RFR (XS) 6988950: JDWP exit error JVMTI_ERROR_WRONG_PHASE(112)

[Staffan Larsen]

This looks good - and thanks for the detailed description!

My only comment is that you chose to ignore the error in only some of the methods - I assume these were the methods where you have encountered a problem in. Should we write a comment about that, or should we ignore the error in all methods?

/Staffan

On 29 okt 2014, at 02:11, serguei.spitsyn at oracle.com wrote:

> Please, review the fix for:
>  https://bugs.openjdk.java.net/browse/JDK-6988950
> 
> 
> Open webrev:
> http://cr.openjdk.java.net/~sspitsyn/webrevs/2014/jdk/6988950-JDWP-wrong-phase.1/
> 
> 
> Summary:
> 
>   The failing scenario:
>     The debugger and the debuggee are well aware a VM shutdown has been started in the target process.
>     The debugger at this point is not expected to send any commands to the JDWP agent.
>     However, the JDI layer (debugger side) and the jdwp agent (debuggee side)
>     are not in sync with the consumer layers.
> 
>     One reason is because the test debugger does not invoke the JDI method VirtualMachine.dispose().
>     Another reason is that the Debugger and the debuggee processes are uneasy to sync in general.
> 
>     As a result the following steps are possible:
>       - The test debugger sends a 'quit' command to the test debuggee
>       - The debuggee is normally exiting
>       - The jdwp backend reports (over the jdwp protocol) an anonymous class unload event
>       - The JDI InternalEventHandler thread handles the ClassUnloadEvent event
>       - The InternalEventHandler wants to uncache the matching reference type.
>         If there is more than one class with the same host class signature, it can't distinguish them,
>         and so, deletes all references and re-retrieves them again (see tracing below):
>           MY_TRACE: JDI: VirtualMachineImpl.retrieveClassesBySignature: sig=Ljava/lang/invoke/LambdaForm$DMH;
>       - The jdwp backend debugLoop_run() gets the command from JDI and calls the functions
>         classesForSignature() and classStatus() recursively.
>       - The classStatus() makes a call to the JVMTI GetClassStatus() and gets the JVMTI_ERROR_WRONG_PHASE
>       - As a result the jdwp backend reports the JVMTI error to the JDI, and so, the test fails
> 
>     For details, see the analysis in bug report closed as a dup of the bug 6988950:
>        https://bugs.openjdk.java.net/browse/JDK-8024865
> 
>     Some similar cases can be found in the two bug reports (6988950 and 8024865) describing this issue.
> 
>     The fix is to skip reporting the JVMTI_ERROR_WRONG_PHASE error as it is normal at the VM shutdown.
>     The original jdwp backend implementation had a similar approach for the raw monitor functions.
>     Threy use the ignore_vm_death() to workaround the JVMTI_ERROR_WRONG_PHASE errors.
>     For reference, please, see the file: src/share/back/util.c
> 
> 
> Testing:
>  Run nsk.jdi.testlist, nsk.jdwp.testlist and JTREG com/sun/jdi tests
> 
> 
> Thanks,
> Serguei
>