Re: [PATCH net-next] selftests: net: tcp_ao: make the netstat column pointer const

[Dmitry Safonov]

On Tue, 3 Nov 2026 at 16:54, Sasha Levin <sashal@xxxxxxxxxx> wrote:
>
> lookup_get_column() stores the result of strchr() on a const string in
> a plain char pointer. Since glibc 2.43, strchr() returns a const char
> pointer for a const argument when C23 features are enabled, as they
> are with _GNU_SOURCE, so gcc and clang warn:
>
>   lib/proc.c:61:16: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
>
> The pointer is only used to compute the length, so make it const.
>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>


Acked-by: Dmitry Safonov <0x7f454c46@xxxxxxxxx>

Thanks!

> ---
> Found with gcc 16 and clang 21 on glibc 2.43; KernelCI's gcc 15 builds
> show the same warning.
>
>  tools/testing/selftests/net/tcp_ao/lib/proc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/net/tcp_ao/lib/proc.c b/tools/testing/selftests/net/tcp_ao/lib/proc.c
> index 8b984fa042869..50062b527a393 100644
> --- a/tools/testing/selftests/net/tcp_ao/lib/proc.c
> +++ b/tools/testing/selftests/net/tcp_ao/lib/proc.c
> @@ -56,7 +56,7 @@ static struct netstat *lookup_get(struct netstat *ns,
>
>  static struct netstat *lookup_get_column(struct netstat *ns, const char *line)
>  {
> -       char *column;
> +       const char *column;
>
>         column = strchr(line, ':');
>         if (!column)
> --
> 2.53.0
>