QGIS 2.14 worked fine until a couple of days ago (ubuntu 15.10 wily), but now crashes at startup with only this error :
Segmentation fault (core dumped)
sudo qgis doesn't give any error but QGIS don't start.
qgis --noplugins doesn't help.
QGIS was installed from http://qgis.org/debian.
For development, I installed libqwt6. This might have been the source of the issue, but removal of all qwt packages and QGIS packages didn't help.
sudo qgisshould never be required.