[PATCH 1/6] ASoC: wm8962: Fix regulator notifier and beep leaks on card re-bind

[Chancel Liu]

From: Chancel Liu <chancel.liu@xxxxxxx>

wm8962 registers its regulator disable notifiers and allocates its beep
input device from the ASoC component probe, but the associated devres
cleanup is tied to the underlying I2C device.

These resources are only leaked when the sound card is unregistered and
re-registered while the I2C device stays bound. On that path the
component probe runs again and:

- re-registers the same notifier_block on the still-registered
  regulator notifier chain, which triggers

    notifier callback wm8962_regulator_event_N already registered
    WARNING: ... at kernel/notifier.c:23 notifier_chain_register

  and corrupts the chain.

- allocates and registers a new beep input device every time while
  wm8962_free_beep() only clears the pointer, leaking the previous
  input device and its sysfs/input node.

Fix both:
- Move the regulator notifier registration to wm8962_i2c_probe() so it
  runs once per I2C device bind.

- Allocate the beep device with input_allocate_device() and pair it
  with the component lifecycle: input_free_device() on registration
  failure and input_unregister_device() in wm8962_free_beep().

Signed-off-by: Chancel Liu <chancel.liu@xxxxxxx>
---
 sound/soc/codecs/wm8962.c | 52 +++++++++++++++++++++------------------
 1 file changed, 28 insertions(+), 24 deletions(-)

diff --git a/sound/soc/codecs/wm8962.c b/sound/soc/codecs/wm8962.c
index af4716051220..ae6cc9c72439 100644
--- a/sound/soc/codecs/wm8962.c
+++ b/sound/soc/codecs/wm8962.c
@@ -3355,7 +3355,7 @@ static void wm8962_init_beep(struct snd_soc_component *component)
 	struct wm8962_priv *wm8962 = snd_soc_component_get_drvdata(component);
 	int ret;
 
-	wm8962->beep = devm_input_allocate_device(component->dev);
+	wm8962->beep = input_allocate_device();
 	if (!wm8962->beep) {
 		dev_err(component->dev, "Failed to allocate beep device\n");
 		return;
@@ -3376,8 +3376,10 @@ static void wm8962_init_beep(struct snd_soc_component *component)
 
 	ret = input_register_device(wm8962->beep);
 	if (ret != 0) {
+		input_free_device(wm8962->beep);
 		wm8962->beep = NULL;
 		dev_err(component->dev, "Failed to register beep device\n");
+		return;
 	}
 
 	ret = device_create_file(component->dev, &dev_attr_beep);
@@ -3393,7 +3395,10 @@ static void wm8962_free_beep(struct snd_soc_component *component)
 
 	device_remove_file(component->dev, &dev_attr_beep);
 	cancel_work_sync(&wm8962->beep_work);
-	wm8962->beep = NULL;
+	if (wm8962->beep) {
+		input_unregister_device(wm8962->beep);
+		wm8962->beep = NULL;
+	}
 
 	snd_soc_component_update_bits(component, WM8962_BEEP_GENERATOR_1, WM8962_BEEP_ENA,0);
 }
@@ -3525,34 +3530,12 @@ static void wm8962_free_gpio(struct snd_soc_component *component)
 static int wm8962_probe(struct snd_soc_component *component)
 {
 	struct snd_soc_dapm_context *dapm = snd_soc_component_to_dapm(component);
-	int ret;
 	struct wm8962_priv *wm8962 = snd_soc_component_get_drvdata(component);
 	int i;
 	bool dmicclk, dmicdat;
 
 	wm8962->component = component;
 
-	wm8962->disable_nb[0].notifier_call = wm8962_regulator_event_0;
-	wm8962->disable_nb[1].notifier_call = wm8962_regulator_event_1;
-	wm8962->disable_nb[2].notifier_call = wm8962_regulator_event_2;
-	wm8962->disable_nb[3].notifier_call = wm8962_regulator_event_3;
-	wm8962->disable_nb[4].notifier_call = wm8962_regulator_event_4;
-	wm8962->disable_nb[5].notifier_call = wm8962_regulator_event_5;
-	wm8962->disable_nb[6].notifier_call = wm8962_regulator_event_6;
-	wm8962->disable_nb[7].notifier_call = wm8962_regulator_event_7;
-
-	/* This should really be moved into the regulator core */
-	for (i = 0; i < ARRAY_SIZE(wm8962->supplies); i++) {
-		ret = devm_regulator_register_notifier(
-						wm8962->supplies[i].consumer,
-						&wm8962->disable_nb[i]);
-		if (ret != 0) {
-			dev_err(component->dev,
-				"Failed to register regulator notifier: %d\n",
-				ret);
-		}
-	}
-
 	wm8962_add_widgets(component);
 
 	/* Save boards having to disable DMIC when not in use */
@@ -3742,6 +3725,27 @@ static int wm8962_i2c_probe(struct i2c_client *i2c)
 
 	regcache_cache_bypass(wm8962->regmap, false);
 
+	wm8962->disable_nb[0].notifier_call = wm8962_regulator_event_0;
+	wm8962->disable_nb[1].notifier_call = wm8962_regulator_event_1;
+	wm8962->disable_nb[2].notifier_call = wm8962_regulator_event_2;
+	wm8962->disable_nb[3].notifier_call = wm8962_regulator_event_3;
+	wm8962->disable_nb[4].notifier_call = wm8962_regulator_event_4;
+	wm8962->disable_nb[5].notifier_call = wm8962_regulator_event_5;
+	wm8962->disable_nb[6].notifier_call = wm8962_regulator_event_6;
+	wm8962->disable_nb[7].notifier_call = wm8962_regulator_event_7;
+
+	/* This should really be moved into the regulator core */
+	for (i = 0; i < ARRAY_SIZE(wm8962->supplies); i++) {
+		ret = devm_regulator_register_notifier(wm8962->supplies[i].consumer,
+						       &wm8962->disable_nb[i]);
+		if (ret != 0) {
+			dev_err(&i2c->dev,
+				"Failed to register regulator notifier: %d\n",
+				ret);
+			goto err_enable;
+		}
+	}
+
 	ret = wm8962_reset(wm8962);
 	if (ret < 0) {
 		dev_err(&i2c->dev, "Failed to issue reset\n");
-- 
2.50.1