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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Cc: kbuild@lists.01.org, lkp@intel.com, kbuild-all@lists.01.org,
	linux-mm@kvack.org, broonie@kernel.org
Subject: Re: [linux-next:master 9388/11353] sound/soc/soc-compress.c:628 snd_soc_new_compress() error: we previously assumed 'codec_dai' could be null (see line 571)
Date: Wed, 9 Mar 2022 13:18:23 +0300	[thread overview]
Message-ID: <20220309101823.GS3315@kadam> (raw)
In-Reply-To: <20220309093219.1142599-1-jiasheng@iscas.ac.cn>

On Wed, Mar 09, 2022 at 05:32:19PM +0800, Jiasheng Jiang wrote:
> On Wed, Mar 09, 2022 at 01:58:04AM +0800, Dan Carpenter wrote:
> > smatch warnings:
> > sound/soc/soc-compress.c:628 snd_soc_new_compress() error: we previously assumed 'codec_dai' could be null (see line 571)
> 
> > de2c6f98817fa5d Jiasheng Jiang     2021-10-15 @571  	if (codec_dai) {
> > 
> > Can codec_dai be NULL?  This new code assumes so.
> 
> > aeb6fa0f15c71a1 Peng Donglin       2017-08-16 @628  			rtd->dai_link->stream_name, codec_dai->name, num);
> >                                                                                                     ^^^^^^^^^^^^^^^^
> > Unchecked dereference
> 
> Actually, if 'codec_dai' is NULL, the check in line 584 will fail and return -EINVAL.
> 
> a1068045883ed4a Vinod Koul         2016-01-07  584  	if (playback + capture != 1) {
> 141dfc9e3751f5f Charles Keepax     2018-01-26  585  		dev_err(rtd->card->dev,
> 141dfc9e3751f5f Charles Keepax     2018-01-26  586  			"Compress ASoC: Invalid direction for P %d, C %d\n",
> a1068045883ed4a Vinod Koul         2016-01-07  587  			playback, capture);
> a1068045883ed4a Vinod Koul         2016-01-07  588  		return -EINVAL;
> a1068045883ed4a Vinod Koul         2016-01-07  589  	}
> 

Yeah.  That's true.  Smatch tries to look at conditions and figure out
the implications but this one is too complicated.

But if codec_dai can really be NULL then it would be easier to
understand if we reversed the check on codec_dai and returned early.

	if (!codec_dai) {
		dev_err(rtd->card->dev, "Missing codec\n");
		return -EINVAL;
	}

	/* check client and interface hw capabilities */
	if (snd_soc_dai_stream_valid(codec_dai, SNDRV_PCM_STREAM_PLAYBACK) &&
	    snd_soc_dai_stream_valid(cpu_dai,   SNDRV_PCM_STREAM_PLAYBACK))
		playback = 1;

regards,
dan carpenter


  reply	other threads:[~2022-03-09 10:19 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-09  9:32 Jiasheng Jiang
2022-03-09 10:18 ` Dan Carpenter [this message]
  -- strict thread matches above, loose matches on Subject: below --
2022-03-10  1:38 Jiasheng Jiang
2022-03-08 17:58 Dan Carpenter

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