diff --git a/service/process.go b/service/process.go
index bbdc5f3..945aa1a 100644
--- a/service/process.go
+++ b/service/process.go
@@ -174,7 +174,7 @@ func (this *service) processIncoming(msg message.Message) error {
 
 	case *message.DisconnectMessage:
 		// For DISCONNECT message, we should quit
-		this.sess.Cmsg.SetWillFlag(false)
+		this.sess.SetWillFlag(false)
 		return errDisconnect
 
 	default:
diff --git a/service/service.go b/service/service.go
index cd23342..a3de565 100644
--- a/service/service.go
+++ b/service/service.go
@@ -235,7 +235,7 @@ func (this *service) stop() {
 	}
 
 	// Publish will message if WillFlag is set. Server side only.
-	if !this.client && this.sess.Cmsg.WillFlag() {
+	if !this.client && this.sess.WillFlag() {
 		glog.Infof("(%s) service/stop: connection unexpectedly closed. Sending Will.", this.cid())
 		this.onPublish(this.sess.Will)
 	}
@@ -246,7 +246,7 @@ func (this *service) stop() {
 	}
 
 	// Remove the session from session store if it's suppose to be clean session
-	if this.sess.Cmsg.CleanSession() && this.sessMgr != nil {
+	if this.sess.CleanSession() && this.sessMgr != nil {
 		this.sessMgr.Del(this.sess.ID())
 	}
 
diff --git a/sessions/session.go b/sessions/session.go
index 386d2f7..1745c47 100644
--- a/sessions/session.go
+++ b/sessions/session.go
@@ -46,7 +46,7 @@ type Session struct {
 	Pingack *Ackqueue
 
 	// cmsg is the CONNECT message
-	Cmsg *message.ConnectMessage
+	cmsg *message.ConnectMessage
 
 	// Will message to publish if connect is closed unexpectedly
 	Will *message.PublishMessage
@@ -201,3 +201,20 @@ func (this *Session) Topics() ([]string, []byte, error) {
 func (this *Session) ID() string {
 	return string(this.Cmsg.ClientId())
 }
+func (this *Session) WillFlag() bool {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+	return this.cmsg.WillFlag()
+}
+
+func (this *Session) SetWillFlag(v bool) {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+	this.cmsg.SetWillFlag(v)
+}
+
+func (this *Session) CleanSession() bool {
+	this.mu.Lock()
+	defer this.mu.Unlock()
+	return this.cmsg.CleanSession()
+}
diff --git a/topics/memtopics.go b/topics/memtopics.go
index 3cddfa9..d316e88 100644
--- a/topics/memtopics.go
+++ b/topics/memtopics.go
@@ -125,8 +125,12 @@ func (this *memTopics) Retained(topic []byte, msgs *[]*message.PublishMessage) e
 }
 
 func (this *memTopics) Close() error {
+	this.smu.Lock()
 	this.sroot = nil
+	this.smu.Unlock()
+	this.rmu.Lock()
 	this.rroot = nil
+	this.rmu.Unlock()
 	return nil
 }