diff --git a/core/state/snapshot/snapshot.go b/core/state/snapshot/snapshot.go
index 89a4c16c20..4eee5d8037 100644
--- a/core/state/snapshot/snapshot.go
+++ b/core/state/snapshot/snapshot.go
@@ -666,6 +666,9 @@ func diffToDisk(bottom *diffLayer) *diskLayer {
 
 // Release releases resources
 func (t *Tree) Release() {
+	t.lock.Lock()
+	defer t.lock.Unlock()
+
 	if dl := t.disklayer(); dl != nil {
 		dl.Release()
 	}