--- old/src/share/vm/gc/parallel/mutableSpace.hpp	2016-09-12 15:41:06.890114503 +0200
+++ new/src/share/vm/gc/parallel/mutableSpace.hpp	2016-09-12 15:41:06.782114498 +0200
@@ -51,7 +51,7 @@
   MemRegion _last_setup_region;
   size_t _alignment;
  protected:
-  HeapWord* _top;
+  HeapWord* volatile _top;
 
   MutableSpaceMangler* mangler() { return _mangler; }
 
@@ -69,7 +69,7 @@
   HeapWord* top() const                    { return _top;    }
   virtual void set_top(HeapWord* value)    { _top = value;   }
 
-  HeapWord** top_addr()                    { return &_top; }
+  HeapWord* volatile* top_addr()                    { return &_top; }
   HeapWord** end_addr()                    { return &_end; }
 
   virtual void set_bottom(HeapWord* value) { _bottom = value; }