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

[Aleksey Shipilev]

On Mon, 10 Mar 2025 17:27:08 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - Can check <=
>>  - Object handle
>
> 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.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23961#discussion_r1987903694