Customer is running on a amd64 solaris jboss+gridgain+latest system patches and 6u20 crashes with stack

Stack: [0xfffffd7de4967000,0xfffffd7de4a67000], sp=0xfffffd7de4a66700, free space=3fd0000000000000001k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x3486ba] void MarkSweep::MarkAndPushClosure::do_oop(oopDesc**)+0x1a
V [libjvm.so+0x3a634f] void OopMapCache::oop_iterate(OopClosure*)+0x2f
V [libjvm.so+0x360f20] void instanceKlassKlass::oop_follow_contents(oopDesc*)+0xa70
V [libjvm.so+0x3f363b] void MarkSweep::follow_stack()+0x12b
V [libjvm.so+0xa10cd8] void PSMarkSweep::mark_sweep_phase1(bool)+0xa8
V [libjvm.so+0xa10028] void PSMarkSweep::invoke_no_policy(bool)+0x548
V [libjvm.so+0xa0fabd] void PSMarkSweep::invoke(bool)+0x9d
V [libjvm.so+0x4c85be] void VM_ParallelGCSystemGC::doit()+0x9e
V [libjvm.so+0x4023d4] void VM_Operation::evaluate()+0x84
V [libjvm.so+0x4025ed] void VMThread::evaluate_operation(VM_Operation*)+0xbd
V [libjvm.so+0x543abb] void VMThread::loop()+0x3ab
V [libjvm.so+0x542ccf] void VMThread::run()+0x7f
V [libjvm.so+0x9e3449] java_start+0x1f9
C [libc.so.1+0xd704b] _thr_slot_offset+0x31b
C [libc.so.1+0xd7280] _thr_slot_offset+0x550

VM_Operation (0xfffffd7de3b367b0): ParallelGCSystemGC, mode: safepoint, requested by thread 0x0000000000f56800
...
VM Arguments:
jvm_args: -Dprogram.name=run.sh -XX:MaxPermSize=512m -XX:PermSize=512m -XX:+UseParallelGC -XX:ParallelGCThreads=2 -Xms4000m -Xmx8000m