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/livepatch.h>
46 #include <linux/cgroup.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 inline bool 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 bool sig_task_ignored(struct task_struct
*t
, int sig
, bool force
)
82 handler
= sig_handler(t
, sig
);
84 /* SIGKILL and SIGSTOP may not be sent to the global init */
85 if (unlikely(is_global_init(t
) && sig_kernel_only(sig
)))
88 if (unlikely(t
->signal
->flags
& SIGNAL_UNKILLABLE
) &&
89 handler
== SIG_DFL
&& !(force
&& sig_kernel_only(sig
)))
92 return sig_handler_ignored(handler
, sig
);
95 static bool sig_ignored(struct task_struct
*t
, int sig
, bool force
)
98 * Blocked signals are never ignored, since the
99 * signal handler may change by the time it is
102 if (sigismember(&t
->blocked
, sig
) || sigismember(&t
->real_blocked
, sig
))
106 * Tracers may want to know about even ignored signal unless it
107 * is SIGKILL which can't be reported anyway but can be ignored
108 * by SIGNAL_UNKILLABLE task.
110 if (t
->ptrace
&& sig
!= SIGKILL
)
113 return sig_task_ignored(t
, sig
, force
);
117 * Re-calculate pending state from the set of locally pending
118 * signals, globally pending signals, and blocked signals.
120 static inline bool has_pending_signals(sigset_t
*signal
, sigset_t
*blocked
)
125 switch (_NSIG_WORDS
) {
127 for (i
= _NSIG_WORDS
, ready
= 0; --i
>= 0 ;)
128 ready
|= signal
->sig
[i
] &~ blocked
->sig
[i
];
131 case 4: ready
= signal
->sig
[3] &~ blocked
->sig
[3];
132 ready
|= signal
->sig
[2] &~ blocked
->sig
[2];
133 ready
|= signal
->sig
[1] &~ blocked
->sig
[1];
134 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
137 case 2: ready
= signal
->sig
[1] &~ blocked
->sig
[1];
138 ready
|= signal
->sig
[0] &~ blocked
->sig
[0];
141 case 1: ready
= signal
->sig
[0] &~ blocked
->sig
[0];
146 #define PENDING(p,b) has_pending_signals(&(p)->signal, (b))
148 static bool recalc_sigpending_tsk(struct task_struct
*t
)
150 if ((t
->jobctl
& (JOBCTL_PENDING_MASK
| JOBCTL_TRAP_FREEZE
)) ||
151 PENDING(&t
->pending
, &t
->blocked
) ||
152 PENDING(&t
->signal
->shared_pending
, &t
->blocked
) ||
153 cgroup_task_frozen(t
)) {
154 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
159 * We must never clear the flag in another thread, or in current
160 * when it's possible the current syscall is returning -ERESTART*.
161 * So we don't clear it here, and only callers who know they should do.
167 * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up.
168 * This is superfluous when called on current, the wakeup is a harmless no-op.
170 void recalc_sigpending_and_wake(struct task_struct
*t
)
172 if (recalc_sigpending_tsk(t
))
173 signal_wake_up(t
, 0);
176 void recalc_sigpending(void)
178 if (!recalc_sigpending_tsk(current
) && !freezing(current
) &&
179 !klp_patch_pending(current
))
180 clear_thread_flag(TIF_SIGPENDING
);
183 EXPORT_SYMBOL(recalc_sigpending
);
185 void calculate_sigpending(void)
187 /* Have any signals or users of TIF_SIGPENDING been delayed
190 spin_lock_irq(¤t
->sighand
->siglock
);
191 set_tsk_thread_flag(current
, TIF_SIGPENDING
);
193 spin_unlock_irq(¤t
->sighand
->siglock
);
196 /* Given the mask, find the first available signal that should be serviced. */
198 #define SYNCHRONOUS_MASK \
199 (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
200 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))
202 int next_signal(struct sigpending
*pending
, sigset_t
*mask
)
204 unsigned long i
, *s
, *m
, x
;
207 s
= pending
->signal
.sig
;
211 * Handle the first word specially: it contains the
212 * synchronous signals that need to be dequeued first.
216 if (x
& SYNCHRONOUS_MASK
)
217 x
&= SYNCHRONOUS_MASK
;
222 switch (_NSIG_WORDS
) {
224 for (i
= 1; i
< _NSIG_WORDS
; ++i
) {
228 sig
= ffz(~x
) + i
*_NSIG_BPW
+ 1;
237 sig
= ffz(~x
) + _NSIG_BPW
+ 1;
248 static inline void print_dropped_signal(int sig
)
250 static DEFINE_RATELIMIT_STATE(ratelimit_state
, 5 * HZ
, 10);
252 if (!print_fatal_signals
)
255 if (!__ratelimit(&ratelimit_state
))
258 pr_info("%s/%d: reached RLIMIT_SIGPENDING, dropped signal %d\n",
259 current
->comm
, current
->pid
, sig
);
263 * task_set_jobctl_pending - set jobctl pending bits
265 * @mask: pending bits to set
267 * Clear @mask from @task->jobctl. @mask must be subset of
268 * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
269 * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
270 * cleared. If @task is already being killed or exiting, this function
274 * Must be called with @task->sighand->siglock held.
277 * %true if @mask is set, %false if made noop because @task was dying.
279 bool task_set_jobctl_pending(struct task_struct
*task
, unsigned long mask
)
281 BUG_ON(mask
& ~(JOBCTL_PENDING_MASK
| JOBCTL_STOP_CONSUME
|
282 JOBCTL_STOP_SIGMASK
| JOBCTL_TRAPPING
));
283 BUG_ON((mask
& JOBCTL_TRAPPING
) && !(mask
& JOBCTL_PENDING_MASK
));
285 if (unlikely(fatal_signal_pending(task
) || (task
->flags
& PF_EXITING
)))
288 if (mask
& JOBCTL_STOP_SIGMASK
)
289 task
->jobctl
&= ~JOBCTL_STOP_SIGMASK
;
291 task
->jobctl
|= mask
;
296 * task_clear_jobctl_trapping - clear jobctl trapping bit
299 * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
300 * Clear it and wake up the ptracer. Note that we don't need any further
301 * locking. @task->siglock guarantees that @task->parent points to the
305 * Must be called with @task->sighand->siglock held.
307 void task_clear_jobctl_trapping(struct task_struct
*task
)
309 if (unlikely(task
->jobctl
& JOBCTL_TRAPPING
)) {
310 task
->jobctl
&= ~JOBCTL_TRAPPING
;
311 smp_mb(); /* advised by wake_up_bit() */
312 wake_up_bit(&task
->jobctl
, JOBCTL_TRAPPING_BIT
);
317 * task_clear_jobctl_pending - clear jobctl pending bits
319 * @mask: pending bits to clear
321 * Clear @mask from @task->jobctl. @mask must be subset of
322 * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
323 * STOP bits are cleared together.
325 * If clearing of @mask leaves no stop or trap pending, this function calls
326 * task_clear_jobctl_trapping().
329 * Must be called with @task->sighand->siglock held.
331 void task_clear_jobctl_pending(struct task_struct
*task
, unsigned long mask
)
333 BUG_ON(mask
& ~JOBCTL_PENDING_MASK
);
335 if (mask
& JOBCTL_STOP_PENDING
)
336 mask
|= JOBCTL_STOP_CONSUME
| JOBCTL_STOP_DEQUEUED
;
338 task
->jobctl
&= ~mask
;
340 if (!(task
->jobctl
& JOBCTL_PENDING_MASK
))
341 task_clear_jobctl_trapping(task
);
345 * task_participate_group_stop - participate in a group stop
346 * @task: task participating in a group stop
348 * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
349 * Group stop states are cleared and the group stop count is consumed if
350 * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
351 * stop, the appropriate %SIGNAL_* flags are set.
354 * Must be called with @task->sighand->siglock held.
357 * %true if group stop completion should be notified to the parent, %false
360 static bool task_participate_group_stop(struct task_struct
*task
)
362 struct signal_struct
*sig
= task
->signal
;
363 bool consume
= task
->jobctl
& JOBCTL_STOP_CONSUME
;
365 WARN_ON_ONCE(!(task
->jobctl
& JOBCTL_STOP_PENDING
));
367 task_clear_jobctl_pending(task
, JOBCTL_STOP_PENDING
);
372 if (!WARN_ON_ONCE(sig
->group_stop_count
== 0))
373 sig
->group_stop_count
--;
376 * Tell the caller to notify completion iff we are entering into a
377 * fresh group stop. Read comment in do_signal_stop() for details.
379 if (!sig
->group_stop_count
&& !(sig
->flags
& SIGNAL_STOP_STOPPED
)) {
380 signal_set_stop_flags(sig
, SIGNAL_STOP_STOPPED
);
386 void task_join_group_stop(struct task_struct
*task
)
388 /* Have the new thread join an on-going signal group stop */
389 unsigned long jobctl
= current
->jobctl
;
390 if (jobctl
& JOBCTL_STOP_PENDING
) {
391 struct signal_struct
*sig
= current
->signal
;
392 unsigned long signr
= jobctl
& JOBCTL_STOP_SIGMASK
;
393 unsigned long gstop
= JOBCTL_STOP_PENDING
| JOBCTL_STOP_CONSUME
;
394 if (task_set_jobctl_pending(task
, signr
| gstop
)) {
395 sig
->group_stop_count
++;
401 * allocate a new signal queue record
402 * - this may be called without locks if and only if t == current, otherwise an
403 * appropriate lock must be held to stop the target task from exiting
405 static struct sigqueue
*
406 __sigqueue_alloc(int sig
, struct task_struct
*t
, gfp_t flags
, int override_rlimit
)
408 struct sigqueue
*q
= NULL
;
409 struct user_struct
*user
;
412 * Protect access to @t credentials. This can go away when all
413 * callers hold rcu read lock.
416 user
= get_uid(__task_cred(t
)->user
);
417 atomic_inc(&user
->sigpending
);
420 if (override_rlimit
||
421 atomic_read(&user
->sigpending
) <=
422 task_rlimit(t
, RLIMIT_SIGPENDING
)) {
423 q
= kmem_cache_alloc(sigqueue_cachep
, flags
);
425 print_dropped_signal(sig
);
428 if (unlikely(q
== NULL
)) {
429 atomic_dec(&user
->sigpending
);
432 INIT_LIST_HEAD(&q
->list
);
440 static void __sigqueue_free(struct sigqueue
*q
)
442 if (q
->flags
& SIGQUEUE_PREALLOC
)
444 atomic_dec(&q
->user
->sigpending
);
446 kmem_cache_free(sigqueue_cachep
, q
);
449 void flush_sigqueue(struct sigpending
*queue
)
453 sigemptyset(&queue
->signal
);
454 while (!list_empty(&queue
->list
)) {
455 q
= list_entry(queue
->list
.next
, struct sigqueue
, list
);
456 list_del_init(&q
->list
);
462 * Flush all pending signals for this kthread.
464 void flush_signals(struct task_struct
*t
)
468 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
469 clear_tsk_thread_flag(t
, TIF_SIGPENDING
);
470 flush_sigqueue(&t
->pending
);
471 flush_sigqueue(&t
->signal
->shared_pending
);
472 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
474 EXPORT_SYMBOL(flush_signals
);
476 #ifdef CONFIG_POSIX_TIMERS
477 static void __flush_itimer_signals(struct sigpending
*pending
)
479 sigset_t signal
, retain
;
480 struct sigqueue
*q
, *n
;
482 signal
= pending
->signal
;
483 sigemptyset(&retain
);
485 list_for_each_entry_safe(q
, n
, &pending
->list
, list
) {
486 int sig
= q
->info
.si_signo
;
488 if (likely(q
->info
.si_code
!= SI_TIMER
)) {
489 sigaddset(&retain
, sig
);
491 sigdelset(&signal
, sig
);
492 list_del_init(&q
->list
);
497 sigorsets(&pending
->signal
, &signal
, &retain
);
500 void flush_itimer_signals(void)
502 struct task_struct
*tsk
= current
;
505 spin_lock_irqsave(&tsk
->sighand
->siglock
, flags
);
506 __flush_itimer_signals(&tsk
->pending
);
507 __flush_itimer_signals(&tsk
->signal
->shared_pending
);
508 spin_unlock_irqrestore(&tsk
->sighand
->siglock
, flags
);
512 void ignore_signals(struct task_struct
*t
)
516 for (i
= 0; i
< _NSIG
; ++i
)
517 t
->sighand
->action
[i
].sa
.sa_handler
= SIG_IGN
;
523 * Flush all handlers for a task.
527 flush_signal_handlers(struct task_struct
*t
, int force_default
)
530 struct k_sigaction
*ka
= &t
->sighand
->action
[0];
531 for (i
= _NSIG
; i
!= 0 ; i
--) {
532 if (force_default
|| ka
->sa
.sa_handler
!= SIG_IGN
)
533 ka
->sa
.sa_handler
= SIG_DFL
;
535 #ifdef __ARCH_HAS_SA_RESTORER
536 ka
->sa
.sa_restorer
= NULL
;
538 sigemptyset(&ka
->sa
.sa_mask
);
543 bool unhandled_signal(struct task_struct
*tsk
, int sig
)
545 void __user
*handler
= tsk
->sighand
->action
[sig
-1].sa
.sa_handler
;
546 if (is_global_init(tsk
))
549 if (handler
!= SIG_IGN
&& handler
!= SIG_DFL
)
552 /* if ptraced, let the tracer determine */
556 static void collect_signal(int sig
, struct sigpending
*list
, kernel_siginfo_t
*info
,
559 struct sigqueue
*q
, *first
= NULL
;
562 * Collect the siginfo appropriate to this signal. Check if
563 * there is another siginfo for the same signal.
565 list_for_each_entry(q
, &list
->list
, list
) {
566 if (q
->info
.si_signo
== sig
) {
573 sigdelset(&list
->signal
, sig
);
577 list_del_init(&first
->list
);
578 copy_siginfo(info
, &first
->info
);
581 (first
->flags
& SIGQUEUE_PREALLOC
) &&
582 (info
->si_code
== SI_TIMER
) &&
583 (info
->si_sys_private
);
585 __sigqueue_free(first
);
588 * Ok, it wasn't in the queue. This must be
589 * a fast-pathed signal or we must have been
590 * out of queue space. So zero out the info.
593 info
->si_signo
= sig
;
595 info
->si_code
= SI_USER
;
601 static int __dequeue_signal(struct sigpending
*pending
, sigset_t
*mask
,
602 kernel_siginfo_t
*info
, bool *resched_timer
)
604 int sig
= next_signal(pending
, mask
);
607 collect_signal(sig
, pending
, info
, resched_timer
);
612 * Dequeue a signal and return the element to the caller, which is
613 * expected to free it.
615 * All callers have to hold the siglock.
617 int dequeue_signal(struct task_struct
*tsk
, sigset_t
*mask
, kernel_siginfo_t
*info
)
619 bool resched_timer
= false;
622 /* We only dequeue private signals from ourselves, we don't let
623 * signalfd steal them
625 signr
= __dequeue_signal(&tsk
->pending
, mask
, info
, &resched_timer
);
627 signr
= __dequeue_signal(&tsk
->signal
->shared_pending
,
628 mask
, info
, &resched_timer
);
629 #ifdef CONFIG_POSIX_TIMERS
633 * itimers are process shared and we restart periodic
634 * itimers in the signal delivery path to prevent DoS
635 * attacks in the high resolution timer case. This is
636 * compliant with the old way of self-restarting
637 * itimers, as the SIGALRM is a legacy signal and only
638 * queued once. Changing the restart behaviour to
639 * restart the timer in the signal dequeue path is
640 * reducing the timer noise on heavy loaded !highres
643 if (unlikely(signr
== SIGALRM
)) {
644 struct hrtimer
*tmr
= &tsk
->signal
->real_timer
;
646 if (!hrtimer_is_queued(tmr
) &&
647 tsk
->signal
->it_real_incr
!= 0) {
648 hrtimer_forward(tmr
, tmr
->base
->get_time(),
649 tsk
->signal
->it_real_incr
);
650 hrtimer_restart(tmr
);
660 if (unlikely(sig_kernel_stop(signr
))) {
662 * Set a marker that we have dequeued a stop signal. Our
663 * caller might release the siglock and then the pending
664 * stop signal it is about to process is no longer in the
665 * pending bitmasks, but must still be cleared by a SIGCONT
666 * (and overruled by a SIGKILL). So those cases clear this
667 * shared flag after we've set it. Note that this flag may
668 * remain set after the signal we return is ignored or
669 * handled. That doesn't matter because its only purpose
670 * is to alert stop-signal processing code when another
671 * processor has come along and cleared the flag.
673 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
675 #ifdef CONFIG_POSIX_TIMERS
678 * Release the siglock to ensure proper locking order
679 * of timer locks outside of siglocks. Note, we leave
680 * irqs disabled here, since the posix-timers code is
681 * about to disable them again anyway.
