Cinnamon boots to black screen with cursor, then restarts in a loop, the logs reference systemd / dbus timeout

I've been running Linux Mint now for ~10 years after earlier forays into Gentoo, Slackware & Arch.  Back when I was a teenager and I didn't have the cash to purchase new hardware and needed to squeeze every inch of performance out of my machines, distributions which gave me fine-grained control of what was running in the kernel & user space not only gave me this last bit of performance, but also taught me a lot about running Linux & GNU in general.

Since moving over to Linux Mint, things have usually "just worked" without the need for me to actively manage my OS.  Unfortunately, computers are computers and sometimes things break.  I don't have to reboot often, though I do like to keep my machine up-to-date.  After keeping my machine up for a month or two, I noticed that suddenly I was experiencing catastrophic failure--the network was working, but Network Manager was not.  I was unable to perform many tasks on the machine, therefore, I rebooted.

The machine appeared to reboot fine, albeit taking ~5 minutes longer than normal, though once I entered into X is when I noticed that lightdm was not coming up--I would see a pointer on a black screen before X cycled into a loop, exiting to a blinking cursor and then back to the black screen with pointer.

Quickly dropping into my terminal & killing lightdm, I began reviewing the lightdm logs to see exactly where the problem lay.  I saw several lines like so:

WARNING: Failed to get list of logind seats: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'org.freedesktop.login1': timed out (service_start_timeout=25000ms)

And so:

WARNING: Error getting user list from org.freedesktop.Accounts: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'org.freedesktop.Accounts': timed out (service_start_timeout=25000ms)

Thinking possibly that a package broke my system, I proceeded to perform an apt update / apt upgrade, though while running apt I also was seeing the following suspicious error:

Error: Timeout was reached
Reading package lists... Done

Digging into my syslog also showed multiple service start failures, all pointing back to a DBus timeout:

Oct 18 16:13:14 hostname accounts-daemon[1173]: error getting polkit authority: Error initializing authority: Error calling StartServiceByName for org.freedesktop.PolicyKit1: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'org.freedesktop.PolicyKit1': timed out (service_start_timeout=25000ms)

Oct 18 16:13:14 hostname udisksd[1164]: Error initializing polkit authority: Error initializing authority: Error calling StartServiceByName for org.freedesktop.PolicyKit1: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'org.freedesktop.PolicyKit1': timed out (service_start_timeout=25000ms) (g-dbus-error-quark, 20)

Oct 18 16:13:14 hostname ModemManager[1172]: <warn>  failed to create PolicyKit authority: 'Error initializing authority: Error calling StartServiceByName for org.freedesktop.PolicyKit1: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'org.freedesktop.PolicyKit1': timed out (service_start_timeout=25000ms)'

After doing some research I came across some posts regarding the transition away from /var/run/dbus as a standalone folder, and rather a symlink to /run/dbus:

 

• https://bugs.freedesktop.org/show_bug.cgi?id=75515
• https://bugs.launchpad.net/ubuntu/+source/dbus/+bug/811441
• https://forums.gentoo.org/viewtopic-t-1090156-start-0.html 

 

Clearly, there was something wrong with my /var/run configuration--after checking, it appears that some package had replaced /var/run with a real folder--instead of a symlink to /run.

After re-creating the symlink with the following command and rebooting, everything was back to normal 🎉:

ln -s /run /var/run

Note: After writing this blog post, I realized that the root cause of the issue & the solution were clearly documented on the Linux Mint Releases & Announcements form here: https://forums.linuxmint.com/viewtopic.php?t=331605