[PATCH v4 1/3] drm: adv7511: Fix use-after-free in adv7533_attach_dsi()

[PATCH v4 1/3] drm: adv7511: Fix use-after-free in adv7533_attach_dsi()

[Biju Das]

The host_node pointer was assigned and freed in adv7533_parse_dt(), and
later, adv7533_attach_dsi() used the same. Fix this use-after-free issue
with the below changes:

 1. Drop host_node from struct adv7511 and instead use a local pointer in
    adv7511_probe().
 2. Update adv7533_parse_dt() to return the host_node.
 3. Pass the host_node as a parameter to adv7533_attach_dsi().
 4. Call of_node_put() after use.

Fixes: 1e4d58cd7f88 ("drm/bridge: adv7533: Create a MIPI DSI device")
Cc: stable@vger.kernel.org
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
Changes in v4:
 - Updated commit description.
 - Dropped host_node from struct adv7511 and instead used a local pointer
   in probe(). Also freeing of host_node pointer after use is done in
   probe().
Changes in v3:
 - Replace __free construct with readable of_node_put().
Changes in v2:
 - Added the tag "Cc: stable@vger.kernel.org" in the sign-off area.
 - Dropped Archit Taneja invalid Mail address
---
 drivers/gpu/drm/bridge/adv7511/adv7511.h     |  6 +++---
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 22 ++++++++++++++------
 drivers/gpu/drm/bridge/adv7511/adv7533.c     | 20 +++++++++---------
 3 files changed, 29 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h b/drivers/gpu/drm/bridge/adv7511/adv7511.h
index ec0b7f3d889c..9f3fae7cc597 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511.h
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h
@@ -383,7 +383,6 @@ struct adv7511 {
 	struct regulator_bulk_data *supplies;
 
 	/* ADV7533 DSI RX related params */
-	struct device_node *host_node;
 	struct mipi_dsi_device *dsi;
 	u8 num_dsi_lanes;
 	bool use_timing_gen;
@@ -417,8 +416,9 @@ enum drm_mode_status adv7533_mode_valid(struct adv7511 *adv,
 					const struct drm_display_mode *mode);
 int adv7533_patch_registers(struct adv7511 *adv);
 int adv7533_patch_cec_registers(struct adv7511 *adv);
-int adv7533_attach_dsi(struct adv7511 *adv);
-int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv);
+int adv7533_attach_dsi(struct adv7511 *adv, struct device_node *host_node);
+struct device_node *adv7533_parse_dt(struct device_node *np,
+				     struct adv7511 *adv);
 
 #ifdef CONFIG_DRM_I2C_ADV7511_AUDIO
 int adv7511_audio_init(struct device *dev, struct adv7511 *adv7511);
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index eb5919b38263..3f1f309791a5 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -1209,6 +1209,7 @@ static int adv7511_parse_dt(struct device_node *np,
 static int adv7511_probe(struct i2c_client *i2c)
 {
 	struct adv7511_link_config link_config;
+	struct device_node *host_node = NULL;
 	struct adv7511 *adv7511;
 	struct device *dev = &i2c->dev;
 	unsigned int val;
@@ -1233,12 +1234,17 @@ static int adv7511_probe(struct i2c_client *i2c)
 	if (ret && ret != -ENODEV)
 		return ret;
 
-	if (adv7511->info->link_config)
+	if (adv7511->info->link_config) {
 		ret = adv7511_parse_dt(dev->of_node, &link_config);
-	else
-		ret = adv7533_parse_dt(dev->of_node, adv7511);
-	if (ret)
-		return ret;
+		if (ret)
+			return ret;
+	}
+
+	if (adv7511->info->has_dsi) {
+		host_node = adv7533_parse_dt(dev->of_node, adv7511);
+		if (IS_ERR(host_node))
+			return PTR_ERR(host_node);
+	}
 
 	ret = adv7511_init_regulators(adv7511);
 	if (ret)
@@ -1343,9 +1349,11 @@ static int adv7511_probe(struct i2c_client *i2c)
 	}
 
 	if (adv7511->info->has_dsi) {
-		ret = adv7533_attach_dsi(adv7511);
+		ret = adv7533_attach_dsi(adv7511, host_node);
 		if (ret)
 			goto err_unregister_audio;
+
+		of_node_put(host_node);
 	}
 
 	return 0;
@@ -1362,6 +1370,8 @@ static int adv7511_probe(struct i2c_client *i2c)
 err_i2c_unregister_edid:
 	i2c_unregister_device(adv7511->i2c_edid);
 uninit_regulators:
+	if (host_node)
+		of_node_put(host_node);
 	adv7511_uninit_regulators(adv7511);
 
 	return ret;
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7533.c b/drivers/gpu/drm/bridge/adv7511/adv7533.c
index 4481489aaf5e..5d0e55ef4028 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7533.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7533.c
@@ -131,7 +131,7 @@ int adv7533_patch_cec_registers(struct adv7511 *adv)
 				    ARRAY_SIZE(adv7533_cec_fixed_registers));
 }
 
