When restarting sshd using the /etc/rc.d/init.d/sshd script 
the restart fails when the person doing the restart is logged
in through ssh. 

In /etc/rc.d/init.d/functions the daemon() function does a check
for whether any proceses with the same executable name is 
currently running by doing:

 # See if it's already running.
        pidlist=`pidofproc $1`
        
        pid=
        for apid in $pidlist ; do
           [ -d /proc/$apid ] && pid="$pid $apid"
        done
        
        [ -n "$pid" ] && return

However, when you are logged in by ssh to the machine and you
try to restart sshd, there IS a process called /usr/sbin/sshd running
so the daemon function"returns" without actually doing anything.

I can see how this might be a good idea sometimes, however, in this
case it makes the script useless for anyone running headless boxes, 
and makes it easy to get stuck with a machine with no way to login to.
(the restart fails, but you don't notice and then logout of the one ssh
shell you currently have---then you can never login until a reboot)

I'm not sure of the best way to fix this except to remove the check and
make
individual scripts check for other running instances if they want.