linux-kernel - Re: [PATCH] ASoC: rsnd: don't double free kctrl

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Date:   Fri, 9 Dec 2016 00:04:23 +0000
From:   Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
To:     Colin King <colin.king@...onical.com>
CC:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, <alsa-devel@...a-project.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ASoC: rsnd: don't double free kctrl


Hi Colin

> From: Colin Ian King <colin.king@...onical.com>
> 
> On an error, snd_ctl_add already free's kctrl, so calling snd_ctl_free_one
> to free it again leads to a double free error.  Fix this by removing
> the extraneous snd_ctl_free_one call.
> 
> Issue found using static analysis with CoverityScan, CID 1372908
> 
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---

Indeed...
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>

If my memory was correct, this code was copied from somewhere...

BTW, in my opinion, function parameter automatically freed in "add" function
is a little bit strange behavior for me...

>  sound/soc/sh/rcar/core.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
> index 4bd68de..99b5b08 100644
> --- a/sound/soc/sh/rcar/core.c
> +++ b/sound/soc/sh/rcar/core.c
> @@ -1030,10 +1030,8 @@ static int __rsnd_kctrl_new(struct rsnd_mod *mod,
>  		return -ENOMEM;
>  
>  	ret = snd_ctl_add(card, kctrl);
> -	if (ret < 0) {
> -		snd_ctl_free_one(kctrl);
> +	if (ret < 0)
>  		return ret;
> -	}
>  
>  	cfg->update = update;
>  	cfg->card = card;
> -- 
> 2.10.2
>