Comment 5 for bug 1364173

I found out that kdm runs /etc/kde4/kdm/Xsession using user's default shell.
http://i.imgur.com/xyiJ1b8.jpg

It is not sane as in Xsession(5) manpage notes:
/etc/X11/Xsession is a Bourne shell (sh(1)) script which is run when an X Window System session is begun by startx(1) or a display manager such as xdm(1).