[PATCH] drm/msm/dpu: Add a null ptr check for dpu_encoder_needs_modeset

[Chenyuan Yang]

On Wed, Jul 23, 2025 at 12:05 PM Dmitry Baryshkov
<dmitry.baryshkov at oss.qualcomm.com> wrote:
>
> On Tue, Jul 22, 2025 at 04:17:40PM -0500, Chenyuan Yang wrote:
> > The drm_atomic_get_new_connector_state() can return NULL if the
> > connector is not part of the atomic state. Add a check to prevent
> > a NULL pointer dereference.
> >
> > This follows the same pattern used in dpu_encoder_update_topology()
> > within the same file, which checks for NULL before using conn_state.
> >
> > Signed-off-by: Chenyuan Yang <chenyuan0y at gmail.com>
> > Fixes: 1ce69c265a53 ("drm/msm/dpu: move resource allocation to CRTC")
> > ---
> >  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > index c0ed110a7d30..4bddb9504796 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> > @@ -729,6 +729,8 @@ bool dpu_encoder_needs_modeset(struct drm_encoder *drm_enc, struct drm_atomic_st
> >               return false;
> >
> >       conn_state = drm_atomic_get_new_connector_state(state, connector);
> > +     if (!conn_state)
> > +             return false;
>
> Did this happen in a real case or is it just
> yet-another-static-analysys?

This is a static-analysis detected bug.

> >
> >       /**
> >        * These checks are duplicated from dpu_encoder_update_topology() since
> > --
> > 2.34.1
> >
>
> --
> With best wishes
> Dmitry