RFR: 8266593: vmTestbase/nsk/jvmti/PopFrame/popframe011 fails with "assert(java_thread == _state->get_thread()) failed: Must be"

[Serguei Spitsyn]

On Wed, 17 Nov 2021 22:21:33 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

> The test fails when the target JavaThread has is_exiting() status. In such a case the JvmtiExport::cleanup_thread(this) has already made a clean up of its jvmtiThreadState, so the JavaThread address returned by _state->get_thread() is 0xbabababababababa.
> The fix is to add a check for is_exiting() status into handshake closure do_thread() early.
> There following handshake closures are fixed by this update:
>   - UpdateForPopTopFrameClosure
>  - SetForceEarlyReturn
>  - SetFramePopClosure

Hi David,

Thank you for reviewing this!
I was also thinking about getting rid of the check `java_thread->threadObj() == NULL`. 
Then I've decided it is safe to keep it as it was in the original UpdateForPopTopFrameClosure implementation (but later in the code). I will remove it and retest the fix.

> Second, if the target thread is exiting then surely the suspension check should return
> false and so we would already give a JVMTI_ERROR_THREAD_NOT_SUSPENDED error?

The assert 
`   assert(java_thread == _state->get_thread(), "Must be");`
is fired one line before the `JVMTI_ERROR_THREAD_NOT_SUSPENDED` code is returned.

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PR: https://git.openjdk.java.net/jdk/pull/6440