {
2279 ksig
->info
.si_signo
= signr
= SIGKILL
;
2280 sigdelset(¤t
->pending
.signal
, SIGKILL
);
2281 recalc_sigpending();
2286 struct k_sigaction
*ka
;
2288 if (unlikely(current
->jobctl
& JOBCTL_STOP_PENDING
) &&
2292 if (unlikely(current
->jobctl
& JOBCTL_TRAP_MASK
)) {
2294 spin_unlock_irq(&sighand
->siglock
);
2299 * Signals generated by the execution of an instruction
2300 * need to be delivered before any other pending signals
2301 * so that the instruction pointer in the signal stack
2302 * frame points to the faulting instruction.
2304 signr
= dequeue_synchronous_signal(&ksig
->info
);
2306 signr
= dequeue_signal(current
, ¤t
->blocked
, &ksig
->info
);
2309 break; /* will return 0 */
2311 if (unlikely(current
->ptrace
) && signr
!= SIGKILL
) {
2312 signr
= ptrace_signal(signr
, &ksig
->info
);
2317 ka
= &sighand
->action
[signr
-1];
2319 /* Trace actually delivered signals. */
2320 trace_signal_deliver(signr
, &ksig
->info
, ka
);
2322 if (ka
->sa
.sa_handler
== SIG_IGN
) /* Do nothing. */
2324 if (ka
->sa
.sa_handler
!= SIG_DFL
) {
2325 /* Run the handler. */
2328 if (ka
->sa
.sa_flags
& SA_ONESHOT
)
2329 ka
->sa
.sa_handler
= SIG_DFL
;
2331 break; /* will return non-zero "signr" value */
2335 * Now we are doing the default action for this signal.
2337 if (sig_kernel_ignore(signr
)) /* Default is nothing. */
2341 * Global init gets no signals it doesn't want.
2342 * Container-init gets no signals it doesn't want from same
2345 * Note that if global/container-init sees a sig_kernel_only()
2346 * signal here, the signal must have been generated internally
2347 * or must have come from an ancestor namespace. In either
2348 * case, the signal cannot be dropped.
2350 if (unlikely(signal
->flags
& SIGNAL_UNKILLABLE
) &&
2351 !sig_kernel_only(signr
))
2354 if (sig_kernel_stop(signr
)) {
2356 * The default action is to stop all threads in
2357 * the thread group. The job control signals
2358 * do nothing in an orphaned pgrp, but SIGSTOP
2359 * always works. Note that siglock needs to be
2360 * dropped during the call to is_orphaned_pgrp()
2361 * because of lock ordering with tasklist_lock.
2362 * This allows an intervening SIGCONT to be posted.
2363 * We need to check for that and bail out if necessary.
2365 if (signr
!= SIGSTOP
) {
2366 spin_unlock_irq(&sighand
->siglock
);
2368 /* signals can be posted during this window */
2370 if (is_current_pgrp_orphaned())
2373 spin_lock_irq(&sighand
->siglock
);
2376 if (likely(do_signal_stop(ksig
->info
.si_signo
))) {
2377 /* It released the siglock. */
2382 * We didn't actually stop, due to a race
2383 * with SIGCONT or something like that.
2389 spin_unlock_irq(&sighand
->siglock
);
2392 * Anything else is fatal, maybe with a core dump.
2394 current
->flags
|= PF_SIGNALED
;
2396 if (sig_kernel_coredump(signr
)) {
2397 if (print_fatal_signals
)
2398 print_fatal_signal(ksig
->info
.si_signo
);
2399 proc_coredump_connector(current
);
2401 * If it was able to dump core, this kills all
2402 * other threads in the group and synchronizes with
2403 * their demise. If we lost the race with another
2404 * thread getting here, it set group_exit_code
2405 * first and our do_group_exit call below will use
2406 * that value and ignore the one we pass it.
2408 do_coredump(&ksig
->info
);
2412 * Death signals, no core dump.
2414 do_group_exit(ksig
->info
.si_signo
);
2417 spin_unlock_irq(&sighand
->siglock
);
2420 return ksig
->sig
> 0;
2424 * signal_delivered -
2425 * @ksig: kernel signal struct
2426 * @stepping: nonzero if debugger single-step or block-step in use
2428 * This function should be called when a signal has successfully been
2429 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2430 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2431 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2433 static void signal_delivered(struct ksignal
*ksig
, int stepping
)
2437 /* A signal was successfully delivered, and the
2438 saved sigmask was stored on the signal frame,
2439 and will be restored by sigreturn. So we can
2440 simply clear the restore sigmask flag. */
2441 clear_restore_sigmask();
2443 sigorsets(&blocked
, ¤t
->blocked
, &ksig
->ka
.sa
.sa_mask
);
2444 if (!(ksig
->ka
.sa
.sa_flags
& SA_NODEFER
))
2445 sigaddset(&blocked
, ksig
->sig
);
2446 set_current_blocked(&blocked
);
2447 tracehook_signal_handler(stepping
);
2450 void signal_setup_done(int failed
, struct ksignal
*ksig
, int stepping
)
2453 force_sigsegv(ksig
->sig
, current
);
2455 signal_delivered(ksig
, stepping
);
2459 * It could be that complete_signal() picked us to notify about the
2460 * group-wide signal. Other threads should be notified now to take
2461 * the shared signals in @which since we will not.
2463 static void retarget_shared_pending(struct task_struct
*tsk
, sigset_t
*which
)
2466 struct task_struct
*t
;
2468 sigandsets(&retarget
, &tsk
->signal
->shared_pending
.signal
, which
);
2469 if (sigisemptyset(&retarget
))
2473 while_each_thread(tsk
, t
) {
2474 if (t
->flags
& PF_EXITING
)
2477 if (!has_pending_signals(&retarget
, &t
->blocked
))
2479 /* Remove the signals this thread can handle. */
2480 sigandsets(&retarget
, &retarget
, &t
->blocked
);
2482 if (!signal_pending(t
))
2483 signal_wake_up(t
, 0);
2485 if (sigisemptyset(&retarget
))
2490 void exit_signals(struct task_struct
*tsk
)
2496 * @tsk is about to have PF_EXITING set - lock out users which
2497 * expect stable threadgroup.
