Comment 0 for bug 1765353

Reproducible and discussed on the forums - https://ubuntuforums.org/showthread.php?t=2389622

Open "Settings" and navigate to "Users".

Click on "Unlock" and cancel dialog without inputting a password.

"Unlock" becomes unusable and Settings will eventually crash.

If started from a terminal I see the following output:

(gnome-control-center:24951): GLib-GIO-CRITICAL **: 10:26:38.402: g_permission_acquire_finish: assertion 'G_IS_PERMISSION (permission)' failed
fish: “gnome-control-center” terminated by signal SIGSEGV (Address boundary error)

ProblemType: Crash
DistroRelease: Ubuntu 18.04
Package: gnome-control-center 1:3.28.1-0ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-15.16-generic 4.15.15
Uname: Linux 4.15.0-15-generic x86_64
ApportVersion: 2.20.9-0ubuntu5
Architecture: amd64
CurrentDesktop: GNOME
Date: Thu Apr 19 10:25:11 2018
ExecutablePath: /usr/bin/gnome-control-center
InstallationDate: Installed on 2017-11-07 (163 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20171018)
ProcCmdline: gnome-control-center --overview
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7f7e2de3b845: pushq 0x8(%rax)
 PC (0x7f7e2de3b845) ok
 source "0x8(%rax)" (0x00000008) not located in a known VMA region (needed readable region)!
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: gnome-control-center
StacktraceTop:
 () at /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
 g_simple_async_result_complete () at /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
 () at /usr/lib/x86_64-linux-gnu/libpolkit-gobject-1.so.0
 g_simple_async_result_complete () at /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
 () at /usr/lib/x86_64-linux-gnu/libpolkit-gobject-1.so.0
Title: gnome-control-center crashed with SIGSEGV
UpgradeStatus: Upgraded to bionic on 2018-02-21 (56 days ago)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo