Integrated: 8352918: Shenandoah: Verifier does not deactivate barriers as intended

[William Kemper]

On Wed, 26 Mar 2025 19:17:33 GMT, William Kemper <wkemper at openjdk.org> wrote:

> When verifying reachable objects, Shenandoah's verifier clears the `_gc_state` with the intention of deactivating barriers. However, the mechanism for this is a `friend` of the heap and does not toggle the flag to cause threads to use the value set on the verifier's safepoint. The net effect here is that the barriers are _not_ deactivated during verification. Leaving the barriers on while the verifier traverses the heap may have unintended consequences (cards marked, objects evacuated, etc.)

This pull request has now been integrated.

Changeset: 1bd0ce1f
Author:    William Kemper <wkemper at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/1bd0ce1f51760d2e57e94b19b83d3ee0fa4aebcd
Stats:     11 lines in 2 files changed: 7 ins; 0 del; 4 mod

8352918: Shenandoah: Verifier does not deactivate barriers as intended

Reviewed-by: kdnilsen, shade, ysr

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PR: https://git.openjdk.org/jdk/pull/24264