RFR: 8297286: runtime/vthread tests crashing after JDK-8296324

[Serguei Spitsyn]

On Wed, 23 Nov 2022 02:17:43 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

>> This problem has two sides.
>> One is that the `VirtualThread::run() `cashes the field `notifyJvmtiEvents` value.
>> It caused the native method `notifyJvmtiUnmountBegin()` not called after the field `notifyJvmtiEvents`
>> value has been set to `true` when an agent library is loaded into running VM.
>> The fix is to get rid of this cashing.
>> Another is that enabling `notifyJvmtiEvents` notifications needs a synchronization.
>> Otherwise, a VTMS transition start can be missed which will cause some asserts to fire.
>> The fix is to use a JvmtiVTMSTransitionDisabler helper for sync.
>> 
>> Testing:
>> The originally failed tests are passed now:
>> 
>> runtime/vthread/RedefineClass.java
>> runtime/vthread/TestObjectAllocationSampleEvent.java 
>> 
>> In progress:
>> Run the tiers 1-6 to make sure there are no regression.
>
> src/java.base/share/classes/java/lang/VirtualThread.java line 273:
> 
>> 271:     private void run(Runnable task) {
>> 272:         assert state == RUNNING;
>> 273:         boolean notifyJvmti = notifyJvmtiEvents;
> 
> Don't we have same issue in yieldContinuation() method? (line 396)

Good point. I'll check and make an update if needed.
Thank you for looking at it.

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

PR: https://git.openjdk.org/jdk/pull/11304