Automated Testing Summit 2025

In the general case, coverage is performed by instrumenting code at relevant points and adding sections at the linker stage to maintain data being accumulated by instrumentation. This technique reduces the effects of instrumentation on runtime behavior to a practical limit. In practice, testing proceeds by running the instrumented application, and then, typically at program exit, looking for an instrumentation file that contains counters and other data generated by the instrumentation. This method of instrumentation and data collection works well for standalone applications. It presents a significant challenge when attempting to apply it to an operating system kernel like Linux. This talk will provide a detailed overview of a successful collaboration led by Steve VanderLeest, PhD, Boeing Technical Fellow, in cooperation with the University of Illinois Urbana-Champaign, to add LLVM code coverage capability to the Linux kernel. Chuck will provide additional background including details on testing and refinement efforts, demonstrate capability, and discuss the follow-on work in progress to get the capability accepted into the mainline Linux kernel.