RFR: 8316397: StackTrace/Suspended/GetStackTraceSuspendedStressTest.java failed with: SingleStep event is NOT expected [v4]

[Patricio Chilano Mateo]

On Mon, 3 Mar 2025 05:10:52 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Sorry that wasn't well thought out - we would need to pass this through all the mutex code to allow it to be specialized.
>> 
>> Do we still have a "suspension disabler" that would prevent the suspend from being processed by the mutex blocking?
>
> For use in ` JvmtiExport::at_single_stepping_point`.

> Do we still have a "suspension disabler" that would prevent the suspend from being processed by the mutex blocking?
>
We have `JavaThread::_is_disable_suspend` for JVMTI, but that only makes the target ignore the `ThreadSelfSuspensionHandshake` (second part of the suspend mechanism), it doesn't prevent the `SuspendThreadHandshake` (first part) from being executed. The suspender considers the target as suspended after the first handshake is done. (Seems this `_is_disable_suspend` should have prevented the first part instead but I'm guessing it wasn't as straightforward without introducing deadlocks). But also note we have the same issue for other events so we need a general solution.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23490#discussion_r1978435430