On 1/28/2013 11:48 AM, Ralph Castain wrote:
On Jan 28, 2013, at 9:12 AM, Steve Wise <sw...@opengridcomputing.com> wrote:
On 1/25/2013 12:19 PM, Steve Wise wrote:
Hello,
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?
Thanks,
Steve.
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.
Thanks,
Steve.
