Review Request (S) 8028126: nsk/jvmti/scenarios/hotswap/HS101/hs101t006 Crashed the vm on Solaris-sparc64 fastdebug builds: only current thread can flush its registers

[David Holmes]

Hi Serguei,

This looks fine to me. Definitely low risk but not sure it is critical 
enough for 8.

Minor nit:
   _method_id = (jmethodID)NULL;

It should never be necessary to cast NULL if assigning to a pointer type.

Thanks,
David

On 27/11/2013 11:34 AM, serguei.spitsyn at oracle.com wrote:
> Please, review the fix for:
>    https://bugs.openjdk.java.net/browse/JDK-8028126
>
> Open webrev:
> http://cr.openjdk.java.net/~sspitsyn/webrevs/2013/hotspot/8028126-JVMTI-HS101.1/
>
>
> Summary:
>    This is a fix for a possible race condition between the
> VMOp_GetCurrentLocation
>    reaching a safepoint and target debuggee thread exiting from Java
> execution.
>    The fix is to recheck the existence of the last Java frame at a
> safepoint
>    and clean the thread current location if the thread has been already
> exited from Java.
>
>    I'm suggesting to fix this in hs25/JDK 8.
>    It is important to fix as it is a P2 bug and the risk of fixing it is
> low.
>    But need reviewers to share opinions on this.
>    I'll add the 8-critical-request label if reviewers agree with the above.
>
>
> Testing:
>    The test nsk/jvmti/scenarios/hotswap/HS101/hs101t006 that was
> originally failed.
>    In progress: nsk.jvmti, nsk.jdi, nsk.jdwp
>
>
> Thanks,
> Serguei