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

[Coleen Phillmore]

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
>>
>