BUG/MINOR: signals/poller: ensure wakeup from signals
Add self-wake in signal_handler() to fix a race condition with a signal
coming in between checking signal_queue_len and entering polling sleep.
The changes in commit 43c891dda ("BUG/MINOR: signals/poller: set the
poller timeout to 0 when there are signals") were insufficient.
Move the signal_queue_len check from the poll implementations to
run_poll_loop() to keep that logic in one place.
The poll loops are terminated either by the parameter wake being set or
wake up due to a write to their poller_wr_pipe by wake_thread() in
signal_handler().
This fixes issue #1841.
Must be backported in every stable version.
(cherry picked from commit eea152ee68e82eae49ae188cd1b1fbbf63dc6913)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 4a1f703e9ac18c98248e4e157a000cd270989cc2)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 3fbe970d9ab4ed211687101fb61ca49d809a2f58)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/ev_poll.c b/src/ev_poll.c
index da675eb..4d136a0 100644
--- a/src/ev_poll.c
+++ b/src/ev_poll.c
@@ -199,10 +199,8 @@
}
}
- /* Now let's wait for polled events.
- * Check if the signal queue is not empty in case we received a signal
- * before entering the loop, so we don't wait MAX_DELAY_MS for nothing */
- wait_time = (wake | signal_queue_len) ? 0 : compute_poll_timeout(exp);
+ /* Now let's wait for polled events. */
+ wait_time = wake ? 0 : compute_poll_timeout(exp);
tv_entering_poll();
activity_count_runtime();
status = poll(poll_events, nbfd, wait_time);