netbsd-6: Xorg crash

[Aleksey Cheusov <cheusov%tut.by@localhost>]

Any ideas why the following may happen?
Unfortunately I don't have a debugging info.

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#0  0xbb8ee0d7 in _lwp_kill () from /usr/lib/libc.so.12
#1  0xbb8ee093 in raise () from /usr/lib/libc.so.12
#2  0xbb8ed87d in abort () from /usr/lib/libc.so.12
#3  0x0819a36e in OsAbort ()
#4  0x08193fcf in FatalError ()
#5  0x0819aba2 in ?? ()
#6  <signal handler called>
#7  0xbb47b5df in I830EmitFlush () from
/usr/X11R7/lib/modules/drivers/intel_drv.so
#8  0xbb47b6f0 in I830Sync () from /usr/X11R7/lib/modules/drivers/intel_drv.so
#9  0xbb4729a9 in ?? () from /usr/X11R7/lib/modules/drivers/intel_drv.so
#10 0x080acec6 in ?? ()
#11 0x080a6aa0 in AbortDDX ()
#12 0x08193f17 in AbortServer ()
#13 0x08193ffb in FatalError ()
#14 0xbb46a65e in i830_bind_all_memory ()
   from /usr/X11R7/lib/modules/drivers/intel_drv.so
#15 0xbb472eb2 in ?? () from /usr/X11R7/lib/modules/drivers/intel_drv.so
#16 0x080dcf80 in ?? ()
#17 0x080acc6d in ?? ()
#18 0x080b3a2a in xf86Wakeup ()
#19 0x080a5e69 in WakeupHandler ()
#20 0x0819fe0b in WaitForSomething ()
#21 0x08095091 in Dispatch ()
#22 0x0806f1aa in main ()
------------------------------------------------------------
i915drm0 at vga1: Intel i945G
i915drm0: AGP at 0xd0000000 256MB
i915drm0: Initialized i915 1.6.0 20080730
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