The following test failed in the JDK18 CI:

gc/TestStackOverflow.java

Here's a snippet from the log file:

910000
920000
930000
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc: SuppressErrorAt=/oop.inline.hpp:292
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/opt/mach5/mesos/work_dir/slaves/35546316-ed70-4084-8244-d672e7734fd1-S13245/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/f172a040-6211-41cc-8a52-80123c8c09b0/runs/342e0b90-31a3-4303-83f5-59e801f89347/workspace/open/src/hotspot/share/oops/oop.inline.hpp:292), pid=2151569, tid=2151591
# assert(is_forwarded()) failed: only decode when actually forwarded
#
# JRE version: Java(TM) SE Runtime Environment (18.0+25) (fastdebug build 18-ea+25-1638)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 18-ea+25-1638, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-aarch64)
# Problematic frame:
# V [libjvm.so+0xac50e0] oopDesc::forwardee() const+0x50
#
# Core dump will be written. Default location: Core dumps may be processed with "/opt/core.sh %p" (or dumping to /opt/mach5/mesos/work_dir/slaves/369e65c9-433d-40ff-b6a0-b4e65701097a-S4636/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/b4da8de1-6d7b-4490-9328-caede55f5fd1/runs/35186a5a-256b-4e0f-82e8-977aa3d71fc7/testoutput/test-support/jtreg_open_test_hotspot_jtreg_tier1/scratch/2/core.2151569)
#
# An error report file with more information is saved as:
# /opt/mach5/mesos/work_dir/slaves/369e65c9-433d-40ff-b6a0-b4e65701097a-S4636/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/b4da8de1-6d7b-4490-9328-caede55f5fd1/runs/35186a5a-256b-4e0f-82e8-977aa3d71fc7/testoutput/test-support/jtreg_open_test_hotspot_jtreg_tier1/scratch/2/hs_err_pid2151569.log
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#
----------System.err:(0/0)----------
----------rerun:(33/5407)*----------


Here's the crashing thread's stack:

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

Current thread (0x0000fffd8c009f40): WorkerThread "GC Thread#1" [stack: 0x0000fffd9dc90000,0x0000fffd9de90000] [id=2151591]

Stack: [0x0000fffd9dc90000,0x0000fffd9de90000], sp=0x0000fffd9de8e430, free space=2041k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0xac50e0] oopDesc::forwardee() const+0x50
V [libjvm.so+0xcfcbc0] void G1ParScanThreadState::write_ref_field_post<narrowOop>(narrowOop*, oop)+0x170
V [libjvm.so+0xd00824] void G1ParScanThreadState::do_oop_evac<narrowOop>(narrowOop*)+0x294
V [libjvm.so+0xcfb038] G1ParScanThreadState::trim_queue_to_threshold(unsigned int)+0x308
V [libjvm.so+0xcfb488] G1ParScanThreadState::steal_and_trim_queue(GenericTaskQueueSet<OverflowTaskQueue<ScannerTask, (MEMFLAGS)5, 131072u>, (MEMFLAGS)5>*)+0x3d8
V [libjvm.so+0xd4bc28] G1ParEvacuateFollowersClosure::do_void()+0x158
V [libjvm.so+0xd4c86c] G1EvacuateRegionsTask::evacuate_live_objects(G1ParScanThreadState*, unsigned int)+0x6c
V [libjvm.so+0xd46330] G1EvacuateRegionsBaseTask::work(unsigned int)+0x120
V [libjvm.so+0x19192e0] WorkerThread::run()+0x80
V [libjvm.so+0x17d8558] Thread::call_run()+0xf8
V [libjvm.so+0x15067d4] thread_native_entry(Thread*)+0x104
C [libpthread.so.0+0x7738] start_thread+0x198


The test task's JVM args are: -Xcheck:jni