Xorg crashed with SIGSEGV in _nv001646X()

Restarting a guess operating system on VirtualBox (a normal operation), then session was closed. Probably not related to VirtualBox but related with display drivers (nvidia).

Backtrace:
0: /usr/bin/X(xorg_backtrace+0x26) [0x4f00c6]
1: /usr/bin/X(xf86SigHandler+0x41) [0x4852c1]
2: /lib/libc.so.6 [0x7f7ba50ec530]
3: /usr/lib/xorg/modules/drivers//nvidia_drv.so(_nv001646X+0x26) [0x7f7ba2537856]
4: /usr/lib/xorg/modules/drivers//nvidia_drv.so(_nv001415X+0x64) [0x7f7ba254be04]
5: /usr/lib/xorg/modules/drivers//nvidia_drv.so [0x7f7ba27d9904]
6: /usr/lib/xorg/modules/drivers//nvidia_drv.so [0x7f7ba27ef74d]
7: /usr/lib/xorg/modules/drivers//nvidia_drv.so [0x7f7ba27f291e]
8: /usr/lib/xorg/modules/drivers//nvidia_drv.so [0x7f7ba27f2e9c]
9: /usr/lib/xorg/modules/drivers//nvidia_drv.so [0x7f7ba27f343f]
10: /usr/lib/xorg/modules/drivers//nvidia_drv.so [0x7f7ba27b6358]
11: /usr/bin/X [0x535205]
12: /usr/bin/X [0x4ffb96]
13: /usr/bin/X(BlockHandler+0x50) [0x452200]
14: /usr/bin/X(WaitForSomething+0x141) [0x4edbf1]
15: /usr/bin/X(Dispatch+0xb2) [0x44de92]
16: /usr/bin/X(main+0x3b5) [0x434085]
17: /lib/libc.so.6(__libc_start_main+0xfd) [0x7f7ba50d7abd]
18: /usr/bin/X [0x433509]
Saw signal 11. Server aborting.

ProblemType: Crash
Architecture: amd64
Date: Fri Mar 5 12:32:41 2010
DistroRelease: Ubuntu 9.10
ExecutablePath: /usr/bin/Xorg
MachineType: DataLogic GeForce6100PM-M2
NonfreeKernelModules: nvidia
Package: xserver-xorg-core 2:1.6.4-2ubuntu4.1
ProcCmdLine: root=UUID=2d8bc3a4-bc74-4d52-9e5c-cf03a19ededf ro quiet splash
ProcCmdline: /usr/bin/X :0 -br -verbose -auth /var/run/gdm/auth-for-gdm-HjWZ6b/database -nolisten tcp vt7
ProcEnviron:
 LANG=es_ES.UTF-8
 PATH=(custom, no user)
 LANGUAGE=es_ES:es:en_GB:en
ProcVersionSignature: Ubuntu 2.6.31-20.57-generic
RelatedPackageVersions:
 xserver-xorg 1:7.4+3ubuntu10
 libgl1-mesa-glx 7.6.0-1ubuntu4
 libdrm2 2.4.14-1ubuntu1
 xserver-xorg-video-intel 2:2.9.0-1ubuntu2.1
 xserver-xorg-video-ati 1:6.12.99+git20090929.7968e1fb-0ubuntu1
SegvAnalysis:
 Segfault happened at: 0x7f7ba2537856 <_nv001646X+38>: mov 0x0(%rbp),%rbx
 PC (0x7f7ba2537856) ok
 source "0x0(%rbp)" (0x00000000) not located in a known VMA region (needed readable region)!
 destination "%rbx" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: xorg-server
StacktraceTop:
 _nv001646X ()
 _nv001415X ()
 ?? ()
 ?? ()
 ?? ()
Title: Xorg crashed with SIGSEGV in _nv001646X()
Uname: Linux 2.6.31-20-generic x86_64
UserGroups:

dmi.bios.date: 04/03/2008
dmi.bios.vendor: Phoenix Technologies, LTD
dmi.bios.version: 6.00 PG
dmi.board.name: GeForce6100PM-M2
dmi.board.vendor: ECS
dmi.board.version: 2.0
dmi.chassis.asset.tag: Unknow
dmi.chassis.type: 3
dmi.chassis.vendor: ECS
dmi.chassis.version: Unknow
dmi.modalias: dmi:bvnPhoenixTechnologies,LTD:bvr6.00PG:bd04/03/2008:svnDataLogic:pnGeForce6100PM-M2:pvr2.0:rvnECS:rnGeForce6100PM-M2:rvr2.0:cvnECS:ct3:cvrUnknow:
dmi.product.name: GeForce6100PM-M2
dmi.product.version: 2.0
dmi.sys.vendor: DataLogic
fglrx: Not loaded
system:
 distro: Ubuntu
 architecture: x86_64kernel: 2.6.31-20-generic