--- a/hotspot/src/share/vm/oops/oop.inline.hpp	Thu Dec 05 15:13:12 2013 -0800
+++ b/hotspot/src/share/vm/oops/oop.inline.hpp	Mon Dec 02 10:26:14 2013 +0100
@@ -490,9 +490,9 @@
   return size_given_klass(klass());
 }
 
-inline void update_barrier_set(void* p, oop v) {
+inline void update_barrier_set(void* p, oop v, bool release = false) {
   assert(oopDesc::bs() != NULL, "Uninitialized bs in oop!");
-  oopDesc::bs()->write_ref_field(p, v);
+  oopDesc::bs()->write_ref_field(p, v, release);
 }
 
 template <class T> inline void update_barrier_set_pre(T* p, oop v) {
@@ -505,7 +505,10 @@
   } else {
     update_barrier_set_pre(p, v);
     oopDesc::encode_store_heap_oop(p, v);
-    update_barrier_set((void*)p, v);  // cast away type
+    // always_do_update_barrier == false =>
+    // Either we are at a safepoint (in GC) or CMS is not used. In both
+    // cases it's unnecessary to mark the card as dirty with release sematics.
+    update_barrier_set((void*)p, v, false /* release */);  // cast away type
   }
 }
 
@@ -513,7 +516,12 @@
   update_barrier_set_pre((T*)p, v);   // cast away volatile
   // Used by release_obj_field_put, so use release_store_ptr.
   oopDesc::release_encode_store_heap_oop(p, v);
-  update_barrier_set((void*)p, v);    // cast away type
+  // When using CMS we must mark the card corresponding to p as dirty
+  // with release sematics to prevent that CMS sees the dirty card but
+  // not the new value v at p due to reordering of the two
+  // stores. Note that CMS has a concurrent precleaning phase, where
+  // it reads the card table while the Java threads are running.
+  update_barrier_set((void*)p, v, true /* release */);    // cast away type
 }
 
 // Should replace *addr = oop assignments where addr type depends on UseCompressedOops