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

Aleksey Shipilev shade at redhat.com
Tue Feb 4 19:33:28 UTC 2020


On 2/4/20 8:29 PM, Zhengyu Gu wrote:
> 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.

Right. There is still plenty of time to fix 11. Let's not rush it in 14.

-- 
Thanks,
-Aleksey



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