Finding DU-Paths for Testing of Multi-Tasking Real-Time Systems using WCET Analysis

Memory corruption is one of the most common software failures. For sequential software and multi- tasking software with synchronized data accesses, it has been shown that program faults causing memory cor- ruption can be detected by analyzing the relations be- tween defines and uses of variables (DU-based testing). However, such methods are insufficient in preemptive systems, since they lack the ability to detect inter-task shared variable dependencies. In this paper, we propose the use of a system level shared variable DU analy- sis of preemptive multi-tasking real-time software. By deriving temporal attributes of each access to shared data using WCET analysis, and combining this infor- mation with the real-time schedule information, our method also detects inter-task shared variable depen- dencies. The paper also describes how we extended the SWEET tool to derive these temporal attributes.