diff --git a/skynet-src/skynet_start.c b/skynet-src/skynet_start.c
index 258e41b4..b2991034 100644
--- a/skynet-src/skynet_start.c
+++ b/skynet-src/skynet_start.c
@@ -33,7 +33,7 @@ struct worker_parm {
 	int weight;
 };
 
-static int SIG = 0;
+static volatile int SIG = 0;
 
 static void
 handle_hup(int signal) {