diff --git a/mmtk/src/object_model.rs b/mmtk/src/object_model.rs
index ad09024..c1650a9 100644
--- a/mmtk/src/object_model.rs
+++ b/mmtk/src/object_model.rs
@@ -99,7 +99,7 @@ impl ObjectModel<JikesRVM> for VMObjectModel {
         }
 
         let start = Self::object_start_ref(to);
-        fill_alignment_gap(region, start);
+        fill_alignment_gap::<JikesRVM>(region, start);
 
         start + bytes
     }
diff --git a/repos/mmtk-core b/repos/mmtk-core
index 6a70cb9..4af50fc 160000
--- a/repos/mmtk-core
+++ b/repos/mmtk-core
@@ -1 +1 @@
-Subproject commit 6a70cb9dc7c949d1d714b30718dc8048341a2585
+Subproject commit 4af50fc25760a93041bdc53a62fe89d943991328