This patch add checks for NULL drm_connector_helper_funcs
pointers before derefrencing the variable to avoid NULL pointer
dereference and make the helper function 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 for atomic_check 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_mode_config_func:
* atomic_check = drm_atomic_helper_check
a) drm_atomic_helper_check_modeset
a) handle_conflicting_encoders
c) update_connector_routing
Signed-off-by: Haneen Mohammed <hamohammed...@gmail.com>
---
Changes in v3:
- add checks for drm_connector_helper_funcs only since plane/crtc
helper funcs are necessary for a functional driver
Changes in v2:
- add the least amount of checks to make the helpers optional for vkms
drivers/gpu/drm/drm_atomic_helper.c | 10 +++++-----
drivers/gpu/drm/drm_probe_helper.c | 5 +++--
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c
b/drivers/gpu/drm/drm_atomic_helper.c
index 2a7ceca82b9e..065e7fe1f979 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);
@@ -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;
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);
--
2.17.0
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