* [PATCH] drm/bridge: imx: fix potential NULL pointer dereference in imx8qxp_ldb_parse_dt_companion()
@ 2023-08-28 16:55 Zhang Shurong
2023-08-28 17:28 ` Laurent Pinchart
0 siblings, 1 reply; 5+ messages in thread
From: Zhang Shurong @ 2023-08-28 16:55 UTC (permalink / raw)
To: victor.liu
Cc: andrzej.hajda, neil.armstrong, rfoss, Laurent.pinchart, jonas,
jernej.skrabec, airlied, daniel, shawnguo, s.hauer, kernel,
festevam, linux-imx, dri-devel, linux-arm-kernel, linux-kernel,
Zhang Shurong
of_match_device() may fail and returns a NULL pointer.
Fix this by checking the return value of of_match_device().
Fixes: 3818715f62b4 ("drm/bridge: imx: Add LDB support for i.MX8qxp")
Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
---
drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
index 7984da9c0a35..d272f35c8eac 100644
--- a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
+++ b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
@@ -488,6 +488,8 @@ static int imx8qxp_ldb_parse_dt_companion(struct imx8qxp_ldb *imx8qxp_ldb)
* string.
*/
match = of_match_device(dev->driver->of_match_table, dev);
+ if (!match)
+ return -ENODEV;
if (!of_device_is_compatible(companion, match->compatible)) {
DRM_DEV_ERROR(dev, "companion LDB is incompatible\n");
ret = -ENXIO;
--
2.30.2
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] drm/bridge: imx: fix potential NULL pointer dereference in imx8qxp_ldb_parse_dt_companion()
2023-08-28 16:55 [PATCH] drm/bridge: imx: fix potential NULL pointer dereference in imx8qxp_ldb_parse_dt_companion() Zhang Shurong
@ 2023-08-28 17:28 ` Laurent Pinchart
2023-08-28 18:01 ` Zhang Shurong
0 siblings, 1 reply; 5+ messages in thread
From: Laurent Pinchart @ 2023-08-28 17:28 UTC (permalink / raw)
To: Zhang Shurong
Cc: victor.liu, andrzej.hajda, neil.armstrong, rfoss, jonas,
jernej.skrabec, airlied, daniel, shawnguo, s.hauer, kernel,
festevam, linux-imx, dri-devel, linux-arm-kernel, linux-kernel
Hi Zhang,
Thank you for the patch.
On Tue, Aug 29, 2023 at 12:55:01AM +0800, Zhang Shurong wrote:
> of_match_device() may fail and returns a NULL pointer.
How can it return a NULL pointer here ?
> Fix this by checking the return value of of_match_device().
>
> Fixes: 3818715f62b4 ("drm/bridge: imx: Add LDB support for i.MX8qxp")
> Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
> ---
> drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> index 7984da9c0a35..d272f35c8eac 100644
> --- a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> +++ b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> @@ -488,6 +488,8 @@ static int imx8qxp_ldb_parse_dt_companion(struct imx8qxp_ldb *imx8qxp_ldb)
> * string.
> */
> match = of_match_device(dev->driver->of_match_table, dev);
> + if (!match)
> + return -ENODEV;
> if (!of_device_is_compatible(companion, match->compatible)) {
> DRM_DEV_ERROR(dev, "companion LDB is incompatible\n");
> ret = -ENXIO;
--
Regards,
Laurent Pinchart
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] drm/bridge: imx: fix potential NULL pointer dereference in imx8qxp_ldb_parse_dt_companion()
2023-08-28 17:28 ` Laurent Pinchart
@ 2023-08-28 18:01 ` Zhang Shurong
2023-08-28 18:37 ` Laurent Pinchart
0 siblings, 1 reply; 5+ messages in thread
From: Zhang Shurong @ 2023-08-28 18:01 UTC (permalink / raw)
To: Laurent Pinchart
Cc: victor.liu, andrzej.hajda, neil.armstrong, rfoss, jonas,
jernej.skrabec, airlied, daniel, shawnguo, s.hauer, kernel,
festevam, linux-imx, dri-devel, linux-arm-kernel, linux-kernel
在 2023年8月29日星期二 CST 上午1:28:22，Laurent Pinchart 写道：
> Hi Zhang,
>
> Thank you for the patch.
