[jdk21u-dev] RFR: 8331735: UpcallLinker::on_exit races with GC when copying frame anchor

[Goetz Lindenmaier]

On Thu, 20 Feb 2025 16:23:03 GMT, Andrew John Hughes <andrew at openjdk.org> wrote:

> Clean backport of a fix for a race condition in code adapted from `JavaCallWrapper` for the FFM API. This is more visible in 22 and later, where FFM is fully supported and the [OpenType implementation using HarfBuzz](https://bugs.openjdk.org/browse/JDK-8318364) has been ported to use it. However, the copy in the native state seems to have been introduced as far back as [JDK-8269240](https://bugs.openjdk.org/browse/JDK-8269240) in 17 when the `JavaCallWrapper` code was ported to what was then `universalUpcallHandler.cpp`.

@gnu-andrew, you might want to push this, today 18:00 CET the last automatic merge from jdk21u-dev to jdk21u will happen.

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PR Comment: https://git.openjdk.org/jdk21u-dev/pull/1424#issuecomment-2682081349