[alsa-devel] [PATCH v2 1/5] ASoC: rockchip-max98090: Fix NULL pointer dereference while accessing to jack.

[Enric Balletbo i Serra]

Commit f2ed6b07645e ("ASoC: Make aux_dev more like a generic
component") caused a regression on this driver, since now a
kernel oops is seen when rockchip-mac98090 driver is loaded.

That commit changed the probing of aux_devs before checking
new DAI links, so for this driver rk_98090_headset_init is
called before rk_init and then the kernel oops due a NULL
pointer dereference inside rk_98090_headset_init function
since there is a call that tries to access the jack pointer
which has not been allocated yet.

This is the call chain that causes the crash:

 rk_98090_headset_init
   -> ts3a227e_enable_jack_detect
      -> snd_jack_set_key
 rk_init
   -> snd_soc_card_jack_new

This patch moves the new jack object creation from rk_init
to rk_98090_headset_init function making sure the jack is
created before is accessed.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo at collabora.com>
---
Changes since v1:
 - Improve log message.

 sound/soc/rockchip/rockchip_max98090.c | 50 ++++++++++++++++++----------------
 1 file changed, 27 insertions(+), 23 deletions(-)

diff --git a/sound/soc/rockchip/rockchip_max98090.c b/sound/soc/rockchip/rockchip_max98090.c
index 5436102..abb64a5 100644
--- a/sound/soc/rockchip/rockchip_max98090.c
+++ b/sound/soc/rockchip/rockchip_max98090.c
@@ -114,43 +114,27 @@ static int rk_aif1_hw_params(struct snd_pcm_substream *substream,
 	return ret;
 }
 
-static int rk_init(struct snd_soc_pcm_runtime *runtime)
-{
-	/* Enable Headset and 4 Buttons Jack detection */
-	return snd_soc_card_jack_new(runtime->card, "Headset Jack",
-			       SND_JACK_HEADSET |
-			       SND_JACK_BTN_0 | SND_JACK_BTN_1 |
-			       SND_JACK_BTN_2 | SND_JACK_BTN_3,
-			       &headset_jack,
-			       headset_jack_pins,
-			       ARRAY_SIZE(headset_jack_pins));
-}
-
-static int rk_98090_headset_init(struct snd_soc_component *component)
-{
-	return ts3a227e_enable_jack_detect(component, &headset_jack);
-}
-
 static struct snd_soc_ops rk_aif1_ops = {
 	.hw_params = rk_aif1_hw_params,
 };
 
-static struct snd_soc_aux_dev rk_98090_headset_dev = {
-	.name = "Headset Chip",
-	.init = rk_98090_headset_init,
-};
-
 static struct snd_soc_dai_link rk_dailink = {
 	.name = "max98090",
 	.stream_name = "Audio",
 	.codec_dai_name = "HiFi",
-	.init = rk_init,
 	.ops = &rk_aif1_ops,
 	/* set max98090 as slave */
 	.dai_fmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF |
 		SND_SOC_DAIFMT_CBS_CFS,
 };
 
+static int rk_98090_headset_init(struct snd_soc_component *component);
+
+static struct snd_soc_aux_dev rk_98090_headset_dev = {
+	.name = "Headset Chip",
+	.init = rk_98090_headset_init,
+};
+
 static struct snd_soc_card snd_soc_card_rk = {
 	.name = "ROCKCHIP-I2S",
 	.owner = THIS_MODULE,
@@ -166,6 +150,26 @@ static struct snd_soc_card snd_soc_card_rk = {
 	.num_controls = ARRAY_SIZE(rk_mc_controls),
 };
 
+static int rk_98090_headset_init(struct snd_soc_component *component)
+{
+	int ret;
+
+	/* Enable Headset and 4 Buttons Jack detection */
+	ret = snd_soc_card_jack_new(&snd_soc_card_rk, "Headset Jack",
+				    SND_JACK_HEADSET |
+				    SND_JACK_BTN_0 | SND_JACK_BTN_1 |
+				    SND_JACK_BTN_2 | SND_JACK_BTN_3,
+				    &headset_jack,
+				    headset_jack_pins,
+				    ARRAY_SIZE(headset_jack_pins));
+	if (ret)
+		return ret;
+
+	ret = ts3a227e_enable_jack_detect(component, &headset_jack);
+
+	return ret;
+}
+
 static int snd_rk_mc_probe(struct platform_device *pdev)
 {
 	int ret = 0;
-- 
2.1.0