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

Sasha Levin
2019-04-27T01:40:59Z

From: Philipp Puschmann <philipp.puschmann@emlix.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@emlix.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.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