gnome-shell freezes and continuously logs "JS ERROR: TypeError: null has no properties" in _addWindowEffect from vfunc_show (both in closeDialog.js)

Those log messages do sound related to the freeze since they repeat so much.

We find a large number of bugs are caused by extensions and you have a few installed:

'<email address hidden>'
'<email address hidden>'
'<email address hidden>'
'<email address hidden>'
'<email address hidden>'
'<email address hidden>'
'<email address hidden>'
'temperature@xtranophilist'

Please try uninstalling all of them (don't just disable them), and then tell us if the bug still occurs.

Strange, these two extensions('<email address hidden>',
'temperature@xtranophilist', '<email address hidden>'
) I've already uninstalled from gnome-tweaks, for a long time.
If they are available and easy to install, I think there is some problem with gnome shell extensions, it happens to many users that they can't start the desktop with any extension that doesn't work well (I can fix it because I know how to fix it, but many users, no).
The bug occurred only on one occasion, but I wanted to report it because I want to help fix bugs, if there are any.

I have this problem as well.

Virgin/Clean install of Eoan Desktop install in a KVM virtual machine.
Install package cqrlog, which has a long startup time and usually causes the "not responding" dialog to raise, but can be dismissed.

Under Eoan, the "CQRLOG is not responding" dialog cannot be dismissed - both "Force Quit" and "Wait" are greyed out and cannot be selected.

gnome-shell then runs to 100% cpu utilisation (one thread/core) and repeatedly logs:

gnome-shell[4157]: JS ERROR: TypeError: null has no properties#012_addWindowEffect@resource:///org/gnome/shell/ui/closeDialog.js:74:13#012vfunc_show@resource:///org/gnome/shell/ui/closeDialog.js:145:9

in syslog.
Killing gnome-shell clears the "not responding" dialog.

Not this is a virgin install to debug this problem, no extensions or anything else installed (except mariadb-server and cqrlog).

The bug has been reported upstream and looks like the same bug

https://gitlab.gnome.org/GNOME/gnome-shell/issues/1607

That was mentioned by someone other than the original reporter, so maybe? Maybe not.

Also note the link mentioned in comment #6 is actually Launchpad bug 1845302.

If the two bugs do share the same fix then you would find the fix in:

mutter (3.34.1+git20191022-2ubuntu1) focal; urgency=medium

Sounds related: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2467

Since Ubuntu 19.10 (eoan) has reached end of life, this can be closed.

Please see bug 1890613 for a more current discussion.

Hello! Please update the description to include the necessary SRU information [1]. Thank you!

[1] https://wiki.ubuntu.com/StableReleaseUpdates#SRU_Bug_Template

This bug was fixed in the package mutter - 3.38.3-2ubuntu1

---------------
mutter (3.38.3-2ubuntu1) hirsute; urgency=medium

  * Merge with debian, containing new upstream release (LP: #1915025)
    - Disable CRTCs when system becomes headless (LP: #1905825)
    - Fixed crash during windows unmanagement (LP: #1870822)
    - Do not handle ungrabbed events when unmanaging (LP: #1880405)
    - Downgrade assert to warning when adding window (LP: #1911921)
  * d/p/x11-Add-support-for-fractional-scaling-using-Randr.patch:
    - Refreshed
  * debian/rules: Enable remote desktop for all linux builds (LP: #1730612)

mutter (3.38.3-2) unstable; urgency=medium

  * Team upload
  * d/patches: Update to commit 3.38.3-12-g2d424a739 from gnome-3-38 branch
    - Cope with monitors with metacharacters in their EDID data
    - Don't crash if parsing monitor configuration fails
    - Don't crash if an extension tries to add the same window to a
      workspace more than once, such as auto-move-windows
    - Cope with monitor configuration changes during screencasting
    - Speed up workspace switching when many windows are open
    - Fix Xwayland windows not always appearing in the gnome-shell overview
    - Avoid warning spam and poor performance when unmanaging a window
      (probably Closes: #970295, LP: #1841774)

mutter (3.38.3-1) unstable; urgency=medium

  * Team upload
  * d/watch: Only watch for 3.38.x versions
  * New upstream release

 -- Marco Trevisan (Treviño) <email address hidden> Tue, 09 Feb 2021 04:59:11 +0100

Also seen on focal (from the log in bug 1917969).

still missing the SRU description