On Fri 2018-03-09 10:45:16, Kees Cook wrote:
On Fri, Mar 9, 2018 at 4:50 AM, Mark Brown broonie@kernel.org 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