Bug 400058

Summary: kscreenlocker_greet crashes every time
Product: [Unmaintained] kscreenlocker Reporter: Chris Cheney <chris.cheney>
Component: greeterAssignee: Plasma Bugs List <plasma-bugs-null>
Status: RESOLVED FIXED    
Severity: crash CC: bshah, chuck.ard1, jordanleppert, kde
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Neon   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Chris Cheney 2018-10-20 06:00:52 UTC 
SUMMARY

Upgraded neon today, there were plenty of kde related updates, and now kscreenlocker_greet crashes every time the screen is locked and causes a screen that says "loginctl unlock-session #" to unlock to appear.

Rebooting, removing kde related cache files under $HOME/.cache/, etc doesn't help.


STEPS TO REPRODUCE
1. Upgraded to current neon today
2. Broke


OBSERVED RESULT

  Error screen


EXPECTED RESULT

  Should work


SOFTWARE VERSIONS
(available in About System)  -- THIS TEMPLATE NEEDS TO BE FIXED WHERE IS ABOUT SYETEM?
KDE Plasma Version:      5.14.1-0xneon+18.04+bionic+build (various numbers)
KDE Frameworks Version:  5.51.0-0xneon+18.04+bionic+build (various numbers)
Qt Version:              5.11.2+dfsg-0xneon+18.04+bionic+build (various numbers)


ADDITIONAL INFORMATION

.xsession-errors shows the following:

KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kscreenlocker_greet path = /usr/lib/x86_64-linux-gnu/libexec pid = 10400
KCrash: Arguments: /usr/lib/x86_64-linux-gnu/libexec/kscreenlocker_greet --immediateLock --graceTime 5000 --ksldfd 38 
UnmapNotify: 90177550
UnmapNotify: 90177553
UnmapNotify: 90177555
UnmapNotify: 90177575
CreateNotify: 90177540
Qt: Session management error: networkIdsList argument is NULL
CreateNotify: 90177544
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 9004, resource id: 90177575, major code: 3 (GetWindowAttributes), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 9 (BadDrawable), sequence: 9005, resource id: 90177575, major code: 14 (GetGeometry), minor code: 0
CreateNotify: 90177549
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
CreateNotify: 90177550
CreateNotify: 90177552
MapNotify: 90177550
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
CreateNotify: 90177553
MapNotify: 90177553
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
CreateNotify: 90177555
MapNotify: 90177555
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
UdevQt: unable to create udev monitor connection
CreateNotify: 90177567
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
file:///usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/VirtualKeyboard.qml:22:1: Type InputPanel unavailable
qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
file:///usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/VirtualKeyboard.qml:22:1: Type InputPanel unavailable
qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
file:///usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/VirtualKeyboard.qml:22:1: Type InputPanel unavailable
qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
QObject::connect: invalid null parameter
CreateNotify: 90177575
MapNotify: 90177575
QObject::connect: invalid null parameter
QObject::connect: invalid null parameter
QObject::connect: invalid null parameter
QObject::connect: invalid null parameter
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kscreenlocker_greet path = /usr/lib/x86_64-linux-gnu/libexec pid = 10410
KCrash: Arguments: /usr/lib/x86_64-linux-gnu/libexec/kscreenlocker_greet --immediateLock --graceTime 5000 --ksldfd 38 
UnmapNotify: 90177550
UnmapNotify: 90177553
UnmapNotify: 90177555
UnmapNotify: 90177575
MapNotify: 27263016
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 9103, resource id: 90177552, major code: 18 (ChangeProperty), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 9105, resource id: 90177550, major code: 3 (GetWindowAttributes), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 9 (BadDrawable), sequence: 9106, resource id: 90177550, major code: 14 (GetGeometry), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 9109, resource id: 90177553, major code: 3 (GetWindowAttributes), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 9 (BadDrawable), sequence: 9110, resource id: 90177553, major code: 14 (GetGeometry), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 9113, resource id: 90177555, major code: 3 (GetWindowAttributes), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 9 (BadDrawable), sequence: 9114, resource id: 90177555, major code: 14 (GetGeometry), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 9117, resource id: 90177575, major code: 3 (GetWindowAttributes), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 9 (BadDrawable), sequence: 9118, resource id: 90177575, major code: 14 (GetGeometry), minor code: 0
Grab Released
powerdevil: ACTIVE SESSION PATH CHANGED: "/org/freedesktop/login1/session/_33"
powerdevil: Current session is now active
powerdevil: ACTIVE SESSION PATH CHANGED: "/org/freedesktop/login1/session/_33"
powerdevil: Current session is now active
Initializing  "kcm_mouse" :  "kcminit_mouse"
kdeinit5: Got SETENV 'XCURSOR_THEME=breeze_cursors' from launcher.
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 10242, resource id: 90177541, major code: 18 (ChangeProperty), minor code: 0
Initializing  "kcm_mouse" :  "kcminit_mouse"
kdeinit5: Got SETENV 'XCURSOR_THEME=breeze_cursors' from launcher.
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 10262, resource id: 92274693, major code: 18 (ChangeProperty), minor code: 0


