Re: [PATCH v3 0/6] Enable strict percpu address space checks

Andrew Morton
2024-12-13T03:35:43Z

On Sun, 8 Dec 2024 21:45:15 +0100 Uros Bizjak <ubizjak@gmail.com> wrote:

> Enable strict percpu address space checks via x86 named address space
> qualifiers. Percpu variables are declared in __seg_gs/__seg_fs named
> AS and kept named AS qualified until they are dereferenced via percpu
> accessor. This approach enables various compiler checks for
> cross-namespace variable assignments.
>
> Please note that current version of sparse doesn't know anything about
> __typeof_unqual__() operator. Avoid the usage of __typeof_unqual__()
> when sparse checking is active to prevent sparse errors with unknowing
> keyword. The proposed patch by Dan Carpenter to implement
> __typeof_unqual__() handling in sparse is located at:

google("what the hell is typeof_unequal") failed me.

I think it would be nice to include within the changelog (and code
comments!) an explanation-for-others of what this thing is and why
anyone would want to use it. Rather than assuming that all kernel
developers are typeof() experts!