The following test failed in the JDK18 CI:

applications/kitchensink/Kitchensink24HStress.java

Here's a snippet from the log file:

#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00007ff209bdaeec, pid=21948, tid=22024
#
# JRE version: Java(TM) SE Runtime Environment (18.0+17) (build 18-ea+17-965)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (18-ea+17-965, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x6e5eec] G1RegionMarkStatsCache::add_live_words(oopDesc*)+0x15c
#
# 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/ff806ead-2cac-495d-9cbc-62116f99bf14-S13996/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/23ea0fe5-ccc5-4438-bfdd-11ff21b35df5/runs/f8cd76ab-f465-4380-b5fa-5a79c42b8131/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_kitchensink_Kitchensink24HStress_java/scratch/0/core.21948)
#
# JFR recording file will be written. Location: /opt/mach5/mesos/work_dir/slaves/ff806ead-2cac-495d-9cbc-62116f99bf14-S13996/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/23ea0fe5-ccc5-4438-bfdd-11ff21b35df5/runs/f8cd76ab-f465-4380-b5fa-5a79c42b8131/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_kitchensink_Kitchensink24HStress_java/scratch/0/hs_err_pid21948.jfr
#
Unsupported internal testing APIs have been used.

# An error report file with more information is saved as:
# /opt/mach5/mesos/work_dir/slaves/ff806ead-2cac-495d-9cbc-62116f99bf14-S13996/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/23ea0fe5-ccc5-4438-bfdd-11ff21b35df5/runs/f8cd76ab-f465-4380-b5fa-5a79c42b8131/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_kitchensink_Kitchensink24HStress_java/scratch/0/hs_err_pid21948.log
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#
----------System.err:(944/81629)----------


Here's the crashing thread's stack:

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

Current thread (0x00007ff19c016ea0): GCTaskThread "GC Thread#3" [stack: 0x00007ff10f4f4000,0x00007ff10f5f4000] [id=22024]

Stack: [0x00007ff10f4f4000,0x00007ff10f5f4000], sp=0x00007ff10f5f2bd0, free space=1018k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x6e5eec] G1RegionMarkStatsCache::add_live_words(oopDesc*)+0x15c
V [libjvm.so+0x6b24c8] void OopOopIterateDispatch<G1MarkAndPushClosure>::Table::oop_oop_iterate<InstanceRefKlass, narrowOop>(G1MarkAndPushClosure*, oopDesc*, Klass*)+0xf18
V [libjvm.so+0x6b9f6a] G1FullGCMarker::complete_marking(GenericTaskQueueSet<OverflowTaskQueue<oopDesc*, (MEMFLAGS)5, 131072u>, (MEMFLAGS)5>*, GenericTaskQueueSet<OverflowTaskQueue<ObjArrayTask, (MEMFLAGS)5, 131072u>, (MEMFLAGS)5>*, TaskTerminator*)+0xaa
V [libjvm.so+0x6b983e] G1FullGCMarkTask::work(unsigned int)+0xde
V [libjvm.so+0xdf2fbf] GangWorker::loop()+0x5f
V [libjvm.so+0xdf301f]
V [libjvm.so+0xd456f0] Thread::call_run()+0xc0
V [libjvm.so+0xbab221] thread_native_entry(Thread*)+0xe1


siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x0000000000000100