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 <mrip...@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 <chenyua...@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
