This patch add checks for NULL drm_[connector/crtc/plane]_helper_funcs pointers before derefrencing the variable to avoid NULL pointer dereference and make the helper functions optional in the following cases:
1) when using drm_helper_probe_single_connector_modes for fill_modes callback in the drm_connector_funcs. 2) using drm_atomic_helper_[check/commit] for atomic_[check/commit] callbacks in the drm_mode_config_funcs.
The dependency is as follow:
drm_connector_funcs: * fill_modes = drm_helper_probe_single_connector_modes b) drm_helper_probe_detect -> drm_connector_helper_funcs
drm_mode_config_funcs: * atomic_check = drm_atomic_helper_check a) drm_atomic_helper_check_modeset -> drm_connector helper_funcs a) handle_conflicting_encoders -> drm_connector_helper_funcs b) mode_fixup -> drm_crtc_helper_funcs c) update_connector_routing -> drm_connectot_helper_funcs
* atomic_commit = drm_atomic_helper_commit a) drm_atomic_helper_prepare_planes -> drm_plane_helper_funcs b) drm_atomic_helper_cleanup_planes -> drm_plane_helper_funcs
Signed-off-by: Haneen Mohammed hamohammed.sa@gmail.com --- Chanes in v2: - add the least amount of checks to make the helpers optional for vkms
drivers/gpu/drm/drm_atomic_helper.c | 16 ++++++++-------- drivers/gpu/drm/drm_probe_helper.c | 5 +++-- 2 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 2a7ceca82b9e..ff3684c4a83c 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -112,9 +112,9 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state, if (!new_conn_state->crtc) continue;
- if (funcs->atomic_best_encoder) + if (funcs && funcs->atomic_best_encoder) new_encoder = funcs->atomic_best_encoder(connector, new_conn_state); - else if (funcs->best_encoder) + else if (funcs && funcs->best_encoder) new_encoder = funcs->best_encoder(connector); else new_encoder = drm_atomic_helper_best_encoder(connector); @@ -308,10 +308,10 @@ update_connector_routing(struct drm_atomic_state *state,
funcs = connector->helper_private;
- if (funcs->atomic_best_encoder) + if (funcs && funcs->atomic_best_encoder) new_encoder = funcs->atomic_best_encoder(connector, new_connector_state); - else if (funcs->best_encoder) + else if (funcs && funcs->best_encoder) new_encoder = funcs->best_encoder(connector); else new_encoder = drm_atomic_helper_best_encoder(connector); @@ -438,7 +438,7 @@ mode_fixup(struct drm_atomic_state *state) continue;
funcs = crtc->helper_private; - if (!funcs->mode_fixup) + if (!funcs || !funcs->mode_fixup) continue;
ret = funcs->mode_fixup(crtc, &new_crtc_state->mode, @@ -639,7 +639,7 @@ drm_atomic_helper_check_modeset(struct drm_device *dev, new_crtc_state->connectors_changed = true; }
- if (funcs->atomic_check) + if (funcs && funcs->atomic_check) ret = funcs->atomic_check(connector, new_connector_state); if (ret) return ret; @@ -2117,7 +2117,7 @@ int drm_atomic_helper_prepare_planes(struct drm_device *dev,
funcs = plane->helper_private;
- if (funcs->prepare_fb) { + if (funcs && funcs->prepare_fb) { ret = funcs->prepare_fb(plane, new_plane_state); if (ret) goto fail; @@ -2412,7 +2412,7 @@ void drm_atomic_helper_cleanup_planes(struct drm_device *dev,
funcs = plane->helper_private;
- if (funcs->cleanup_fb) + if (funcs && funcs->cleanup_fb) funcs->cleanup_fb(plane, plane_state); } } diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index 527743394150..2fea54d16ebb 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -320,7 +320,7 @@ drm_helper_probe_detect(struct drm_connector *connector, if (ret) return ret;
- if (funcs->detect_ctx) + if (funcs && funcs->detect_ctx) return funcs->detect_ctx(connector, ctx, force); else if (connector->funcs->detect) return connector->funcs->detect(connector, force); @@ -480,7 +480,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector, goto prune; }
- count = (*connector_funcs->get_modes)(connector); + if (connector_funcs && connector_funcs->get_modes) + count = (*connector_funcs->get_modes)(connector);
if (count == 0 && connector->status == connector_status_connected) count = drm_add_modes_noedid(connector, 1024, 768);