VFS is a good example of something that&#x27;s hairy and easy to introduce regressions affecting everyone. That&#x27;s why Al Viro dissects stuff in detail.<p>Most regressions are introduced in hardware drivers and those are the largest part of the kernel and the part that sees most churn. It&#x27;s great that we don&#x27;t see more regressions, actually, though the Intel DRM drivers have gotten worse in quality over the last year.