gnome-shell assert failure: gnome-shell: ../../src/xcb_io.c:260: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.

[Kostas Vlachos]

Description: Ubuntu 20.04.2 LTS
Release: 20.04

gnome-shell:
  Installed: 3.36.7-0ubuntu0.20.04.1
  Candidate: 3.36.7-0ubuntu0.20.04.1
  Version table:
 *** 3.36.7-0ubuntu0.20.04.1 500
        500 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     3.36.4-1ubuntu1~20.04.2 500
        500 http://archive.ubuntu.com/ubuntu focal-security/main amd64 Packages
     3.36.1-5ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages

mutter 3.36.7

Description of issue: The GUI seems to freeze/reload/refresh instantly. It happens when I e.g. click on the docker panel and/or just move the mouse cursor around, click on apps and do something GUI related, open folders. The GUI reload/refresh crash lasts for about 2 seconds, it suddenly/instantly repositions my mouse cursor to the lower right corner of the screen and my laptop's fan works harder at those 2 seconds. The issue started after I updated and, at a later time, rebooted the machine.
Below are the gnome-related upgrades that I did (`cat /var/log/dpkg.log | grep gnome`):

2021-04-15 17:50:29 status triggers-pending gnome-menus:amd64 3.36.0-1ubuntu1
2021-04-15 17:50:30 upgrade libreoffice-gnome:amd64 1:6.4.6-0ubuntu0.20.04.1 1:6.4.7-0ubuntu0.20.04.1
2021-04-15 17:50:30 status half-configured libreoffice-gnome:amd64 1:6.4.6-0ubuntu0.20.04.1
2021-04-15 17:50:30 status unpacked libreoffice-gnome:amd64 1:6.4.6-0ubuntu0.20.04.1
2021-04-15 17:50:30 status half-installed libreoffice-gnome:amd64 1:6.4.6-0ubuntu0.20.04.1
2021-04-15 17:50:30 status unpacked libreoffice-gnome:amd64 1:6.4.7-0ubuntu0.20.04.1
2021-04-15 17:50:56 configure libreoffice-gnome:amd64 1:6.4.7-0ubuntu0.20.04.1 <none>
2021-04-15 17:50:56 status unpacked libreoffice-gnome:amd64 1:6.4.7-0ubuntu0.20.04.1
2021-04-15 17:50:56 status half-configured libreoffice-gnome:amd64 1:6.4.7-0ubuntu0.20.04.1
2021-04-15 17:50:56 status installed libreoffice-gnome:amd64 1:6.4.7-0ubuntu0.20.04.1
2021-04-15 17:50:57 trigproc gnome-menus:amd64 3.36.0-1ubuntu1 <none>
2021-04-15 17:50:57 status half-configured gnome-menus:amd64 3.36.0-1ubuntu1
2021-04-15 17:50:57 status installed gnome-menus:amd64 3.36.0-1ubuntu1
2021-04-15 18:00:30 status triggers-pending gnome-menus:amd64 3.36.0-1ubuntu1
2021-04-15 18:00:30 trigproc gnome-menus:amd64 3.36.0-1ubuntu1 <none>
2021-04-15 18:00:30 status half-configured gnome-menus:amd64 3.36.0-1ubuntu1
2021-04-15 18:00:30 status installed gnome-menus:amd64 3.36.0-1ubuntu1

ProblemType: Crash
DistroRelease: Ubuntu 20.04
Package: gnome-shell 3.36.7-0ubuntu0.20.04.1
ProcVersionSignature: Ubuntu 5.8.0-49.55~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-49-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
AssertionMessage: gnome-shell: ../../src/xcb_io.c:260: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.
CasperMD5CheckResult: skip
CrashCounter: 1
CurrentDesktop: ubuntu:GNOME
Date: Thu Apr 15 22:04:15 2021
DisplayManager: gdm3
ExecutablePath: /usr/bin/gnome-shell
ExecutableTimestamp: 1608008084
InstallationDate: Installed on 2021-01-17 (88 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
ProcCmdline: /usr/bin/gnome-shell
ProcCwd: /home/freekostageo
RelatedPackageVersions: mutter-common 3.36.7+git20201123-0.20.04.1
Signal: 6
SourcePackage: gnome-shell
StacktraceTop:
 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
 __GI_abort () at abort.c:79
 __assert_fail_base (fmt=0x7feadaaeb588 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=0x7feada528858 "!xcb_xlib_threads_sequence_lost", file=0x7feada5286c3 "../../src/xcb_io.c", line=260, function=<optimized out>) at assert.c:92
 __GI___assert_fail (assertion=0x7feada528858 "!xcb_xlib_threads_sequence_lost", file=0x7feada5286c3 "../../src/xcb_io.c", line=260, function=0x7feada528b10 "poll_for_event") at assert.c:101
 ?? () from /lib/x86_64-linux-gnu/libX11.so.6
Title: gnome-shell assert failure: gnome-shell: ../../src/xcb_io.c:260: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed.
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip docker lpadmin lxd plugdev sambashare sudo
modified.conffile..etc.xdg.autostart.gnome-shell-overrides-migration.desktop: [modified]
mtime.conffile..etc.xdg.autostart.gnome-shell-overrides-migration.desktop: 2021-01-28T02:14:06.107431
separator:

[Kostas Vlachos (19-koster)]

UPDATE 1:
My issue started on 15-04-2021 after an update (see log of updated packages). Until today, I worked under the `Wayland login` solution.

[Kostas Vlachos (19-koster)]

UPDATE 2:
Today, 24-04-2021 I did the new updates (see log of newly updated packages) and just tried to login normally as before, and it seems the the issue has been solved.

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1886059, so it 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. Feel free to continue to report any other bugs you may find.