Skip to main content

Race condition; mutual exclusion requirements

Short answer

A race condition occurs when the final result of concurrent shared data access depends on process scheduling order. Mutual exclusion guarantees that at most one process enters its critical region at a time. Any solution must provide mutual exclusion, progress (a process outside its critical section cannot prevent others from entering), and bounded waiting (no process waits indefinitely).

What is race condition and Mutual Exclusion? List the requirements that a solution to solve race condition should satisfy.

Race condition

A race condition occurs when two or more processes access and modify shared data concurrently and the outcome depends on the order of execution. Example: two processes doing x = x + 1 on a shared x = 5 may both read 5 and both write 6, instead of 7.

Mutual exclusion

Mutual exclusion is the guarantee that when one process is executing in its critical section (the code using shared data), no other process can execute in its critical section. It is the way to prevent race conditions.

Requirements of a good solution (Tanenbaum's four conditions)

  1. Mutual exclusion: no two processes may be inside their critical regions at the same time.
  2. No assumptions about speed or number of CPUs: the solution must not depend on relative process speeds.
  3. Progress: no process running outside its critical region may block another process from entering.
  4. Bounded waiting (no starvation): no process should wait forever to enter its critical region.

(Silberschatz states these as mutual exclusion, progress and bounded waiting.)

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Operating System chapter 3 questions →