2499 cgroup_threadgroup_change_begin(tsk
);
2501 if (thread_group_empty(tsk
) || signal_group_exit(tsk
->signal
)) {
2502 tsk
->flags
|= PF_EXITING
;
2503 cgroup_threadgroup_change_end(tsk
);
2507 spin_lock_irq(&tsk
->sighand
->siglock
);
2509 * From now this task is not visible for group-wide signals,
2510 * see wants_signal(), do_signal_stop().
2512 tsk
->flags
|= PF_EXITING
;
2514 cgroup_threadgroup_change_end(tsk
);
2516 if (!signal_pending(tsk
))
2519 unblocked
= tsk
->blocked
;
2520 signotset(&unblocked
);
2521 retarget_shared_pending(tsk
, &unblocked
);
2523 if (unlikely(tsk
->jobctl
& JOBCTL_STOP_PENDING
) &&
2524 task_participate_group_stop(tsk
))
2525 group_stop
= CLD_STOPPED
;
2527 spin_unlock_irq(&tsk
->sighand
->siglock
);
2530 * If group stop has completed, deliver the notification. This
2531 * should always go to the real parent of the group leader.
2533 if (unlikely(group_stop
)) {
2534 read_lock(&tasklist_lock
);
2535 do_notify_parent_cldstop(tsk
, false, group_stop
);
2536 read_unlock(&tasklist_lock
);
2540 EXPORT_SYMBOL(recalc_sigpending
);
2541 EXPORT_SYMBOL_GPL(dequeue_signal
);
2542 EXPORT_SYMBOL(flush_signals
);
2543 EXPORT_SYMBOL(force_sig
);
2544 EXPORT_SYMBOL(send_sig
);
2545 EXPORT_SYMBOL(send_sig_info
);
2546 EXPORT_SYMBOL(sigprocmask
);
2549 * System call entry points.
2553 * sys_restart_syscall - restart a system call
2555 SYSCALL_DEFINE0(restart_syscall
)
2557 struct restart_block
*restart
= ¤t
->restart_block
;
2558 return restart
->fn(restart
);
2561 long do_no_restart_syscall(struct restart_block
*param
)
2566 static void __set_task_blocked(struct task_struct
*tsk
, const sigset_t
*newset
)
2568 if (signal_pending(tsk
) && !thread_group_empty(tsk
)) {
2569 sigset_t newblocked
;
2570 /* A set of now blocked but previously unblocked signals. */
2571 sigandnsets(&newblocked
, newset
, ¤t
->blocked
);
2572 retarget_shared_pending(tsk
, &newblocked
);
2574 tsk
->blocked
= *newset
;
2575 recalc_sigpending();
2579 * set_current_blocked - change current->blocked mask
2582 * It is wrong to change ->blocked directly, this helper should be used
2583 * to ensure the process can't miss a shared signal we are going to block.
2585 void set_current_blocked(sigset_t
*newset
)
2587 sigdelsetmask(newset
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
2588 __set_current_blocked(newset
);
2591 void __set_current_blocked(const sigset_t
*newset
)
2593 struct task_struct
*tsk
= current
;
2596 * In case the signal mask hasn't changed, there is nothing we need
2597 * to do. The current->blocked shouldn't be modified by other task.
2599 if (sigequalsets(&tsk
->blocked
, newset
))
2602 spin_lock_irq(&tsk
->sighand
->siglock
);
2603 __set_task_blocked(tsk
, newset
);
2604 spin_unlock_irq(&tsk
->sighand
->siglock
);
2608 * This is also useful for kernel threads that want to temporarily
2609 * (or permanently) block certain signals.
2611 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2612 * interface happily blocks "unblockable" signals like SIGKILL
2615 int sigprocmask(int how
, sigset_t
*set
, sigset_t
*oldset
)
2617 struct task_struct
*tsk
= current
;
2620 /* Lockless, only current can change ->blocked, never from irq */
2622 *oldset
= tsk
->blocked
;
2626 sigorsets(&newset
, &tsk
->blocked
, set
);
2629 sigandnsets(&newset
, &tsk
->blocked
, set
);
2638 __set_current_blocked(&newset
);
2643 * sys_rt_sigprocmask - change the list of currently blocked signals
2644 * @how: whether to add, remove, or set signals
2645 * @nset: stores pending signals
2646 * @oset: previous value of signal mask if non-null
2647 * @sigsetsize: size of sigset_t type
2649 SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, sigset_t __user
*, nset
,
2650 sigset_t __user
*, oset
, size_t, sigsetsize
)
2652 sigset_t old_set
, new_set
;
2655 /* XXX: Don't preclude handling different sized sigset_t's. */
2656 if (sigsetsize
!= sizeof(sigset_t
))
2659 old_set
= current
->blocked
;
2662 if (copy_from_user(&new_set
, nset
, sizeof(sigset_t
)))
2664 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
2666 error
= sigprocmask(how
, &new_set
, NULL
);
2672 if (copy_to_user(oset
, &old_set
, sizeof(sigset_t
)))
2679 #ifdef CONFIG_COMPAT
2680 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, compat_sigset_t __user
*, nset
,
2681 compat_sigset_t __user
*, oset
, compat_size_t
, sigsetsize
)
2684 sigset_t old_set
= current
->blocked
;
2686 /* XXX: Don't preclude handling different sized sigset_t's. */
2687 if (sigsetsize
!= sizeof(sigset_t
))
2691 compat_sigset_t new32
;
2694 if (copy_from_user(&new32
, nset
, sizeof(compat_sigset_t
)))
2697 sigset_from_compat(&new_set
, &new32
);
2698 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
2700 error
= sigprocmask(how
, &new_set
, NULL
);
2705 compat_sigset_t old32
;
2706 sigset_to_compat(&old32
, &old_set
);
2707 if (copy_to_user(oset
, &old32
, sizeof(compat_sigset_t
)))
2712 return sys_rt_sigprocmask(how
, (sigset_t __user
*)nset
,
2713 (sigset_t __user
*)oset
, sigsetsize
);
2718 static int do_sigpending(void *set
, unsigned long sigsetsize
)
2720 if (sigsetsize
> sizeof(sigset_t
))
2723 spin_lock_irq(¤t
->sighand
->siglock
);
2724 sigorsets(set
, ¤t
->pending
.signal
,
2725 ¤t
->signal
->shared_pending
.signal
);
