$ CONF=linux-x86_64-server-fastdebug make images run-test TEST=vmTestbase/nsk/jvmti/unit/FollowReferences/ TEST_VM_OPTS="-XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC"

Fails:

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/home/shade/trunks/shenandoah-jdk11/src/hotspot/share/gc/shenandoah/shenandoahForwarding.inline.hpp:47), pid=5542, tid=5555
# Error: Shenandoah assert_correct failed; Forwardee must point to a heap address

Referenced from:
  no interior location recorded (probably a plain heap scan, or detached oop)

Object:
  0x000000070f12b720 - klass 0x0000000800068aa8 nsk.jvmti.unit.FollowReferences.followref001RootTestedClass
        allocated after mark start
        marked
    not in collection set
  mark: marked(0x0000000000000003)
  region: | 4|R |BTE 70f100000, 70f200000, 70f200000|TAMS 70f100000|U 1024K|T 1024K|G 0B|S 0B|L 0B|CP 0|SN 5, 5, 0, 0

Forwardee:
  0x0000000000000000 - safe print, no details


#
# JRE version: OpenJDK Runtime Environment (11.0.5) (fastdebug build 11.0.5-internal+0-adhoc.shade.shenandoah-jdk11)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 11.0.5-internal+0-adhoc.shade.shenandoah-jdk11, mixed mode, tiered, compressed oops, shenandoah gc, linux-amd64)

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

Current thread (0x00007f23cc3cb800): VMThread "VM Thread" [stack: 0x00007f23b275f000,0x00007f23b285f000] [id=5555]

Stack: [0x00007f23b275f000,0x00007f23b285f000], sp=0x00007f23b285ade0, free space=1007k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x194ee24] VMError::report_and_die(int, char const*, char const*, __va_list_tag*, Thread*, unsigned char*, void*, void*, char const*, int, unsigned long)+0x314
V [libjvm.so+0x194fcbf] VMError::report_and_die(Thread*, void*, char const*, int, char const*, char const*, __va_list_tag*)+0x2f
V [libjvm.so+0xadb6f0] report_vm_error(char const*, int, char const*, char const*, ...)+0x100
V [libjvm.so+0x164d38e] ShenandoahAsserts::print_failure(ShenandoahAsserts::SafeLevel, oop, void*, oop, char const*, char const*, char const*, int)+0x45e
V [libjvm.so+0x164dc9a] ShenandoahAsserts::assert_correct(void*, oop, char const*, int)+0x1da
V [libjvm.so+0x1402625] ShenandoahBarrierSet::resolve_forwarded_not_null(oop)+0x45
V [libjvm.so+0x16ce0c0] void ObjectIterateScanRootClosure::do_oop_work<oop>(oop*)+0x70
V [libjvm.so+0xfcd439] JNIHandles::oops_do(OopClosure*)+0xb9
V [libjvm.so+0x16fee0c] ShenandoahHeapIterationRootScanner::roots_do(OopClosure*)+0x47c
V [libjvm.so+0x16c63df] ShenandoahHeap::object_iterate(ObjectClosure*)+0x19f
V [libjvm.so+0x1175787] ObjectMarker::done()+0x317
V [libjvm.so+0x1178f88] VM_HeapWalkOperation::doit()+0x318
V [libjvm.so+0x1993af1] VM_Operation::evaluate()+0x141
V [libjvm.so+0x198ee2e] VMThread::evaluate_operation(VM_Operation*) [clone .constprop.60]+0x18e
V [libjvm.so+0x198f71a] VMThread::loop()+0x50a
V [libjvm.so+0x198fd4b] VMThread::run()+0xcb
V [libjvm.so+0x187ddcd] Thread::call_run()+0x6d
V [libjvm.so+0x147b856] thread_native_entry(Thread*)+0x106