[Pkg-libvirt-maintainers] Bug#924035: libvirt-daemon: Unable to complete lxc guest shutdown: Failed to delete veth device

[Matthew Gabeler-Lee]

Package: libvirt-daemon
Version: 5.0.0-1
Severity: normal

Dear Maintainer,

Since a recent upgrade (I _think_ this showed up when libvirt 5.0 migrated
to buster, but I'm not entirely sure of that.  It could also be related to
the 4.20 kernel, which is the minimum version needed to support the onboard
graphics in my coffee lake system), I can no longer fully shut down lxc
guests.  I can't trigger a guest shutdown externally, but that is not the
bug I'm reporting here.  If I trigger the guest shutdown from within the
guest, the guests shuts down, and the parent libvirt_lxc process exits, but
the libvirt daemon then hits an error, which is logged thus:

2019-03-08 16:14:00.548+0000: 17612: error : virNetDevVethDelete:210 : internal error: Failed to delete veth device vnet3

(the vnet device number of course changes over time / guest)

At this point I can neither force shut down the guest, nor can I restart it. 
My ownly recourse is to restart the libvirt daemon (reload is insufficient). 
A restart _does_ work, but it disconnects all clients, and I've had bad
experiences in the past with such actions putting libvirt / guests into a
bad state, e.g.  having two copies of every lxc guest running, one of which
has become completely dissociated from the libvirt daemon, with chaotic and
deleterious effect.

Note: this does _not_ affect qemu guests.

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'testing-debug'), (500, 'stable'), (500, 'oldstable'), (490, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.20.0-trunk-amd64 (SMP w/16 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages libvirt-daemon depends on:
ii  libacl1             2.2.52-5
ii  libapparmor1        2.13.2-7
ii  libaudit1           1:2.8.4-2
ii  libavahi-client3    0.7-4+b1
ii  libavahi-common3    0.7-4+b1
ii  libblkid1           2.33.1-0.1
ii  libc6               2.28-7
ii  libcap-ng0          0.7.9-2
ii  libcurl3-gnutls     7.64.0-1
ii  libdbus-1-3         1.12.12-1
ii  libdevmapper1.02.1  2:1.02.155-2
ii  libfuse2            2.9.9-1
ii  libgcc1             1:8.2.0-21
ii  libgnutls30         3.6.6-2
ii  libnetcf1           1:0.2.8-1+b2
ii  libnl-3-200         3.4.0-1
ii  libnl-route-3-200   3.4.0-1
ii  libnuma1            2.0.12-1
ii  libparted2          3.2-24
ii  libpcap0.8          1.8.1-6
ii  libpciaccess0       0.14-1
ii  libsasl2-2          2.1.27+dfsg-1
ii  libselinux1         2.8-1+b1
ii  libssh2-1           1.8.0-2
ii  libudev1            240-6
ii  libvirt0            5.0.0-1
ii  libxenmisc4.11      4.11.1-1
ii  libxenstore3.0      4.11.1-1
ii  libxentoollog1      4.11.1-1
ii  libxml2             2.9.4+dfsg1-7+b3
ii  libyajl2            2.1.0-3

Versions of packages libvirt-daemon recommends:
ii  libxml2-utils   2.9.4+dfsg1-7+b3
ii  netcat-openbsd  1.195-2
ii  qemu            1:3.1+dfsg-4
ii  qemu-kvm        1:3.1+dfsg-4

Versions of packages libvirt-daemon suggests:
pn  libvirt-daemon-driver-storage-gluster  <none>
pn  libvirt-daemon-driver-storage-rbd      <none>
pn  libvirt-daemon-driver-storage-zfs      <none>
ii  libvirt-daemon-system                  5.0.0-1
pn  numad                                  <none>

-- no debconf information