[mpich2-dev] shared-lib builds, MPE, and SELinux en ENFORCING mode

[Lisandro Dalcin]

On Thu, May 21, 2009 at 12:07 PM, Dave Goodell <goodell at mcs.anl.gov> wrote:
> Solution (2) that you outlined below is planned, we just haven't implemented
> it yet.  I believe that this is being tracked by ticket #573 [1].

Nice.

>  In the
> mean time, does putting "-fPIC" in your CFLAGS serve as solution (1)?
>

Yes, of course...


> -Dave
>
> [1] https://trac.mcs.anl.gov/projects/mpich2/ticket/573
>
> On May 21, 2009, at 9:45 AM, Lisandro Dalcin wrote:
>
>> Just built 1.1rc1 with shared libraries, and then tried to build
>> mpi4py's Python extension module (a dlpen()'able shared lib) with MPE
>> (by passing -mpi=mpilog to mpicc). When I try to import my extension
>> module, I get:
>>
>> $ python
>>>>>
>>>>> from mpi4py import MPI
>>
>> Traceback (most recent call last):
>>  File "<stdin>", line 1, in <module>
>> ImportError: /u/dalcinl/lib/python/mpi4py/MPI.so: cannot restore
>> segment prot after reloc: Permission denied
>>>>>
>>
>> This happens because I have SELinux enabled in ENFORCING and because
>> the MPE sources were not compiled with -fPIC
>>
>> $ eu-findtextrel /u/dalcinl/lib/python/mpi4py/MPI.so
>>
>> /u/dalcinl/BUILD/MPI/mpich2-1.1rc1/src/mpe2/src/wrappers/src/log_mpi_core.c
>> not compiled with -fpic/-fPIC
>> <...more-output...>
>>
>> and then my "MPI.so" extension module requires relocation on loading
>> (and this is prohibited by SELinux in ENFORCING mode).
>>
>> This could be solved (apart from asking me to use "chcon -t
>> texrel_shlib_t ...") by two ways:
>>
>> 1) Use -fPIC for compiling the MPE sources, but continue building the
>> MPE libs as static ones.
>> 2) Also build shared libs for MPE.
>>
>> (1) is easy and definitely works on Linux, though I do not know if
>> this is valid on other systems.
>> (2) is the definitive solution, but perhaps a bit harder to implement
>> because of the required modifications to MPICH2's buildsystem.
>>
>>
>>
>> --
>> Lisandro Dalcín
>> ---------------
>> Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
>> Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
>> Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
>> PTLC - Güemes 3450, (3000) Santa Fe, Argentina
>> Tel/Fax: +54-(0)342-451.1594
>
>



-- 
Lisandro Dalcín
---------------
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
PTLC - Güemes 3450, (3000) Santa Fe, Argentina
Tel/Fax: +54-(0)342-451.1594