diff -r 7fcd5f39bd7a -r be3f9c242c9d src/share/vm/runtime/globals.hpp
--- a/src/share/vm/runtime/globals.hpp	Sat Aug 14 00:47:52 2010 -0700
+++ b/src/share/vm/runtime/globals.hpp	Mon Aug 16 15:58:42 2010 -0700
@@ -1712,7 +1712,7 @@
   develop(bool, VerifyBlockOffsetArray, false,                              \
           "Do (expensive!) block offset array verification")                \
                                                                             \
-  product(bool, BlockOffsetArrayUseUnallocatedBlock, trueInDebug,           \
+  product(bool, BlockOffsetArrayUseUnallocatedBlock, false,                 \
           "Maintain _unallocated_block in BlockOffsetArray"                 \
           " (currently applicable only to CMS collector)")                  \
                                                                             \