src/hotspot/share/gc/shared/collectedHeap.cpp

@@ -227,11 +227,13 @@
  
    if (!is_in(object)) {
      return false;
    }
  
-   if (!Metaspace::contains(object->klass_without_asserts())) {
+   // With compact headers, we can't safely access the class, due
+   // to possibly forwarded objects.
+   if (!UseCompactObjectHeaders && !Metaspace::contains(object->klass_without_asserts())) {
      return false;
    }
  
    return true;
  }