Everyone Asleep

A one-slot bounded buffer with one producer and two consumers, sharing a single condition variable. Both waits are while loops, so a woken thread always rechecks before proceeding:

void *producer(void *arg) {
    for (int i = 0; i < loops; i++) {
        Mutex_lock(&mutex);            // p1
        while (count == 1)             // p2
            Cond_wait(&cond, &mutex);  // p3
        put(i);                        // p4
        Cond_signal(&cond);            // p5
        Mutex_unlock(&mutex);          // p6
    }
}

void *consumer(void *arg) {
    for (int i = 0; i < loops; i++) {
        Mutex_lock(&mutex);            // c1
        while (count == 0)             // c2
            Cond_wait(&cond, &mutex);  // c3
        int tmp = get();               // c4
        Cond_signal(&cond);            // c5
        Mutex_unlock(&mutex);          // c6
    }
}

The assertion inside get() never fires now, but the program still hangs, with all three threads asleep in Cond_wait. Which event puts it there?