Ubuntu – cupsd using 100% CPU, creating large (80GB+) error_log

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A few days ago I realized my Ubuntu machine wouldn't load after login. After some digging around on a liveCD I realized my HDD was at 100% capacity, so I deleted some large files and was able to log in. I didn't have sudo permissions any more and had to boot into recovery mode and change the sodoers file, but eventually recovered root permissions.

I then noticed my machine was a little sluggish, and top was showing cupsd using 100% CPU. I've never seen this program before but I soon realized it was a legitimate program.

I the deleted about 40GB worth of videos, only to see my drive space deplete almost instantly in front of my eyes. With a little research and intuition, I realized it might be a a log file being blown up, and sure enough ls -lh /var/log/cups/ shown me an error_log file that was 80GB+ large.

I deleted the file sudo rm -rf /var/log/cups/error_log, killed the service with sudo service cups end, and went on my business. I realized after that it would have been a good idea to check out the contents of error_log before I deleted it, but I wanted to get rid of the thing before I was locked out again.

That was yesterday. Today, I started my laptop again and saw cupsd running again at 100% cpu, and sure enough I see my disk space depleting. I stopped the service and run tail -f /var/log/cups/error_log, and there are millions of lines of this:

W [15/Jul/2015:11:23:03 -0700] Notifier for subscription 911 (dbus://) went away, retrying!
E [15/Jul/2015:11:23:03 -0700] File "/usr/lib/cups/notifier/dbus" has insecure permissions (0100777/uid=0/gid=0).

==EDIT=================================================================

ls -l /usr/lib/cups/notifier/dbus shows permissions and ownership as -rwxrwxrwx 1 root root when they should be -rwxr-xr-x 1 daemon root, as described in the comments. sudo chown root:root /usr/lib/cups/notifier/dbus also did not fix the ownership problems.

Finally I removed and reinstalled cups, but to no avail. These links were given as potentially helpful guides,(accidentally chmod -R on /,restore chown permissions) but they ultimately result in suggesting a reinstall of the OS itself.

Best Answer

For Ubuntu 15.10 what worked for me was:

sudo service cups stop
sudo rm /etc/cups/subscriptions.conf*
sudo rm -r /var/cache/cups
sudo service cups start

(If you cannot stop cups try):

ps aux | grep cups

Get process id (pid) from output and:

kill -9 (pid you have learned here)
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