Sunday, January 25, 2009

Multithreaded CMS crash

I ran across a CMS crash bug in Hotspot 10 b19 (OpenJDK6 b11), which is described here:

http://bugs.sun.com/view_bug.do?bug_id=6722116

The symptom is that VM crashes in the concurrent GC thread at the following stack trace (with mangled symbols):

_ZN24YieldingFlexibleWorkGang10start_taskEP24YieldingFlexibleGangTask
_ZN12CMSCollector13do_marking_mtEb
_ZN12CMSCollector13markFromRootsEb
_ZN12CMSCollector21collect_in_backgroundEb
_ZN25ConcurrentMarkSweepThread3runEv
_Z10java_startP6Thread

A workaround is to use the JVM option -XX:-CMSConcurrentMTEnabled to disable the multithreaded CMS collection. Upgrading to the JDK with newer Hotspot is a better idea, though.

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