Comment 18 for bug 316566

Ahh, I spoke too soon. Your kernel log does indeed show a problem:

Jan 14 14:57:37 max-work-lap kernel: [ 203.600093] Call Trace:
Jan 14 14:57:37 max-work-lap kernel: [ 203.600106] [<ffffffff802aff35>] oom_kill_process+0x95/0x240
Jan 14 14:57:37 max-work-lap kernel: [ 203.600113] [<ffffffff802b06ef>] ? select_bad_process+0xef/0x130
Jan 14 14:57:37 max-work-lap kernel: [ 203.600120] [<ffffffff802b07e4>] out_of_memory+0xb4/0x150
Jan 14 14:57:37 max-work-lap kernel: [ 203.600129] [<ffffffff804958a0>] ? moom_callback+0x0/0x20
Jan 14 14:57:37 max-work-lap kernel: [ 203.600135] [<ffffffff804958b7>] moom_callback+0x17/0x20
Jan 14 14:57:37 max-work-lap kernel: [ 203.600142] [<ffffffff8026113a>] run_workqueue+0xba/0x190
Jan 14 14:57:37 max-work-lap kernel: [ 203.600148] [<ffffffff80261417>] worker_thread+0xa7/0x120
Jan 14 14:57:37 max-work-lap kernel: [ 203.600155] [<ffffffff80265770>] ? autoremove_wake_function+0x0/0x40
Jan 14 14:57:37 max-work-lap kernel: [ 203.600161] [<ffffffff80261370>] ? worker_thread+0x0/0x120
Jan 14 14:57:37 max-work-lap kernel: [ 203.600167] [<ffffffff80265309>] kthread+0x49/0x90
Jan 14 14:57:37 max-work-lap kernel: [ 203.600174] [<ffffffff80213979>] child_rip+0xa/0x11
Jan 14 14:57:37 max-work-lap kernel: [ 203.600180] [<ffffffff802652c0>] ? kthread+0x0/0x90
Jan 14 14:57:37 max-work-lap kernel: [ 203.600186] [<ffffffff8021396f>] ? child_rip+0x0/0x11

The kernel is calling the "Out of Memory killer", "oom_kill_process". This means that your system has catastrophically run out of memory for some reason. This is not an Xorg bug, so I'm refiling to Ubuntu for better triaging.

Meanwhile, look into why you would be running out of memory. Are you running a program that uses too much memory? Is your hardware memory bad? Do you have enough of it? There are various programs, like 'top', which you can use to display memory usage and watch the memory use of different processes so you can learn which package has the fault.

Good luck!