RFR: 8372566: Genshen: crash at ShenandoahScanRemembered::process_clusters after JDK-8371667

[Y. Srinivas Ramakrishna]

On Thu, 27 Nov 2025 03:10:18 GMT, Xiaolong Peng <xpeng at openjdk.org> wrote:

> For non-plab allocs in old gen, the objects need to be registered in card table, which was missed in the [PR](https://git.openjdk.org/jdk/pull/28247) for JDK-8371667. The bug didn't cause jtreg test failures in GHA and my local test, but when I ran specjbb benchmarks, it did cause crash at ShenandoahScanRemembered::process_clusters when GC scans remembered set. 
> 
> The bug may cause other issue since the object in old gen is not properly registered, e.g. marking phase have wrong result.
> 
> Tests:
> - [x]  specjbb, no crash
> - [x] hotspot_gc_shenandoah

Marked as reviewed by ysr (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/28521#pullrequestreview-3525935185