-int adv7533_attach_dsi(struct adv7511 *adv)
+int adv7533_attach_dsi(struct adv7511 *adv, struct device_node *host_node)
 {
 	struct device *dev = &adv->i2c_main->dev;
 	struct mipi_dsi_host *host;
@@ -142,7 +142,7 @@ int adv7533_attach_dsi(struct adv7511 *adv)
 						   .node = NULL,
 						 };
 
-	host = of_find_mipi_dsi_host_by_node(adv->host_node);
+	host = of_find_mipi_dsi_host_by_node(host_node);
 	if (!host)
 		return dev_err_probe(dev, -EPROBE_DEFER,
 				     "failed to find dsi host\n");
@@ -166,22 +166,22 @@ int adv7533_attach_dsi(struct adv7511 *adv)
 	return 0;
 }
 
-int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
+struct device_node *adv7533_parse_dt(struct device_node *np,
+				     struct adv7511 *adv)
 {
+	struct device_node *host_node;
 	u32 num_lanes;
 
 	of_property_read_u32(np, "adi,dsi-lanes", &num_lanes);
 
 	if (num_lanes < 1 || num_lanes > 4)
-		return -EINVAL;
+		return ERR_PTR(-EINVAL);
 
 	adv->num_dsi_lanes = num_lanes;
 
-	adv->host_node = of_graph_get_remote_node(np, 0, 0);
-	if (!adv->host_node)
-		return -ENODEV;
-
-	of_node_put(adv->host_node);
+	host_node = of_graph_get_remote_node(np, 0, 0);
+	if (!host_node)
+		return ERR_PTR(-ENODEV);
 
 	adv->use_timing_gen = !of_property_read_bool(np,
 						"adi,disable-timing-generator");
@@ -190,5 +190,5 @@ int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
 	adv->rgb = true;
 	adv->embedded_sync = false;
 
-	return 0;
+	return host_node;
 }
-- 
2.43.0

[PATCH v4 2/3] dt-bindings: display: adi,adv7533: Drop single lane support

[Biju Das]

As per [1] and [2], ADV7535/7533 supports only 2-, 3-, or 4-lane. Drop
unsupported 1-lane from bindings.

[1] https://www.analog.com/media/en/technical-documentation/data-sheets/ADV7535.pdf
[2] https://www.analog.com/media/en/technical-documentation/data-sheets/ADV7533.pdf

Fixes: 1e4d58cd7f88 ("drm/bridge: adv7533: Create a MIPI DSI device")
Cc: stable@vger.kernel.org
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v3->v4:
 * Added link to ADV7533 data sheet.
 * Collected tags.
v3:
 * New patch.
---
 .../devicetree/bindings/display/bridge/adi,adv7533.yaml         | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/display/bridge/adi,adv7533.yaml b/Documentation/devicetree/bindings/display/bridge/adi,adv7533.yaml
index df20a3c9c744..ec89115c74e4 100644
--- a/Documentation/devicetree/bindings/display/bridge/adi,adv7533.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/adi,adv7533.yaml
@@ -90,7 +90,7 @@ properties:
   adi,dsi-lanes:
     description: Number of DSI data lanes connected to the DSI host.
     $ref: /schemas/types.yaml#/definitions/uint32
-    enum: [ 1, 2, 3, 4 ]
+    enum: [ 2, 3, 4 ]
 
   "#sound-dai-cells":
     const: 0
-- 
2.43.0

[PATCH v4 3/3] drm: adv7511: Drop dsi single lane support

[Biju Das]

As per [1] and [2], ADV7535/7533 supports only 2-, 3-, or 4-lane. Drop
unsupported 1-lane.

