Xorg crashed with SIGABRT in __GI___libc_free() from xf86CursorUnrealizeCursor()

[Alexandr Novel]

For some reason easily triggered by Firefox 31 to 33.
Chromium and other graphical applications work without problems.

Firefox 28 from the live Ubuntu 14.04 usb drive, does not trigger Xorg crash.

The crashes occur with the stock Xorg as well as Xorg-edgers.

One of the previous crashes was slightly different.

sudo gdb /usr/bin/Xorg /etc/X11/core

Reading symbols from /usr/bin/Xorg...Reading symbols from /usr/lib/debug//usr/bin/Xorg...done.
done.
[New LWP 8247]
[New LWP 8248]
[New LWP 8246]

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt'.
Program terminated with signal SIGBUS, Bus error.
#0 memset () at ../sysdeps/x86_64/memset.S:114
114 ../sysdeps/x86_64/memset.S: No such file or directory.
(gdb) bt
#0 memset () at ../sysdeps/x86_64/memset.S:114
#1 0x00007f6ca68cd306 in ?? () from /usr/lib/xorg/modules/drivers/intel_drv.so
#2 0x0000000000000000 in ?? ()

ProblemType: Crash
DistroRelease: Ubuntu 14.04
Package: xserver-xorg-core 2:1.15.1-0ubuntu2.1
ProcVersionSignature: Ubuntu 3.5.0-18.29-generic 3.5.7
Uname: Linux 3.5.0-18-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.14.1-0ubuntu3.5
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
CrashCounter: 1
Date: Fri Oct 17 13:57:51 2014
DistUpgraded: 2014-08-19 14:00:57,964 DEBUG enabling apt cron job
DistroCodename: trusty
DistroVariant: ubuntu
ExecutablePath: /usr/bin/Xorg
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller [8086:2a42] (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Lenovo Device [17aa:20e4]
   Subsystem: Lenovo Device [17aa:20e4]
InstallationDate: Installed on 2012-06-22 (847 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MachineType: LENOVO 647341U
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcCmdline: /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
ProcEnviron:

ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-18-generic root=UUID=cc4e5011-50ff-4db4-856e-d1ef85ab4327 ro crashkernel=384M-:128M
Signal: 6
SourcePackage: xorg-server
StacktraceTop:
 __GI___libc_free (mem=0xffffffffffffffff) at malloc.c:2929
 xf86CursorUnrealizeCursor (pDev=0x0, pScreen=0x7fdb1a212b70, pCurs=0x7fdb1a534a90) at ../../../../hw/xfree86/ramdac/xf86Cursor.c:294
 AnimCurUnrealizeCursor (pDev=<optimized out>, pScreen=0x7fdb1a212b70, pCursor=<optimized out>) at ../../render/animcur.c:282
 FreeCursor (value=0x7fdb1a534a90, cid=<optimized out>) at ../../dix/cursor.c:124
 ?? () from /usr/lib/xorg/modules/drivers/intel_drv.so
Title: Xorg crashed with SIGABRT in __GI___libc_free()
UpgradeStatus: Upgraded to trusty on 2014-08-19 (58 days ago)
UserGroups:

dmi.bios.date: 10/10/2012
dmi.bios.vendor: LENOVO
dmi.bios.version: 7VET95WW (3.25 )
dmi.board.name: 647341U
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr7VET95WW(3.25):bd10/10/2012:svnLENOVO:pn647341U:pvrThinkPadT400:rvnLENOVO:rn647341U:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 647341U
dmi.product.version: ThinkPad T400
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.11.2+14.04.20140714-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.58+git20141006.00847fa4-0ubuntu0ricotz~trusty
version.libgl1-mesa-dri: libgl1-mesa-dri 10.4.0~git20141017.9ebfb301-0ubuntu0ricotz~trusty
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.4.0~git20141017.9ebfb301-0ubuntu0ricotz~trusty
version.xserver-xorg-core: xserver-xorg-core 2:1.15.1-0ubuntu2.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.8.2-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.916+git20141016.6b98f162-0ubuntu0sarvatt~trusty
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A
xserver.bootTime: Fri Oct 17 13:57:57 2014
xserver.configfile: default
xserver.errors:
 intel: Failed to load module "dri3" (module does not exist, 0)
 intel: Failed to load module "present" (module does not exist, 0)
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 16437
 vendor LEN
xserver.version: 2:1.15.1-0ubuntu2.1

[Apport retracing service (apport)]

StacktraceTop:
 __GI___libc_free (mem=0xffffffffffffffff) at malloc.c:2929
 xf86CursorUnrealizeCursor (pDev=0x0, pScreen=0x7fdb1a212b70, pCurs=0x7fdb1a534a90) at ../../../../hw/xfree86/ramdac/xf86Cursor.c:294
 AnimCurUnrealizeCursor (pDev=<optimized out>, pScreen=0x7fdb1a212b70, pCursor=<optimized out>) at ../../render/animcur.c:282
 FreeCursor (value=0x7fdb1a534a90, cid=<optimized out>) at ../../dix/cursor.c:124
 _sna_blt_fill_boxes (nbox=439776512, box=<optimized out>, blt=0x7fdb1a9e32b0, sna=0x257) at ../../../src/sna/sna_blt.c:1041

[Alexandr Novel (normalex)]

The succesfull workaround for Xorg crashing on Intel GM45 integrated graphics on Lenovo T400 was to create the the following file

/usr/share/X11/xorg.conf.d/20-intel-gm45.conf

Section "Device"
    Identifier "Intel Graphics"
    Driver "intel"
    Option "AccelMethod" "uxa"
EndSection

Swtiching from SNA to UXA alleviated all the problems.

As a side note, gtkperf tool is very reliable to reproduce SNA Xorg crashes.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.