RFR: 8351484: Race condition in max stats in MonitorList::add [v2]

[Patricio Chilano Mateo]

On Mon, 10 Mar 2025 19:33:14 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> test/hotspot/gtest/runtime/test_synchronizer.cpp line 81:
>> 
>>> 79: 
>>> 80:   // Something to reference in OM. It makes no difference which oop it is,
>>> 81:   // as long as it is correct.
>> 
>> Can’t we still safepoint on `workers.doit()` when calling `VMThreadBlocker::start()`? Maybe we could use a Handle to be safe. Sidenote: This is pre-existent but isn’t `TestThreadGroup::doit()` missing a call to `_blocker->ready()` before starting the worker threads?
>
> Right, I copy-pasted oop allocation from another test, but forgot to copy-paste the oop handle. Fixed now.
> 
> For `TestThreadGroup::doit()`, yeah, looks like `_blocker->ready()` is missing. It looks innocuous to this test, but we should really fix it, perhaps separately.

Thanks, filed JDK-8351599 for that.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23961#discussion_r1988054564