linux/drivers/gpu
Stefan Christ 1b99b72489 drm/fb-helper: fix segfaults in drm_fb_helper_debug_*
A drm driver that is implementing

      fb_debug_enter and fb_debug_leave

in struct fb_ops with drm fb helper functions

     drm_fb_helper_debug_enter and drm_fb_helper_debug_leave

must also implement the callback 'mode_set_base_atomic' in struct
drm_crtc_helper_funcs. See Documentation/DocBook/kgdb.tmpl.  The current
implementation will segfault when 'mode_set_base_atomic' is a NULL
pointer.

Before this patch at least the drm drivers armada, ast, qxl, udl and
virtio do not have a 'mode_set_base_atomic' implementation but using
drm_fb_helper_debug_(enter|leave). So these drivers may segfault when
callbacks fb_debug_(enter|leave) are called.

Avoid the issue by just checking for NULL pointers. So all drivers can
unconditionally implement fb_debug_(enter|leave) with the drm_fb_helper
functions. If callback 'mode_set_base_atomic' is not implemented, the
code in drm_fb_helper_debug_(enter|leave) does effectively nothing.

Signed-off-by: Stefan Christ <contact@stefanchrist.eu>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1479078208-25221-2-git-send-email-contact@stefanchrist.eu
2016-11-14 07:47:34 +01:00
..
drm drm/fb-helper: fix segfaults in drm_fb_helper_debug_* 2016-11-14 07:47:34 +01:00
host1x drm/tegra: dsi: Enhance runtime power management 2016-08-24 15:58:57 +02:00
ipu-v3 imx-drm plane update cleanup, YUV formats 2016-11-11 09:31:27 +10:00
vga drivers/gpu/vga: allocate vga_arb_write() buffer on stack 2016-10-17 08:21:14 +02:00
Makefile