Bah, sorry about that. Thanks for taking the time to report this bug and helping to make Ubuntu better. We appreciate the difficulties you are facing, but this appears to be a "regular" (non-security) bug. I have unmarked it as a security issue since this bug does not show evidence of allowing attackers to cross privilege boundaries nor directly cause loss of data/privacy. Please feel free to report any other bugs you may find.
For your specific issue, XorgLogOld.txt contains some repeated messages just before Xorg exits: [ 63467.012] (WW) RADEON(0): flip queue failed: No space left on device [ 63467.012] (WW) RADEON(0): Page flip failed: No space left on device -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1458293 Title: Xorg crash To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1458293/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp