Linux Virtualization - Aug 2018 - [PATCH] drm/cirrus: Use drm_framebuffer_put to avoid kernel oops in clean-up

On Fri, Jul 20, 2018 at 01:27:43PM +0200, Thomas Zimmermann
wrote:
> In the Cirrus driver, the regular clean-up code also performs the clean-up
> of a failed initialization. If the fbdev's framebuffer was not
initialized,
> the clean-up will fail within drm_framebuffer_unregister_private. Booting
> with cirrus.bpp=16 triggers this bug.
> 
> The framebuffer is currently stored directly within struct cirrus_fbdev. To
> fix the bug, we turn it into a pointer that is only set for initialized
> framebuffers. The fbdev's clean-up code skips uninitialized
framebuffers.
> 
> The memory for struct drm_framebuffer is allocated dynamically. This
requires
> additional error handling within cirrusfb_create. The framebuffer clean-up
is
> now performed by drm_framebuffer_put, which also frees the data
strcuture's
> memory.
pushed to drm-misc-next (also the other ones, except the failing ttm_put
patches).

thanks,
  Gerd