Running the command directly from konsole shows the following:

$ /usr/lib/x86_64-linux-gnu/libexec/kscreenlocker_greet --immediateLock --graceTime 5000 --ksldfd 38
QSocketNotifier: Invalid socket 38 and type 'Read', disabling...
OpenGL vendor string:                   Intel Open Source Technology Center
OpenGL renderer string:                 Mesa DRI Intel(R) HD Graphics 530 (Skylake GT2) 
OpenGL version string:                  3.0 Mesa 18.0.5
OpenGL shading language version string: 1.30
Driver:                                 Intel
GPU class:                              Unknown
OpenGL version:                         3.0
GLSL version:                           1.30
Mesa version:                           18.0.5
Linux kernel version:                   4.15
Requires strict binding:                yes
GLSL shaders:                           yes
Texture NPOT support:                   yes
Virtual Machine:                        no
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
Locked at 1540015175
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
kf5.kpackage: No metadata file in the package, expected it at: "/media/hdd/users/ccheney/Downloads/"
UdevQt: unable to create udev monitor connection
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
file:///usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/VirtualKeyboard.qml:22:1: Type InputPanel unavailable
qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
file:///usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/VirtualKeyboard.qml:22:1: Type InputPanel unavailable
qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
file:///usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/VirtualKeyboard.qml:22:1: Type InputPanel unavailable
qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
QObject::connect: invalid null parameter
QObject::connect: invalid null parameter
QObject::connect: invalid null parameter
QObject::connect: invalid null parameter
QObject::connect: invalid null parameter
Segmentation fault
Comment 1 JordanL 2018-10-20 17:22:36 UTC 
I have a similar issue. In my case it happens when I click the password field of the greeter screen. I have SDDM configured to auto-login to my user account, so I log out to get back to the login screen first, in case that makes a difference.


