Comment 18 for bug 1291574

I can trigger the bug with docky anytime I want. Just move quickly through Docky icons with the mouse cursor (https://bugs.launchpad.net/ubuntu/+source/docky/+bug/1451379). I a few seconds the screen will freeze. Most of the times I have to wait for about 30 seconds. I can switch to text (Alt + Ctrl + F1) in the meantime and see that gnome-shell occupies the computer 100%. Nouveau driver writes lots of lines into syslog at the same time. But sometimes everything freezes and only hard reset helps.

It starts like that:
May 21 08:35:37 computer gnome-session[8979]: nouveau: kernel rejected pushbuf: Invalid argument
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: krec 0 pushes 1 bufs 19 relocs 0
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000000 00000005 00000004 00000004 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000001 000001b9 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000002 00000007 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000003 0000000a 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000004 0000000b 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000005 00000008 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000006 00000006 00000004 00000000 00000004
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000007 0000019e 00000002 00000000 00000002
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000008 00000013 00000002 00000000 00000002
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000009 0000000d 00000004 00000004 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 0000000a 00000104 00000004 00000004 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 0000000b 00000124 00000002 00000002 00000002
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 0000000c 00000026 00000004 00000004 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 0000000d 00000090 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 0000000e 000001b1 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 0000000f 000001ac 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000010 000001ad 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000011 00000030 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: buf 00000012 000001ba 00000002 00000002 00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: ch0: psh 00000000 000005e7d4 000006045c
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x0004721c
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x0fac6881
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00086ff4
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x12c00000
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x04b00000
May 21 08:35:37 computer kernel: [263094.549645] nouveau E[gnome-shell[9087]] multiple instances of buffer 442 on validation list
May 21 08:35:37 computer kernel: [263094.549650] nouveau E[gnome-shell[9087]] validate_init
May 21 08:35:37 computer kernel: [263094.549652] nouveau E[gnome-shell[9087]] validate: -22
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00146200
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x511f0000
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x000000e6
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00000040
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00087240
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x000012c0
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x000004b0
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00047224
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00000001
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00146fe0
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x42dd0000
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00000016
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00000040
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00000000
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00047538
May 21 08:35:37 computer gnome-session[8979]: nouveau: #0110x00000001

And then hundreds of these lines with "nouveau: #..."