JDK11 + ZGC JVM Crash

Charlie Hunt charlie.hunt at oracle.com
Fri Jul 9 19:55:06 UTC 2021

Hi Roy,

Thanks for the feedback on running ZGC in JDK 11.

Just to remind you that ZGC is an experimental feature in JDK 11.

ZGC became non-experimental in JDK 15.

What this means is ... if you are experiencing an issue with ZGC in JDK 11 thru JDK 14 where ZGC was an experimental feature, the appropriate resolution would be to migrate to one of; [ideally] the most recent JDK 15 update release, or [ideally] the most recent JDK 16 update release.

There were a very large number of improvements in ZGC between JDK 11 ZGC and JDK 15 ZGC, and likewise JDK 16.

If you experience an issue with ZGC in either JDK 15 or JDK 16, please let us know.


Charlie Hunt

From: zgc-dev <zgc-dev-retn at openjdk.java.net> on behalf of Roy Zhang <roy.sunny.zhang007 at gmail.com>
Sent: Wednesday, July 7, 2021 7:12 AM
To: zgc-dev at openjdk.java.net <zgc-dev at openjdk.java.net>
Subject: JDK11 + ZGC JVM Crash

Dear ZGC Experts,

In our 32G heap Kafka server, our JVM crashed twice, is it due to known ZGC
issues? Thanks in advance!
JDK version: OpenJDK 64-Bit Server VM Corretto-

Excerpt of JVM Crash log:

# A fatal error has been detected by the Java Runtime Environment:
#  SIGSEGV (0xb) at pc=0x00007ffa5b7ea200, pid=4649, tid=4951
# JRE version: OpenJDK Runtime Environment Corretto- (11.0.10+9)
(build 11.0.10+9-LTS)
# Java VM: OpenJDK 64-Bit Server VM Corretto- (11.0.10+9-LTS,
mixed mode, tiered, z gc, linux-amd64)
# Problematic frame:
# V  [libjvm.so+0xf14200]  ZPage::relocate_object_inner(unsigned long,
unsigned long)+0x90
# No core dump will be written. Core dumps have been disabled. To enable
core dumping, try "ulimit -c unlimited" before starting Java again
# If you would like to submit a bug report, please visit:
#   https://github.com/corretto/corretto-11/issues/

---------------  S U M M A R Y ------------

Command Line: -Xmx32G -Xms32G -XX:+UnlockExperimentalVMOptions -XX:+UseZGC
-Dcom.sun.management.jmxremote.ssl=false -Djava.net.preferIPv4Stack=tr
kafka.Kafka /server/kafka-2.1.1/config/server.properties

Host: Intel(R) Xeon(R) Platinum 8252C CPU @ 3.80GHz, 48 cores, 184G, Amazon
Linux release 2 (Karoo)
Time: Fri Jun 18 03:21:39 2021 UTC elapsed time: 9338153.258651 seconds
(108d 1h 55m 53s)

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

Current thread (0x00007ffa54074ff0):  GCTaskThread "ZWorker#23" [stack:
0x00007ffa3c084000,0x00007ffa3c184000] [id=4951]

Stack: [0x00007ffa3c084000,0x00007ffa3c184000],  sp=0x00007ffa3c182bc0,
 free space=1018k
Native frames: (J=compiled Java code, A=aot compiled Java code,
j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0xf14200]  ZPage::relocate_object_inner(unsigned long,
unsigned long)+0x90
V  [libjvm.so+0xf1465e]  ZPage::relocate_object(unsigned long)+0x3e
V  [libjvm.so+0xf04ac7]  ZHeap::relocate_object(unsigned long)+0x77
V  [libjvm.so+0xef0c5a]  ZRelocateRootOopClosure::do_oop(oopDesc**)+0x6a
V  [libjvm.so+0xf0f066]  ZNMethodTable::oops_do(OopClosure*)+0x116
V  [libjvm.so+0xf1c97a]  ZRootsIterator::oops_do(OopClosure*, bool)+0x43a
V  [libjvm.so+0xf1aa15]  ZRelocateRootsTask::work()+0x25
V  [libjvm.so+0xf2679c]  ZTask::GangTask::work(unsigned int)+0x1c
V  [libjvm.so+0xee7b83]  GangWorker::loop()+0x43
V  [libjvm.so+0xe502dd]  Thread::call_run()+0x14d
V  [libjvm.so+0xc0469c]  thread_native_entry(Thread*)+0xec


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