gnome-shell crashed with SIGSEGV with fractional scaling enabled

[Joe Barnett]

I enabled the 'scale-monitor-framebuffer' experimental mutter setting to try out fractional scaling, and ended up seeing quite frequent crashes of gnome-shell. Disabled it again, but filing this bug report to track.

ProblemType: Crash
DistroRelease: Ubuntu 17.10
Package: gnome-shell 3.25.91-0ubuntu4
ProcVersionSignature: Ubuntu 4.12.0-13.14-generic 4.12.10
Uname: Linux 4.12.0-13-generic x86_64
ApportVersion: 2.20.7-0ubuntu1
Architecture: amd64
CurrentDesktop: GNOME
Date: Thu Sep 14 07:15:03 2017
DisplayManager: gdm3
EcryptfsInUse: Yes
ExecutablePath: /usr/bin/gnome-shell
InstallationDate: Installed on 2015-08-21 (755 days ago)
InstallationMedia: Ubuntu-GNOME 15.10 "Wily Werewolf" - Alpha amd64 (20150819)
ProcCmdline: /usr/bin/gnome-shell
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7f161ba51a80: mov 0x80(%rdi),%eax
 PC (0x7f161ba51a80) ok
 source "0x80(%rdi)" (0x00000080) not located in a known VMA region (needed readable region)!
 destination "%eax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: gnome-shell
StacktraceTop:
 () at /usr/lib/gnome-shell/libst-1.0.so
 () at /usr/lib/gnome-shell/libst-1.0.so
 st_theme_node_paint () at /usr/lib/gnome-shell/libst-1.0.so
 st_widget_paint_background () at /usr/lib/gnome-shell/libst-1.0.so
 () at /usr/lib/gnome-shell/libst-1.0.so
Title: gnome-shell crashed with SIGSEGV
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip docker input lpadmin lxd plugdev sambashare sudo systemd-journal wireshark

[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 #1714542, 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.