RFR(XS) 8252593: [TESTBUG] serviceability/jvmti/GetLocalVariable/GetLocalWithoutSuspendTest.java failed with JVMTI_ERROR_INVALID_SLOT

[David Holmes]

Hi Richard,

On 3/09/2020 12:37 am, Reingruber, Richard wrote:
> Hi,
> 
> please help review this fix for  a TESTBUG in
> serviceability/jvmti/GetLocalVariable/GetLocalWithoutSuspendTest.java
> 
> Webrev: http://cr.openjdk.java.net/~rrich/webrevs/8252593/webrev.0/
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8252593
> 
> With this change the JVMTI test agent silently accepts 
> JVMTI_ERROR_INVALID_SLOT as result of a JVMTI GetLocalObject() call.
> The target frame of the call varies because the target thread is running. In
> rare cases it might not be one of the many frames of
> GetLocalWithoutSuspendTest.recursiveMethod() as intended but the frame 
> of a static method without parameters which the target thread might call after 
> returning from all the recursive calls. This would result in JVMTI_ERROR_INVALID_SLOT.
> 
> Anyway JVMTI_ERROR_INVALID_SLOT has to be expected and should be silently
> ignored.
> 
> Furthermore I have corrected the type of the parameter waitCycles of
> Java_GetLocalWithoutSuspendTest_notifyAgentToGetLocal() to be jint. Now it
> matches the declaration in GetLocalWithoutSuspendTest.java.

Hmmm ... could this mean that the attempt to read a 64-bit value where 
only a 32-bit value had actually been pushed as a parameter, could 
result in reading a junk value that sometimes caused the loop to exit 
immediately?

David

> Thanks, Richard.
>