boot failed after run pacman -Syu, text likes “start lightdm failed” on screen.
journalctl -r -g lightdm:
Jul 29 19:41:21 r-lc systemd[1]: lightdm.service: Failed with result 'exit-code'.
Jul 29 19:41:21 r-lc systemd[1]: lightdm.service: Start request repeated too quickly.
Jul 29 19:41:21 r-lc audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=lightdm comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Jul 29 19:41:21 r-lc audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=lightdm comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Jul 29 19:41:21 r-lc systemd[1]: lightdm.service: Scheduled restart job, restart counter is at 5.
Jul 29 19:41:21 r-lc audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=lightdm comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=failed'
Jul 29 19:41:21 r-lc systemd[1]: lightdm.service: Failed with result 'exit-code'.
Jul 29 19:41:21 r-lc systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Jul 29 19:41:21 r-lc audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=lightdm comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Jul 29 19:41:21 r-lc audit[1]: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=lightdm comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Jul 29 19:41:21 r-lc audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 subj==unconfined msg='unit=lightdm comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
...
tac /var/log/pacman.log|grep 'upgraded'|less:
[2021-07-29T16:22:35+0800] [ALPM] upgraded systemd-sysvcompat (248.5-1 -> 248.6-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded snapd (2.51.3-1 -> 2.51.3-2)
[2021-07-29T16:22:35+0800] [ALPM] upgraded squashfs-tools (4.4_git.1-1 -> 4.5-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded qbs (1.19.1-1 -> 1.19.2-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded python-tomli (1.0.4-1 -> 1.1.0-2)
[2021-07-29T16:22:35+0800] [ALPM] upgraded python-sphinx (4.1.1-1 -> 4.1.2-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded python-pyhamcrest (1.10.0-1 -> 1.10.1-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded python-dotenv (0.18.0-1 -> 0.19.0-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded pacman-mirrors (4.21.3-2 -> 4.21.5-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded npm (7.17.0-1 -> 7.20.2-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded nemo-share (5.0.0-10 -> 5.0.0-11)
[2021-07-29T16:22:35+0800] [ALPM] upgraded nemo-python (5.0.0-10 -> 5.0.0-11)
[2021-07-29T16:22:35+0800] [ALPM] upgraded nemo-preview (5.0.0-10 -> 5.0.0-11)
[2021-07-29T16:22:35+0800] [ALPM] upgraded nemo-fileroller (5.0.0-10 -> 5.0.0-11)
[2021-07-29T16:22:35+0800] [ALPM] upgraded modemmanager (1.16.6-1 -> 1.16.8-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded mhwd-db (0.6.5-10 -> 0.6.5-14)
[2021-07-29T16:22:35+0800] [ALPM] upgraded manjaro-release (21.1.0rc2-1 -> 21.1.0rc3-1)
[2021-07-29T16:22:35+0800] [ALPM] upgraded man-pages (5.12-1 -> 5.12-2)
[2021-07-29T16:22:29+0800] [ALPM] upgraded linux54-virtualbox-host-modules (6.1.24-1 -> 6.1.24-2)
[2021-07-29T16:22:23+0800] [ALPM] upgraded linux54-r8168 (8.049.02-5 -> 8.049.02-6)
[2021-07-29T16:22:23+0800] [ALPM] upgraded linux54-headers (5.4.134-1 -> 5.4.135-1)
[2021-07-29T16:22:19+0800] [ALPM] upgraded linux54 (5.4.134-1 -> 5.4.135-1)
[2021-07-29T16:22:12+0800] [ALPM] upgraded linux510-virtualbox-host-modules (6.1.24-1 -> 6.1.24-2)
[2021-07-29T16:22:07+0800] [ALPM] upgraded linux510-r8168 (8.049.02-5 -> 8.049.02-6)
[2021-07-29T16:22:07+0800] [ALPM] upgraded linux510-headers (5.10.52-1 -> 5.10.53-1)
[2021-07-29T16:22:02+0800] [ALPM] upgraded linux510 (5.10.52-1 -> 5.10.53-1)
[2021-07-29T16:22:01+0800] [ALPM] upgraded libreoffice-fresh-zh-cn (7.1.4-1 -> 7.1.5-1)
[2021-07-29T16:22:01+0800] [ALPM] upgraded libreoffice-fresh (7.1.4-1 -> 7.1.5-1)
[2021-07-29T16:22:00+0800] [ALPM] upgraded lib32-tdb (1.4.4-1 -> 1.4.5-1)
