8198928: (so) SocketChannel connect may deadlock if closed at around same time that connect fails

[Hamlin Li]

On 06/03/2018 6:04 PM, Alan Bateman wrote:
> On 06/03/2018 08:39, Hamlin Li wrote:
>>
>> Hi Alan,
>>
>> I have minor comment about CloseDuringConnect.java, is it better to 
>> move following code from main() to test()?
>>
>> SocketAddress remote = new InetSocketAddress("127.0.0.1", Utils.getFreePort());
>>
>> It will reduce the chance to interfere with other tests which run 
>> concurrently and also create a listening socket at THE free port same 
>> as this test.
>>
> Good question! There is a general issue with tests that need a free 
> port, or a refusing endpoint in this case. Ideally jtreg would support 
> a per test equivalent of exclusiveAccess.dirs, that way tests can at 
> least reduce interference from tests that execute concurrently without 
> needing to put the test in a special directory.
>
> The issue with Utils.getFreePort in the test infrastructure library is 
> that it sleeps for 100ms. This test results makes 100 attempts to 
> connect to a refusing endpoint so calling getFreePort before each 
> attempt adds significantly to the execution time. Would you have 
> cycles to check into the getFreePort implementation? I suspect the 
> original rational was to handle cases where the system is out of 
> resources but it doesn't catch IOException and sleeps before the first 
> attempt. I didn't want to change it with this patch as it is used by a 
> lot of other tests.
Got it, I can do it.
>
> In the mean-time, maybe we can address your concern by just replacing 
> the use of Utils.getFreePort in this test with its own 
> refusingEndpoint method. I've updated the webrev in place so you can 
> see if you agree. If we get Utils.getFreePort fixed then we can 
> replace this usage, probably other cases like this in other tests too.
For this test, I think another way is to use reserved/unused ports as 
the free port, e.g. port 1, port 4, ... [1]

Thank you
-Hamlin

[1] https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers
>
> -Alan
>
>

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