Re: [PATCH] bpf: avoid padding in struct bpf_common_attr

[Yonghong Song <yonghong.song@linux.dev>]

On 5/19/26 1:38 PM, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Building linux/bpf.h with -Wpadded shows an unintentionally
> added portion of padding because of the 64-bit alignment:
>
> ./usr/include/linux/bpf.h:1510:1: error: padding struct size to alignment boundary with 4 bytes [-Werror=padded]
>
> Avoid this by adding explicit padding.
>
> Fixes: f28771c0691b ("bpf: Extend BPF syscall with common attributes support")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   include/uapi/linux/bpf.h | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index cc4c0b62cdfa..0f0ec00cae4a 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -1507,6 +1507,7 @@ struct bpf_common_attr {
>   	__u32 log_size;
>   	__u32 log_level;
>   	__u32 log_true_size;
> +	__u32 __pad;

Let us make it as
	__u32 :32;
?

This can avoid people to use the '__pad' name.
IIUC, typically uapi struct won't have implicit padding.

>   };
>   
>   #define BPF_OBJ_NAME_LEN 16U