diff mbox series

[v5,14/19] drm/hdmi: Rename __drm_atomic_helper_connector_hdmi_reset()

Message ID 20260519-drm-mode-config-init-v5-14-388b03321e38@kernel.org (mailing list archive)
State New
Headers
Series drm/atomic: Rework initial state allocation |

Commit Message

Maxime Ripard May 19, 2026, 9:01 a.m. UTC 
__drm_atomic_helper_connector_hdmi_reset() is typically used to
initialize a newly allocated drm_connector_state when the connector is
using the HDMI helpers, and is being called by the
drm_connector_funcs.reset implementation.

Since we want to consolidate DRM objects state allocation around the
atomic_create_state callback that will only allocate and initialize a
new drm_connector_state instance, we will need to call
__drm_atomic_helper_connector_hdmi_reset() from both the reset and
atomic_create hooks.

To avoid any confusion, we can thus rename
__drm_atomic_helper_connector_hdmi_reset() to
__drm_atomic_helper_connector_hdmi_state_init().

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
 drivers/gpu/drm/display/drm_bridge_connector.c     |  4 ++--
 drivers/gpu/drm/display/drm_hdmi_state_helper.c    | 15 ++++++++-------
 drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c             |  2 +-
 drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c |  2 +-
 drivers/gpu/drm/vc4/vc4_hdmi.c                     |  2 +-
 include/drm/display/drm_hdmi_state_helper.h        |  4 ++--
 6 files changed, 15 insertions(+), 14 deletions(-)

Comments

sashiko-bot@kernel.org May 19, 2026, 9:13 a.m. UTC | #1 
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] __drm_atomic_helper_connector_hdmi_state_init() dereferences new_conn_state without a NULL check, leading to a kernel panic if state allocation fails in drm_atomic_helper_connector_reset(). This problem wasn't introduced by this patch, but existed in the previous implementation.
--

commit ca36932b2899a887d5e634584333e43a5290dc5b
Author: Maxime Ripard <mripard@kernel.org>

drm/hdmi: Rename __drm_atomic_helper_connector_hdmi_reset()

This commit renames __drm_atomic_helper_connector_hdmi_reset() to
__drm_atomic_helper_connector_hdmi_state_init(). This prepares for
consolidating DRM objects state allocation around the atomic_create_state
callback.

> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index a161d3b00a255..74dce4be0c008 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -508,7 +508,7 @@ static int vc4_hdmi_connector_atomic_check(struct drm_connector *connector,
>  static void vc4_hdmi_connector_reset(struct drm_connector *connector)
>  {
>  	drm_atomic_helper_connector_reset(connector);
> -	__drm_atomic_helper_connector_hdmi_reset(connector, connector->state);
> +	__drm_atomic_helper_connector_hdmi_state_init(connector, connector->state);

Can this result in a NULL pointer dereference if memory allocation fails?

This problem appears to have existed prior to this patch, but remains present.

If kzalloc_obj() fails inside drm_atomic_helper_connector_reset(), it will
set connector->state to NULL. This NULL pointer is then passed into
__drm_atomic_helper_connector_hdmi_state_init():

void __drm_atomic_helper_connector_hdmi_state_init(...,
						   struct drm_connector_state *new_conn_state)
{
	...
	new_conn_state->max_bpc = max_bpc;
	...
}

Does this code need a check for new_conn_state before dereferencing it,
or should the caller check if connector->state is valid before calling this
initialization function?
diff mbox series

Patch

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 649969fca141..50408af746d8 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -270,12 +270,12 @@  static void drm_bridge_connector_reset(struct drm_connector *connector)
 	struct drm_bridge_connector *bridge_connector =
 		to_drm_bridge_connector(connector);
 
 	drm_atomic_helper_connector_reset(connector);
 	if (bridge_connector->bridge_hdmi)
-		__drm_atomic_helper_connector_hdmi_reset(connector,
-							 connector->state);
+		__drm_atomic_helper_connector_hdmi_state_init(connector,
+							      connector->state);
 }
 
 static const struct drm_connector_funcs drm_bridge_connector_funcs = {
 	.reset = drm_bridge_connector_reset,
 	.detect = drm_bridge_connector_detect,
diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
index 4867edbf2622..a331ebdd65af 100644
--- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
+++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
@@ -304,29 +304,30 @@ 
  *		--kunitconfig=drivers/gpu/drm/tests \
  *		drm_atomic_helper_connector_hdmi_*
  */
 
