Xorg crashed with SIGABRT

[skipper]

After a system update many crash messages appear.
Nouveau driver with mir.

ProblemType: Crash
DistroRelease: Ubuntu 13.10
Package: xserver-xorg-core 2:1.14.2.901-2ubuntu4
ProcVersionSignature: Ubuntu 3.11.0-4.9-generic 3.11.0-rc7
Uname: Linux 3.11.0-4-generic x86_64
NonfreeKernelModules: wl
.tmp.unity.support.test.0:

ApportVersion: 2.12.1-0ubuntu3
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
Date: Thu Sep 5 09:53:56 2013
DistUpgraded: 2013-06-24 11:06:01,804 DEBUG enabling apt cron job
DistroCodename: saucy
DistroVariant: ubuntu
ExecutablePath: /usr/bin/Xorg
GraphicsCard:
 NVIDIA Corporation C79 [GeForce 9400M] [10de:0870] (rev b1) (prog-if 00 [VGA controller])
   Subsystem: Apple Inc. Device [106b:00ab]
InstallationDate: Installed on 2012-03-14 (539 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64+mac (20120314)
MachineType: Apple Inc. MacBookAir2,1
MarkForUpload: True
ProcCmdline: /usr/bin/X -core :0 -auth /var/run/lightdm/root/:0 -mir 0 -mirSocket /tmp/mir_socket -nolisten tcp
ProcEnviron:

ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-4-generic root=UUID=a52ff72f-6d44-4e2b-8fd8-7bc426c2568c ro quiet splash
Signal: 6
SourcePackage: xorg-server
StacktraceTop:
 ?? () from /usr/lib/xorg/modules/libexa.so
 ?? () from /usr/lib/xorg/modules/libexa.so
 ?? () from /usr/lib/xorg/modules/libexa.so
 ?? () from /usr/lib/xorg/modules/libexa.so
 ?? () from /usr/lib/xorg/modules/libexa.so
Title: Xorg crashed with SIGABRT
UpgradeStatus: Upgraded to saucy on 2013-06-24 (72 days ago)
UserGroups:

XorgConf:
 Section "Device"
  Identifier "Default Device"
  Option "NoLogo" "True"
 EndSection
dmi.bios.date: 03/05/10
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBA21.88Z.0075.B05.1003051506
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-F42D88C8
dmi.board.vendor: Apple Inc.
dmi.chassis.asset.tag: Asset Tag#
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F42D88C8
dmi.modalias: dmi:bvnAppleInc.:bvrMBA21.88Z.0075.B05.1003051506:bd03/05/10:svnAppleInc.:pnMacBookAir2,1:pvr1.0:rvnAppleInc.:rnMac-F42D88C8:rvr:cvnAppleInc.:ct10:cvrMac-F42D88C8:
dmi.product.name: MacBookAir2,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.
version.compiz: compiz 1:0.9.10+13.10.20130828.2-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.46-1
version.libgl1-mesa-dri: libgl1-mesa-dri 9.2-1ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 9.2-1ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.14.2.901-2ubuntu4
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu3.1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.2.0-0ubuntu3
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.21.14-4ubuntu3
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.9-2ubuntu1
xserver.bootTime: Thu Sep 5 10:10:54 2013
xserver.configfile: /etc/X11/xorg.conf
xserver.errors:
 Failed to load module "nvidia" (module does not exist, 0)
 Failed to load module "nvidia" (module does not exist, 0)
 Server terminated successfully (0). Closing log file.
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs: Output XMIR-1
xserver.version: 2:1.14.2.901-2ubuntu4
xserver.video_driver: nouveau

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1033533, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.