[PATCH v3] ALSA: hda: cs35l41: Fix ACPI device reference leak on probe failure

[Ma Ke]

cs35l41_hda_probe() takes an acpi_device through
cs35l41_hda_read_acpi() and stores it in cs35l41->dacpi. Only the
failures that happen later reach the err: label, which is where that
reference and cs35l41->acpi_subsystem_id are released, so the early
return taken when cs35l41_hda_read_acpi() fails leaves both behind.

Keep the ownership in the caller instead of dropping the reference
inside cs35l41_hda_read_acpi(). That removes the need to work out
whether a given failure path has already released it, and with it the
double put that cs35l41_hda_parse_acpi() would otherwise cause when it
fails after having released the device itself.

cs35l41_hda_parse_acpi() and the !physdev path no longer put the
reference, and the early failure enters the existing err: cleanup tail
through a new err_acpi label.

The label sits between the reset of the codec and the gpio cleanup, so
an early failure also releases the reset and chip-select descriptors
that cs35l41_hda_parse_acpi() may already have taken, while still
skipping cs35l41_safe_reset() on a codec that was never brought up.

cs35l41->dacpi comes from devm_kzalloc() and is only assigned once the
ACPI device has been found, so the put is a no-op when the lookup
itself failed.

Found by code review.

Fixes: 447106e92a0c ("ALSA: hda: cs35l41: Support mute notifications for CS35L41 HDA")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ma Ke <make_ruc2021@xxxxxxx>
---
Changes in v3:
- Modify the patch. Thanks for Takashi Iwai and Sashiko's suggestions.
Changes in v2:
- cs35l41_hda_parse_acpi() drops cs35l41->dacpi in its own err: label, so
  the err_acpi path added by v1 would have dropped that reference a second
  time. Clear cs35l41->dacpi there as well, not only on the !physdev path.
---
 sound/hda/codecs/side-codecs/cs35l41_hda.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/sound/hda/codecs/side-codecs/cs35l41_hda.c b/sound/hda/codecs/side-codecs/cs35l41_hda.c
index 62296be45c55..d50c3d8f5303 100644
--- a/sound/hda/codecs/side-codecs/cs35l41_hda.c
+++ b/sound/hda/codecs/side-codecs/cs35l41_hda.c
@@ -1907,7 +1907,6 @@ int cs35l41_hda_parse_acpi(struct cs35l41_hda *cs35l41, struct device *physdev,
 	hw_cfg->valid = false;
 	hw_cfg->gpio1.valid = false;
 	hw_cfg->gpio2.valid = false;
-	acpi_dev_put(cs35l41->dacpi);
 
 	return ret;
 }
@@ -1928,10 +1927,8 @@ static int cs35l41_hda_read_acpi(struct cs35l41_hda *cs35l41, const char *hid, i
 	cs35l41->dacpi = adev;
 	struct device *physdev __free(put_device) =
 		get_device(acpi_get_first_physical_node(adev));
-	if (!physdev) {
-		acpi_dev_put(adev);
+	if (!physdev)
 		return -ENODEV;
-	}
 
 	sub = acpi_get_subsystem_id(ACPI_HANDLE(physdev));
 	if (IS_ERR(sub))
@@ -1986,8 +1983,10 @@ int cs35l41_hda_probe(struct device *dev, const char *device_name, int id, int i
 	dev_set_drvdata(dev, cs35l41);
 
 	ret = cs35l41_hda_read_acpi(cs35l41, device_name, id);
-	if (ret)
-		return dev_err_probe(cs35l41->dev, ret, "Platform not supported\n");
+	if (ret) {
+		dev_err_probe(cs35l41->dev, ret, "Platform not supported\n");
+		goto err_acpi;
+	}
 
 	if (IS_ERR(cs35l41->reset_gpio)) {
 		ret = PTR_ERR(cs35l41->reset_gpio);
@@ -2074,6 +2073,7 @@ int cs35l41_hda_probe(struct device *dev, const char *device_name, int id, int i
 err:
 	if (cs35l41_safe_reset(cs35l41->regmap, cs35l41->hw_cfg.bst_type))
 		gpiod_set_value_cansleep(cs35l41->reset_gpio, 0);
+err_acpi:
 	gpiod_put(cs35l41->reset_gpio);
 	gpiod_put(cs35l41->cs_gpio);
 	acpi_dev_put(cs35l41->dacpi);
-- 
2.43.0