diff --git a/tests/camera2/camera2_utils.h b/tests/camera2/camera2_utils.h
index a01bae2..274ee76 100644
--- a/tests/camera2/camera2_utils.h
+++ b/tests/camera2/camera2_utils.h
@@ -65,7 +65,7 @@
 
   private:
     status_t freeBuffers(List<camera_metadata_t*>::iterator start,
-                         List<camera_metadata_t*>::iterator end);
+                         const List<camera_metadata_t*>::iterator& end);
 
     camera2_device_t *mDevice;