[Intel-gfx] [PATCH 1/5] Fixing Possible Null Pointer Dereference

[Shankar, Uma]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Ville
> Syrjälä
> Sent: Tuesday, August 25, 2020 1:29 AM
> To: Varide, Nischal <nischal.varide at intel.com>
> Cc: intel-gfx at lists.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH 1/5] Fixing Possible Null Pointer Dereference
> 
> On Mon, Aug 24, 2020 at 09:15:52AM +0530, Nischal Varide wrote:
> > There is a possble Null Pointer dereference in intel_atomic.c and this
> > patch fixes the same by introducting a check to old_state, new_state
> > old_conn_state and new_conn_state variables.
> 
> Not possible. In fact none of the supposed null ptrs in the series seem possible
> to me.

Hi Nischal,
Yeah I agree with Ville, these all seem to be false positives. We don't expect these to be NULL at this deep in the
call flow. You can drop these.

Regards,
Uma Shankar

> >
> > Signed-off-by: Nischal Varide <nischal.varide at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_atomic.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c
> > b/drivers/gpu/drm/i915/display/intel_atomic.c
> > index 630f49b7aa01..ab58f061c8a7 100644
> > --- a/drivers/gpu/drm/i915/display/intel_atomic.c
> > +++ b/drivers/gpu/drm/i915/display/intel_atomic.c
> > @@ -132,6 +132,9 @@ int intel_digital_connector_atomic_check(struct
> drm_connector *conn,
> >  		to_intel_digital_connector_state(old_state);
> >  	struct drm_crtc_state *crtc_state;
> >
> > +	if (!(new_state && new_conn_state && old_state && old_conn_state))
> > +		return 0;
> > +
> >  	intel_hdcp_atomic_check(conn, old_state, new_state);
> >  	intel_psr_atomic_check(conn, old_state, new_state);
> >
> > @@ -192,6 +195,8 @@ intel_connector_needs_modeset(struct
> > intel_atomic_state *state,
> >
> >  	old_conn_state = drm_atomic_get_old_connector_state(&state->base,
> connector);
> >  	new_conn_state = drm_atomic_get_new_connector_state(&state->base,
> > connector);
> > +	if (!(old_conn_state && new_conn_state))
> > +		return 0;
> >
> >  	return old_conn_state->crtc != new_conn_state->crtc ||
> >  	       (new_conn_state->crtc &&
> > --
> > 2.26.0
> >
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> > Intel-gfx at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> --
> Ville Syrjälä
> Intel
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