Integrated: 8350649: Class unloading accesses/resurrects dead Java mirror after JDK-8346567

[Aleksey Shipilev]

On Tue, 25 Feb 2025 13:00:52 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> See bug for description of the bug. Shenandoah seems to be the only GC that runs into this problem so far.
> 
> Before [JDK-8346567](https://bugs.openjdk.org/browse/JDK-8346567), we pulled class modifiers from the native `Klass*`, and so we bypassed this trouble. But now we take modifiers out of Java mirror, and this happens during unloading, which accesses/resurrects potentially dead mirror.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, original reproducer now passes
>  - [x] Linux x86_64 server fastdebug, `hotspot_gc_shenandoah`
>  - [x] Linux x86_64 server fastdebug, `jdk_jfr`
>  - [x] Linux x86_64 server fastdebug, `jdk_jfr` with `-XX:+UseShenandoahGC` now passes

This pull request has now been integrated.

Changeset: ec6624b5
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/ec6624b54eaf5c0f94bd760d2e9fa8b55717c350
Stats:     7 lines in 2 files changed: 5 ins; 0 del; 2 mod

8350649: Class unloading accesses/resurrects dead Java mirror after JDK-8346567

Reviewed-by: coleenp, egahlin

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PR: https://git.openjdk.org/jdk/pull/23775