Re: [Xen-devel] [PATCH][next] ALSA: xen-front: fix unsigned error check on return from to_sndif_format

[Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>]

Hi,

On May 28 2018 06:32, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> The negative error return from the call to to_sndif_format is being
> assigned to an unsigned 8 bit integer and hence the check for a negative
> value is always going to be false.  Fix this by using ret as the error
> return and hence the negative error can be detected and assign
> the u8 sndif_format to ret if there is no error.
>
> Detected by CoverityScan, CID#1469385 ("Unsigned compared against 0")
>
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
>   sound/xen/xen_snd_front_alsa.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/sound/xen/xen_snd_front_alsa.c b/sound/xen/xen_snd_front_alsa.c
> index 5041f83e98d2..5a2bd70a2fa1 100644
> --- a/sound/xen/xen_snd_front_alsa.c
> +++ b/sound/xen/xen_snd_front_alsa.c
> @@ -466,13 +466,14 @@ static int alsa_prepare(struct snd_pcm_substream 
> *substream)
>                 u8 sndif_format;
>                 int ret;
>   
> -		sndif_format = to_sndif_format(runtime->format);
> -               if (sndif_format < 0) {
> +               ret = to_sndif_format(runtime->format);
> +               if (ret < 0) {
>                         dev_err(&stream->front_info->xb_dev->dev,
>                                 "Unsupported sample format: %d\n",
>                                 runtime->format);
> -                       return sndif_format;
> +                       return ret;
>                 }
> +               sndif_format = ret;
>   
>   		ret = xen_snd_front_stream_prepare(&stream->evt_pair->req,
>                                                    &stream->sh_buf,
Indeed. A typical assignment mistake. Instead, we could change the type 
of 'sndif_format' to signed int, however in this case it's not the same 
as the third argument of xen_snd_front_stream_prepare() because it is 
'u8'. This patch looks good to me.
Reviewed-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxxx>


Regards

Takashi Sakamoto

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel