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

[Daniel D. Daugherty]

 > http://cr.openjdk.java.net/~coleenp/8009836_2/

src/share/vm/memory/metablock.cpp
     The new fill_to_aligned_words() call doesn't specify what to fill with.
     Does that default to zero? If so then, OK. If not, then...

src/share/vm/oops/constMethod.cpp
src/share/vm/oops/method.cpp
     These two look the same as before so OK.

Dan


On 3/13/13 6:14 AM, 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
>>>
>>
>