[1] https://www.analog.com/media/en/technical-documentation/data-sheets/ADV7535.pdf
[2] https://www.analog.com/media/en/technical-documentation/data-sheets/ADV7533.pdf

Fixes: 1e4d58cd7f88 ("drm/bridge: adv7533: Create a MIPI DSI device")
Reported-by: Hien Huynh <hien.huynh.px@renesas.com>
Cc: stable@vger.kernel.org
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
Changes in v4:
 - Added link to ADV7533 data sheet.
 - Collected tags
Changes in v3:
 - Updated commit header and description
 - Updated fixes tag
 - Dropped single lane support
Changes in v2:
 - Added the tag "Cc: stable@vger.kernel.org" in the sign-off area.
 - Dropped Archit Taneja invalid Mail address
---
 drivers/gpu/drm/bridge/adv7511/adv7533.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7533.c b/drivers/gpu/drm/bridge/adv7511/adv7533.c
index 5d0e55ef4028..51ddd935b568 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7533.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7533.c
@@ -174,7 +174,7 @@ struct device_node *adv7533_parse_dt(struct device_node *np,
 
 	of_property_read_u32(np, "adi,dsi-lanes", &num_lanes);
 
-	if (num_lanes < 1 || num_lanes > 4)
+	if (num_lanes < 2 || num_lanes > 4)
 		return ERR_PTR(-EINVAL);
 
 	adv->num_dsi_lanes = num_lanes;
-- 
2.43.0

Re: [PATCH v4 1/3] drm: adv7511: Fix use-after-free in adv7533_attach_dsi()

[Laurent Pinchart]

Hi Biju,

Thank you for the patch.

On Sat, Nov 16, 2024 at 12:54:10PM +0000, Biju Das wrote:
> The host_node pointer was assigned and freed in adv7533_parse_dt(), and
> later, adv7533_attach_dsi() used the same. Fix this use-after-free issue
> with the below changes:
> 
>  1. Drop host_node from struct adv7511 and instead use a local pointer in
>     adv7511_probe().
>  2. Update adv7533_parse_dt() to return the host_node.
>  3. Pass the host_node as a parameter to adv7533_attach_dsi().
>  4. Call of_node_put() after use.
> 
> Fixes: 1e4d58cd7f88 ("drm/bridge: adv7533: Create a MIPI DSI device")
> Cc: stable@vger.kernel.org
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> Changes in v4:
>  - Updated commit description.
>  - Dropped host_node from struct adv7511 and instead used a local pointer
>    in probe(). Also freeing of host_node pointer after use is done in
>    probe().
> Changes in v3:
>  - Replace __free construct with readable of_node_put().
> Changes in v2:
>  - Added the tag "Cc: stable@vger.kernel.org" in the sign-off area.
>  - Dropped Archit Taneja invalid Mail address
> ---
>  drivers/gpu/drm/bridge/adv7511/adv7511.h     |  6 +++---
>  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 22 ++++++++++++++------
>  drivers/gpu/drm/bridge/adv7511/adv7533.c     | 20 +++++++++---------
>  3 files changed, 29 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h b/drivers/gpu/drm/bridge/adv7511/adv7511.h
> index ec0b7f3d889c..9f3fae7cc597 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511.h
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h
> @@ -383,7 +383,6 @@ struct adv7511 {
>  	struct regulator_bulk_data *supplies;
>  
>  	/* ADV7533 DSI RX related params */
> -	struct device_node *host_node;
>  	struct mipi_dsi_device *dsi;
>  	u8 num_dsi_lanes;
>  	bool use_timing_gen;
> @@ -417,8 +416,9 @@ enum drm_mode_status adv7533_mode_valid(struct adv7511 *adv,
>  					const struct drm_display_mode *mode);
>  int adv7533_patch_registers(struct adv7511 *adv);
>  int adv7533_patch_cec_registers(struct adv7511 *adv);
> -int adv7533_attach_dsi(struct adv7511 *adv);
> -int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv);
> +int adv7533_attach_dsi(struct adv7511 *adv, struct device_node *host_node);
> +struct device_node *adv7533_parse_dt(struct device_node *np,
> +				     struct adv7511 *adv);
>  
>  #ifdef CONFIG_DRM_I2C_ADV7511_AUDIO
>  int adv7511_audio_init(struct device *dev, struct adv7511 *adv7511);
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> index eb5919b38263..3f1f309791a5 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> @@ -1209,6 +1209,7 @@ static int adv7511_parse_dt(struct device_node *np,
>  static int adv7511_probe(struct i2c_client *i2c)
>  {
>  	struct adv7511_link_config link_config;
> +	struct device_node *host_node = NULL;
>  	struct adv7511 *adv7511;
>  	struct device *dev = &i2c->dev;
>  	unsigned int val;
> @@ -1233,12 +1234,17 @@ static int adv7511_probe(struct i2c_client *i2c)
>  	if (ret && ret != -ENODEV)
>  		return ret;
>  
> -	if (adv7511->info->link_config)
> +	if (adv7511->info->link_config) {
>  		ret = adv7511_parse_dt(dev->of_node, &link_config);
> -	else
> -		ret = adv7533_parse_dt(dev->of_node, adv7511);
> -	if (ret)
> -		return ret;
> +		if (ret)
> +			return ret;
> +	}
> +
> +	if (adv7511->info->has_dsi) {
> +		host_node = adv7533_parse_dt(dev->of_node, adv7511);
> +		if (IS_ERR(host_node))
> +			return PTR_ERR(host_node);
> +	}
>  
>  	ret = adv7511_init_regulators(adv7511);
>  	if (ret)