683 spin_unlock(&tsk
->sighand
->siglock
);
684 posixtimer_rearm(info
);
685 spin_lock(&tsk
->sighand
->siglock
);
687 /* Don't expose the si_sys_private value to userspace */
688 info
->si_sys_private
= 0;
693 EXPORT_SYMBOL_GPL(dequeue_signal
);
695 static int dequeue_synchronous_signal(kernel_siginfo_t
*info
)
697 struct task_struct
*tsk
= current
;
698 struct sigpending
*pending
= &tsk
->pending
;
699 struct sigqueue
*q
, *sync
= NULL
;
702 * Might a synchronous signal be in the queue?
704 if (!((pending
->signal
.sig
[0] & ~tsk
->blocked
.sig
[0]) & SYNCHRONOUS_MASK
))
708 * Return the first synchronous signal in the queue.
710 list_for_each_entry(q
, &pending
->list
, list
) {
711 /* Synchronous signals have a postive si_code */
712 if ((q
->info
.si_code
> SI_USER
) &&
713 (sigmask(q
->info
.si_signo
) & SYNCHRONOUS_MASK
)) {
721 * Check if there is another siginfo for the same signal.
723 list_for_each_entry_continue(q
, &pending
->list
, list
) {
724 if (q
->info
.si_signo
== sync
->info
.si_signo
)
728 sigdelset(&pending
->signal
, sync
->info
.si_signo
);
731 list_del_init(&sync
->list
);
732 copy_siginfo(info
, &sync
->info
);
733 __sigqueue_free(sync
);
734 return info
->si_signo
;
738 * Tell a process that it has a new active signal..
740 * NOTE! we rely on the previous spin_lock to
741 * lock interrupts for us! We can only be called with
742 * "siglock" held, and the local interrupt must
743 * have been disabled when that got acquired!
745 * No need to set need_resched since signal event passing
746 * goes through ->blocked
748 void signal_wake_up_state(struct task_struct
*t
, unsigned int state
)
750 set_tsk_thread_flag(t
, TIF_SIGPENDING
);
752 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
753 * case. We don't check t->state here because there is a race with it
754 * executing another processor and just now entering stopped state.
755 * By using wake_up_state, we ensure the process will wake up and
756 * handle its death signal.
758 if (!wake_up_state(t
, state
| TASK_INTERRUPTIBLE
))
763 * Remove signals in mask from the pending set and queue.
764 * Returns 1 if any signals were found.
766 * All callers must be holding the siglock.
768 static void flush_sigqueue_mask(sigset_t
*mask
, struct sigpending
*s
)
770 struct sigqueue
*q
, *n
;
773 sigandsets(&m
, mask
, &s
->signal
);
774 if (sigisemptyset(&m
))
777 sigandnsets(&s
->signal
, &s
->signal
, mask
);
778 list_for_each_entry_safe(q
, n
, &s
->list
, list
) {
779 if (sigismember(mask
, q
->info
.si_signo
)) {
780 list_del_init(&q
->list
);
786 static inline int is_si_special(const struct kernel_siginfo
*info
)
788 return info
<= SEND_SIG_PRIV
;
791 static inline bool si_fromuser(const struct kernel_siginfo
*info
)
793 return info
== SEND_SIG_NOINFO
||
794 (!is_si_special(info
) && SI_FROMUSER(info
));
798 * called with RCU read lock from check_kill_permission()
800 static bool kill_ok_by_cred(struct task_struct
*t
)
802 const struct cred
*cred
= current_cred();
803 const struct cred
*tcred
= __task_cred(t
);
805 return uid_eq(cred
->euid
, tcred
->suid
) ||
806 uid_eq(cred
->euid
, tcred
->uid
) ||
807 uid_eq(cred
->uid
, tcred
->suid
) ||
808 uid_eq(cred
->uid
, tcred
->uid
) ||
809 ns_capable(tcred
->user_ns
, CAP_KILL
);
813 * Bad permissions for sending the signal
814 * - the caller must hold the RCU read lock
816 static int check_kill_permission(int sig
, struct kernel_siginfo
*info
,
817 struct task_struct
*t
)
822 if (!valid_signal(sig
))
825 if (!si_fromuser(info
))
828 error
= audit_signal_info(sig
, t
); /* Let audit system see the signal */
832 if (!same_thread_group(current
, t
) &&
833 !kill_ok_by_cred(t
)) {
836 sid
= task_session(t
);
838 * We don't return the error if sid == NULL. The
839 * task was unhashed, the caller must notice this.
841 if (!sid
|| sid
== task_session(current
))
849 return security_task_kill(t
, info
, sig
, NULL
);
853 * ptrace_trap_notify - schedule trap to notify ptracer
854 * @t: tracee wanting to notify tracer
856 * This function schedules sticky ptrace trap which is cleared on the next
857 * TRAP_STOP to notify ptracer of an event. @t must have been seized by
860 * If @t is running, STOP trap will be taken. If trapped for STOP and
861 * ptracer is listening for events, tracee is woken up so that it can
862 * re-trap for the new event. If trapped otherwise, STOP trap will be
863 * eventually taken without returning to userland after the existing traps
864 * are finished by PTRACE_CONT.
867 * Must be called with @task->sighand->siglock held.
869 static void ptrace_trap_notify(struct task_struct
*t
)
871 WARN_ON_ONCE(!(t
->ptrace
& PT_SEIZED
));
872 assert_spin_locked(&t
->sighand
->siglock
);
874 task_set_jobctl_pending(t
, JOBCTL_TRAP_NOTIFY
);
875 ptrace_signal_wake_up(t
, t
->jobctl
& JOBCTL_LISTENING
);
879 * Handle magic process-wide effects of stop/continue signals. Unlike
880 * the signal actions, these happen immediately at signal-generation
881 * time regardless of blocking, ignoring, or handling. This does the
882 * actual continuing for SIGCONT, but not the actual stopping for stop
883 * signals. The process stop is done as a signal action for SIG_DFL.
885 * Returns true if the signal should be actually delivered, otherwise
886 * it should be dropped.
888 static bool prepare_signal(int sig
, struct task_struct
*p
, bool force
)
890 struct signal_struct
*signal
= p
->signal
;
891 struct task_struct
*t
;
894 if (signal
->flags
& (SIGNAL_GROUP_EXIT
| SIGNAL_GROUP_COREDUMP
)) {
895 if (!(signal
->flags
& SIGNAL_GROUP_EXIT
))
896 return sig
== SIGKILL
;
898 * The process is in the middle of dying, nothing to do.
900 } else if (sig_kernel_stop(sig
)) {
902 * This is a stop signal. Remove SIGCONT from all queues.
904 siginitset(&flush
, sigmask(SIGCONT
));
905 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
906 for_each_thread(p
, t
)
907 flush_sigqueue_mask(&flush
, &t
->pending
);
908 } else if (sig
== SIGCONT
) {
911 * Remove all stop signals from all queues, wake all threads.
913 siginitset(&flush
, SIG_KERNEL_STOP_MASK
);
914 flush_sigqueue_mask(&flush
, &signal
->shared_pending
);
915 for_each_thread(p
, t
) {
916 flush_sigqueue_mask(&flush
, &t
->pending
);
917 task_clear_jobctl_pending(t
, JOBCTL_STOP_PENDING
);
918 if (likely(!(t
->ptrace
& PT_SEIZED
)))
919 wake_up_state(t
, __TASK_STOPPED
);
921 ptrace_trap_notify(t
);
925 * Notify the parent with CLD_CONTINUED if we were stopped.
927 * If we were in the middle of a group stop, we pretend it
928 * was already finished, and then continued. Since SIGCHLD
929 * doesn't queue we report only CLD_STOPPED, as if the next
930 * CLD_CONTINUED was dropped.
933 if (signal
->flags
& SIGNAL_STOP_STOPPED
)
934 why
|= SIGNAL_CLD_CONTINUED
;
935 else if (signal
->group_stop_count
)
936 why
|= SIGNAL_CLD_STOPPED
;
940 * The first thread which returns from do_signal_stop()
941 * will take ->siglock, notice SIGNAL_CLD_MASK, and
942 * notify its parent. See get_signal().
944 signal_set_stop_flags(signal
, why
| SIGNAL_STOP_CONTINUED
);
945 signal
->group_stop_count
= 0;
946 signal
->group_exit_code
= 0;
950 return !sig_ignored(p
, sig
, force
);
954 * Test if P wants to take SIG. After we've checked all threads with this,
955 * it's equivalent to finding no threads not blocking SIG. Any threads not
956 * blocking SIG were ruled out because they are not running and already
957 * have pending signals. Such threads will dequeue from the shared queue
958 * as soon as they're available, so putting the signal on the shared queue
959 * will be equivalent to sending it to one such thread.
961 static inline bool wants_signal(int sig
, struct task_struct
*p
)
963 if (sigismember(&p
->blocked
, sig
))
966 if (p
->flags
& PF_EXITING
)
972 if (task_is_stopped_or_traced(p
))
975 return task_curr(p
) || !signal_pending(p
);
978 static void complete_signal(int sig
, struct task_struct
*p
, enum pid_type type
)
980 struct signal_struct
*signal
= p
->signal
;
981 struct task_struct
*t
;
984 * Now find a thread we can wake up to take the signal off the queue.
986 * If the main thread wants the signal, it gets first crack.
987 * Probably the least surprising to the average bear.
989 if (wants_signal(sig
, p
))
991 else if ((type
== PIDTYPE_PID
) || thread_group_empty(p
))
993 * There is just one thread and it does not need to be woken.
994 * It will dequeue unblocked signals before it runs again.
999 * Otherwise try to find a suitable thread.
1001 t
= signal
->curr_target
;
1002 while (!wants_signal(sig
, t
)) {
1004 if (t
== signal
->curr_target
)
1006 * No thread needs to be woken.
1007 * Any eligible threads will see
1008 * the signal in the queue soon.
1012 signal
->curr_target
= t
;
1016 * Found a killable thread. If the signal will be fatal,
1017 * then start taking the whole group down immediately.
1019 if (sig_fatal(p
, sig
) &&
1020 !(signal
->flags
& SIGNAL_GROUP_EXIT
) &&
1021 !sigismember(&t
->real_blocked
, sig
) &&
1022 (sig
== SIGKILL
|| !p
->ptrace
)) {
1024 * This signal will be fatal to the whole group.
1026 if (!sig_kernel_coredump(sig
)) {
1028 * Start a group exit and wake everybody up.
1029 * This way we don't have other threads
1030 * running and doing things after a slower
1031 * thread has the fatal signal pending.
1033 signal
->flags
= SIGNAL_GROUP_EXIT
;
1034 signal
->group_exit_code
= sig
;
1035 signal
->group_stop_count
= 0;
1038 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
1039 sigaddset(&t
->pending
.signal
, SIGKILL
);
1040 signal_wake_up(t
, 1);
1041 } while_each_thread(p
, t
);
1047 * The signal is already in the shared-pending queue.
1048 * Tell the chosen thread to wake up and dequeue it.
1050 signal_wake_up(t
, sig
== SIGKILL
);
1054 static inline bool legacy_queue(struct sigpending
*signals
, int sig
)
1056 return (sig
< SIGRTMIN
) && sigismember(&signals
->signal
, sig
);
1059 static int __send_signal(int sig
, struct kernel_siginfo
*info
, struct task_struct
*t
,
1060 enum pid_type type
, int from_ancestor_ns
)
1062 struct sigpending
*pending
;
1064 int override_rlimit
;
1065 int ret
= 0, result
;
1067 assert_spin_locked(&t
->sighand
->siglock
);
1069 result
= TRACE_SIGNAL_IGNORED
;
1070 if (!prepare_signal(sig
, t
,
1071 from_ancestor_ns
|| (info
== SEND_SIG_PRIV
)))
1074 pending
= (type
!= PIDTYPE_PID
) ? &t
->signal
->shared_pending
: &t
->pending
;
1076 * Short-circuit ignored signals and support queuing
1077 * exactly one non-rt signal, so that we can get more
1078 * detailed information about the cause of the signal.
1080 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1081 if (legacy_queue(pending
, sig
))
1084 result
= TRACE_SIGNAL_DELIVERED
;
1086 * Skip useless siginfo allocation for SIGKILL and kernel threads.
1088 if ((sig
== SIGKILL
) || (t
->flags
& PF_KTHREAD
))
1092 * Real-time signals must be queued if sent by sigqueue, or
1093 * some other real-time mechanism. It is implementation
1094 * defined whether kill() does so. We attempt to do so, on
1095 * the principle of least surprise, but since kill is not
1096 * allowed to fail with EAGAIN when low on memory we just
1097 * make sure at least one signal gets delivered and don't
1098 * pass on the info struct.
1101 override_rlimit
= (is_si_special(info
) || info
->si_code
>= 0);
1103 override_rlimit
= 0;
1105 q
= __sigqueue_alloc(sig
, t
, GFP_ATOMIC
, override_rlimit
);
1107 list_add_tail(&q
->list
, &pending
->list
);
1108 switch ((unsigned long) info
) {
1109 case (unsigned long) SEND_SIG_NOINFO
:
1110 clear_siginfo(&q
->info
);
1111 q
->info
.si_signo
= sig
;
1112 q
->info
.si_errno
= 0;
1113 q
->info
.si_code
= SI_USER
;
1114 q
->info
.si_pid
= task_tgid_nr_ns(current
,
1115 task_active_pid_ns(t
));
1118 from_kuid_munged(task_cred_xxx(t
, user_ns
),
1122 case (unsigned long) SEND_SIG_PRIV
:
1123 clear_siginfo(&q
->info
);
1124 q
->info
.si_signo
= sig
;
1125 q
->info
.si_errno
= 0;
1126 q
->info
.si_code
= SI_KERNEL
;
1131 copy_siginfo(&q
->info
, info
);
1134 } else if (!is_si_special(info
)) {
1135 if (sig
>= SIGRTMIN
&& info
->si_code
!= SI_USER
) {
1137 * Queue overflow, abort. We may abort if the
1138 * signal was rt and sent by user using something
1139 * other than kill().
1141 result
= TRACE_SIGNAL_OVERFLOW_FAIL
;
1146 * This is a silent loss of information. We still
1147 * send the signal, but the *info bits are lost.
1149 result
= TRACE_SIGNAL_LOSE_INFO
;
1154 signalfd_notify(t
, sig
);
1155 sigaddset(&pending
->signal
, sig
);
1157 /* Let multiprocess signals appear after on-going forks */
1158 if (type
> PIDTYPE_TGID
) {
1159 struct multiprocess_signals
*delayed
;
1160 hlist_for_each_entry(delayed
, &t
->signal
->multiprocess
, node
) {
1161 sigset_t
*signal
= &delayed
->signal
;
1162 /* Can't queue both a stop and a continue signal */
1164 sigdelsetmask(signal
, SIG_KERNEL_STOP_MASK
);
1165 else if (sig_kernel_stop(sig
))
1166 sigdelset(signal
, SIGCONT
);
1167 sigaddset(signal
, sig
);
1171 complete_signal(sig
, t
, type
);
1173 trace_signal_generate(sig
, info
, t
, type
!= PIDTYPE_PID
, result
);
1177 static inline bool has_si_pid_and_uid(struct kernel_siginfo
*info
)
1180 switch (siginfo_layout(info
->si_signo
, info
->si_code
)) {
1189 case SIL_FAULT_MCEERR
:
1190 case SIL_FAULT_BNDERR
:
1191 case SIL_FAULT_PKUERR
:
1199 static int send_signal(int sig
, struct kernel_siginfo
*info
, struct task_struct
*t
,
1202 int from_ancestor_ns
= 0;
1204 #ifdef CONFIG_PID_NS
1205 from_ancestor_ns
= si_fromuser(info
) &&
1206 !task_pid_nr_ns(current
, task_active_pid_ns(t
));
1208 if (!is_si_special(info
) && has_si_pid_and_uid(info
)) {
1209 struct user_namespace
*t_user_ns
;
1212 t_user_ns
= task_cred_xxx(t
, user_ns
);
1213 if (current_user_ns() != t_user_ns
) {
1214 kuid_t uid
= make_kuid(current_user_ns(), info
->si_uid
);
1215 info
->si_uid
= from_kuid_munged(t_user_ns
, uid
);
1219 if (!task_pid_nr_ns(current
, task_active_pid_ns(t
)))
1222 return __send_signal(sig
, info
, t
, type
, from_ancestor_ns
);
1225 static void print_fatal_signal(int signr
)
1227 struct pt_regs
*regs
= signal_pt_regs();
1228 pr_info("potentially unexpected fatal signal %d.\n", signr
);
1230 #if defined(__i386__) && !defined(__arch_um__)
1231 pr_info("code at %08lx: ", regs
->ip
);
1234 for (i
= 0; i
< 16; i
++) {
1237 if (get_user(insn
, (unsigned char *)(regs
->ip
+ i
)))
1239 pr_cont("%02x ", insn
);
1249 static int __init
setup_print_fatal_signals(char *str
)
1251 get_option (&str
, &print_fatal_signals
);
1256 __setup("print-fatal-signals=", setup_print_fatal_signals
);
1259 __group_send_sig_info(int sig
, struct kernel_siginfo
*info
, struct task_struct
*p
)
1261 return send_signal(sig
, info
, p
, PIDTYPE_TGID
);
1264 int do_send_sig_info(int sig
, struct kernel_siginfo
*info
, struct task_struct
*p
,
1267 unsigned long flags
;
1270 if (lock_task_sighand(p
, &flags
)) {
1271 ret
= send_signal(sig
, info
, p
, type
);
1272 unlock_task_sighand(p
, &flags
);
1279 * Force a signal that the process can't ignore: if necessary
1280 * we unblock the signal and change any SIG_IGN to SIG_DFL.
