--- old/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	2020-01-24 15:17:56.217315932 +0100
+++ new/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	2020-01-24 15:17:56.009312440 +0100
@@ -1252,8 +1252,8 @@
         obj = fwd;
       }
       assert(oopDesc::is_oop(obj), "must be a valid oop");
-      if (!_bitmap->is_marked(obj)) {
-        _bitmap->mark(obj);
+      if (!_bitmap->is_marked((HeapWord*) obj)) {
+        _bitmap->mark((HeapWord*) obj);
         _oop_stack->push(obj);
       }
     }