I am seeing the same issue from my upgrade. I don't think the entry for Server in the Socket section is the cause.
ar 15 15:32:56 jket-deb systemd[1]: Reloading. Mar 15 15:32:56 jket-deb systemd[1]: /lib/systemd/system/virtlockd-admin.socket:7: Unknown lvalue 'Server' in section 'Socket' Mar 15 15:32:56 jket-deb systemd[1]: Reloading. Mar 15 15:32:56 jket-deb audit[29849]: AVC apparmor="DENIED" operation="signal" profile="/usr/sbin/libvirtd" pid=29849 comm="libvirtd" requested_mask="send" denied_mask="send" signal=hup pee Mar 15 15:32:56 jket-deb audit[29849]: AVC apparmor="DENIED" operation="signal" profile="/usr/sbin/libvirtd" pid=29849 comm="libvirtd" requested_mask="send" denied_mask="send" signal=hup pee Mar 15 15:32:56 jket-deb audit[29849]: AVC apparmor="DENIED" operation="signal" profile="/usr/sbin/libvirtd" pid=29849 comm="libvirtd" requested_mask="send" denied_mask="send" signal=hup pee Mar 15 15:32:56 jket-deb kernel: audit: type=1400 audit(1521149576.914:41): apparmor="DENIED" operation="signal" profile="/usr/sbin/libvirtd" pid=29849 comm="libvirtd" requested_mask="send" Mar 15 15:32:56 jket-deb kernel: audit: type=1400 audit(1521149576.914:42): apparmor="DENIED" operation="signal" profile="/usr/sbin/libvirtd" pid=29849 comm="libvirtd" requested_mask="send" Mar 15 15:32:56 jket-deb kernel: audit: type=1400 audit(1521149576.914:43): apparmor="DENIED" operation="signal" profile="/usr/sbin/libvirtd" pid=29849 comm="libvirtd" requested_mask="send" Mar 15 15:32:56 jket-deb systemd[1]: /lib/systemd/system/virtlockd-admin.socket:7: Unknown lvalue 'Server' in section 'Socket' Mar 15 15:32:56 jket-deb systemd[1]: virtlogd-admin.socket: Socket service virtlogd.service already active, refusing. Mar 15 15:32:56 jket-deb systemd[1]: Failed to listen on Virtual machine log manager socket. -- Subject: Unit virtlogd-admin.socket has failed -- Defined-By: systemd -- Support: https://www.debian.org/support -- -- Unit virtlogd-admin.socket has failed. -- -- The result is RESULT. Mar 15 15:32:56 jket-deb systemd[1]: Dependency failed for Virtual machine log manager. -- Subject: Unit virtlogd.service has failed -- Defined-By: systemd -- Support: https://www.debian.org/support -- -- Unit virtlogd.service has failed. -- -- The result is RESULT. Mar 15 15:32:56 jket-deb systemd[1]: virtlogd.service: Job virtlogd.service/start failed with result 'dependency'. Mar 15 15:32:57 jket-deb sudo[29716]: pam_unix(sudo:session): session closed for user root Mar 15 15:32:59 jket-deb sudo[30326]: jket : TTY=pts/6 ; PWD=/home/jket ; USER=root ; COMMAND=/bin/journalctl -xe Mar 15 15:32:59 jket-deb sudo[30326]: pam_unix(sudo:session): session opened for user root by (uid=0)
