[9] RFR (S): 8060147: SIGSEGV in Metadata::mark_on_stack() while marking metadata in ciEnv

[Vladimir Kozlov]

I am fine with targeted fix only.

One comment env->get_instance_klass() checks for NULL. Your new code in 
create_new_metadata() does not:

ciInstanceKlass* holder = 
get_metadata(h_m()->method_holder())->as_instance_klass();

Thanks,
Vladimir K

On 11/5/14 9:02 AM, Vladimir Ivanov wrote:
>
> On 11/5/14, 9:33 PM, Coleen Phillimore wrote:
>>
>> On 10/30/14, 4:32 PM, Vladimir Ivanov wrote:
>>> Coleen,
>>>
>>> I implemented 2 approaches of the fix.
>>>
>>> The fix with a special case for VM anon classes is:
>>> http://cr.openjdk.java.net/~vlivanov/8060147/webrev.anon.00/
>>>
>>> Both fix the bug, but have different properties.
>>>
>>> (1) Special case for VM anon class is very focused on the actual
>>> cause, but more fragile - all the logic which keeps metadata from
>>> being deallocated is non-trivial and scattered around the whole
>>> ciMetadata hierarchy.
>>>
>>> (2) On the other hand, initial version, which forcibly creates
>>> klass_holder ciObject for each ciMetadata, is much cleaner and
>>> localized, but does unnecessary work.
>>>
>>> Am I right that you prefer (1) as a fix?
>>
>> Yes, I think this version does less unnecessary work and creates less
>> ciObjects.   And the comment is useful for finding how we keep
>> ciMetadata alive for anonymous classes.   You still have a UseNewCode in
>> the webrev thought that you want to take out.
>
> Thanks, Coleen.
>
> VladimirK, Roland, what do you think about (1)?
>
> Best regards,
> Vladimir Ivanov