diff --git a/lualib/skynet.lua b/lualib/skynet.lua
index 5b5762c3..19d28b56 100644
--- a/lualib/skynet.lua
+++ b/lualib/skynet.lua
@@ -992,19 +992,19 @@ function skynet.newservice(name, ...)
 	return skynet.call(".launcher", "lua" , "LAUNCH", "snlua", name, ...)
 end
 
-function skynet.uniqueservice(global, ...)
-	if global == true then
+function skynet.uniqueservice(name, ...)
+	if name == true then
 		return assert(skynet.call(".service", "lua", "GLAUNCH", ...))
 	else
-		return assert(skynet.call(".service", "lua", "LAUNCH", global, ...))
+		return assert(skynet.call(".service", "lua", "LAUNCH", name, ...))
 	end
 end
 
-function skynet.queryservice(global, ...)
-	if global == true then
+function skynet.queryservice(name, ...)
+	if name == true then
 		return assert(skynet.call(".service", "lua", "GQUERY", ...))
 	else
-		return assert(skynet.call(".service", "lua", "QUERY", global, ...))
+		return assert(skynet.call(".service", "lua", "QUERY", name, ...))
 	end
 end
 
diff --git a/lualib/skynet/db/redis.lua b/lualib/skynet/db/redis.lua
index 8aad0856..36e199e1 100644
--- a/lualib/skynet/db/redis.lua
+++ b/lualib/skynet/db/redis.lua
@@ -213,10 +213,11 @@ end
 local function compose_table(lines, msg)
 	local tinsert = table.insert
 	tinsert(lines, count_cache[#msg])
+	local val
 	for _,v in ipairs(msg) do
-		v = tostring(v)
-		tinsert(lines,header_cache[#v])
-		tinsert(lines,v)
+		val = tostring(v)
+		tinsert(lines,header_cache[#val])
+		tinsert(lines,val)
 	end
 	tinsert(lines, "\r\n")
 	return lines
diff --git a/lualib/skynet/dns.lua b/lualib/skynet/dns.lua
index 3e112964..403b43cb 100644
--- a/lualib/skynet/dns.lua
+++ b/lualib/skynet/dns.lua
@@ -130,11 +130,11 @@ local function parse_hosts()
 		end
 
 		for host in hosts:gmatch("%S+") do
-			host = host:lower()
-			local rt = rts[host]
+			local h = host:lower()
+			local rt = rts[h]
 			if not rt then
 				rt = {}
-				rts[host] = rt
+				rts[h] = rt
 			end
 
 			if not rt[family] then
diff --git a/lualib/snax/hotfix.lua b/lualib/snax/hotfix.lua
index 910fbda3..e31bcb16 100644
--- a/lualib/snax/hotfix.lua
+++ b/lualib/snax/hotfix.lua
@@ -40,16 +40,16 @@ local function collect_uv(f , uv, env)
 end
 
 local function collect_all_uv(funcs)
-	local global = {}
+	local globals = {}
 	for _, v in pairs(funcs) do
 		if v[4] then
-			collect_uv(v[4], global, envid(v[4]))
+			collect_uv(v[4], globals, envid(v[4]))
 		end
 	end
-	if not global["_ENV"] then
-		global["_ENV"] = {func = collect_uv, index = 1}
+	if not globals["_ENV"] then
+		globals["_ENV"] = {func = collect_uv, index = 1}
 	end
-	return global
+	return globals
 end
 
 local function loader(source)
@@ -70,40 +70,40 @@ end
 local dummy_env = {}
 for k,v in pairs(_ENV) do dummy_env[k] = v end
 
-local function _patch(global, f)
+local function _patch(globals, f)
 	local i = 1
 	while true do
 		local name, value = debug.getupvalue(f, i)
 		if name == nil then
 			break
 		elseif value == nil or value == dummy_env then
-			local old_uv = global[name]
+			local old_uv = globals[name]
 			if old_uv then
 				debug.upvaluejoin(f, i, old_uv.func, old_uv.index)
 			end
 		else
 			if type(value) == "function" then
-				_patch(global, value)
+				_patch(globals, value)
 			end
 		end
 		i = i + 1
 	end
 end
 
-local function patch_func(funcs, global, group, name, f)
+local function patch_func(funcs, globals, group, name, f)
 	local desc = assert(find_func(funcs, group, name) , string.format("Patch mismatch %s.%s", group, name))
-	_patch(global, f)
+	_patch(globals, f)
 	desc[4] = f
 end
 
 local function inject(funcs, source, ...)
 	local patch = si("patch", dummy_env, loader(source))
-	local global = collect_all_uv(funcs)
+	local globals = collect_all_uv(funcs)
 
 	for _, v in pairs(patch) do
 		local _, group, name, f = table.unpack(v)
 		if f then
-			patch_func(funcs, global, group, name, f)
+			patch_func(funcs, globals, group, name, f)
 		end
 	end
 
diff --git a/service/clusterd.lua b/service/clusterd.lua
index 82b19f5c..ae410601 100644
--- a/service/clusterd.lua
+++ b/service/clusterd.lua
@@ -102,9 +102,9 @@ local function loadconfig(tmp)
 	local reload = {}
 	for name,address in pairs(tmp) do
 		if name:sub(1,2) == "__" then
-			name = name:sub(3)
-			config[name] = address
-			skynet.error(string.format("Config %s = %s", name, address))
+			local opt = name:sub(3)
+			config[opt] = address
+			skynet.error(string.format("Config %s = %s", opt, address))
 		else
 			assert(address == false or type(address) == "string")
 			if node_address[name] ~= address then
diff --git a/service/service_mgr.lua b/service/service_mgr.lua
index 09345955..71280f0a 100644
--- a/service/service_mgr.lua
+++ b/service/service_mgr.lua
@@ -96,10 +96,11 @@ function cmd.QUERY(service_name, subname)
 end
 
 local function list_service()
+	local val
 	local result = {}
 	for k,v in pairs(service) do
 		if type(v) == "string" then
-			v = "Error: " .. v
+			val = "Error: " .. v
 		elseif type(v) == "table" then
 			local querying = {}
 			if v.launch then
@@ -118,12 +119,12 @@ local function list_service()
 					table.insert(querying, skynet.address(detail.source) .. " " .. tostring(skynet.call(detail.source, "debug", "TASK", detail.session)))
 				end
 			end
-			v = table.concat(querying, "\n")
+			val = table.concat(querying, "\n")
 		else
-			v = skynet.address(v)
+			val = skynet.address(v)
 		end
 
-		result[k] = v
+		result[k] = val
 	end
 
 	return result