1282 * Note: If we unblock the signal, we always reset it to SIG_DFL,
1283 * since we do not want to have a signal handler that was blocked
1284 * be invoked when user space had explicitly blocked it.
1286 * We don't want to have recursive SIGSEGV's etc, for example,
1287 * that is why we also clear SIGNAL_UNKILLABLE.
1290 force_sig_info(int sig
, struct kernel_siginfo
*info
, struct task_struct
*t
)
1292 unsigned long int flags
;
1293 int ret
, blocked
, ignored
;
1294 struct k_sigaction
*action
;
1296 spin_lock_irqsave(&t
->sighand
->siglock
, flags
);
1297 action
= &t
->sighand
->action
[sig
-1];
1298 ignored
= action
->sa
.sa_handler
== SIG_IGN
;
1299 blocked
= sigismember(&t
->blocked
, sig
);
1300 if (blocked
|| ignored
) {
1301 action
->sa
.sa_handler
= SIG_DFL
;
1303 sigdelset(&t
->blocked
, sig
);
1304 recalc_sigpending_and_wake(t
);
1308 * Don't clear SIGNAL_UNKILLABLE for traced tasks, users won't expect
1309 * debugging to leave init killable.
1311 if (action
->sa
.sa_handler
== SIG_DFL
&& !t
->ptrace
)
1312 t
->signal
->flags
&= ~SIGNAL_UNKILLABLE
;
1313 ret
= send_signal(sig
, info
, t
, PIDTYPE_PID
);
1314 spin_unlock_irqrestore(&t
->sighand
->siglock
, flags
);
1320 * Nuke all other threads in the group.
1322 int zap_other_threads(struct task_struct
*p
)
1324 struct task_struct
*t
= p
;
1327 p
->signal
->group_stop_count
= 0;
1329 while_each_thread(p
, t
) {
1330 task_clear_jobctl_pending(t
, JOBCTL_PENDING_MASK
);
1333 /* Don't bother with already dead threads */
1336 sigaddset(&t
->pending
.signal
, SIGKILL
);
1337 signal_wake_up(t
, 1);
1343 struct sighand_struct
*__lock_task_sighand(struct task_struct
*tsk
,
1344 unsigned long *flags
)
1346 struct sighand_struct
*sighand
;
1350 sighand
= rcu_dereference(tsk
->sighand
);
1351 if (unlikely(sighand
== NULL
))
1355 * This sighand can be already freed and even reused, but
1356 * we rely on SLAB_TYPESAFE_BY_RCU and sighand_ctor() which
1357 * initializes ->siglock: this slab can't go away, it has
1358 * the same object type, ->siglock can't be reinitialized.
1360 * We need to ensure that tsk->sighand is still the same
1361 * after we take the lock, we can race with de_thread() or
1362 * __exit_signal(). In the latter case the next iteration
1363 * must see ->sighand == NULL.
1365 spin_lock_irqsave(&sighand
->siglock
, *flags
);
1366 if (likely(sighand
== tsk
->sighand
))
1368 spin_unlock_irqrestore(&sighand
->siglock
, *flags
);
1376 * send signal info to all the members of a group
1378 int group_send_sig_info(int sig
, struct kernel_siginfo
*info
,
1379 struct task_struct
*p
, enum pid_type type
)
1384 ret
= check_kill_permission(sig
, info
, p
);
1388 ret
= do_send_sig_info(sig
, info
, p
, type
);
1394 * __kill_pgrp_info() sends a signal to a process group: this is what the tty
1395 * control characters do (^C, ^Z etc)
1396 * - the caller must hold at least a readlock on tasklist_lock
1398 int __kill_pgrp_info(int sig
, struct kernel_siginfo
*info
, struct pid
*pgrp
)
1400 struct task_struct
*p
= NULL
;
1401 int retval
, success
;
1405 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
1406 int err
= group_send_sig_info(sig
, info
, p
, PIDTYPE_PGID
);
1409 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
1410 return success
? 0 : retval
;
1413 int kill_pid_info(int sig
, struct kernel_siginfo
*info
, struct pid
*pid
)
1416 struct task_struct
*p
;
1420 p
= pid_task(pid
, PIDTYPE_PID
);
1422 error
= group_send_sig_info(sig
, info
, p
, PIDTYPE_TGID
);
1424 if (likely(!p
|| error
!= -ESRCH
))
1428 * The task was unhashed in between, try again. If it
1429 * is dead, pid_task() will return NULL, if we race with
1430 * de_thread() it will find the new leader.
1435 static int kill_proc_info(int sig
, struct kernel_siginfo
*info
, pid_t pid
)
1439 error
= kill_pid_info(sig
, info
, find_vpid(pid
));
1444 static inline bool kill_as_cred_perm(const struct cred
*cred
,
1445 struct task_struct
*target
)
1447 const struct cred
*pcred
= __task_cred(target
);
1449 return uid_eq(cred
->euid
, pcred
->suid
) ||
1450 uid_eq(cred
->euid
, pcred
->uid
) ||
1451 uid_eq(cred
->uid
, pcred
->suid
) ||
1452 uid_eq(cred
->uid
, pcred
->uid
);
1456 * The usb asyncio usage of siginfo is wrong. The glibc support
1457 * for asyncio which uses SI_ASYNCIO assumes the layout is SIL_RT.
1458 * AKA after the generic fields:
1459 * kernel_pid_t si_pid;
1460 * kernel_uid32_t si_uid;
1461 * sigval_t si_value;
1463 * Unfortunately when usb generates SI_ASYNCIO it assumes the layout
1464 * after the generic fields is:
1465 * void __user *si_addr;
1467 * This is a practical problem when there is a 64bit big endian kernel
1468 * and a 32bit userspace. As the 32bit address will encoded in the low
1469 * 32bits of the pointer. Those low 32bits will be stored at higher
1470 * address than appear in a 32 bit pointer. So userspace will not
1471 * see the address it was expecting for it's completions.
1473 * There is nothing in the encoding that can allow
1474 * copy_siginfo_to_user32 to detect this confusion of formats, so
1475 * handle this by requiring the caller of kill_pid_usb_asyncio to
1476 * notice when this situration takes place and to store the 32bit
1477 * pointer in sival_int, instead of sival_addr of the sigval_t addr
1480 int kill_pid_usb_asyncio(int sig
, int errno
, sigval_t addr
,
1481 struct pid
*pid
, const struct cred
*cred
)
1483 struct kernel_siginfo info
;
1484 struct task_struct
*p
;
1485 unsigned long flags
;
1488 clear_siginfo(&info
);
1489 info
.si_signo
= sig
;
1490 info
.si_errno
= errno
;
1491 info
.si_code
= SI_ASYNCIO
;
1492 *((sigval_t
*)&info
.si_pid
) = addr
;
1494 if (!valid_signal(sig
))
1498 p
= pid_task(pid
, PIDTYPE_PID
);
1503 if (!kill_as_cred_perm(cred
, p
)) {
1507 ret
= security_task_kill(p
, &info
, sig
, cred
);
1512 if (lock_task_sighand(p
, &flags
)) {
1513 ret
= __send_signal(sig
, &info
, p
, PIDTYPE_TGID
, 0);
1514 unlock_task_sighand(p
, &flags
);
1522 EXPORT_SYMBOL_GPL(kill_pid_usb_asyncio
);
1525 * kill_something_info() interprets pid in interesting ways just like kill(2).
1527 * POSIX specifies that kill(-1,sig) is unspecified, but what we have
1528 * is probably wrong. Should make it like BSD or SYSV.
1531 static int kill_something_info(int sig
, struct kernel_siginfo
*info
, pid_t pid
)
1537 ret
= kill_pid_info(sig
, info
, find_vpid(pid
));
1542 /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */
1546 read_lock(&tasklist_lock
);
1548 ret
= __kill_pgrp_info(sig
, info
,
1549 pid
? find_vpid(-pid
) : task_pgrp(current
));
1551 int retval
= 0, count
= 0;
1552 struct task_struct
* p
;
1554 for_each_process(p
) {
1555 if (task_pid_vnr(p
) > 1 &&
1556 !same_thread_group(p
, current
)) {
1557 int err
= group_send_sig_info(sig
, info
, p
,
1564 ret
= count
? retval
: -ESRCH
;
1566 read_unlock(&tasklist_lock
);
1572 * These are for backward compatibility with the rest of the kernel source.
1575 int send_sig_info(int sig
, struct kernel_siginfo
*info
, struct task_struct
*p
)
1578 * Make sure legacy kernel users don't send in bad values
1579 * (normal paths check this in check_kill_permission).
1581 if (!valid_signal(sig
))
1584 return do_send_sig_info(sig
, info
, p
, PIDTYPE_PID
);
1586 EXPORT_SYMBOL(send_sig_info
);
1588 #define __si_special(priv) \
1589 ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO)
1592 send_sig(int sig
, struct task_struct
*p
, int priv
)
1594 return send_sig_info(sig
, __si_special(priv
), p
);
1596 EXPORT_SYMBOL(send_sig
);
1598 void force_sig(int sig
, struct task_struct
*p
)
1600 force_sig_info(sig
, SEND_SIG_PRIV
, p
);
1602 EXPORT_SYMBOL(force_sig
);
1605 * When things go south during signal handling, we
1606 * will force a SIGSEGV. And if the signal that caused
1607 * the problem was already a SIGSEGV, we'll want to
1608 * make sure we don't even try to deliver the signal..
1610 void force_sigsegv(int sig
)
1612 struct task_struct
*p
= current
;
1614 if (sig
== SIGSEGV
) {
1615 unsigned long flags
;
1616 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
1617 p
->sighand
->action
[sig
- 1].sa
.sa_handler
= SIG_DFL
;
1618 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
1620 force_sig(SIGSEGV
, p
);
1623 int force_sig_fault(int sig
, int code
, void __user
*addr
1624 ___ARCH_SI_TRAPNO(int trapno
)
1625 ___ARCH_SI_IA64(int imm
, unsigned int flags
, unsigned long isr
)
1626 , struct task_struct
*t
)
1628 struct kernel_siginfo info
;
1630 clear_siginfo(&info
);
1631 info
.si_signo
= sig
;
1633 info
.si_code
= code
;
1634 info
.si_addr
= addr
;
1635 #ifdef __ARCH_SI_TRAPNO
1636 info
.si_trapno
= trapno
;
1640 info
.si_flags
= flags
;
1643 return force_sig_info(info
.si_signo
, &info
, t
);
1646 int send_sig_fault(int sig
, int code
, void __user
*addr
1647 ___ARCH_SI_TRAPNO(int trapno
)
1648 ___ARCH_SI_IA64(int imm
, unsigned int flags
, unsigned long isr
)
1649 , struct task_struct
*t
)
1651 struct kernel_siginfo info
;
1653 clear_siginfo(&info
);
1654 info
.si_signo
= sig
;
1656 info
.si_code
= code
;
1657 info
.si_addr
= addr
;
1658 #ifdef __ARCH_SI_TRAPNO
1659 info
.si_trapno
= trapno
;
1663 info
.si_flags
= flags
;
1666 return send_sig_info(info
.si_signo
, &info
, t
);
1669 int force_sig_mceerr(int code
, void __user
*addr
, short lsb
, struct task_struct
*t
)
1671 struct kernel_siginfo info
;
1673 WARN_ON((code
!= BUS_MCEERR_AO
) && (code
!= BUS_MCEERR_AR
));
1674 clear_siginfo(&info
);
1675 info
.si_signo
= SIGBUS
;
1677 info
.si_code
= code
;
1678 info
.si_addr
= addr
;
1679 info
.si_addr_lsb
= lsb
;
1680 return force_sig_info(info
.si_signo
, &info
, t
);
1683 int send_sig_mceerr(int code
, void __user
*addr
, short lsb
, struct task_struct
*t
)
1685 struct kernel_siginfo info
;
1687 WARN_ON((code
!= BUS_MCEERR_AO
) && (code
!= BUS_MCEERR_AR
));
1688 clear_siginfo(&info
);
1689 info
.si_signo
= SIGBUS
;
1691 info
.si_code
= code
;
1692 info
.si_addr
= addr
;
1693 info
.si_addr_lsb
= lsb
;
1694 return send_sig_info(info
.si_signo
, &info
, t
);
1696 EXPORT_SYMBOL(send_sig_mceerr
);
1698 int force_sig_bnderr(void __user
*addr
, void __user
*lower
, void __user
*upper
)
1700 struct kernel_siginfo info
;
1702 clear_siginfo(&info
);
1703 info
.si_signo
= SIGSEGV
;
1705 info
.si_code
= SEGV_BNDERR
;
1706 info
.si_addr
= addr
;
1707 info
.si_lower
= lower
;
1708 info
.si_upper
= upper
;
1709 return force_sig_info(info
.si_signo
, &info
, current
);
1713 int force_sig_pkuerr(void __user
*addr
, u32 pkey
)
1715 struct kernel_siginfo info
;
1717 clear_siginfo(&info
);
1718 info
.si_signo
= SIGSEGV
;
1720 info
.si_code
= SEGV_PKUERR
;
1721 info
.si_addr
= addr
;
1722 info
.si_pkey
= pkey
;
1723 return force_sig_info(info
.si_signo
, &info
, current
);
1727 /* For the crazy architectures that include trap information in
1728 * the errno field, instead of an actual errno value.
1730 int force_sig_ptrace_errno_trap(int errno
, void __user
*addr
)
1732 struct kernel_siginfo info
;
1734 clear_siginfo(&info
);
1735 info
.si_signo
= SIGTRAP
;
1736 info
.si_errno
= errno
;
1737 info
.si_code
= TRAP_HWBKPT
;
1738 info
.si_addr
= addr
;
1739 return force_sig_info(info
.si_signo
, &info
, current
);
1742 int kill_pgrp(struct pid
*pid
, int sig
, int priv
)
1746 read_lock(&tasklist_lock
);
1747 ret
= __kill_pgrp_info(sig
, __si_special(priv
), pid
);
1748 read_unlock(&tasklist_lock
);
1752 EXPORT_SYMBOL(kill_pgrp
);
1754 int kill_pid(struct pid
*pid
, int sig
, int priv
)
1756 return kill_pid_info(sig
, __si_special(priv
), pid
);
1758 EXPORT_SYMBOL(kill_pid
);
1761 * These functions support sending signals using preallocated sigqueue
1762 * structures. This is needed "because realtime applications cannot
1763 * afford to lose notifications of asynchronous events, like timer
1764 * expirations or I/O completions". In the case of POSIX Timers
1765 * we allocate the sigqueue structure from the timer_create. If this
1766 * allocation fails we are able to report the failure to the application
1767 * with an EAGAIN error.
1769 struct sigqueue
*sigqueue_alloc(void)
1771 struct sigqueue
*q
= __sigqueue_alloc(-1, current
, GFP_KERNEL
, 0);
1774 q
->flags
|= SIGQUEUE_PREALLOC
;
1779 void sigqueue_free(struct sigqueue
*q
)
1781 unsigned long flags
;
1782 spinlock_t
*lock
= ¤t
->sighand
->siglock
;
1784 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1786 * We must hold ->siglock while testing q->list
1787 * to serialize with collect_signal() or with
1788 * __exit_signal()->flush_sigqueue().
1790 spin_lock_irqsave(lock
, flags
);
1791 q
->flags
&= ~SIGQUEUE_PREALLOC
;
1793 * If it is queued it will be freed when dequeued,
1794 * like the "regular" sigqueue.
1796 if (!list_empty(&q
->list
))
1798 spin_unlock_irqrestore(lock
, flags
);
1804 int send_sigqueue(struct sigqueue
*q
, struct pid
*pid
, enum pid_type type
)
1806 int sig
= q
->info
.si_signo
;
1807 struct sigpending
*pending
;
1808 struct task_struct
*t
;
1809 unsigned long flags
;
1812 BUG_ON(!(q
->flags
& SIGQUEUE_PREALLOC
));
1816 t
= pid_task(pid
, type
);
1817 if (!t
|| !likely(lock_task_sighand(t
, &flags
)))
1820 ret
= 1; /* the signal is ignored */
1821 result
= TRACE_SIGNAL_IGNORED
;
1822 if (!prepare_signal(sig
, t
, false))
1826 if (unlikely(!list_empty(&q
->list
))) {
1828 * If an SI_TIMER entry is already queue just increment
1829 * the overrun count.
