This experimental options is not working on G1 GC.
ParallelGC seems to work.

Below callstack is gathered with JDK-13-b21 but a few older versions also show same failure.

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (open/src/hotspot/share/utilities/bitMap.cpp:178), pid=20427, tid=20428
# assert(index < _size) failed: BitMap index out of bounds
#
# JRE version: (13.0+21) (fastdebug build )
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 13-ea+21, mixed mode, aot, tiered, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x691678] BitMap::verify_index(unsigned long) const+0x38
#
# Core dump will be written. Default location: /home/sangheki/Downloads/jdk-13/core
#
# If you would like to submit a bug report, please visit:
# http://bugreport.java.com/bugreport/crash.jsp
#

--------------- S U M M A R Y ------------

Command Line: -XX:+UnlockExperimentalVMOptions -XX:AllocateOldGenAt=. -Xmx128m

Host: Intel(R) Xeon(R) CPU E5-2665 0 @ 2.40GHz, 32 cores, 31G, Ubuntu 16.04.6 LTS
Time: Mon May 20 13:51:06 2019 PDT elapsed time: 0 seconds (0d 0h 0m 0s)

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

Current thread (0x00007f943001f000): JavaThread "Unknown thread" [_thread_in_vm, id=20428, stack(0x00007f94399bf000,0x00007f9439ac0000)]

Stack: [0x00007f94399bf000,0x00007f9439ac0000], sp=0x00007f9439abe940, free space=1022k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x691678] BitMap::verify_index(unsigned long) const+0x38
V [libjvm.so+0xd3e045] HeapRegionManager::is_available(unsigned int) const+0x25
V [libjvm.so+0xd5f598] HeterogeneousHeapRegionManager::find_unavailable_in_range(unsigned int, unsigned int, unsigned int*) const+0x58
V [libjvm.so+0xd60762] HeterogeneousHeapRegionManager::adjust_dram_regions(unsigned int, WorkGang*)+0x152
V [libjvm.so+0xbef0b9] G1CollectedHeap::initialize()+0x6f9
V [libjvm.so+0x16fe104] Universe::initialize_heap()+0x64
V [libjvm.so+0x16fe1e1] universe_init()+0xa1
V [libjvm.so+0xd967b3] init_globals()+0x63
V [libjvm.so+0x16bc376] Threads::create_vm(JavaVMInitArgs*, bool*)+0x296
V [libjvm.so+0xedf9d9] JNI_CreateJavaVM+0x99
C [libjli.so+0x409f] JavaMain+0x7f
C [libjli.so+0x81b9] ThreadJavaMain+0x9