RFR: 8307153: JVMTI GetThreadState on carrier should return STATE_WAITING [v2]

[Alex Menkov]

On Mon, 5 Jun 2023 19:00:49 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> When a virtual thread is mounted, the carrier thread should be reported as "waiting" until the virtual thread unmounts. Right now, GetThreadState reports a state based the JavaThread status when it should return JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY.
>> The fix adds:
>>  - a special case for passive carrier threads
>>  - necessary test coverage to the existing JVMTI test: `serviceability/jvmti/vthread/ThreadStateTest`.
>> 
>> Testing:
>>    - tested with the updated test: `serviceability/jvmti/vthread/ThreadStateTest`
>>    - submitted mach5 tiers 1-5
>>    - TBD: to submit mach5 tier 6
>
> Serguei Spitsyn 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 three additional commits since the last revision:
> 
>  - Merge
>  - minor tweaks in libThreadStateTest.cpp
>  - 8307153: JVMTI GetThreadState on carrier should return STATE_WAITING

src/hotspot/share/prims/jvmtiEnvBase.cpp line 764:

> 762: 
> 763:   if (is_passive_carrier_thread(jt, thread_oop)) {
> 764:     state |= (JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY);

Not sure I understand this.
I'd expect 
`JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY` to be returned in the case.
How can a thread be JVMTI_THREAD_STATE_RUNNABLE and JVMTI_THREAD_STATE_WAITING at the same time?

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PR Review Comment: https://git.openjdk.org/jdk/pull/14298#discussion_r1220384120