diff --git a/cache/blobs_linux.go b/cache/blobs_linux.go
index 07c5bcffc9099..8ba03c1771ce6 100644
--- a/cache/blobs_linux.go
+++ b/cache/blobs_linux.go
@@ -45,6 +45,9 @@ func (sr *immutableRef) tryComputeOverlayBlob(ctx context.Context, lower, upper
 	}
 	defer func() {
 		if cw != nil {
+			// after commit succ cw will be set to to nil, if cw isn't nil, error
+			// happened before commit, we should drop the content already written
+			cw.Truncate(0)
 			if cerr := cw.Close(); cerr != nil {
 				bklog.G(ctx).WithError(cerr).Warnf("failed to close writer %q", ref)
 			}