diff -r ca7c15a01229 -r a1d5f532838d src/share/vm/runtime/globals.hpp
--- a/src/share/vm/runtime/globals.hpp	Mon May 02 07:08:53 2011 -0700
+++ b/src/share/vm/runtime/globals.hpp	Fri Apr 29 09:11:03 2011 +0200
@@ -1824,7 +1824,7 @@
   develop(bool, VerifyBlockOffsetArray, false,                              \
           "Do (expensive!) block offset array verification")                \
                                                                             \
-  product(bool, BlockOffsetArrayUseUnallocatedBlock, false,                 \
+  diagnostic(bool, BlockOffsetArrayUseUnallocatedBlock, false,              \
           "Maintain _unallocated_block in BlockOffsetArray"                 \
           " (currently applicable only to CMS collector)")                  \
                                                                             \