RFR: 8366659: ObjectMonitor::wait() can deadlock with a suspension request [v4]

[Anton Artemov]

On Mon, 10 Nov 2025 19:53:09 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:

>> Anton Artemov has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 18 commits:
>> 
>>  - Merge remote-tracking branch 'origin/master' into JDK-8366659-OM-wait-suspend-deadlock
>>  - 8366659: Added a comment to a boolean arg for enter()
>>  - Merge remote-tracking branch 'origin/master' into JDK-8366659-OM-wait-suspend-deadlock
>>  - Merge remote-tracking branch 'origin/master' into JDK-8366659-OM-wait-suspend-deadlock
>>  - 8366659: Fixed new lines.
>>  - Merge remote-tracking branch 'origin/master' into JDK-8366659-OM-wait-suspend-deadlock
>>  - 8366659: Removed incorrect assert,
>>  - 8366659: Fixed merge conflict
>>  - 8366659: Fixed whitespace.
>>  - 8366659: Disabled posting JVMTI events in reenter-etner path of wait. Postponed waited event.
>>  - ... and 8 more: https://git.openjdk.org/jdk/compare/79fee607...31482ba4
>
> src/hotspot/share/runtime/objectMonitor.cpp line 533:
> 
>> 531: }
>> 532: 
>> 533: void ObjectMonitor::enter_with_contention_mark(JavaThread* current, ObjectMonitorContentionMark &cm, bool post_jvmti_events) {
> 
> In the baseline also: `cm` is passed in, but it only used for this:
> `assert(cm._monitor == this, "must be");`.
> 
> This makes me wonder if we're missing some code in `enter_with_contention_mark`
> that is normally done when we are passed an `ObjectMonitorContentionMark`.

Yes, in `enter_with_contention_mark` the mark itself is only for assertion. I agree that is not clear, if there is any issue popping up, we can address it in a separate PR.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27040#discussion_r2514088683