Abstract: Verifying operation of a data processing system. A first sequence of addressing ranges is generated for multiple requesters. Each addressing range includes a start and an end address and a respective identifying number. A second sequence of verification ranges is generated corresponding the addressing ranges of the first sequence. Each verification range includes a start and an end address and specifies at least one allowed value including each respective identifying number of all of the addressing ranges that overlap the verification range. A respective accessing activity executing on each requestor accesses each addressing range in the first sequence. The accesses include writing the respective identifying number of the addressing range to at least one address of the addressing range. A verification activity executing on a requestor reads a value from each address of each verification range of the second sequence and outputs an error message in response to the value not matching the allowed value.