Deadlock occurrence

Question

Clarify condition for deadlock occurrence?

Answer 1

Deadlock can take place if four conditions hold simultaneously.

Mutual exclusion:

At a time only one process can use a resource.

Hold and wait:

A process holding at least one resource is waiting to get additional resources held by other processes.

No preemption:

A resource can be released only after that process has completed its task.

Circular wait:

There exists a set {P0, P1, ?, P0} of waiting processes in such manner that P0 is waiting for a resource which is held by P1, P1 is waiting for a resource which is held by P 2, Pn1 is waiting for a resource which is held by Pn, and P0 is waiting for a resource that is held by P0.