RFR: 8212181: ZGC: Fix incorrect root iteration in ZHeapIterator

[Erik Österlund]

Hi Per,

Looks good.

Thanks,
/Erik

On 2018-10-15 16:44, Per Liden wrote:
> The ZHeapIterator should not make callbacks to the user supplied 
> ObjectClosure while iterating over roots. Instead all roots should be 
> pushed to the stack first, before any call to the user supplied 
> ObjectClosure is made. This is needed since the user supplied 
> ObjectClosure could otherwise modify the root set (e.g. the JVMTI 
> TagMap) while we're iterating over it, which can lead to memory 
> corruption.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8212181
> Webrev: http://cr.openjdk.java.net/~pliden/8212181/webrev.0
>
> /Per