Re: Build regressions/improvements in v6.8-rc2

[Guenter Roeck]

On 1/29/24 23:49, Helge Deller wrote:
> On 1/29/24 15:58, Guenter Roeck wrote:
> > On 1/29/24 03:06, Geert Uytterhoeven wrote:
> > [ ... ]
> > > parisc-gcc1[23]/parisc-{allmod,def}config
> > >
> > >    + /kisskb/src/drivers/hwmon/pc87360.c: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]:  => 383:51
> >
> > The "fix" for this problem would be similar to commit 4265eb062a73 ("hwmon: (pc87360)
> > Bounds check data->innr usage"). The change would be something like
> >
> > -               for (i = 0; i < data->tempnr; i++) {
> > +               for (i = 0; i < min(data->tempnr, ARRAY_SIZE(data->temp_max)); i++) {
> >
> > but that would be purely random because the loop accesses several arrays
> > indexed with i, and tempnr is never >= ARRAY_SIZE(data->temp_max).
> > I kind of resist making such changes to the code just because the compiler
> > is clueless.
>
> I agree with your analysis.
> But I'm wondering why this warning just seem to appear on parisc.
> I would expect gcc on other platforms to complain as well ?!?

I have seen that problem before, where specifically gcc for x86 doesn't even
generate warnings for really problematic code but gcc for other architectures
does. I never found out what causes this. Don't ask me for examples, I didn't
write it down, forgot specifics, and just accepted it as "one of those things".

Guenter