System:    Host: rupert Kernel: 4.15.0-36-generic x86_64 bits: 64 gcc: 7.3.0
           Desktop: KDE Plasma 5.14.1 (Qt 5.11.2) Distro: KDE neon User Edition 5.14
Machine:   Device: desktop Mobo: MSI model: X99S SLI PLUS (MS-7885) v: 1.0 serial: N/A
           UEFI: American Megatrends v: 1.E0 date: 06/15/2018
CPU:       6 core Intel Core i7-5820K (-MT-MCP-) arch: Haswell rev.2 cache: 15360 KB
           flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 39603
           clock speeds: max: 3600 MHz 1: 1200 MHz 2: 1200 MHz 3: 1200 MHz 4: 1211 MHz 5: 1204 MHz 6: 1200 MHz
           7: 1200 MHz 8: 1200 MHz 9: 1200 MHz 10: 1567 MHz 11: 1207 MHz 12: 1200 MHz
Graphics:  Card: Advanced Micro Devices [AMD/ATI] Vega [Radeon RX Vega] bus-ID: 05:00.0
           Display Server: x11 (X.Org 1.19.6 ) drivers: ati,amdgpu (unloaded: modesetting,fbdev,vesa,radeon)
           Resolution: 3840x2160@60.00hz, 3840x2160@60.00hz
           OpenGL: renderer: Radeon RX Vega (VEGA10 / DRM 3.23.0 / 4.15.0-36-generic, LLVM 6.0.0)
           version: 4.5 Mesa 18.0.5 Direct Render: Yes
Audio:     Card-1 Advanced Micro Devices [AMD/ATI] Device aaf8 driver: snd_hda_intel bus-ID: 05:00.1
           Card-2 Intel C610/X99 series HD Audio Controller driver: snd_hda_intel bus-ID: 00:1b.0
           Sound: Advanced Linux Sound Architecture v: k4.15.0-36-generic
Network:   Card: Intel Ethernet Connection (2) I218-V driver: e1000e v: 3.2.6-k port: f020 bus-ID: 00:19.0
           IF: eno1 state: up speed: 1000 Mbps duplex: full mac: <filter>
Drives:    HDD Total Size: 500.1GB (29.4% used)
           ID-1: /dev/sda model: Samsung_SSD_840 size: 500.1GB
Partition: ID-1: / size: 457G used: 137G (32%) fs: ext4 dev: /dev/sda2
RAID:      No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors:   System Temperatures: cpu: 35.0C mobo: N/A gpu: 40.0
           Fan Speeds (in rpm): cpu: N/A
Info:      Processes: 279 Uptime: 9 min Memory: 2103.9/11905.9MB Init: systemd runlevel: 5 Gcc sys: 7.3.0
           Client: Shell (bash 4.4.191) inxi: 2.3.56 


Logs from journalctl:

