In a software project as large and as rapidly evolving as the Linux kernel, automated testing systems are an integral component to the development process. Extensive build and regression tests can catch potential problems in changes before they appear in a stable release. Current systems, however, do not systematically incorporate the configuration system Kconfig. In this work, we present an approach to identify relationships between configuration options. These relationships allow us to find source files which might be affected by a change to a configuration option and hence require retesting. Our findings show that the majority of configuration options only affects few files, while very few options influence almost all files in the code base. We further observe that developers sometimes value usability over clean dependency modelling, leading to counterintuitive outliers in our results. CCS Concepts •Software and its engineering → Software product lines; Software defect analysis;

No abstract

No abstract

Linux is a highly configurable operating-system kernel which has been widely studied in the context of software product lines over the past years. Understanding the challenges and perils of evolving and maintaining feature models of the size of Linux is crucial to provide the right tools for development today and to direct future research. Unfortunately, previous studies show contradictory observations when analyzing the evolution of Linux feature models. We explain how peculiarities of the feature models of the Linux kernel lead to those differing observations, and show how the results can be realigned. Moreover, our findings also demonstrate that symbolic differencing on feature models used by researchers so far has limited value, depending on the use case. We show how the limitations can be addressed by means of semantic differencing, and ironically invalidate the results we sought to realign .