Configuration Lifting: Verification meets Software Configuration

Configurable software is ubiquitous, and the term software product line (SPL) has been coined for it lately. It remains a challenge, however, how such software can be verified over all variants. Enumerating all variants and analyzing them individually is inefficient, as knowledge cannot be shared between analysis runs. Instead of enumeration we present a new technique called lifting that converts all variants into a meta-program, and thus facilitates the configuration-aware application of verification techniques like static analysis, model checking and deduction-based approaches. As a side-effect, lifting provides a technique for checking software feature models, which describe software variants, for consistency. We demonstrate the feasibility of our approach by checking configuration dependent hazards for the highly configurable Linux kernel which possesses several thousand of configurable features. Using our techniques, two novel bugs in the kernel configuration system were found.