gnome-shell crashed with SIGSEGV in meta_window_get_monitor()

[Roger Schaer]

Description
-----------
I am using 2 monitors connected via DisplayPort to a NVIDIA Quadro K2200 GPU. Every time I turn off the monitors, this bug happens when I turn them back on, and I need to restart "gnome-shell" via Alt+F2 -> R. This happens both with the "nouveau" and NVIDIA drivers. This has been happening since Ubuntu 17.04 if I remember correctly.

Additional Info
---------------

1) Ubuntu Release : 18.04 (Ubuntu Bionic Beaver (development branch)
2) gnome-shell version : 3.28.0.0ubuntu2
3) What is expected : After turning off my monitors, they should turn on again and gnome-shell should restore the GUI correctly.
4) What happens : gnome-shell crashes every time I turn my monitors off and on again.

ProblemType: Crash
DistroRelease: Ubuntu 18.04
Package: gnome-shell 3.28.0-0ubuntu2
ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10
Uname: Linux 4.15.0-13-generic x86_64
ApportVersion: 2.20.9-0ubuntu2
Architecture: amd64
CrashCounter: 1
CurrentDesktop: ubuntu:GNOME
Date: Wed Apr 4 17:37:10 2018
DisplayManager: gdm3
ExecutablePath: /usr/bin/gnome-shell
GsettingsChanges:
 b'org.gnome.shell' b'command-history' b"['r', 'update-manager -cd', 'r']"
 b'org.gnome.shell' b'favorite-apps' b"['org.gnome.Nautilus.desktop', 'unity-mail.desktop', 'telegramdesktop.desktop', 'slack_slack.desktop', 'eu.tiliado.NuvolaAppYoutube.desktop', 'eu.tiliado.NuvolaAppGooglePlayMusic.desktop', 'google-play-music-desktop-player.desktop', 'firefox.desktop', 'google-chrome.desktop', 'yakyak.desktop', 'org.gnome.Terminal.desktop', 'gnome-system-monitor.desktop', 'eclipse-oxygen.desktop', 'netbeans_ide_8_2.desktop', 'jetbrains-webstorm.desktop', 'jetbrains-idea.desktop']"
 b'org.gnome.desktop.interface' b'gtk-im-module' b"'gtk-im-context-simple'"
 b'org.gnome.desktop.interface' b'clock-show-seconds' b'true'
 b'org.gnome.desktop.interface' b'clock-show-date' b'true'
InstallationDate: Installed on 2016-09-05 (576 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
ProcCmdline: /usr/bin/gnome-shell
SegvAnalysis:
 Segfault happened at: 0x7efe762e6c24 <meta_window_get_monitor+4>: mov 0x18(%rax),%eax
 PC (0x7efe762e6c24) ok
 source "0x18(%rax)" (0x00000018) not located in a known VMA region (needed readable region)!
 destination "%eax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: gnome-shell
StacktraceTop:
 meta_window_get_monitor () at /usr/lib/x86_64-linux-gnu/libmutter-2.so.0
 ffi_call_unix64 () at /usr/lib/x86_64-linux-gnu/libffi.so.6
 ffi_call () at /usr/lib/x86_64-linux-gnu/libffi.so.6
 () at /usr/lib/libgjs.so.0
 () at /usr/lib/libgjs.so.0
Title: gnome-shell crashed with SIGSEGV in meta_window_get_monitor()
UpgradeStatus: Upgraded to bionic on 2018-03-23 (12 days ago)
UserGroups: adm cdrom dip docker lpadmin plugdev sambashare sudo

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1724439, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.