Race Conditions — When Timing Determines Correctness

Why it matters

Race conditions cause data corruption, occasional bugs, and impossible-to-reproduce incidents. Understanding them prevents these.

The architecture

Classic: shared counter incremented without lock. counter++ is read + modify + write. Two threads can both read same value, both write same value, losing one increment.

Solution: atomic increment or lock.

How it works end to end

Detection: race conditions are timing-dependent. Hard to reproduce.

Tools: ThreadSanitizer, race detectors in languages, static analysis.

Prevention: minimize shared mutable state; use immutable data; synchronize where needed.