Arch Linux

Description:

After last system update sddm.service fails to start.
"Failed to read display number from pipe"

Before update had dependency problems with python-pyqt5, pyqt5-common and xorgproto.

Additional info:
Jan 03 15:08:25 peekon systemd[1]: Started Simple Desktop Display Manager.
Jan 03 15:08:25 peekon sddm[2108]: Initializing...
Jan 03 15:08:25 peekon sddm[2108]: Starting...
Jan 03 15:08:25 peekon sddm[2108]: Logind interface found
Jan 03 15:08:25 peekon sddm[2108]: Adding new display on vt 1 ...
Jan 03 15:08:25 peekon sddm[2108]: Loading theme configuration from ""
Jan 03 15:08:25 peekon sddm[2108]: Display server starting...
Jan 03 15:08:25 peekon sddm[2108]: Running: /usr/bin/X -nolisten tcp -auth /var/run/sddm/{1929e263-0719-4c1b-afbc-614031ab984b} -background none -noreset ->
Jan 03 15:08:26 peekon sddm[2108]: Failed to read display number from pipe
Jan 03 15:08:26 peekon sddm[2108]: Display server failed to start. Exiting
Jan 03 15:08:26 peekon systemd[1]: sddm.service: Main process exited, code=dumped, status=6/ABRT
Jan 03 15:08:26 peekon systemd[1]: sddm.service: Failed with result 'core-dump'.
Jan 03 15:08:26 peekon systemd[1]: sddm.service: Scheduled restart job, restart counter is at 5.
Jan 03 15:08:26 peekon systemd[1]: Stopped Simple Desktop Display Manager.
Jan 03 15:08:26 peekon systemd[1]: sddm.service: Start request repeated too quickly.
Jan 03 15:08:26 peekon systemd[1]: sddm.service: Failed with result 'core-dump'.
Jan 03 15:08:26 peekon systemd[1]: Failed to start Simple Desktop Display Manager.

sddm code dump:
Stack trace of thread 2108:
#0 0x00007f2e810a8f25 raise (libc.so.6 + 0x3bf25)
#1 0x00007f2e81092897 abort (libc.so.6 + 0x25897)
#2 0x00007f2e814c896c _ZNK14QMessageLogger5fatalEPKcz (libQt5Core.so.5 + 0x8e96c)
#3 0x00005636916d40f5 n/a (sddm + 0x290f5)
#4 0x0000563691718ebe _ZN4SDDM4Seat13createDisplayEi (sddm + 0x6debe)
#5 0x0000563691719102 _ZN4SDDM4SeatC2ERK7QStringP7QObject (sddm + 0x6e102)
#6 0x000056369171b0c1 _ZN4SDDM11SeatManager10createSeatERK7QString (sddm + 0x700c1)
#7 0x000056369171bee2 n/a (sddm + 0x70ee2)
#8 0x00007f2e8171433e n/a (libQt5Core.so.5 + 0x2da33e)
#9 0x000056369171a130 _ZN4SDDM10LogindSeat19canGraphicalChangedEb (sddm + 0x6f130)
#10 0x000056369171a443 n/a (sddm + 0x6f443)
#11 0x00007f2e8171433e n/a (libQt5Core.so.5 + 0x2da33e)
#12 0x00007f2e820d1a10 _ZN23QDBusPendingCallWatcher8finishedEPS_ (libQt5DBus.so.5 + 0x79a10)
#13 0x00007f2e820d1b11 n/a (libQt5DBus.so.5 + 0x79b11)
#14 0x00007f2e8170c13a _ZN7QObject5eventEP6QEvent (libQt5Core.so.5 + 0x2d213a)
#15 0x00007f2e816de810 _ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent (libQt5Core.so.5 + 0x2a4810)
#16 0x00007f2e816e1096 _ZN23QCoreApplicationPrivate16sendPostedEventsEP7QObjectiP11QThreadData (libQt5Core.so.5 + 0x2a7096)
#17 0x00007f2e81737674 n/a (libQt5Core.so.5 + 0x2fd674)
#18 0x00007f2e8029c39e g_main_context_dispatch (libglib-2.0.so.0 + 0x6a39e)
#19 0x00007f2e8029e1b1 n/a (libglib-2.0.so.0 + 0x6c1b1)
#20 0x00007f2e8029e1f1 g_main_context_iteration (libglib-2.0.so.0 + 0x6c1f1)
#21 0x00007f2e81736cc0 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2fccc0)
#22 0x00007f2e816dd39c _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2a339c)
#23 0x00007f2e816e53a6 _ZN16QCoreApplication4execEv (libQt5Core.so.5 + 0x2ab3a6)
#24 0x00005636916d78da main (sddm + 0x2c8da)
#25 0x00007f2e81094153 __libc_start_main (libc.so.6 + 0x27153)
#26 0x00005636916d7bde _start (sddm + 0x2cbde)

Stack trace of thread 2109:
#0 0x00007f2e811619ef __poll (libc.so.6 + 0xf49ef)
#1 0x00007f2e8029e120 n/a (libglib-2.0.so.0 + 0x6c120)
#2 0x00007f2e8029e1f1 g_main_context_iteration (libglib-2.0.so.0 + 0x6c1f1)
#3 0x00007f2e81736cc0 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2fccc0)
#4 0x00007f2e816dd39c _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2a339c)
#5 0x00007f2e81502e62 _ZN7QThread4execEv (libQt5Core.so.5 + 0xc8e62)
#6 0x00007f2e8206db28 n/a (libQt5DBus.so.5 + 0x15b28)
#7 0x00007f2e81503fd6 n/a (libQt5Core.so.5 + 0xc9fd6)
#8 0x00007f2e810544cf start_thread (libpthread.so.0 + 0x94cf)
#9 0x00007f2e8116c2d3 __clone (libc.so.6 + 0xff2d3)

Steps to reproduce:
1. Full update system.
2. After reboot or when restarting sddm service