--- a/net/server_epoll.lua	Wed Jan 04 13:18:06 2017 +0100
+++ b/net/server_epoll.lua	Thu Jan 05 06:21:31 2017 +0100
@@ -472,7 +472,7 @@
 		server = server;
 		created = gettime();
 		listeners = listeners;
-		_pattern = pattern or server._pattern;
+		_pattern = pattern or (server and server._pattern);
 		writebuffer = {};
 		tls = tls;
 	}, interface_mt);