host_node is leaked here.

> @@ -1343,9 +1349,11 @@ static int adv7511_probe(struct i2c_client *i2c)
>  	}
>  
>  	if (adv7511->info->has_dsi) {
> -		ret = adv7533_attach_dsi(adv7511);
> +		ret = adv7533_attach_dsi(adv7511, host_node);
>  		if (ret)
>  			goto err_unregister_audio;
> +
> +		of_node_put(host_node);
>  	}
>  
>  	return 0;
> @@ -1362,6 +1370,8 @@ static int adv7511_probe(struct i2c_client *i2c)
>  err_i2c_unregister_edid:
>  	i2c_unregister_device(adv7511->i2c_edid);
>  uninit_regulators:
> +	if (host_node)
> +		of_node_put(host_node);

The error label and the error handling code are now out of sync, making
the code harder to read and more error-prone.

Error handling is why I proposed keeping of_node in the adv7511
structure, and calling of_node_put() in adv7511_remove() and at the end
of the error handling path in adv7511_probe().

>  	adv7511_uninit_regulators(adv7511);
>  
>  	return ret;
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7533.c b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> index 4481489aaf5e..5d0e55ef4028 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7533.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> @@ -131,7 +131,7 @@ int adv7533_patch_cec_registers(struct adv7511 *adv)
>  				    ARRAY_SIZE(adv7533_cec_fixed_registers));
>  }
>  
> -int adv7533_attach_dsi(struct adv7511 *adv)
> +int adv7533_attach_dsi(struct adv7511 *adv, struct device_node *host_node)
>  {
>  	struct device *dev = &adv->i2c_main->dev;
>  	struct mipi_dsi_host *host;
> @@ -142,7 +142,7 @@ int adv7533_attach_dsi(struct adv7511 *adv)
>  						   .node = NULL,
>  						 };
>  
> -	host = of_find_mipi_dsi_host_by_node(adv->host_node);
> +	host = of_find_mipi_dsi_host_by_node(host_node);
>  	if (!host)
>  		return dev_err_probe(dev, -EPROBE_DEFER,
>  				     "failed to find dsi host\n");
> @@ -166,22 +166,22 @@ int adv7533_attach_dsi(struct adv7511 *adv)
>  	return 0;
>  }
>  
> -int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
> +struct device_node *adv7533_parse_dt(struct device_node *np,
> +				     struct adv7511 *adv)
>  {
> +	struct device_node *host_node;
>  	u32 num_lanes;
>  
>  	of_property_read_u32(np, "adi,dsi-lanes", &num_lanes);
>  
>  	if (num_lanes < 1 || num_lanes > 4)
> -		return -EINVAL;
> +		return ERR_PTR(-EINVAL);
>  
>  	adv->num_dsi_lanes = num_lanes;
>  
> -	adv->host_node = of_graph_get_remote_node(np, 0, 0);
> -	if (!adv->host_node)
> -		return -ENODEV;
> -
> -	of_node_put(adv->host_node);
> +	host_node = of_graph_get_remote_node(np, 0, 0);
> +	if (!host_node)
> +		return ERR_PTR(-ENODEV);
>  
>  	adv->use_timing_gen = !of_property_read_bool(np,
>  						"adi,disable-timing-generator");
> @@ -190,5 +190,5 @@ int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
>  	adv->rgb = true;
>  	adv->embedded_sync = false;
>  
> -	return 0;
> +	return host_node;
>  }

-- 
Regards,

Laurent Pinchart

RE: [PATCH v4 1/3] drm: adv7511: Fix use-after-free in adv7533_attach_dsi()

[Biju Das]

Hi Laurent,


Thanks for the feedback.

