Do operations using mutex have the property of thread blocking?

Yes, operations using mutexes in Go have the property of blocking execution threads. A mutex (sync.Mutex) provides mutual exclusion, meaning only one thread (goroutine) can acquire the mutex and execute the protected section of code. If another thread tries to acquire an already occupied mutex, it blocks and waits until the mutex is released.

Example:

var mu sync.Mutex

func criticalSection() {
    mu.Lock()   // acquire the mutex, block if it is busy
    defer mu.Unlock() // release the mutex
    // critical section
}

Thus, the mutex guarantees that only one thread executes the critical section at a time, blocking others until it is released.