drm_atomic_get_new_connector_for_encoder and
drm_atomic_get_new_connector_state could return Null.
Thus, add the null pointer check for them with a similar format with
it6505_bridge_atomic_enable in ITE IT6505.

Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
Fixes: 049723628716 ("drm/bridge: Add ITE IT6263 LVDS to HDMI converter")
---
 drivers/gpu/drm/bridge/ite-it6263.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6263.c b/drivers/gpu/drm/bridge/ite-it6263.c
index a3a63a977b0a..3a20b2088bf9 100644
--- a/drivers/gpu/drm/bridge/ite-it6263.c
+++ b/drivers/gpu/drm/bridge/ite-it6263.c
@@ -590,15 +590,28 @@ static void it6263_bridge_atomic_enable(struct drm_bridge *bridge,
 	struct drm_connector *connector;
 	bool is_stable = false;
 	struct drm_crtc *crtc;
+	struct drm_connector_state *conn_state;
 	unsigned int val;
 	bool pclk_high;
 	int i, ret;
 
 	connector = drm_atomic_get_new_connector_for_encoder(state,
 							     bridge->encoder);
-	crtc = drm_atomic_get_new_connector_state(state, connector)->crtc;
+	if (WARN_ON(!connector))
+		return;
+
+	conn_state = drm_atomic_get_new_connector_state(state, connector);
+	if (WARN_ON(!conn_state))
+		return;
+
+	crtc = conn_state->crtc;
 	crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+	if (WARN_ON(!crtc_state))
+		return;
+
 	mode = &crtc_state->adjusted_mode;
+	if (WARN_ON(!mode))
+		return;
 
 	regmap_write(regmap, HDMI_REG_HDMI_MODE, TX_HDMI_MODE);
 
-- 
2.34.1

On Tue, Jul 22, 2025 at 03:41:14PM -0500, Chenyuan Yang wrote:
> drm_atomic_get_new_connector_for_encoder and
> drm_atomic_get_new_connector_state could return Null.

They can, but not in that scenario. atomic_enable will never be called
if either would return NULL.

In which situation did you trigger this bug?

> Thus, add the null pointer check for them with a similar format with
> it6505_bridge_atomic_enable in ITE IT6505.
> 
> Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
> Fixes: 049723628716 ("drm/bridge: Add ITE IT6263 LVDS to HDMI converter")
> ---
>  drivers/gpu/drm/bridge/ite-it6263.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/bridge/ite-it6263.c b/drivers/gpu/drm/bridge/ite-it6263.c
> index a3a63a977b0a..3a20b2088bf9 100644
> --- a/drivers/gpu/drm/bridge/ite-it6263.c
> +++ b/drivers/gpu/drm/bridge/ite-it6263.c
> @@ -590,15 +590,28 @@ static void it6263_bridge_atomic_enable(struct drm_bridge *bridge,
>  	struct drm_connector *connector;
>  	bool is_stable = false;
>  	struct drm_crtc *crtc;
> +	struct drm_connector_state *conn_state;
>  	unsigned int val;
>  	bool pclk_high;
>  	int i, ret;
>  
>  	connector = drm_atomic_get_new_connector_for_encoder(state,
>  							     bridge->encoder);
> -	crtc = drm_atomic_get_new_connector_state(state, connector)->crtc;
> +	if (WARN_ON(!connector))
> +		return;
> +
> +	conn_state = drm_atomic_get_new_connector_state(state, connector);
> +	if (WARN_ON(!conn_state))
> +		return;
> +
> +	crtc = conn_state->crtc;
>  	crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
> +	if (WARN_ON(!crtc_state))
> +		return;
> +
>  	mode = &crtc_state->adjusted_mode;
> +	if (WARN_ON(!mode))
> +		return;

And that condition can never be true.

Maxime

Apologies for the second email.
I am resending this message as the formatting in the previous version
was incorrect

On Tue, Jul 22, 2025 at 11:57 PM Maxime Ripard <mripard@kernel.org> wrote:
>
> On Tue, Jul 22, 2025 at 03:41:14PM -0500, Chenyuan Yang wrote:
> > drm_atomic_get_new_connector_for_encoder and
> > drm_atomic_get_new_connector_state could return Null.
>
> They can, but not in that scenario. atomic_enable will never be called
> if either would return NULL.
>
> In which situation did you trigger this bug?

This is found by our static analysis tool based on the fact that
drm_atomic_get_new_connector_state() could return NULL.
We also noticed that under the same dir, the ITE IT6505 transmitter
has such checks.
Thus, we assume it would be good to have similar checks here.

> > Thus, add the null pointer check for them with a similar format with
> > it6505_bridge_atomic_enable in ITE IT6505.
> >
> > Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
> > Fixes: 049723628716 ("drm/bridge: Add ITE IT6263 LVDS to HDMI converter")
> > ---
> >  drivers/gpu/drm/bridge/ite-it6263.c | 15 ++++++++++++++-
> >  1 file changed, 14 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/ite-it6263.c b/drivers/gpu/drm/bridge/ite-it6263.c
> > index a3a63a977b0a..3a20b2088bf9 100644
> > --- a/drivers/gpu/drm/bridge/ite-it6263.c
> > +++ b/drivers/gpu/drm/bridge/ite-it6263.c
> > @@ -590,15 +590,28 @@ static void it6263_bridge_atomic_enable(struct drm_bridge *bridge,
> >       struct drm_connector *connector;
> >       bool is_stable = false;
> >       struct drm_crtc *crtc;
> > +     struct drm_connector_state *conn_state;
> >       unsigned int val;
> >       bool pclk_high;
> >       int i, ret;
> >
> >       connector = drm_atomic_get_new_connector_for_encoder(state,
> >                                                            bridge->encoder);
> > -     crtc = drm_atomic_get_new_connector_state(state, connector)->crtc;
> > +     if (WARN_ON(!connector))
> > +             return;
> > +
> > +     conn_state = drm_atomic_get_new_connector_state(state, connector);
> > +     if (WARN_ON(!conn_state))
> > +             return;
> > +
> > +     crtc = conn_state->crtc;
> >       crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
> > +     if (WARN_ON(!crtc_state))
> > +             return;
> > +
> >       mode = &crtc_state->adjusted_mode;
> > +     if (WARN_ON(!mode))
> > +             return;
>
> And that condition can never be true.
>
> Maxime