Aspects include a computer-implemented method that includes receiving an instruction at a processor to perform an operation on a memory block having an address and accessing a state indicator by the processor without altering a value of the state indicator. The state indicator is stored in a memory location independent of the memory block, and accessing includes sending a request to an operator to return the value of the state indicator to the processor. The method also includes determining based on the value of the state indicator whether the memory block is in a pre-defined state.