[PATCH] drm/rcar-du: Fix error check when retrieving crtc state

[PATCH] drm/rcar-du: Fix error check when retrieving crtc state

[Sean Paul]

From: Sean Paul <seanpaul@chromium.org>

drm_atomic_get_crtc_state() returns an error pointer when it fails, so
the null check is doing nothing here.

Credit to 0-day/Dan Carpenter for reporting this.

Fixes: 6f3b62781bbd ("drm: Convert connector_helper_funcs->atomic_check to accept drm_atomic_state")
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> [for rcar lvds]
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Karol Herbst <karolherbst@gmail.com>
Cc: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: dri-devel@lists.freedesktop.org
Cc: intel-gfx@lists.freedesktop.org
Cc: linux-renesas-soc@vger.kernel.org
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 drivers/gpu/drm/rcar-du/rcar_lvds.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
index f2a5d4d997073..1c62578590f46 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -115,8 +115,8 @@ static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
 
 	/* We're not allowed to modify the resolution. */
 	crtc_state = drm_atomic_get_crtc_state(state, conn_state->crtc);
-	if (!crtc_state)
-		return -EINVAL;
+	if (IS_ERR(crtc_state))
+		return PTR_ERR(crtc_state);
 
 	if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
 	    crtc_state->mode.vdisplay != panel_mode->vdisplay)
-- 
Sean Paul, Software Engineer, Google / Chromium OS

Re: [PATCH] drm/rcar-du: Fix error check when retrieving crtc state

[Laurent Pinchart]

Hi Sean,

Thank you for the patch.

On Mon, Jun 17, 2019 at 02:15:42PM -0400, Sean Paul wrote:
> From: Sean Paul <seanpaul@chromium.org>
> 
> drm_atomic_get_crtc_state() returns an error pointer when it fails, so
> the null check is doing nothing here.
> 
> Credit to 0-day/Dan Carpenter for reporting this.
> 
> Fixes: 6f3b62781bbd ("drm: Convert connector_helper_funcs->atomic_check to accept drm_atomic_state")
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Ben Skeggs <bskeggs@redhat.com>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> Cc: Eric Anholt <eric@anholt.net>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> [for rcar lvds]
> Cc: Sean Paul <seanpaul@chromium.org>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Maxime Ripard <maxime.ripard@bootlin.com>
> Cc: Sean Paul <sean@poorly.run>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Lyude Paul <lyude@redhat.com>
> Cc: Karol Herbst <karolherbst@gmail.com>
> Cc: Ilia Mirkin <imirkin@alum.mit.edu>
> Cc: dri-devel@lists.freedesktop.org
> Cc: intel-gfx@lists.freedesktop.org
> Cc: linux-renesas-soc@vger.kernel.org
> Reported-by: kbuild test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

I have no pending conflicting changes for rcar_lvds.c. Do you plan to
merge this through drm-misc ?

> ---
>  drivers/gpu/drm/rcar-du/rcar_lvds.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> index f2a5d4d997073..1c62578590f46 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> @@ -115,8 +115,8 @@ static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
>  
>  	/* We're not allowed to modify the resolution. */
>  	crtc_state = drm_atomic_get_crtc_state(state, conn_state->crtc);
> -	if (!crtc_state)
> -		return -EINVAL;
> +	if (IS_ERR(crtc_state))
> +		return PTR_ERR(crtc_state);
>  
>  	if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
>  	    crtc_state->mode.vdisplay != panel_mode->vdisplay)

-- 
Regards,

Laurent Pinchart

Re: [PATCH] drm/rcar-du: Fix error check when retrieving crtc state

[Sean Paul]

On Tue, Jun 18, 2019 at 10:26:52AM +0300, Laurent Pinchart wrote:
> Hi Sean,
> 
> Thank you for the patch.
> 
> On Mon, Jun 17, 2019 at 02:15:42PM -0400, Sean Paul wrote:
> > From: Sean Paul <seanpaul@chromium.org>
> > 
> > drm_atomic_get_crtc_state() returns an error pointer when it fails, so
> > the null check is doing nothing here.
> > 
> > Credit to 0-day/Dan Carpenter for reporting this.
> > 
> > Fixes: 6f3b62781bbd ("drm: Convert connector_helper_funcs->atomic_check to accept drm_atomic_state")
> > Cc: Daniel Vetter <daniel@ffwll.ch>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Jani Nikula <jani.nikula@linux.intel.com>
> > Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Cc: Ben Skeggs <bskeggs@redhat.com>
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> > Cc: Eric Anholt <eric@anholt.net>
> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> [for rcar lvds]
> > Cc: Sean Paul <seanpaul@chromium.org>
> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Maxime Ripard <maxime.ripard@bootlin.com>
> > Cc: Sean Paul <sean@poorly.run>
> > Cc: David Airlie <airlied@linux.ie>
> > Cc: Lyude Paul <lyude@redhat.com>
> > Cc: Karol Herbst <karolherbst@gmail.com>
> > Cc: Ilia Mirkin <imirkin@alum.mit.edu>
> > Cc: dri-devel@lists.freedesktop.org
> > Cc: intel-gfx@lists.freedesktop.org
> > Cc: linux-renesas-soc@vger.kernel.org
> > Reported-by: kbuild test robot <lkp@intel.com>
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> I have no pending conflicting changes for rcar_lvds.c. Do you plan to
> merge this through drm-misc ?

Thanks for your review!

Yeah, since the bug is only in drm-misc-next, this will also go there. Speaking
of which, I just applied it :-)

Sean

> 
> > ---
> >  drivers/gpu/drm/rcar-du/rcar_lvds.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > index f2a5d4d997073..1c62578590f46 100644
> > --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> > @@ -115,8 +115,8 @@ static int rcar_lvds_connector_atomic_check(struct drm_connector *connector,
> >  
> >  	/* We're not allowed to modify the resolution. */
> >  	crtc_state = drm_atomic_get_crtc_state(state, conn_state->crtc);
> > -	if (!crtc_state)
> > -		return -EINVAL;
> > +	if (IS_ERR(crtc_state))
> > +		return PTR_ERR(crtc_state);
> >  
> >  	if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
> >  	    crtc_state->mode.vdisplay != panel_mode->vdisplay)
> 
> -- 
> Regards,
> 
> Laurent Pinchart

-- 
Sean Paul, Software Engineer, Google / Chromium OS