Re: [PATCH] rtw89: use flexible array member in rtw89_btc_btf_tlv

[Gustavo A. R. Silva]

On 5/23/23 05:32, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> struct rtw89_btc_btf_tlv contains a one-byte member that is intended as a
> flexible array:
>
> In function 'fortify_memcpy_chk',
>      inlined from '_append_tdma' at drivers/net/wireless/realtek/rtw89/coex.c:1579:3:
> include/linux/fortify-string.h:583:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
>    583 |                         __write_overflow_field(p_size_field, size);
>        |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Make this actually use a flexible array to let the compiler understand.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

Thanks!
--
Gustavo

> ---
>   drivers/net/wireless/realtek/rtw89/coex.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/realtek/rtw89/coex.c b/drivers/net/wireless/realtek/rtw89/coex.c
> index 3a586a971e8f..bda0e1e99a8c 100644
> --- a/drivers/net/wireless/realtek/rtw89/coex.c
> +++ b/drivers/net/wireless/realtek/rtw89/coex.c
> @@ -206,7 +206,7 @@ static const struct rtw89_btc_ver rtw89_btc_ver_defs[] = {
>   struct rtw89_btc_btf_tlv {
>   	u8 type;
>   	u8 len;
> -	u8 val[1];
> +	u8 val[];
>   } __packed;
>   
>   enum btc_btf_set_report_en {