Oops! Where Did That Code Snippet Come from?

A kernel oops is an error report that logs the status of the Linux kernel at the time of a crash. Such a report can provide valuable first-hand information for a Linux kernel maintainer to conduct postmortem debugging. Recently, a repository has been created that systematically collects kernel oopses from Linux users. However, debugging based on only the information in a kernel oops is difficult. We consider the initial problem of finding the offending line, i.e., the line of source code that incurs the crash. For this, we propose a novel algorithm based on approximate sequence matching, as used in bioinformatics, to automatically pinpoint the offending line based on information about nearby machine-code instructions, as found in a kernel oops. Our algorithm achieves 92% accuracy compared to 26% for the traditional approach of using only the oops instruction pointer.