[Pkg-libvirt-maintainers] Bug#1072769: libvirt-daemon: Cannot connect to hypervisor with user session after upgrade

[Simon John]

Package: libvirt-daemon
Version: 10.4.0-1
Severity: important

Dear Maintainer,

I just did a Sid dist-upgrade and apart from a bunch of t64 packages, it 
upgraded libvirt-daemon (etc) to 10.4.0-1

Then I could no longer connect to qemu://session from virt-manager or 
virsh, I got the errors:

         error: failed to connect to the hypervisor

         virsh error: Cannot recv data: Connection reset by peer

In journalctl I was also seeing this:

         internal error: could not find a usable firewall backend

         Initialization of bridge state driver failed: internal error: 
could not find a usable firewall backend

I use nftables (not firewalld). I tried installing firewalld, restarting 
libvirtd and rebooting all to no avail.

Strangely enough I could run "virsh -c qemu:///system list" as my 
regular user although I got no output (I have no system VM's) it didn't 
error, so I assume its a permissions change or simply a bug in 10.4?

Downgrading to 10.3.0-3 versions of these packages fixed the issue:

         libvirt0_10.3.0-3_amd64.deb
         libvirt-clients_10.3.0-3_amd64.deb
         libvirt-daemon_10.3.0-3_amd64.deb
         libvirt-daemon-config-network_10.3.0-3_all.deb
         libvirt-daemon-config-nwfilter_10.3.0-3_all.deb
         libvirt-daemon-driver-lxc_10.3.0-3_amd64.deb
         libvirt-daemon-driver-qemu_10.3.0-3_amd64.deb
         libvirt-daemon-driver-vbox_10.3.0-3_amd64.deb
         libvirt-daemon-system_10.3.0-3_amd64.deb
         libvirt-daemon-system-systemd_10.3.0-3_all.deb
         libvirt-l10n_10.3.0-3_all.deb
         libvirt-login-shell_10.3.0-3_amd64.deb
         python3-libvirt_10.3.0-1_amd64.deb

I also tried 10.0.0-2 and that seemed to fix it too (didn't try "virsh 
start" but "virsh list" worked) which I think was the version I was on 
beforehand, or 9.x

I dug around for hours trying to find a useful error message or pointer 
to a reason (logs, strace, config etc.) but found nothing, any ideas?

Regards.

-- 
Simon John