There is no progress as there is a possibility of a DEADLOCK.
I'll show how.
Suppose the buffer is empty.
Then empty=N and full=0
Suppose producer runs first and it runs till the line down(empty) and then it got preempted.
Now the consumer runs.
Mutex was initially 1
Down(Mutex) makes it 0
Down(full) suspends the consumer as full is 0
Now the producer runs again. When it executes down(mutex) it gets suspended too.
--->>Producer and consumer both are suspended-->>Deadlock---> No Progress