jmx-dev Review Request: 7195779 javax/management/remote/mandatory/threads/ExecutorTest.java fail intermittently

[Jaroslav Bachorik]

On Tue 02 Oct 2012 03:38:13 PM CEST, Alan Bateman wrote:
> On 02/10/2012 09:33, Jaroslav Bachorik wrote:
>> :
>> The generated TIE class is inherently thread-unsafe. The internal state
>> (the target field) can be manipulated without any enforced
>> synchronization - eg. it is valid to set the target field to null by
>> calling the deactivate() method after the _invoke() method has been
>> entered from a different thread. This will lead to the NPE we can
>> observe. Given this example one should make critical sections out of
>> deactivate() and _invoke() methods to prevent this situation. However,
>> this simplistic approach might lead to deadlocks in the existing code
>> as the _invoke() method body might be blocking (it is a 3rd party code)
>> and thus preventing execution of the deactivate() method indefinitely.
>>
>> Also, it is not really possible to solve this problem outside of the
>> generated TIE class - it is caused by the concurrent change of the
>> TIE's internal state. So, the solution would be either caching the
>> target attribute at the beginning of the invoke() operation in a
>> synchronized block and use the cached version afterwards (and throwing
>> a remote exception if it is null - the TIE was deactivated effectively
>> before entering the invoke() operation) or postponing deactivation when
>> the invoke() method is detected as being in progress.
>>
>> -JB-
>>
> Jaroslav and I chatted on IM about this today. Jaroslav is going to
> have a go at changing the stub generator and will send a follow-up
> mail with an updated webrev (this time for the corba repo as the that
> is where the stub generator lives).

This is a follow-up. I've prepared the patch and put it on github - 
https://github.com/jbachorik/openjdk-patches/tree/master/webrevs/7195779

I wonder who else should be included in the review process since I am 
changing the IIOP generator code. Also, I didn't find any tests in the 
corba repository. Which test suite is appropriate to run after changing 
the corba related code?

-JB-


>
> -Alan