JVM hangs beyond recovery

Paul Hohensee paul.hohensee at oracle.com
Tue Jun 8 11:46:38 PDT 2010

The first thing we suspect when we see a hang or memory stomp (your
hang might be caused by a memory stomp) is native code running as part
of the application.  I'd try running your app under a debugger or attach
to it with a debugger or the serviceability agent to get stack traces.  See


for serviceability tools in general.

The switches you mention are


which works around a gc bug.  In some cases there will be a slight gc 
performance loss
using this switch.  It may fix your problem


will disable the fastest path uncontended locking algorithm.  You may or 
may not see
a performance hit by doing so.  Biased locking has been pretty reliable 
for quite awhile,
so it's not too likely that turning it off will fix your problem.


On 6/8/10 2:35 PM, Stas Oskin wrote:
> Hi.
> I encountered the hang in latest jdk1.6.0_20 version.
> I tried to get the threads dump, but both jstack and kill -3 didn't 
> produce any results.
> Below is the GDB dump:
> http://pastie.org/996680
> Earlier in this thread I receive that possible cause is the dlsym 
> function in libdl library. I googled a bit for similar issues, and 
> found only the following potentially similar case:
> http://www-01.ibm.com/support/docview.wss?uid=isg1IZ07615
> I also received advices to:
> * ReduceInitialCardMarks
> or/and
> * UseBiasedLocking
> Which one of them may solve the issue, and what the possible results 
> would be?
> Thanks in advance.

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