> -----Original Message-----
> From: dri-devel <dri-devel-bounces@lists.freedesktop.org> On Behalf Of Laurent Pinchart
> Sent: 16 November 2024 15:32
> Subject: Re: [PATCH v4 1/3] drm: adv7511: Fix use-after-free in adv7533_attach_dsi()
> 
> Hi Biju,
> 
> Thank you for the patch.
> 
> On Sat, Nov 16, 2024 at 12:54:10PM +0000, Biju Das wrote:
> > The host_node pointer was assigned and freed in adv7533_parse_dt(),
> > and later, adv7533_attach_dsi() used the same. Fix this use-after-free
> > issue with the below changes:
> >
> >  1. Drop host_node from struct adv7511 and instead use a local pointer in
> >     adv7511_probe().
> >  2. Update adv7533_parse_dt() to return the host_node.
> >  3. Pass the host_node as a parameter to adv7533_attach_dsi().
> >  4. Call of_node_put() after use.
> >
> > Fixes: 1e4d58cd7f88 ("drm/bridge: adv7533: Create a MIPI DSI device")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > ---
> > Changes in v4:
> >  - Updated commit description.
> >  - Dropped host_node from struct adv7511 and instead used a local pointer
> >    in probe(). Also freeing of host_node pointer after use is done in
> >    probe().
> > Changes in v3:
> >  - Replace __free construct with readable of_node_put().
> > Changes in v2:
> >  - Added the tag "Cc: stable@vger.kernel.org" in the sign-off area.
> >  - Dropped Archit Taneja invalid Mail address
> > ---
> >  drivers/gpu/drm/bridge/adv7511/adv7511.h     |  6 +++---
> >  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 22 ++++++++++++++------
> >  drivers/gpu/drm/bridge/adv7511/adv7533.c     | 20 +++++++++---------
> >  3 files changed, 29 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h
> > b/drivers/gpu/drm/bridge/adv7511/adv7511.h
> > index ec0b7f3d889c..9f3fae7cc597 100644
> > --- a/drivers/gpu/drm/bridge/adv7511/adv7511.h
> > +++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h
> > @@ -383,7 +383,6 @@ struct adv7511 {
> >  	struct regulator_bulk_data *supplies;
> >
> >  	/* ADV7533 DSI RX related params */
> > -	struct device_node *host_node;
> >  	struct mipi_dsi_device *dsi;
> >  	u8 num_dsi_lanes;
> >  	bool use_timing_gen;
> > @@ -417,8 +416,9 @@ enum drm_mode_status adv7533_mode_valid(struct adv7511 *adv,
> >  					const struct drm_display_mode *mode);  int
> > adv7533_patch_registers(struct adv7511 *adv);  int
> > adv7533_patch_cec_registers(struct adv7511 *adv); -int
> > adv7533_attach_dsi(struct adv7511 *adv); -int adv7533_parse_dt(struct
> > device_node *np, struct adv7511 *adv);
> > +int adv7533_attach_dsi(struct adv7511 *adv, struct device_node
> > +*host_node); struct device_node *adv7533_parse_dt(struct device_node *np,
> > +				     struct adv7511 *adv);
> >
> >  #ifdef CONFIG_DRM_I2C_ADV7511_AUDIO
> >  int adv7511_audio_init(struct device *dev, struct adv7511 *adv7511);
> > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > index eb5919b38263..3f1f309791a5 100644
> > --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > @@ -1209,6 +1209,7 @@ static int adv7511_parse_dt(struct device_node
> > *np,  static int adv7511_probe(struct i2c_client *i2c)  {
> >  	struct adv7511_link_config link_config;
> > +	struct device_node *host_node = NULL;
> >  	struct adv7511 *adv7511;
> >  	struct device *dev = &i2c->dev;
> >  	unsigned int val;
> > @@ -1233,12 +1234,17 @@ static int adv7511_probe(struct i2c_client *i2c)
> >  	if (ret && ret != -ENODEV)
> >  		return ret;
> >
> > -	if (adv7511->info->link_config)
> > +	if (adv7511->info->link_config) {
> >  		ret = adv7511_parse_dt(dev->of_node, &link_config);
> > -	else
> > -		ret = adv7533_parse_dt(dev->of_node, adv7511);
> > -	if (ret)
> > -		return ret;
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	if (adv7511->info->has_dsi) {
> > +		host_node = adv7533_parse_dt(dev->of_node, adv7511);
> > +		if (IS_ERR(host_node))
> > +			return PTR_ERR(host_node);
> > +	}
> >
> >  	ret = adv7511_init_regulators(adv7511);
> >  	if (ret)
> 
> host_node is leaked here.

