RFR: 8316746: Top of lock-stack does not match the unlocked object [v3]

[Martin Doerr]

On Thu, 28 Sep 2023 10:38:52 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

>> I think we need to support "Top of lock-stack does not match the unlocked object" and take the slow path. Reason: see JBS issue.
>> Currently only PPC64, x86_64 and aarch64 code. I'd like to get feedback before implementing it for other platforms (needed for all platforms).
>
> Martin Doerr 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:
> 
>  - Pass may_be_unordered information to lightweight_unlock.
>  - Merge remote-tracking branch 'origin' into 8316746_lock_stack
>  - Add x86_64 and aarch64 implementation.
>  - 8316746: Top of lock-stack does not match the unlocked object

I have an other interesting experiment:
`make run-test TEST="vmTestbase/nsk/jdi/StepEvent" JTREG="VM_OPTIONS=-Xbatch"` reproduces the issue most of the time on PPC64.
However, `make run-test TEST="vmTestbase/nsk/jdi/StepEvent" JTREG="VM_OPTIONS=-Xbatch -XX:AsyncDeflationInterval=0"` appears to run stable.
Not sure if that's a coincidence or if the async deflation messes something up.

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PR Comment: https://git.openjdk.org/jdk/pull/15903#issuecomment-1761602707