2726 spin_unlock_irq(¤t
->sighand
->siglock
);
2728 /* Outside the lock because only this thread touches it. */
2729 sigandsets(set
, ¤t
->blocked
, set
);
2734 * sys_rt_sigpending - examine a pending signal that has been raised
2736 * @uset: stores pending signals
2737 * @sigsetsize: size of sigset_t type or larger
2739 SYSCALL_DEFINE2(rt_sigpending
, sigset_t __user
*, uset
, size_t, sigsetsize
)
2742 int err
= do_sigpending(&set
, sigsetsize
);
2743 if (!err
&& copy_to_user(uset
, &set
, sigsetsize
))
2748 #ifdef CONFIG_COMPAT
2749 COMPAT_SYSCALL_DEFINE2(rt_sigpending
, compat_sigset_t __user
*, uset
,
2750 compat_size_t
, sigsetsize
)
2754 int err
= do_sigpending(&set
, sigsetsize
);
2756 compat_sigset_t set32
;
2757 sigset_to_compat(&set32
, &set
);
2758 /* we can get here only if sigsetsize <= sizeof(set) */
2759 if (copy_to_user(uset
, &set32
, sigsetsize
))
2764 return sys_rt_sigpending((sigset_t __user
*)uset
, sigsetsize
);
2769 enum siginfo_layout
siginfo_layout(unsigned sig
, int si_code
)
2771 enum siginfo_layout layout
= SIL_KILL
;
2772 if ((si_code
> SI_USER
) && (si_code
< SI_KERNEL
)) {
2773 static const struct {
2774 unsigned char limit
, layout
;
2776 [SIGILL
] = { NSIGILL
, SIL_FAULT
},
2777 [SIGFPE
] = { NSIGFPE
, SIL_FAULT
},
2778 [SIGSEGV
] = { NSIGSEGV
, SIL_FAULT
},
2779 [SIGBUS
] = { NSIGBUS
, SIL_FAULT
},
2780 [SIGTRAP
] = { NSIGTRAP
, SIL_FAULT
},
2781 #if defined(SIGEMT) && defined(NSIGEMT)
2782 [SIGEMT
] = { NSIGEMT
, SIL_FAULT
},
2784 [SIGCHLD
] = { NSIGCHLD
, SIL_CHLD
},
2785 [SIGPOLL
] = { NSIGPOLL
, SIL_POLL
},
2786 #ifdef __ARCH_SIGSYS
2787 [SIGSYS
] = { NSIGSYS
, SIL_SYS
},
2790 if ((sig
< ARRAY_SIZE(filter
)) && (si_code
<= filter
[sig
].limit
))
2791 layout
= filter
[sig
].layout
;
2792 else if (si_code
<= NSIGPOLL
)
2795 if (si_code
== SI_TIMER
)
2797 else if (si_code
== SI_SIGIO
)
2799 else if (si_code
< 0)
2801 /* Tests to support buggy kernel ABIs */
2803 if ((sig
== SIGTRAP
) && (si_code
== TRAP_FIXME
))
2807 if ((sig
== SIGFPE
) && (si_code
== FPE_FIXME
))
2814 #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER
2816 int copy_siginfo_to_user(siginfo_t __user
*to
, const siginfo_t
*from
)
2820 if (!access_ok (VERIFY_WRITE
, to
, sizeof(siginfo_t
)))
2822 if (from
->si_code
< 0)
2823 return __copy_to_user(to
, from
, sizeof(siginfo_t
))
2826 * If you change siginfo_t structure, please be sure
2827 * this code is fixed accordingly.
2828 * Please remember to update the signalfd_copyinfo() function
2829 * inside fs/signalfd.c too, in case siginfo_t changes.
2830 * It should never copy any pad contained in the structure
2831 * to avoid security leaks, but must copy the generic
2832 * 3 ints plus the relevant union member.
2834 err
= __put_user(from
->si_signo
, &to
->si_signo
);
2835 err
|= __put_user(from
->si_errno
, &to
->si_errno
);
2836 err
|= __put_user(from
->si_code
, &to
->si_code
);
2837 switch (siginfo_layout(from
->si_signo
, from
->si_code
)) {
2839 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2840 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2843 /* Unreached SI_TIMER is negative */
2846 err
|= __put_user(from
->si_band
, &to
->si_band
);
2847 err
|= __put_user(from
->si_fd
, &to
->si_fd
);
2850 err
|= __put_user(from
->si_addr
, &to
->si_addr
);
2851 #ifdef __ARCH_SI_TRAPNO
2852 err
|= __put_user(from
->si_trapno
, &to
->si_trapno
);
2854 #ifdef BUS_MCEERR_AO
2856 * Other callers might not initialize the si_lsb field,
2857 * so check explicitly for the right codes here.
2859 if (from
->si_signo
== SIGBUS
&&
2860 (from
->si_code
== BUS_MCEERR_AR
|| from
->si_code
== BUS_MCEERR_AO
))
2861 err
|= __put_user(from
->si_addr_lsb
, &to
->si_addr_lsb
);
2864 if (from
->si_signo
== SIGSEGV
&& from
->si_code
== SEGV_BNDERR
) {
2865 err
|= __put_user(from
->si_lower
, &to
->si_lower
);
2866 err
|= __put_user(from
->si_upper
, &to
->si_upper
);
2870 if (from
->si_signo
== SIGSEGV
&& from
->si_code
== SEGV_PKUERR
)
2871 err
|= __put_user(from
->si_pkey
, &to
->si_pkey
);
2875 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2876 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2877 err
|= __put_user(from
->si_status
, &to
->si_status
);
2878 err
|= __put_user(from
->si_utime
, &to
->si_utime
);
2879 err
|= __put_user(from
->si_stime
, &to
->si_stime
);
2882 err
|= __put_user(from
->si_pid
, &to
->si_pid
);
2883 err
|= __put_user(from
->si_uid
, &to
->si_uid
);
2884 err
|= __put_user(from
->si_ptr
, &to
->si_ptr
);
2886 #ifdef __ARCH_SIGSYS
2888 err
|= __put_user(from
->si_call_addr
, &to
->si_call_addr
);
2889 err
|= __put_user(from
->si_syscall
, &to
->si_syscall
);
2890 err
|= __put_user(from
->si_arch
, &to
->si_arch
);
2900 * do_sigtimedwait - wait for queued signals specified in @which
2901 * @which: queued signals to wait for
2902 * @info: if non-null, the signal's siginfo is returned here
2903 * @ts: upper bound on process time suspension
2905 static int do_sigtimedwait(const sigset_t
*which
, siginfo_t
*info
,
2906 const struct timespec
*ts
)
2908 ktime_t
*to
= NULL
, timeout
= KTIME_MAX
;
2909 struct task_struct
*tsk
= current
;
2910 sigset_t mask
= *which
;
2914 if (!timespec_valid(ts
))
2916 timeout
= timespec_to_ktime(*ts
);
2921 * Invert the set of allowed signals to get those we want to block.
