Deadlock
A situation where two or more processes are each waiting for resources held by the others, causing permanent blocking.
Definition
A deadlock is a situation in concurrent computing where two or more processes are each waiting for a resource held by another process in the set, creating a circular dependency that prevents all processes from proceeding. Deadlocks require four conditions: mutual exclusion, hold and wait, no preemption, and circular wait. Prevention strategies include resource ordering, lock timeouts, and deadlock detection algorithms. Database deadlocks occur when transactions lock rows needed by each other.
Example
“Process A holds Lock 1 and waits for Lock 2; Process B holds Lock 2 and waits for Lock 1 — both are stuck permanently in a deadlock.”
Synonyms
- circular dependency
- resource lock cycle
- thread deadlock
Antonyms / Opposites
- livelock resolution
- lock-free execution
Images
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Related Terms
- thread
- mutex
- concurrency
- starvation