why LinkedBlockingQueue#poll(int, TimeUnit) is hanging up?

David Holmes david.holmes at oracle.com
Tue Sep 11 02:05:30 UTC 2012

On 11/09/2012 11:43 AM, Vitaly Davidovich wrote:
> Symptoms here are eerily similar to
> http://bugs.sun.com/view_bug.do?bug_id=6822370, hence I'm curious if it
> still repros with -XX:+UseMembar.

Always an interesting question to ask but 6822370 was fixed in 7 and 
this is reported in 7u5.

We really need a way to reproduce this, and see what all the other 
threads are doing with respect to this queue.


> Sent from my phone
> On Sep 10, 2012 8:45 PM, "David Holmes" <david.holmes at oracle.com
> <mailto:david.holmes at oracle.com>> wrote:
>     This kind of issue is better discussed, at least initially on Doug
>     Lea's concurrency interest list:
>     concurrency-interest at cs.__oswego.edu
>     <mailto:concurrency-interest at cs.oswego.edu>
>     The stack shows that it is the lock acquisition that is blocking
>     indefinitely, not the poll itself. That is why it doesn't time out
>     and why it hangs again immediately after you interrupt the thread.
>     You need to see what is happening to other threads using this LBQ
>     and whether one of them holds the lock and is itself "stuck"
>     somewhere. You also need to see if there are any asynchronous
>     exceptions involved (Thread.stop use, or StackOverflowException) as
>     these can corrupt the internal state of an
>     AbstractQueuedSynchronizer like ReentrantLock.
>     David
>     On 11/09/2012 4:00 AM, Iris Clark wrote:
>         Forwarding to core-libs-dev.
>         iris
>         -----Original Message-----
>         From: Yegor Bugayenko [mailto:egor at technoparkcorp.__com
>         <mailto:egor at technoparkcorp.com>]
>         Sent: Monday, September 10, 2012 5:52 AM
>         To: jdk7-dev at openjdk.java.net <mailto:jdk7-dev at openjdk.java.net>
>         Subject: why LinkedBlockingQueue#poll(int, TimeUnit) is hanging up?
>         I already posted the question here:
>         http://stackoverflow.com/__questions/12349881
>         <http://stackoverflow.com/questions/12349881>
>         Could one of you guys take a look? Thanks!
>         -
>         Yegor

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