[PATCH v2] ASoC: wcd934x: fix error handling in wcd934x_codec_parse_data()

[Ma Ke]

wcd934x_codec_parse_data() contains a device reference count leak in
of_slim_get_device() where device_find_child() increases the reference
count of the device but this reference is not properly decreased in
the success path. Add put_device() in wcd934x_codec_parse_data() and
add devm_add_action_or_reset() in the probe function, which ensures
that the reference count of the device is correctly managed.

Memory leak in regmap_init_slimbus() as the allocated regmap is not
released when the device is removed. Using devm_regmap_init_slimbus()
instead of regmap_init_slimbus() to ensure automatic regmap cleanup on
device removal.

Calling path: of_slim_get_device() -> of_find_slim_device() ->
device_find_child(). As comment of device_find_child() says, 'NOTE:
you will need to drop the reference with put_device() after use.'.

Found by code review.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: a61f3b4f476e ("ASoC: wcd934x: add support to wcd9340/wcd9341 codec")
Signed-off-by: Ma Ke <make24@xxxxxxxxxxx>
---
Changes in v2:
- modified the handling in the success path and fixed the memory leak for regmap as suggestions.
---
 sound/soc/codecs/wcd934x.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/wcd934x.c b/sound/soc/codecs/wcd934x.c
index 1bb7e1dc7e6b..b472320d1ca4 100644
--- a/sound/soc/codecs/wcd934x.c
+++ b/sound/soc/codecs/wcd934x.c
@@ -5847,11 +5847,13 @@ static int wcd934x_codec_parse_data(struct wcd934x_codec *wcd)
 		return dev_err_probe(dev, -EINVAL, "Unable to get SLIM Interface device\n");
 
 	slim_get_logical_addr(wcd->sidev);
-	wcd->if_regmap = regmap_init_slimbus(wcd->sidev,
+	wcd->if_regmap = devm_regmap_init_slimbus(wcd->sidev,
 				  &wcd934x_ifc_regmap_config);
-	if (IS_ERR(wcd->if_regmap))
+	if (IS_ERR(wcd->if_regmap)) {
+		put_device(&wcd->sidev->dev);
 		return dev_err_probe(dev, PTR_ERR(wcd->if_regmap),
 				     "Failed to allocate ifc register map\n");
+	}

 	of_property_read_u32(dev->parent->of_node, "qcom,dmic-sample-rate",
 			     &wcd->dmic_sample_rate);
@@ -5893,6 +5895,10 @@ static int wcd934x_codec_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;

+	ret = devm_add_action_or_reset(dev, (void (*)(void *))put_device, &wcd->sidev->dev);
+	if (ret)
+		return ret;
+
 	/* set default rate 9P6MHz */
 	regmap_update_bits(wcd->regmap, WCD934X_CODEC_RPM_CLK_MCLK_CFG,
 			   WCD934X_CODEC_RPM_CLK_MCLK_CFG_MCLK_MASK,
-- 
2.17.1