Comment 2 for bug 899890

Backtrace:
[ 343.970] 0: /usr/bin/X (xorg_backtrace+0x26) [0x460566]
[ 343.970] 1: /usr/bin/X (0x400000+0x64b7a) [0x464b7a]
[ 343.970] 2: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7f83899bf000+0x10060) [0x7f83899cf060]
[ 343.970] 3: /usr/lib/xorg/modules/extensions/librecord.so (0x7f838736c000+0x26a8) [0x7f838736e6a8]
[ 343.971] 4: /usr/bin/X (_CallCallbacks+0x34) [0x434264]
[ 343.971] 5: /usr/bin/X (WriteToClient+0x21a) [0x4635aa]
[ 343.971] 6: /usr/lib/xorg/modules/extensions/libdri2.so (ProcDRI2WaitMSCReply+0x52) [0x7f8386d53c62]
[ 343.971] 7: /usr/lib/xorg/modules/extensions/libdri2.so (DRI2WaitMSCComplete+0x53) [0x7f8386d523a3]
[ 343.971] 8: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f8386aff000+0x25fd4) [0x7f8386b24fd4]
[ 343.971] 9: /usr/lib/x86_64-linux-gnu/libdrm.so.2 (drmHandleEvent+0xa3) [0x7f8386f5d3c3]
[ 343.971] 10: /usr/bin/X (WakeupHandler+0x5b) [0x433a6b]
[ 343.971] 11: /usr/bin/X (WaitForSomething+0x1b6) [0x45e016]
[ 343.971] 12: /usr/bin/X (0x400000+0x2f912) [0x42f912]
[ 343.971] 13: /usr/bin/X (0x400000+0x232fe) [0x4232fe]
[ 343.971] 14: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xed) [0x7f83888fb30d]
[ 343.971] 15: /usr/bin/X (0x400000+0x235ed) [0x4235ed]
[ 343.971] Segmentation fault at address 0x7f838247e010
[ 343.972]
Caught signal 11 (Segmentation fault). Server aborting