The following test fails in the JDK16 CI:

runtime/cds/appcds/javaldr/GCDuringDump.java

Here's a snippet from the log file:

[1.342s][warning][cds] Skipping java/util/stream/Collectors$$Lambda$8+0x00000008c005d820: Hidden class
[1.342s][warning][cds] Skipping jdk/internal/module/DefaultRoots$$Lambda$9+0x00000008c005fa00: Hidden class
[1.343s][info   ][cds] Number of classes 1303
[1.343s][info   ][cds]     instance classes   =  1189
[1.343s][info   ][cds]     obj array classes  =   106
[1.343s][info   ][cds]     type array classes =     8
[1.343s][info   ][cds] Updating ConstMethods ... 
[1.356s][info   ][cds] done. 
[1.356s][info   ][cds] Removing unshareable information ... 
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x0000000100e25620, pid=27421, tid=20483
#
# JRE version: Java(TM) SE Runtime Environment (16.0+10) (fastdebug build 16-ea+10-370)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 16-ea+10-370, interpreted mode, tiered, z gc, bsd-amd64)
# Problematic frame:
# V  [libjvm.dylib+0x4d2620]  ClassLoaderData::oops_do(OopClosure*, int, bool)+0x20
#
# Core dump will be written. Default location: core.27421
#
# An error report file with more information is saved as:
# /scratch/mesos/slaves/52628e90-e5e7-4ef3-af97-10d8776d10db-S2020/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/c5d2e18c-957b-4655-a90a-aed7f0152c1e/runs/c9e85a32-daad-48a3-a282-d4c906a0627c/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_runtime/scratch/0/hs_err_pid27421.log
[1.374s][info   ][cds] done. 
[1.374s][info   ][cds] Scanning all metaspace objects ... 
[1.374s][info   ][cds] Allocating RW objects ... 
#
# If you would like to submit a bug report, please visit:
#   https://bugreport.java.com/bugreport/crash.jsp
#
];
 stderr: []
 exitValue = 134

Here's the crashing thread's stack:


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

Current thread (0x00007fb85dc33d60):  GCTaskThread "ZWorker#0" [stack: 0x000070000fa88000,0x000070000fb88000] [id=20483]

Stack: [0x000070000fa88000,0x000070000fb88000],  sp=0x000070000fb81bc0,  free space=998k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.dylib+0x4d2620]  ClassLoaderData::oops_do(OopClosure*, int, bool)+0x20
V  [libjvm.dylib+0x112fb0b]  void OopOopIterateDispatch<ZMarkBarrierOopClosure<false> >::Table::oop_oop_iterate<InstanceKlass, oop>(ZMarkBarrierOopClosure<false>*, oop, Klass*)+0x4b
V  [libjvm.dylib+0x1129b90]  void oopDesc::oop_iterate<ZMarkBarrierOopClosure<false> >(ZMarkBarrierOopClosure<false>*)+0xe0
V  [libjvm.dylib+0x112a1de]  ZMark::mark_and_follow(ZMarkCache*, ZMarkStackEntry)+0x1ee
V  [libjvm.dylib+0x112ab9b]  bool ZMark::drain_and_flush<ZMarkNoTimeout>(ZMarkStripe*, ZMarkThreadLocalStacks*, ZMarkCache*, ZMarkNoTimeout*)+0x5b
V  [libjvm.dylib+0x112aa74]  ZMark::work_without_timeout(ZMarkCache*, ZMarkStripe*, ZMarkThreadLocalStacks*)+0xa4
V  [libjvm.dylib+0x112af02]  ZMark::work(unsigned long long)+0xe2
V  [libjvm.dylib+0x1154bba]  ZTask::GangTask::work(unsigned int)+0x1a
V  [libjvm.dylib+0x110632d]  GangWorker::run_task(WorkData)+0x5d
V  [libjvm.dylib+0x11063ec]  GangWorker::loop()+0x2c
V  [libjvm.dylib+0x1005297]  Thread::call_run()+0x1b7
V  [libjvm.dylib+0xdca75f]  thread_native_entry(Thread*)+0x15f
C  [libsystem_pthread.dylib+0x3661]  _pthread_body+0x154
C  [libsystem_pthread.dylib+0x350d]  _pthread_body+0x0
C  [libsystem_pthread.dylib+0x2bf9]  thread_start+0xd


siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x0000000000000030