I think this is/was either a bug in the radeon driver, or a faulty graphics card. (however, it was only triggered when on the lightdm gtk greeter screen). I've replaced my card with another one, and no longer have this issue.
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-screensaver in Ubuntu. https://bugs.launchpad.net/bugs/1543782 Title: Complete system freeze some time after lock screen starts Status in LightDM GTK+ Greeter: New Status in Ubuntu GNOME: New Status in gnome-screensaver package in Ubuntu: Invalid Bug description: Ever since updating to 15.10 my computer has been freezing every day. Usually this happens after I've left work, and since I leave my computer on, I manually start the screensaver (ctrl+alt+L), and when I come back the next morning, the computer is completely unresponsive, even to sysrq. Gnome screensaver itself doesn't appear to be the culprit since I can turn it on, then log back into my system any time within perhaps 5 minutes. Looking at my root journalctrl output, yesterday, it appears to have crashed 30 minutes after I logged out (I was zeroing a drive with dd, and was issuing a kill -USR1 to track the progress every 30 seconds). At first I thought it might be a botched upgrade from 15.04, so I tried a clean reinstall last week, but it still freezes. There is also nothing in the logs that would indicate an error/crash. The only potentially related piece of information is that I use gnome- shell, installed via ubuntu-gnome-desktop. I'm not sure what package to file this under since I don't know how to reproduce, or how to diagnose the issue. Any debugging advice will be appreciated since this issue is really starting to annoy me. ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: gnome-screensaver 3.6.1-7ubuntu1 ProcVersionSignature: Ubuntu 4.2.0-27.32-generic 4.2.8-ckt1 Uname: Linux 4.2.0-27-generic x86_64 ApportVersion: 2.19.1-0ubuntu5 Architecture: amd64 CurrentDesktop: GNOME Date: Tue Feb 9 13:20:44 2016 EcryptfsInUse: Yes GnomeSessionIdleInhibited: No GnomeSessionInhibitors: None GsettingsGnomeSession: org.gnome.desktop.session session-name 'gnome' org.gnome.desktop.session idle-delay uint32 600 InstallationDate: Installed on 2016-02-04 (4 days ago) InstallationMedia: Ubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021) SourcePackage: gnome-screensaver UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/lightdm-gtk-greeter/+bug/1543782/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
