[PATCH 09/16] ASoC: cs42l42: Prevent NULL pointer deref in interrupt handler

From: Richard Fitzgerald <rf@opensource.cirrus.com>
To: <broonie@kernel.org>
Cc: <alsa-devel@alsa-project.org>, <linux-kernel@vger.kernel.org>,
	<patches@opensource.cirrus.com>,
	Richard Fitzgerald <rf@opensource.cirrus.com>
Subject: [PATCH 09/16] ASoC: cs42l42: Prevent NULL pointer deref in interrupt handler
Date: Fri, 15 Oct 2021 14:36:12 +0100	[thread overview]
Message-ID: <20211015133619.4698-10-rf@opensource.cirrus.com> (raw)
In-Reply-To: <20211015133619.4698-1-rf@opensource.cirrus.com>

The interrupt handling code was getting the struct device* from a
struct snd_soc_component* stored in struct cs42l42_private. If the
interrupt was asserted before ASoC calls component_probe() the
snd_soc_component* will be NULL.

The stored snd_soc_component* is not actually used for anything other
than indirectly getting the struct device*. Remove it, and store the
struct device* in struct cs42l42_private.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
 sound/soc/codecs/cs42l42.c | 28 +++++++++-------------------
 sound/soc/codecs/cs42l42.h |  2 +-
 2 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/sound/soc/codecs/cs42l42.c b/sound/soc/codecs/cs42l42.c
index cf1f68474d21..174f738e9e5a 100644
--- a/sound/soc/codecs/cs42l42.c
+++ b/sound/soc/codecs/cs42l42.c
@@ -506,17 +506,7 @@ static int cs42l42_set_jack(struct snd_soc_component *component, struct snd_soc_
 	return 0;
 }
 
-static int cs42l42_component_probe(struct snd_soc_component *component)
-{
-	struct cs42l42_private *cs42l42 = snd_soc_component_get_drvdata(component);
-
-	cs42l42->component = component;
-
-	return 0;
-}
-
 static const struct snd_soc_component_driver soc_component_dev_cs42l42 = {
-	.probe			= cs42l42_component_probe,
 	.set_jack		= cs42l42_set_jack,
 	.dapm_widgets		= cs42l42_dapm_widgets,
 	.num_dapm_widgets	= ARRAY_SIZE(cs42l42_dapm_widgets),
@@ -1168,7 +1158,7 @@ static void cs42l42_process_hs_type_detect(struct cs42l42_private *cs42l42)
 	 */
 	if (cs42l42->hs_type == CS42L42_PLUG_INVALID ||
 		cs42l42->hs_type == CS42L42_PLUG_HEADPHONE) {
-		dev_dbg(cs42l42->component->dev, "Running Manual Detection Fallback\n");
+		dev_dbg(cs42l42->dev, "Running Manual Detection Fallback\n");
 		cs42l42_manual_hs_type_detect(cs42l42);
 	}
 
@@ -1467,19 +1457,19 @@ static int cs42l42_handle_button_press(struct cs42l42_private *cs42l42)
 	switch (bias_level) {
 	case 1: /* Function C button press */
 		bias_level = SND_JACK_BTN_2;
-		dev_dbg(cs42l42->component->dev, "Function C button press\n");
+		dev_dbg(cs42l42->dev, "Function C button press\n");
 		break;
 	case 2: /* Function B button press */
 		bias_level = SND_JACK_BTN_1;
-		dev_dbg(cs42l42->component->dev, "Function B button press\n");
+		dev_dbg(cs42l42->dev, "Function B button press\n");
 		break;
 	case 3: /* Function D button press */
 		bias_level = SND_JACK_BTN_3;
-		dev_dbg(cs42l42->component->dev, "Function D button press\n");
+		dev_dbg(cs42l42->dev, "Function D button press\n");
 		break;
 	case 4: /* Function A button press */
 		bias_level = SND_JACK_BTN_0;
-		dev_dbg(cs42l42->component->dev, "Function A button press\n");
+		dev_dbg(cs42l42->dev, "Function A button press\n");
 		break;
 	default:
 		bias_level = 0;
@@ -1553,7 +1543,6 @@ static const struct cs42l42_irq_params irq_params_table[] = {
 static irqreturn_t cs42l42_irq_thread(int irq, void *data)
 {
 	struct cs42l42_private *cs42l42 = (struct cs42l42_private *)data;
-	struct snd_soc_component *component = cs42l42->component;
 	unsigned int stickies[12];
 	unsigned int masks[12];
 	unsigned int current_plug_status;
@@ -1600,7 +1589,7 @@ static irqreturn_t cs42l42_irq_thread(int irq, void *data)
 			default:
 				break;
 			}
-			dev_dbg(component->dev, "Auto detect done (%d)\n", cs42l42->hs_type);
+			dev_dbg(cs42l42->dev, "Auto detect done (%d)\n", cs42l42->hs_type);
 		}
 	}
 
@@ -1634,7 +1623,7 @@ static irqreturn_t cs42l42_irq_thread(int irq, void *data)
 						    SND_JACK_BTN_0 | SND_JACK_BTN_1 |
 						    SND_JACK_BTN_2 | SND_JACK_BTN_3);
 
-				dev_dbg(component->dev, "Unplug event\n");
+				dev_dbg(cs42l42->dev, "Unplug event\n");
 			}
 			break;
 
@@ -1650,7 +1639,7 @@ static irqreturn_t cs42l42_irq_thread(int irq, void *data)
 			CS42L42_M_HSBIAS_HIZ_MASK)) {
 
 			if (current_button_status & CS42L42_M_DETECT_TF_MASK) {
-				dev_dbg(component->dev, "Button released\n");
+				dev_dbg(cs42l42->dev, "Button released\n");
 				report = 0;
 			} else if (current_button_status & CS42L42_M_DETECT_FT_MASK) {
 				report = cs42l42_handle_button_press(cs42l42);
@@ -2004,6 +1993,7 @@ static int cs42l42_i2c_probe(struct i2c_client *i2c_client,
 	if (!cs42l42)
 		return -ENOMEM;
 
+	cs42l42->dev = &i2c_client->dev;
 	i2c_set_clientdata(i2c_client, cs42l42);
 
 	cs42l42->regmap = devm_regmap_init_i2c(i2c_client, &cs42l42_regmap);
diff --git a/sound/soc/codecs/cs42l42.h b/sound/soc/codecs/cs42l42.h
index 2343213d0cdb..d30643398084 100644
--- a/sound/soc/codecs/cs42l42.h
+++ b/sound/soc/codecs/cs42l42.h
@@ -831,7 +831,7 @@ static const char *const cs42l42_supply_names[CS42L42_NUM_SUPPLIES] = {
 
 struct  cs42l42_private {
 	struct regmap *regmap;
-	struct snd_soc_component *component;
+	struct device *dev;
 	struct regulator_bulk_data supplies[CS42L42_NUM_SUPPLIES];
 	struct gpio_desc *reset_gpio;
 	struct completion pdn_done;
-- 
2.11.0

