RFR: 8288139: JavaThread touches oop after GC barrier is detached [v3]

[Daniel D. Daugherty]

On Fri, 17 Jun 2022 15:39:10 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:

>> Update SharedRuntime::get_java_tid() to verify that the calling thread is safely
>> accessing its own threadObj(). This check uses the new is_gc_barrier_detached()
>> function added by [JDK-8288497](https://bugs.openjdk.org/browse/JDK-8288497) add support for JavaThread::is_gc_barrier_detached().
>> 
>> The above check was used to reproduce the failure mode without Shenandoah
>> and the remainder of the fix relocates the offending code from
>> ThreadsSMRSupport::remove_thread() to Threads::remove(). The work of
>> removed the 'tid' entry from the ThreadIdTable is still done under the
>> protection of the Threads_lock.
>> 
>> This fix along with the fix for JDK-8288497 has been tested in Mach5 Tier[1-8].
>> There are no related failures in Mach5 Tier[1-7]; Mach5 Tier8 is still running.
>
> Daniel D. Daugherty 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:
> 
>  - update after 8288497 v01 code review changes
>  - Merge branch 'JDK-8288497' into JDK-8288139
>  - update after 8288497 v00 code review changes
>  - Merge branch 'JDK-8288497' into JDK-8288139
>  - 8288139: JavaThread touches oop after GC barrier is detached

The latest version's Mach5 Tier[1-7] looks good. Mach5 Tier8 was just started.

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

PR: https://git.openjdk.org/jdk19/pull/21