[OMPI users] Memory corruption due to MPI_Status_c2f

[François Trahay]

Hi,
I have a C+Fortran program that seems to crash due to OpenMPI implementation 
of MPI_Status_c2f. When my program calls this function, a memory corruption 
happens.
Here's a test program that reproduce the bug. It allocates and fills a buffer, 
call MPI_Status_c2f (using a valid status) and print the buffer.
Before calling MPI_Status_c2f, the buffer contains (0,1,2,...31). After the 
function call, it contains(x, x, ...20, 21, 22, ...31)

From this example, it seems that the first 80 bytes (20 integers) of this 
buffer 
get corrupted.

I tried this program with open mpi 1.4.3, 1.4.4 and the latest nightly 
snapshot (openmpi-1.7a1r25487) and they all have the same bug. 

Any idea to solve this problem ?

Francois Trahay

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <mpi.h>

#define CANARI_SIZE 32
#define SIZE 100
#define TAG 1
#define TAG2 2

int main(int argc, char**argv)
{

  int comm_size, comm_rank;
  MPI_Init(&argc,&argv);

  MPI_Comm_size(MPI_COMM_WORLD, &comm_size);
  MPI_Comm_rank(MPI_COMM_WORLD, &comm_rank);

  if (comm_size != 2) {
    fprintf(stderr, "This program requires 2 MPI processes, aborting...\n");
    goto out;
  }

  char buffer[SIZE];
  MPI_Request req;
  MPI_Status status;
  char canari1[CANARI_SIZE];
  MPI_Fint f_status;
  char canari2[CANARI_SIZE];

  int i;

  if(comm_rank == 0) {
    memset(buffer, 0x11, SIZE);

    MPI_Irecv(buffer, SIZE, MPI_CHAR, 1, TAG, MPI_COMM_WORLD, &req);
    MPI_Wait(&req, &status);

    for(i=0;i<CANARI_SIZE;i++) {
      canari1[i] = i;
      canari2[i] = i;
    }

    printf("Before MPI_Status_f2c:\n");
    for(i=0;i<CANARI_SIZE;i++) {
      printf("%d\t %d\n", canari1[i], canari2[i]);
    }

    MPI_Status_c2f(&status, &f_status);

    printf("After MPI_Status_f2c:\n");
    for(i=0;i<CANARI_SIZE;i++) {
      printf("%d\t %d\n", canari1[i], canari2[i]);
    }


  } else {
    memset(buffer, 0x42, SIZE);
    MPI_Isend(buffer, SIZE, MPI_CHAR, 0, TAG, MPI_COMM_WORLD, &req);
    MPI_Wait(&req, MPI_STATUS_IGNORE);
  }

 out:
  MPI_Finalize();
  return 0;
}