The four conditions (mutual exclusion, hold and wait, no pre-emption and circular wait) are necessary for a resource deadlock to occur. Give an example to show that these conditions are not sufficient...

The four conditions (mutual exclusion, hold and wait, no pre-emption and circular wait) are necessary for a resource deadlock to occur. Give an example to show that these conditions are not sufficient for a resource deadlock to occur. When are these conditions sufficient for a resource deadlock to occur? Use a resource allocation graph to illustrate your answer