Periodically, I find that my Linux virtual machine disappears when I log into a user's X session within it. The virtual machine starts up fine and gets to the graphical login (lightdm) fine. Once the user's password is supplied, the virtual machine either completely crashes and disappears or successfully logs in and is stable.
From what I've found, each time it crashes and disappears, there's an entry in dmesg similar to:
[676539.325339] kvm-spice[15142]: segfault at 20 ip 00007fdcaff0b986 sp 00007fffc5c46870 error 4 in libspice-server.so.1.5.0[7fdcafec6000+10f000]
ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: qemu-kvm-spice 1.2.0-2012.09-0ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-18.29-generic 3.5.7
Uname: Linux 3.5.0-18-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
Date: Tue Nov 13 10:40:28 2012
InstallationDate: Installed on 2009-12-21 (1057 days ago)
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
MarkForUpload: True
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: qemu-linaro
UpgradeStatus: Upgraded to quantal on 2012-10-12 (32 days ago)
---
ApportVersion: 2.14.1-0ubuntu3.3
Architecture: amd64
CurrentDesktop: xubuntu
DistroRelease: Ubuntu 14.04
InstallationDate: Installed on 2009-12-21 (1721 days ago)
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
NonfreeKernelModules: nvidia
Package: libspice-server1 0.12.5-1 [origin: unknown]
PackageArchitecture: amd64
Tags: trusty third-party-packages
Uname: Linux 3.16.1-ar-9a35988 x86_64
UnreportableReason: This is not an official Ubuntu package. Please remove any third party package and try again.
UpgradeStatus: Upgraded to trusty on 2014-04-17 (143 days ago)
UserGroups: adm admin cdrom dialout libvirtd lpadmin plugdev sambashare
_MarkForUpload: True
Still seeing similar crashes under 14.04:
[450016.317236] qemu-system-