[concurrency-interest] Deadlock with when no threads have the lock

Henri Tremblay henri.tremblay at gmail.com
Sat Jun 17 00:03:49 EDT 2017


If you keep doing thread dumps, is the lock and the waiting threads the
same? So a real deadlock. If yes, Kirk suggestion is interesting. And I
would also do a heap dump to have a look at the threads holding a reference
to the reentrant lock.

On 16 June 2017 at 18:55, Kirk Pepperdine <kirk at kodewerk.com> wrote:

> Hi Ken,
>
> If you have a lock with nothing holding on to it then either a VM thread
> has the lock. The most common culprit are GC threads. I’ve not taken a deep
> look at the code but you could set -XX:+PrintConcurrentLocks which would
> give you an idea if the problem is with the re-enterant lock. Not looked
> too deeply at the code but I don’t see anything obvious at the moment.
>
> — Kirk
>
> On Jun 16, 2017, at 11:36 PM, Ken Sipe <kensipe at gmail.com> wrote:
>
> We have encountered a strange deadlock scenario in which it appears that
> all threads are waiting on acquiring a ReentrantLock, but no thread has the
> lock.
>
> Any thoughts on this?
>
> https://gist.github.com/timcharper/9ab4fea9da4669e620507e85e764d94a
>
>
> Thanks,
> ken
>
>
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