diff --git a/skynet-src/socket_server.c b/skynet-src/socket_server.c
index 630f86eb..c24b0745 100644
--- a/skynet-src/socket_server.c
+++ b/skynet-src/socket_server.c
@@ -1205,7 +1205,17 @@ socket_server_poll(struct socket_server *ss, struct socket_message * result, int
 			break;
 		default:
 			if (e->read) {
-				int type = (s->protocol == PROTOCOL_TCP ? forward_message_tcp : forward_message_udp)(ss, s, result);
+				int type;
+				if (s->protocol == PROTOCOL_TCP) {
+					type = forward_message_tcp(ss, s, result);
+				} else {
+					type = forward_message_udp(ss, s, result);
+					if (type == SOCKET_UDP) {
+						// try read again
+						--ss->event_index;
+						return SOCKET_UDP;
+					}
+				}
 				if (e->write) {
 					// Try to dispatch write message next step if write flag set.
 					e->read = false;
@@ -1452,6 +1462,8 @@ socket_server_udp(struct socket_server *ss, uintptr_t opaque, const char * addr,
 			return -1;
 		}
 	}
+	sp_nonblocking(fd);
+
 	int id = reserve_id(ss);
 	if (id < 0) {
 		close(fd);
diff --git a/test/testudp.lua b/test/testudp.lua
index 63ca8d7a..d8387e29 100644
--- a/test/testudp.lua
+++ b/test/testudp.lua
@@ -4,8 +4,9 @@ local socket = require "socket"
 local function server()
 	local host
 	host = socket.udp(function(data, sz, from)
-		print("server recv", skynet.tostring(data,sz), socket.udp_address(from))
-		socket.sendto(host, from, "OK")
+		local str = skynet.tostring(data,sz)	-- skynet.tostring should call only once, because it will free the pointer data
+		print("server recv", str, socket.udp_address(from))
+		socket.sendto(host, from, "OK " .. str)
 	end , "127.0.0.1", 8765)	-- bind an address
 end
 
@@ -14,7 +15,9 @@ local function client()
 		print("client recv", skynet.tostring(data,sz), socket.udp_address(from))
 	end)
 	socket.udp_connect(c, "127.0.0.1", 8765)
-	socket.write(c, "hello")	-- write to the address by udp_connect binding
+	for i=1,20 do
+		socket.write(c, "hello " .. i)	-- write to the address by udp_connect binding
+	end
 end
 
 skynet.start(function()