RFR [8034262] Test java/lang/ProcessBuilder/CloseRace.java fails

[Martin Buchholz]

Well done!

Not checking for interrupt in the loop is clearly my bug.

dumpAllStacks looks like a very useful utility method (basically what
jstack does).  It feels like we're reinventing the wheel here, but I'm not
sure.

Instead of "break theLoop" I would have simply returned from the method.


On Tue, Mar 11, 2014 at 11:03 AM, Ivan Gerasimov
<ivan.gerasimov at oracle.com>wrote:

>  Thank you Martin!
>
>
> On 11.03.2014 19:04, Martin Buchholz wrote:
>
> Thanks for working on my brittle racy tests.
>
>  Adding a latch as you did is a good improvement, although there's a good
> chance the real problem lies elsewhere.
>
>  My standard name for such latches is "threadsStarted", which I think is
> a bit better than "startedSignal".  Please rename.
>
>   No problem, renamed.
>
>
>  My simple calls to Thread.join are too optimistic.
> More likely to be helpful is code like (pseudocode follows):
>
>  thread.join(10, SECONDS);
> if (thread.isAlive()) {
>   dumpAllStacks();
>    fail();
> }
>
>   Yes, it was a good idea to do that!
> After implementing your suggestion, I could finally reproduce the failure.
> The OpenLoop child thread was spinning in the do-while loop, waiting for
> 'count of fds in use' to become 3.
> The simple solution is to add a check weather the current thread is
> interrupted to this and other loops.
>
> Would you please take a look at the updated webrev?
> http://cr.openjdk.java.net/~igerasim/8034262/1/webrev/
>
> Sincerely yours,
> Ivan
>
>
>  That's  more work to implement - optional.
>
>
> On Tue, Mar 11, 2014 at 5:24 AM, Ivan Gerasimov <ivan.gerasimov at oracle.com
> > wrote:
>
>> Hello everybody!
>>
>> The test java/lang/ProcessBuilder/CloseRace.java was reported to
>> intermittently fail.
>> The test timed out, which should mean that at least one of the child
>> threads was never interrupted.
>>
>> I couldn't reproduce the failure, but I suspect it might happen due to
>> call to interrupt() before the child thread became alive (I'm not really
>> sure if it's possible to be non-alive after call to start()).
>> The fix is to explicitly synchronize children with the parent.
>>
>> Would you please help review the fix?
>>
>> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8034262
>> WEBREV: http://cr.openjdk.java.net/~igerasim/8034262/0/webrev/
>>
>> Sincerely yours,
>> Ivan
>>
>
>
>