My professor refuses to answer this question and I am beginning to doubt he doesn't know the answer.
I was given the following 
Suppose we have two threads running on parallel CPU's (writing and reading from same data block in RAM) First cache is in state M; the second is in an unknown state (must be in I state according to what I understood)
The question is: If BusWrite was sent from the 2nd cache, is there a possibility that the first cache is written back to RAM where it is for sure not the latest updated but the latest modified value in 2nd cache is written back to RAM?
My professor says yes, my question is why would we write unupdated data back to RAM?
