[PATCH 5.10.y] drm/cirrus: fix a NULL vs IS_ERR() checks

[Greg Kroah-Hartman]

On Sun, Apr 24, 2022 at 11:27:17AM +0800, Shile Zhang wrote:
> Hi David and Daniel,
> 
> Sorry but could you please help to check this issue?
> Due to the function 'drm_gem_shmem_vmap' could return ERROR pointers which
> will cause the kernel crash due to 'cirrus_fb_blit_rect' only check the
> pointer.
> 
> Since the related code has been refactoring in mainline, so this issue only
> happened in stable 5.10.y branch.
> 
> @Greg
> I think it is probably not realistic to backport the related refactoring
> from mainline directly, so I just give this bugfix patch only for 5.10.y
> branch.

I'm sorry, but I do not have "this bugfix" in my queue anymore,
considering it is so old.  Please rebase and resubmit.

thanks,

greg k-h