Effective Verification of Low-Level Software with Nested Interrupts
Daniel Kroening1, Lihao Liang1, Tom Melham1, Peter Schrammel1 and Michael Tautschnig2
1University of Oxford, UK
2Queen Mary, University of London, UK
Interrupt-driven software is difficult to test and debug, especially when interrupts can be nested and subject to priorities. Interrupts can arrive at arbitrary times, leading to an explosion in the number of cases to be considered. We present a new formal approach to verifying interrupt-driven software based on symbolic execution. The approach leverages recent advances in the encoding of the execution traces of interacting, concurrent threads.We assess the performance of our method on benchmarks drawn from embedded systems code and device drivers, and experimentally compare it to conventional formal approaches that use source-to-source transformations. Our experimental results show that our method significantly outperforms conventional techniques. To the best of our knowledge, our technique is the first to demonstrate effective formal verification of low-level embedded software with nested interrupts.
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