1831 BUG_ON(q
->info
.si_code
!= SI_TIMER
);
1832 q
->info
.si_overrun
++;
1833 result
= TRACE_SIGNAL_ALREADY_PENDING
;
1836 q
->info
.si_overrun
= 0;
1838 signalfd_notify(t
, sig
);
1839 pending
= (type
!= PIDTYPE_PID
) ? &t
->signal
->shared_pending
: &t
->pending
;
1840 list_add_tail(&q
->list
, &pending
->list
);
1841 sigaddset(&pending
->signal
, sig
);
1842 complete_signal(sig
, t
, type
);
1843 result
= TRACE_SIGNAL_DELIVERED
;
1845 trace_signal_generate(sig
, &q
->info
, t
, type
!= PIDTYPE_PID
, result
);
1846 unlock_task_sighand(t
, &flags
);
1853 * Let a parent know about the death of a child.
1854 * For a stopped/continued status change, use do_notify_parent_cldstop instead.
1856 * Returns true if our parent ignored us and so we've switched to
1859 bool do_notify_parent(struct task_struct
*tsk
, int sig
)
1861 struct kernel_siginfo info
;
1862 unsigned long flags
;
1863 struct sighand_struct
*psig
;
1864 bool autoreap
= false;
1869 /* do_notify_parent_cldstop should have been called instead. */
1870 BUG_ON(task_is_stopped_or_traced(tsk
));
1872 BUG_ON(!tsk
->ptrace
&&
1873 (tsk
->group_leader
!= tsk
|| !thread_group_empty(tsk
)));
1875 if (sig
!= SIGCHLD
) {
1877 * This is only possible if parent == real_parent.
1878 * Check if it has changed security domain.
1880 if (tsk
->parent_exec_id
!= tsk
->parent
->self_exec_id
)
1884 clear_siginfo(&info
);
1885 info
.si_signo
= sig
;
1888 * We are under tasklist_lock here so our parent is tied to
1889 * us and cannot change.
1891 * task_active_pid_ns will always return the same pid namespace
1892 * until a task passes through release_task.
1894 * write_lock() currently calls preempt_disable() which is the
1895 * same as rcu_read_lock(), but according to Oleg, this is not
1896 * correct to rely on this
1899 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(tsk
->parent
));
1900 info
.si_uid
= from_kuid_munged(task_cred_xxx(tsk
->parent
, user_ns
),
1904 task_cputime(tsk
, &utime
, &stime
);
1905 info
.si_utime
= nsec_to_clock_t(utime
+ tsk
->signal
->utime
);
1906 info
.si_stime
= nsec_to_clock_t(stime
+ tsk
->signal
->stime
);
1908 info
.si_status
= tsk
->exit_code
& 0x7f;
1909 if (tsk
->exit_code
& 0x80)
1910 info
.si_code
= CLD_DUMPED
;
1911 else if (tsk
->exit_code
& 0x7f)
1912 info
.si_code
= CLD_KILLED
;
1914 info
.si_code
= CLD_EXITED
;
1915 info
.si_status
= tsk
->exit_code
>> 8;
1918 psig
= tsk
->parent
->sighand
;
1919 spin_lock_irqsave(&psig
->siglock
, flags
);
1920 if (!tsk
->ptrace
&& sig
== SIGCHLD
&&
1921 (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
||
1922 (psig
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDWAIT
))) {
1924 * We are exiting and our parent doesn't care. POSIX.1
1925 * defines special semantics for setting SIGCHLD to SIG_IGN
1926 * or setting the SA_NOCLDWAIT flag: we should be reaped
1927 * automatically and not left for our parent's wait4 call.
1928 * Rather than having the parent do it as a magic kind of
1929 * signal handler, we just set this to tell do_exit that we
1930 * can be cleaned up without becoming a zombie. Note that
1931 * we still call __wake_up_parent in this case, because a
1932 * blocked sys_wait4 might now return -ECHILD.
1934 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
1935 * is implementation-defined: we do (if you don't want
1936 * it, just use SIG_IGN instead).
1939 if (psig
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
)
1942 if (valid_signal(sig
) && sig
)
1943 __group_send_sig_info(sig
, &info
, tsk
->parent
);
1944 __wake_up_parent(tsk
, tsk
->parent
);
1945 spin_unlock_irqrestore(&psig
->siglock
, flags
);
1951 * do_notify_parent_cldstop - notify parent of stopped/continued state change
1952 * @tsk: task reporting the state change
1953 * @for_ptracer: the notification is for ptracer
1954 * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
1956 * Notify @tsk's parent that the stopped/continued state has changed. If
1957 * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
1958 * If %true, @tsk reports to @tsk->parent which should be the ptracer.
1961 * Must be called with tasklist_lock at least read locked.
1963 static void do_notify_parent_cldstop(struct task_struct
*tsk
,
1964 bool for_ptracer
, int why
)
1966 struct kernel_siginfo info
;
1967 unsigned long flags
;
1968 struct task_struct
*parent
;
1969 struct sighand_struct
*sighand
;
1973 parent
= tsk
->parent
;
1975 tsk
= tsk
->group_leader
;
1976 parent
= tsk
->real_parent
;
1979 clear_siginfo(&info
);
1980 info
.si_signo
= SIGCHLD
;
1983 * see comment in do_notify_parent() about the following 4 lines
1986 info
.si_pid
= task_pid_nr_ns(tsk
, task_active_pid_ns(parent
));
1987 info
.si_uid
= from_kuid_munged(task_cred_xxx(parent
, user_ns
), task_uid(tsk
));
1990 task_cputime(tsk
, &utime
, &stime
);
1991 info
.si_utime
= nsec_to_clock_t(utime
);
1992 info
.si_stime
= nsec_to_clock_t(stime
);
1997 info
.si_status
= SIGCONT
;
2000 info
.si_status
= tsk
->signal
->group_exit_code
& 0x7f;
2003 info
.si_status
= tsk
->exit_code
& 0x7f;
2009 sighand
= parent
->sighand
;
2010 spin_lock_irqsave(&sighand
->siglock
, flags
);
2011 if (sighand
->action
[SIGCHLD
-1].sa
.sa_handler
!= SIG_IGN
&&
2012 !(sighand
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDSTOP
))
2013 __group_send_sig_info(SIGCHLD
, &info
, parent
);
2015 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
2017 __wake_up_parent(tsk
, parent
);
2018 spin_unlock_irqrestore(&sighand
->siglock
, flags
);
2021 static inline bool may_ptrace_stop(void)
2023 if (!likely(current
->ptrace
))
2026 * Are we in the middle of do_coredump?
2027 * If so and our tracer is also part of the coredump stopping
2028 * is a deadlock situation, and pointless because our tracer
2029 * is dead so don't allow us to stop.
2030 * If SIGKILL was already sent before the caller unlocked
2031 * ->siglock we must see ->core_state != NULL. Otherwise it
2032 * is safe to enter schedule().
2034 * This is almost outdated, a task with the pending SIGKILL can't
2035 * block in TASK_TRACED. But PTRACE_EVENT_EXIT can be reported
2036 * after SIGKILL was already dequeued.
2038 if (unlikely(current
->mm
->core_state
) &&
2039 unlikely(current
->mm
== current
->parent
->mm
))
2046 * Return non-zero if there is a SIGKILL that should be waking us up.
2047 * Called with the siglock held.
2049 static bool sigkill_pending(struct task_struct
*tsk
)
2051 return sigismember(&tsk
->pending
.signal
, SIGKILL
) ||
2052 sigismember(&tsk
->signal
->shared_pending
.signal
, SIGKILL
);
2056 * This must be called with current->sighand->siglock held.
2058 * This should be the path for all ptrace stops.
2059 * We always set current->last_siginfo while stopped here.
2060 * That makes it a way to test a stopped process for
2061 * being ptrace-stopped vs being job-control-stopped.
2063 * If we actually decide not to stop at all because the tracer
2064 * is gone, we keep current->exit_code unless clear_code.
2066 static void ptrace_stop(int exit_code
, int why
, int clear_code
, kernel_siginfo_t
*info
)
2067 __releases(¤t
->sighand
->siglock
)
2068 __acquires(¤t
->sighand
->siglock
)
2070 bool gstop_done
= false;
2072 if (arch_ptrace_stop_needed(exit_code
, info
)) {
2074 * The arch code has something special to do before a
2075 * ptrace stop. This is allowed to block, e.g. for faults
2076 * on user stack pages. We can't keep the siglock while
2077 * calling arch_ptrace_stop, so we must release it now.
2078 * To preserve proper semantics, we must do this before
2079 * any signal bookkeeping like checking group_stop_count.
2080 * Meanwhile, a SIGKILL could come in before we retake the
2081 * siglock. That must prevent us from sleeping in TASK_TRACED.
2082 * So after regaining the lock, we must check for SIGKILL.
2084 spin_unlock_irq(¤t
->sighand
->siglock
);
2085 arch_ptrace_stop(exit_code
, info
);
2086 spin_lock_irq(¤t
->sighand
->siglock
);
2087 if (sigkill_pending(current
))
2091 set_special_state(TASK_TRACED
);
2094 * We're committing to trapping. TRACED should be visible before
2095 * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
2096 * Also, transition to TRACED and updates to ->jobctl should be
2097 * atomic with respect to siglock and should be done after the arch
2098 * hook as siglock is released and regrabbed across it.
2103 * [L] wait_on_bit(JOBCTL_TRAPPING) [S] set_special_state(TRACED)
2105 * set_current_state() smp_wmb();
2107 * wait_task_stopped()
2108 * task_stopped_code()
2109 * [L] task_is_traced() [S] task_clear_jobctl_trapping();
2113 current
->last_siginfo
= info
;
2114 current
->exit_code
= exit_code
;
2117 * If @why is CLD_STOPPED, we're trapping to participate in a group
2118 * stop. Do the bookkeeping. Note that if SIGCONT was delievered
2119 * across siglock relocks since INTERRUPT was scheduled, PENDING
2120 * could be clear now. We act as if SIGCONT is received after
2121 * TASK_TRACED is entered - ignore it.
2123 if (why
== CLD_STOPPED
&& (current
->jobctl
& JOBCTL_STOP_PENDING
))
2124 gstop_done
= task_participate_group_stop(current
);
2126 /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
2127 task_clear_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
2128 if (info
&& info
->si_code
>> 8 == PTRACE_EVENT_STOP
)
2129 task_clear_jobctl_pending(current
, JOBCTL_TRAP_NOTIFY
);
2131 /* entering a trap, clear TRAPPING */
2132 task_clear_jobctl_trapping(current
);
2134 spin_unlock_irq(¤t
->sighand
->siglock
);
2135 read_lock(&tasklist_lock
);
2136 if (may_ptrace_stop()) {
2138 * Notify parents of the stop.
2140 * While ptraced, there are two parents - the ptracer and
2141 * the real_parent of the group_leader. The ptracer should
2142 * know about every stop while the real parent is only
2143 * interested in the completion of group stop. The states
2144 * for the two don't interact with each other. Notify
2145 * separately unless they're gonna be duplicates.
2147 do_notify_parent_cldstop(current
, true, why
);
2148 if (gstop_done
&& ptrace_reparented(current
))
2149 do_notify_parent_cldstop(current
, false, why
);
2152 * Don't want to allow preemption here, because
2153 * sys_ptrace() needs this task to be inactive.
2155 * XXX: implement read_unlock_no_resched().
2158 read_unlock(&tasklist_lock
);
2159 preempt_enable_no_resched();
2160 cgroup_enter_frozen();
2161 freezable_schedule();
2162 cgroup_leave_frozen(true);
2165 * By the time we got the lock, our tracer went away.
2166 * Don't drop the lock yet, another tracer may come.
2168 * If @gstop_done, the ptracer went away between group stop
2169 * completion and here. During detach, it would have set
2170 * JOBCTL_STOP_PENDING on us and we'll re-enter
2171 * TASK_STOPPED in do_signal_stop() on return, so notifying
2172 * the real parent of the group stop completion is enough.
2175 do_notify_parent_cldstop(current
, false, why
);
2177 /* tasklist protects us from ptrace_freeze_traced() */
2178 __set_current_state(TASK_RUNNING
);
2180 current
->exit_code
= 0;
2181 read_unlock(&tasklist_lock
);
2185 * We are back. Now reacquire the siglock before touching
2186 * last_siginfo, so that we are sure to have synchronized with
2187 * any signal-sending on another CPU that wants to examine it.
2189 spin_lock_irq(¤t
->sighand
->siglock
);
2190 current
->last_siginfo
= NULL
;
2192 /* LISTENING can be set only during STOP traps, clear it */
2193 current
->jobctl
&= ~JOBCTL_LISTENING
;
2196 * Queued signals ignored us while we were stopped for tracing.
2197 * So check for any that we should take before resuming user mode.
2198 * This sets TIF_SIGPENDING, but never clears it.
2200 recalc_sigpending_tsk(current
);
2203 static void ptrace_do_notify(int signr
, int exit_code
, int why
)
2205 kernel_siginfo_t info
;
2207 clear_siginfo(&info
);
2208 info
.si_signo
= signr
;
2209 info
.si_code
= exit_code
;
2210 info
.si_pid
= task_pid_vnr(current
);
2211 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
2213 /* Let the debugger run. */
2214 ptrace_stop(exit_code
, why
, 1, &info
);
2217 void ptrace_notify(int exit_code
)
2219 BUG_ON((exit_code
& (0x7f | ~0xffff)) != SIGTRAP
);
2220 if (unlikely(current
->task_works
))
2223 spin_lock_irq(¤t
->sighand
->siglock
);
2224 ptrace_do_notify(SIGTRAP
, exit_code
, CLD_TRAPPED
);
2225 spin_unlock_irq(¤t
->sighand
->siglock
);
2229 * do_signal_stop - handle group stop for SIGSTOP and other stop signals
2230 * @signr: signr causing group stop if initiating
2232 * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
2233 * and participate in it. If already set, participate in the existing
2234 * group stop. If participated in a group stop (and thus slept), %true is
2235 * returned with siglock released.
2237 * If ptraced, this function doesn't handle stop itself. Instead,
2238 * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
2239 * untouched. The caller must ensure that INTERRUPT trap handling takes
2240 * places afterwards.
2243 * Must be called with @current->sighand->siglock held, which is released
2247 * %false if group stop is already cancelled or ptrace trap is scheduled.
2248 * %true if participated in group stop.
2250 static bool do_signal_stop(int signr
)
2251 __releases(¤t
->sighand
->siglock
)
2253 struct signal_struct
*sig
= current
->signal
;
2255 if (!(current
->jobctl
& JOBCTL_STOP_PENDING
)) {
2256 unsigned long gstop
= JOBCTL_STOP_PENDING
| JOBCTL_STOP_CONSUME
;
2257 struct task_struct
*t
;
2259 /* signr will be recorded in task->jobctl for retries */
2260 WARN_ON_ONCE(signr
& ~JOBCTL_STOP_SIGMASK
);
2262 if (!likely(current
->jobctl
& JOBCTL_STOP_DEQUEUED
) ||
2263 unlikely(signal_group_exit(sig
)))
2266 * There is no group stop already in progress. We must
2269 * While ptraced, a task may be resumed while group stop is
2270 * still in effect and then receive a stop signal and
2271 * initiate another group stop. This deviates from the
2272 * usual behavior as two consecutive stop signals can't
2273 * cause two group stops when !ptraced. That is why we
2274 * also check !task_is_stopped(t) below.
2276 * The condition can be distinguished by testing whether
2277 * SIGNAL_STOP_STOPPED is already set. Don't generate
2278 * group_exit_code in such case.
2280 * This is not necessary for SIGNAL_STOP_CONTINUED because
2281 * an intervening stop signal is required to cause two
2282 * continued events regardless of ptrace.
2284 if (!(sig
->flags
& SIGNAL_STOP_STOPPED
))
2285 sig
->group_exit_code
= signr
;
2287 sig
->group_stop_count
= 0;
2289 if (task_set_jobctl_pending(current
, signr
| gstop
))
2290 sig
->group_stop_count
++;
2293 while_each_thread(current
, t
) {
2295 * Setting state to TASK_STOPPED for a group
2296 * stop is always done with the siglock held,
2297 * so this check has no races.
2299 if (!task_is_stopped(t
) &&
2300 task_set_jobctl_pending(t
, signr
| gstop
)) {
2301 sig
->group_stop_count
++;
2302 if (likely(!(t
->ptrace
& PT_SEIZED
)))
2303 signal_wake_up(t
, 0);
2305 ptrace_trap_notify(t
);
2310 if (likely(!current
->ptrace
)) {
2314 * If there are no other threads in the group, or if there
2315 * is a group stop in progress and we are the last to stop,
2316 * report to the parent.
2318 if (task_participate_group_stop(current
))
2319 notify
= CLD_STOPPED
;
2321 set_special_state(TASK_STOPPED
);
2322 spin_unlock_irq(¤t
->sighand
->siglock
);
2325 * Notify the parent of the group stop completion. Because
2326 * we're not holding either the siglock or tasklist_lock
2327 * here, ptracer may attach inbetween; however, this is for
2328 * group stop and should always be delivered to the real
2329 * parent of the group leader. The new ptracer will get
2330 * its notification when this task transitions into
2334 read_lock(&tasklist_lock
);
2335 do_notify_parent_cldstop(current
, false, notify
);
2336 read_unlock(&tasklist_lock
);
2339 /* Now we don't run again until woken by SIGCONT or SIGKILL */
2340 cgroup_enter_frozen();
2341 freezable_schedule();
2345 * While ptraced, group stop is handled by STOP trap.
