Re: Patch "ASoC: topology: disable size checks for bytes_ext controls if needed" has been added to the 4.9-stable tree

[Pierre-Louis Bossart]

On 10/26/20 7:11 AM, Greg KH wrote:
> On Mon, Oct 26, 2020 at 01:53:46AM -0400, Sasha Levin wrote:
> > This is a note to let you know that I've just added the patch titled
> >
> >      ASoC: topology: disable size checks for bytes_ext controls if needed
> >
> > to the 4.9-stable tree which can be found at:
> >      http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> >
> > The filename of the patch is:
> >       asoc-topology-disable-size-checks-for-bytes_ext-cont.patch
> > and it can be found in the queue-4.9 subdirectory.
> >
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@xxxxxxxxxxxxxxx> know about it.
>
> This breaks the build, so I'm dropping it from everywhere it had
> problems.
>
> Also, why 5.4.y and not 4.19.y, but 4.14.y and 4.9.y?

Ah yes, there's a missed dependency on
fbd3eb7f66c5b ('ALSA: control: Add verification for kctl accesses')

I thought all of this was 20 years old but that commit added the option 
SND_CTL_VALIDATION which exposed the problem with this topology patch. 
Given the date (January 2020), I don't think it makes sense before 5.6?

I don't think this could have compiled prior to 5.6, I e.g. checked on 
4.14.202 and the define SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK was not defined 
either.

git grep SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK
sound/soc/soc-topology.c:                       k->access |= 
SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK;

Summary: I suggested this patch be dropped for all versions that don't 
contain fbd3eb7f66c5b. Takashi, do you concur?

Thanks for spotting this.
-Pierre