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Subject: Re: [OMPI users] Potential bug in creating MPI_GROUP_EMPTY handling
From: Dominik Goeddeke (dominik.goeddeke_at_[hidden])
Date: 2011-03-17 18:40:31


glad we could help and the two hours of stripping things down were
effectively not wasted. Also good to hear (implicitly) that we were not
too stupid to understand the MPI standard...

Since to the best of my understanding, our workaround is practically
overhead-free, we went ahead and coded everything up analogously to the
workaround, i.e. we don't rely on / wait for an immediate fix.

Please let us know if further information is needed.

Thanks,

dom

On 03/17/2011 05:10 PM, Jeff Squyres wrote:
> Sorry for the late reply, but many thanks for the bug report and reliable reproducer.
>
> I've confirmed the problem and filed a bug about this:
>
> https://svn.open-mpi.org/trac/ompi/ticket/2752
>
>
> On Mar 6, 2011, at 6:12 PM, Dominik Goeddeke wrote:
>
>> The attached example code (stripped down from a bigger app) demonstrates a way to trigger a severe crash in all recent ompi releases but not in a bunch of latest MPICH2 releases. The code is minimalistic and boils down to the call
>>
>> MPI_Comm_create(MPI_COMM_WORLD, MPI_GROUP_EMPTY,&dummy_comm);
>>
>> which isn't supposed to be illegal. Please refer to the (well-documented) code for details on the high-dimensional cross product I tested (on ubuntu 10.04 LTS), a potential workaround (which isn't supposed to be necessary I think) and an exemplary stack trace.
>>
>> Instructions: mpicc test.c -Wall -O0&& mpirun -np 2 ./a.out
>>
>> Thanks!
>>
>> dom
>>
>>
>> <test.c>_______________________________________________
>> users mailing list
>> users_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>

-- 
Dr. Dominik Göddeke
Institut für Angewandte Mathematik
Technische Universität Dortmund
http://www.mathematik.tu-dortmund.de/~goeddeke
Tel. +49-(0)231-755-7218  Fax +49-(0)231-755-5933