[OpenJDK 2D-Dev] bug 8146238 - Java Queue Flusher on MacOS

[Phil Race]

Sergey,

Since you proposed this version of the fix, do you want to push it ?

-phil.


On 8/24/19 5:09 AM, Alexey Ushakov wrote:
> Hi Sergey,
>
> The proposed solution looks good for me.
>
> Best Regards,
> Alexey
>
>
>> On 12 Aug 2019, at 12:29, Sergey Bylokhov <Sergey.Bylokhov at oracle.com> wrote:
>>
>> Hi, Phil, Alexey.
>>
>> I recheck this bug, and here is some of my thought:
>> 1. We have two java classes:
>>     - GLX/CGL/WGL/GraphicsConfig which maintain the native structure WGL/GLX/CGL/GraphicsConfigInfo
>>     - GLX/CGL/WGL/SurfaceData which maintain the native structure CGL/GLXS/WGL/SDOps
>> 2. The native structures should be disposed of by the "Disposer" machinery
>> 3. The native part XXXSDOps has a pointer to the CGL/GraphicsConfigInfo
>> 4. To prevent the usage of dangling pointer to the XXXGraphicsConfigInfo, the java part of XXXSDOps has a strong reference to the java part of XXXGraphicsConfigInfo
>>
>> The assumption at point 4 is not correct, it is possible that the native part of the XXXGraphicsConfigInfo could be disposed before XXXSDOps, and we will get a crash when we will try to dispose the XXXSDOps.
>>
>> Long time ago when it was implemented it works fine, because we never dispose the graphics configs, we read them on-start and use till the end of the application, even now we use this approach on Linux(JDK-8076313).
>>
>> So this bug existed on Linux, Windows and migrated to the macOS platform, but only on macOS and windows we can get a crash.
>>
>>
>> I have rechecked the usage of the pointer from XXXSDOps to XXXGraphicsConfigInfo which caused a crash and think that we can get rid it, but it will required to change bunch of code on all platforms, so as a minimal fix I suggest this one:
>> http://cr.openjdk.java.net/~serb/8146238/webrev.00
>> Just to store the reference to the GC till the moment it will not be used by the SurfaceData.
>>
>>
>> On 8/7/19 10:56 am, Phil Race wrote:
>>> Sergey,
>>> This fix seems OK to me. Can you please do whatever re-evaluation you meant
>>> as I'd like to pull it into jdk/client for Alexey (since he does not have current commit rights).
>>> -phil.
>>> On 3/8/18 2:59 PM, Sergey Bylokhov wrote:
>>>> Hi, Bill.
>>>> Thank you for confirmation.
>>>>
>>>> On 08/03/2018 14:08, Bill York wrote:
>>>>> 3. Is there a plan to get this bug fix into the JRE distributed by Oracle?
>>>> I will reevaluate the fix for inclusion in jdk11.
>>>>
>>>>
>>
>> -- 
>> Best regards, Sergey.