Happens while inspecting the heap during Dcmd: GC.class_stats

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/opt/jprt/T/P1/205639.cccheung/s/hotspot/src/share/vm/runtime/synchronizer.cpp:581), pid=13170, tid=140633204123392
# assert(Universe::verify_in_progress() || !SafepointSynchronize::is_at_safepoint()) failed: invariant
#
# JRE version: Java(TM) SE Runtime Environment (9.0) (build 1.9.0-internal-fastdebug-201410072056.cccheung.jdk9-hs-rt-b00)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (1.9.0-internal-fastdebug-201410072056.cccheung.jdk9-hs-rt-b00 mixed mode linux-amd64 compressed oops)
# Core dump written. Default location: /scratch/local/aurora/sandbox/results/workDir/com/sun/management/DiagnosticCommandMBean/DcmdMBeanPermissionsTest/core or core.13170
#
# If you would like to submit a bug report, please visit:
# http://bugreport.sun.com/bugreport/crash.jsp
#

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

Current thread (0x00007fe7d818c000): VMThread [stack: 0x00007fe7b81ce000,0x00007fe7b82cf000] [id=13326]

Stack: [0x00007fe7b81ce000,0x00007fe7b82cf000], sp=0x00007fe7b82ccf40, free space=1019k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x10874a1] VMError::report_and_die()+0x151;; VMError::report_and_die()+0x151
V [libjvm.so+0x73d68b] report_vm_error(char const*, int, char const*, char const*)+0x7b;; report_vm_error(char const*, int, char const*, char const*)+0x7b
V [libjvm.so+0xfb148f] ObjectSynchronizer::FastHashCode(Thread*, oop)+0x65f;; ObjectSynchronizer::FastHashCode(Thread*, oop)+0x65f
V [libjvm.so+0xfb1985] ObjectSynchronizer::identity_hash_value_for(Handle)+0x45;; ObjectSynchronizer::identity_hash_value_for(Handle)+0x45
V [libjvm.so+0xdc65b0] oopDesc::slow_identity_hash()+0xc0;; oopDesc::slow_identity_hash()+0xc0
V [libjvm.so+0xbe58a2] Klass::external_name() const+0xf2;; Klass::external_name() const+0xf2
V [libjvm.so+0x8f6a3e] KlassInfoHisto::sort_helper(KlassInfoEntry**, KlassInfoEntry**)+0xce;; KlassInfoHisto::sort_helper(KlassInfoEntry**, KlassInfoEntry**)+0xce

VM_Operation (0x00007fe7b2cea890): GC_HeapInspection, mode: safepoint, requested by thread 0x00007fe7d8363800