signon-ui crashed with SIGSEGV in QObject::event()

signon-ui crashed with SIGSEGV in QObject::event()

ProblemType: Crash
DistroRelease: Ubuntu 13.10
Package: signon-ui 0.15daily13.06.12-0ubuntu1
ProcVersionSignature: Ubuntu 3.10.0-5.15-generic 3.10.2
Uname: Linux 3.10.0-5-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.11-0ubuntu1
Architecture: amd64
Date: Mon Jul 29 21:41:58 2013
ExecutablePath: /usr/bin/signon-ui
InstallationDate: Installed on 2013-07-29 (0 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Alpha amd64 (20130728)
MarkForUpload: True
ProcCmdline: /usr/bin/signon-ui
ProcCwd: /home/hugh
ProcEnviron:
 SHELL=/bin/bash
 XDG_RUNTIME_DIR=<set>
 PATH=(custom, no user)
 LANGUAGE=en_GB:en
 LANG=en_GB.UTF-8
SegvAnalysis:
 Segfault happened at: 0x7fadb11638cb: mov 0x28(%rdi),%r12d
 PC (0x7fadb11638cb) ok
 source "0x28(%rdi)" (0x00000028) not located in a known VMA region (needed readable region)!
 destination "%r12d" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: signon-ui
StacktraceTop:
 ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
 ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
 ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
 ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
 QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
Title: signon-ui crashed with SIGSEGV in QObject::event()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo