Re: Clang Build warning detected - include/linux/memremap.h:258:9: error: expression which evaluates to zero treated as a null pointer constant of type 'struct folio *' [-Werror,-Wnon-literal-null-conversion]

[Nick Desaulniers]

On Mon, Oct 24, 2022 at 9:19 PM Naresh Kamboju
<naresh.kamboju@xxxxxxxxxx> wrote:
>
> Following build warning / errors noticed while building x86_64 with clang
> on Linux next-20221025 tag.
>
> Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>

Hi Naresh,
Thanks for the report. It looks like AKPM is already aware.
https://lore.kernel.org/llvm/20221022163356.f5e08eeefe66fc71845be861@xxxxxxxxxxxxxxxxxxxx/

Naresh, for future reports, can you use our newer mailing list
<llvm@xxxxxxxxxxxxxxx> rather than our older one
(<clang-built-linux@xxxxxxxxxxxxxxxx>).  I haven't actually closed the
old one, but the new one is syndicated on lore.
https://lore.kernel.org/llvm/

>
> ## Build
> * kernel: 6.1.0-rc1
> * git: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next
> * git branch: master
> * git commit: 76cf65d1377f733af1e2a55233e3353ffa577f54
> * git describe: next-20221024
> * test details:
> https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20221024
>
> ## Test Regressions (compared to next-20221021)
> * i386, build
>   - clang-12-lkftconfig
>   - clang-13-lkftconfig
>   - clang-14-lkftconfig
>   - clang-nightly-lkftconfig
>
> * x86_64, build
>   - clang-12-lkftconfig
>   - clang-13-lkftconfig
>   - clang-14-lkftconfig
>   - clang-nightly-lkftconfig
>
>
> make --silent --keep-going --jobs=8
> O=/home/tuxbuild/.cache/tuxmake/builds/1/build LLVM=1 LLVM_IAS=1
> ARCH=x86_64 CROSS_COMPILE=x86_64-linux-gnu- HOSTCC=clang CC=clang
> In file included from arch/x86/kernel/asm-offsets.c:13:
> In file included from include/linux/suspend.h:5:
> In file included from include/linux/swap.h:9:
> In file included from include/linux/memcontrol.h:20:
> In file included from include/linux/mm.h:31:
> include/linux/memremap.h:258:9: error: expression which evaluates to
> zero treated as a null pointer constant of type 'struct folio *'
> [-Werror,-Wnon-literal-null-conversion]
>         return false;
>                ^~~~~
> 1 error generated.
> make[2]: *** [scripts/Makefile.build:118: arch/x86/kernel/asm-offsets.s] Error 1
>
>
> --
> Linaro LKFT
> https://lkft.linaro.org
>
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-- 
Thanks,
~Nick Desaulniers