Oct 20 18:07:26 rupert systemd[1]: Started User Manager for UID 117.
Oct 20 18:07:26 rupert sddm[903]: Greeter session started successfully
Oct 20 18:07:26 rupert sddm-greeter[2148]: High-DPI autoscaling not Enabled
Oct 20 18:07:26 rupert sddm-greeter[2148]: Loading theme configuration from "/usr/share/sddm/themes/breeze/theme.conf"
Oct 20 18:07:26 rupert sddm-greeter[2148]: Reading from "/usr/share/xsessions/plasma.desktop"
Oct 20 18:07:26 rupert sddm-greeter[2148]: Reading from "/usr/share/wayland-sessions/plasmawayland.desktop"
Oct 20 18:07:26 rupert sddm-greeter[2148]: Connected to the daemon.
Oct 20 18:07:26 rupert sddm[903]: Message received from greeter: Connect
Oct 20 18:07:26 rupert sddm-greeter[2148]: Loading file:///usr/share/sddm/themes/breeze/Main.qml...
Oct 20 18:07:26 rupert sddm-greeter[2148]: QObject: Cannot create children for a parent that is in a different thread.
                                           (Parent is SDDM::GreeterApp(0x7fffa09028f0), parent's thread is QThread(0x560a44709020), current thread is QThread(0x560a449563c0)
Oct 20 18:07:26 rupert sddm-greeter[2148]: QObject: Cannot create children for a parent that is in a different thread.
                                           (Parent is SDDM::GreeterApp(0x7fffa09028f0), parent's thread is QThread(0x560a44709020), current thread is QThread(0x560a449563c0)
Oct 20 18:07:26 rupert sddm-greeter[2148]: QObject: Cannot create children for a parent that is in a different thread.
                                           (Parent is SDDM::GreeterApp(0x7fffa09028f0), parent's thread is QThread(0x560a44709020), current thread is QThread(0x560a449563c0)
Oct 20 18:07:26 rupert sddm-greeter[2148]: QObject: Cannot create children for a parent that is in a different thread.
                                           (Parent is SDDM::GreeterApp(0x7fffa09028f0), parent's thread is QThread(0x560a44709020), current thread is QThread(0x560a449563c0)
Oct 20 18:07:26 rupert sddm-greeter[2148]: QObject::installEventFilter(): Cannot filter events for objects in a different thread.
Oct 20 18:07:26 rupert sddm-greeter[2148]: QObject: Cannot create children for a parent that is in a different thread.
                                           (Parent is SDDM::GreeterApp(0x7fffa09028f0), parent's thread is QThread(0x560a44709020), current thread is QThread(0x560a449563c0)
Oct 20 18:07:26 rupert dbus-daemon[2164]: [session uid=117 pid=2162] AppArmor D-Bus mediation is enabled
Oct 20 18:07:26 rupert sddm-greeter[2148]: QObject: Cannot create children for a parent that is in a different thread.
                                           (Parent is SDDM::GreeterApp(0x7fffa09028f0), parent's thread is QThread(0x560a44709020), current thread is QThread(0x560a449563c0)
Oct 20 18:07:26 rupert sddm-greeter[2148]: QObject::installEventFilter(): Cannot filter events for objects in a different thread.
Oct 20 18:07:26 rupert sddm-greeter[2148]: Cannot watch QRC-like path ":/icons/hicolor/index.theme"
Oct 20 18:07:26 rupert sddm-greeter[2148]: file:///usr/share/sddm/themes/breeze/components/VirtualKeyboard.qml:22:1: Type InputPanel unavailable
Oct 20 18:07:26 rupert sddm-greeter[2148]: qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
Oct 20 18:07:26 rupert sddm-greeter[2148]: Adding view for "DisplayPort-0" QRect(0,0 3840x2160)
Oct 20 18:07:26 rupert sddm-greeter[2148]: Loading file:///usr/share/sddm/themes/breeze/Main.qml...
Oct 20 18:07:26 rupert sddm-greeter[2148]: file:///usr/share/sddm/themes/breeze/components/VirtualKeyboard.qml:22:1: Type InputPanel unavailable
Oct 20 18:07:26 rupert sddm-greeter[2148]: qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
Oct 20 18:07:26 rupert sddm-greeter[2148]: Adding view for "DisplayPort-1" QRect(3840,0 3840x2160)
Oct 20 18:07:26 rupert sddm-greeter[2148]: Message received from daemon: Capabilities
Oct 20 18:07:26 rupert sddm-greeter[2148]: Message received from daemon: HostName
Oct 20 18:07:27 rupert sddm-greeter[2148]: qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml: File was compiled ahead of time with an incompatible version of Qt and the original file cannot be found. Please recompile