2346 * Schedule it and let the caller deal with it.
2348 task_set_jobctl_pending(current
, JOBCTL_TRAP_STOP
);
2354 * do_jobctl_trap - take care of ptrace jobctl traps
2356 * When PT_SEIZED, it's used for both group stop and explicit
2357 * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
2358 * accompanying siginfo. If stopped, lower eight bits of exit_code contain
2359 * the stop signal; otherwise, %SIGTRAP.
2361 * When !PT_SEIZED, it's used only for group stop trap with stop signal
2362 * number as exit_code and no siginfo.
2365 * Must be called with @current->sighand->siglock held, which may be
2366 * released and re-acquired before returning with intervening sleep.
2368 static void do_jobctl_trap(void)
2370 struct signal_struct
*signal
= current
->signal
;
2371 int signr
= current
->jobctl
& JOBCTL_STOP_SIGMASK
;
2373 if (current
->ptrace
& PT_SEIZED
) {
2374 if (!signal
->group_stop_count
&&
2375 !(signal
->flags
& SIGNAL_STOP_STOPPED
))
2377 WARN_ON_ONCE(!signr
);
2378 ptrace_do_notify(signr
, signr
| (PTRACE_EVENT_STOP
<< 8),
2381 WARN_ON_ONCE(!signr
);
2382 ptrace_stop(signr
, CLD_STOPPED
, 0, NULL
);
2383 current
->exit_code
= 0;
2388 * do_freezer_trap - handle the freezer jobctl trap
2390 * Puts the task into frozen state, if only the task is not about to quit.
2391 * In this case it drops JOBCTL_TRAP_FREEZE.
2394 * Must be called with @current->sighand->siglock held,
2395 * which is always released before returning.
2397 static void do_freezer_trap(void)
2398 __releases(¤t
->sighand
->siglock
)
2401 * If there are other trap bits pending except JOBCTL_TRAP_FREEZE,
2402 * let's make another loop to give it a chance to be handled.
2403 * In any case, we'll return back.
2405 if ((current
->jobctl
& (JOBCTL_PENDING_MASK
| JOBCTL_TRAP_FREEZE
)) !=
2406 JOBCTL_TRAP_FREEZE
) {
2407 spin_unlock_irq(¤t
->sighand
->siglock
);
2412 * Now we're sure that there is no pending fatal signal and no
2413 * pending traps. Clear TIF_SIGPENDING to not get out of schedule()
2414 * immediately (if there is a non-fatal signal pending), and
2415 * put the task into sleep.
2417 __set_current_state(TASK_INTERRUPTIBLE
);
2418 clear_thread_flag(TIF_SIGPENDING
);
2419 spin_unlock_irq(¤t
->sighand
->siglock
);
2420 cgroup_enter_frozen();
2421 freezable_schedule();
2424 static int ptrace_signal(int signr
, kernel_siginfo_t
*info
)
2427 * We do not check sig_kernel_stop(signr) but set this marker
2428 * unconditionally because we do not know whether debugger will
2429 * change signr. This flag has no meaning unless we are going
2430 * to stop after return from ptrace_stop(). In this case it will
2431 * be checked in do_signal_stop(), we should only stop if it was
2432 * not cleared by SIGCONT while we were sleeping. See also the
2433 * comment in dequeue_signal().
2435 current
->jobctl
|= JOBCTL_STOP_DEQUEUED
;
2436 ptrace_stop(signr
, CLD_TRAPPED
, 0, info
);
2438 /* We're back. Did the debugger cancel the sig? */
2439 signr
= current
->exit_code
;
2443 current
->exit_code
= 0;
2446 * Update the siginfo structure if the signal has
2447 * changed. If the debugger wanted something
2448 * specific in the siginfo structure then it should
2449 * have updated *info via PTRACE_SETSIGINFO.
2451 if (signr
!= info
->si_signo
) {
2452 clear_siginfo(info
);
2453 info
->si_signo
= signr
;
2455 info
->si_code
= SI_USER
;
2457 info
->si_pid
= task_pid_vnr(current
->parent
);
2458 info
->si_uid
= from_kuid_munged(current_user_ns(),
2459 task_uid(current
->parent
));
2463 /* If the (new) signal is now blocked, requeue it. */
2464 if (sigismember(¤t
->blocked
, signr
)) {
2465 send_signal(signr
, info
, current
, PIDTYPE_PID
);
2472 bool get_signal(struct ksignal
*ksig
)
2474 struct sighand_struct
*sighand
= current
->sighand
;
2475 struct signal_struct
*signal
= current
->signal
;
2478 if (unlikely(current
->task_works
))
2481 if (unlikely(uprobe_deny_signal()))
2485 * Do this once, we can't return to user-mode if freezing() == T.
2486 * do_signal_stop() and ptrace_stop() do freezable_schedule() and
2487 * thus do not need another check after return.
2492 spin_lock_irq(&sighand
->siglock
);
2494 * Every stopped thread goes here after wakeup. Check to see if
2495 * we should notify the parent, prepare_signal(SIGCONT) encodes
2496 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
2498 if (unlikely(signal
->flags
& SIGNAL_CLD_MASK
)) {
2501 if (signal
->flags
& SIGNAL_CLD_CONTINUED
)
2502 why
= CLD_CONTINUED
;
2506 signal
->flags
&= ~SIGNAL_CLD_MASK
;
2508 spin_unlock_irq(&sighand
->siglock
);
2511 * Notify the parent that we're continuing. This event is
2512 * always per-process and doesn't make whole lot of sense
2513 * for ptracers, who shouldn't consume the state via
2514 * wait(2) either, but, for backward compatibility, notify
2515 * the ptracer of the group leader too unless it's gonna be
2518 read_lock(&tasklist_lock
);
2519 do_notify_parent_cldstop(current
, false, why
);
2521 if (ptrace_reparented(current
->group_leader
))
2522 do_notify_parent_cldstop(current
->group_leader
,
2524 read_unlock(&tasklist_lock
);
2529 /* Has this task already been marked for death? */
2530 if (signal_group_exit(signal
)) {
2531 ksig
->info
.si_signo
= signr
= SIGKILL
;
2532 sigdelset(¤t
->pending
.signal
, SIGKILL
);
2533 recalc_sigpending();
2538 struct k_sigaction
*ka
;
2540 if (unlikely(current
->jobctl
& JOBCTL_STOP_PENDING
) &&
2544 if (unlikely(current
->jobctl
&
2545 (JOBCTL_TRAP_MASK
| JOBCTL_TRAP_FREEZE
))) {
2546 if (current
->jobctl
& JOBCTL_TRAP_MASK
) {
2548 spin_unlock_irq(&sighand
->siglock
);
2549 } else if (current
->jobctl
& JOBCTL_TRAP_FREEZE
)
2556 * If the task is leaving the frozen state, let's update
2557 * cgroup counters and reset the frozen bit.
2559 if (unlikely(cgroup_task_frozen(current
))) {
2560 spin_unlock_irq(&sighand
->siglock
);
2561 cgroup_leave_frozen(false);
2566 * Signals generated by the execution of an instruction
2567 * need to be delivered before any other pending signals
2568 * so that the instruction pointer in the signal stack
2569 * frame points to the faulting instruction.
2571 signr
= dequeue_synchronous_signal(&ksig
->info
);
2573 signr
= dequeue_signal(current
, ¤t
->blocked
, &ksig
->info
);
2576 break; /* will return 0 */
2578 if (unlikely(current
->ptrace
) && signr
!= SIGKILL
) {
2579 signr
= ptrace_signal(signr
, &ksig
->info
);
2584 ka
= &sighand
->action
[signr
-1];
2586 /* Trace actually delivered signals. */
2587 trace_signal_deliver(signr
, &ksig
->info
, ka
);
2589 if (ka
->sa
.sa_handler
== SIG_IGN
) /* Do nothing. */
2591 if (ka
->sa
.sa_handler
!= SIG_DFL
) {
2592 /* Run the handler. */
2595 if (ka
->sa
.sa_flags
& SA_ONESHOT
)
2596 ka
->sa
.sa_handler
= SIG_DFL
;
2598 break; /* will return non-zero "signr" value */
2602 * Now we are doing the default action for this signal.
2604 if (sig_kernel_ignore(signr
)) /* Default is nothing. */
2608 * Global init gets no signals it doesn't want.
2609 * Container-init gets no signals it doesn't want from same
2612 * Note that if global/container-init sees a sig_kernel_only()
2613 * signal here, the signal must have been generated internally
2614 * or must have come from an ancestor namespace. In either
2615 * case, the signal cannot be dropped.
2617 if (unlikely(signal
->flags
& SIGNAL_UNKILLABLE
) &&
2618 !sig_kernel_only(signr
))
2621 if (sig_kernel_stop(signr
)) {
2623 * The default action is to stop all threads in
2624 * the thread group. The job control signals
2625 * do nothing in an orphaned pgrp, but SIGSTOP
2626 * always works. Note that siglock needs to be
2627 * dropped during the call to is_orphaned_pgrp()
2628 * because of lock ordering with tasklist_lock.
2629 * This allows an intervening SIGCONT to be posted.
2630 * We need to check for that and bail out if necessary.
2632 if (signr
!= SIGSTOP
) {
2633 spin_unlock_irq(&sighand
->siglock
);
2635 /* signals can be posted during this window */
2637 if (is_current_pgrp_orphaned())
2640 spin_lock_irq(&sighand
->siglock
);
2643 if (likely(do_signal_stop(ksig
->info
.si_signo
))) {
2644 /* It released the siglock. */
2649 * We didn't actually stop, due to a race
2650 * with SIGCONT or something like that.
2656 spin_unlock_irq(&sighand
->siglock
);
2657 if (unlikely(cgroup_task_frozen(current
)))
2658 cgroup_leave_frozen(true);
2661 * Anything else is fatal, maybe with a core dump.
2663 current
->flags
|= PF_SIGNALED
;
2665 if (sig_kernel_coredump(signr
)) {
2666 if (print_fatal_signals
)
2667 print_fatal_signal(ksig
->info
.si_signo
);
2668 proc_coredump_connector(current
);
2670 * If it was able to dump core, this kills all
2671 * other threads in the group and synchronizes with
2672 * their demise. If we lost the race with another
2673 * thread getting here, it set group_exit_code
2674 * first and our do_group_exit call below will use
2675 * that value and ignore the one we pass it.
2677 do_coredump(&ksig
->info
);
2681 * Death signals, no core dump.
2683 do_group_exit(ksig
->info
.si_signo
);
2686 spin_unlock_irq(&sighand
->siglock
);
2689 return ksig
->sig
> 0;
2693 * signal_delivered -
2694 * @ksig: kernel signal struct
2695 * @stepping: nonzero if debugger single-step or block-step in use
2697 * This function should be called when a signal has successfully been
2698 * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
2699 * is always blocked, and the signal itself is blocked unless %SA_NODEFER
2700 * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
2702 static void signal_delivered(struct ksignal
*ksig
, int stepping
)
2706 /* A signal was successfully delivered, and the
2707 saved sigmask was stored on the signal frame,
2708 and will be restored by sigreturn. So we can
2709 simply clear the restore sigmask flag. */
2710 clear_restore_sigmask();
2712 sigorsets(&blocked
, ¤t
->blocked
, &ksig
->ka
.sa
.sa_mask
);
2713 if (!(ksig
->ka
.sa
.sa_flags
& SA_NODEFER
))
2714 sigaddset(&blocked
, ksig
->sig
);
2715 set_current_blocked(&blocked
);
2716 tracehook_signal_handler(stepping
);
2719 void signal_setup_done(int failed
, struct ksignal
*ksig
, int stepping
)
2722 force_sigsegv(ksig
->sig
);
2724 signal_delivered(ksig
, stepping
);
2728 * It could be that complete_signal() picked us to notify about the
2729 * group-wide signal. Other threads should be notified now to take
2730 * the shared signals in @which since we will not.
2732 static void retarget_shared_pending(struct task_struct
*tsk
, sigset_t
*which
)
2735 struct task_struct
*t
;
2737 sigandsets(&retarget
, &tsk
->signal
->shared_pending
.signal
, which
);
2738 if (sigisemptyset(&retarget
))
2742 while_each_thread(tsk
, t
) {
2743 if (t
->flags
& PF_EXITING
)
2746 if (!has_pending_signals(&retarget
, &t
->blocked
))
2748 /* Remove the signals this thread can handle. */
2749 sigandsets(&retarget
, &retarget
, &t
->blocked
);
2751 if (!signal_pending(t
))
2752 signal_wake_up(t
, 0);
2754 if (sigisemptyset(&retarget
))
2759 void exit_signals(struct task_struct
*tsk
)
2765 * @tsk is about to have PF_EXITING set - lock out users which
2766 * expect stable threadgroup.
2768 cgroup_threadgroup_change_begin(tsk
);
2770 if (thread_group_empty(tsk
) || signal_group_exit(tsk
->signal
)) {
2771 tsk
->flags
|= PF_EXITING
;
2772 cgroup_threadgroup_change_end(tsk
);
2776 spin_lock_irq(&tsk
->sighand
->siglock
);
2778 * From now this task is not visible for group-wide signals,
2779 * see wants_signal(), do_signal_stop().
2781 tsk
->flags
|= PF_EXITING
;
2783 cgroup_threadgroup_change_end(tsk
);
2785 if (!signal_pending(tsk
))
2788 unblocked
= tsk
->blocked
;
2789 signotset(&unblocked
);
2790 retarget_shared_pending(tsk
, &unblocked
);
2792 if (unlikely(tsk
->jobctl
& JOBCTL_STOP_PENDING
) &&
2793 task_participate_group_stop(tsk
))
2794 group_stop
= CLD_STOPPED
;
2796 spin_unlock_irq(&tsk
->sighand
->siglock
);
2799 * If group stop has completed, deliver the notification. This
2800 * should always go to the real parent of the group leader.
2802 if (unlikely(group_stop
)) {
2803 read_lock(&tasklist_lock
);
2804 do_notify_parent_cldstop(tsk
, false, group_stop
);
2805 read_unlock(&tasklist_lock
);
2810 * System call entry points.
2814 * sys_restart_syscall - restart a system call
2816 SYSCALL_DEFINE0(restart_syscall
)
2818 struct restart_block
*restart
= ¤t
->restart_block
;
2819 return restart
->fn(restart
);
2822 long do_no_restart_syscall(struct restart_block
*param
)
2827 static void __set_task_blocked(struct task_struct
*tsk
, const sigset_t
*newset
)
2829 if (signal_pending(tsk
) && !thread_group_empty(tsk
)) {
2830 sigset_t newblocked
;
2831 /* A set of now blocked but previously unblocked signals. */
2832 sigandnsets(&newblocked
, newset
, ¤t
->blocked
);
2833 retarget_shared_pending(tsk
, &newblocked
);
2835 tsk
->blocked
= *newset
;
2836 recalc_sigpending();
2840 * set_current_blocked - change current->blocked mask
2843 * It is wrong to change ->blocked directly, this helper should be used
2844 * to ensure the process can't miss a shared signal we are going to block.
2846 void set_current_blocked(sigset_t
*newset
)
2848 sigdelsetmask(newset
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
2849 __set_current_blocked(newset
);
2852 void __set_current_blocked(const sigset_t
*newset
)
2854 struct task_struct
*tsk
= current
;
2857 * In case the signal mask hasn't changed, there is nothing we need
2858 * to do. The current->blocked shouldn't be modified by other task.
2860 if (sigequalsets(&tsk
->blocked
, newset
))
2863 spin_lock_irq(&tsk
->sighand
->siglock
);
2864 __set_task_blocked(tsk
, newset
);
2865 spin_unlock_irq(&tsk
->sighand
->siglock
);
2869 * This is also useful for kernel threads that want to temporarily
2870 * (or permanently) block certain signals.
2872 * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel
2873 * interface happily blocks "unblockable" signals like SIGKILL
2876 int sigprocmask(int how
, sigset_t
*set
, sigset_t
*oldset
)
2878 struct task_struct
*tsk
= current
;
2881 /* Lockless, only current can change ->blocked, never from irq */
2883 *oldset
= tsk
->blocked
;
2887 sigorsets(&newset
, &tsk
->blocked
, set
);
2890 sigandnsets(&newset
, &tsk
->blocked
, set
);
2899 __set_current_blocked(&newset
);
2902 EXPORT_SYMBOL(sigprocmask
);
2905 * The api helps set app-provided sigmasks.
2907 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2908 * epoll_pwait where a new sigmask is passed from userland for the syscalls.
2910 int set_user_sigmask(const sigset_t __user
*usigmask
, sigset_t
*set
,
2911 sigset_t
*oldset
, size_t sigsetsize
)
2916 if (sigsetsize
!= sizeof(sigset_t
))
2918 if (copy_from_user(set
, usigmask
, sizeof(sigset_t
)))
2921 *oldset
= current
->blocked
;
2922 set_current_blocked(set
);
2926 EXPORT_SYMBOL(set_user_sigmask
);
2928 #ifdef CONFIG_COMPAT
2929 int set_compat_user_sigmask(const compat_sigset_t __user
*usigmask
,
2930 sigset_t
*set
, sigset_t
*oldset
,
2936 if (sigsetsize
!= sizeof(compat_sigset_t
))
2938 if (get_compat_sigset(set
, usigmask
))
2941 *oldset
= current
->blocked
;
2942 set_current_blocked(set
);
2946 EXPORT_SYMBOL(set_compat_user_sigmask
);
2950 * restore_user_sigmask:
2951 * usigmask: sigmask passed in from userland.
