[11u] RFR (S) 8235324: Dying objects are published from users of CollectedHeap::object_iterate

[Stefan Karlsson]

Looks good.

Thanks,
StefanK

On 2021-02-03 11:59, Aleksey Shipilev wrote:
> Original bug:
>   https://bugs.openjdk.java.net/browse/JDK-8235324
>   https://hg.openjdk.java.net/jdk/jdk/rev/35d8d9b65744
>
> The patch applies almost cleanly to 11u. The only conflict I have to 
> resolve is in zBarrier.hpp, where context is different. The patch 
> itself is simple: keep-alive things that we touch with object_iterate, 
> in case we load them with non-keepalive barriers.
>
> 11u variant:
>   https://cr.openjdk.java.net/~shade/8235324/webrev.11u.01/
>
> It requires two follow ups that unbreak Shenandoah, to be backported 
> at the same time
>  8237369: Shenandoah: failed 
> vmTestbase/nsk/jvmti/AttachOnDemand/attach021/TestDescription.java test
>  8237392: Shenandoah: Remove unreliable assertion
>
> Testing: tier{1,2,3} with {G1, Shenandoah, ZGC, Parallel}; 
> vmTestbase_nsk_jvmti with {G1, Shenandoah, ZGC, Parallel}
>