2923 sigdelsetmask(&mask
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
2926 spin_lock_irq(&tsk
->sighand
->siglock
);
2927 sig
= dequeue_signal(tsk
, &mask
, info
);
2928 if (!sig
&& timeout
) {
2930 * None ready, temporarily unblock those we're interested
2931 * while we are sleeping in so that we'll be awakened when
2932 * they arrive. Unblocking is always fine, we can avoid
2933 * set_current_blocked().
2935 tsk
->real_blocked
= tsk
->blocked
;
2936 sigandsets(&tsk
->blocked
, &tsk
->blocked
, &mask
);
2937 recalc_sigpending();
2938 spin_unlock_irq(&tsk
->sighand
->siglock
);
2940 __set_current_state(TASK_INTERRUPTIBLE
);
2941 ret
= freezable_schedule_hrtimeout_range(to
, tsk
->timer_slack_ns
,
2943 spin_lock_irq(&tsk
->sighand
->siglock
);
2944 __set_task_blocked(tsk
, &tsk
->real_blocked
);
2945 sigemptyset(&tsk
->real_blocked
);
2946 sig
= dequeue_signal(tsk
, &mask
, info
);
2948 spin_unlock_irq(&tsk
->sighand
->siglock
);
2952 return ret
? -EINTR
: -EAGAIN
;
2956 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
2958 * @uthese: queued signals to wait for
2959 * @uinfo: if non-null, the signal's siginfo is returned here
2960 * @uts: upper bound on process time suspension
2961 * @sigsetsize: size of sigset_t type
2963 SYSCALL_DEFINE4(rt_sigtimedwait
, const sigset_t __user
*, uthese
,
2964 siginfo_t __user
*, uinfo
, const struct timespec __user
*, uts
,
2972 /* XXX: Don't preclude handling different sized sigset_t's. */
2973 if (sigsetsize
!= sizeof(sigset_t
))
2976 if (copy_from_user(&these
, uthese
, sizeof(these
)))
2980 if (copy_from_user(&ts
, uts
, sizeof(ts
)))
2984 ret
= do_sigtimedwait(&these
, &info
, uts
? &ts
: NULL
);
2986 if (ret
> 0 && uinfo
) {
2987 if (copy_siginfo_to_user(uinfo
, &info
))
2994 #ifdef CONFIG_COMPAT
2995 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait
, compat_sigset_t __user
*, uthese
,
2996 struct compat_siginfo __user
*, uinfo
,
2997 struct compat_timespec __user
*, uts
, compat_size_t
, sigsetsize
)
2999 compat_sigset_t s32
;
3005 if (sigsetsize
!= sizeof(sigset_t
))
3008 if (copy_from_user(&s32
, uthese
, sizeof(compat_sigset_t
)))
3010 sigset_from_compat(&s
, &s32
);
3013 if (compat_get_timespec(&t
, uts
))
3017 ret
= do_sigtimedwait(&s
, &info
, uts
? &t
: NULL
);
3019 if (ret
> 0 && uinfo
) {
3020 if (copy_siginfo_to_user32(uinfo
, &info
))
3028 static inline void prepare_kill_siginfo(int sig
, struct siginfo
*info
)
3030 info
->si_signo
= sig
;
3032 info
->si_code
= SI_USER
;
3033 info
->si_pid
= task_tgid_vnr(current
);
3034 info
->si_uid
= from_kuid_munged(current_user_ns(), current_uid());
3038 * sys_kill - send a signal to a process
3039 * @pid: the PID of the process
3040 * @sig: signal to be sent
3042 SYSCALL_DEFINE2(kill
, pid_t
, pid
, int, sig
)
3044 struct siginfo info
;
3046 prepare_kill_siginfo(sig
, &info
);
3048 return kill_something_info(sig
, &info
, pid
);
3051 #ifdef CONFIG_PROC_FS
3053 * Verify that the signaler and signalee either are in the same pid namespace
3054 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3057 static bool access_pidfd_pidns(struct pid
*pid
)
3059 struct pid_namespace
*active
= task_active_pid_ns(current
);
3060 struct pid_namespace
*p
= ns_of_pid(pid
);
3073 static int copy_siginfo_from_user_any(siginfo_t
*kinfo
, siginfo_t __user
*info
)
3075 #ifdef CONFIG_COMPAT
3077 * Avoid hooking up compat syscalls and instead handle necessary
3078 * conversions here. Note, this is a stop-gap measure and should not be
3079 * considered a generic solution.
