Error running mpirun on a 3D traction problem

Hello everyone, I am actually trying to solve a 3D traction problem and I would like to use mpirun.

However the following error occurs whenever I try to :
Primary job terminated normally, but 1 process returned a non-zero exit code. Per user-direction, the job has been aborted.
mpirun noticed that process rank 2 with PID 0 on node rep-calcul1 exited on signal 11 (Segmentation fault).

Here is the code I am currently using :

Please post your code as plain-text, using 3x` encapsulation to ensure correct formatting.
This would make it possible for other user to run and reproduce your error.

Please also post which version of dolfin you are using.