Faults in Patched Kernel
Résumé
Tools have been designed to detect for faults in the Linux Kernel, such as Coccinelle, Sparse, or Undertaker, and studies of their results over the vanilla tree have been published. We are interested in a specific point: since Linux distributions patch the kernel (as other software) and since those patches might target less common use cases, it may result in a lower quality assurance level and fewer bugs found. So, we ask ourselves: is there any difference between upstream and distributions' kernel from a faults point of view ? We present an existing tool, Undertaker, and detail a methodology for reliably counting bugs in patched and non-patched kernel source code, applied to vanilla and distributions' kernels (Debian, Mandriva, openSUSE). We show that the difference is negligible but in favor of patched kernels.