[PATCH v4 1/8] media: imx274: initialize format before v4l2 controls

[Luca Ceresoli]

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 <l...@lucaceresoli.net>
Cc: Sakari Ailus <sakari.ai...@linux.intel.com>

---
Changed v3 -> v4: nothing

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