diff --git a/miner/worker.go b/miner/worker.go
index 12ed656268..ffb25d9f56 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -313,6 +313,10 @@ func (self *worker) makeCurrent() {
 	}
 
 	parent := self.chain.GetBlock(current.block.ParentHash())
+	if parent == nil {
+		// in case geth quits the blockchain db can be closed and this returns nil
+		return
+	}
 	current.coinbase.SetGasPool(core.CalcGasLimit(parent))
 
 	self.current = current