<AWT Dev> [8u/9] Review request: JDK-8028486 [TEST_BUG] [macosx] java/awt/Window/WindowsLeak/WindowsLeak.java fails

Anton Tarasov anton.tarasov at jetbrains.com
Fri Apr 29 12:53:09 UTC 2016

Thanks for the quick look.

> On 29 Apr 2016, at 15:22, Sergey Bylokhov <Sergey.Bylokhov at oracle.com> wrote:
> Hi, Anton.
> It seems that the surface data will be leaked anyway?

It seems so. But that might be not that critical, because it doesn’t hold (it won’t) any UI controls and all the UI tree. Anyway it leaks, yes.

> Assigned the peer/surfaceData to null in CGLayer can causes an NPE in all its usage, because there is no any synchronization which will prevent the usage of CGLayer after disposing.

That’s bad. Will wrapping the refs with AtomicReference help?

> Unrelated to the fix, but it seems we should call flush() on surface when the layer is disposed, at least I do not understand where we flush the native ogl data for the latest surface data.

This will trigger CGLLayerSurfaceData.invalidate(), but the “layer” will still not be nullified. What about nullifying it in invalidate()? Will we face the same synchronisation issue?


> On 29.04.16 15:00, Anton Tarasov wrote:
>> Hi Sergey, Alexander,
>> Please review the fix:
>> bug: JDK-8028486 [TEST_BUG] [macosx] java/awt/Window/WindowsLeak/WindowsLeak.java fails
>> webrev: http://cr.openjdk.java.net/~ant/JDK-8028486/webrev.0
>> I’m copying my comment from CR:
>> Please open the attached screenshot [*], made with YourKit, where a chain of links is shown from the GC roots.
>> The frame is held by its peer which is held by CGLLayer which is held as validatedSrcData in the GL context.
>> The point is that the GL context doesn't cleanup the last state until under some conditions, which are not applicable to this scenario.
>> I'm not sure should the cleanup be triggered here or not, but the problem can be solved otherwise.
>> The point is that in the chain the CGLLayer instance has been disposed, in response to the frame disposal.
>> So, this is the only ref that holds it (the JNI ref is released by the native peer on disposal).
>> Thus, as the layer is disposed it can at least zero all the java refs it holds (this change already fixes the problem).
>> Then, the "layer" ref in CGLLayerSurfaceData should probably be made weak.
>> [*] https://bugs.openjdk.java.net/secure/attachment/59121/8028486.png
>> As to the “weak ref” mentioned in the comment. I didn’t do that, but if you find it reasonable I can add that change (or file a separate CR).
>> Also, the fix contains some additional cleanup (not related to this CR): two more JNI local refs leak, fixed.
>> Thanks,
>> Anton.
> -- 
> Best regards, Sergey.

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