Re: [PATCH v2] kbuild: treat char as always unsigned

Linus Torvalds
2022-10-19T23:56:27Z

On Wed, Oct 19, 2022 at 1:30 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
>
> So let's just eliminate this particular variety of heisensign bugs
> entirely. Set `-funsigned-char` globally, so that gcc makes the type
> unsigned on all architectures.
>
> This will break things in some places and fix things in others, so this
> will likely cause a bit of churn while reconciling the type misuse.

Yeah, if we were still in the merge window, I'd probably apply this,
but as things stand, I think it should go into linux-next and cook
there for the next merge window.

Anybody willing to put this in their -next trees?

Any breakage it causes is likely going to be fairly subtle, and in
some random driver that isn't used on architectures that already have
an unsigned 'char' type.

I think the architectures with an unsigned 'char' are arm, powerpc and
s390, in all their variations (ie both 32- and 64-bit).

So all *core* code should be fine with this, but that still leaves a
lot of drivers that have likely never been tested on anything but x86,
and could just stop working.

I don't think breakage is very *likely*, but I suspect it exists.

Linus