[14] 8237632: Shenandoah fails some vmTestbase_nsk_jvmti tests with "Forwardee must point to a heap address"

[Zhengyu Gu]

On 2/4/20 2:23 PM, Aleksey Shipilev wrote:
> On 2/3/20 9:59 PM, Zhengyu Gu wrote:
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8237632
>> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8237632/webrev.00/
> 
> Uh. It seems to me the cure is worse than the disease:
>    1) It rewires sensitive parts of barrier paths, root handling, etc, which requires more thorough
> testing, and we are too deep in RDP2 for this;
>    2) It effectively disables asserts for anything not in collection set. Which means it disables
> most of asserts. The fact that Verifier still works is a small consolation.
> 
> I propose to accept this failure in 14, and rework the JVMTI heap walk to stop messing around with
> mark words in 15. Since this relates to concurrent root handling, 11-shenandoah is already safe.

I have yet to test 11-shenandoah. But performing JVMTI heap walk during 
evacuation phase, still sounds the alarm to me.

-Zhengyu

>