diff --git a/lualib/cluster.lua b/lualib/cluster.lua
index dba8f318..9883227f 100644
--- a/lualib/cluster.lua
+++ b/lualib/cluster.lua
@@ -8,6 +8,11 @@ function cluster.call(node, address, ...)
 	return skynet.call(clusterd, "lua", "req", node, address, skynet.pack(...))
 end
 
+function cluster.send(node, address, ...)
+	-- skynet.pack(...) will free by cluster.core.packrequest
+	skynet.send(clusterd, "lua", "req", node, address, skynet.pack(...))
+end
+
 function cluster.open(port)
 	if type(port) == "string" then
 		skynet.call(clusterd, "lua", "listen", port)
diff --git a/lualib/skynet.lua b/lualib/skynet.lua
index 9a590d1d..c3b98942 100644
--- a/lualib/skynet.lua
+++ b/lualib/skynet.lua
@@ -161,6 +161,9 @@ function suspend(co, result, command, param, size)
 		sleep_session[co] = param
 	elseif command == "RETURN" then
 		local co_session = session_coroutine_id[co]
+		if co_session == 0 then
+			return suspend(co, coroutine_resume(co, false))	-- send don't need ret
+		end
 		local co_address = session_coroutine_address[co]
 		if param == nil or session_response[co] then
 			error(debug.traceback(co))