>
> On Tue, Aug 29, 2023 at 12:55:01AM +0800, Zhang Shurong wrote:
> > of_match_device() may fail and returns a NULL pointer.
>
> How can it return a NULL pointer here ?
>
> > Fix this by checking the return value of of_match_device().
> >
> > Fixes: 3818715f62b4 ("drm/bridge: imx: Add LDB support for i.MX8qxp")
> > Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
> > ---
> >
> > drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> > b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c index
> > 7984da9c0a35..d272f35c8eac 100644
> > --- a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> > +++ b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> > @@ -488,6 +488,8 @@ static int imx8qxp_ldb_parse_dt_companion(struct
> > imx8qxp_ldb *imx8qxp_ldb)>
> > * string.
> > */
> >
> > match = of_match_device(dev->driver->of_match_table, dev);
> >
> > + if (!match)
> > + return -ENODEV;
> >
> > if (!of_device_is_compatible(companion, match->compatible)) {
> >
> > DRM_DEV_ERROR(dev, "companion LDB is incompatible\n");
> > ret = -ENXIO;
I think we can make it happen by designing the platform device in a way that
its name aligns with that of the driver. In such a scenario, when the driver
is probed, the of_match_device function will return null. You can verify this
functionality by reviewing the following function:
static int platform_match(struct device *dev, struct device_driver *drv)
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] drm/bridge: imx: fix potential NULL pointer dereference in imx8qxp_ldb_parse_dt_companion()
2023-08-28 18:01 ` Zhang Shurong
@ 2023-08-28 18:37 ` Laurent Pinchart
2023-08-29 2:28 ` Ying Liu
0 siblings, 1 reply; 5+ messages in thread
From: Laurent Pinchart @ 2023-08-28 18:37 UTC (permalink / raw)
To: Zhang Shurong
Cc: victor.liu, andrzej.hajda, neil.armstrong, rfoss, jonas,
jernej.skrabec, airlied, daniel, shawnguo, s.hauer, kernel,
festevam, linux-imx, dri-devel, linux-arm-kernel, linux-kernel
On Tue, Aug 29, 2023 at 02:01:25AM +0800, Zhang Shurong wrote:
> 在 2023年8月29日星期二 CST 上午1:28:22，Laurent Pinchart 写道：
> > Hi Zhang,
> >
> > Thank you for the patch.
> >
> > On Tue, Aug 29, 2023 at 12:55:01AM +0800, Zhang Shurong wrote:
> > > of_match_device() may fail and returns a NULL pointer.
> >
> > How can it return a NULL pointer here ?
> >
> > > Fix this by checking the return value of of_match_device().
> > >
> > > Fixes: 3818715f62b4 ("drm/bridge: imx: Add LDB support for i.MX8qxp")
> > > Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
> > > ---
> > >
> > > drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> > > b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c index
> > > 7984da9c0a35..d272f35c8eac 100644
> > > --- a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> > > +++ b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> > > @@ -488,6 +488,8 @@ static int imx8qxp_ldb_parse_dt_companion(struct imx8qxp_ldb *imx8qxp_ldb)
> > > * string.
> > > */
> > > match = of_match_device(dev->driver->of_match_table, dev);
> > > + if (!match)
> > > + return -ENODEV;
> > > if (!of_device_is_compatible(companion, match->compatible)) {
> > > DRM_DEV_ERROR(dev, "companion LDB is incompatible\n");
> > > ret = -ENXIO;
>
> I think we can make it happen by designing the platform device in a way that
> its name aligns with that of the driver. In such a scenario, when the driver
> is probed, the of_match_device function will return null. You can verify this
> functionality by reviewing the following function:
>
> static int platform_match(struct device *dev, struct device_driver *drv)
This particular device is found in OF-based systems only, and only
instantiated through DT. You can create a platform_device manually that
may match this driver, but that would be a made-up situation, not
something that can happen in practice.
