gnome-shell crashed with SIGSEGV in st_theme_node_get_border_image() from st_theme_node_paint_equal() from st_widget_recompute_style()

[Cliff Stanford]

https://errors.ubuntu.com/problem/40c10d17842e966b2b77712dd58f500272d16dd8

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This crash occurs around 50% of the time on automatic screen lock or possible on screen blank.

ProblemType: Crash
DistroRelease: Ubuntu 20.04
Package: gnome-shell 3.36.2-1ubuntu1~20.04.1
ProcVersionSignature: Ubuntu 5.4.0-33.37-generic 5.4.34
Uname: Linux 5.4.0-33-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.2
Architecture: amd64
CasperMD5CheckResult: skip
CrashCounter: 1
CurrentDesktop: GNOME
Date: Sat May 30 18:29:24 2020
DisplayManager: gdm3
ExecutablePath: /usr/bin/gnome-shell
InstallationDate: Installed on 2020-05-21 (9 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
ProcCmdline: /usr/bin/gnome-shell
RelatedPackageVersions: mutter-common 3.36.2-1ubuntu1~20.04.1
SegvAnalysis:
 Segfault happened at: 0x7f7ce568a7ff <st_theme_node_get_border_image+191>: mov (%rax),%rsi
 PC (0x7f7ce568a7ff) ok
 source "(%rax)" (0x00000260) not located in a known VMA region (needed readable region)!
 destination "%rsi" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: gnome-shell
StacktraceTop:
 st_theme_node_get_border_image () from /usr/lib/gnome-shell/libst-1.0.so
 st_theme_node_paint_equal () from /usr/lib/gnome-shell/libst-1.0.so
 ?? () from /usr/lib/gnome-shell/libst-1.0.so
 st_widget_style_changed () from /usr/lib/gnome-shell/libst-1.0.so
 ?? () from /usr/lib/gnome-shell/libst-1.0.so
Title: gnome-shell crashed with SIGSEGV in st_theme_node_get_border_image()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin lxd plugdev sambashare sudo
mtime.conffile..etc.apport.crashdb.conf: 2020-05-29T18:09:27.628392
separator:

[Apport retracing service (apport)]

StacktraceTop:
 st_theme_node_get_border_image () from /tmp/apport_sandbox_pcsg1tln/usr/lib/gnome-shell/libst-1.0.so
 st_theme_node_paint_equal () from /tmp/apport_sandbox_pcsg1tln/usr/lib/gnome-shell/libst-1.0.so
 st_widget_recompute_style () from /tmp/apport_sandbox_pcsg1tln/usr/lib/gnome-shell/libst-1.0.so
 st_widget_style_changed () from /tmp/apport_sandbox_pcsg1tln/usr/lib/gnome-shell/libst-1.0.so
 notify_children_of_style_change () from /tmp/apport_sandbox_pcsg1tln/usr/lib/gnome-shell/libst-1.0.so

[Daniel van Vugt (vanvugt)]

Confirmed by: https://errors.ubuntu.com/problem/40c10d17842e966b2b77712dd58f500272d16dd8

But still, please run 'gnome-shell-extension-prefs' and try disabling some/all of your extensions so we can find out which (if any) are the cause.

[Daniel Rodriguez (newhacker1746)]

I think I have this issue, but I'm not 100% sure. I tried to find the crash log in /var/crash, but it looks slightly different. There's no segvanalysis or stacktrace, though I can find a signal 11 crash in /var/log/apport.log. How can I go about confirming this is the bug I'm experiencing?

[Daniel van Vugt (vanvugt)]

Daniel, please use these instructions:

https://wiki.ubuntu.com/Bugs/Responses#Missing_a_crash_report_or_having_a_.crash_attachment