2952 * sigsaved: saved sigmask when the syscall started and changed the sigmask to
2955 * This is useful for syscalls such as ppoll, pselect, io_pgetevents and
2956 * epoll_pwait where a new sigmask is passed in from userland for the syscalls.
2958 void restore_user_sigmask(const void __user
*usigmask
, sigset_t
*sigsaved
)
2964 * When signals are pending, do not restore them here.
2965 * Restoring sigmask here can lead to delivering signals that the above
2966 * syscalls are intended to block because of the sigmask passed in.
2968 if (signal_pending(current
)) {
2969 current
->saved_sigmask
= *sigsaved
;
2970 set_restore_sigmask();
2975 * This is needed because the fast syscall return path does not restore
2976 * saved_sigmask when signals are not pending.
2978 set_current_blocked(sigsaved
);
2980 EXPORT_SYMBOL(restore_user_sigmask
);
2983 * sys_rt_sigprocmask - change the list of currently blocked signals
2984 * @how: whether to add, remove, or set signals
2985 * @nset: stores pending signals
2986 * @oset: previous value of signal mask if non-null
2987 * @sigsetsize: size of sigset_t type
2989 SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, sigset_t __user
*, nset
,
2990 sigset_t __user
*, oset
, size_t, sigsetsize
)
2992 sigset_t old_set
, new_set
;
2995 /* XXX: Don't preclude handling different sized sigset_t's. */
2996 if (sigsetsize
!= sizeof(sigset_t
))
2999 old_set
= current
->blocked
;
3002 if (copy_from_user(&new_set
, nset
, sizeof(sigset_t
)))
3004 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
3006 error
= sigprocmask(how
, &new_set
, NULL
);
3012 if (copy_to_user(oset
, &old_set
, sizeof(sigset_t
)))
3019 #ifdef CONFIG_COMPAT
3020 COMPAT_SYSCALL_DEFINE4(rt_sigprocmask
, int, how
, compat_sigset_t __user
*, nset
,
3021 compat_sigset_t __user
*, oset
, compat_size_t
, sigsetsize
)
3023 sigset_t old_set
= current
->blocked
;
3025 /* XXX: Don't preclude handling different sized sigset_t's. */
3026 if (sigsetsize
!= sizeof(sigset_t
))
3032 if (get_compat_sigset(&new_set
, nset
))
3034 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
3036 error
= sigprocmask(how
, &new_set
, NULL
);
3040 return oset
? put_compat_sigset(oset
, &old_set
, sizeof(*oset
)) : 0;
3044 static void do_sigpending(sigset_t
*set
)
3046 spin_lock_irq(¤t
->sighand
->siglock
);
3047 sigorsets(set
, ¤t
->pending
.signal
,
3048 ¤t
->signal
->shared_pending
.signal
);
3049 spin_unlock_irq(¤t
->sighand
->siglock
);
3051 /* Outside the lock because only this thread touches it. */
3052 sigandsets(set
, ¤t
->blocked
, set
);
3056 * sys_rt_sigpending - examine a pending signal that has been raised
3058 * @uset: stores pending signals
3059 * @sigsetsize: size of sigset_t type or larger
3061 SYSCALL_DEFINE2(rt_sigpending
, sigset_t __user
*, uset
, size_t, sigsetsize
)
3065 if (sigsetsize
> sizeof(*uset
))
3068 do_sigpending(&set
);
3070 if (copy_to_user(uset
, &set
, sigsetsize
))
3076 #ifdef CONFIG_COMPAT
3077 COMPAT_SYSCALL_DEFINE2(rt_sigpending
, compat_sigset_t __user
*, uset
,
3078 compat_size_t
, sigsetsize
)
3082 if (sigsetsize
> sizeof(*uset
))
3085 do_sigpending(&set
);
3087 return put_compat_sigset(uset
, &set
, sigsetsize
);
3091 static const struct {
3092 unsigned char limit
, layout
;
3094 [SIGILL
] = { NSIGILL
, SIL_FAULT
},
3095 [SIGFPE
] = { NSIGFPE
, SIL_FAULT
},
3096 [SIGSEGV
] = { NSIGSEGV
, SIL_FAULT
},
3097 [SIGBUS
] = { NSIGBUS
, SIL_FAULT
},
3098 [SIGTRAP
] = { NSIGTRAP
, SIL_FAULT
},
3100 [SIGEMT
] = { NSIGEMT
, SIL_FAULT
},
3102 [SIGCHLD
] = { NSIGCHLD
, SIL_CHLD
},
3103 [SIGPOLL
] = { NSIGPOLL
, SIL_POLL
},
3104 [SIGSYS
] = { NSIGSYS
, SIL_SYS
},
3107 static bool known_siginfo_layout(unsigned sig
, int si_code
)
3109 if (si_code
== SI_KERNEL
)
3111 else if ((si_code
> SI_USER
)) {
3112 if (sig_specific_sicodes(sig
)) {
3113 if (si_code
<= sig_sicodes
[sig
].limit
)
3116 else if (si_code
<= NSIGPOLL
)
3119 else if (si_code
>= SI_DETHREAD
)
3121 else if (si_code
== SI_ASYNCNL
)
3126 enum siginfo_layout
siginfo_layout(unsigned sig
, int si_code
)
3128 enum siginfo_layout layout
= SIL_KILL
;
3129 if ((si_code
> SI_USER
) && (si_code
< SI_KERNEL
)) {
3130 if ((sig
< ARRAY_SIZE(sig_sicodes
)) &&
3131 (si_code
<= sig_sicodes
[sig
].limit
)) {
3132 layout
= sig_sicodes
[sig
].layout
;
3133 /* Handle the exceptions */
3134 if ((sig
== SIGBUS
) &&
3135 (si_code
>= BUS_MCEERR_AR
) && (si_code
<= BUS_MCEERR_AO
))
3136 layout
= SIL_FAULT_MCEERR
;
3137 else if ((sig
== SIGSEGV
) && (si_code
== SEGV_BNDERR
))
3138 layout
= SIL_FAULT_BNDERR
;
3140 else if ((sig
== SIGSEGV
) && (si_code
== SEGV_PKUERR
))
3141 layout
= SIL_FAULT_PKUERR
;
3144 else if (si_code
<= NSIGPOLL
)
3147 if (si_code
== SI_TIMER
)
3149 else if (si_code
== SI_SIGIO
)
3151 else if (si_code
< 0)
3157 static inline char __user
*si_expansion(const siginfo_t __user
*info
)
3159 return ((char __user
*)info
) + sizeof(struct kernel_siginfo
);
3162 int copy_siginfo_to_user(siginfo_t __user
*to
, const kernel_siginfo_t
*from
)
3164 char __user
*expansion
= si_expansion(to
);
3165 if (copy_to_user(to
, from
, sizeof(struct kernel_siginfo
)))
3167 if (clear_user(expansion
, SI_EXPANSION_SIZE
))
3172 static int post_copy_siginfo_from_user(kernel_siginfo_t
*info
,
3173 const siginfo_t __user
*from
)
3175 if (unlikely(!known_siginfo_layout(info
->si_signo
, info
->si_code
))) {
3176 char __user
*expansion
= si_expansion(from
);
3177 char buf
[SI_EXPANSION_SIZE
];
3180 * An unknown si_code might need more than
3181 * sizeof(struct kernel_siginfo) bytes. Verify all of the
3182 * extra bytes are 0. This guarantees copy_siginfo_to_user
3183 * will return this data to userspace exactly.
3185 if (copy_from_user(&buf
, expansion
, SI_EXPANSION_SIZE
))
3187 for (i
= 0; i
< SI_EXPANSION_SIZE
; i
++) {
3195 static int __copy_siginfo_from_user(int signo
, kernel_siginfo_t
*to
,
3196 const siginfo_t __user
*from
)
3198 if (copy_from_user(to
, from
, sizeof(struct kernel_siginfo
)))
3200 to
->si_signo
= signo
;
3201 return post_copy_siginfo_from_user(to
, from
);
3204 int copy_siginfo_from_user(kernel_siginfo_t
*to
, const siginfo_t __user
*from
)
3206 if (copy_from_user(to
, from
, sizeof(struct kernel_siginfo
)))
3208 return post_copy_siginfo_from_user(to
, from
);
3211 #ifdef CONFIG_COMPAT
3212 int copy_siginfo_to_user32(struct compat_siginfo __user
*to
,
3213 const struct kernel_siginfo
*from
)
3214 #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
3216 return __copy_siginfo_to_user32(to
, from
, in_x32_syscall());
3218 int __copy_siginfo_to_user32(struct compat_siginfo __user
*to
,
3219 const struct kernel_siginfo
*from
, bool x32_ABI
)
3222 struct compat_siginfo
new;
3223 memset(&new, 0, sizeof(new));
3225 new.si_signo
= from
->si_signo
;
3226 new.si_errno
= from
->si_errno
;
3227 new.si_code
= from
->si_code
;
3228 switch(siginfo_layout(from
->si_signo
, from
->si_code
)) {
3230 new.si_pid
= from
->si_pid
;
3231 new.si_uid
= from
->si_uid
;
3234 new.si_tid
= from
->si_tid
;
3235 new.si_overrun
= from
->si_overrun
;
3236 new.si_int
= from
->si_int
;
3239 new.si_band
= from
->si_band
;
3240 new.si_fd
= from
->si_fd
;
3243 new.si_addr
= ptr_to_compat(from
->si_addr
);
3244 #ifdef __ARCH_SI_TRAPNO
3245 new.si_trapno
= from
->si_trapno
;
3248 case SIL_FAULT_MCEERR
:
3249 new.si_addr
= ptr_to_compat(from
->si_addr
);
3250 #ifdef __ARCH_SI_TRAPNO
3251 new.si_trapno
= from
->si_trapno
;
3253 new.si_addr_lsb
= from
->si_addr_lsb
;
3255 case SIL_FAULT_BNDERR
:
3256 new.si_addr
= ptr_to_compat(from
->si_addr
);
3257 #ifdef __ARCH_SI_TRAPNO
3258 new.si_trapno
= from
->si_trapno
;
3260 new.si_lower
= ptr_to_compat(from
->si_lower
);
3261 new.si_upper
= ptr_to_compat(from
->si_upper
);
3263 case SIL_FAULT_PKUERR
:
3264 new.si_addr
= ptr_to_compat(from
->si_addr
);
3265 #ifdef __ARCH_SI_TRAPNO
3266 new.si_trapno
= from
->si_trapno
;
3268 new.si_pkey
= from
->si_pkey
;
3271 new.si_pid
= from
->si_pid
;
3272 new.si_uid
= from
->si_uid
;
3273 new.si_status
= from
->si_status
;
3274 #ifdef CONFIG_X86_X32_ABI
3276 new._sifields
._sigchld_x32
._utime
= from
->si_utime
;
3277 new._sifields
._sigchld_x32
._stime
= from
->si_stime
;
3281 new.si_utime
= from
->si_utime
;
3282 new.si_stime
= from
->si_stime
;
3286 new.si_pid
= from
->si_pid
;
3287 new.si_uid
= from
->si_uid
;
3288 new.si_int
= from
->si_int
;
3291 new.si_call_addr
= ptr_to_compat(from
->si_call_addr
);
3292 new.si_syscall
= from
->si_syscall
;
3293 new.si_arch
= from
->si_arch
;
3297 if (copy_to_user(to
, &new, sizeof(struct compat_siginfo
)))
3303 static int post_copy_siginfo_from_user32(kernel_siginfo_t
*to
,
3304 const struct compat_siginfo
*from
)
3307 to
->si_signo
= from
->si_signo
;
3308 to
->si_errno
= from
->si_errno
;
3309 to
->si_code
= from
->si_code
;
3310 switch(siginfo_layout(from
->si_signo
, from
->si_code
)) {
3312 to
->si_pid
= from
->si_pid
;
3313 to
->si_uid
= from
->si_uid
;
3316 to
->si_tid
= from
->si_tid
;
3317 to
->si_overrun
= from
->si_overrun
;
3318 to
->si_int
= from
->si_int
;
3321 to
->si_band
= from
->si_band
;
3322 to
->si_fd
= from
->si_fd
;
3325 to
->si_addr
= compat_ptr(from
->si_addr
);
3326 #ifdef __ARCH_SI_TRAPNO
3327 to
->si_trapno
= from
->si_trapno
;
3330 case SIL_FAULT_MCEERR
:
3331 to
->si_addr
= compat_ptr(from
->si_addr
);
3332 #ifdef __ARCH_SI_TRAPNO
3333 to
->si_trapno
= from
->si_trapno
;
3335 to
->si_addr_lsb
= from
->si_addr_lsb
;
3337 case SIL_FAULT_BNDERR
:
3338 to
->si_addr
= compat_ptr(from
->si_addr
);
3339 #ifdef __ARCH_SI_TRAPNO
3340 to
->si_trapno
= from
->si_trapno
;
3342 to
->si_lower
= compat_ptr(from
->si_lower
);
3343 to
->si_upper
= compat_ptr(from
->si_upper
);
3345 case SIL_FAULT_PKUERR
:
3346 to
->si_addr
= compat_ptr(from
->si_addr
);
3347 #ifdef __ARCH_SI_TRAPNO
3348 to
->si_trapno
= from
->si_trapno
;
3350 to
->si_pkey
= from
->si_pkey
;
3353 to
->si_pid
= from
->si_pid
;
3354 to
->si_uid
= from
->si_uid
;
3355 to
->si_status
= from
->si_status
;
3356 #ifdef CONFIG_X86_X32_ABI
3357 if (in_x32_syscall()) {
3358 to
->si_utime
= from
->_sifields
._sigchld_x32
._utime
;
3359 to
->si_stime
= from
->_sifields
._sigchld_x32
._stime
;
3363 to
->si_utime
= from
->si_utime
;
3364 to
->si_stime
= from
->si_stime
;
3368 to
->si_pid
= from
->si_pid
;
3369 to
->si_uid
= from
->si_uid
;
3370 to
->si_int
= from
->si_int
;
3373 to
->si_call_addr
= compat_ptr(from
->si_call_addr
);
3374 to
->si_syscall
= from
->si_syscall
;
3375 to
->si_arch
= from
->si_arch
;
3381 static int __copy_siginfo_from_user32(int signo
, struct kernel_siginfo
*to
,
3382 const struct compat_siginfo __user
*ufrom
)
3384 struct compat_siginfo from
;
3386 if (copy_from_user(&from
, ufrom
, sizeof(struct compat_siginfo
)))
3389 from
.si_signo
= signo
;
3390 return post_copy_siginfo_from_user32(to
, &from
);
3393 int copy_siginfo_from_user32(struct kernel_siginfo
*to
,
3394 const struct compat_siginfo __user
*ufrom
)
3396 struct compat_siginfo from
;
3398 if (copy_from_user(&from
, ufrom
, sizeof(struct compat_siginfo
)))
3401 return post_copy_siginfo_from_user32(to
, &from
);
3403 #endif /* CONFIG_COMPAT */
3406 * do_sigtimedwait - wait for queued signals specified in @which
3407 * @which: queued signals to wait for
3408 * @info: if non-null, the signal's siginfo is returned here
3409 * @ts: upper bound on process time suspension
3411 static int do_sigtimedwait(const sigset_t
*which
, kernel_siginfo_t
*info
,
3412 const struct timespec64
*ts
)
3414 ktime_t
*to
= NULL
, timeout
= KTIME_MAX
;
3415 struct task_struct
*tsk
= current
;
3416 sigset_t mask
= *which
;
3420 if (!timespec64_valid(ts
))
3422 timeout
= timespec64_to_ktime(*ts
);
3427 * Invert the set of allowed signals to get those we want to block.
3429 sigdelsetmask(&mask
, sigmask(SIGKILL
) | sigmask(SIGSTOP
));
3432 spin_lock_irq(&tsk
->sighand
->siglock
);
3433 sig
= dequeue_signal(tsk
, &mask
, info
);
3434 if (!sig
&& timeout
) {
3436 * None ready, temporarily unblock those we're interested
3437 * while we are sleeping in so that we'll be awakened when
3438 * they arrive. Unblocking is always fine, we can avoid
3439 * set_current_blocked().
