From 14771cdaeea6085bc134f3d8e231c55afa977819 Mon Sep 17 00:00:00 2001
From: Feng Lee <feng@emqtt.io>
Date: Mon, 20 Nov 2017 10:10:32 +0800
Subject: [PATCH] Fix issue #1340 - erlang:demonitor/1 the reference when
 erasing the monitor

---
 src/emqttd_cm.erl | 1 +
 src/emqttd_sm.erl | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/emqttd_cm.erl b/src/emqttd_cm.erl
index c5f0ff145..4edc155df 100644
--- a/src/emqttd_cm.erl
+++ b/src/emqttd_cm.erl
@@ -152,6 +152,7 @@ monitor_client(ClientId, Pid, State = #state{monitors = Monitors}) ->
     State#state{monitors = dict:store(MRef, {ClientId, Pid}, Monitors)}.
 
 erase_monitor(MRef, State = #state{monitors = Monitors}) ->
+    erlang:demonitor(MRef, [flush]),
     State#state{monitors = dict:erase(MRef, Monitors)}.
 
 setstats(State = #state{statsfun = StatsFun}) ->
diff --git a/src/emqttd_sm.erl b/src/emqttd_sm.erl
index 8d4c220b2..054e81c95 100644
--- a/src/emqttd_sm.erl
+++ b/src/emqttd_sm.erl
@@ -310,5 +310,6 @@ monitor_session(ClientId, SessPid, State = #state{monitors = Monitors}) ->
     State#state{monitors = dict:store(MRef, ClientId, Monitors)}.
 
 erase_monitor(MRef, State = #state{monitors = Monitors}) ->
+    erlang:demonitor(MRef, [flush]),
     State#state{monitors = dict:erase(MRef, Monitors)}.