RFR: 8336846: assert(state->get_thread() == jt) failed: handshake unsafe conditions [v4]

[Alex Menkov]

On Tue, 6 Aug 2024 21:06:45 GMT, Serguei Spitsyn <sspitsyn at openjdk.org> wrote:

>> The JVMTI Watch Field functions do not disable VTMS transitions with the `JvmtiVTMSTransitionDisabler`:
>> - `SetFieldAccessWatch()`
>> - `ClearFieldAccessWatch()`
>> - `SetFieldModificationWatch()`
>> - `ClearFieldModificationWatch()`
>>  so in the `recompute_enabled()` we could see that a vthread is mounted, but in the `EnterInterpOnlyModeClosure` handshake the thread could have been unmounted already. This is a root cause of failures with this assert.
>>  
>> The fix is to disable transitions in the `JvmtiEventControllerPrivate::change_field_watch()` function.
>> 
>> Testing:
>> - TBD: submit mach5 tiers 1-6
>
> Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:
> 
>   use MUTEX_DEFL instead of MUTEX_DEFN to define JvmtiVTMSTransition_lock

Marked as reviewed by amenkov (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/20413#pullrequestreview-2223285620