When running jtreg test gc/TestAllocHumongousFragment.java#generational , the following Internal error was triggered :

#  Internal Error (shenandoahVerifier.cpp:110), pid=68218, tid=68234
#  Error: Before Full GC, Reachable; Object start should be within the region

Referenced from:
  interior location: 0x00000000c067b9fc
  0x00000000c067b9e8 - klass 0x000002ae00170dd0 [Ljava.lang.Object;
        allocated after mark start
    not after update watermark
        marked strong
        marked weak
    not in collection set
  age: 0
  mark: mark(is_unlocked no_hash age=0)
  region: |   12|R  |O|BTE     c0600000,     c067ba80,     c0680000|TAMS     c0600000|UWM     c067ba80|U   494K|T     0B|G     0B|P     0B|S   494K|L   494K|CP   0

Object:
  0x00000000fc900000 - safe print, no details
  region: | 1938|EC |F|BTE     fc900000,     fc900000,     fc980000|TAMS     fc900000|UWM     fc900000|U     0B|T     0B|G     0B|P     0B|S     0B|L     0B|CP   0

Raw heap memory:
0x00000000fc900000:   00000001 00000000 00172210 0019bb53   ........."..S...
0x00000000fc900010:   00000000 00000000 00000000 00000000   ................
0x00000000fc900020:   00000000 00000000 00000000 00000000   ................
0x00000000fc900030:   00000000 00000000 00000000 00000000   ................
0x00000000fc900040:   00000000 00000000 00000000 00000000   ................
0x00000000fc900050:   00000000 00000000 00000000 00000000   ................
0x00000000fc900060:   00000000 00000000 00000000 00000000   ................
0x00000000fc900070:   00000000 00000000 00000000 00000000   ................

Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x122be08]  VMError::report(outputStream*, bool)+0x28a8  (shenandoahVerifier.cpp:110)
V  [libjvm.so+0x1230b78]  VMError::report_and_die(int, char const*, char const*, char*, Thread*, unsigned char*, void const*, void const*, char const*, int, unsigned long)+0x428  (vmError.cpp:1825)
V  [libjvm.so+0x673c8c]  report_vm_error(char const*, int, char const*, char const*, ...)+0xdc  (debug.cpp:196)
V  [libjvm.so+0x673ce0]  report_vm_error(char const*, int, char const*)+0x30  (debug.cpp:149)
V  [libjvm.so+0xf503e0]  ShenandoahAsserts::print_failure(ShenandoahAsserts::SafeLevel, oopDesc*, void*, oopDesc*, char const*, char const*, char const*, int)+0x220  (shenandoahAsserts.cpp:168)
V  [libjvm.so+0x105c058]  ShenandoahVerifyOopClosure::verify_oop(oopDesc*)+0x618  (shenandoahVerifier.cpp:110)
V  [libjvm.so+0x1063bd0]  void OopOopIterateDispatch<ShenandoahVerifyOopClosure>::Table::oop_oop_iterate<ObjArrayKlass, narrowOop>(ShenandoahVerifyOopClosure*, oopDesc*, Klass*)+0x370  (shenandoahVerifier.cpp:332)
V  [libjvm.so+0x105e160]  ShenandoahVerifierReachableTask::work(unsigned int)+0x320  (iterator.inline.hpp:300)
V  [libjvm.so+0x1278014]  WorkerThread::run()+0xe4  (workerThread.cpp:69)
V  [libjvm.so+0x116ae1c]  Thread::call_run()+0xec  (thread.cpp:231)
V  [libjvm.so+0xe15040]  thread_native_entry(Thread*)+0x130  (os_linux.cpp:875)
C  [libc.so.6+0xb2014]  start_thread+0x184

The issue was seen on Linux ppc64le.  On Linux x86_64 we saw no such crash but quite a few timeouts when running this test.