A divide error bug in framebuffer_check

[Ville Syrjälä]

On Tue, Sep 13, 2022 at 01:49:40AM +0800, butt3rflyh4ck wrote:
> Hi, there is a divide error bug in framebuffer_check in
> drivers/gpu/drm/drm_framebuffer.c in the latest kernel.
> we can trigger it via drm_mode_addfb2 IOCTL.
> The call trace is drm_mode_addfb2 -> drm_internal_framebuffer_create
> ->  framebuffer_check.
> let us see code below:
> ```
<snip>
> { .format = DRM_FORMAT_Q410, .depth = 0,
>   .num_planes = 3, .char_per_block = { 2, 2, 2 },
>   .block_w = { 1, 1, 1 }, .block_h = { 1, 1, 1 }, .hsub = 0,
>   .vsub = 0, .is_yuv = true },
> { .format = DRM_FORMAT_Q401, .depth = 0,
>   .num_planes = 3, .char_per_block = { 2, 2, 2 },
>   .block_w = { 1, 1, 1 }, .block_h = { 1, 1, 1 }, .hsub = 0,
>   .vsub = 0, .is_yuv = true },
> ```
> we can see format.hsub and format.vsub all are NULL.

Yeah, those look borked.

Added in commit 94b292b27734 ("drm: drm_fourcc: add NV15, Q410, Q401 YUV formats")

Adding the relevant people to cc...

-- 
Ville Syrjälä
Intel