Comment 2 for bug 1711178

Seen that this morning on a fully updated artful. Shortly after boot, a gnome-software process started consuming 100% CPU and continued doing so for a few hours, after which I killed it.
I had not opened the gnome-software GUI, only applied a few updates manually with apt:

Start-Date: 2017-08-18 07:57:43
Commandline: apt dist-upgrade
Requested-By: osomon (1000)
Upgrade: lxc-common:amd64 (2.0.8-0ubuntu3, 2.0.8-0ubuntu5), exim4-base:amd64 (4.89-3ubuntu2, 4.89-5ubuntu1), libefivar1:amd64 (30-1ubuntu1, 31-1), python3-software-properties:amd64 (0.96.24.14, 0.96.24.15), python3-lxc:amd64 (2.0.8-0ubuntu3, 2.0.8-0ubuntu5), snapd:amd64 (2.27.1+17.10, 2.27.2+17.10), libefiboot1:amd64 (30-1ubuntu1, 31-1), exim4-daemon-light:amd64 (4.89-3ubuntu2, 4.89-5ubuntu1), lxc-templates:amd64 (2.0.8-0ubuntu3, 2.0.8-0ubuntu5), lxc1:amd64 (2.0.8-0ubuntu3, 2.0.8-0ubuntu5), software-properties-gtk:amd64 (0.96.24.14, 0.96.24.15), libunity-gtk2-parser0:amd64 (0.0.0+17.10.20170816-0ubuntu1, 0.0.0+17.10.20170817-0ubuntu1), lxc:amd64 (2.0.8-0ubuntu3, 2.0.8-0ubuntu5), liblxc1:amd64 (2.0.8-0ubuntu3, 2.0.8-0ubuntu5), libappstream-glib8:amd64 (0.7.1-1, 0.7.1-2), unity-gtk-module-common:amd64 (0.0.0+17.10.20170816-0ubuntu1, 0.0.0+17.10.20170817-0ubuntu1), exim4-config:amd64 (4.89-3ubuntu2, 4.89-5ubuntu1), chromium-browser:amd64 (61.0.3163.39-0ubuntu1.1381, 61.0.3163.49-0ubuntu1.1382), unity-gtk2-module:amd64 (0.0.0+17.10.20170816-0ubuntu1, 0.0.0+17.10.20170817-0ubuntu1), libunity-gtk3-parser0:amd64 (0.0.0+17.10.20170816-0ubuntu1, 0.0.0+17.10.20170817-0ubuntu1), chromium-codecs-ffmpeg-extra:amd64 (61.0.3163.39-0ubuntu1.1381, 61.0.3163.49-0ubuntu1.1382), ufw:amd64 (0.35-4, 0.35-5), exim4:amd64 (4.89-3ubuntu2, 4.89-5ubuntu1), chromium-browser-l10n:amd64 (61.0.3163.39-0ubuntu1.1381, 61.0.3163.49-0ubuntu1.1382), poppler-data:amd64 (0.4.7-8, 0.4.8-1), libsamplerate0:amd64 (0.1.8-8, 0.1.9-1), libsamplerate0:i386 (0.1.8-8, 0.1.9-1), unity-gtk3-module:amd64 (0.0.0+17.10.20170816-0ubuntu1, 0.0.0+17.10.20170817-0ubuntu1), libclutter-gtk-1.0-0:amd64 (1.8.2-2, 1.8.4-1), software-properties-common:amd64 (0.96.24.14, 0.96.24.15)
End-Date: 2017-08-18 07:58:17

Contents of syslog:

$ grep -i gnome-software /var/log/syslog
Aug 18 07:25:53 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 07:25:53 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 07:25:53 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 07:31:24 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 07:31:24 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 07:31:24 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 07:49:44 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 07:49:44 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 07:49:44 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 07:57:49 bribon gnome-software[6539]: failed to rescan: Failed to parse /usr/share/applications/chromium-browser.desktop.dpkg-new file: cannot process file of type text/plain
Aug 18 07:57:49 bribon gnome-software[6539]: failed to rescan: Failed to parse /usr/share/applications/chromium-browser.desktop.dpkg-tmp file: cannot process file of type text/plain
Aug 18 07:57:49 bribon gnome-software[6539]: failed to rescan: Failed to parse /usr/share/applications/chromium-browser.desktop file: cannot process file of type application/x-desktop
Aug 18 07:57:55 bribon gnome-software[6539]: failed to rescan: Failed to parse /usr/share/applications/software-properties-drivers.desktop file: cannot process file of type application/x-desktop
Aug 18 07:57:55 bribon gnome-software[6539]: failed to rescan: Failed to parse /usr/share/applications/software-properties-gnome.desktop file: cannot process file of type application/x-desktop
Aug 18 07:57:55 bribon gnome-software[6539]: failed to rescan: Failed to parse /usr/share/applications/software-properties-gtk.desktop file: cannot process file of type application/x-desktop
Aug 18 07:58:01 bribon gnome-software[6539]: failed to rescan: Failed to parse /usr/share/applications/bamf-2.index file: cannot process file of type text/plain
Aug 18 08:03:13 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:03:13 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:03:13 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:07:41 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:07:41 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:07:41 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:16:19 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:16:19 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:16:19 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:22:06 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:22:06 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:22:06 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:23:30 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:23:30 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:23:30 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:32:07 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:32:07 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:32:07 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:34:44 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:34:44 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:34:44 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:41:22 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:41:22 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:41:22 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:45:04 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:45:04 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:45:04 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:48:31 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:48:31 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:48:31 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:50:16 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:50:16 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:50:16 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:53:34 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 08:53:34 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:53:34 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:56:33 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 08:56:33 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 08:56:33 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 09:54:32 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 09:54:32 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 09:54:32 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 09:57:34 bribon gnome-software[6539]: no app for changed timezone@jwendell
Aug 18 09:57:34 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 09:57:34 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 09:58:28 bribon gnome-software[6539]: no app for changed <email address hidden>
Aug 18 09:58:28 bribon gnome-software[6539]: no app for changed suspend-button@laserb
Aug 18 09:58:28 bribon gnome-software[6539]: no app for changed timezone@jwendell

Note how there’s nothing from gnome-software after 09:58, yet the process continued consuming 100% CPU until around 11:15 (which is when I killed it).