In the field of computer science, deadlock refers to a specific situation in concurrent programming, in which no progress is made and the program is locked in its current state. In most cases, this phenomenon is caused by a lack of, or mishandled, coordination between different lock objects, and it can be illustrated with the Dining Philosophers problem.

Potential approaches to preventing deadlocks from occurring include imposing an order for the lock objects and sharing non-shareable resources by ignoring lock objects. Each solution addresses one of the four Coffman conditions, and, while both solutions can successfully prevent deadlocks, each raises different, additional problems and concerns.

Connected to the concept of deadlock is livelock. In a livelock situation, processes (or threads) in the concurrent program are able to switch their states, but they simply switch back and forth infinitely, and no progress is made. In the next chapter, we will discuss another common problem in concurrent programming: starvation.