[jdk17u-dev] RFR: 8334482: Shenandoah: Deadlock when safepoint is pending during nmethods iteration

[Paul Hohensee]

On Tue, 30 Jul 2024 13:27:53 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Fixes Shenandoah deadlock. There are few minor differences that make the backport unclean: 
>  - the absence of [JDK-8273559](https://bugs.openjdk.org/browse/JDK-8273559) that added another argument to GC in JDK 18
>  - the existence of `ShenandoahNMethodPurgeTask` that was removed along with Sweeper with [JDK-8290025](https://bugs.openjdk.org/browse/JDK-8290025) in JDK 20
>  - the existence of `ICStubVerifier` that was removed in JDK 23 with [JDK-8322630](https://bugs.openjdk.org/browse/JDK-8322630)
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, `all` with `-XX:+UseShenandoahGC`
>  - [x] Linux AArch64 server fastdebug, `all` with `-XX:+UseShenandoahGC`

Marked as reviewed by phh (Reviewer).

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PR Review: https://git.openjdk.org/jdk17u-dev/pull/2751#pullrequestreview-2210848207