Index: sys/kern/subr_taskqueue.c
===================================================================
--- sys/kern/subr_taskqueue.c
+++ sys/kern/subr_taskqueue.c
@@ -558,9 +558,33 @@
 taskqueue_drain_timeout(struct taskqueue *queue,
     struct timeout_task *timeout_task)
 {
+	u_int pending;
 
-	callout_drain(&timeout_task->c);
-	taskqueue_drain(queue, &timeout_task->t);
+	if (!queue->tq_spin)
+		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
+
+	do {
+		pending = 0;
+
+		callout_drain(&timeout_task->c);
+
+		TQ_LOCK(queue);
+		while (timeout_task->t.ta_pending != 0 ||
+		    task_is_running(queue, &timeout_task->t)) {
+			TQ_SLEEP(queue, &timeout_task->t, &queue->tq_mutex,
+			    PWAIT, "-", 0);
+			pending = 1;
+		}
+		TQ_UNLOCK(queue);
+
+		/*
+		 * In case the taskqueue was pending we need to loop
+		 * in order to fully drain, because the task we are
+		 * draining might invoke the task again and restart
+		 * the callout.
+		 */
+		
+	} while (pending != 0);
 }
 
 static void