3441 tsk
->real_blocked
= tsk
->blocked
;
3442 sigandsets(&tsk
->blocked
, &tsk
->blocked
, &mask
);
3443 recalc_sigpending();
3444 spin_unlock_irq(&tsk
->sighand
->siglock
);
3446 __set_current_state(TASK_INTERRUPTIBLE
);
3447 ret
= freezable_schedule_hrtimeout_range(to
, tsk
->timer_slack_ns
,
3449 spin_lock_irq(&tsk
->sighand
->siglock
);
3450 __set_task_blocked(tsk
, &tsk
->real_blocked
);
3451 sigemptyset(&tsk
->real_blocked
);
3452 sig
= dequeue_signal(tsk
, &mask
, info
);
3454 spin_unlock_irq(&tsk
->sighand
->siglock
);
3458 return ret
? -EINTR
: -EAGAIN
;
3462 * sys_rt_sigtimedwait - synchronously wait for queued signals specified
3464 * @uthese: queued signals to wait for
3465 * @uinfo: if non-null, the signal's siginfo is returned here
3466 * @uts: upper bound on process time suspension
3467 * @sigsetsize: size of sigset_t type
3469 SYSCALL_DEFINE4(rt_sigtimedwait
, const sigset_t __user
*, uthese
,
3470 siginfo_t __user
*, uinfo
,
3471 const struct __kernel_timespec __user
*, uts
,
3475 struct timespec64 ts
;
3476 kernel_siginfo_t info
;
3479 /* XXX: Don't preclude handling different sized sigset_t's. */
3480 if (sigsetsize
!= sizeof(sigset_t
))
3483 if (copy_from_user(&these
, uthese
, sizeof(these
)))
3487 if (get_timespec64(&ts
, uts
))
3491 ret
= do_sigtimedwait(&these
, &info
, uts
? &ts
: NULL
);
3493 if (ret
> 0 && uinfo
) {
3494 if (copy_siginfo_to_user(uinfo
, &info
))
3501 #ifdef CONFIG_COMPAT_32BIT_TIME
3502 SYSCALL_DEFINE4(rt_sigtimedwait_time32
, const sigset_t __user
*, uthese
,
3503 siginfo_t __user
*, uinfo
,
3504 const struct old_timespec32 __user
*, uts
,
3508 struct timespec64 ts
;
3509 kernel_siginfo_t info
;
3512 if (sigsetsize
!= sizeof(sigset_t
))
3515 if (copy_from_user(&these
, uthese
, sizeof(these
)))
3519 if (get_old_timespec32(&ts
, uts
))
3523 ret
= do_sigtimedwait(&these
, &info
, uts
? &ts
: NULL
);
3525 if (ret
> 0 && uinfo
) {
3526 if (copy_siginfo_to_user(uinfo
, &info
))
3534 #ifdef CONFIG_COMPAT
3535 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time64
, compat_sigset_t __user
*, uthese
,
3536 struct compat_siginfo __user
*, uinfo
,
3537 struct __kernel_timespec __user
*, uts
, compat_size_t
, sigsetsize
)
3540 struct timespec64 t
;
3541 kernel_siginfo_t info
;
3544 if (sigsetsize
!= sizeof(sigset_t
))
3547 if (get_compat_sigset(&s
, uthese
))
3551 if (get_timespec64(&t
, uts
))
3555 ret
= do_sigtimedwait(&s
, &info
, uts
? &t
: NULL
);
3557 if (ret
> 0 && uinfo
) {
3558 if (copy_siginfo_to_user32(uinfo
, &info
))
3565 #ifdef CONFIG_COMPAT_32BIT_TIME
3566 COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32
, compat_sigset_t __user
*, uthese
,
3567 struct compat_siginfo __user
*, uinfo
,
3568 struct old_timespec32 __user
*, uts
, compat_size_t
, sigsetsize
)
3571 struct timespec64 t
;
3572 kernel_siginfo_t info
;
3575 if (sigsetsize
!= sizeof(sigset_t
))
3578 if (get_compat_sigset(&s
, uthese
))
3582 if (get_old_timespec32(&t
, uts
))
3586 ret
= do_sigtimedwait(&s
, &info
, uts
? &t
: NULL
);
3588 if (ret
> 0 && uinfo
) {
3589 if (copy_siginfo_to_user32(uinfo
, &info
))
3598 static inline void prepare_kill_siginfo(int sig
, struct kernel_siginfo
*info
)
3600 clear_siginfo(info
);
3601 info
->si_signo
= sig
;
3603 info
->si_code
= SI_USER
;
3604 info
->si_pid
= task_tgid_vnr(current
);
3605 info
->si_uid
= from_kuid_munged(current_user_ns(), current_uid());
3609 * sys_kill - send a signal to a process
3610 * @pid: the PID of the process
3611 * @sig: signal to be sent
3613 SYSCALL_DEFINE2(kill
, pid_t
, pid
, int, sig
)
3615 struct kernel_siginfo info
;
3617 prepare_kill_siginfo(sig
, &info
);
3619 return kill_something_info(sig
, &info
, pid
);
3623 * Verify that the signaler and signalee either are in the same pid namespace
3624 * or that the signaler's pid namespace is an ancestor of the signalee's pid
3627 static bool access_pidfd_pidns(struct pid
*pid
)
3629 struct pid_namespace
*active
= task_active_pid_ns(current
);
3630 struct pid_namespace
*p
= ns_of_pid(pid
);
3643 static int copy_siginfo_from_user_any(kernel_siginfo_t
*kinfo
, siginfo_t
*info
)
3645 #ifdef CONFIG_COMPAT
3647 * Avoid hooking up compat syscalls and instead handle necessary
3648 * conversions here. Note, this is a stop-gap measure and should not be
3649 * considered a generic solution.
3651 if (in_compat_syscall())
3652 return copy_siginfo_from_user32(
3653 kinfo
, (struct compat_siginfo __user
*)info
);
3655 return copy_siginfo_from_user(kinfo
, info
);
3658 static struct pid
*pidfd_to_pid(const struct file
*file
)
3660 if (file
->f_op
== &pidfd_fops
)
3661 return file
->private_data
;
3663 return tgid_pidfd_to_pid(file
);
3667 * sys_pidfd_send_signal - send a signal to a process through a task file
3669 * @pidfd: the file descriptor of the process
3670 * @sig: signal to be sent
3671 * @info: the signal info
3672 * @flags: future flags to be passed
3674 * The syscall currently only signals via PIDTYPE_PID which covers
3675 * kill(<positive-pid>, <signal>. It does not signal threads or process
3677 * In order to extend the syscall to threads and process groups the @flags
3678 * argument should be used. In essence, the @flags argument will determine
3679 * what is signaled and not the file descriptor itself. Put in other words,
3680 * grouping is a property of the flags argument not a property of the file
3683 * Return: 0 on success, negative errno on failure
3685 SYSCALL_DEFINE4(pidfd_send_signal
, int, pidfd
, int, sig
,
3686 siginfo_t __user
*, info
, unsigned int, flags
)
3691 kernel_siginfo_t kinfo
;
3693 /* Enforce flags be set to 0 until we add an extension. */
3701 /* Is this a pidfd? */
3702 pid
= pidfd_to_pid(f
.file
);
3709 if (!access_pidfd_pidns(pid
))
3713 ret
= copy_siginfo_from_user_any(&kinfo
, info
);
3718 if (unlikely(sig
!= kinfo
.si_signo
))
3721 /* Only allow sending arbitrary signals to yourself. */
3723 if ((task_pid(current
) != pid
) &&
3724 (kinfo
.si_code
>= 0 || kinfo
.si_code
== SI_TKILL
))
3727 prepare_kill_siginfo(sig
, &kinfo
);
3730 ret
= kill_pid_info(sig
, &kinfo
, pid
);
3738 do_send_specific(pid_t tgid
, pid_t pid
, int sig
, struct kernel_siginfo
*info
)
3740 struct task_struct
*p
;
3744 p
= find_task_by_vpid(pid
);
3745 if (p
&& (tgid
<= 0 || task_tgid_vnr(p
) == tgid
)) {
3746 error
= check_kill_permission(sig
, info
, p
);
3748 * The null signal is a permissions and process existence
3749 * probe. No signal is actually delivered.
3751 if (!error
&& sig
) {
3752 error
= do_send_sig_info(sig
, info
, p
, PIDTYPE_PID
);
3754 * If lock_task_sighand() failed we pretend the task
3755 * dies after receiving the signal. The window is tiny,
3756 * and the signal is private anyway.
3758 if (unlikely(error
== -ESRCH
))
3767 static int do_tkill(pid_t tgid
, pid_t pid
, int sig
)
3769 struct kernel_siginfo info
;
3771 clear_siginfo(&info
);
3772 info
.si_signo
= sig
;
3774 info
.si_code
= SI_TKILL
;
3775 info
.si_pid
= task_tgid_vnr(current
);
3776 info
.si_uid
= from_kuid_munged(current_user_ns(), current_uid());
3778 return do_send_specific(tgid
, pid
, sig
, &info
);
3782 * sys_tgkill - send signal to one specific thread
3783 * @tgid: the thread group ID of the thread
3784 * @pid: the PID of the thread
3785 * @sig: signal to be sent
3787 * This syscall also checks the @tgid and returns -ESRCH even if the PID
3788 * exists but it's not belonging to the target process anymore. This
3789 * method solves the problem of threads exiting and PIDs getting reused.
3791 SYSCALL_DEFINE3(tgkill
, pid_t
, tgid
, pid_t
, pid
, int, sig
)
3793 /* This is only valid for single tasks */
3794 if (pid
<= 0 || tgid
<= 0)
3797 return do_tkill(tgid
, pid
, sig
);
3801 * sys_tkill - send signal to one specific task
3802 * @pid: the PID of the task
3803 * @sig: signal to be sent
3805 * Send a signal to only one task, even if it's a CLONE_THREAD task.
3807 SYSCALL_DEFINE2(tkill
, pid_t
, pid
, int, sig
)
3809 /* This is only valid for single tasks */
3813 return do_tkill(0, pid
, sig
);
3816 static int do_rt_sigqueueinfo(pid_t pid
, int sig
, kernel_siginfo_t
*info
)
3818 /* Not even root can pretend to send signals from the kernel.
3819 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3821 if ((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
) &&
3822 (task_pid_vnr(current
) != pid
))
3825 /* POSIX.1b doesn't mention process groups. */
3826 return kill_proc_info(sig
, info
, pid
);
3830 * sys_rt_sigqueueinfo - send signal information to a signal
3831 * @pid: the PID of the thread
3832 * @sig: signal to be sent
3833 * @uinfo: signal info to be sent
3835 SYSCALL_DEFINE3(rt_sigqueueinfo
, pid_t
, pid
, int, sig
,
3836 siginfo_t __user
*, uinfo
)
3838 kernel_siginfo_t info
;
3839 int ret
= __copy_siginfo_from_user(sig
, &info
, uinfo
);
3842 return do_rt_sigqueueinfo(pid
, sig
, &info
);
3845 #ifdef CONFIG_COMPAT
3846 COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo
,
3849 struct compat_siginfo __user
*, uinfo
)
3851 kernel_siginfo_t info
;
3852 int ret
= __copy_siginfo_from_user32(sig
, &info
, uinfo
);
3855 return do_rt_sigqueueinfo(pid
, sig
, &info
);
3859 static int do_rt_tgsigqueueinfo(pid_t tgid
, pid_t pid
, int sig
, kernel_siginfo_t
*info
)
3861 /* This is only valid for single tasks */
3862 if (pid
<= 0 || tgid
<= 0)
3865 /* Not even root can pretend to send signals from the kernel.
3866 * Nor can they impersonate a kill()/tgkill(), which adds source info.
3868 if ((info
->si_code
>= 0 || info
->si_code
== SI_TKILL
) &&
3869 (task_pid_vnr(current
) != pid
))
3872 return do_send_specific(tgid
, pid
, sig
, info
);
3875 SYSCALL_DEFINE4(rt_tgsigqueueinfo
, pid_t
, tgid
, pid_t
, pid
, int, sig
,
3876 siginfo_t __user
*, uinfo
)
3878 kernel_siginfo_t info
;
3879 int ret
= __copy_siginfo_from_user(sig
, &info
, uinfo
);
3882 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
3885 #ifdef CONFIG_COMPAT
3886 COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo
,
3890 struct compat_siginfo __user
*, uinfo
)
3892 kernel_siginfo_t info
;
3893 int ret
= __copy_siginfo_from_user32(sig
, &info
, uinfo
);
3896 return do_rt_tgsigqueueinfo(tgid
, pid
, sig
, &info
);
3901 * For kthreads only, must not be used if cloned with CLONE_SIGHAND
3903 void kernel_sigaction(int sig
, __sighandler_t action
)
3905 spin_lock_irq(¤t
->sighand
->siglock
);
3906 current
->sighand
->action
[sig
- 1].sa
.sa_handler
= action
;
3907 if (action
== SIG_IGN
) {
3911 sigaddset(&mask
, sig
);
3913 flush_sigqueue_mask(&mask
, ¤t
->signal
->shared_pending
);
3914 flush_sigqueue_mask(&mask
, ¤t
->pending
);
3915 recalc_sigpending();
3917 spin_unlock_irq(¤t
->sighand
->siglock
);
3919 EXPORT_SYMBOL(kernel_sigaction
);
3921 void __weak
sigaction_compat_abi(struct k_sigaction
*act
,
3922 struct k_sigaction
*oact
)
3926 int do_sigaction(int sig
, struct k_sigaction
*act
, struct k_sigaction
*oact
)
3928 struct task_struct
*p
= current
, *t
;
3929 struct k_sigaction
*k
;
3932 if (!valid_signal(sig
) || sig
< 1 || (act
&& sig_kernel_only(sig
)))
3935 k
= &p
->sighand
->action
[sig
-1];
3937 spin_lock_irq(&p
->sighand
->siglock
);
3941 sigaction_compat_abi(act
, oact
);
3944 sigdelsetmask(&act
->sa
.sa_mask
,
3945 sigmask(SIGKILL
) | sigmask(SIGSTOP
));
3949 * "Setting a signal action to SIG_IGN for a signal that is
3950 * pending shall cause the pending signal to be discarded,
3951 * whether or not it is blocked."
3953 * "Setting a signal action to SIG_DFL for a signal that is
3954 * pending and whose default action is to ignore the signal
3955 * (for example, SIGCHLD), shall cause the pending signal to
3956 * be discarded, whether or not it is blocked"
3958 if (sig_handler_ignored(sig_handler(p
, sig
), sig
)) {
3960 sigaddset(&mask
, sig
);
3961 flush_sigqueue_mask(&mask
, &p
->signal
->shared_pending
);
3962 for_each_thread(p
, t
)
3963 flush_sigqueue_mask(&mask
, &t
->pending
);
3967 spin_unlock_irq(&p
->sighand
->siglock
);
3972 do_sigaltstack (const stack_t
*ss
, stack_t
*oss
, unsigned long sp
,
3975 struct task_struct
*t
= current
;
3978 memset(oss
, 0, sizeof(stack_t
));
3979 oss
->ss_sp
= (void __user
*) t
->sas_ss_sp
;
3980 oss
->ss_size
= t
->sas_ss_size
;
3981 oss
->ss_flags
= sas_ss_flags(sp
) |
3982 (current
->sas_ss_flags
& SS_FLAG_BITS
);
3986 void __user
*ss_sp
= ss
->ss_sp
;
3987 size_t ss_size
= ss
->ss_size
;
3988 unsigned ss_flags
= ss
->ss_flags
;
3991 if (unlikely(on_sig_stack(sp
)))
3994 ss_mode
= ss_flags
& ~SS_FLAG_BITS
;
3995 if (unlikely(ss_mode
!= SS_DISABLE
&& ss_mode
!= SS_ONSTACK
&&
3999 if (ss_mode
== SS_DISABLE
) {
4003 if (unlikely(ss_size
< min_ss_size
))
4007 t
->sas_ss_sp
= (unsigned long) ss_sp
;
4008 t
->sas_ss_size
= ss_size
;
4009 t
->sas_ss_flags
= ss_flags
;
4014 SYSCALL_DEFINE2(sigaltstack
,const stack_t __user
*,uss
, stack_t __user
*,uoss
)
4018 if (uss
&& copy_from_user(&new, uss
, sizeof(stack_t
)))
4020 err
= do_sigaltstack(uss
? &new : NULL
, uoss
? &old
: NULL
,
4021 current_user_stack_pointer(),
4023 if (!err
&& uoss
&& copy_to_user(uoss
, &old
, sizeof(stack_t
)))
4028 int restore_altstack(const stack_t __user
*uss
)
4031 if (copy_from_user(&new, uss
, sizeof(stack_t
)))
4033 (void)do_sigaltstack(&new, NULL
, current_user_stack_pointer(),
4035 /* squash all but EFAULT for now */
4039 int __save_altstack(stack_t __user
*uss
, unsigned long sp
)
4041 struct task_struct
*t
= current
;
4042 int err
= __put_user((void __user
*)t
->sas_ss_sp
, &uss
->ss_sp
) |
4043 __put_user(t
->sas_ss_flags
, &uss
->ss_flags
) |
4044 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
4047 if (t
->sas_ss_flags
& SS_AUTODISARM
)
4052 #ifdef CONFIG_COMPAT
4053 static int do_compat_sigaltstack(const compat_stack_t __user
*uss_ptr
,
4054 compat_stack_t __user
*uoss_ptr
)
4060 compat_stack_t uss32
;
4061 if (copy_from_user(&uss32
, uss_ptr
, sizeof(compat_stack_t
)))
4063 uss
.ss_sp
= compat_ptr(uss32
.ss_sp
);
4064 uss
.ss_flags
= uss32
.ss_flags
;
4065 uss
.ss_size
= uss32
.ss_size
;
4067 ret
= do_sigaltstack(uss_ptr
? &uss
: NULL
, &uoss
,
4068 compat_user_stack_pointer(),
4069 COMPAT_MINSIGSTKSZ
);
4070 if (ret
>= 0 && uoss_ptr
) {
4072 memset(&old
, 0, sizeof(old
));
4073 old
.ss_sp
= ptr_to_compat(uoss
.ss_sp
);
4074 old
.ss_flags
= uoss
.ss_flags
;
4075 old
.ss_size
= uoss
.ss_size
;
4076 if (copy_to_user(uoss_ptr
, &old
, sizeof(compat_stack_t
)))
4082 COMPAT_SYSCALL_DEFINE2(sigaltstack
,
4083 const compat_stack_t __user
*, uss_ptr
,
4084 compat_stack_t __user
*, uoss_ptr
)
4086 return do_compat_sigaltstack(uss_ptr
, uoss_ptr
);
4089 int compat_restore_altstack(const compat_stack_t __user
*uss
)
4091 int err
= do_compat_sigaltstack(uss
, NULL
);
4092 /* squash all but -EFAULT for now */
4093 return err
== -EFAULT
? err
: 0;
4096 int __compat_save_altstack(compat_stack_t __user
*uss
, unsigned long sp
)
4099 struct task_struct
*t
= current
;
4100 err
= __put_user(ptr_to_compat((void __user
*)t
->sas_ss_sp
),
4102 __put_user(t
->sas_ss_flags
, &uss
->ss_flags
) |
4103 __put_user(t
->sas_ss_size
, &uss
->ss_size
);
4106 if (t
->sas_ss_flags
& SS_AUTODISARM
)
4112 #ifdef __ARCH_WANT_SYS_SIGPENDING
4115 * sys_sigpending - examine pending signals
4116 * @uset: where mask of pending signal is returned
4118 SYSCALL_DEFINE1(sigpending
, old_sigset_t __user
*, uset
)
4122 if (sizeof(old_sigset_t
) > sizeof(*uset
))
4125 do_sigpending(&set
);
4127 if (copy_to_user(uset
, &set
, sizeof(old_sigset_t
)))
4133 #ifdef CONFIG_COMPAT
4134 COMPAT_SYSCALL_DEFINE1(sigpending
, compat_old_sigset_t __user
*, set32
)
4138 do_sigpending(&set
);
4140 return put_user(set
.sig
[0], set32
);
4146 #ifdef __ARCH_WANT_SYS_SIGPROCMASK
4148 * sys_sigprocmask - examine and change blocked signals
4149 * @how: whether to add, remove, or set signals
4150 * @nset: signals to add or remove (if non-null)
4151 * @oset: previous value of signal mask if non-null
4153 * Some platforms have their own version with special arguments;
4154 * others support only sys_rt_sigprocmask.
