Abstract: An aspect of the invention is directed towards a data processing system and method including a transaction scheduler configured to process transactions, a tag control circuit coupled to the transaction scheduler configured to detect a fault by comparing output signals, and a controller coupled to the tag control circuit. The controller is configured to receive a transaction request identifying a transaction, generate a unique tag value for the transaction request, load the unique tag value into the transaction scheduler, determine a current unique tag value associated with the transaction being executed, and generate a fault. The system is further configured to generate fault when: (i) the current unique tag value is not found, or (ii) the transactions timeout after a predetermined number of cycles.