It is stated in the text (exercises) that the Linux operating system does not allow a process holding a spinlock to attempt to acquire a semaphore. What is the source of this statement? What bad things could happen, which need to be avoided, if a process holding a spinlock could also try to access a semaphore (whether it gets in or not)? What is it that a process holding a spinlock cannot do, which implements the prohibition? Note that this is not the same as when a process is spinning waiting for the mutex.