Comment 4 for bug 1297383

Pekka, can you try and get a backtrace?

First install -dbg packages for cogl, gjs, gnome-shell libglib

Switch to a VT (or login with ssh from another computer) then run

sudo gdb attach -pid `pidof gnome-shell`
b _cogl_set_error
c

Now go back to you gnome-shell session and try to switch users

finally back to the VT and type into gdb the following:
set logging file cogl.log
set logging on
t a a bt
set logging off