--- a/net/server_epoll.lua	Sun Oct 14 14:32:02 2018 +0200
+++ b/net/server_epoll.lua	Fri Oct 12 03:20:09 2018 +0200
@@ -25,7 +25,10 @@
 local inet_pton = inet.pton;
 local _SOCKETINVALID = socket._SOCKETINVALID or -1;
 
-local poll = assert(require "util.poll".new());
+local poller = require "util.poll"
+local EEXIST = poller.EEXIST;
+
+local poll = assert(poller.new());
 
 local _ENV = nil;
 -- luacheck: std none
@@ -269,6 +272,10 @@
 	if w == nil then w = self._wantwrite; end
 	local ok, err, errno = poll:add(fd, r, w);
 	if not ok then
+		if errno == EEXIST then
+			log("debug", "%s already registered!", self);
+			return self:set(r, w); -- So try to change its flags
+		end
 		log("error", "Could not register %s: %s(%d)", self, err, errno);
 		return ok, err;
 	end

--- a/util-src/poll.c	Sun Oct 14 14:32:02 2018 +0200
+++ b/util-src/poll.c	Fri Oct 12 03:20:09 2018 +0200
@@ -452,10 +452,16 @@
 #endif
 	}
 
-	lua_createtable(L, 0, 1);
+	lua_createtable(L, 0, 2);
 	{
 		lua_pushcfunction(L, Lnew);
 		lua_setfield(L, -2, "new");
+
+#define push_errno(named_error) lua_pushinteger(L, named_error);\
+		lua_setfield(L, -2, #named_error);
+
+		push_errno(EEXIST);
+
 	}
 	return 1;
 }