Edge chasing

In computer science, edge-chasing is an algorithm for deadlock detection in distributed systems.

Whenever a process "A" is blocked for some resource, a probe message is sent to all processes "A" may depend on. The probe message contains the process id of "A" along with the path that the message has followed through the distributed system. If a blocked process receives the probe it will update the path information and forward the probe to all the processes it depends on. Non-blocked processes may discard the probe.

If eventually the probe returns to process "A", there is a circular waiting loop of blocked processes, and a deadlock is detected. Efficiently detecting such cycles in the “wait-for graph” of blocked processes is an important implementation problem.