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).
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.