Re: Linux 5.19-rc6

[Guenter Roeck]

On 7/14/22 09:48, Linus Torvalds wrote:
> On Thu, Jul 14, 2022 at 12:23 AM Geert Uytterhoeven
> <geert@xxxxxxxxxxxxxx> wrote:
> > Oh, it's not just this one. The lists of build regressions between v5.18
> > and v5.19-rc1 [1] resp. v5.19-rc6 [2] look surprisingly similar :-(
> >
> > [1] https://lore.kernel.org/all/20220606082201.2792145-1-geert@xxxxxxxxxxxxxx
> > [2] https://lore.kernel.org/all/20220711064425.3084093-1-geert@xxxxxxxxxxxxxx
>
> Hmm.
>
> Some of them are because UM ends up defining and exposing helper
> functions like "to_phys()", which it just shouldn't do. Very generic
> name - so when some driver ends up using the same name, you get those
> errors.

We can't use virt_to_phys() and phys_to_virt() because they are defined for
the underlying architecture. Would uml_to_phys() and uml_to_virt() be
acceptable ? If so, I'll submit a patch.

> And some look positively strange. Like that
>
>    drivers/mfd/asic3.c: error: unused variable 'asic'
> [-Werror=unused-variable]:  => 941:23
>
> which is clearly used three lines later by
>
>          iounmap(asic->tmio_cnf);
>
> and I can't find any case of 'iounmap()' having been defined to an
> empty macro or anything like that to explain it. The error in
> drivers/tty/serial/sh-sci.c looks to be exactly the same issue, just
> with ioremap() instead of iounmap().
>
> It would be good to have some way to find which build/architecture it
> is, because right now it just looks bogus.
>
> Do you perhaps use some broken compiler that complains when the empty
> inline functions don't use their arguments? Because that's what those
> ioremap/iounmap() ones look like to me, but there might be some
> magical architecture / config that has issues that aren't obvious.
>
> IOW, I'd love to get those fixed, but I would also want a little bit more info.
Geert gave the necessary hint - it looks like sh-nommu used defines
for iomap() and iounmap(), which made the variable unused. According
to Geert that was fixed a couple of days ago.

Guenter