VM crashes when -XX:ParallelGCThreads=0 is used

Here is the report:
;; Using jvm: "/net/jse-st01.russia/export4/java/re/jdk/7/promoted/ea/b84/binaries/linux-x64/fastdebug/jre/lib/amd64/server/libjvm.so"
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/BUILD_AREA/jdk7/hotspot/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp:1286), pid=5662, tid=140352559626512
# Error: assert(ParallelGCThreads > 1 || n_yielded() == _hrrs->occupied(),"Should have yielded all the cards in the rem set (in the non-par case).")
#
# JRE version: 7.0-b84
# Java VM: Java HotSpot(TM) 64-Bit Server VM (17.0-b09-fastdebug mixed mode linux-amd64 )
# If you would like to submit a bug report, please visit:
# http://java.sun.com/webapps/bugreport/crash.jsp
#

--------------- T H R E A D ---------------

Current thread (0x000000000249a000): VMThread [stack: 0x00007fa66065b000,0x00007fa66075c000] [id=5668]

Stack: [0x00007fa66065b000,0x00007fa66075c000], sp=0x00007fa660751320, free space=3d80000000000000018k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0xa061af];; VMError::report(outputStream*)+0x138f
V [libjvm.so+0xa0654a];; VMError::report_and_die()+0x2da
V [libjvm.so+0x462b7e];; report_assertion_failure(char const*, int, char const*)+0x6e
V [libjvm.so+0x56f91a];; HeapRegionRemSetIterator::has_next(unsigned long&)+0xea
V [libjvm.so+0x521c26];; ScanRSClosure::doHeapRegion(HeapRegion*)+0x136
V [libjvm.so+0x4f8ff8];; G1CollectedHeap::collection_set_iterate_from(HeapRegion*, HeapRegionClosure*)+0x98
V [libjvm.so+0x51e241];; HRInto_G1RemSet::scanRS(OopsInHeapRegionClosure*, int)+0x171
V [libjvm.so+0x51e915];; HRInto_G1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure*, int)+0x3f5
V [libjvm.so+0x5035a4];; G1CollectedHeap::g1_process_strong_roots(bool, SharedHeap::ScanningOption, OopClosure*, OopsInHeapRegionClosure*, OopsInHeapRegionClosure*, OopsInGenClosure*, int)+0x334
V [libjvm.so+0x50dd14];; G1ParTask::work(int)+0x4a4
V [libjvm.so+0x503aae];; G1CollectedHeap::evacuate_collection_set()+0x28e
V [libjvm.so+0x5011fd];; G1CollectedHeap::do_collection_pause_at_safepoint()+0xc5d
V [libjvm.so+0xa22bba];; VM_G1IncCollectionPause::doit()+0xca
V [libjvm.so+0xa21adf];; VM_Operation::evaluate()+0x8f
V [libjvm.so+0xa1fc10];; VMThread::evaluate_operation(VM_Operation*)+0xc0
V [libjvm.so+0xa205ab];; VMThread::loop()+0x24b
V [libjvm.so+0xa20afe];; VMThread::run()+0xae
V [libjvm.so+0x83b380];; java_start(Thread*)+0xf0
# Internal Error (/tmp/jprt/P1/B/045005.jcoomes/source/src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp:1284), pid=30925, tid=3037698960
# assert(ParallelGCThreads > 1 || n_yielded() == _hrrs->occupied()) failed: Should have yielded all the cards in the rem set (in the non-par case).
#
# JRE version: 7.0-b99
# Java VM: OpenJDK Client VM (19.0-b02-201007020450.jcoomes.gc-tasks-fastdebug mixed mode linux-x86 )
# If you would like to submit a bug report, please visit:
# http://java.sun.com/webapps/bugreport/crash.jsp
#

--------------- T H R E A D ---------------

Current thread (0x0912a800): GCTaskThread [stack: 0x00000000,0x00000000] [id=30929]

Stack:
[error occurred during error reporting (printing stack bounds), id 0xe0000000]

Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x6dfa17];; _ZN7VMError6reportEP12outputStream+0x1207
V [libjvm.so+0x6dfc9b];; _ZN7VMError14report_and_dieEv+0x18b
V [libjvm.so+0x2e0a98];; _Z15report_vm_errorPKciS0_S0_+0x68
V [libjvm.so+0x6dfacf];; _ZN7VMError6reportEP12outputStream+0x12bf
V [libjvm.so+0x6dfc9b];; _ZN7VMError14report_and_dieEv+0x18b
V [libjvm.so+0x2e0a98];; _Z15report_vm_errorPKciS0_S0_+0x68
V [libjvm.so+0x37f1d4];; _ZN24HeapRegionRemSetIterator8has_nextERj+0xf4
V [libjvm.so+0x34db16];; _ZN13ScanRSClosure12doHeapRegionEP10HeapRegion+0x1a6
V [libjvm.so+0x3289ab];; _ZN15G1CollectedHeap27collection_set_iterate_fromEP10HeapRegionP17HeapRegionClosure+0x15b
V [libjvm.so+0x34ab4d];; _ZN15HRInto_G1RemSet6scanRSEP23OopsInHeapRegionClosurei+0xfd
V [libjvm.so+0x34b1a0];; _ZN15HRInto_G1RemSet27oops_into_collection_set_doEP23OopsInHeapRegionClosurei+0x1f0
V [libjvm.so+0x32689c];; _ZN15G1CollectedHeap23g1_process_strong_rootsEbN10SharedHeap14ScanningOptionEP10OopClosureP23OopsInHeapRegionClosureP16OopsInGenClosurei+0x29c
V [libjvm.so+0x33b381];; _ZN9G1ParTask4workEi+0x9b1
V [libjvm.so+0x7090c0];; _ZN10GangWorker4loopEv+0x130
V [libjvm.so+0x7079e8];; _ZN10GangWorker3runEv+0x18
V [libjvm.so+0x59eaa9];; _ZL10java_startP6Thread+0xf9
C [libpthread.so.0+0x5832]



http://sqeweb.sfbay.sun.com/nfs/results/vm/gtee/JDK7/NIGHTLY/VM/2010-07-06/G1_GC_Baseline/vm/linux-i586/client/mixed/linux-i586_client_mixed_vm.gc.testlist_129AB4939B1/ResultDir/Churn4//hs_err_pid30925.log


Rerun file:
http://sqeweb.sfbay.sun.com/nfs/results/vm/gtee/JDK7/NIGHTLY/VM/2010-07-06/G1_GC_Baseline/vm/linux-i586/client/mixed/linux-i586_client_mixed_vm.gc.testlist_129AB4939B1/ResultDir/Churn4/rerun.sh
Both reports above are on Linux (one 32-bit client and the other 64-bit server).
I don't know whether that is mere coincidence. I have not tried reproducing it
anywhere yet.
gc.memory.Churn.Churn4.Churn4
gc/memory/Churi/Chrun4/Churn4
http://sqeweb.sfbay.sun.com/nfs/tools/gtee/results/JDK7/NIGHTLY/VM/2010-07-29/G1_GC_Baseline/vm/linux-i586/server/mixed/linux-i586_vm_server_mixed_vm.gc.testlist/ResultDir/Churn1//hs_err_pid11724.log

gc.memory.Churn.Churn1.Churn1
gc/memory/Churn/Churn1/Churn1