diff options
| author | Stefan Christ <contact@stefanchrist.eu> | 2016-11-14 02:03:11 +0300 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-11-14 09:47:34 +0300 |
| commit | 1b99b72489c6a2d9fb3156b403510dc5f6c8b6a5 (patch) | |
| tree | e8783eb730079ffc9673767c562db9316d5c383b /drivers | |
| parent | 554dd692afd5d449168b5007841742db4a2ed17b (diff) | |
| download | linux-1b99b72489c6a2d9fb3156b403510dc5f6c8b6a5.tar.xz | |
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
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/drm_fb_helper.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 36797c465edc..14547817566d 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -256,6 +256,9 @@ int drm_fb_helper_debug_enter(struct fb_info *info) continue; funcs = mode_set->crtc->helper_private; + if (funcs->mode_set_base_atomic == NULL) + continue; + drm_fb_helper_save_lut_atomic(mode_set->crtc, helper); funcs->mode_set_base_atomic(mode_set->crtc, mode_set->fb, @@ -309,6 +312,9 @@ int drm_fb_helper_debug_leave(struct fb_info *info) continue; } + if (funcs->mode_set_base_atomic == NULL) + continue; + drm_fb_helper_restore_lut_atomic(mode_set->crtc); funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x, crtc->y, LEAVE_ATOMIC_MODE_SET); |