Code review request 7132889: Possible race conditions in AbstractSelectableChannel

[Alan Bateman]

On 07/08/2012 10:34, Shirish Kuncolienkar wrote:
> Could I get this change reviewed please
>
> code inspection of the AbstractSelectableChannel class shows that a 
> timing window exists between the channel close and cancellation of the 
> key. Which can lead to following consequences
> 1. Selector registered on this channel can select the key while the 
> channel is closed or is being closed
> 2. A new key can be added to the channel while the it is closed or is 
> being closed
> 3. configureBlocking() can be invoked while the channel is closed or 
> is being closed
>
> One might be able to construct a testcase using a test-specific 
> subclass of AbstractSelectableChannel, which has a synchronization 
> point in its implementation of implCloseSelectableChannel() so that 
> tests can be performed there. However, it would be quite an involved 
> thing to write with clarity.
>
> I have created a patch under http://cr.openjdk.java.net/~luchsh/7132889/
>
The main issue in 7132889 has already been fixed in jdk8 and 7u6 via 
6346658. Would it be possible to test with a build of one of these 
releases and tell us if you still run into the original problem?

On the regLock vs. keyLock issue then I would like to review this but I 
don't have cycles just at the moment as you may be right that the 
synchronization isn't consistent (the synchronization is covered in 
various places in the Selector spec so it requires reading that, 
hopefully I will get time soon but it won't be this week).

-Alan