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

Sergey Bylokhov Sergey.Bylokhov at oracle.com
Sat Aug 24 22:22:17 UTC 2019


I'll push it soon

On 8/24/19 10:27 am, Phil Race wrote:
> 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.
> 


-- 
Best regards, Sergey.


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