What best describes a deadlock and a typical prevention approach?

• A. A temporary slowdown due to I/O operations.
• B. A deadlock is a set of processes each waiting for resources held by others.
• C. A security vulnerability that allows privilege escalation.
• D. A condition where a single process uses the CPU exclusively.

Answer: (C)

A deadlock happens when a set of processes are blocked because each one holds a resource and waits for another resource that another process in the set holds, creating a cycle where no one can proceed. This prevents progress and ties up resources.

A typical prevention approach is to break one of the four conditions that allow deadlock, with a common method being to avoid circular wait. For example, enforce a global resource ordering so processes must request resources in a fixed sequence, or require that all needed resources be requested at once rather than one at a time. Other prevention ideas include preempting resources from a process or aborting and restarting processes, but the key idea is to avoid the cyclic wait scenario that leads to deadlock.