2017-11-13 14:17:11

by Daniel Thompson

[permalink] [raw]
Subject: Re: [PATCH 1/3] backlight: as3711_bl: fix device-tree node lookup



On 13/11/17 10:20, Johan Hovold wrote:
> Fix child-node lookup during probe, which ended up searching the whole
> device tree depth-first starting at the parent rather than just matching
> on its children.
>
> To make things worse, the parent mfd node was also prematurely freed.
>
> Note that the nodes returned from the two calls to of_parse_phandle()
> are also leaking, but fixing that is a bit more involved as pointers to
> node fields are being stored for later use.

Is using a devm_kstrdup() to remember the full_name sufficient so get
each of the FIXMEs cleaned up as well?


Daniel.


> Fixes: 59eb2b5e57ea ("drivers/video/backlight/as3711_bl.c: add OF support")
> Cc: stable <[email protected]> # 3.10
> Cc: Guennadi Liakhovetski <[email protected]>
> Signed-off-by: Johan Hovold <[email protected]>
> ---
> drivers/video/backlight/as3711_bl.c | 35 +++++++++++++++++++++++++----------
> 1 file changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/video/backlight/as3711_bl.c b/drivers/video/backlight/as3711_bl.c
> index 734a9158946b..21ce56053c88 100644
> --- a/drivers/video/backlight/as3711_bl.c
> +++ b/drivers/video/backlight/as3711_bl.c
> @@ -262,15 +262,16 @@ static int as3711_bl_register(struct platform_device *pdev,
> static int as3711_backlight_parse_dt(struct device *dev)
> {
> struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
> - struct device_node *bl =
> - of_find_node_by_name(dev->parent->of_node, "backlight"), *fb;
> + struct device_node *bl, *fb;
> int ret;
>
> + bl = of_get_child_by_name(dev->parent->of_node, "backlight");
> if (!bl) {
> dev_dbg(dev, "backlight node not found\n");
> return -ENODEV;
> }
>
> + /* FIXME: need to drop reference to returned node */
> fb = of_parse_phandle(bl, "su1-dev", 0);
> if (fb) {
> pdata->su1_fb = fb->full_name;
> @@ -279,9 +280,10 @@ static int as3711_backlight_parse_dt(struct device *dev)
> if (pdata->su1_max_uA <= 0)
> ret = -EINVAL;
> if (ret < 0)
> - return ret;
> + goto err_put_bl;
> }
>
> + /* FIXME: need to drop reference to returned node */
> fb = of_parse_phandle(bl, "su2-dev", 0);
> if (fb) {
> int count = 0;
> @@ -292,7 +294,7 @@ static int as3711_backlight_parse_dt(struct device *dev)
> if (pdata->su2_max_uA <= 0)
> ret = -EINVAL;
> if (ret < 0)
> - return ret;
> + goto err_put_bl;
>
> if (of_find_property(bl, "su2-feedback-voltage", NULL)) {
> pdata->su2_feedback = AS3711_SU2_VOLTAGE;
> @@ -314,8 +316,10 @@ static int as3711_backlight_parse_dt(struct device *dev)
> pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
> count++;
> }
> - if (count != 1)
> - return -EINVAL;
> + if (count != 1) {
> + ret = -EINVAL;
> + goto err_put_bl;
> + }
>
> count = 0;
> if (of_find_property(bl, "su2-fbprot-lx-sd4", NULL)) {
> @@ -334,8 +338,10 @@ static int as3711_backlight_parse_dt(struct device *dev)
> pdata->su2_fbprot = AS3711_SU2_GPIO4;
> count++;
> }
> - if (count != 1)
> - return -EINVAL;
> + if (count != 1) {
> + ret = -EINVAL;
> + goto err_put_bl;
> + }
>
> count = 0;
> if (of_find_property(bl, "su2-auto-curr1", NULL)) {
> @@ -355,11 +361,20 @@ static int as3711_backlight_parse_dt(struct device *dev)
> * At least one su2-auto-curr* must be specified iff
> * AS3711_SU2_CURR_AUTO is used
> */
> - if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO))
> - return -EINVAL;
> + if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO)) {
> + ret = -EINVAL;
> + goto err_put_bl;
> + }
> }
>
> + of_node_put(bl);
> +
> return 0;
> +
> +err_put_bl:
> + of_node_put(bl);
> +
> + return ret;
> }
>
> static int as3711_backlight_probe(struct platform_device *pdev)
>

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