RFR: 8372652: Re-enable LocalRandom clinit after monitor pinning improvements

[Alan Bateman]

On Tue, 2 Dec 2025 12:48:54 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>>> > Unfortunately, there are might be failure of execution `vmTestbase/`with `JTREG_TEST_THREAD_FACTORY=Virtual`. So it enough ensure the your fix doesn't create new failures and timeouts
>>> 
>>> I am trying to parse this :) So, if `make test TEST=vmTestbase/ JTREG=TEST_THREAD_FACTORY=Virtual` passes, we are good to go, correct?
>> 
>> Sure.
>> I meant that we don't run whole vmTestbase with TEST_THREAD_FACTORY=Virtual, so I am unsure if there are some failures exist now.
>
>> @lmesnik There are failures with `make test TEST=vmTestbase/ JTREG=TEST_THREAD_FACTORY=Virtual` even without the change. 
> 
> Does running with JTREG_EXTRA_PROBLEM_LISTS=ProblemList-Virtual.txt improve this?

> @AlanBateman No, it doesn't help.

I don't have any other suggestions except that this change will likely require a lot of test runs to ensure that it doesn't bring back an issue. My guess (and Leonid might remember more) is that we using a j.u.concurrent lock in the java.io classes was problematic. We reverted this code back to using monitors after JEP 491 was integrated, and as Patricio mentions, a timeout is used to attempt to barge when pinned and this avoids the deadlocks that we might have seen at the time.

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PR Comment: https://git.openjdk.org/jdk/pull/28547#issuecomment-3606459891