And just to ensure that this point is realized, you need to create an arbitrary rule that states how long the blocking can happen before you decide that it is "Hung". There's never going to be a magic "it's definitely hung at this point" line in the sand, but for practical purposes, you should know approximately where to create that line.

I would imagine it's better to kill and restart a process suspected of being hung, but not actually hung, than letting a process that is hung stay that way.

-Scott