libvirtd crashes immediately after starting when udev_log=debug

[Ivan Nestlerode]

Starting some time in February libvirtd started crashing immediately at startup. This is not in response to running any specific VM; it is just starting up at boot time and crashing. I noticed this when I went to run virt-manager and it said that libvirtd was not running. Attempts to start libvirtd manually also crash. I did not make any specific change to my machine to cause this (it probably got automatic updates from Ubuntu and nothing else).

I don't remember the exact date that this started happening, but my VM images have modification time stamps of February 2, 2012. So it was some time after that.

I tried downgrading python-libvirt, libvirt-bin, and libvirt0 back to 0.9.2-4ubuntu15.1 but this did not fix the problem. This is on a Lenovo ThinkPad W520 if that is important. I will attach libvirtd.log.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: libvirt-bin 0.9.2-4ubuntu15.2
ProcVersionSignature: Ubuntu 3.0.0-17.30-generic 3.0.22
Uname: Linux 3.0.0-17-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Fri Mar 30 02:04:24 2012
ProcEnviron:
 LANGUAGE=
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: libvirt
UpgradeStatus: No upgrade log present (probably fresh install)

[Serge Hallyn (serge-hallyn)]

Hi,

in the log file I see:

22:50:10.419: 6618: error : udev_set_log_fn:336 : custom logging function 0x7fffb6001958 registered

Caught Segmentation violation dumping internal log buffer:

Could you please post your /etc/libvirt/libvirtd.conf file? Could you post the output of 'dpkg -l | grep udev'?

[Ivan Nestlerode (inestlerode)]

I don't think I have ever modified anything in /etc/libvirt/libvirtd.conf. Here it is with comments and blank lines removed:

$ grep -v -E -e '^#' -e '^$' /etc/libvirt/libvirtd.conf
unix_sock_group = "libvirtd"
unix_sock_rw_perms = "0770"
auth_unix_ro = "none"
auth_unix_rw = "none"

Here is the version of udev related packages (minus package comments that caused crazy looking formatting):
$ dpkg -l|grep udev
ii libgudev-1.0-0 1:173-0ubuntu4.2
ii libudev0 173-0ubuntu4.2
ii python-pyudev 0.12-1
ii system-config-printer-udev 1.3.6+20110831-0ubuntu9.4
ii udev 173-0ubuntu4.2

In terms of the fact that this started in February this may have been when I modified my udev configuration (/etc/udev.conf) to turn on debug logging. I haven't filed the bug yet in Launchpad, but I am chasing down what seems to be a bug in udev that makes my machine hang about half of the time when it boots. I was trying to gather information to file that bug report, but maybe I will attempt to undo that if it is related to this libvirtd crash (I have no ability to use any of my VMs currently which is very bad).

Here is /etc/udev.conf:
# The initial syslog(3) priority: "err", "info", "debug" or its
# numerical equivalent. For runtime debugging, the daemons internal
# state can be changed with: "udevadm control --log-priority=<value>".
udev_log="debug"

[Serge Hallyn (serge-hallyn)]

Thanks for that info. Confirmed! When I set udev_log=debug, libvirt crashes immediately, even uptodate upstream git.

Dropping priority to medium because there is a workaround.

[Serge Hallyn (serge-hallyn)]

Seems safe to assume this must be fixed by now, please ping if it is still happening.