Hi Stefan

Don't you need to allocate xx, yy and conc, before you use them?
In the short program below, they are declared as allocatable,
but not actually allocated.

I hope this helps,
Gus Correa

On 01/11/2013 09:58 AM, Stefan Mauerberger wrote:
Dear Paul!

Thanks for your reply. This problem seems to get complicated.

Unfortunately, I can not reproduce what you are describing. I tried with
some GCCs as 4.7.1, 4.7.2 and 4.8.0 (20121008). As you suggested,
replacing the MPI_Init and MPI_Finalize calls with WRITE(*,*) "foooo"
and commenting out use mpi, everything is just fine. No segfault no core
dump, just the result as I expect it (I put a write(*,*) size(conc) in,
which must print 2). I simply compiled with a bare mpif90 ... and
executed typing mpirun -np 1 ./a.out .
I also tried on three different architectures - all 64-bit - and, as
soon as MPI_Init is invoked, the program gets core dumped.

I also tried with IBM's MPI implementation just with the difference
using include 'mpif.h' instead of use mpi. Everything is fine and the
result is as in serial runs.

Well, it's not surprising that 4.4.x has its problems. Using modern
Fortran as F03, GCC in a version younger than  4.7.x is just mandatory.

Cheers,
Stefan



On Fri, 2013-01-11 at 14:26 +0100, Paul Kapinos wrote:
This is hardly an Open MPI issue:

switch the calls to MPI_Init, MPI_Finalize against
WRITE(*,*) "foooo"
comment aut 'USE mpi' .... an see your error (SIGSEGV) again, now without any
MPI part in the program.
So my suspiction is this is an bug in your GCC version. Especially because there
is no SIGSEGV using 4.7.2 GCC (whereby it crasehs using 4.4.6)

==>  Update your compilers!


On 01/11/13 14:01, Stefan Mauerberger wrote:
Hi There!

First of all, this is my first post here. In case I am doing something
inappropriate pleas be soft with me. On top of that I am not quite sure
whether that issue is related to Open MPI or GCC.

Regarding my problem: Well, it is a little bulky, see below. I could
figure out that the actual crash is caused by invoking Fortran's array
constructor [ xx, yy ] on derived-data-types xx and yy. The one key
factor is that those types have allocatable member variables.
Well, that fact points to blame gfortran for that. However, the crash
does not occur if MPI_Iinit is not called in before. Compiled as a
serial program everything works perfectly fine. I am pretty sure, the
lines I wrote are valid F2003 code.

Here is a minimal working example:
PROGRAM main
      USE mpi

      IMPLICIT NONE

      INTEGER :: ierr

      TYPE :: test_typ
          REAL, ALLOCATABLE :: a(:)
      END TYPE

      TYPE(test_typ) :: xx, yy
      TYPE(test_typ), ALLOCATABLE :: conc(:)

      CALL mpi_init( ierr )

      conc = [ xx, yy ]

      CALL mpi_finalize( ierr )

END PROGRAM main
Just compile with mpif90 ... and execute leads to:
*** glibc detected *** ./a.out: free(): invalid pointer: 0x00007fefd2a147f8 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x7eb96)[0x7fefd26dab96]
./a.out[0x400fdb]
./a.out(main+0x34)[0x401132]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed)[0x7fefd267d76d]
./a.out[0x400ad9]
With commenting out 'CALL MPI_Init' and 'MPI_Finalize' everything seems to be 
fine.

What do you think: Is this a OMPI or a GCC related bug?

Cheers,
Stefan


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