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From Christopher Schultz <ch...@christopherschultz.net>
Subject Re: Parallel Classloader - Again
Date Tue, 20 Nov 2018 19:09:27 GMT
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Mark,

On 11/20/18 12:50, Mark Thomas wrote:
> On 20/11/2018 15:21, Andrew Carr wrote:
>> Hello,
>> 
>> We have been seeing some intermittent issues with the parallel 
>> classloader.  I do not want to jump to any conclusions and say
>> this is a bug w/ the classloader, but we are getting deadlocked
>> threads, pretty randomly, when launching the server.  I was
>> wondering if anyone had experienced this issue or if you could
>> review the attached thread dump and give me some feedback.
>> 
>> There is no associated log file for the time the deadlock was 
>> occurring, I am working on getting that.  In unrelated log files
>> I saw some concurrency exceptions, non-thread safe access to
>> lists basically.  I believe that issue has been corrected in the
>> source code, and I am not sure the concurrency exception has
>> anything to do with the deadlock occurring during classloading.
>> 
>> Personally I am of the belief that unsafe maps / lists could
>> possibly cause the classloader to deadlock.
>> 
>> I can put the full dumps in a ticket, I just hate to open
>> another classloader ticket.
> 
> I don't see a deadlock in the provided stack trace.

+1

Summary:

Thread-96:
   - Holds no locks
   - Waiting for lock on 0x0000080048462700

Thread-29
   - Holds locks on 0x0000080048462700, 0x00001000aa2752d8,
0x0000080058b5c5e8
   - Waiting for lock on 0x00001000bbc1dd20

Event Manager Thread_QuartzSchedulerThread:
   - Holds locks on 0x00001000bbc1dd20
   - Not waiting


Maybe there is a part of the thread dump you didn't post?

- -chris
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