gnome-shell crashed with SIGSEGV in meta_monitor_get_outputs (monitor=0x0) from meta_monitor_config_manager_assign()

[Guillaume Pothier]

https://errors.ubuntu.com/problem/930950abdb6648752bc30584d0833b348c68f0ba
https://errors.ubuntu.com/problem/50192237f22f17593e486f3349bf4770a1e28002
https://errors.ubuntu.com/problem/717fc039791d35516db85b1057b844960bb16d57
https://errors.ubuntu.com/problem/fffcd112bc9125d02cba17f6d7df29cd806c4912

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I don't really know what caused this, I didn't notice anything out of the ordinary, so I'm not sure exactly when it occurred. I usually plug and unplug an external monitor, this seems related.

ProblemType: Crash
DistroRelease: Ubuntu 20.04
Package: gnome-shell 3.36.0-2ubuntu2
ProcVersionSignature: Ubuntu 5.4.0-18.22-generic 5.4.24
Uname: Linux 5.4.0-18-generic x86_64
ApportVersion: 2.20.11-0ubuntu22
Architecture: amd64
CurrentDesktop: GNOME
Date: Thu Apr 2 19:31:02 2020
DisplayManager: gdm3
ExecutablePath: /usr/bin/gnome-shell
InstallationDate: Installed on 2018-12-14 (475 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
ProcCmdline: /usr/bin/gnome-shell
RelatedPackageVersions: mutter-common 3.36.0-2ubuntu1
SegvAnalysis:
 Segfault happened at: 0x7fdf6e50156b <meta_monitor_get_outputs+11>: mov 0x8(%rax,%rdi,1),%rax
 PC (0x7fdf6e50156b) ok
 source "0x8(%rax,%rdi,1)" (0xffffffffffffffb8) not located in a known VMA region (needed readable region)!
 destination "%rax" ok
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: gnome-shell
StacktraceTop:
 meta_monitor_get_outputs () at /usr/lib/x86_64-linux-gnu/libmutter-6.so.0
 meta_monitor_config_manager_assign () at /usr/lib/x86_64-linux-gnu/libmutter-6.so.0
 () at /usr/lib/x86_64-linux-gnu/libmutter-6.so.0
 () at /usr/lib/x86_64-linux-gnu/libmutter-6.so.0
 () at /usr/lib/x86_64-linux-gnu/libmutter-6.so.0
Title: gnome-shell crashed with SIGSEGV in meta_monitor_get_outputs()
UpgradeStatus: Upgraded to focal on 2020-03-25 (8 days ago)
UserGroups: adm cdrom dialout dip docker libvirt lpadmin plugdev sambashare sudo vboxusers
separator:

[Apport retracing service (apport)]

StacktraceTop:
 meta_monitor_get_outputs (monitor=0x0) at ../src/backends/meta-monitor.c:295
 meta_monitor_config_manager_assign (manager=manager@entry=0x56172ed9cb10, config=config@entry=0x56173035edc0, out_crtc_infos=out_crtc_infos@entry=0x7ffc62fbae18, out_output_infos=out_output_infos@entry=0x7ffc62fbae20, error=0x7ffc62fbaea0) at ../src/backends/meta-monitor-config-manager.c:400
 meta_monitor_manager_xrandr_apply_monitors_config (manager=0x56172ed9cb10, config=0x56173035edc0, method=META_MONITORS_CONFIG_METHOD_TEMPORARY, error=<optimized out>) at ../src/backends/x11/meta-monitor-manager-xrandr.c:851
 meta_monitor_manager_apply_monitors_config (manager=<optimized out>, config=<optimized out>, method=<optimized out>, error=<optimized out>) at ../src/backends/meta-monitor-manager.c:630
 orientation_changed (orientation_manager=<optimized out>, manager=<optimized out>) at ../src/backends/meta-monitor-manager.c:842

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daniel van Vugt (vanvugt)]

Tracking in https://errors.ubuntu.com/problem/930950abdb6648752bc30584d0833b348c68f0ba

but see also https://errors.ubuntu.com/problem/50192237f22f17593e486f3349bf4770a1e28002 and https://errors.ubuntu.com/problem/717fc039791d35516db85b1057b844960bb16d57

[Daniel van Vugt (vanvugt)]

The Wayland version of this crash is being tracked in:
https://errors.ubuntu.com/problem/fffcd112bc9125d02cba17f6d7df29cd806c4912