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List:       openjdk-serviceability-dev
Subject:    Re: RFR: 8295816: jdwp jck tests failing with "FATAL ERROR in native method: JDWP SetTag,
From:       Chris Plummer <cjplummer () openjdk ! org>
Date:       2022-10-25 22:15:23
Message-ID: 8g9Hkbf5ntaOOlMurE46gMFmvCUFQ30MiA3EG7jMCJ8=.26f03e8d-e7e2-4bb5-a722-136094ff6ead () github ! com
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On Mon, 24 Oct 2022 05:29:26 GMT, Chris Plummer <cjplummer@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 reviews!

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

PR: https://git.openjdk.org/jdk/pull/10831


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