powerpc: io-defs.h:43:1: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]

[Arnd Bergmann]

On Tue, Apr 16, 2024, at 13:01, Arnd Bergmann wrote:
> On Tue, Apr 16, 2024, at 11:32, Naresh Kamboju wrote:
>> The Powerpc clang builds failed due to following warnings / errors on the
>> Linux next-20240416 tag.
>>
>> Powerpc:
>>  - tqm8xx_defconfig + clang-17 - Failed
>>  - allnoconfig + clang-17 - Failed
>>  - tinyconfig + clang-17 - Failed
>>
>> Reported-by: Linux Kernel Functional Testing <lkft at linaro.org>
>
> I'm not sure why this showed up now, but there is a series from
> in progress that will avoid this in the future, as the same
> issue is present on a couple of other architectures.
>

I see now, it was introduced by my patch to turn on -Wextra
by default. I had tested that patch on all architectures
with allmodconfig and defconfig, but I did not test any
powerpc configs with PCI disabled.

     Arnd