While testing with ParallelGCThreads==0, I ran into the following crash:

2012-10-01T14:32:03.781-0700: 4.018: [GC pause (young)4.029: [SoftReference, 0 refs, 0.0000097 secs]4.029: [WeakReference, 1 refs, 0.0000110 secs]4.029: [FinalReference, 28 refs, 0.0003202 secs]4.029: [PhantomReference, 0 refs, 0.0000061 secs]4.029: [JNI Weak Reference, 0 refs, 0.0000089 secs]#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGFPE (0x8) at pc=0xfe386082, pid=12513, tid=6
#
# JRE version: Java(TM) SE Runtime Environment (7.0-b147)
# Java VM: Java HotSpot(TM) Server VM (25.0-b04-internal-jvmg mixed mode solaris-x86 )
# Problematic frame:
# V [libjvm.so+0xb86082] void PLABStats::adjust_desired_plab_sz()+0x182
#
# Core dump written. Default location: /export/GC-TEST-SUITES/gcbasher/core or core.12513
#
# An error report file with more information is saved as:
# /export/GC-TEST-SUITES/gcbasher/hs_err_pid12513.log
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
#
Current thread is 6
Dumping core ...

with the following stack trace:

Stack: [0xe66fe000,0xe677e000], sp=0xe677d674, free space=509k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0xb86082] void PLABStats::adjust_desired_plab_sz()+0x182
V [libjvm.so+0x788e27] void G1CollectedHeap::release_gc_alloc_regions()+0x57
V [libjvm.so+0x78b7c3] void G1CollectedHeap::evacuate_collection_set()+0x503
V [libjvm.so+0x788297] bool G1CollectedHeap::do_collection_pause_at_safepoint(double)+0x967
V [libjvm.so+0xdb2e58] void VM_G1IncCollectionPause::doit()+0x1b8
V [libjvm.so+0xdafccd] void VM_Operation::evaluate()+0x7d
V [libjvm.so+0xdad7cc] void VMThread::evaluate_operation(VM_Operation*)+0x9c
V [libjvm.so+0xdadda0] void VMThread::loop()+0x4d0
V [libjvm.so+0xdad401] void VMThread::run()+0x111
V [libjvm.so+0xb5d950] java_start+0x210

during the first GC.