[OpenJDK 2D-Dev] RFR: 8263138: Initialization of sun.font.SunFontManager.platformFontMap is not thread safe

Andrey Turbanov github.com+741251+turbanoff at openjdk.java.net
Sun Mar 7 19:36:16 UTC 2021


On Sun, 28 Feb 2021 04:56:07 GMT, Sergey Bylokhov <serb at openjdk.org> wrote:

>> https://github.com/openjdk/jdk/pull/2691#issuecomment-784367127
>> 
>> In short, previously platformFontMap references were field set/gets and may be inconsistent due to concurrency. It is now moved to a local variable; also the map modifications have been moved to fields to avoid concurrency issues with hash map as far as I can see.
>
> One thread may create the local platformFontMap, then set the static SunFontManager.platformFontMap field, and then initialize the platformFontMap or mix these operations. The second thread may see non-null SunFontManager.platformFontMap which is not still initialized.

Made `volatile` to guarantee memory visibility if thread saw non-null value.

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PR: https://git.openjdk.java.net/jdk/pull/2762


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