diff --git a/src/task.c b/src/task.c
index c91316cbb..cabfcbe1e 100644
--- a/src/task.c
+++ b/src/task.c
@@ -346,7 +346,7 @@ int next_timer_expiry()
 	struct task_per_thread * const tt = sched; // thread's tasks
 	struct eb32_node *eb;
 	int ret = TICK_ETERNITY;
-	__decl_thread(int key);
+	__decl_thread(int key = TICK_ETERNITY);
 
 	/* first check in the thread-local timers */
 	eb = eb32_lookup_ge(&tt->timers, now_ms - TIMER_LOOK_BACK);