Use poller threads to handle canceled timer. (#1679)

src/kernel/poller.c

@@ -1600,6 +1600,7 @@ int poller_add_timer(const struct timespec *value, void *context, void **timer,
 int poller_del_timer(void *timer, poller_t *poller)
 {
 	struct __poller_node *node = (struct __poller_node *)timer;
+	int stopped = 0;
 
 	pthread_mutex_lock(&poller->mutex);
 	if (!node->removed)
@@ -1610,6 +1611,12 @@ int poller_del_timer(void *timer, poller_t *poller)
 			__poller_tree_erase(node, poller);
 		else
 			list_del(&node->list);
+
+		node->error = 0;
+		node->state = PR_ST_DELETED;
+		stopped = poller->stopped;
+		if (!stopped)
+			write(poller->pipe_wr, &node, sizeof (void *));
 	}
 	else
 	{
@@ -1618,15 +1625,10 @@ int poller_del_timer(void *timer, poller_t *poller)
 	}
 
 	pthread_mutex_unlock(&poller->mutex);
-	if (node)
-	{
-		node->error = 0;
-		node->state = PR_ST_DELETED;
+	if (stopped)
 		poller->callback((struct poller_result *)node, poller->context);
-		return 0;
-	}
 
-	return -1;
+	return -!node;
 }
 
 void poller_stop(poller_t *poller)