Lubuntu 18.04 is based on LXDE, not LXQt, and so it uses lightdm, not sddm. greeter is lightdm-gtk-greeter, which causes traps in libglib like these :
ноя 04 16:50:48 user-desktop kernel: traps: lightdm-gtk-gre[673] trap int3 ip:b6f929d0 sp:bf9e9e20 error:0 in libglib-2.0.so.0.5600.4[b6f44000+12e000] ноя 04 16:50:52 user-desktop kernel: traps: lightdm-gtk-gre[736] trap int3 ip:b6fe49d0 sp:bfbcfcd0 error:0 in libglib-2.0.so.0.5600.4[b6f96000+12e000] ноя 04 16:50:54 user-desktop kernel: traps: lightdm-gtk-gre[798] trap int3 ip:b70149d0 sp:bf839010 error:0 in libglib-2.0.so.0.5600.4[b6fc6000+12e000] ноя 04 16:50:56 user-desktop kernel: traps: lightdm-gtk-gre[860] trap int3 ip:b70669d0 sp:bf9a2f40 error:0 in libglib-2.0.so.0.5600.4[b7018000+12e000] ноя 04 16:50:57 user-desktop kernel: traps: lightdm-gtk-gre[922] trap int3 ip:b701a9d0 sp:bfe9c750 error:0 in libglib-2.0.so.0.5600.4[b6fcc000+12e000] ноя 04 16:50:59 user-desktop kernel: traps: lightdm-gtk-gre[984] trap int3 ip:b6fa19d0 sp:bfb4dcb0 error:0 in libglib-2.0.so.0.5600.4[b6f53000+12e000] -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1902871 Title: upgrading systemd to v237-3ubuntu10.43 on Ubuntu 18.04 LTS i386 causes lightdm to crash Status in systemd package in Ubuntu: Incomplete Bug description: Reproduction : take a bog-standard system with Intel CPU and Intel graphics (mobo like Foxconn 45GM/45CM/45CM-S or ECS 945GCT-M2 with Intel E4500, or ASRock G41C-VS/G41M-VS3/G31M-S with Intel E3300/E3400, or Asrock P4I45GL with Intel Pentium4 2.40GHz) ; install Lubuntu 18.04 i386 on it ; install all latest upgrades including systemd packages of version 237-3ubuntu10.43 ; reboot and watch black screen with blinking text cursor Fix : switch into text console or log in as sudo-capable user over the network look at lightdm crashes in dmesg download past version of systemd packages (237-3ubuntu10.42) install them by dpkg reboot and enjoy your graphic screen again To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1902871/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