Oct 20 18:07:27 rupert sddm-greeter[2148]: QObject::connect: invalid null parameter
Oct 20 18:07:31 rupert sddm-greeter[2148]: QObject::connect: invalid null parameter
Oct 20 18:07:31 rupert sddm-greeter[2148]: QObject::connect: invalid null parameter
Oct 20 18:07:31 rupert sddm-greeter[2148]: QObject::connect: invalid null parameter
Oct 20 18:07:31 rupert sddm-greeter[2148]: QObject::connect: invalid null parameter
Oct 20 18:07:31 rupert kernel: [drm] HBR2x4 pass VS=2, PE=0
Oct 20 18:07:31 rupert kernel: show_signal_msg: 15 callbacks suppressed
Oct 20 18:07:31 rupert kernel: sddm-greeter[2148]: segfault at 8 ip 00007fb4871e9930 sp 00007fffa0901d58 error 4 in libqtvirtualkeyboardplugin.so[7fb4871be000+299000]
Oct 20 18:07:31 rupert sddm-helper[2134]: [PAM] Closing session
Oct 20 18:07:31 rupert sddm-helper[2134]: pam_unix(sddm-greeter:session): session closed for user sddm
Oct 20 18:07:31 rupert sddm-helper[2134]: [PAM] Ended.
Oct 20 18:07:31 rupert sddm[903]: Auth: sddm-helper exited with 11
Oct 20 18:07:31 rupert sddm[903]: Greeter stopped.
Oct 20 18:07:31 rupert systemd[1]: session-4.scope: Killing process 2163 (dbus-launch) with signal SIGTERM.
Oct 20 18:07:31 rupert systemd[1]: session-4.scope: Killing process 2164 (dbus-daemon) with signal SIGTERM.
Oct 20 18:07:31 rupert systemd[1]: Stopping Session 4 of user sddm.
Oct 20 18:07:31 rupert systemd[1]: Stopped Session 4 of user sddm.
Oct 20 18:07:31 rupert systemd-logind[783]: Removed session 4.
Oct 20 18:07:31 rupert systemd[1]: Stopping User Manager for UID 117...
Oct 20 18:07:31 rupert systemd[2137]: Stopped target Default.
Oct 20 18:07:31 rupert systemd[2137]: Stopped target Basic System.
Oct 20 18:07:31 rupert systemd[2137]: Stopped target Paths.
Oct 20 18:07:31 rupert systemd[2137]: Stopped target Timers.
Oct 20 18:07:31 rupert systemd[2137]: Stopped target Sockets.
Oct 20 18:07:31 rupert systemd[2137]: Closed GnuPG network certificate management daemon.
Oct 20 18:07:31 rupert systemd[2137]: Closed GnuPG cryptographic agent and passphrase cache (access for web browsers).
Oct 20 18:07:31 rupert systemd[2137]: Closed GnuPG cryptographic agent and passphrase cache (restricted).
Oct 20 18:07:31 rupert systemd[2137]: Closed GnuPG cryptographic agent and passphrase cache.
Oct 20 18:07:31 rupert systemd[2137]: Closed GnuPG cryptographic agent (ssh-agent emulation).
Oct 20 18:07:31 rupert systemd[2137]: Reached target Shutdown.
Oct 20 18:07:31 rupert systemd[2137]: Starting Exit the Session...
Oct 20 18:07:31 rupert systemd[2137]: Received SIGRTMIN+24 from PID 2172 (kill).
Oct 20 18:07:31 rupert systemd[1]: Stopped User Manager for UID 117.
Oct 20 18:07:31 rupert systemd[1]: Removed slice User Slice of sddm.
Comment 2 JordanL 2018-10-20 20:29:34 UTC 
My issue also started today, after the update of Qt to 5.11.2. It happens whether the Plasma or the Plasma Wayland session is selected. I was going to file a bug for SDDM, but couldn't find it (is it not a KDE project?).
Comment 3 David Edmundson 2018-10-20 21:26:39 UTC 
Please get a backtrace of the crash

though it'll almost certainly be your graphics drivers, so please check them
Comment 4 Chris Cheney 2018-10-21 05:13:56 UTC 
How do you get a core/backtrace from kscreenlocker_greet?

I tried running ulimit -c unlimited in neon and then the program but it still didn't create a core file when I ran kscrenlocker_greet from the command line.
Comment 5 Chris Cheney 2018-10-21 05:16:37 UTC 
Also while it is possible it is the video driver that is the problem no xorg packages have been updated since Sept 25, but the problem didn't show up until the large set of KDE updates on Oct 19.
Comment 6 Chris Cheney 2018-10-21 05:19:38 UTC 
I just noticed a big Qt update got pushed to neon today which fixed the problem.

Apparently KDE/Qt updates are very fragile, and is not reflected by soname updates. :-\
Comment 7 JordanL 2018-10-21 10:48:39 UTC 
I too can confirm the issue is fixed since the second batch of Qt updates.
Comment 8 David Edmundson 2018-10-21 17:38:09 UTC 
Thanks for reporting back