--
Regards,
Laurent Pinchart
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: [PATCH] drm/bridge: imx: fix potential NULL pointer dereference in imx8qxp_ldb_parse_dt_companion()
2023-08-28 18:37 ` Laurent Pinchart
@ 2023-08-29 2:28 ` Ying Liu
0 siblings, 0 replies; 5+ messages in thread
From: Ying Liu @ 2023-08-29 2:28 UTC (permalink / raw)
To: Laurent Pinchart, Zhang Shurong
Cc: andrzej.hajda@intel.com, neil.armstrong@linaro.org,
rfoss@kernel.org, jonas@kwiboo.se, jernej.skrabec@gmail.com,
airlied@gmail.com, daniel@ffwll.ch, shawnguo@kernel.org,
s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com,
dl-linux-imx, dri-devel@lists.freedesktop.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
On Tuesday, August 29, 2023 2:38 AM Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote:
> On Tue, Aug 29, 2023 at 02:01:25AM +0800, Zhang Shurong wrote:
> > 在 2023年8月29日星期二 CST 上午1:28:22，Laurent Pinchart 写道：
> > > Hi Zhang,
> > >
> > > Thank you for the patch.
> > >
> > > On Tue, Aug 29, 2023 at 12:55:01AM +0800, Zhang Shurong wrote:
> > > > of_match_device() may fail and returns a NULL pointer.
> > >
> > > How can it return a NULL pointer here ?
> > >
> > > > Fix this by checking the return value of of_match_device().
> > > >
> > > > Fixes: 3818715f62b4 ("drm/bridge: imx: Add LDB support for i.MX8qxp")
> > > > Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
> > > > ---
> > > >
> > > > drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c | 2 ++
> > > > 1 file changed, 2 insertions(+)
> > > >
> > > > diff --git a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> > > > b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c index
> > > > 7984da9c0a35..d272f35c8eac 100644
> > > > --- a/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> > > > +++ b/drivers/gpu/drm/bridge/imx/imx8qxp-ldb.c
> > > > @@ -488,6 +488,8 @@ static int
> imx8qxp_ldb_parse_dt_companion(struct imx8qxp_ldb *imx8qxp_ldb)
> > > > * string.
> > > > */
> > > > match = of_match_device(dev->driver->of_match_table, dev);
> > > > + if (!match)
> > > > + return -ENODEV;
> > > > if (!of_device_is_compatible(companion, match->compatible)) {
> > > > DRM_DEV_ERROR(dev, "companion LDB is incompatible\n");
> > > > ret = -ENXIO;
> >
> > I think we can make it happen by designing the platform device in a way
> that
> > its name aligns with that of the driver. In such a scenario, when the driver
> > is probed, the of_match_device function will return null. You can verify this
> > functionality by reviewing the following function:
> >
> > static int platform_match(struct device *dev, struct device_driver *drv)
>
> This particular device is found in OF-based systems only, and only
> instantiated through DT. You can create a platform_device manually that
> may match this driver, but that would be a made-up situation, not
> something that can happen in practice.
>
I agree with Laurent.
Regards,
Liu Ying
_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 5+ messages in thread
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2023-08-28 16:55 [PATCH] drm/bridge: imx: fix potential NULL pointer dereference in imx8qxp_ldb_parse_dt_companion() Zhang Shurong
2023-08-28 17:28 ` Laurent Pinchart
2023-08-28 18:01 ` Zhang Shurong
2023-08-28 18:37 ` Laurent Pinchart
2023-08-29 2:28 ` Ying Liu
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