Forget Unlock in snapshot

core/state/snapshot/iterator.go

@@ -125,8 +125,10 @@ func (it *diffAccountIterator) Account() []byte {
 	blob, ok := it.layer.accountData[it.curHash]
 	if !ok {
 		if _, ok := it.layer.destructSet[it.curHash]; ok {
+			it.layer.lock.RUnlock()
 			return nil
 		}
+		it.layer.lock.RUnlock()
 		panic(fmt.Sprintf("iterator referenced non-existent account: %x", it.curHash))
 	}
 	it.layer.lock.RUnlock()

core/state/snapshot/snapshot.go

@@ -420,6 +420,7 @@ func diffToDisk(bottom *diffLayer) *diskLayer {
 	// Mark the original base as stale as we're going to create a new wrapper
 	base.lock.Lock()
 	if base.stale {
+		base.lock.Unlock()
 		panic("parent disk layer is stale") // we've committed into the same base from two children, boo
 	}
 	base.stale = true