diff --git a/lualib/skynet/debug.lua b/lualib/skynet/debug.lua
index 79c51ad1..6e886f02 100644
--- a/lualib/skynet/debug.lua
+++ b/lualib/skynet/debug.lua
@@ -1,4 +1,5 @@
 local table = table
+local extern_dbgcmd = {};
 
 return function (skynet, export)
 
@@ -11,7 +12,7 @@ end
 local dbgcmd
 
 local function init_dbgcmd()
-dbgcmd = {}
+dbgcmd = extern_dbgcmd
 
 function dbgcmd.MEM()
 	local kb, bytes = collectgarbage "count"