ot: Linux 2.6.6 and ghost users

[Adam Myrow]

I don't know if it's more frequent in 2.6.6, but I've noticed it on
occasion in just about every Linux version I've ever used.  The problem is
that /var/run/utmp gets out of sync with reality.  I would check the
permissions and make sure that they haven't changed.  Slackware defaults
the permissions to 664 with an owner of root and group of utmp, but other
flavors of Linux may do it differently.  If you're reasonably sure that
nothing besides the kernel version has changed, it probably is some sort
of bug with kernel 2.6.6.  On the rare occasions that it has happened to
me, either rebooting, or typing "cat /dev/null >/var/run/utmp" may help.
The latter will make the system think nobody is logged in, so it's not
perfect either.