diff --git a/lualib/skynet.lua b/lualib/skynet.lua
index 908701878..0e938e18d 100644
--- a/lualib/skynet.lua
+++ b/lualib/skynet.lua
@@ -126,10 +126,11 @@ local function co_create(f)
 end
 
 local function dispatch_wakeup()
-	local co = table.remove(wakeup_queue,1)
-	if co then
-		local session = sleep_session[co]
+	local token = table.remove(wakeup_queue,1)
+	if token then
+		local session = sleep_session[token]
 		if session then
+			local co = session_id_coroutine[session]
 			session_id_coroutine[session] = "BREAK"
 			return suspend(co, coroutine_resume(co, false, "BREAK"))
 		end
@@ -149,7 +150,7 @@ local function release_watching(address)
 end
 
 -- suspend is local function
-function suspend(co, result, command, param, size)
+function suspend(co, result, command, param, param2)
 	if not result then
 		local session = session_coroutine_id[co]
 		if session then -- coroutine may fork by others (session is nil)
@@ -167,13 +168,16 @@ function suspend(co, result, command, param, size)
 		session_id_coroutine[param] = co
 	elseif command == "SLEEP" then
 		session_id_coroutine[param] = co
-		sleep_session[co] = param
+		if sleep_session[param2] then
+			error(debug.traceback(co, "token duplicative"))
+		end
+		sleep_session[param2] = param
 	elseif command == "RETURN" then
 		local co_session = session_coroutine_id[co]
 		session_coroutine_id[co] = nil
 		if co_session == 0 then
-			if size ~= nil then
-				c.trash(param, size)
+			if param2 ~= nil then
+				c.trash(param, param2)
 			end
 			return suspend(co, coroutine_resume(co, false))	-- send don't need ret
 		end
@@ -183,13 +187,13 @@ function suspend(co, result, command, param, size)
 		end
 		local ret
 		if not dead_service[co_address] then
-			ret = c.send(co_address, skynet.PTYPE_RESPONSE, co_session, param, size) ~= nil
+			ret = c.send(co_address, skynet.PTYPE_RESPONSE, co_session, param, param2) ~= nil
 			if not ret then
 				-- If the package is too large, returns nil. so we should report error back
 				c.send(co_address, skynet.PTYPE_ERROR, co_session, "")
 			end
-		elseif size ~= nil then
-			c.trash(param, size)
+		elseif param2 ~= nil then
+			c.trash(param, param2)
 			ret = false
 		end
 		return suspend(co, coroutine_resume(co, ret))
@@ -279,11 +283,12 @@ function skynet.timeout(ti, func)
 	session_id_coroutine[session] = co
 end
 
-function skynet.sleep(ti)
+function skynet.sleep(ti, token)
 	local session = c.intcommand("TIMEOUT",ti)
 	assert(session)
-	local succ, ret = coroutine_yield("SLEEP", session)
-	sleep_session[coroutine.running()] = nil
+	token = token or coroutine.running()
+	local succ, ret = coroutine_yield("SLEEP", session, token)
+	sleep_session[token] = nil
 	if succ then
 		return
 	end
@@ -298,11 +303,11 @@ function skynet.yield()
 	return skynet.sleep(0)
 end
 
-function skynet.wait(co)
+function skynet.wait(token)
 	local session = c.genid()
-	local ret, msg = coroutine_yield("SLEEP", session)
-	co = co or coroutine.running()
-	sleep_session[co] = nil
+	token = token or coroutine.running()
+	local ret, msg = coroutine_yield("SLEEP", session, token)
+	sleep_session[token] = nil
 	session_id_coroutine[session] = nil
 end
 
@@ -429,9 +434,9 @@ function skynet.retpack(...)
 	return skynet.ret(skynet.pack(...))
 end
 
-function skynet.wakeup(co)
-	if sleep_session[co] then
-		table.insert(wakeup_queue, co)
+function skynet.wakeup(token)
+	if sleep_session[token] then
+		table.insert(wakeup_queue, token)
 		return true
 	end
 end
diff --git a/test/testtimeout.lua b/test/testtimeout.lua
index 94355ab23..88c3deff2 100644
--- a/test/testtimeout.lua
+++ b/test/testtimeout.lua
@@ -14,18 +14,15 @@ local function test_service()
 end
 
 local function timeout_call(ti, ...)
-	local co = coroutine.running()
+	local token = {}
 	local ret
 
 	skynet.fork(function(...)
 		ret = table.pack(pcall(skynet.call, ...))
-		if co then
-			skynet.wakeup(co)
-		end
+		skynet.wakeup(token)
 	end, ...)
 
-	skynet.sleep(ti)
-	co = nil	-- prevent wakeup after call
+	skynet.sleep(ti, token)
 	if ret then
 		if ret[1] then
 			return table.unpack(ret, 1, ret.n)
@@ -45,6 +42,8 @@ skynet.start(function()
 	skynet.error("2", skynet.now())
 	skynet.error(timeout_call(50, test, "lua"))
 	skynet.error("3", skynet.now())
+	skynet.error(timeout_call(150, test, "lua"))
+	skynet.error("4", skynet.now())
 	skynet.exit()
 end)