[8u40] RFR: 8064556: G1: ParallelGCThreads=0 may cause assert(!MetadataOnStackMark::has_buffer_for_thread(Thread::current())) failed: Should be empty

[Stefan Karlsson]

On 2014-11-11 16:45, Thomas Schatzl wrote:
> Hi,
>
> On Tue, 2014-11-11 at 13:58 +0100, Stefan Karlsson wrote:
>> Hi all,
>>
>> Please review this patch to weaken the failing assert:
>>    http://cr.openjdk.java.net/~stefank/8064556/webrev.01
>>    https://bugs.openjdk.java.net/browse/JDK-8064556
>>
>> The asserts in pre_work_verification and post_work_verification were put
>> in place to make sure that the worker threads entered and exited with
>> clean slates. However, in JDK 8 this code path can be taken by the
>> VMThread, which will have registered Metadata when running the
>> MetadataOnStackMark constructor in the unloading phase of
>> ConcurrentMark::weakRefsWork. This is different from JDK 9, which always
>> use worker threads to execute this path.
>>
>> The patch has been verified with the failing test that found this issue.
>    looks good.

Thanks, Thomas.

StefanK

>
> Thomas
>
>