Re: [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