diff --git a/miner/worker.go b/miner/worker.go
index 01f631fa03..602eb708d8 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -346,7 +346,11 @@ func (self *worker) wait() {
 			for _, log := range work.state.Logs() {
 				log.BlockHash = block.Hash()
 			}
+			
+                        self.currentMu.Lock()
 			stat, err := self.chain.WriteBlockWithState(block, work.receipts, work.state)
+                        self.currentMu.Unlock()
+			
 			if err != nil {
 				log.Error("Failed writing block to chain", "err", err)
 				continue