MPI_Free_mem fails with a segmentation fault using OpenMPI

Question

I am using OpenMPI with the Intel C++ compiler on an Intel Ubuntu system. Whenever I try to replace new[] and delete[] calls with MPI_Alloc_mem and MPI_Free_mem calls, respectively, I always get a segmentation fault.

The MPI_Alloc_mem calls return MPI_SUCCESS. The segmentation fault occurs on the call to MPI_Free_mem. The MPI_Alloc_mem calls are with MPI_INFO_NULL. I explicitly typecast the void** and void* arguments in MPI_Alloc_mem and MPI_Free_memrespectively.

I have no idea why this happens. I'd appreciate any advice.

Your code contains error. Probably on line #42. – Öö Tiib Mar 01 '13 at 06:56 — Öö Tiib, Mar 01 '13 at 06:56

score 0 · Answer 1 · answered Mar 01 '13 at 12:37

First of all, unless you are going to use MPI-2 one-sided communication, there is absolutely no need to replace C++ memory management operators with MPI calls.

Second, the correct usage of MPI_ALLOC_MEM and MPI_FREE_MEM in C/C++ is as follows:

int *arr;

MPI_Alloc_mem(sizeof(int)*1000, MPI_INFO_NULL, &arr); // <-- here arr by address
...
MPI_Free_mem(arr);                                    // <-- here arr by value

MPI_Free_mem fails with a segmentation fault using OpenMPI

1 Answers1