[alsa-devel] [PATCH] ASoC: Amstrad Delta: fix NULL pointer dereference

[Janusz Krzysztofik]

It looks like the .card member of the snd_soc_pcm_runtime structure 
pointed to by the snd_soc_dai_link.init() argument is no longer 
initialized before the function being called. As the Amstrad Delta sound 
card driver was making use of it for locating its snd_soc_card 
structure, this resulted in actual or potential NULL pointer 
dereferences.

Since the structure in question is local to the driver, its address can 
be referred directly instead of trying to derive it from the function 
argument. Fix it.

Created and tested against linux-2.6.38-rc2

Signed-off-by: Janusz Krzysztofik <jkrzyszt at tis.icnet.pl>
---
Please consider queuing this patch for the current rc cycle.

 sound/soc/omap/ams-delta.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- git/sound/soc/omap/ams-delta.c.orig	2011-01-31 19:49:29.000000000 +0100
+++ git/sound/soc/omap/ams-delta.c	2011-02-01 17:54:22.000000000 +0100
@@ -492,12 +492,14 @@ static void ams_delta_shutdown(struct sn
  * Card initialization
  */
 
+static struct snd_soc_card ams_delta_audio_card;
+
 static int ams_delta_cx20442_init(struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_soc_codec *codec = rtd->codec;
 	struct snd_soc_dapm_context *dapm = &codec->dapm;
 	struct snd_soc_dai *codec_dai = rtd->codec_dai;
-	struct snd_soc_card *card = rtd->card;
+	struct snd_soc_card *card = &ams_delta_audio_card;
 	int ret;
 	/* Codec is ready, now add/activate board specific controls */