Queue posixtimers which have their signal ignored on the ignored list:
1) When the timer fires and the signal has SIG_IGN set
2) When SIG_IGN is installed via sigaction() and a timer signal
is queued
This completes the SIG_IGN handling and such timers are not longer self
rearmed which avoids pointless wakeups.
Signed-off-by: Thomas Gleixner <[email protected]>
---
kernel/signal.c | 44 ++++++++++++++++++++++++++++++++++++--------
1 file changed, 36 insertions(+), 8 deletions(-)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -722,6 +722,16 @@ void signal_wake_up_state(struct task_st
kick_process(t);
}
+static inline void posixtimer_sig_ignore(struct task_struct *tsk, struct sigqueue *q);
+
+static void sigqueue_free_ignored(struct task_struct *ptmr_tsk, struct sigqueue *q)
+{
+ if (likely(!ptmr_tsk || q->info.si_code != SI_TIMER))
+ __sigqueue_free(q);
+ else
+ posixtimer_sig_ignore(ptmr_tsk, q);
+}
+
/*
* Remove signals in mask from the pending set and queue.
*
@@ -740,7 +750,7 @@ static void flush_sigqueue_mask(sigset_t
list_for_each_entry_safe(q, n, &s->list, list) {
if (sigismember(mask, q->info.si_signo)) {
list_del_init(&q->list);
- __sigqueue_free(q);
+ sigqueue_free_ignored(ptmr_tsk, q);
}
}
}
@@ -1964,9 +1974,8 @@ int posixtimer_send_sigqueue(struct k_it
int sig = q->info.si_signo;
struct task_struct *t;
unsigned long flags;
- int ret, result;
+ int result;
- ret = -1;
rcu_read_lock();
t = posixtimer_get_target(tmr);
@@ -2012,13 +2021,24 @@ int posixtimer_send_sigqueue(struct k_it
*/
q->info.si_overrun = 0;
- ret = 1; /* the signal is ignored */
if (!prepare_signal(sig, t, false)) {
result = TRACE_SIGNAL_IGNORED;
+
+ /* Paranoia check. Try to survive. */
+ if (WARN_ON_ONCE(!list_empty(&q->list)))
+ goto out;
+
+ if (hlist_unhashed(&tmr->ignored_list)) {
+ hlist_add_head(&tmr->ignored_list, &t->signal->ignored_posix_timers);
+ posixtimer_sigqueue_getref(q);
+ }
goto out;
}
- ret = 0;
+ /* This should never happen and leaks a reference count */
+ if (WARN_ON_ONCE(!hlist_unhashed(&tmr->ignored_list)))
+ hlist_del_init(&tmr->ignored_list);
+
if (unlikely(!list_empty(&q->list))) {
/* This holds a reference count already */
result = TRACE_SIGNAL_ALREADY_PENDING;
@@ -2033,7 +2053,14 @@ int posixtimer_send_sigqueue(struct k_it
unlock_task_sighand(t, &flags);
ret:
rcu_read_unlock();
- return ret;
+ return 0;
+}
+
+static inline void posixtimer_sig_ignore(struct task_struct *tsk, struct sigqueue *q)
+{
+ struct k_itimer *tmr = container_of(q, struct k_itimer, sigq);
+
+ hlist_add_head(&tmr->ignored_list, &tsk->signal->ignored_posix_timers);
}
static void posixtimer_sig_unignore(struct task_struct *tsk, int sig)
@@ -2082,6 +2109,7 @@ static void posixtimer_sig_unignore(stru
}
}
#else /* CONFIG_POSIX_TIMERS */
+static inline void posixtimer_sig_ignore(struct task_struct *tsk, struct sigqueue *q) { }
static inline void posixtimer_sig_unignore(struct task_struct *tsk, int sig) { }
#endif /* !CONFIG_POSIX_TIMERS */
@@ -4272,9 +4300,9 @@ int do_sigaction(int sig, struct k_sigac
if (sig_handler_ignored(sig_handler(p, sig), sig)) {
sigemptyset(&mask);
sigaddset(&mask, sig);
- flush_sigqueue_mask(&mask, &p->signal->shared_pending, NULL);
+ flush_sigqueue_mask(&mask, &p->signal->shared_pending, p);
for_each_thread(p, t)
- flush_sigqueue_mask(&mask, &t->pending, NULL);
+ flush_sigqueue_mask(&mask, &t->pending, p);
} else if (was_ignored) {
posixtimer_sig_unignore(p, sig);
}