Re: [PATCH] x86/csum: Add KASAN/KCSAN instrumentation

[Dmitry Vyukov]

On Wed, 26 Jan 2022 at 18:48, Jann Horn <jannh@xxxxxxxxxx> wrote:
> > > In the optimized X86 version of the copy-with-checksum helpers, use
> > > instrument_*() before accessing buffers from assembly code so that KASAN
> > > and KCSAN don't have blind spots there.
> [...]
> > Can these potentially be called with KERNEL_DS as in some compat
> > syscalls? If so it's better to use instrument_copy_to/from_user.
> > Or probably it's better to use them anyway b/c we also want to know
> > about user accesses for uaccess logging and maybe other things.
>
> Christoph Hellwig has basically eradicated KERNEL_DS. :)
>
> In particular, on X86, set_fs(KERNEL_DS) doesn't really do anything
> anymore since commit 47058bb54b579 ("x86: remove address space
> overrides using set_fs()").

That's good!

But still need this for uaccess logging.