3081 if (in_compat_syscall())
3082 return copy_siginfo_from_user32(
3083 kinfo
, (struct compat_siginfo __user
*)info
);
3085 return copy_from_user(kinfo
, info
, sizeof(siginfo_t
));
3089 * sys_pidfd_send_signal - send a signal to a process through a task file
3091 * @pidfd: the file descriptor of the process
3092 * @sig: signal to be sent
3093 * @info: the signal info
3094 * @flags: future flags to be passed
3096 * The syscall currently only signals via PIDTYPE_PID which covers
3097 * kill(<positive-pid>, <signal>. It does not signal threads or process
3099 * In order to extend the syscall to threads and process groups the @flags
3100 * argument should be used. In essence, the @flags argument will determine
3101 * what is signaled and not the file descriptor itself. Put in other words,
3102 * grouping is a property of the flags argument not a property of the file
3105 * Return: 0 on success, negative errno on failure
3107 SYSCALL_DEFINE4(pidfd_send_signal
, int, pidfd
, int, sig
,
3108 siginfo_t __user
*, info
, unsigned int, flags
)
3115 /* Enforce flags be set to 0 until we add an extension. */
3119 f
= fdget_raw(pidfd
);
3123 /* Is this a pidfd? */
3124 pid
= tgid_pidfd_to_pid(f
.file
);
3131 if (!access_pidfd_pidns(pid
))
3135 ret
= copy_siginfo_from_user_any(&kinfo
, info
);
3140 if (unlikely(sig
!= kinfo
.si_signo
))
3143 if ((task_pid(current
) != pid
) &&
3144 (kinfo
.si_code
>= 0 || kinfo
.si_code
== SI_TKILL
)) {
3145 /* Only allow sending arbitrary signals to yourself. */
3147 if (kinfo
.si_code
!= SI_USER
)
3150 /* Turn this into a regular kill signal. */
3151 prepare_kill_siginfo(sig
, &kinfo
);
3154 prepare_kill_siginfo(sig
, &kinfo
);
3157 ret
= kill_pid_info(sig
, &kinfo
, pid
);
3163 #endif /* CONFIG_PROC_FS */
3166 do_send_specific(pid_t tgid
, pid_t pid
, int sig
, struct siginfo
*info
)
3168 struct task_struct
*p
;
3172 p
= find_task_by_vpid(pid
);
3173 if (p
&& (tgid
<= 0 || task_tgid_vnr(p
) == tgid
)) {
3174 error
= check_kill_permission(sig
, info
, p
);
3176 * The null signal is a permissions and process existence
3177 * probe. No signal is actually delivered.
3179 if (!error
&& sig
) {
3180 error
= do_send_sig_info(sig
, info
, p
, false);
3182 * If lock_task_sighand() failed we pretend the task
3183 * dies after receiving the signal. The window is tiny,
3184 * and the signal is private anyway.
3186 if (unlikely(error
== -ESRCH
))
3195 static int do_tkill(pid_t tgid
, pid_t pid
, int sig
)
3197 struct siginfo info
= {};
3199 info
.si_signo
= sig
;
3201 info
.si_code
= SI_TKILL
;
3202 info
.si_pid
= task_tgid_vnr(current
);
3203 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
3205 return do_send_specific(tgid
, pid
, sig
, &info
);
3209 * sys_tgkill - send signal to one specific thread
3210 * @tgid: the thread group ID of the thread
3211 * @pid: the PID of the thread
3212 * @sig: signal to be sent
3214 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3215 * exists but it's not belonging to the target process anymore. This
3216 * method solves the problem of threads exiting and PIDs getting reused.
3218 SYSCALL_DEFINE3(tgkill
, pid_t
, tgid
, pid_t
, pid
, int, sig
)
3220 /* This is only valid for single tasks */
3221 if (pid
<= 0 || tgid
<= 0)
3224 return do_tkill(tgid
, pid
, sig
);
3228 * sys_tkill - send signal to one specific task
3229 * @pid: the PID of the task
3230 * @sig: signal to be sent
3232 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3234 SYSCALL_DEFINE2(tkill
, pid_t
, pid
, int, sig
)
3236 /* This is only valid for single tasks */
3240 return do_tkill(0, pid
, sig
);
3243 static int do_rt_sigqueueinfo(pid_t pid
, int sig
, siginfo_t
*info
)
3245 /* Not even root can pretend to send signals from the kernel.
3246 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3248 if ((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
) &&
3249 (task_pid_vnr(current
) != pid
))
3252 info
->si_signo
= sig
;
3254 /* POSIX.1b doesn't mention process groups. */
3255 return kill_proc_info(sig
, info
, pid
);
3259 * sys_rt_sigqueueinfo - send signal information to a signal
3260 * @pid: the PID of the thread
3261 * @sig: signal to be sent
3262 * @uinfo: signal info to be sent
3264 SYSCALL_DEFINE3(rt_sigqueueinfo
, pid_t
, pid
, int, sig
,
3265 siginfo_t __user
*, uinfo
)
3268 if (copy_from_user(&info
, uinfo
, sizeof(siginfo_t
)))
3270 return do_rt_sigqueueinfo(pid
, sig
, &info
);
3273 #ifdef CONFIG_COMPAT
3274 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo
,
3277 struct compat_siginfo __user
*, uinfo
)
3279 siginfo_t info
= {};
3280 int ret
= copy_siginfo_from_user32(&info
, uinfo
);
3283 return do_rt_sigqueueinfo(pid
, sig
, &info
);
3287 static int do_rt_tgsigqueueinfo(pid_t tgid
, pid_t pid
, int sig
, siginfo_t
*info
)
3289 /* This is only valid for single tasks */
3290 if (pid
<= 0 || tgid
<= 0)
3293 /* Not even root can pretend to send signals from the kernel.
3294 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3296 if ((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
) &&
3297 (task_pid_vnr(current
) != pid
))
3300 info
->si_signo
= sig
;
3302 return do_send_specific(tgid
, pid
, sig
, info
);
3305 SYSCALL_DEFINE4(rt_tgsigqueueinfo
, pid_t
, tgid
, pid_t
, pid
, int, sig
,
3306 siginfo_t __user
*, uinfo
)
3310 if (copy_from_user(&info
, uinfo
, sizeof(siginfo_t
)))
3313 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
3316 #ifdef CONFIG_COMPAT
3317 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo
,
3321 struct compat_siginfo __user
*, uinfo
)
3323 siginfo_t info
= {};
3325 if (copy_siginfo_from_user32(&info
, uinfo
))
3327 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
3332 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3334 void kernel_sigaction(int sig
, __sighandler_t action
)
3336 spin_lock_irq(¤t
->sighand
->siglock
);
3337 current
->sighand
->action
[sig
- 1].sa
.sa_handler
= action
;
3338 if (action
== SIG_IGN
) {
3342 sigaddset(&mask
, sig
);
3344 flush_sigqueue_mask(&mask
, ¤t
->signal
->shared_pending
);
3345 flush_sigqueue_mask(&mask
, ¤t
->pending
);
3346 recalc_sigpending();
3348 spin_unlock_irq(¤t
->sighand
->siglock
);
3350 EXPORT_SYMBOL(kernel_sigaction
);
3352 void __weak
sigaction_compat_abi(struct k_sigaction
*act
,
3353 struct k_sigaction
*oact
)
3357 int do_sigaction(int sig
, struct k_sigaction
*act
, struct k_sigaction
*oact
)
3359 struct task_struct
*p
= current
, *t
;
3360 struct k_sigaction
*k
;
3363 if (!valid_signal(sig
) || sig
< 1 || (act
&& sig_kernel_only(sig
)))
3366 k
= &p
->sighand
->action
[sig
-1];
3368 spin_lock_irq(&p
->sighand
->siglock
);
3372 sigaction_compat_abi(act
, oact
);
3375 sigdelsetmask(&act
->sa
.sa_mask
,
3376 sigmask(SIGKILL
) | sigmask(SIGSTOP
));
3380 * "Setting a signal action to SIG_IGN for a signal that is
3381 * pending shall cause the pending signal to be discarded,
3382 * whether or not it is blocked."