Oops. Missed it.
> 
> > @@ -1343,9 +1349,11 @@ static int adv7511_probe(struct i2c_client *i2c)
> >  	}
> >
> >  	if (adv7511->info->has_dsi) {
> > -		ret = adv7533_attach_dsi(adv7511);
> > +		ret = adv7533_attach_dsi(adv7511, host_node);
> >  		if (ret)
> >  			goto err_unregister_audio;
> > +
> > +		of_node_put(host_node);
> >  	}
> >
> >  	return 0;
> > @@ -1362,6 +1370,8 @@ static int adv7511_probe(struct i2c_client *i2c)
> >  err_i2c_unregister_edid:
> >  	i2c_unregister_device(adv7511->i2c_edid);
> >  uninit_regulators:
> > +	if (host_node)
> > +		of_node_put(host_node);
> 
> The error label and the error handling code are now out of sync, making the code harder to read and
> more error-prone.
> 
> Error handling is why I proposed keeping of_node in the adv7511 structure, and calling of_node_put()
> in adv7511_remove() and at the end of the error handling path in adv7511_probe().

OK got it, Then will keep the of_node in the adv7511 structure to make the error label and 
error handling code in sync.

Cheers,
Biju

> 
> >  	adv7511_uninit_regulators(adv7511);
> >
> >  	return ret;
> > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7533.c
> > b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> > index 4481489aaf5e..5d0e55ef4028 100644
> > --- a/drivers/gpu/drm/bridge/adv7511/adv7533.c
> > +++ b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> > @@ -131,7 +131,7 @@ int adv7533_patch_cec_registers(struct adv7511 *adv)
> >  				    ARRAY_SIZE(adv7533_cec_fixed_registers));
> >  }
> >
> > -int adv7533_attach_dsi(struct adv7511 *adv)
> > +int adv7533_attach_dsi(struct adv7511 *adv, struct device_node
> > +*host_node)
> >  {
> >  	struct device *dev = &adv->i2c_main->dev;
> >  	struct mipi_dsi_host *host;
> > @@ -142,7 +142,7 @@ int adv7533_attach_dsi(struct adv7511 *adv)
> >  						   .node = NULL,
> >  						 };
> >
> > -	host = of_find_mipi_dsi_host_by_node(adv->host_node);
> > +	host = of_find_mipi_dsi_host_by_node(host_node);
> >  	if (!host)
> >  		return dev_err_probe(dev, -EPROBE_DEFER,
> >  				     "failed to find dsi host\n"); @@ -166,22 +166,22 @@ int
> > adv7533_attach_dsi(struct adv7511 *adv)
> >  	return 0;
> >  }
> >
> > -int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
> > +struct device_node *adv7533_parse_dt(struct device_node *np,
> > +				     struct adv7511 *adv)
> >  {
> > +	struct device_node *host_node;
> >  	u32 num_lanes;
> >
> >  	of_property_read_u32(np, "adi,dsi-lanes", &num_lanes);
> >
> >  	if (num_lanes < 1 || num_lanes > 4)
> > -		return -EINVAL;
> > +		return ERR_PTR(-EINVAL);
> >
> >  	adv->num_dsi_lanes = num_lanes;
> >
> > -	adv->host_node = of_graph_get_remote_node(np, 0, 0);
> > -	if (!adv->host_node)
> > -		return -ENODEV;
> > -
> > -	of_node_put(adv->host_node);
> > +	host_node = of_graph_get_remote_node(np, 0, 0);
> > +	if (!host_node)
> > +		return ERR_PTR(-ENODEV);
> >
> >  	adv->use_timing_gen = !of_property_read_bool(np,
> >  						"adi,disable-timing-generator"); @@ -190,5 +190,5 @@ int
> > adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
> >  	adv->rgb = true;
> >  	adv->embedded_sync = false;
> >
> > -	return 0;
> > +	return host_node;
> >  }
> 
> --
> Regards,
> 
> Laurent Pinchart