RFR: 8290043: serviceability/attach/ConcAttachTest.java failed "guarantee(!CheckJNICalls) failed: Attached JNI thread exited without being detached"

[David Holmes]

On Mon, 6 Jan 2025 09:33:31 GMT, David Holmes <dholmes at openjdk.org> wrote:

> This bug was introduced by [JDK-8252921](https://bugs.openjdk.org/browse/JDK-8252921) which moved the unregister call from the thread destructor (because it was not called for all threads) to the post_run() method. But this totally overlooked native threads that attach and detach! This is easily fixed by moving the unregister call to the end of JavaThread::exit.
> 
> We also update the ProblemList and disable -Xcheck:JNI for a test that does actually terminate threads without detaching.
> 
> Testing: tiers 1-4
> 
> Thanks.

Okay I've taken a different tack here as I've discovered additional problems. See the description for an updated analysis of the problem and the chosen fix.

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PR Comment: https://git.openjdk.org/jdk/pull/22924#issuecomment-2581567268