3384 * "Setting a signal action to SIG_DFL for a signal that is
3385 * pending and whose default action is to ignore the signal
3386 * (for example, SIGCHLD), shall cause the pending signal to
3387 * be discarded, whether or not it is blocked"
3389 if (sig_handler_ignored(sig_handler(p
, sig
), sig
)) {
3391 sigaddset(&mask
, sig
);
3392 flush_sigqueue_mask(&mask
, &p
->signal
->shared_pending
);
3393 for_each_thread(p
, t
)
3394 flush_sigqueue_mask(&mask
, &t
->pending
);
3398 spin_unlock_irq(&p
->sighand
->siglock
);
3403 do_sigaltstack (const stack_t
*ss
, stack_t
*oss
, unsigned long sp
,
3406 struct task_struct
*t
= current
;
3409 memset(oss
, 0, sizeof(stack_t
));
3410 oss
->ss_sp
= (void __user
*) t
->sas_ss_sp
;
3411 oss
->ss_size
= t
->sas_ss_size
;
3412 oss
->ss_flags
= sas_ss_flags(sp
) |
3413 (current
->sas_ss_flags
& SS_FLAG_BITS
);
3417 void __user
*ss_sp
= ss
->ss_sp
;
3418 size_t ss_size
= ss
->ss_size
;
3419 unsigned ss_flags
= ss
->ss_flags
;
3422 if (unlikely(on_sig_stack(sp
)))
3425 ss_mode
= ss_flags
& ~SS_FLAG_BITS
;
3426 if (unlikely(ss_mode
!= SS_DISABLE
&& ss_mode
!= SS_ONSTACK
&&
3430 if (ss_mode
== SS_DISABLE
) {
3434 if (unlikely(ss_size
< min_ss_size
))
3438 t
->sas_ss_sp
= (unsigned long) ss_sp
;
3439 t
->sas_ss_size
= ss_size
;
3440 t
->sas_ss_flags
= ss_flags
;
3445 SYSCALL_DEFINE2(sigaltstack
,const stack_t __user
*,uss
, stack_t __user
*,uoss
)
3449 if (uss
&& copy_from_user(&new, uss
, sizeof(stack_t
)))
3451 err
= do_sigaltstack(uss
? &new : NULL
, uoss
? &old
: NULL
,
3452 current_user_stack_pointer(),
3454 if (!err
&& uoss
&& copy_to_user(uoss
, &old
, sizeof(stack_t
)))
3459 int restore_altstack(const stack_t __user
*uss
)
3462 if (copy_from_user(&new, uss
, sizeof(stack_t
)))
3464 (void)do_sigaltstack(&new, NULL
, current_user_stack_pointer(),
3466 /* squash all but EFAULT for now */
3470 int __save_altstack(stack_t __user
*uss
, unsigned long sp
)
3472 struct task_struct
*t
= current
;
3473 int err
= __put_user((void __user
*)t
->sas_ss_sp
, &uss
->ss_sp
) |
3474 __put_user(t
->sas_ss_flags
, &uss
->ss_flags
) |
3475 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
3478 if (t
->sas_ss_flags
& SS_AUTODISARM
)
3483 #ifdef CONFIG_COMPAT
3484 COMPAT_SYSCALL_DEFINE2(sigaltstack
,
3485 const compat_stack_t __user
*, uss_ptr
,
3486 compat_stack_t __user
*, uoss_ptr
)
3492 compat_stack_t uss32
;
3493 if (copy_from_user(&uss32
, uss_ptr
, sizeof(compat_stack_t
)))
3495 uss
.ss_sp
= compat_ptr(uss32
.ss_sp
);
3496 uss
.ss_flags
= uss32
.ss_flags
;
3497 uss
.ss_size
= uss32
.ss_size
;
3499 ret
= do_sigaltstack(uss_ptr
? &uss
: NULL
, &uoss
,
3500 compat_user_stack_pointer(),
3501 COMPAT_MINSIGSTKSZ
);
3502 if (ret
>= 0 && uoss_ptr
) {
3504 memset(&old
, 0, sizeof(old
));
3505 old
.ss_sp
= ptr_to_compat(uoss
.ss_sp
);
3506 old
.ss_flags
= uoss
.ss_flags
;
3507 old
.ss_size
= uoss
.ss_size
;
3508 if (copy_to_user(uoss_ptr
, &old
, sizeof(compat_stack_t
)))
3514 int compat_restore_altstack(const compat_stack_t __user
*uss
)
3516 int err
= compat_sys_sigaltstack(uss
, NULL
);
3517 /* squash all but -EFAULT for now */
3518 return err
== -EFAULT
? err
: 0;
3521 int __compat_save_altstack(compat_stack_t __user
*uss
, unsigned long sp
)
3524 struct task_struct
*t
= current
;
3525 err
= __put_user(ptr_to_compat((void __user
*)t
->sas_ss_sp
),
3527 __put_user(t
->sas_ss_flags
, &uss
->ss_flags
) |
3528 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
3531 if (t
->sas_ss_flags
& SS_AUTODISARM
)
3537 #ifdef __ARCH_WANT_SYS_SIGPENDING
3540 * sys_sigpending - examine pending signals
3541 * @set: where mask of pending signal is returned
3543 SYSCALL_DEFINE1(sigpending
, old_sigset_t __user
*, set
)
3545 return sys_rt_sigpending((sigset_t __user
*)set
, sizeof(old_sigset_t
));
3548 #ifdef CONFIG_COMPAT
3549 COMPAT_SYSCALL_DEFINE1(sigpending
, compat_old_sigset_t __user
*, set32
)
3553 int err
= do_sigpending(&set
, sizeof(set
.sig
[0]));
3555 err
= put_user(set
.sig
[0], set32
);
3558 return sys_rt_sigpending((sigset_t __user
*)set32
, sizeof(*set32
));
3565 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
3567 * sys_sigprocmask - examine and change blocked signals
3568 * @how: whether to add, remove, or set signals
3569 * @nset: signals to add or remove (if non-null)
3570 * @oset: previous value of signal mask if non-null
3572 * Some platforms have their own version with special arguments;
3573 * others support only sys_rt_sigprocmask.
