WG211/M11Lawall

Automatic Generation of a Debugging Interface to the Linux Kernel by Julia Lawall

The Linux kernel does not export a stable, well-defined kernel interface, complicating the development of kernel-level services, such as device drivers and file systems. While there does exist a set of functions that are exported to external modules, these frequently change, and have implicit, ill-documented preconditions. However, no specific debugging support is provided.

We present Diagnosys, an approach to automatically constructing a debugging interface for the Linux kernel. First, a designated kernel maintainer uses Diagnosys to identify constraints on the use of the exported functions. Based on this information, service developers can then use Diagnosys to generate a debugging interface specialized to their code. When a service including this interface is tested, it records information about potential problems. This information is preserved following a kernel crash or hang. Our experiments show that the generated debugging interface provides useful log information and incurs a low performance penalty.

Joint work with Tegawend\'e F. Bissyand\'e, Laurent R\'eveill\`ere and Gilles Muller