[libvirt-users] "virsh list" hangs

[Michal Privoznik]

On 17.02.2017 17:18, Yunchih Chen wrote:
> 
> `virsh list` hangs on my server that hosts a bunch of VMs.
> This might be due to the Debian upgrade I did on Feb 15, which upgrades
> `libvirt` from 2.4.0-1 to 3.0.0-2.
> I have tried restarting libvirtd for a few times, without luck.
> 
> Attached below are some relevant logs; let me know if you need some more
> for debugging.
> Thanks for your help!!
> 
> root at vm-host:~# uname -a
> Linux vm-host 4.6.0-1-amd64 #1 SMP Debian 4.6.4-1 (2016-07-18) x86_64
> GNU/Linux
> 
> root at vm-host:~# apt-cache policy libvirt-daemon
> libvirt-daemon:
>   Installed: 3.0.0-2
>   Candidate: 3.0.0-2
>   Version table:
>  *** 3.0.0-2 500
>         500 http://debian.csie.ntu.edu.tw/debian testing/main amd64
> Packages
>         100 /var/lib/dpkg/status
> 
> root at vm-host:~# strace -o /tmp/trace -e trace=network,file,poll virsh
> list  # hangs forever .....
> ^C
> root at vm-host:~# tail -10 /tmp/trace
> access("/etc/libvirt/libvirt.conf", F_OK) = 0
> open("/etc/libvirt/libvirt.conf", O_RDONLY) = 5
> access("/proc/vz", F_OK)                = -1 ENOENT (No such file or
> directory)
> socket(AF_UNIX, SOCK_STREAM, 0)         = 5
> connect(5, {sa_family=AF_UNIX,
> sun_path="/var/run/libvirt/libvirt-sock"}, 110) = 0
> getsockname(5, {sa_family=AF_UNIX}, [128->2]) = 0
> poll([{fd=5, events=POLLOUT}, {fd=6, events=POLLIN}], 2, -1) = 1
> ([{fd=5, revents=POLLOUT}])
> poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}], 2, -1) = ?
> ERESTART_RESTARTBLOCK (Interrupted by signal)
> --- SIGINT {si_signo=SIGINT, si_code=SI_KERNEL} ---
> +++ killed by SIGINT +++
> 
> root at vm-host:~# lsof /var/run/libvirt/libvirt-sock # hangs too ...

This is very suspicious. Looks like the daemon is in some weird state
and hence virsh is unable to get list of domains.

# ps axf | grep libvirtd
# gdb -p $(pgrep libvirtd)
(gdb) t a a bt

if you could run those commands and share the output that might shed
more light.

Michal