3576 SYSCALL_DEFINE3(sigprocmask
, int, how
, old_sigset_t __user
*, nset
,
3577 old_sigset_t __user
*, oset
)
3579 old_sigset_t old_set
, new_set
;
3580 sigset_t new_blocked
;
3582 old_set
= current
->blocked
.sig
[0];
3585 if (copy_from_user(&new_set
, nset
, sizeof(*nset
)))
3588 new_blocked
= current
->blocked
;
3592 sigaddsetmask(&new_blocked
, new_set
);
3595 sigdelsetmask(&new_blocked
, new_set
);
3598 new_blocked
.sig
[0] = new_set
;
3604 set_current_blocked(&new_blocked
);
3608 if (copy_to_user(oset
, &old_set
, sizeof(*oset
)))
3614 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
3616 #ifndef CONFIG_ODD_RT_SIGACTION
3618 * sys_rt_sigaction - alter an action taken by a process
3619 * @sig: signal to be sent
3620 * @act: new sigaction
3621 * @oact: used to save the previous sigaction
3622 * @sigsetsize: size of sigset_t type
3624 SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
3625 const struct sigaction __user
*, act
,
3626 struct sigaction __user
*, oact
,
3629 struct k_sigaction new_sa
, old_sa
;
3632 /* XXX: Don't preclude handling different sized sigset_t's. */
3633 if (sigsetsize
!= sizeof(sigset_t
))
3637 if (copy_from_user(&new_sa
.sa
, act
, sizeof(new_sa
.sa
)))
3641 ret
= do_sigaction(sig
, act
? &new_sa
: NULL
, oact
? &old_sa
: NULL
);
3644 if (copy_to_user(oact
, &old_sa
.sa
, sizeof(old_sa
.sa
)))
3650 #ifdef CONFIG_COMPAT
3651 COMPAT_SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
3652 const struct compat_sigaction __user
*, act
,
3653 struct compat_sigaction __user
*, oact
,
3654 compat_size_t
, sigsetsize
)
3656 struct k_sigaction new_ka
, old_ka
;
3657 compat_sigset_t mask
;
3658 #ifdef __ARCH_HAS_SA_RESTORER
3659 compat_uptr_t restorer
;
3663 /* XXX: Don't preclude handling different sized sigset_t's. */
3664 if (sigsetsize
!= sizeof(compat_sigset_t
))
3668 compat_uptr_t handler
;
3669 ret
= get_user(handler
, &act
->sa_handler
);
3670 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
3671 #ifdef __ARCH_HAS_SA_RESTORER
3672 ret
|= get_user(restorer
, &act
->sa_restorer
);
3673 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
3675 ret
|= copy_from_user(&mask
, &act
->sa_mask
, sizeof(mask
));
3676 ret
|= get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
);
3679 sigset_from_compat(&new_ka
.sa
.sa_mask
, &mask
);
3682 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
3684 sigset_to_compat(&mask
, &old_ka
.sa
.sa_mask
);
3685 ret
= put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
3687 ret
|= copy_to_user(&oact
->sa_mask
, &mask
, sizeof(mask
));
3688 ret
|= put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
);
3689 #ifdef __ARCH_HAS_SA_RESTORER
3690 ret
|= put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
3691 &oact
->sa_restorer
);
3697 #endif /* !CONFIG_ODD_RT_SIGACTION */
3699 #ifdef CONFIG_OLD_SIGACTION
3700 SYSCALL_DEFINE3(sigaction
, int, sig
,
3701 const struct old_sigaction __user
*, act
,
3702 struct old_sigaction __user
*, oact
)
3704 struct k_sigaction new_ka
, old_ka
;
3709 if (!access_ok(VERIFY_READ
, act
, sizeof(*act
)) ||
3710 __get_user(new_ka
.sa
.sa_handler
, &act
->sa_handler
) ||
3711 __get_user(new_ka
.sa
.sa_restorer
, &act
->sa_restorer
) ||
3712 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
3713 __get_user(mask
, &act
->sa_mask
))
3715 #ifdef __ARCH_HAS_KA_RESTORER
3716 new_ka
.ka_restorer
= NULL
;
3718 siginitset(&new_ka
.sa
.sa_mask
, mask
);
3721 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
3724 if (!access_ok(VERIFY_WRITE
, oact
, sizeof(*oact
)) ||
3725 __put_user(old_ka
.sa
.sa_handler
, &oact
->sa_handler
) ||
3726 __put_user(old_ka
.sa
.sa_restorer
, &oact
->sa_restorer
) ||
3727 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
3728 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
3735 #ifdef CONFIG_COMPAT_OLD_SIGACTION
3736 COMPAT_SYSCALL_DEFINE3(sigaction
, int, sig
,
3737 const struct compat_old_sigaction __user
*, act
,
3738 struct compat_old_sigaction __user
*, oact
)
3740 struct k_sigaction new_ka
, old_ka
;
3742 compat_old_sigset_t mask
;
3743 compat_uptr_t handler
, restorer
;
3746 if (!access_ok(VERIFY_READ
, act
, sizeof(*act
)) ||
3747 __get_user(handler
, &act
->sa_handler
) ||
3748 __get_user(restorer
, &act
->sa_restorer
) ||
3749 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
3750 __get_user(mask
, &act
->sa_mask
))
3753 #ifdef __ARCH_HAS_KA_RESTORER
3754 new_ka
.ka_restorer
= NULL
;
3756 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
3757 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
3758 siginitset(&new_ka
.sa
.sa_mask
, mask
);
3761 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
3764 if (!access_ok(VERIFY_WRITE
, oact
, sizeof(*oact
)) ||
3765 __put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
3766 &oact
->sa_handler
) ||
3767 __put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
3768 &oact
->sa_restorer
) ||
3769 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
3770 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
3777 #ifdef CONFIG_SGETMASK_SYSCALL
3780 * For backwards compatibility. Functionality superseded by sigprocmask.
