On Mon, 24 Oct 2022 05:29:26 GMT, Chris Plummer <cjplum...@openjdk.org> wrote:
> Various debugger tests (mainly JCK vm/jdwp tests) are failing with: > > `FATAL ERROR in native method: JDWP SetTag, > jvmtiError=JVMTI_ERROR_WRONG_PHASE(112) ` > > Sometimes instead of `SetTag` the message says `GetTag` or `signature`. This > is a new issue caused by > [JDK-8295375](https://bugs.openjdk.org/browse/JDK-8295375), which changed the > debug agent CLASS_PREPARE event handling that is used for class tracking. It > moved it from the main debug agent JVMTIEnv to a JVMTIEnv that already > existed for class tracking purposes to deal with OBJECT_FREE events. Because > of this, synchronizing around VMDEATH was lost, so it's possible for the > CLASS_PREPARE event to be received just before VMDEATH, but then VMDEATH > completes before the CLASS_PREPARE callback can complete. This results in > WRONG_PHASE errors when making some JVMTI calls. > > The easiest fix is for the code in `classTrack_addPreparedClass()` to check > for JVMTI_ERROR_WRONG_PHASE, and if it gets it then just return. It should > also assert that `gData->vmDead` is true when this happens. This is needed in > 3 places where JVMTI is called. > > The purist fix would be to somehow synchronize with VMDEATH, either with the > same locking done by the main event handling code (for example, use > BEGIN_CALLBACK and END_CALLBACK), or by having the class tracking JVMTIEnv > also enable VMDEATH events. The VMDEATH callback block would disable the > CLASS_PREPARE events, and also block until any currently executing > CLASS_PREPARE callback has exited. I think this is overkill, and also adds > locking overhead to the CLASS_PREPARE callback, so I'm going with the simpler > solution of allowing WRONG_PHASE. Thanks for the review Serguei! Can I get one more review please. The failures are getting rather noisy, so I'd like to get this fix pushed. Thanks. ------------- PR: https://git.openjdk.org/jdk/pull/10831
