RFR (S) 8173361: various crashes in JvmtiExport::post_compiled_method_load

[coleen.phillimore at oracle.com]

On 11/14/19 8:34 PM, David Holmes wrote:
> Hi Coleen,
>
> On 15/11/2019 11:15 am, coleen.phillimore at oracle.com wrote:
>> Summary: Don't post information which uses metadata from unloaded 
>> nmethods
>>
>> Tested tier1-3 and 100 times with test that failed (reproduced 
>> failure without the fix).
>>
>> open webrev at 
>> http://cr.openjdk.java.net/~coleenp/2019/8173361.01/webrev
>> bug link https://bugs.openjdk.java.net/browse/JDK-8173361
>
> Fix looks fine. Do we want assert "nm->method() != NULL" somewhere?

I could add an assert below the if, but the application will crash in a 
few lines later if it's null.

I'd also tested a version that had:

    if (nm->method() == NULL) {
       return;
    }

but thought is_alive was a more accurate test.

thanks,
Coleen
>
> Thanks,
> David
>
>> Thanks,
>> Coleen