With gnome-shell 3.36.9-0ubuntu0.20.04.2 I too see this with only the built-in "Desktop Icons", "Ubuntu AppIndicators", "Ubuntu Dock" extensions and no further extensions in ~/.local/share/gnome-shell/
$ journalctl -S -1hour | grep 'Jan 07 08:19:35' | sort | uniq -c Hint: You are currently not seeing messages from other users and the system. Users in groups 'adm', 'systemd-journal' can see all messages. Pass -q to turn off this notice. 22 Jan 07 08:19:35 LAP125300 gnome-shell[3286]: Attempting to call back into JSAPI during the sweeping phase of GC. This is most likely caused by not destroying a Clutter actor or Gtk+ widget with ::destroy signals connected, but can also be caused by using the destroy(), dispose(), or remove() vfuncs. Because it would crash the application, it has been blocked and the JS callback not invoked. 4314 Jan 07 08:19:35 LAP125300 gnome-shell[3286]: Attempting to run a JS callback during garbage collection. This is most likely caused by destroying a Clutter actor or GTK widget with ::destroy signal connected, or using the destroy(), dispose(), or remove() vfuncs. Because it would crash the application, it has been blocked. 22 Jan 07 08:19:35 LAP125300 gnome-shell[3286]: The offending callback was paint(), a vfunc. 4291 Jan 07 08:19:35 LAP125300 gnome-shell[3286]: The offending callback was SourceFunc(). 22 Jan 07 08:19:35 LAP125300 gnome-shell[3286]: The offending signal was paint on Gjs_ubuntu-dock_ubuntu_com_docking_DashToDock 0x5581d33fc7d0. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1908429 Title: gnome-shell fills syslog: Attempting to run a JS callback during garbage collection. This is most likely caused by destroying a Clutter actor or GTK widget with ::destroy signal connected, or using the destroy(), dispose(), or remove() vfuncs. Because it would crash the application, it has been blocked. The offending callback was SourceFunc(). Status in GNOME Shell: Unknown Status in gnome-shell package in Ubuntu: Confirmed Bug description: Issue is explained in detail here: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/1868 ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: gnome-shell 3.36.4-1ubuntu1~20.04.2 ProcVersionSignature: Ubuntu 5.4.0-53.59-generic 5.4.65 Uname: Linux 5.4.0-53-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.12 Architecture: amd64 CasperMD5CheckResult: skip Date: Wed Dec 16 18:56:56 2020 DisplayManager: gdm3 InstallationDate: Installed on 2020-04-01 (258 days ago) InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731) RelatedPackageVersions: mutter-common 3.36.6-1ubuntu0.20.04.2 SourcePackage: gnome-shell UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/gnome-shell/+bug/1908429/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp