drm/i915/fbdev: Check for the framebuffer before use
authorChris Wilson <chris@chris-wilson.co.uk>
Wed, 13 Jul 2016 17:34:45 +0000 (18:34 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Thu, 14 Jul 2016 20:32:27 +0000 (21:32 +0100)
commit6bc265424df02f8162f4a17a37e4982e1c64460e
treeca46f09572b65fcdaf305a0d7022757d7bab0d66
parent0b8c0e9c3354953a5d6f90ece82961017053dc74
drm/i915/fbdev: Check for the framebuffer before use

If the fbdev probing fails, and in our error path we fail to clear the
dev_priv->fbdev, then we can try and use a dangling fbdev pointer, and
in particular a NULL fb. This could also happen in pathological cases
where we try to operate on the fbdev prior to it being probed.

Reported-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1468431285-28264-2-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
drivers/gpu/drm/i915/intel_fbdev.c