# Re: \[PATCH\] drivers: video: backlight: Fix NULL Pointer Dereference in backlight\_device\_register()

- From: Daniel Thompson \<danielt@kernel.org\>
- Date: 2025-02-13 21:07:37 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2025/02/2926180
- Thread: https://ratatoskr.run/dri-devel/2025/01/2906741/t.md

```text
On Mon, Feb 03, 2025 at 03:21:23PM +0200, Jani Nikula wrote:
> On Thu, 30 Jan 2025, Haoyu Li [ref] wrote:
> > In the function "wled_probe", the "wled->name" is dynamically allocated
> > (wled_probe -> wled_configure -> devm_kasprintf), which is possible
> > to be null.
> >
> > In the call trace: wled_probe -> devm_backlight_device_register
> > -> backlight_device_register, this "name" variable is directly
> > dereferenced without checking. We add a null-check statement.
> >
> > Fixes: f86b77583d88 ("backlight: pm8941: Convert to using %pOFn instead of device_node.name")
> > Signed-off-by: Haoyu Li <redacted>
> > Cc: <redacted>
>
> IMO whoever allocates should be responsible for checking NULL instead of
> passing NULL around and expecting everyone check their input for NULL.

Agreed. This should be fixed in at callsites.


Daniel.
```