После обновления сизифа 25.10.17 sddm падает, не давая даже запустить консоль.
Проверено на двух машинах.
Пример лога:

Oct 26 13:18:38 example.localdomain systemd[1]: Stopped Light Display Manager.
Oct 26 13:18:38 example.localdomain systemd[1]: Starting Light Display Manager...
Oct 26 13:18:38 example.localdomain systemd[1]: Started Light Display Manager.
Oct 26 13:18:39 example.localdomain sddm-greeter[1818]: QObject: Cannot create children for a parent that is in a different thread.
                                                        (Parent is SDDM::GreeterApp(0x7ffe82b4a310), parent's thread is QThread(0x6b36c0), current thread is QThread(0x7178a0)
Oct 26 13:18:39 example.localdomain sddm-greeter[1818]: QObject: Cannot create children for a parent that is in a different thread.
                                                        (Parent is SDDM::GreeterApp(0x7ffe82b4a310), parent's thread is QThread(0x6b36c0), current thread is QThread(0x7178a0)
Oct 26 13:18:39 example.localdomain sddm-greeter[1818]: QObject: Cannot create children for a parent that is in a different thread.
                                                        (Parent is SDDM::GreeterApp(0x7ffe82b4a310), parent's thread is QThread(0x6b36c0), current thread is QThread(0x7178a0)
Oct 26 13:18:39 example.localdomain sddm-greeter[1818]: QObject: Cannot create children for a parent that is in a different thread.
                                                        (Parent is SDDM::GreeterApp(0x7ffe82b4a310), parent's thread is QThread(0x6b36c0), current thread is QThread(0x7178a0)
Oct 26 13:18:39 example.localdomain sddm-greeter[1818]: QObject::installEventFilter(): Cannot filter events for objects in a different thread.
Oct 26 13:18:39 example.localdomain sddm-greeter[1818]: QObject: Cannot create children for a parent that is in a different thread.
                                                        (Parent is SDDM::GreeterApp(0x7ffe82b4a310), parent's thread is QThread(0x6b36c0), current thread is QThread(0x7178a0)
Oct 26 13:18:40 example.localdomain libvirtd[1454]: 2017-10-26 10:18:40.569+0000: 1614: info : libvirt version: 3.7.0, package: alt1.S1
Oct 26 13:18:40 example.localdomain libvirtd[1454]: 2017-10-26 10:18:40.569+0000: 1614: info : hostname: example.localdomain
Oct 26 13:18:40 example.localdomain libvirtd[1454]: 2017-10-26 10:18:40.569+0000: 1614: warning : virStorageBackendVolOpen:1601 : ignoring dangling symlink '/home/denis/PlayOnLinux's virtual drives'
Oct 26 13:18:40 example.localdomain audit: NETFILTER_CFG table=filter family=2 entries=0
Oct 26 13:18:40 example.localdomain audit[1912]: SYSCALL arch=c000003e syscall=313 success=yes exit=0 a0=0 a1=419d98 a2=0 a3=0 items=0 ppid=400 pid=1912 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="modprobe" exe="/bin/kmod" key=(null)
Oct 26 13:18:40 example.localdomain audit: PROCTITLE proctitle=2F7362696E2F6D6F6470726F6265002D71002D62002D2D0069707461626C655F66696C746572
Oct 26 13:18:40 example.localdomain systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 26 13:18:40 example.localdomain kernel: ip6_tables: (C) 2000-2006 Netfilter Core Team
Oct 26 13:18:40 example.localdomain audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
Oct 26 13:18:40 example.localdomain audit: NETFILTER_CFG table=filter family=10 entries=0
Oct 26 13:18:40 example.localdomain audit[1917]: SYSCALL arch=c000003e syscall=313 success=yes exit=0 a0=0 a1=419d98 a2=0 a3=0 items=0 ppid=400 pid=1917 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="modprobe" exe="/bin/kmod" key=(null)
Oct 26 13:18:40 example.localdomain audit: PROCTITLE proctitle=2F7362696E2F6D6F6470726F6265002D71002D62002D2D006970367461626C655F66696C746572
Oct 26 13:18:40 example.localdomain systemd[1]: lightdm.service: Unit entered failed state.
Oct 26 13:18:40 example.localdomain systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 26 13:18:40 example.localdomain kernel: Ebtables v2.0 registered
Oct 26 13:18:41 example.localdomain systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 26 13:18:41 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:41 example.localdomain audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:41 example.localdomain systemd[1]: Stopped Light Display Manager.
Oct 26 13:18:41 example.localdomain systemd[1]: Starting Light Display Manager...
Oct 26 13:18:41 example.localdomain systemd[1]: Started Light Display Manager.
