Re: [PATCH] hugetlb/cgroup: Fix copy/paste array assignment

[Mina Almasry <almasrymina@google.com>]

On Thu, Dec 2, 2021 at 10:56 PM Kees Cook <keescook@chromium.org> wrote:
>
> Fix mismatched array assignment, reported by an -Warray-bounds build:
>
> mm/hugetlb_cgroup.c: In function '__hugetlb_cgroup_file_legacy_init':
> mm/hugetlb_cgroup.c:850:35: error: array subscript 8 is above array bounds of 'struct cftype[8]' [-Werror=array-bounds ]
>   850 |         cft = &h->cgroup_files_dfl[8];
>       |                ~~~~~~~~~~~~~~~~~~~^~~
> In file included from mm/hugetlb_cgroup.c:23:
> ./include/linux/hugetlb.h:625:23: note: while referencing 'cgroup_files_dfl'
>   625 |         struct cftype cgroup_files_dfl[8];
>       |                       ^~~~~~~~~~~~~~~~
>
> Fixes: e45f4726bcad ("hugetlb: add hugetlb.*.numa_stat file")
> Signed-off-by: Kees Cook <keescook@chromium.org>

Sorry about that and thanks for the fix!

Reviewed-by: Mina Almasry <almasrymina@google.com>

> ---
>  mm/hugetlb_cgroup.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> index 9eebe8df3c39..f9942841df18 100644
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -847,7 +847,7 @@ static void __init __hugetlb_cgroup_file_legacy_init(int idx)
>         cft->read_u64 = hugetlb_cgroup_read_u64;
>
>         /* Add the numa stat file */
> -       cft = &h->cgroup_files_dfl[8];
> +       cft = &h->cgroup_files_legacy[8];
>         snprintf(cft->name, MAX_CFTYPE_NAME, "%s.numa_stat", buf);
>         cft->private = MEMFILE_PRIVATE(idx, 1);
>         cft->seq_show = hugetlb_cgroup_read_numa_stat;
> --
> 2.30.2
>