Formal Verification of Embedded Linux Systems Using Trace-Base... Benno Bielmeier & Wolfgang Mauerer

Formal Verification of Embedded Linux Systems Using Trace-Based Models - Benno Bielmeier & Wolfgang Mauerer, Technical University of Applied Sciences Regensburg

Software for safety-critical systems must meet strict functional and temporal requirements. Since it is impossible to exhaustively test the required qualities, formal verification techniques have been devised. However, these approaches are usually only applicable to small systems, and require software architecture and development to consider verification goals from the ground up. Safety-critical systems face an increasing demand for functionality, and need to handle the associated complexity. While the desired functionalities can be satisfied by embedded Linux, established verification techniques fail for code of such magnitude. We show a semi-formal, model-based approach to derive reliable statements about the run-time characteristic of embedded Linux. Using a-priori expert knowledge, we generate a finite automaton-based effective description of safety-relevant aspects. The real-world, system-dependent behaviour of the resulting automata, in particular timing statistics for state transitions, is empirically obtained via system instrumentation. We then show how to turn this into (statistical) guarantees on their behaviour. We show how this allows to draw conclusions that can be used in certifying systems in terms of reliability, latencies, and other real-time properties.