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SIGSEGV in ConcurrentGCThread using 6u14's new "Garbage First" collector

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nielsmayer
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Joined: 2009-02-19
Points: 0

( pasted from http://nielsmayer.com/xwiki/bin/view/fedora10/64bitJavaAppletIn64BitFire... note the comment applies to jre6u14 running Tomcat and some webapps on a live server )

For info on 6u14's new GC and potential usefulness for use with java web
apps, see:
http://n2.nabble.com/Does-JDK6u14-%22Garbage-First-garbage-collector-%28...
http://n2.nabble.com/forum/PrintPost.jtp?post=2344358 (cancel the print dialog: this gives you the complete message w/o extra crap).

Unfortunately, when running with

>VM Arguments:
>jvm_args: -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -Xms256m -Xmx768m -XX:PermSize=256m -XX:MaxPermSize=768m -Djava.awt.headless=true >...
>java_command: org.apache.catalina.startup.Bootstrap start

You get a SIGSEGV (which obviates the whole point of garbage-collection):

>A fatal error has been detected by the Java Runtime Environment:
>SIGSEGV (0xb) at pc=0x0000000000e9c621, pid=13441, tid=114968912
>JRE version: 6.0_14-b01
>Java VM: OpenJDK 64-Bit Server VM (14.0-b10 mixed mode linux-amd64 )
>Problematic frame:
>V [libjvm.so+0x296621]

The SIGSEGV happens because of new Garbage Collector, as invoked by
"-XX:+UnlockExperimentalVMOptions -XX:+UseG1GC". It dies after running for
less than an hour:

>Current thread (0x000000004149f000): ConcurrentGCThread [stack: 0x0000000000000000,0x0000000000000000] [id=13448]
>siginfo:si_signo=SIGSEGV: si_errno=0, si_code=1 (SEGV_MAPERR), si_addr=0x0000001600000050
>...
>elapsed time: 2916 seconds

This issue doesn't occur with the default GC invoked with

>jvm_args: -Xms256m -Xmx768m -XX:PermSize=256m -XX:MaxPermSize=768m -Djava.awt.headless=true"

I guess that's why this is an "Early Access" release.

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linuxhippy
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Joined: 2004-01-07
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Well, seems like a bug.

Best is probably to report the problem to http://java.sun.com/webapps/bugreport/crash.jsp , so that guys can fix it.

- Clemens

nielsmayer
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Joined: 2009-02-19
Points: 0

I tried, and the bugreporting website failed to notify that the bug was received. It did do something glitchy after final submit... Is there a record of my bug submitted? I believe I tried twice, with a browser restart for good measure. I had all the goodies attached and everything. Now I'm not sure where they even are anymore... I just wrote this comment and moved on: http://nielsmayer.com/xwiki/bin/view/fedora10/64bitJavaAppletIn64BitFire...

rogyeu
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Joined: 2006-07-30
Points: 0

I can't find it in our bug reporting system DB. Could you please submit another one? You can post the incident number and I'll post back the bug ID after I've verified the issue. Also, it'll be easier for me to find your bug report if you can provide your Sun Online Account ID during your bug submission process.