RFR: 8324881: ObjectSynchronizer::inflate(Thread* current...) is invoked for non-current thread [v4]

[Axel Boldt-Christmas]

On Thu, 1 Feb 2024 09:38:27 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> The `ObjectSynchronizer` has always assumed that the `current` parameters are both the current thread as well as the thread that is doing the locking. The only time that we are entering on behalf of another thread is when doing re-locking in deoptimization. This has worked because the deoptee thread is suspended. However ResourceMarks have been using the wrong thread when logging is enabled.
>> 
>> This change `ObjectSynchronizer` instruments the relevant methods with both a `JavaThread* locking_thread` as well as `[Java]Thread* current` to be able to use the correct thread for ResourceMarks. 
>> 
>> Having the `inflate` care about a `locking_thread` is a little unpleasant in my opinion. But it is required for LM_LIGHTWEIGHT. 
>> Would probably be cleaner if the inflate for LM_LIGHTWEIGHT was it's own thing, as it does not share the whole INFLATING protocol. But seems like a future RFE to refactor this code.
>> 
>> Can reproduce a crash by modifying `test/jdk/com/sun/jdi/EATests.java` and using `-XX:DiagnoseSyncOnValueBasedClasses=2` with LM_LEGACY or running `test/jdk/com/sun/jdi/EATests.java` with LM_LIGHTWEIGHT/LM_MONITOR and `-Xlog:monitorinflation=trace`. 
>> 
>> Could extend this test to capture this regression in the future (or creating a new test based on the same infrastructure). Will give it an attempt, so we have a regression test for this. But these tests get rather involved as the require a lot of jvmti setup.
>
> Axel Boldt-Christmas has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
> 
>  - Introduce separate API for enter from a different thread
>  - Merge remote-tracking branch 'upstream_jdk/master' into JDK-8324881
>  - More restrictive API
>  - Add regression test
>  - 8324881: ObjectSynchronizer::inflate(Thread* current...) is invoked for non-current thread

Still seeing some timeouts after on windows debug. Might be that the monitorinflation trace logging + LM_MONITOR + debug makes this already slow test too slow for the default timeout window in our CI. Looking into it.

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PR Comment: https://git.openjdk.org/jdk/pull/17626#issuecomment-1920909606