linux-kernel - Re: Re: [PATCH] ASoC: intel: Fix memleak in sst_media

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Date:   Thu, 13 Aug 2020 16:28:20 +0800 (GMT+08:00)
From:   dinghao.liu@....edu.cn
To:     "Pierre-Louis Bossart" <pierre-louis.bossart@...ux.intel.com>
Cc:     kjlu@....edu, "Cezary Rojewski" <cezary.rojewski@...el.com>,
        "Liam Girdwood" <liam.r.girdwood@...ux.intel.com>,
        "Jie Yang" <yang.jie@...ux.intel.com>,
        "Mark Brown" <broonie@...nel.org>,
        "Jaroslav Kysela" <perex@...ex.cz>,
        "Takashi Iwai" <tiwai@...e.com>,
        "Kuninori Morimoto" <kuninori.morimoto.gx@...esas.com>,
        "Ranjani Sridharan" <ranjani.sridharan@...ux.intel.com>,
        "Subhransu S. Prusty" <subhransu.s.prusty@...el.com>,
        "Vinod Koul" <vkoul@...nel.org>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org
Subject: Re: Re: [PATCH] ASoC: intel: Fix memleak in sst_media_open

 > 
> On 8/9/20 3:56 AM, Dinghao Liu wrote:
> > When power_up_sst() fails, stream needs to be freed
> > just like when try_module_get() fails. However, current
> > code is returning directly and ends up leaking memory.
> > 
> > Fixes: 0121327c1a68b ("ASoC: Intel: mfld-pcm: add control for powering up/down dsp")
> > Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
> > ---
> >   sound/soc/intel/atom/sst-mfld-platform-pcm.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/sound/soc/intel/atom/sst-mfld-platform-pcm.c b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> > index 49b9f18472bc..79fedf9e3da1 100644
> > --- a/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> > +++ b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> > @@ -330,8 +330,10 @@ static int sst_media_open(struct snd_pcm_substream *substream,
> >   	runtime->private_data = stream;
> >   
> >   	ret_val = power_up_sst(stream);
> > -	if (ret_val < 0)
> > +	if (ret_val < 0) {
> > +		kfree(stream);
> >   		return ret_val;
> > +	}
> >   
> >   	/* Make sure, that the period size is always even */
> >   	snd_pcm_hw_constraint_step(substream->runtime, 0,
> > 
> 
> Alternate suggestion to fix this, it's not great when we mix gotos and 
> returns.
> 
> diff --git a/sound/soc/intel/atom/sst-mfld-platform-pcm.c 
> b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> index 49b9f18472bc..b1cac7abdc0a 100644
> --- a/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> +++ b/sound/soc/intel/atom/sst-mfld-platform-pcm.c
> @@ -331,7 +331,7 @@ static int sst_media_open(struct snd_pcm_substream 
> *substream,
> 
>          ret_val = power_up_sst(stream);
>          if (ret_val < 0)
> -               return ret_val;
> +               goto out_power_up;
> 
>          /* Make sure, that the period size is always even */
>          snd_pcm_hw_constraint_step(substream->runtime, 0,
> @@ -340,8 +340,9 @@ static int sst_media_open(struct snd_pcm_substream 
> *substream,
>          return snd_pcm_hw_constraint_integer(runtime,
>                           SNDRV_PCM_HW_PARAM_PERIODS);
>   out_ops:
> -       kfree(stream);
>          mutex_unlock(&sst_lock);
> +out_power_up:
> +       kfree(stream);
>          return ret_val;
>   }

Thank you for your advice! This is better and I will send 
a new patch soon. 

Regards,
Dinghao