diff --git a/skynet-src/skynet_socket.c b/skynet-src/skynet_socket.c
index 5e1b8111..c4c509d4 100644
--- a/skynet-src/skynet_socket.c
+++ b/skynet-src/skynet_socket.c
@@ -37,6 +37,7 @@ forward_message(int type, bool padding, struct socket_message * result) {
 		if (result->data) {
 			sz += strlen(result->data) + 1;
 		} else {
+			result->data = "";
 			sz += 1;
 		}
 	}