Dear MPI users,

I am struggling against the bad behaviour of a MPI code. These are the basic informations:

a) fortran intel11 or intel 12 and OpenMPI 1.4.1 and 1.4.3 give the same problem. activating -traceback compiler option, I see the program stops at MPI_Waitany. MPI_Waitany waits for the completion of an array of MPI_IRecv: looping for the number of array components at the end all receives should be completed.
The programs stops at unpredictable points (after 1 or 5 or 24 hours of computation). Sometimes I have sigsegv:  00002BA74D29D181  Unknown               Unknown  Unknown  00002BA74D29C6FF  Unknown               Unknown  Unknown  00002BA74D29C033  Unknown               Unknown  Unknown   00002BA74835C3E6  Unknown               Unknown  Unknown        00002BA747E485AD  Unknown               Unknown  Unknown        00002BA747E7857D  Unknown               Unknown  Unknown    00002BA747C047C4  Unknown               Unknown  Unknown
cosa.mpi           00000000004F856B  waitanymessages_         1292  parallelutils.f
cosa.mpi           00000000004C8044  cutman_q_                2084  bc.f
cosa.mpi           0000000000413369  smooth_                  2029  cosa.f
cosa.mpi           0000000000410782  mg_                       810  cosa.f
cosa.mpi           000000000040FB78  MAIN__                    537  cosa.f
cosa.mpi           000000000040C1FC  Unknown               Unknown  Unknown          00002BA7490AE994  Unknown               Unknown  Unknown
cosa.mpi           000000000040C109  Unknown               Unknown  Unknown
mpirun has exited due to process rank 34 with PID 10335 on
node neo251 exiting without calling "finalize". This may
have caused other processes in the application to be
terminated by signals sent by mpirun (as reported here).

Waitanymessages is just a wrapper of MPI_Waitany. Sometimes, the run stops writing anything on screen and I do not know what is happening (probably MPI_Waitany hangs). Before reaching segafault or hanging, results are always correct, as checked using the serial version of the code.

b) The problem occurs only using openib (using TCP/IP it works) and only using more than one node on our main cluster . Trying many possibile workarounds, I found that running using:

-mca btl_openib_use_eager_rdma 0 -mca btl_openib_max_eager_rdma 0 -mca btl_openib_flags 1

the problems seems not to occur.

I would be very thankful to anyone which can help me to make us sure there is no bug in the code and, anyway, to discover the reason of such a "dangerous" behaviour.

I can give any further information if needed, and I apologize if the post is not enough clear or complete.