Hazard Pointer
A lock-free memory-reclamation technique in which threads publish references to objects that must not yet be reclaimed.
Concurrency Context
A thread publishes a pointer in a hazard slot before dereferencing a shared object. A remover places the object on a retirement list and reclaims it only after no published hazard pointer protects it. This is one way to prevent use-after-free and to control ABA-related lifetime hazards in lock-free structures.
Correctness and Cost Boundary
Hazard pointers are not free of synchronization concerns. Correct publication and load ordering matter, and scanning hazard slots introduces work that grows with the number of participants and protected references.
Related Concurrency Concepts
- Lock-Free
- ABA Problem
- Epoch-Based Reclamation
- Memory Reclamation