diff --git a/core/chain_manager.go b/core/chain_manager.go
index d9ab04a02..9bb14b0cd 100644
--- a/core/chain_manager.go
+++ b/core/chain_manager.go
@@ -496,6 +496,9 @@ func (self *ChainManager) procFutureBlocks() {
 }
 
 func (self *ChainManager) InsertChain(chain types.Blocks) error {
+	self.mu.Lock()
+	defer self.mu.Unlock()
+
 	// A queued approach to delivering events. This is generally faster than direct delivery and requires much less mutex acquiring.
 	var (
 		queue      = make([]interface{}, len(chain))
@@ -543,55 +546,51 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
 
 		block.Td = new(big.Int).Set(CalculateTD(block, self.GetBlock(block.ParentHash())))
 
-		self.mu.Lock()
-		{
-			cblock := self.currentBlock
-			// Write block to database. Eventually we'll have to improve on this and throw away blocks that are
-			// not in the canonical chain.
-			self.write(block)
-			// Compare the TD of the last known block in the canonical chain to make sure it's greater.
-			// At this point it's possible that a different chain (fork) becomes the new canonical chain.
-			if block.Td.Cmp(self.td) > 0 {
-				//if block.Header().Number.Cmp(new(big.Int).Add(cblock.Header().Number, common.Big1)) < 0 {
-				if block.Number().Cmp(cblock.Number()) <= 0 {
-					chash := cblock.Hash()
-					hash := block.Hash()
+		cblock := self.currentBlock
+		// Write block to database. Eventually we'll have to improve on this and throw away blocks that are
+		// not in the canonical chain.
+		self.write(block)
+		// Compare the TD of the last known block in the canonical chain to make sure it's greater.
+		// At this point it's possible that a different chain (fork) becomes the new canonical chain.
+		if block.Td.Cmp(self.td) > 0 {
+			//if block.Header().Number.Cmp(new(big.Int).Add(cblock.Header().Number, common.Big1)) < 0 {
+			if block.Number().Cmp(cblock.Number()) <= 0 {
+				chash := cblock.Hash()
+				hash := block.Hash()
 
-					if glog.V(logger.Info) {
-						glog.Infof("Split detected. New head #%v (%x) TD=%v, was #%v (%x) TD=%v\n", block.Header().Number, hash[:4], block.Td, cblock.Header().Number, chash[:4], self.td)
-					}
-					// during split we merge two different chains and create the new canonical chain
-					self.merge(self.getBlockByNumber(block.NumberU64()), block)
-
-					queue[i] = ChainSplitEvent{block, logs}
-					queueEvent.splitCount++
+				if glog.V(logger.Info) {
+					glog.Infof("Split detected. New head #%v (%x) TD=%v, was #%v (%x) TD=%v\n", block.Header().Number, hash[:4], block.Td, cblock.Header().Number, chash[:4], self.td)
 				}
+				// during split we merge two different chains and create the new canonical chain
+				self.merge(self.getBlockByNumber(block.NumberU64()), block)
 
-				self.setTotalDifficulty(block.Td)
-				self.insert(block)
-
-				jsonlogger.LogJson(&logger.EthChainNewHead{
-					BlockHash:     block.Hash().Hex(),
-					BlockNumber:   block.Number(),
-					ChainHeadHash: cblock.Hash().Hex(),
-					BlockPrevHash: block.ParentHash().Hex(),
-				})
-
-				self.setTransState(state.New(block.Root(), self.stateDb))
-				self.txState.SetState(state.New(block.Root(), self.stateDb))
-
-				queue[i] = ChainEvent{block, logs}
-				queueEvent.canonicalCount++
-
-				if glog.V(logger.Debug) {
-					glog.Infof("inserted block #%d (%d TXs %d UNCs) (%x...)\n", block.Number(), len(block.Transactions()), len(block.Uncles()), block.Hash().Bytes()[0:4])
-				}
-			} else {
-				queue[i] = ChainSideEvent{block, logs}
-				queueEvent.sideCount++
+				queue[i] = ChainSplitEvent{block, logs}
+				queueEvent.splitCount++
 			}
+
+			self.setTotalDifficulty(block.Td)
+			self.insert(block)
+
+			jsonlogger.LogJson(&logger.EthChainNewHead{
+				BlockHash:     block.Hash().Hex(),
+				BlockNumber:   block.Number(),
+				ChainHeadHash: cblock.Hash().Hex(),
+				BlockPrevHash: block.ParentHash().Hex(),
+			})
+
+			self.setTransState(state.New(block.Root(), self.stateDb))
+			self.txState.SetState(state.New(block.Root(), self.stateDb))
+
+			queue[i] = ChainEvent{block, logs}
+			queueEvent.canonicalCount++
+
+			if glog.V(logger.Debug) {
+				glog.Infof("inserted block #%d (%d TXs %d UNCs) (%x...)\n", block.Number(), len(block.Transactions()), len(block.Uncles()), block.Hash().Bytes()[0:4])
+			}
+		} else {
+			queue[i] = ChainSideEvent{block, logs}
+			queueEvent.sideCount++
 		}
-		self.mu.Unlock()
 
 		stats.processed++