Oct 26 13:18:41 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:41 example.localdomain acpid[1240]: client 1902[0:0] has disconnected
Oct 26 13:18:41 example.localdomain acpid[1240]: client connected from 1934[0:0]
Oct 26 13:18:41 example.localdomain acpid[1240]: 1 client rule loaded
Oct 26 13:18:41 example.localdomain sddm-greeter[1818]: QObject: Cannot create children for a parent that is in a different thread.
                                                        (Parent is SDDM::GreeterApp(0x7ffe82b4a310), parent's thread is QThread(0x6b36c0), current thread is QThread(0x7178a0)
Oct 26 13:18:41 example.localdomain sddm-greeter[1818]: QObject::installEventFilter(): Cannot filter events for objects in a different thread.
Oct 26 13:18:41 example.localdomain sddm-greeter[1818]: Cannot watch QRC-like path ":/icons/hicolor/index.theme"
Oct 26 13:18:41 example.localdomain dbus[1251]: [system] Activating via systemd: service name='org.freedesktop.UDisks2' unit='udisks2.service'
Oct 26 13:18:41 example.localdomain systemd[1]: Starting Disk Manager...
Oct 26 13:18:42 example.localdomain udisksd[1965]: udisks daemon version 2.7.3 starting
Oct 26 13:18:42 example.localdomain dbus[1251]: [system] Successfully activated service 'org.freedesktop.UDisks2'
Oct 26 13:18:42 example.localdomain systemd[1]: Started Disk Manager.
Oct 26 13:18:42 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=udisks2 comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:42 example.localdomain udisksd[1965]: Acquired the name org.freedesktop.UDisks2 on the system message bus
Oct 26 13:18:42 example.localdomain dbus[1251]: [system] Activating via systemd: service name='org.freedesktop.UPower' unit='upower.service'
Oct 26 13:18:42 example.localdomain systemd[1]: Starting Daemon for power management...
Oct 26 13:18:42 example.localdomain dbus[1251]: [system] Successfully activated service 'org.freedesktop.UPower'
Oct 26 13:18:42 example.localdomain systemd[1]: Started Daemon for power management.
Oct 26 13:18:42 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=upower comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:42 example.localdomain sddm-greeter[1818]: file:///usr/share/sddm/themes/breeze/components/VirtualKeyboard.qml:20:1: module "QtQuick.VirtualKeyboard" is not installed
Oct 26 13:18:43 example.localdomain sddm-greeter[1818]: QDBusConnection: name 'org.freedesktop.UDisks2' had owner '' but we thought it was ':1.18'
Oct 26 13:18:43 example.localdomain systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 26 13:18:43 example.localdomain audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
Oct 26 13:18:43 example.localdomain systemd[1]: lightdm.service: Unit entered failed state.
Oct 26 13:18:43 example.localdomain systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 26 13:18:43 example.localdomain systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 26 13:18:43 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:43 example.localdomain audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:43 example.localdomain systemd[1]: Stopped Light Display Manager.
Oct 26 13:18:43 example.localdomain systemd[1]: Starting Light Display Manager...
Oct 26 13:18:43 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:43 example.localdomain systemd[1]: Started Light Display Manager.
Oct 26 13:18:43 example.localdomain acpid[1240]: client 1934[0:0] has disconnected
Oct 26 13:18:43 example.localdomain acpid[1240]: client connected from 1997[0:0]
Oct 26 13:18:43 example.localdomain acpid[1240]: 1 client rule loaded
Oct 26 13:18:45 example.localdomain systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 26 13:18:45 example.localdomain audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
Oct 26 13:18:45 example.localdomain systemd[1]: lightdm.service: Unit entered failed state.
Oct 26 13:18:45 example.localdomain systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 26 13:18:46 example.localdomain systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 26 13:18:46 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:46 example.localdomain audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:46 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:46 example.localdomain systemd[1]: Stopped Light Display Manager.
Oct 26 13:18:46 example.localdomain acpid[1240]: client 1997[0:0] has disconnected
Oct 26 13:18:46 example.localdomain systemd[1]: Starting Light Display Manager...
Oct 26 13:18:46 example.localdomain acpid[1240]: client connected from 2006[0:0]
Oct 26 13:18:46 example.localdomain systemd[1]: Started Light Display Manager.
Oct 26 13:18:46 example.localdomain acpid[1240]: 1 client rule loaded
Oct 26 13:18:48 example.localdomain systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 26 13:18:48 example.localdomain audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
Oct 26 13:18:48 example.localdomain systemd[1]: lightdm.service: Unit entered failed state.
Oct 26 13:18:48 example.localdomain systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 26 13:18:48 example.localdomain systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 26 13:18:48 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:48 example.localdomain audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:48 example.localdomain systemd[1]: Stopped Light Display Manager.
Oct 26 13:18:48 example.localdomain systemd[1]: Starting Light Display Manager...
Oct 26 13:18:48 example.localdomain audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=lightdm comm="systemd" exe="/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Oct 26 13:18:48 example.localdomain systemd[1]: Started Light Display Manager.