[PATCH] dispnv50: atom: fix an incorrect NULL check on list iterator

[Emil Velikov]

On Sun, 27 Mar 2022 at 08:39, Xiaomeng Tong <xiam0nd.tong at gmail.com> wrote:
>
> The bug is here:
>         return encoder;
>
> The list iterator value 'encoder' will *always* be set and non-NULL
> by drm_for_each_encoder_mask(), so it is incorrect to assume that the
> iterator value will be NULL if the list is empty or no element found.
> Otherwise it will bypass some NULL checks and lead to invalid memory
> access passing the check.
>
> To fix this bug, just return 'encoder' when found, otherwise return
> NULL.
>

Isn't this covered by the upcoming list* iterator rework [1] or is
this another iterator glitch?
IMHO we should be looking at fixing the implementation and not the
hundreds of users through the kernel.

HTH
-Emil
[1] https://lwn.net/Articles/887097/