[alsa-devel] [PATCH] ASoC: intel: Fix crash at suspend/resume after failed codec registration

[Guenter Roeck]

On Mon, Mar 25, 2019 at 03:05:33PM +0000, Mark Brown wrote:
> On Mon, Mar 25, 2019 at 07:21:00AM -0700, Guenter Roeck wrote:
> 
> > It is actually a bit more complicated than that. The stored pointer (drv->soc_card)
> > isn't released. The problem is that dev_get_drvdata(drv->soc_card->dev) is NULL,
> > which causes the crash. I don't think there is a UAF involved - I built the
> > test image with KASAN enabled and it did not barf at me.
> 
> What is a "UAF"?
> 

use-after-free. Sorry, I saw that term used so often recently that I somehow
thought it was common and started using it myself.

Guenter

> > Overall the implementation does seem a bit suspicious to me. I don't really
> > understand why the platform driver handles suspend/resume for the cards.
> > But that may just be my lack of understanding. However, either case, I think the
> > Haswell driver (sst-haswell-pcm.c) has a similar problem. I am also not sure if
> 
> It's certainly a bit unusual, usually the platform driver would just
> deal with suspending itself and the card driver would handle overall
> card suspension together with the core.