In this section, we will discuss the most common solution to race conditions: locks. Intuitively, since the race conditions that we observed arose when multiple threads or processes accessed and wrote to a shared resource simultaneously, the key idea to solving race conditions is to isolate the executions of different threads/processes, especially when interacting with a shared resource. Specifically, we need to make sure that a thread/process can only access the shared resource after any other threads/processes interacting with the resource have finished their interactions with that resource.
With locks, we can turn a shared resource in a concurrent program into a critical section, whose integrity of data is guaranteed to be protected. A critical section guarantees the mutual exclusion of a shared resource, and cannot be accessed concurrently by multiple processes or threads; this will prevent any protected data from being...