--- a/hotspot/src/share/vm/prims/unsafe.cpp	Wed Jun 04 13:51:09 2008 -0700
+++ b/hotspot/src/share/vm/prims/unsafe.cpp	Thu Jun 05 15:57:56 2008 -0700
@@ -891,6 +891,7 @@
   oop e = JNIHandles::resolve(e_h);
   oop p = JNIHandles::resolve(obj);
   HeapWord* addr = (HeapWord *)index_oop_from_field_offset_long(p, offset);
+  update_barrier_set_pre((void*)addr, e);
   oop res = oopDesc::atomic_compare_exchange_oop(x, addr, e);
   jboolean success  = (res == e);
   if (success)