linux-kernel - [PATCH AUTOSEL 4.19 01/53] ASoC: tlv320aic3x: fix reset gpio reference counting

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Message-Id: <20190427014051.7522-1-sashal@kernel.org>
Date:   Fri, 26 Apr 2019 21:39:58 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Philipp Puschmann <philipp.puschmann@...ix.com>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.19 01/53] ASoC: tlv320aic3x: fix reset gpio reference counting

From: Philipp Puschmann <philipp.puschmann@...ix.com>

[ Upstream commit 82ad759143ed77673db0d93d53c1cde7b99917ee ]

This patch fixes a bug that prevents freeing the reset gpio on unloading
the module.

aic3x_i2c_probe is called when loading the module and it calls list_add
with a probably uninitialized list entry aic3x->list (next = prev = NULL)).
So even if list_del is called it does nothing and in the end the gpio_reset
is not freed. Then a repeated module probing fails silently because
gpio_request fails.

When moving INIT_LIST_HEAD to aic3x_i2c_probe we also have to move
list_del to aic3x_i2c_remove because aic3x_remove may be called
multiple times without aic3x_i2c_remove being called which leads to
a NULL pointer dereference.

Signed-off-by: Philipp Puschmann <philipp.puschmann@...ix.com>
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 sound/soc/codecs/tlv320aic3x.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/tlv320aic3x.c b/sound/soc/codecs/tlv320aic3x.c
index 6a271e6e6b8f..6c0a3dad44b8 100644
--- a/sound/soc/codecs/tlv320aic3x.c
+++ b/sound/soc/codecs/tlv320aic3x.c
@@ -1599,7 +1599,6 @@ static int aic3x_probe(struct snd_soc_component *component)
 	struct aic3x_priv *aic3x = snd_soc_component_get_drvdata(component);
 	int ret, i;
 
-	INIT_LIST_HEAD(&aic3x->list);
 	aic3x->component = component;
 
 	for (i = 0; i < ARRAY_SIZE(aic3x->supplies); i++) {
@@ -1682,7 +1681,6 @@ static void aic3x_remove(struct snd_soc_component *component)
 	struct aic3x_priv *aic3x = snd_soc_component_get_drvdata(component);
 	int i;
 
-	list_del(&aic3x->list);
 	for (i = 0; i < ARRAY_SIZE(aic3x->supplies); i++)
 		regulator_unregister_notifier(aic3x->supplies[i].consumer,
 					      &aic3x->disable_nb[i].nb);
@@ -1880,6 +1878,7 @@ static int aic3x_i2c_probe(struct i2c_client *i2c,
 	if (ret != 0)
 		goto err_gpio;
 
+	INIT_LIST_HEAD(&aic3x->list);
 	list_add(&aic3x->list, &reset_list);
 
 	return 0;
@@ -1896,6 +1895,8 @@ static int aic3x_i2c_remove(struct i2c_client *client)
 {
 	struct aic3x_priv *aic3x = i2c_get_clientdata(client);
 
+	list_del(&aic3x->list);
+
 	if (gpio_is_valid(aic3x->gpio_reset) &&
 	    !aic3x_is_shared_reset(aic3x)) {
 		gpio_set_value(aic3x->gpio_reset, 0);
-- 
2.19.1