reboot? - this is linux!

Just had a scary few minutes, this morning I was unable to logon the home mailserver (running mandriva 2010.1) across the local network - the process connected, opened up a terminal window and just hung, never getting to a prompt! Sunday lunch over, I tried opening up a term when sitting at the machine with the problems and there too, no xterm! Fortunately I was already logged in and had root (admin) access. Looking back in the logs I saw a crash in ssh (which I use to get onto the mailserver from other machines) - in ssh-block-Allow. I could understand ssh problems causing a problem with remote access - but why was local access a problem? Even a Control - C failed to interrupt whatever was running - and I could check that nothing was hogging the CPU.
I looked through any recent updates to the machine and saw nothing likely, googling only gave me my tweet for help(!) so I hurriedly connected the backup drive, did a machine backup - I was glad I already had root access and then tried a reboot. This failed to work - wouldn't shutdown with a message:

could not log bootup - already in use

so a magic key shutdown (using the sysRq key) was resorted to.
A few deep breaths later and the system rebooted and I logged in - then I realised the consequence of the ssh crash - one of the system scripts which run when you open up a terminal checks whether the machine is running ssh and, if so, asks you to unlock the key - for passwordless logins - if ssh is confused - as it evidently was - maybe that script was hanging there.
So I guess killing and restarting sshd would have avoided the reboot as to why ssh was broken that's another issue!
At least the server had been up for a month so it wasn't too unstable!