27 Mar
2022
27 Mar
'22
3:59 p.m.
On Sun, 27 Mar 2022 at 08:39, Xiaomeng Tong xiam0nd.tong@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/