Abstract:  It is very difficult to find the root cause of a system failure caused by memory exception, partly because the system failure symptoms are quite far from the real errors. In addition, a memory error often causes the whole system crash, such as avionics system, which would cause the crash of the aircraft or human casualty. Therefore as for safety critical system, the memory analysis is crucial. On the other side, compared with other memory space, stack itself is dynamic; meanwhile the dynamic scheduling and the object-code-based analysis enlarge the difficulty of stack analysis as well. Starting with the necessary of stack analysis, this paper proposes a stack analysis combining with interrupt preemption graph. Based on this theory, some suggestions are given for the safety critical system to guarantee the determination of the worst case stack depth. And then, as a real case, this paper conducts the stack analysis for a safety critical system FCOS. The process and result are mentioned also.

Key words: safety critical system, interrupt preemption graph, stack analysis, real-time operating system