Hmmm...afraid I cannot replicate this using the current state of the 1.6 branch (which is the 1.6.4rcN) on the only IB-based cluster I can access.
Can you try it with a 1.6.4 tarball and see if you still see the problem? Could be someone already fixed it.
On Jan 28, 2013, at 10:03 AM, Steve Wise <swise_at_[hidden]> wrote:
> On 1/28/2013 11:48 AM, Ralph Castain wrote:
>> On Jan 28, 2013, at 9:12 AM, Steve Wise <swise_at_[hidden]> wrote:
>>> On 1/25/2013 12:19 PM, Steve Wise wrote:
>>>> I'm tracking an issue I see in openmpi-1.6.3. Running this command on my chelsio iwarp/rdma setup causes a seg fault every time:
>>>> /usr/mpi/gcc/openmpi-1.6.3-dbg/bin/mpirun --np 2 --host hpc-hn1,hpc-cn2 --mca btl openib,sm,self --mca btl_openib_ipaddr_include "192.168.170.0/24" /usr/mpi/gcc/openmpi-1.6.3/tests/IMB-3.2/IMB-MPI1 pingpong
>>>> The segfault is during finalization, and I've debugged this to the point were I see a call to dereg_mem() after the openib blt is unloaded via dlclose(). dereg_mem() dereferences a function pointer to call the btl-specific dereg function, in this case it is openib_dereg_mr(). However, since that btl has already been unloaded, the deref causes a seg fault. Happens every time with the above mpi job.
>>>> Now, I tried this same experiment with openmpi-1.7rc6 and I don't see the seg fault, and I don't see a call to dereg_mem() after the openib btl is unloaded. That's all well good. :) But I'd like to get this fix pushed into 1.6 since that is the current stable release.
>>>> Question: Can someone point me to the fix in 1.7?
>>> It appears that in ompi_mpi_finalize(), mca_pml_base_close() is called which unloads the openib btl. Then further down in ompi_mpi_finalize(), mca_mpool_base_close() is called which ends up calling dereg_mem() which seg faults trying to call into the unloaded openib btl.
>> That definitely sounds like a bug
>>> Anybody have thoughts? Anybody care? :)
>> I care! It needs to be fixed - I'll take a look. Probably something that forgot to be cmr'd.
> Great! If you want me to try out a fix or gather more debug, just hollar.