What is the difference between deadlock and a race condition?

Answer 1

Race Conditions

A race condition occurs when two threads access a shared variable at the same time. The first thread reads the variable, and the second thread reads the same value from the variable. Then the first thread and second thread perform their operations on the value, and they race to see which thread can write the value last to the shared variable. The value of the thread that writes its value last is preserved, because the thread is writing over the value that the previous thread wrote.

Deadlocks

A deadlock occurs when two threads each lock a different variable at the same time and then try to lock the variable that the other thread already locked. As a result, each thread stops executing and waits for the other thread to release the variable. Because each thread is holding the variable that the other thread wants, nothing occurs, and the threads remain deadlocked.

Answer 2

A race condition occurs when two threads attempt to write to the same memory at the same time.

A deadlock occurs when two threads try to acquire the same two locks but only acquire one. The two threads are deadlocked because they're each waiting on the other to release the other lock, which can never happen. A deadlock can also occur when a recursive function acquires a lock and then tries to invoke itself. Recursive functions must use recursive locks so they can acquire the same lock multiple times.