Re: [bug report] ASoC: Intel: cht_bsw_rt5645: Set card.components string

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

On Mon, Jul 22, 2024 at 04:06:58PM +0200, Pierre-Louis Bossart wrote:
> Thanks Dan for the report.
> 
> 
> > Commit f87b4402163b ("ASoC: Intel: cht_bsw_rt5645: Set
> > card.components string") from Nov 26, 2023 (linux-next), leads to the
> > following Smatch static checker warning:
> > 
> > 	sound/soc/intel/boards/cht_bsw_rt5645.c:587 snd_cht_mc_probe()
> > 	error: we previously assumed 'adev' could be null (see line 581)
> > 
> > sound/soc/intel/boards/cht_bsw_rt5645.c
> >     570         /* set correct codec name */
> >     571         for (i = 0; i < ARRAY_SIZE(cht_dailink); i++)
> >     572                 if (cht_dailink[i].codecs->name &&
> >     573                     !strcmp(cht_dailink[i].codecs->name,
> >     574                             "i2c-10EC5645:00")) {
> >     575                         dai_index = i;
> >     576                         break;
> >     577                 }
> >     578 
> >     579         /* fixup codec name based on HID */
> >     580         adev = acpi_dev_get_first_match_dev(mach->id, NULL, -1);
> >     581         if (adev) {
> >                     ^^^^
> > The old code assumes adev can be NULL
> > 
> >     582                 snprintf(cht_rt5645_codec_name, sizeof(cht_rt5645_codec_name),
> >     583                          "i2c-%s", acpi_dev_name(adev));
> >     584                 cht_dailink[dai_index].codecs->name = cht_rt5645_codec_name;
> >     585         }
> >     586         /* acpi_get_first_physical_node() returns a borrowed ref, no need to deref */
> > --> 587         codec_dev = acpi_get_first_physical_node(adev);
> >                                                          ^^^^
> > Unchecked dereference
> 
> This looks like a problem in multiple machine drivers sharing similar
> code, if we want to consistently check the output we probably need
> something like https://github.com/thesofproject/linux/pull/5117 ?
> 

These are actually Smatch warnings, not Sparse warnings btw.  (Smatch
uses Sparse as a parser.  Everyone gets them mixed up).

regards,
dan carpenter