The following test failed in the JDK18 CI:

vmTestbase/nsk/jvmti/RedefineClasses/StressRedefineWithoutBytecodeCorruption/TestDescription.java

Here's a snippet from the log file:

[273.575s][trace][redefine,class,iklass,purge] previous version stats: live=32, deleted=1
[273.575s][trace][redefine,class,iklass,add ] scratch class added; one of its methods is on_stack.
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc: SuppressErrorAt=/jvmtiRedefineClasses.cpp:155
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/opt/mach5/mesos/work_dir/slaves/35546316-ed70-4084-8244-d672e7734fd1-S13253/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/a29dbdc8-d4b1-441d-bd87-8509bf4f3b99/runs/335c866a-b223-4ddd-a8da-d156bdb71db5/workspace/open/src/hotspot/share/prims/jvmtiRedefineClasses.cpp:155), pid=2742125, tid=2742507
# assert(def_ik->is_being_redefined()) failed: should be being redefined to get here
#
# JRE version: Java(TM) SE Runtime Environment (18.0+22) (fastdebug build 18-ea+22-1368)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 18-ea+22-1368, compiled mode, sharing, compressed oops, compressed class ptrs, g1 gc, linux-aarch64)
# Problematic frame:
# V [libjvm.so+0x118073c] VM_RedefineClasses::unlock_classes()+0x2cc
#
# 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/a2dc162d-743b-4800-9e92-31f85abb45b1-S33720/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/25065e51-582f-41ab-9753-e9c384c77bf7/runs/557e56f4-ee33-477c-8b83-d62f63b6b6b5/testoutput/test-support/jtreg_open_test_hotspot_jtreg_vmTestbase_nsk_jvmti_quick/scratch/0/core.2742125)
#
# An error report file with more information is saved as:
# /opt/mach5/mesos/work_dir/slaves/a2dc162d-743b-4800-9e92-31f85abb45b1-S33720/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/25065e51-582f-41ab-9753-e9c384c77bf7/runs/557e56f4-ee33-477c-8b83-d62f63b6b6b5/testoutput/test-support/jtreg_open_test_hotspot_jtreg_vmTestbase_nsk_jvmti_quick/scratch/0/hs_err_pid2742125.log
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#
<<<<<<<< RedefineClasses() is successfully done
>>>>>>>> Invoke RedefineClasses():
new class byte count=2286
----------System.err:(0/0)----------
----------rerun:(45/8571)*----------

Here's the crashing thread's stack:

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

Current thread (0x0000fffd60133a90): JavaThread "Thread-22" [_thread_in_vm, id=2742507, stack(0x0000fffd03c00000,0x0000fffd03e00000)]

Stack: [0x0000fffd03c00000,0x0000fffd03e00000], sp=0x0000fffd03dfdfa0, free space=2039k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x118073c] VM_RedefineClasses::unlock_classes()+0x2cc
V [libjvm.so+0x1182564] VM_RedefineClasses::doit_epilogue()+0x14
V [libjvm.so+0x186bcc8] VMThread::execute(VM_Operation*)+0xa8
V [libjvm.so+0x11450cc] JvmtiEnv::RedefineClasses(int, jvmtiClassDefinition const*)+0x6c
V [libjvm.so+0x10e4054] jvmti_RedefineClasses+0x114
C [libstressRedefine.so+0xbf70] Java_nsk_jvmti_RedefineClasses_StressRedefine_makeRedefinition+0xe0
J 9328 nsk.jvmti.RedefineClasses.StressRedefine.makeRedefinition(ILjava/lang/Class;[B)I (0 bytes) @ 0x0000fffdbd141f64 [0x0000fffdbd141ec0+0x00000000000000a4]
C 0x0000fffd6b646af7

Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
J 9328 nsk.jvmti.RedefineClasses.StressRedefine.makeRedefinition(ILjava/lang/Class;[B)I (0 bytes) @ 0x0000fffdbd141f64 [0x0000fffdbd141ec0+0x00000000000000a4]
j nsk.jvmti.RedefineClasses.StressRedefine$Worker.run()V+55
J 1893 c2 java.lang.Thread.run()V java.base@18-ea (17 bytes) @ 0x0000fffdbc46abb0 [0x0000fffdbc46ab40+0x0000000000000070]
v ~StubRoutines::call_stub


This test also has another unresolved bug:

JDK-8272800 vmTestbase/nsk/jvmti/RedefineClasses/StressRedefineWithoutBytecodeCorruption/TestDescription.java timing out