mm: huge_memory.c:2736:31: error: variable 'page' is uninitialized when used here [-Werror,-Wuninitialized]

mm: huge_memory.c:2736:31: error: variable 'page' is uninitialized when used here [-Werror,-Wuninitialized]

[Naresh Kamboju]

The x86_64 clang builds failed on Linux next due to these warnings / errors.

Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>

Build error:
------
mm/huge_memory.c:2736:31: error: variable 'page' is uninitialized when
used here [-Werror,-Wuninitialized]
 2736 |         folio_remove_rmap_pmd(folio, page, vma);
      |                                      ^~~~
/builds/linux/mm/huge_memory.c:2700:19: note: initialize the variable
'page' to silence this warning
 2700 |         struct page *page;
      |                          ^
      |                           = NULL
1 error generated.

patch that is causing this build failures,
  mm/vmscan: avoid split lazyfree THP during shrink_folio_list()

metadata:

--
  git_describe: next-20240625
  git_repo: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next
  git_short_log: 0fc4bfab2cd4 ("Add linux-next specific files for 20240625")
  arch: x86_64
  toolchain: clang-18

Links:
 - https://storage.tuxsuite.com/public/linaro/lkft/builds/2iNfPlsMdxsqZTOC14r1xZZxq8X/
 - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240625/testrun/24448204/suite/build/test/clang-18-lkftconfig/details/

--
Linaro LKFT
https://lkft.linaro.org

Re: mm: huge_memory.c:2736:31: error: variable 'page' is uninitialized when used here [-Werror,-Wuninitialized]

[Nathan Chancellor]

Hi Naresh,

On Wed, Jun 26, 2024 at 10:14:56PM +0530, Naresh Kamboju wrote:
> The x86_64 clang builds failed on Linux next due to these warnings / errors.
> 
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> 
> Build error:
> ------
> mm/huge_memory.c:2736:31: error: variable 'page' is uninitialized when
> used here [-Werror,-Wuninitialized]
>  2736 |         folio_remove_rmap_pmd(folio, page, vma);
>       |                                      ^~~~
> /builds/linux/mm/huge_memory.c:2700:19: note: initialize the variable
> 'page' to silence this warning
>  2700 |         struct page *page;
>       |                          ^
>       |                           = NULL
> 1 error generated.
> 
> patch that is causing this build failures,
>   mm/vmscan: avoid split lazyfree THP during shrink_folio_list()

Thanks for the report. It looks like Andrew addressed this in
mm-unstable based on an earlier report (although that change might need
some more polish ;)

https://lore.kernel.org/202406260514.SLhNM9kQ-lkp@intel.com/

https://git.kernel.org/akpm/mm/c/199e6c3bd568657e85ead22d6f41c46e74ad9a75

Cheers,
Nathan