Bug#839236: sddm fails to display anything. segfault in sddm-greeter

[Jon Parker <parker.jon+debian@gmail.com>]

Package: sddm
Version: 0.13.0-1
Followup-For: Bug #839236

Dear Maintainer,

A recent update is causing sddm to segfault on startup.  Starting kde from console using startx works fine.
I can also avoid the issue by setting kde to autologin my account.  Here is a relevant error message from journalctl:

Oct 04 12:19:12 clambox kernel: QSGRenderThread[4747]: segfault at 0 ip 00007fc839aeb66d sp 00007fc8124bbc28 error 4 in libc-2.24.so[7fc839a53000+195000]


-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.7.0-1-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages sddm depends on:
ii  adduser                         3.115
ii  debconf [debconf-2.0]           1.5.59
ii  libc6                           2.24-3
ii  libgcc1                         1:6.1.1-11
ii  libpam0g                        1.1.8-3.3
ii  libqt5core5a                    5.6.1+dfsg-3+b1
ii  libqt5dbus5                     5.6.1+dfsg-3+b1
ii  libqt5gui5                      5.6.1+dfsg-3+b1
ii  libqt5network5                  5.6.1+dfsg-3+b1
ii  libqt5qml5                      5.6.1-8
ii  libqt5quick5                    5.6.1-8
ii  libstdc++6                      6.1.1-11
ii  libsystemd0                     231-4
ii  libxcb-xkb1                     1.12-1
ii  libxcb1                         1.12-1
ii  qml-module-qtquick2             5.6.1-8
ii  sddm-theme-breeze [sddm-theme]  4:5.7.4-1

Versions of packages sddm recommends:
ii  libpam-systemd  231-4

Versions of packages sddm suggests:
ii  libpam-kwallet5  5.7.4-1

-- debconf information:
  sddm/daemon_name: /usr/bin/sddm
* shared/default-x-display-manager: sddm