JVM hanging when using G1GC on JDK8 b78 or b79 (Linux 32 bit)

Uwe Schindler uschindler at apache.org
Wed Mar 6 02:12:09 PST 2013

Thanks, I'll try to use jstack with -F or -m!


Uwe Schindler
uschindler at apache.org 
Apache Lucene PMC Member / Committer
Bremen, Germany

> -----Original Message-----
> From: Krystal Mok [mailto:rednaxelafx at gmail.com]
> Sent: Wednesday, March 06, 2013 7:08 AM
> To: Uwe Schindler
> Cc: hotspot-gc-dev at openjdk.java.net; hotspot-dev at openjdk.java.net;
> Dawid Weiss; dev at lucene.apache.org
> Subject: Re: JVM hanging when using G1GC on JDK8 b78 or b79 (Linux 32 bit)
> Hi Uwe,
> If you can attach gdb onto it, and jstack -m and jstack -F should also work;
> that'll get you the Java stack trace.
> (But it probably doesn't matter in this case, because the hang is probably bug
> in the VM).
> - Kris
> On Wed, Mar 6, 2013 at 5:48 AM, Uwe Schindler <uschindler at apache.org>
> wrote:
> > Hi,
> >
> > since a few month we are extensively testing various preview builds of JDK
> 8 for compatibility with Apache Lucene and Solr, so we can find any bugs
> early and prevent the problems we had with the release of Java 7 two years
> ago. Currently we have a Linux (Ubuntu 64bit) Jenkins machine that has
> various JDKs (JDK 6, JDK 7, JDK 8 snapshot, IBM J9, older JRockit) installed,
> choosing a different one with different hotspot and garbage collector
> settings on every run of the test suite (which takes approx. 30-45 minutes).
> >
> > JDK 8 b79 works so far very well on Linux, we found some strange behavior
> in early versions (maybe compiler errors), but no longer at the moment.
> There is one configuration that constantly and reproducibly hangs in one
> module that is tested: The configuration uses JDK 8 b79 (same for b78), 32
> bit, and G1GC (server or client does not matter). The JVM running the tests
> hangs irresponsible (jstack or kill -3 have no effect/cannot connect, standard
> kill does not stop it, only kill -9 actually kills it). It can be reproduced in this
> Lucene module 100% (it hangs always).
> >
> > I was able to connect with GDB to the JVM and get a stack trace on all
> threads (see attachment, dump.txt). As you see all threads of G1GC seem to
> hang in a syscall (os:park(), a conditional wait in pthread library).
> Unfortunately that’s all I can give you. A Java stacktrace is not possible
> because the JVM reacts on neither kill -3 nor jstack. With all other garbage
> collectors it passes the test without hangs in a few seconds, with 32 bit G1GC
> it can stand still for hours. The 64 bit JVM passes with G1GC, so only the 32 bit
> variant is affected. Client or Server VM makes no difference.
> >
> > To reproduce:
> > - Use a 32 bit JDK 8 b78 or b79 (tested on Linux 64 bit, but this
> > should not matter)
> > - Download Lucene Source code (e.g. the snapshot version we were
> > testing with:
> > https://builds.apache.org/job/Lucene-Artifacts-trunk/2212/artifact/luc
> > ene/dist/)
> > - change to directory lucene/analysis/uima and run:
> >         ant -Dargs="-server -XX:+UseG1GC" -Dtests.multiplier=3
> > -Dtests.jvms=1 test After a while the test framework prints "stalled"
> messages (because the child VM actually running the test no longer
> responds). The PID is also printed. Try to get a stack trace or kill it, no
> response. Only kill -9 helps. Choosing another garbage collector in the above
> command line makes the test finish after a few seconds, e.g. -Dargs="-server
> -XX:+UseConcMarkSweepGC"
> >
> > I posted this bug report directly to the mailing list, because with earlier bug
> reports, there seem to be a problem with bugs.sun.com - there is no
> response from any reviewer after several weeks and we were able to help to
> find and fix javadoc and javac-compiler bugs early. So I hope you can help for
> this bug, too.
> >
> > Uwe
> >
> > -----
> > Uwe Schindler
> > uschindler at apache.org
> > Apache Lucene PMC Member / Committer
> > Bremen, Germany
> > http://lucene.apache.org/
> >
> >
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