RFR 7122142 : (ann) Race condition between isAnnotationPresent and getAnnotations

[Peter Levart]

Helo,

I need a Reviewer for the following patch:

http://cr.openjdk.java.net/~plevart/jdk8-tl/AnnotationType/webrev.05/

This fixes deadlock situation described in bug:

     http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7122142

The in-depth evaluation of the patch is described in the introductory 
message of this thread:

http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-June/018226.html

The above is the 5th revision of the patch that also makes sure a single 
AnnotationType instance is ever returned for the same Class object even 
when multiple threads concurrently request one.


Regards, Peter

On 07/05/2013 04:04 PM, Joel Borggrén-Franck wrote:
> Hi Peter,
>
> Thanks for the quick update!
>
> While I have looked over the changes to j.l.Class and the cas in AnnotationType I don't think I'm qualified to review that. (FWIW it looked fine to me but my jmm isn't swapped in at the moment so I won't pretend to know the interactions between volatile and Unsafe cas). Thinking out loud I suppose we can assume a stable offset of fields in Class, and I realize that part has been under review before.
>
> The rest of AnnotationType, AnnotationParser and the tests look fine though. I also ran the tests before and after the change and results were as expected.
>
> Since I'm not a Reviewer kind of reviewer you need to get one those to sign off but after that I think you are good to go. I can sponsor this as well if Alan is busy.
>
> cheers
> /Joel
>
> On 5 jul 2013, at 11:12, Peter Levart <peter.levart at gmail.com> wrote:
>
>> Hi Again,
>>
>> Sorry, the 4th revision I posted is not rebased to the current tip of jdk8-tl so it contained some diffs that reverted some things.
>>
>> Here's the correct patch:
>>
>> http://cr.openjdk.java.net/~plevart/jdk8-tl/AnnotationType/webrev.05/
>>
>>
>> Regards, Peter
>>
>>
>> On 07/05/2013 10:32 AM, Peter Levart wrote:
>>> Hi Joel,
>>>
>>> Here's the 4th revision of the patch:
>>>
>>> http://cr.openjdk.java.net/~plevart/jdk8-tl/AnnotationType/webrev.04/
>>>
>>> This one introduces CAS-ing of the AnnotationType instance into the Class.annotationType field so that there's only a single instance ever returned for a single Class. I also introduced new private static Class.Atomic nested class that is used to lazily initialize Unsafe machinery and to provide a safe wrapper for internal j.l.Class use. Previously this was part of ReflectionData nested class because it was only used for it's purpose. In anticipation to have a need for more atomic operations in the future, I moved this code to a separate class. ReflectionData is now just a record.
>>>
>>> Regards, Peter