I am bumping into desktop crashes (called login loop by many) on Ubuntu 21.04.
This started happening after an interrupted sudo apt install... session which had run 70 (very low bandwidth) hours before power outage.
Upon power restoration, I reran apt thinking the machine would be very out-of-sorts. Notably, apt proceeded based, I'm guessing, on its cache. It ran for additional time, then gave me a report which listed 9 or 10 failed packages; there were many lines preceding the failed package which seemed to indicate successful installation of the remaining packages.
After a few more invocations of apt to install the failed packages, I was relieved.
Upon rebooting, however, I was met with the desktop crash.
An answer by user10489 to this related question (Recurring problems with Login Loops ubuntu 20.10) was very thorough.
Except for the gnome-specific steps, I examined all the others. None applied.
The problem began after running the completion of apt. I don't recall whether apt prompted me to do so, but I rebooted the machine.
First on my main account... then attempting to login on my backup account (which I always create for cases just like this), leads to the same result.
SYMPTOMS When I press the last key of my password followed by enter, it proceeds as usual... Then the screen turns black, flashes a couple lines of text at top, then returns to login screen and beeps.
Lines flashed on screen:
[ 133.715541] netdata[4213]: 2021-08-30 11:50:14: netdata INFO : MAIN : CONFIG: cannot load cloud config '/var/lib/netdata/cloud.d/cloud.conf'. Running with internal defaults.
[ 134.569325] netdata[4213]: 2021-08-30 11:50:15: netdata INFO : MAIN : SIGNAL : Not enabling reaper
I am able to access the text terminals.
I created a new user... and faced the same fate.
I examined the .xsession-errors resource which consists of 131 lines.
Among the first ten lines:
/etc/X11/Xsession.d/30x11-common_xresources: line 16: has_option: command not found
/etc/X11/Xsession.d/75dbus_dbus-launch: line 9: has_option: command not found
/etc/X11/Xsession.d/90x11-common_ssh-agent: line 9: has_option: command not found
The last 11 lines
dbus-update-activation-environment: setting _=/usr/bin/dbus-update-activation-environment
dbus-update-activation-environment: warning: error sending to systemd: org.freedesktop.DBus.Error.InvalidArgs: Invalid environment assignments
Insecure $ENV{ENV} while running with -T switch at /usr/share/perl5/GnuPG/Interface.pm line 348.
Compilation failed in require at /usr/bin/monkeysphere-validation-agent line 22
BEGIN failed--compilation aborted-at /usr/bin/monkeysphere-validation-agent line 22
Use of uninitialized value $line in pattern match (m//) /usr/share/perl5/GnuPG/Interface.pm line 820.
Use of uninitialized value $a in split at /usr/share/perl5/GnuPG/Interface.pm line 834.
Use of uninitialized value $a in split at /usr/share/perl5/GnuPG/Interface.pm line 834.
GnuPG version 1.4 or 2.2+ required at (eval 191) line 55.
Compilation failed in require at /usr/bin/monkeysphere-validation-agent line 22.
BEGIN failed--compilation aborted at /usr/bin/monkeysphere-validation-agent line 22.
Nearly all of the remaining 100 lines in .xsession-errors appear to be simple log messages; none have "warning" or "error" but almost all of them relate to dbus.
My instinct is saying there's a problem with the dbus installation. On the other hand, the messages presented on the screen during the attempted logins have netdata indicated.
But I'm in a strange territory. I'm not sure what to try next. Is it dbus, netdata or something altogether different?
(UPDATE: after looking into netdata, man says it's "real-time performance monitoring." So, I highly doubt this is the problem, leaving me with dbus as my only option. It makes sense since system inter-process messaging relies on it.)
Looking in the /var/crash directory yields no help. I reviewed the directory. Tried login. Returned to review the /var/crash and no new file had been created.
A review of previous crash files were only 2 or 3 lines and had to do with autojack. (Which makes me happy to find because I lost sounds a couple weeks ago... Now, I have a lead!)
(Updated 2021-09-08)
As I continue investigating, I have found systemctl status reports "degraded." Upon review of the output from sustemctl --all list-units , I see that there are a number (38) of units 'not-found', 5 identified as "masked" and 3 marked as "failed."
cat /var/log/syslog | grep -i <searchword>and thencat /var/log/syslog.1 | grep -i <searchword>