Re: [PATCH] scsi: pm80xx: Add __nonstring annotations for unterminated strings

[James Bottomley]

On Mon, 2025-03-10 at 15:25 -0700, Kees Cook wrote:
> When a character array without a terminating NUL character has a
> static
> initializer, GCC 15's -Wunterminated-string-initialization will only
> warn if the array lacks the "nonstring" attribute[1]. Mark the arrays
> with __nonstring to and correctly identify the char array as "not a C
> string" and thereby eliminate the warning.
> 
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
> Cc: Jack Wang <jinpu.wang@xxxxxxxxxxxxxxx>
> Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
> Cc: linux-scsi@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <kees@xxxxxxxxxx>
> ---
>  drivers/scsi/pm8001/pm8001_ctl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/pm8001/pm8001_ctl.c
> b/drivers/scsi/pm8001/pm8001_ctl.c
> index 85ff95c6543a..7618f9cc9986 100644
> --- a/drivers/scsi/pm8001/pm8001_ctl.c
> +++ b/drivers/scsi/pm8001/pm8001_ctl.c
> @@ -644,7 +644,7 @@ static DEVICE_ATTR(gsm_log, S_IRUGO,
> pm8001_ctl_gsm_log_show, NULL);
>  #define FLASH_CMD_SET_NVMD    0x02
>  
>  struct flash_command {
> -     u8      command[8];
> +     u8      command[8] __nonstring;

This looks a bit suboptimal ... is there anywhere in the kernel u8[] is
actually used for real strings?  In which case it would seem the better
place to put the annotation is in the typedef for u8 arrays.

Regards,

James