Re: [PATCH] ASoC: rsnd: fix usrcnt decrementing bug

From: Andrzej Hajda
Date: Thu Dec 24 2015 - 00:57:37 EST


On 12/24/2015 01:04 AM, Kuninori Morimoto wrote:
> Hi Andrzej
>
>> Field usrcnt is unsigned so it cannot be lesser than zero.
>>
>> The problem has been detected using proposed semantic patch
>> scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1].
>>
>> [1]: http://permalink.gmane.org/gmane.linux.kernel/2038576
>>
>> Signed-off-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
>> ---
> Thank you for your patch. good catch !
> I noticed current error case is not good for ssi.c
> Can you agree below ?
Yes, of course.

Regards
Andrzej
>
> ---------
> diff --git a/sound/soc/sh/rcar/ssi.c b/sound/soc/sh/rcar/ssi.c
> index 7db05fd..e519e30 100644
> --- a/sound/soc/sh/rcar/ssi.c
> +++ b/sound/soc/sh/rcar/ssi.c
> @@ -403,6 +403,12 @@ static int rsnd_ssi_quit(struct rsnd_mod *mod,
> struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
> struct device *dev = rsnd_priv_to_dev(priv);
>
> + if (!ssi->usrcnt) {
> + dev_err(dev, "%s[%d] usrcnt error\n",
> + rsnd_mod_name(mod), rsnd_mod_id(mod));
> + return -EIO;
> + }
> +
> if (rsnd_ssi_is_parent(mod, io))
> goto rsnd_ssi_quit_end;
>
> @@ -422,10 +428,6 @@ rsnd_ssi_quit_end:
>
> ssi->usrcnt--;
>
> - if (ssi->usrcnt < 0)
> - dev_err(dev, "%s[%d] usrcnt error\n",
> - rsnd_mod_name(mod), rsnd_mod_id(mod));
> -
> return 0;
> }
>
> ---------
>
>
> Best regards
> ---
> Kuninori Morimoto
>
>

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