 /**
- * __drm_atomic_helper_connector_hdmi_reset() - Initializes all HDMI @drm_connector_state resources
+ * __drm_atomic_helper_connector_hdmi_state_init() - Initialize all HDMI @drm_connector_state resources
  * @connector: DRM connector
- * @new_conn_state: connector state to reset
+ * @new_conn_state: connector state to initialize
  *
  * Initializes all HDMI resources from a @drm_connector_state without
  * actually allocating it. This is useful for HDMI drivers, in
- * combination with __drm_atomic_helper_connector_reset() or
- * drm_atomic_helper_connector_reset().
+ * combination with __drm_atomic_helper_connector_state_init(),
+ * drm_atomic_helper_connector_reset(), or
+ * drm_atomic_helper_connector_create_state().
  */
-void __drm_atomic_helper_connector_hdmi_reset(struct drm_connector *connector,
-					      struct drm_connector_state *new_conn_state)
+void __drm_atomic_helper_connector_hdmi_state_init(struct drm_connector *connector,
+						   struct drm_connector_state *new_conn_state)
 {
 	unsigned int max_bpc = connector->max_bpc;
 
 	new_conn_state->max_bpc = max_bpc;
 	new_conn_state->max_requested_bpc = max_bpc;
 	new_conn_state->hdmi.broadcast_rgb = DRM_HDMI_BROADCAST_RGB_AUTO;
 }
-EXPORT_SYMBOL(__drm_atomic_helper_connector_hdmi_reset);
+EXPORT_SYMBOL(__drm_atomic_helper_connector_hdmi_state_init);
 
 static enum hdmi_colorspace
 output_color_format_to_hdmi_colorspace(const struct drm_connector *connector,
 				       enum drm_output_color_format fmt)
 {
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
index 07e2afcb4f95..3cad8f9bc529 100644
--- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
@@ -283,11 +283,11 @@  sun4i_hdmi_connector_detect(struct drm_connector *connector, bool force)
 }
 
 static void sun4i_hdmi_connector_reset(struct drm_connector *connector)
 {
 	drm_atomic_helper_connector_reset(connector);
-	__drm_atomic_helper_connector_hdmi_reset(connector, connector->state);
+	__drm_atomic_helper_connector_hdmi_state_init(connector, connector->state);
 }
 
 static const struct drm_connector_funcs sun4i_hdmi_connector_funcs = {
 	.detect			= sun4i_hdmi_connector_detect,
 	.fill_modes		= drm_helper_probe_single_connector_modes,
diff --git a/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c b/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
index c9819c3fc635..e89e1af7a811 100644
--- a/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c
@@ -166,11 +166,11 @@  static const struct drm_connector_helper_funcs dummy_connector_helper_funcs = {
 };
 
 static void dummy_hdmi_connector_reset(struct drm_connector *connector)
 {
 	drm_atomic_helper_connector_reset(connector);
-	__drm_atomic_helper_connector_hdmi_reset(connector, connector->state);
+	__drm_atomic_helper_connector_hdmi_state_init(connector, connector->state);
 }
 
 static const struct drm_connector_funcs dummy_connector_funcs = {
 	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
 	.atomic_duplicate_state	= drm_atomic_helper_connector_duplicate_state,
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index a161d3b00a25..74dce4be0c00 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -506,11 +506,11 @@  static int vc4_hdmi_connector_atomic_check(struct drm_connector *connector,
 }
 
 static void vc4_hdmi_connector_reset(struct drm_connector *connector)
 {
 	drm_atomic_helper_connector_reset(connector);
-	__drm_atomic_helper_connector_hdmi_reset(connector, connector->state);
+	__drm_atomic_helper_connector_hdmi_state_init(connector, connector->state);
 	drm_atomic_helper_connector_tv_margins_reset(connector);
 }
 
 static const struct drm_connector_funcs vc4_hdmi_connector_funcs = {
 	.force = drm_atomic_helper_connector_hdmi_force,
diff --git a/include/drm/display/drm_hdmi_state_helper.h b/include/drm/display/drm_hdmi_state_helper.h
index 0adc30c55ec9..13375bd0f4ae 100644
--- a/include/drm/display/drm_hdmi_state_helper.h
+++ b/include/drm/display/drm_hdmi_state_helper.h
@@ -9,12 +9,12 @@  struct drm_connector_state;
 struct drm_display_mode;
 struct hdmi_audio_infoframe;
 
 enum drm_connector_status;
 
-void __drm_atomic_helper_connector_hdmi_reset(struct drm_connector *connector,
-					      struct drm_connector_state *new_conn_state);
+void __drm_atomic_helper_connector_hdmi_state_init(struct drm_connector *connector,
+						   struct drm_connector_state *new_conn_state);
 
 int drm_atomic_helper_connector_hdmi_check(struct drm_connector *connector,
 					   struct drm_atomic_commit *state);
 
 int drm_atomic_helper_connector_hdmi_update_audio_infoframe(struct drm_connector *connector,