Whenever I go to open my installation of Mathematica, be it from the menu or command line, my screen immediately goes black and I am shown the system login screen -- a complete user logout. Everything worked fine two days ago when I used it last. I suspect this is most likely a system (Debian Testing/Jessie) issue rather than a Mathematica issue, but I really have very little idea where to begin diagnosing this one.
EDIT: I should add I've been using the 3.2.0-4-amd64 (Stable) kernel. Didn't have a problem until today.