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Subject[PATCH v3 1/7] media: imx274: initialize format before v4l2 controls
Date
The current probe function calls v4l2_ctrl_handler_setup() before
initializing the format info. This triggers call paths such as:
imx274_probe -> v4l2_ctrl_handler_setup -> imx274_s_ctrl ->
imx274_set_exposure, where priv->mode_index is accessed before being
assigned.

This is wrong but does not trigger a visible bug because priv is
zero-initialized and 0 is the default value for priv->mode_index. But
this would become a crash in follow-up commits when mode_index is
replaced by a pointer that must always be valid.

Fix the bug before it shows up by initializing struct members early.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>

---
Changed v2 -> v3: nothing

Changed v1 -> v2:
- add "media: " prefix to commit message
---
drivers/media/i2c/imx274.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/media/i2c/imx274.c b/drivers/media/i2c/imx274.c
index 63fb94e7da37..8a8a11b8d75d 100644
--- a/drivers/media/i2c/imx274.c
+++ b/drivers/media/i2c/imx274.c
@@ -1632,6 +1632,16 @@ static int imx274_probe(struct i2c_client *client,

mutex_init(&imx274->lock);

+ /* initialize format */
+ imx274->mode_index = IMX274_MODE_3840X2160;
+ imx274->format.width = imx274_formats[0].size.width;
+ imx274->format.height = imx274_formats[0].size.height;
+ imx274->format.field = V4L2_FIELD_NONE;
+ imx274->format.code = MEDIA_BUS_FMT_SRGGB10_1X10;
+ imx274->format.colorspace = V4L2_COLORSPACE_SRGB;
+ imx274->frame_interval.numerator = 1;
+ imx274->frame_interval.denominator = IMX274_DEF_FRAME_RATE;
+
/* initialize regmap */
imx274->regmap = devm_regmap_init_i2c(client, &imx274_regmap_config);
if (IS_ERR(imx274->regmap)) {
@@ -1720,16 +1730,6 @@ static int imx274_probe(struct i2c_client *client,
goto err_ctrls;
}

- /* initialize format */
- imx274->mode_index = IMX274_MODE_3840X2160;
- imx274->format.width = imx274_formats[0].size.width;
- imx274->format.height = imx274_formats[0].size.height;
- imx274->format.field = V4L2_FIELD_NONE;
- imx274->format.code = MEDIA_BUS_FMT_SRGGB10_1X10;
- imx274->format.colorspace = V4L2_COLORSPACE_SRGB;
- imx274->frame_interval.numerator = 1;
- imx274->frame_interval.denominator = IMX274_DEF_FRAME_RATE;
-
/* load default control values */
ret = imx274_load_default(imx274);
if (ret) {
--
2.7.4
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