diff --git a/src/clock.c b/src/clock.c
index 0880d8d24189b242b2a8cf405ef6c6f2b97ce00b..07dc1bce58f7396a36a235d5f54d234ca8dc5fc3 100644
--- a/src/clock.c
+++ b/src/clock.c
@@ -72,6 +72,11 @@ void rt_tick_increase(void)
 
     /* check time slice */
     thread = rt_thread_self();
+    if (thread == RT_NULL)
+    {
+        rt_hw_interrupt_enable(level);
+        return;
+    }
 
     -- thread->remaining_tick;
     if (thread->remaining_tick == 0)