On Fri 2018-03-09 10:45:16, Kees Cook wrote: > On Fri, Mar 9, 2018 at 4:50 AM, Mark Brown <broonie@xxxxxxxxxx> wrote: > > On Thu, Mar 08, 2018 at 12:06:53PM -0800, Kees Cook wrote: > > > >> If a codec is not attached to the sound soc, a NULL deref is possible as a > >> regular user in /sys. > > > > I can't parse this, sorry. What is the "sound soc"? > > SoC's sound component? I'm not sure either. :) I was just sending the > patch that I mentioned from the thread where Pavel mentioned this > Oops. > > Pavel, can you isolate the specific file that is causing the oops? > (Maybe this patch should be a WARN() instead of silent return 0, since > we still don't want to crash, but it should be considered a bug...) Crash is reproducible on linux-next on Nokia N900. But I seen hang on Nokia N9, with different kernel, that may be related. And yes, WARN() would be nicer. > >> +++ b/sound/soc/soc-core.c > >> @@ -137,6 +137,9 @@ static ssize_t soc_codec_reg_show(struct snd_soc_codec *codec, char *buf, > >> size_t total = 0; > >> loff_t p = 0; > >> > >> + if (!codec || !codec->driver) > >> + return 0; > >> + > > > > How are we managing to create a sysfs file for a CODEC which doesn't > > have a CODEC struct associated with it? That is obviously nonsensical > > and suggests we've got some more serious problem going on here - if > > there's no CODEC those sysfs attributes simply shouldn't be there. > > No idea! Hopefully Pavel has more details... Pavel probably can reproduce it... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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