[viewchange] add RLock for m1Payload functions

Signed-off-by: Leo Chen <leo@harmony.one>

consensus/view_change.go

@@ -230,8 +230,8 @@ func (consensus *Consensus) onViewChange(msg *msg_pb.Message) {
 
 	// received enough view change messages, change state to normal consensus
 	if consensus.Decider.IsQuorumAchievedByMask(consensus.vc.GetViewIDBitmap(recvMsg.ViewID)) {
-		consensus.getLogger().Info().Msg("[onViewChange] View Change Message Quorum Reached")
 		consensus.current.SetMode(Normal)
+		consensus.getLogger().Info().Msg("[onViewChange] View Change Message Quorum Reached")
 		consensus.LeaderPubKey = newLeaderKey
 		consensus.ResetState()
 		if consensus.vc.IsM1PayloadEmpty() {

consensus/view_change_construct.go

@@ -438,6 +438,7 @@ func (vc *viewChange) InitPayload(
 }
 
 // isM1PayloadEmpty returns true if m1Payload is not set
+// this is an unlocked internal function call
 func (vc *viewChange) isM1PayloadEmpty() bool {
 	return len(vc.m1Payload) == 0
 }
@@ -458,6 +459,8 @@ func (vc *viewChange) GetViewIDBitmap(viewID uint64) *bls_cosi.Mask {
 
 // GetM1Payload returns the m1Payload
 func (vc *viewChange) GetM1Payload() []byte {
+	vc.vcLock.RLock()
+	defer vc.vcLock.RUnlock()
 	return vc.m1Payload
 }