RFR 8171971: Fix timing bug in JVM management of package export lists

[harold seigel]

Hi Alan,

 >> I hope it can be looked at again to make it lock-free some day.

We plan to do this as part of JDK-10.

Thanks, Harold

On 1/18/2017 10:48 AM, Alan Bateman wrote:
>
>
> On 18/01/2017 15:46, harold seigel wrote:
>> Hi Alan,
>>
>> The VM was already lockng the Module_lock during an access check when 
>> doing a qualified exports check.  This change expands the scope of 
>> the of that lock to also cover checking if the packing is 
>> unqualifiedly exported.
> I hope it can be looked at again to make it lock-free some day.
>
>>
>> Can JVMTI be used to change a package's export state from qualified 
>> to unqualified?
> No, qualified exports and opens only.
>
> -Alan