[2021-07-29T16:22:00+0800] [ALPM] upgraded lib32-systemd (248.5-1 -> 248.6-1)
[2021-07-29T16:22:00+0800] [ALPM] upgraded lib32-libxfixes (5.0.3-2 -> 6.0.0-1)
[2021-07-29T16:22:00+0800] [ALPM] upgraded lib32-gdk-pixbuf2 (2.42.6-1 -> 2.42.6-2)
[2021-07-29T16:22:00+0800] [ALPM] upgraded lib32-util-linux (2.37-1 -> 2.37.1-1)
[2021-07-29T16:22:00+0800] [ALPM] upgraded lib32-curl (7.77.0-1 -> 7.78.0-1)
[2021-07-29T16:22:00+0800] [ALPM] upgraded jre-openjdk (16.0.1.u9-1 -> 16.0.2.u7-1)
[2021-07-29T16:22:00+0800] [ALPM] upgraded jre-openjdk-headless (16.0.1.u9-1 -> 16.0.2.u7-1)
[2021-07-29T16:21:59+0800] [ALPM] upgraded graphviz (2.48.0-1 -> 2.48.0-2)
[2021-07-29T16:21:59+0800] [ALPM] upgraded libidn (1.37-1 -> 1.38-1)
[2021-07-29T16:21:59+0800] [ALPM] upgraded gnome-desktop (1:40.2-1 -> 1:40.3-1)
[2021-07-29T16:21:59+0800] [ALPM] upgraded geoip-database (20210622-1 -> 20210727-1)
[2021-07-29T16:21:59+0800] [ALPM] upgraded gegl (0.4.30-4 -> 0.4.30-5)
[2021-07-29T16:21:59+0800] [ALPM] upgraded poppler-glib (21.07.0-1 -> 21.07.0-3)
[2021-07-29T16:21:59+0800] [ALPM] upgraded poppler (21.07.0-1 -> 21.07.0-3)
[2021-07-29T16:21:59+0800] [ALPM] upgraded flameshot (0.10.0-1 -> 0.10.1-1)
[2021-07-29T16:21:59+0800] [ALPM] upgraded feh (3.7-1 -> 3.7.1-1)
[2021-07-29T16:21:59+0800] [ALPM] upgraded f2fs-tools (1.14.0-1 -> 1.14.0-2)
[2021-07-29T16:21:59+0800] [ALPM] upgraded containerd (1.5.2-1 -> 1.5.4-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded cmake (3.21.0-1 -> 3.21.1-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded clazy (1.9-3 -> 1.10-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded cinnamon (5.0.5-3 -> 5.0.5-5)
[2021-07-29T16:21:58+0800] [ALPM] upgraded webkit2gtk (2.32.2-1 -> 2.32.3-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded perl (5.34.0-1 -> 5.34.0-2)
[2021-07-29T16:21:58+0800] [ALPM] upgraded libmm-glib (1.16.6-1 -> 1.16.8-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded dbus-python (1.2.16-4 -> 1.2.18-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded cinnamon-settings-daemon (5.0.3-2 -> 5.0.4-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded cinnamon-session (5.0.0-3 -> 5.0.1-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded xapp (2.2.2-1 -> 2.2.3-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded vulkan-icd-loader (1.2.184-1 -> 1.2.185-1)
[2021-07-29T16:21:58+0800] [ALPM] upgraded llvm-libs (12.0.1-1 -> 12.0.1-2)
[2021-07-29T16:21:57+0800] [ALPM] upgraded tdb (1.4.4-1 -> 1.4.5-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded gdk-pixbuf2 (2.42.6-1 -> 2.42.6-2)
[2021-07-29T16:21:57+0800] [ALPM] upgraded ceph-libs (15.2.13-1 -> 15.2.13-2)
[2021-07-29T16:21:57+0800] [ALPM] upgraded fmt (8.0.0-2 -> 8.0.1-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded brltty (6.3-3 -> 6.3-4)
[2021-07-29T16:21:57+0800] [ALPM] upgraded archlinux-appstream-data (20210612-1 -> 20210723-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded aom (3.1.1-1 -> 3.1.2-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded android-tools (31.0.0-4 -> 31.0.2-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded systemd (248.5-1 -> 248.6-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded curl (7.77.0-1 -> 7.78.0-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded libnghttp2 (1.43.0-1 -> 1.44.0-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded util-linux (2.37-3 -> 2.37.1-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded systemd-libs (248.5-1 -> 248.6-1)
[2021-07-29T16:21:57+0800] [ALPM] upgraded libldap (2.4.59-1 -> 2.4.59-2)
[2021-07-29T16:21:57+0800] [ALPM] upgraded util-linux-libs (2.37-3 -> 2.37.1-1)
/var/log/lightdm/lightdm.log.old:
[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.30.0, UID=0 PID=554
[+0.00s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration dirs from /var/lib/flatpak/exports/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
