[PATCH] Gpu: drm: exynos - Fix possible NULL derefrence.

[PATCH] Gpu: drm: exynos - Fix possible NULL derefrence.

[Shailendra Verma]

of_device_get_match_data could return NULL, and so can cause
a NULL pointer dereference later.

Signed-off-by: Shailendra Verma <shailendra.v@samsung.com>
---
 drivers/gpu/drm/exynos/exynos_drm_dsi.c  |    4 ++++
 drivers/gpu/drm/exynos/exynos_drm_fimd.c |    4 ++++
 drivers/gpu/drm/exynos/exynos_hdmi.c     |    4 ++++
 drivers/gpu/drm/exynos/exynos_mixer.c    |    4 ++++
 4 files changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index e07cb1f..fba0ffc 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -1765,6 +1765,10 @@ static int exynos_dsi_probe(struct platform_device *pdev)
 
 	dsi->dev = dev;
 	dsi->driver_data = of_device_get_match_data(dev);
+	if (!dsi->driver_data) {
+		dev_err(dev, "no device match found\n");
+		return -ENODEV;
+	}
 
 	ret = exynos_dsi_parse_dt(dsi);
 	if (ret)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index e2e4051..f568234 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -1076,6 +1076,10 @@ static int fimd_probe(struct platform_device *pdev)
 	ctx->dev = dev;
 	ctx->suspended = true;
 	ctx->driver_data = of_device_get_match_data(dev);
+	if (!ctx->driver_data) {
+		dev_err(dev, "no device match found\n");
+		return -ENODEV;
+	}
 
 	if (of_property_read_bool(dev->of_node, "samsung,invert-vden"))
 		ctx->vidcon1 |= VIDCON1_INV_VDEN;
diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index 38eaa63..27aeb74 100644
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -1837,6 +1837,10 @@ static int hdmi_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	hdata->drv_data = of_device_get_match_data(dev);
+	if (!hdata->drv_data) {
+		dev_err(dev, "no device match found\n");
+		return -ENODEV;
+	}
 
 	platform_set_drvdata(pdev, hdata);
 
diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
index edb20a3..b3c6bbb 100644
--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -1205,6 +1205,10 @@ static int mixer_probe(struct platform_device *pdev)
 	}
 
 	drv = of_device_get_match_data(dev);
+	if (!drv) {
+		dev_err(dev, "no device match found\n");
+		return -ENODEV;
+	}
 
 	ctx->pdev = pdev;
 	ctx->dev = dev;
-- 
1.7.9.5

Re: [PATCH] Gpu: drm: exynos - Fix possible NULL derefrence.

[Javier Martinez Canillas]

Hello Shailendra,

The subject line is wrong, please always use the convention used in
previous commits, i.e: git log --oneline drivers/gpu/drm/exynos/

On 01/30/2017 02:02 AM, Shailendra Verma wrote:
> of_device_get_match_data could return NULL, and so can cause
> a NULL pointer dereference later.
> 
> Signed-off-by: Shailendra Verma <shailendra.v@samsung.com>
> ---
>  drivers/gpu/drm/exynos/exynos_drm_dsi.c  |    4 ++++
>  drivers/gpu/drm/exynos/exynos_drm_fimd.c |    4 ++++
>  drivers/gpu/drm/exynos/exynos_hdmi.c     |    4 ++++
>  drivers/gpu/drm/exynos/exynos_mixer.c    |    4 ++++
>  4 files changed, 16 insertions(+)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> index e07cb1f..fba0ffc 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> @@ -1765,6 +1765,10 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>  
>  	dsi->dev = dev;
>  	dsi->driver_data = of_device_get_match_data(dev);
> +	if (!dsi->driver_data) {
> +		dev_err(dev, "no device match found\n");
> +		return -ENODEV;
> +	}
>

I don't think this makes sense for the Exynos driver since Exynos is a
DT-only platform and so the probe callback can only be called if a dev
node with a compatible string in the OF device id table was registered.

All the struct of_device_id in the table have a .data and so this can't
be NULL in this driver.
 
Best regards,
-- 
Javier Martinez Canillas
Open Source Group
Samsung Research America