While testing the changes for 6814437 using the GC test suite, with dacapo and -XX:ParallelGCThreads=0 I ran into several failures similar to that seen in 6930581. I also ran into a few instances of the following assert:

# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc:  SuppressErrorAt=/instanceKlass.cpp:1475
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  Internal Error (/export/workspaces/reference/hotspot/src/share/vm/oops/instanceKlass.cpp:1475), pid=23224, tid=7
#  assert(Universe::heap()->is_in_closed_subset(o)) failed: should be in closed
#

To verify if the culprit was the changes associated with 6814437 I ran with a reference VM and saw very similar results, i.e. most of the failures were that seen in 6930581 while 1 or 2 were the assert at instanceKlass.cpp:1475.