RFR 8072466: Deadlock when starting MulticastSocket and DatagramSocket

[Chris Hegarty]

This looks like a nice cleanup, and fix. Thanks Ivan.

-Chris.

On 05/09/15 15:25, Ivan Gerasimov wrote:
> Hi everyone!
>
> The fix didn't bring enough attention back in February for some reason.
> So, I'd like to re-request a review.
>
> I've added a regression test, which reliably reproduces a deadlock on my
> local Windows 7 machine.
>
> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8072466
> WEBREV: http://cr.openjdk.java.net/~igerasim/8072466/00/webrev/
>
> Sincerely yours,
> Ivan
>
> On 17.02.2015 9:54, Ivan Gerasimov wrote:
>> Can someone help review this fix please?
>>
>> Comments/suggestions are welcome!
>>
>> Sincerely yours,
>> Ivan
>>
>> On 06.02.2015 20:48, Ivan Gerasimov wrote:
>>> Hello!
>>>
>>> There has been a deadlock in jdk-net code noticed on Windows.
>>>
>>> In the bug description there's a stack snippet showing that one of
>>> the deadlocked threads stuck in the native initialization code of
>>> DualStackPlainDatagramSocketImpl and the other -- in initializing of
>>> TwoStacksPlainDatagramSocketImpl.
>>>
>>> I suspect that the reason might be due to unordered initialization:
>>> AbstractPlainDatagramSocketImpl, the parent of both classes above,
>>> explicitly loads TwoStacksPlainDatagramSocketImpl from the native
>>> init().
>>> Thus, when both classes are being initialized concurrently, it may
>>> end with a clash.
>>>
>>>
>>> Another issue noticed by Mark Sheppard is that the Windows version of
>>> DefaultDatagramSocketImplFactory.createDatagramSocketImpl() isn't
>>> synchronized, but reads/modifies shared data.
>>> Thus, I removed modification and declared all the accessed fields final.
>>>
>>> Would you please help review the proposed fix?
>>>
>>> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8072466
>>> WEBREV: http://cr.openjdk.java.net/~igerasim/8072466/0/webrev/
>>>
>>> The build went fine on all the platforms, all the tests from
>>> (net|nio|io) passed Okay.
>>>
>>> Sincerely yours,
>>> Ivan
>>>
>>>
>>>
>>
>>
>>
>