On 2/22/19 4:53 AM, Andrey Konovalov wrote: > The following testing approaches has been taken to find potential issues > with user pointer untagging: > > 1. Static testing (with sparse [3] and separately with a custom static > analyzer based on Clang) to track casts of __user pointers to integer > types to find places where untagging needs to be done. First of all, it's really cool that you took this approach. Sounds like there was a lot of systematic work to fix up the sites in the existing codebase. But, isn't this a _bit_ fragile going forward? Folks can't just "make sparse" to find issues with missing untags. This seems like something where we would ideally add an __tagged annotation (or something) to the source tree and then have sparse rules that can look for missed untags.