diff --git a/kernel/tasks.c b/kernel/tasks.c
index 743a0a9e..bc037aad 100644
--- a/kernel/tasks.c
+++ b/kernel/tasks.c
@@ -1017,8 +1017,9 @@ int set_timer(uint64_t deadline)
 				if (runqueues[core_id].timers.last)
 					runqueues[core_id].timers.last->next = curr_task;
 				runqueues[core_id].timers.last = curr_task;
-				if (!runqueues[core_id].timers.first)
-					runqueues[core_id].timers.first = curr_task;
+				// obsolete lines...
+				//if (!runqueues[core_id].timers.first)
+				//	runqueues[core_id].timers.first = curr_task;
 			} else {
 				curr_task->prev = tmp->prev;
 				curr_task->next = tmp;
@@ -1198,7 +1199,9 @@ void scheduler(void)
 
 		// remove timer from queue
 		runqueues[core_id].timers.first = runqueues[core_id].timers.first->next;
-		if (!runqueues[core_id].timers.first)
+		if (runqueues[core_id].timers.first)
+			runqueues[core_id].timers.first->prev = NULL;
+		else
 			runqueues[core_id].timers.last = NULL;
 		task->flags &= ~TASK_TIMER;