diff -r 6dce0126f44e -r 54a56bbaf95b src/share/vm/runtime/globals.hpp
--- a/src/share/vm/runtime/globals.hpp	Wed May 04 11:04:45 2011 -0400
+++ b/src/share/vm/runtime/globals.hpp	Fri May 06 09:45:18 2011 +0200
@@ -1827,7 +1827,7 @@
   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)")                  \
                                                                             \