RFR: 8316401: sun/tools/jhsdb/JStackStressTest.java failed with "InternalError: We should have found a thread that owns the anonymous lock"

[David Holmes]

On Wed, 27 Sep 2023 00:44:30 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> I made a pass over the deadlock detection code involved. Nothing stuck out. There's not much in the way of SA-isms in this code. I think anyone with an understanding of how hotspot locking works should be able to navigate it pretty easily and maybe conjure a hypothesis as to why this happens as frequently as it does.
>
> I wonder if we are in the middle of a GC, the object has been moved, and the lock stack object reference has been updated but the monitor reference has not (or vice versa).

Possible I guess. I added some instrumentation to try and see what threads we have and what their lockstacks show when the failure happens. Of course the test didn't fail after I did that, so having to re-run.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/15907#discussion_r1337987283