RFR: 8373944: ObjectMonitor::ExitOnSuspend can call java_lang_VirtualThread::set_onWaitingList() while in safepoint

[Patricio Chilano Mateo]

On Fri, 20 Feb 2026 02:29:42 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Please review the following patch. `ExitOnSuspend::operator()` may run while a safepoint is in progress, which can lead to crashes because releasing the monitor involves touching oops if the successor is a virtual thread. The proposed fix is to process pending operations before releasing the monitor.
>> I added a new test that reliably reproduces the issue with the extra `assert_not_at_safepoint()` added in this patch, and verified the issue is now fixed.
>> 
>> Thanks,
>> Patricio
>
> Fix looks good. Thanks
> 
> Nice test! Five Phasers plus a CountDownLatch - wow!

Thanks for the reviews @dholmes-ora and @fbredber!

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PR Comment: https://git.openjdk.org/jdk/pull/29822#issuecomment-3945663943