RFR: 8351045: ClassValue::remove cannot ensure computation observes up-to-date state [v2]

[Roger Riggs]

On Wed, 5 Mar 2025 15:19:27 GMT, Chen Liang <liach at openjdk.org> wrote:

>> After a call to `ClassValue.remove`, a `ClassValue` can still install a value that is computed with information that is not up-to-date with the remove call. This is demonstrated in the test case, where an innocuous `ClassValue.get` call on an uncomputed CV may happen to compute during which a remove happened, and proceed to install an outdated value onto a CV.
>> 
>> The fix is simple - to force computation to retry when a remove has happened, so the retry can observe the up-to-date states from the remove. (finishEntry and removeEntry are both synchronized on the object monitor of the ClassValueMap instance)
>
> Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Improve docs
>  - Merge branch 'master' of https://github.com/openjdk/jdk into fix/classvalue-remove
>  - 8351045: ClassValue::remove cannot ensure computation observes up-to-date state

Marked as reviewed by rriggs (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/23866#pullrequestreview-2675920565