diff --git a/src/signal.c b/src/signal.c
index b33e24220e..d4a4e2ef4d 100644
--- a/src/signal.c
+++ b/src/signal.c
@@ -499,6 +499,7 @@ void rt_thread_handle_sig(rt_bool_t clean_state)
             }
             else
             {
+                rt_spin_unlock_irqrestore(&_thread_signal_lock, level);
                 return;
             }
         }