[+0.00s] DEBUG: [VNCServer] contains unknown option user-session
[+0.00s] DEBUG: [VNCServer] contains unknown option session-wrapper
[+0.00s] DEBUG: [VNCServer] contains unknown option autologin-user
[+0.00s] DEBUG: Registered seat module local
[+0.00s] DEBUG: Registered seat module xremote
[+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.00s] DEBUG: _g_io_module_get_default: Found default implementation local (GLocalVfs) for ‘gio-vfs’
[+0.02s] DEBUG: Monitoring logind for seats
[+0.02s] DEBUG: New seat added from logind: seat0
[+0.02s] DEBUG: Seat seat0: Loading properties from config section Seat:*
[+0.02s] DEBUG: Seat seat0 has property CanMultiSession=no
[+0.02s] DEBUG: Seat seat0: Starting
[+0.02s] DEBUG: Seat seat0: Creating user session
[+0.02s] DEBUG: Loading users from org.freedesktop.Accounts
[+0.02s] DEBUG: User /org/freedesktop/Accounts/User1000 added
[+0.02s] DEBUG: Seat seat0: Creating display server of type x
[+0.03s] DEBUG: Could not run plymouth --ping: Failed to execute child process “plymouth” (No such file or directory)
[+0.03s] DEBUG: Using VT 7
[+0.03s] DEBUG: Seat seat0: Starting local X display on VT 7
[+0.03s] DEBUG: XServer 0: Logging to /var/log/lightdm/x-0.log
[+0.03s] DEBUG: XServer 0: Writing X server authority to /run/lightdm/root/:0
[+0.03s] DEBUG: XServer 0: Launching X Server
[+0.03s] DEBUG: Launching process 588: /usr/bin/X :0 -seat seat0 -auth /run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.03s] DEBUG: XServer 0: Waiting for ready signal from X server :0
[+0.03s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.03s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+0.06s] DEBUG: Process 588 exited with return value 1
[+0.06s] DEBUG: XServer 0: X server stopped
[+0.06s] DEBUG: Releasing VT 7
[+0.06s] DEBUG: XServer 0: Removing X server authority /run/lightdm/root/:0
[+0.06s] DEBUG: Seat seat0: Display server stopped
[+0.06s] DEBUG: Seat seat0: Stopping session
[+0.06s] DEBUG: Seat seat0: Session stopped
[+0.06s] DEBUG: Seat seat0: Stopping display server, no sessions require it
[+0.06s] DEBUG: Seat seat0: Active display server stopped, starting greeter
[+0.06s] DEBUG: Seat seat0: Creating greeter session
[+0.06s] DEBUG: Seat seat0: Creating display server of type x
[+0.06s] DEBUG: Using VT 7
[+0.06s] DEBUG: Seat seat0: Starting local X display on VT 7
[+0.06s] DEBUG: XServer 0: Logging to /var/log/lightdm/x-0.log
[+0.06s] DEBUG: XServer 0: Writing X server authority to /run/lightdm/root/:0
[+0.06s] DEBUG: XServer 0: Launching X Server
[+0.06s] DEBUG: Launching process 615: /usr/bin/X :0 -seat seat0 -auth /run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.06s] DEBUG: XServer 0: Waiting for ready signal from X server :0
[+0.09s] DEBUG: Process 615 exited with return value 1
[+0.09s] DEBUG: XServer 0: X server stopped
[+0.09s] DEBUG: Releasing VT 7
[+0.09s] DEBUG: XServer 0: Removing X server authority /run/lightdm/root/:0
[+0.09s] DEBUG: Seat seat0: Display server stopped
[+0.09s] DEBUG: Seat seat0: Stopping session
[+0.09s] DEBUG: Seat seat0: Session stopped
[+0.09s] DEBUG: Seat seat0: Stopping display server, no sessions require it
[+0.09s] DEBUG: Seat seat0: Stopping; greeter display server failed to start
[+0.09s] DEBUG: Seat seat0: Stopping
[+0.09s] DEBUG: Seat seat0: Stopped
[+0.09s] DEBUG: Required seat has stopped
[+0.09s] DEBUG: Stopping display manager
[+0.09s] DEBUG: Display manager stopped
[+0.09s] DEBUG: Stopping daemon
[+0.09s] DEBUG: Exiting with return value 1
# screenfetch -n
r@r-lc
OS: Manjaro 21.1.0 Pahvo
Kernel: x86_64 Linux 5.4.135-1-MANJARO
Uptime: 15h 28m
Packages: 1648
Shell: bash 5.1.8
Resolution: 1920x1080
WM: i3
GTK Theme: Adwaita [GTK3]
Disk: 374G / 483G (81%)
CPU: AMD Ryzen 5 3400G with Radeon Vega Graphics @ 8x 3.7GHz
GPU: AMD Radeon(TM) Vega 11 Graphics (RAVEN, DRM 3.35.0, 5.4.135-1-MANJARO, LLVM 12.0.1)
RAM: 4115MiB / 30092MiB