4157 SYSCALL_DEFINE3(sigprocmask
, int, how
, old_sigset_t __user
*, nset
,
4158 old_sigset_t __user
*, oset
)
4160 old_sigset_t old_set
, new_set
;
4161 sigset_t new_blocked
;
4163 old_set
= current
->blocked
.sig
[0];
4166 if (copy_from_user(&new_set
, nset
, sizeof(*nset
)))
4169 new_blocked
= current
->blocked
;
4173 sigaddsetmask(&new_blocked
, new_set
);
4176 sigdelsetmask(&new_blocked
, new_set
);
4179 new_blocked
.sig
[0] = new_set
;
4185 set_current_blocked(&new_blocked
);
4189 if (copy_to_user(oset
, &old_set
, sizeof(*oset
)))
4195 #endif /* __ARCH_WANT_SYS_SIGPROCMASK */
4197 #ifndef CONFIG_ODD_RT_SIGACTION
4199 * sys_rt_sigaction - alter an action taken by a process
4200 * @sig: signal to be sent
4201 * @act: new sigaction
4202 * @oact: used to save the previous sigaction
4203 * @sigsetsize: size of sigset_t type
4205 SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
4206 const struct sigaction __user
*, act
,
4207 struct sigaction __user
*, oact
,
4210 struct k_sigaction new_sa
, old_sa
;
4213 /* XXX: Don't preclude handling different sized sigset_t's. */
4214 if (sigsetsize
!= sizeof(sigset_t
))
4217 if (act
&& copy_from_user(&new_sa
.sa
, act
, sizeof(new_sa
.sa
)))
4220 ret
= do_sigaction(sig
, act
? &new_sa
: NULL
, oact
? &old_sa
: NULL
);
4224 if (oact
&& copy_to_user(oact
, &old_sa
.sa
, sizeof(old_sa
.sa
)))
4229 #ifdef CONFIG_COMPAT
4230 COMPAT_SYSCALL_DEFINE4(rt_sigaction
, int, sig
,
4231 const struct compat_sigaction __user
*, act
,
4232 struct compat_sigaction __user
*, oact
,
4233 compat_size_t
, sigsetsize
)
4235 struct k_sigaction new_ka
, old_ka
;
4236 #ifdef __ARCH_HAS_SA_RESTORER
4237 compat_uptr_t restorer
;
4241 /* XXX: Don't preclude handling different sized sigset_t's. */
4242 if (sigsetsize
!= sizeof(compat_sigset_t
))
4246 compat_uptr_t handler
;
4247 ret
= get_user(handler
, &act
->sa_handler
);
4248 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
4249 #ifdef __ARCH_HAS_SA_RESTORER
4250 ret
|= get_user(restorer
, &act
->sa_restorer
);
4251 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
4253 ret
|= get_compat_sigset(&new_ka
.sa
.sa_mask
, &act
->sa_mask
);
4254 ret
|= get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
);
4259 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
4261 ret
= put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
4263 ret
|= put_compat_sigset(&oact
->sa_mask
, &old_ka
.sa
.sa_mask
,
4264 sizeof(oact
->sa_mask
));
4265 ret
|= put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
);
4266 #ifdef __ARCH_HAS_SA_RESTORER
4267 ret
|= put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
4268 &oact
->sa_restorer
);
4274 #endif /* !CONFIG_ODD_RT_SIGACTION */
4276 #ifdef CONFIG_OLD_SIGACTION
4277 SYSCALL_DEFINE3(sigaction
, int, sig
,
4278 const struct old_sigaction __user
*, act
,
4279 struct old_sigaction __user
*, oact
)
4281 struct k_sigaction new_ka
, old_ka
;
4286 if (!access_ok(act
, sizeof(*act
)) ||
4287 __get_user(new_ka
.sa
.sa_handler
, &act
->sa_handler
) ||
4288 __get_user(new_ka
.sa
.sa_restorer
, &act
->sa_restorer
) ||
4289 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
4290 __get_user(mask
, &act
->sa_mask
))
4292 #ifdef __ARCH_HAS_KA_RESTORER
4293 new_ka
.ka_restorer
= NULL
;
4295 siginitset(&new_ka
.sa
.sa_mask
, mask
);
4298 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
4301 if (!access_ok(oact
, sizeof(*oact
)) ||
4302 __put_user(old_ka
.sa
.sa_handler
, &oact
->sa_handler
) ||
4303 __put_user(old_ka
.sa
.sa_restorer
, &oact
->sa_restorer
) ||
4304 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
4305 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
4312 #ifdef CONFIG_COMPAT_OLD_SIGACTION
4313 COMPAT_SYSCALL_DEFINE3(sigaction
, int, sig
,
4314 const struct compat_old_sigaction __user
*, act
,
4315 struct compat_old_sigaction __user
*, oact
)
4317 struct k_sigaction new_ka
, old_ka
;
4319 compat_old_sigset_t mask
;
4320 compat_uptr_t handler
, restorer
;
4323 if (!access_ok(act
, sizeof(*act
)) ||
4324 __get_user(handler
, &act
->sa_handler
) ||
4325 __get_user(restorer
, &act
->sa_restorer
) ||
4326 __get_user(new_ka
.sa
.sa_flags
, &act
->sa_flags
) ||
4327 __get_user(mask
, &act
->sa_mask
))
4330 #ifdef __ARCH_HAS_KA_RESTORER
4331 new_ka
.ka_restorer
= NULL
;
4333 new_ka
.sa
.sa_handler
= compat_ptr(handler
);
4334 new_ka
.sa
.sa_restorer
= compat_ptr(restorer
);
4335 siginitset(&new_ka
.sa
.sa_mask
, mask
);
4338 ret
= do_sigaction(sig
, act
? &new_ka
: NULL
, oact
? &old_ka
: NULL
);
4341 if (!access_ok(oact
, sizeof(*oact
)) ||
4342 __put_user(ptr_to_compat(old_ka
.sa
.sa_handler
),
4343 &oact
->sa_handler
) ||
4344 __put_user(ptr_to_compat(old_ka
.sa
.sa_restorer
),
4345 &oact
->sa_restorer
) ||
4346 __put_user(old_ka
.sa
.sa_flags
, &oact
->sa_flags
) ||
4347 __put_user(old_ka
.sa
.sa_mask
.sig
[0], &oact
->sa_mask
))
4354 #ifdef CONFIG_SGETMASK_SYSCALL
4357 * For backwards compatibility. Functionality superseded by sigprocmask.
4359 SYSCALL_DEFINE0(sgetmask
)
4362 return current
->blocked
.sig
[0];
4365 SYSCALL_DEFINE1(ssetmask
, int, newmask
)
4367 int old
= current
->blocked
.sig
[0];
4370 siginitset(&newset
, newmask
);
4371 set_current_blocked(&newset
);
4375 #endif /* CONFIG_SGETMASK_SYSCALL */
4377 #ifdef __ARCH_WANT_SYS_SIGNAL
4379 * For backwards compatibility. Functionality superseded by sigaction.
4381 SYSCALL_DEFINE2(signal
, int, sig
, __sighandler_t
, handler
)
4383 struct k_sigaction new_sa
, old_sa
;
4386 new_sa
.sa
.sa_handler
= handler
;
4387 new_sa
.sa
.sa_flags
= SA_ONESHOT
| SA_NOMASK
;
4388 sigemptyset(&new_sa
.sa
.sa_mask
);
4390 ret
= do_sigaction(sig
, &new_sa
, &old_sa
);
4392 return ret
? ret
: (unsigned long)old_sa
.sa
.sa_handler
;
4394 #endif /* __ARCH_WANT_SYS_SIGNAL */
4396 #ifdef __ARCH_WANT_SYS_PAUSE
4398 SYSCALL_DEFINE0(pause
)
4400 while (!signal_pending(current
)) {
4401 __set_current_state(TASK_INTERRUPTIBLE
);
4404 return -ERESTARTNOHAND
;
4409 static int sigsuspend(sigset_t
*set
)
4411 current
->saved_sigmask
= current
->blocked
;
4412 set_current_blocked(set
);
4414 while (!signal_pending(current
)) {
4415 __set_current_state(TASK_INTERRUPTIBLE
);
4418 set_restore_sigmask();
4419 return -ERESTARTNOHAND
;
4423 * sys_rt_sigsuspend - replace the signal mask for a value with the
4424 * @unewset value until a signal is received
4425 * @unewset: new signal mask value
4426 * @sigsetsize: size of sigset_t type
4428 SYSCALL_DEFINE2(rt_sigsuspend
, sigset_t __user
*, unewset
, size_t, sigsetsize
)
4432 /* XXX: Don't preclude handling different sized sigset_t's. */
4433 if (sigsetsize
!= sizeof(sigset_t
))
4436 if (copy_from_user(&newset
, unewset
, sizeof(newset
)))
4438 return sigsuspend(&newset
);
4441 #ifdef CONFIG_COMPAT
4442 COMPAT_SYSCALL_DEFINE2(rt_sigsuspend
, compat_sigset_t __user
*, unewset
, compat_size_t
, sigsetsize
)
4446 /* XXX: Don't preclude handling different sized sigset_t's. */
4447 if (sigsetsize
!= sizeof(sigset_t
))
4450 if (get_compat_sigset(&newset
, unewset
))
4452 return sigsuspend(&newset
);
4456 #ifdef CONFIG_OLD_SIGSUSPEND
4457 SYSCALL_DEFINE1(sigsuspend
, old_sigset_t
, mask
)
4460 siginitset(&blocked
, mask
);
4461 return sigsuspend(&blocked
);
4464 #ifdef CONFIG_OLD_SIGSUSPEND3
4465 SYSCALL_DEFINE3(sigsuspend
, int, unused1
, int, unused2
, old_sigset_t
, mask
)
4468 siginitset(&blocked
, mask
);
4469 return sigsuspend(&blocked
);
4473 __weak
const char *arch_vma_name(struct vm_area_struct
*vma
)
4478 static inline void siginfo_buildtime_checks(void)
4480 BUILD_BUG_ON(sizeof(struct siginfo
) != SI_MAX_SIZE
);
4482 /* Verify the offsets in the two siginfos match */
4483 #define CHECK_OFFSET(field) \
4484 BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
4487 CHECK_OFFSET(si_pid
);
4488 CHECK_OFFSET(si_uid
);
4491 CHECK_OFFSET(si_tid
);
4492 CHECK_OFFSET(si_overrun
);
4493 CHECK_OFFSET(si_value
);
4496 CHECK_OFFSET(si_pid
);
4497 CHECK_OFFSET(si_uid
);
4498 CHECK_OFFSET(si_value
);
4501 CHECK_OFFSET(si_pid
);
4502 CHECK_OFFSET(si_uid
);
4503 CHECK_OFFSET(si_status
);
4504 CHECK_OFFSET(si_utime
);
4505 CHECK_OFFSET(si_stime
);
4508 CHECK_OFFSET(si_addr
);
4509 CHECK_OFFSET(si_addr_lsb
);
4510 CHECK_OFFSET(si_lower
);
4511 CHECK_OFFSET(si_upper
);
4512 CHECK_OFFSET(si_pkey
);
4515 CHECK_OFFSET(si_band
);
4516 CHECK_OFFSET(si_fd
);
4519 CHECK_OFFSET(si_call_addr
);
4520 CHECK_OFFSET(si_syscall
);
4521 CHECK_OFFSET(si_arch
);
4525 BUILD_BUG_ON(offsetof(struct siginfo
, si_pid
) !=
4526 offsetof(struct siginfo
, si_addr
));
4527 if (sizeof(int) == sizeof(void __user
*)) {
4528 BUILD_BUG_ON(sizeof_field(struct siginfo
, si_pid
) !=
4529 sizeof(void __user
*));
4531 BUILD_BUG_ON((sizeof_field(struct siginfo
, si_pid
) +
4532 sizeof_field(struct siginfo
, si_uid
)) !=
4533 sizeof(void __user
*));
4534 BUILD_BUG_ON(offsetofend(struct siginfo
, si_pid
) !=
4535 offsetof(struct siginfo
, si_uid
));
4537 #ifdef CONFIG_COMPAT
4538 BUILD_BUG_ON(offsetof(struct compat_siginfo
, si_pid
) !=
4539 offsetof(struct compat_siginfo
, si_addr
));
4540 BUILD_BUG_ON(sizeof_field(struct compat_siginfo
, si_pid
) !=
4541 sizeof(compat_uptr_t
));
4542 BUILD_BUG_ON(sizeof_field(struct compat_siginfo
, si_pid
) !=
4543 sizeof_field(struct siginfo
, si_pid
));
4547 void __init
signals_init(void)
4549 siginfo_buildtime_checks();
4551 sigqueue_cachep
= KMEM_CACHE(sigqueue
, SLAB_PANIC
);
4554 #ifdef CONFIG_KGDB_KDB
4555 #include <linux/kdb.h>
4557 * kdb_send_sig - Allows kdb to send signals without exposing
4558 * signal internals. This function checks if the required locks are
4559 * available before calling the main signal code, to avoid kdb
4562 void kdb_send_sig(struct task_struct
*t
, int sig
)
4564 static struct task_struct
*kdb_prev_t
;
4566 if (!spin_trylock(&t
->sighand
->siglock
)) {
4567 kdb_printf("Can't do kill command now.\n"
4568 "The sigmask lock is held somewhere else in "
4569 "kernel, try again later\n");
4572 new_t
= kdb_prev_t
!= t
;
4574 if (t
->state
!= TASK_RUNNING
&& new_t
) {
4575 spin_unlock(&t
->sighand
->siglock
);
4576 kdb_printf("Process is not RUNNING, sending a signal from "
4577 "kdb risks deadlock\n"
4578 "on the run queue locks. "
4579 "The signal has _not_ been sent.\n"
4580 "Reissue the kill command if you want to risk "
4584 ret
= send_signal(sig
, SEND_SIG_PRIV
, t
, PIDTYPE_PID
);
4585 spin_unlock(&t
->sighand
->siglock
);
4587 kdb_printf("Fail to deliver Signal %d to process %d.\n",
4590 kdb_printf("Signal %d is sent to process %d.\n", sig
, t
->pid
);
4592 #endif /* CONFIG_KGDB_KDB */