3782 SYSCALL_DEFINE0(sgetmask
)
3785 return current
->blocked
.sig
[0];
3788 SYSCALL_DEFINE1(ssetmask
, int, newmask
)
3790 int old
= current
->blocked
.sig
[0];
3793 siginitset(&newset
, newmask
);
3794 set_current_blocked(&newset
);
3798 #endif /* CONFIG_SGETMASK_SYSCALL */
3800 #ifdef __ARCH_WANT_SYS_SIGNAL
3802 * For backwards compatibility. Functionality superseded by sigaction.
3804 SYSCALL_DEFINE2(signal
, int, sig
, __sighandler_t
, handler
)
3806 struct k_sigaction new_sa
, old_sa
;
3809 new_sa
.sa
.sa_handler
= handler
;
3810 new_sa
.sa
.sa_flags
= SA_ONESHOT
| SA_NOMASK
;
3811 sigemptyset(&new_sa
.sa
.sa_mask
);
3813 ret
= do_sigaction(sig
, &new_sa
, &old_sa
);
3815 return ret
? ret
: (unsigned long)old_sa
.sa
.sa_handler
;
3817 #endif /* __ARCH_WANT_SYS_SIGNAL */
3819 #ifdef __ARCH_WANT_SYS_PAUSE
3821 SYSCALL_DEFINE0(pause
)
3823 while (!signal_pending(current
)) {
3824 __set_current_state(TASK_INTERRUPTIBLE
);
3827 return -ERESTARTNOHAND
;
3832 static int sigsuspend(sigset_t
*set
)
3834 current
->saved_sigmask
= current
->blocked
;
3835 set_current_blocked(set
);
3837 while (!signal_pending(current
)) {
3838 __set_current_state(TASK_INTERRUPTIBLE
);
3841 set_restore_sigmask();
3842 return -ERESTARTNOHAND
;
3846 * sys_rt_sigsuspend - replace the signal mask for a value with the
3847 * @unewset value until a signal is received
3848 * @unewset: new signal mask value
3849 * @sigsetsize: size of sigset_t type
3851 SYSCALL_DEFINE2(rt_sigsuspend
, sigset_t __user
*, unewset
, size_t, sigsetsize
)
3855 /* XXX: Don't preclude handling different sized sigset_t's. */
3856 if (sigsetsize
!= sizeof(sigset_t
))
3859 if (copy_from_user(&newset
, unewset
, sizeof(newset
)))
3861 return sigsuspend(&newset
);
3864 #ifdef CONFIG_COMPAT
3865 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend
, compat_sigset_t __user
*, unewset
, compat_size_t
, sigsetsize
)
3869 compat_sigset_t newset32
;
3871 /* XXX: Don't preclude handling different sized sigset_t's. */
3872 if (sigsetsize
!= sizeof(sigset_t
))
3875 if (copy_from_user(&newset32
, unewset
, sizeof(compat_sigset_t
)))
3877 sigset_from_compat(&newset
, &newset32
);
3878 return sigsuspend(&newset
);
3880 /* on little-endian bitmaps don't care about granularity */
3881 return sys_rt_sigsuspend((sigset_t __user
*)unewset
, sigsetsize
);
3886 #ifdef CONFIG_OLD_SIGSUSPEND
3887 SYSCALL_DEFINE1(sigsuspend
, old_sigset_t
, mask
)
3890 siginitset(&blocked
, mask
);
3891 return sigsuspend(&blocked
);
3894 #ifdef CONFIG_OLD_SIGSUSPEND3
3895 SYSCALL_DEFINE3(sigsuspend
, int, unused1
, int, unused2
, old_sigset_t
, mask
)
3898 siginitset(&blocked
, mask
);
3899 return sigsuspend(&blocked
);
3903 __weak
const char *arch_vma_name(struct vm_area_struct
*vma
)
3908 void __init
signals_init(void)
3910 /* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */
3911 BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE
3912 != offsetof(struct siginfo
, _sifields
._pad
));
3914 sigqueue_cachep
= KMEM_CACHE(sigqueue
, SLAB_PANIC
);
3917 #ifdef CONFIG_KGDB_KDB
3918 #include <linux/kdb.h>
3920 * kdb_send_sig_info - Allows kdb to send signals without exposing
3921 * signal internals. This function checks if the required locks are
3922 * available before calling the main signal code, to avoid kdb
3926 kdb_send_sig_info(struct task_struct
*t
, struct siginfo
*info
)
3928 static struct task_struct
*kdb_prev_t
;
3930 if (!spin_trylock(&t
->sighand
->siglock
)) {
3931 kdb_printf("Can't do kill command now.\n"
3932 "The sigmask lock is held somewhere else in "
3933 "kernel, try again later\n");
3936 spin_unlock(&t
->sighand
->siglock
);
3937 new_t
= kdb_prev_t
!= t
;
3939 if (t
->state
!= TASK_RUNNING
&& new_t
) {
3940 kdb_printf("Process is not RUNNING, sending a signal from "
3941 "kdb risks deadlock\n"
3942 "on the run queue locks. "
3943 "The signal has _not_ been sent.\n"
3944 "Reissue the kill command if you want to risk "
3948 sig
= info
->si_signo
;
3949 if (send_sig_info(sig
, info
, t
))
3950 kdb_printf("Fail to deliver Signal %d to process %d.\n",
3953 kdb_printf("Signal %d is sent to process %d.\n", sig
, t
->pid
);
3955 #endif /* CONFIG_KGDB_KDB */