RFR (urgent, S): 8009836: nsk/regression/b4222717 fails with empty stack trace (new, still urgent!)

[Coleen Phillmore]

Thanks Rickard and David!
Coleen

On 3/13/2013 9:12 AM, Rickar
d Bäckman wrote:
> Coleen,
>
> this looks good to me.
>
> /R
>
> On Mar 13, 2013, at 1:14 PM, Coleen Phillmore wrote:
>
>> Summary: Some zeroing was missed for bug 8003553, causing empty stack traces and Xcomp crashes, add back zeroing to metablock
>>
>> I'll file a new bug to take more time and work on the missing zeroing.
>>
>> http://cr.openjdk.java.net/~coleenp/8009836_2/
>>
>> JPRT found this and so did runThese -Xcomp product which is a configuration that in retrospect, I should have tested.   Good thing we have hotspot-rt repository because this would have wreaked havoc in the compiler baseline.
>>
>> Thanks,
>> Coleen
>>
>> On 3/12/2013 2:04 PM, Coleen Phillimore wrote:
>>> Thank you for the code review, Dan.
>>>
>>> On 03/12/2013 11:00 AM, Daniel D. Daugherty wrote:
>>>> On 3/12/13 7:52 AM, Coleen Phillimore wrote:
>>>>> Summary: zero bit fields missed in Method* and ConstMethod*
>>>>>
>>>>> Tested with JPRT and failed test.   The other tests didn't find this omission.
>>>>> This bug might be causing JPRT c1 tests to get SEGV with stack overflows too on the hotspot-rt baseline.
>>>>>
>>>>> open webrev at http://cr.openjdk.java.net/~coleenp/8009836/
>>>>> bug link at http://bugs.sun.com/view_bug.do?bug_id=8009836
>>>> src/share/vm/oops/constMethod.cpp
>>>>     No comments.
>>>>
>>>> src/share/vm/oops/method.cpp
>>>>     No comments.
>>>>
>>>> Maybe I'm being dense, but I don't see the connection between
>>>> these code changes and the failure mode we're seeing. Can you
>>>> explain the connection between these changes and the missing
>>>> stack traces?
>>>>
>>> In javaClasses.cpp at line 1560, the method was marked as hidden randomly on solaris sparc probably because of the endianness.
>>>
>>>     if (method->is_hidden()) {
>>>       if (skip_hidden)  continue;
>>>     }
>>>     bt.push(method, bci, CHECK);
>>>     total_count++;
>>>
>>>> I'm going to guess that the fields that were not explicitly
>>>> zero were randomly non-zero on some of the Solaris SPARC configs
>>>> and that caused some confusion.
>>> yes.  I have a feeling that setting flags dont_inline and force_inline could also cause confusion but the confusion there was more subtle.
>>>>
>>>> How do we know whether all the fields have been properly
>>>> initialized?
>>> I had some temporary code that checked for the pattern 0xf1 from p = this to p< header_size() and manually checked the exceptions. We have a lot of gaps in instanceKlass so I couldn't leave the debugging code in.  So I checked them manually, unfortunately.
>>>
>>> thanks,
>>> Coleen
>>>>
>>>> Dan
>>>>
>>>>>
>>>>> Thanks,
>>>>> Coleen