Error: Shenandoah assert_correct failed; Object klass pointer must go to metaspace

[Tom van der Woerdt]

Heya,

 

I’m facing a crash when running Apache Cassandra under load, with Shenandoah on the Java 8 backport from RedHat. Also reproducible with the latest builds at https://builds.shipilev.net/openjdk-shenandoah-jdk8/

 

crash.txt, attached, shows the short version of the error. hs_err_pid42292.log has the longer version (from the fastdebug build).

 

I am able to consistently reproduce it in my environment, but it’s not exactly trivial. Steps @ https://gist.github.com/TvdW/0b8b6909c22a537363bb27217a706b1a

 

Some notes:

*	-Xint stops the issue from happening
*	-XX:TieredStopAtLevel=1 seems to make it more likely
*	-XX:+ShenandoahVerify crashes by itself because of the same klass pointer issue

 

Since I’m quite certain this is a Sh bug, I’m sending it directly here; please let me know if there’s anything I can add to help figure this out. This is my first JVM bug so I’m not sure what you need from me ;-)

 

Tom

 

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