RFR: 8308978: regression with a deadlock involving FollowReferences [v2]

[Serguei Spitsyn]

On Wed, 31 May 2023 01:18:12 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

>> The change fixes regression from JDK-8299414.
>> There is a deadlock between JvmtiVTMSTransitionDisabler and EscapeBarrier when virtual threads are in mount/unmount transition:
>> EscapeBarrier requests deoptimization which requires thread suspension.
>> JvmtiVTMSTransitionDisabler ctor waits until all in progress VTMS transitions complete, but they cannot be completed as thread is suspended.
>> To avoid the deadlock mount/unmount transitions should be completed before EscapeBarrier stuff.
>
> Alex Menkov 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 four additional commits since the last revision:
> 
>  - Merge branch 'follow_ref_deadlock' of github.com:alexmenkov/jdk into follow_ref_deadlock
>  - fix
>  - unproblem-list tests
>  - fix

It looks good now.
Thanks,
Serguei

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Marked as reviewed by sspitsyn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/14233#pullrequestreview-1452063742