Race Conditions

• Non-determinism
  • The outcome is unpredictable and varies with different runs of the program, even if the input remains the same.
• Concurrency
  • Race conditions arise in concurrent environments where tasks are executed in parallel.
• Shared Resources
  • Access to shared resources (like global variables, static variables, or shared hardware resources) without proper synchronization is a common cause.
• Timing Sensitivity
  • The occurrence of a race condition often depends on the sequence and timing of uncontrollable events, such as the scheduling order of threads by the Operating System

#Common Scenarios Leading to Race Conditions

• Check-Then-Act Operations
  • If a thread checks a condition (like if a resource is available) and then acts on it (accesses the resource), the condition may change after the check but before the action, due to another concurrent thread.
• Read-Modify-Write Sequences
  • When multiple threads read a value from a shared variable, modify it, and then write it back, the final value may reflect only one of the modifications, losing the others.
• Improper use of Synchronization Primitives
  • Even with synchronization mechanisms in place (like Mutexes or Semaphores), incorrect usage can still lead to race conditions, such as forgetting to lock a mutex or incorrect ordering of lock acquisition.

#Prevention and Mitigation

• Mutexes, locks, and condition variables
  • Use mutexes or locks to ensure that only one thread can access a critical section of code at a time.
• Atomic Operations
  • Utilize atomic operations provided my many programming languages and frameworks that ensure a sequence of operations is treated as a single, indivisible step.
• Design Strategies
  • Architectural changes, such as reducing the sharing of mutable data between threads or using immutable data structures, can inherently prevent race conditions.