RFR: 8215773: applications/kitchensink/Kitchensink.java crash with "assert(ZAddress::is_marked(addr)) failed: Should be marked"

[Erik Österlund]

Hi Per,

Thanks for the review.

/Erik

On 2019-01-07 09:14, Per Liden wrote:
> On 1/4/19 11:10 AM, Erik Österlund wrote:
>> Hi,
>>
>> During SystemDictionary::do_unloading(), JFR pokes around at the dead 
>> mirror oops that died due to class unloading.
>> The mirror is loaded without AS_NO_KEEPALIVE, which makes ZGC load 
>> barriers a bit sad, because they dislike loading dead oops.
>>
>> The solution is to load these mirrors with AS_NO_KEEPALIVE 
>> decorators, indicating that it is okay for them to be dead as we are 
>> only peeking at them. This is fine to do during concurrent execution 
>> by the GC thread that is performing class unloading, and hence 
>> controls the GC cycle, making sure that the memory of the dead oops 
>> is not reclaimed until the accesses have safely finished.
>>
>> Bug:
>> https://bugs.openjdk.java.net/browse/JDK-8215773
>>
>> Webrev:
>> http://cr.openjdk.java.net/~eosterlund/8215773/webrev.00/
>
> Looks good.
>
> /Per
>
>>
>> Manually ran kitchensink 24 hours to make sure this doesn't happen 
>> again. And hs-tier1-6 on linux.
>>
>> Thanks,
>> /Erik