Gnome shell freezes for about 1 minute after screen blanks. high disk usage

[Frank van Wensveen]

After the screen is blanked following a few minutes of inactivity, the UI freezes for about a minute as soon as the password has been entered. During this time there is a lot of harddisk I/O (close to 100%) until eventually the UI eventually unlocks and the regular desktop environment (showing windows, applications, desktop icons and what not) reappears. This happens irregularly but frequently. System is a Dell Inspiron 3576 laptop running Ubuntu 18.04.2 LTS and gnome-shell 3.28.3+git20190124-0ubuntu18.04.2.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-shell 3.28.3+git20190124-0ubuntu18.04.2
ProcVersionSignature: Ubuntu 4.15.0-50.54-generic 4.15.18
Uname: Linux 4.15.0-50-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.6
Architecture: amd64
CurrentDesktop: GNOME
Date: Thu May 23 18:17:53 2019
DisplayManager: gdm3
EcryptfsInUse: Yes
InstallationDate: Installed on 2018-05-10 (378 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[Frank van Wensveen (frankvw-temp)]

$ apt-cache policy gnome-shell
gnome-shell:
  Installed: 3.28.3+git20190124-0ubuntu18.04.2
  Candidate: 3.28.3+git20190124-0ubuntu18.04.2
  Version table:
 *** 3.28.3+git20190124-0ubuntu18.04.2 500
        500 http://us.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        500 http://us.archive.ubuntu.com/ubuntu bionic-security/main amd64 Packages
        100 /var/lib/dpkg/status
     3.28.1-0ubuntu2 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

[Sebastien Bacher (seb128)]

Thank you for your bug report, could you add your journalctl log after getting the issue?

[Daniel van Vugt (vanvugt)]

Please start by uninstalling these extensions, then reboot and tell us if the problem stops happening:

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[Daniel van Vugt (vanvugt)]

Also, to collect the log requested in comment #3, please:

1. Reproduce the problem again.

2. Run: journalctl -b0 > curjournal.txt
   and send us the file 'curjournal.txt'

[Frank van Wensveen (frankvw-temp)]

@Sebastien Bacher: journalctl output attached.

@Daniel van Vugt: I'll do so and get back to you.

[Frank van Wensveen (frankvw-temp)]

@Daniel van Vugt:

You were right; the problem appears to have been related to a shell extension, but not one of the extensions you suggested I uninstall. The cause seems to have been the "freon" extension (https://extensions.gnome.org/extension/841/freon/) which was installed but disabled. Since this extension was removed the problem has not recurred.

So this is not a Gnome3 bug and this entry can be closed as such.

Thank you for your assistance!!