* [PATCH v2] drm/meson: fix potential NULL pointer exception in meson_drv_unbind()
@ 2021-06-18 5:28 ` Jiajun Cao
0 siblings, 0 replies; 8+ messages in thread
From: Jiajun Cao @ 2021-06-18 5:28 UTC (permalink / raw)
Cc: yuanxzhang, Jiajun Cao, Xin Tan, Neil Armstrong, David Airlie,
Daniel Vetter, Kevin Hilman, Jerome Brunet, Martin Blumenstingl,
dri-devel, linux-amlogic, linux-arm-kernel, linux-kernel
Fix a potential NULL pointer exception when meson_drv_unbind()
attempts to operate on the driver_data priv which may be NULL.
Add a null pointer check on the priv struct to avoid the NULL
pointer dereference after calling dev_get_drvdata(), just like
the null pointer checks done on the struct priv in the function
meson_drv_shutdown(), meson_drv_pm_suspend() and meson_drv_pm_resume().
Signed-off-by: Jiajun Cao <jjcao20@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
drivers/gpu/drm/meson/meson_drv.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 07fcd12dca16..f544fba8c44e 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -380,7 +380,10 @@ static int meson_drv_bind(struct device *dev)
static void meson_drv_unbind(struct device *dev)
{
struct meson_drm *priv = dev_get_drvdata(dev);
- struct drm_device *drm = priv->drm;
+ struct drm_device *drm;
+
+ if (!priv)
+ return;
if (priv->canvas) {
meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
@@ -389,6 +392,7 @@ static void meson_drv_unbind(struct device *dev)
meson_canvas_free(priv->canvas, priv->canvas_id_vd1_2);
}
+ drm = priv->drm;
drm_dev_unregister(drm);
drm_kms_helper_poll_fini(drm);
drm_atomic_helper_shutdown(drm);
--
2.17.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2] drm/meson: fix potential NULL pointer exception in meson_drv_unbind()
@ 2021-06-18 5:28 ` Jiajun Cao
0 siblings, 0 replies; 8+ messages in thread
From: Jiajun Cao @ 2021-06-18 5:28 UTC (permalink / raw)
Cc: yuanxzhang, Jiajun Cao, Xin Tan, Neil Armstrong, David Airlie,
Daniel Vetter, Kevin Hilman, Jerome Brunet, Martin Blumenstingl,
dri-devel, linux-amlogic, linux-arm-kernel, linux-kernel
Fix a potential NULL pointer exception when meson_drv_unbind()
attempts to operate on the driver_data priv which may be NULL.
Add a null pointer check on the priv struct to avoid the NULL
pointer dereference after calling dev_get_drvdata(), just like
the null pointer checks done on the struct priv in the function
meson_drv_shutdown(), meson_drv_pm_suspend() and meson_drv_pm_resume().
Signed-off-by: Jiajun Cao <jjcao20@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
drivers/gpu/drm/meson/meson_drv.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 07fcd12dca16..f544fba8c44e 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -380,7 +380,10 @@ static int meson_drv_bind(struct device *dev)
static void meson_drv_unbind(struct device *dev)
{
struct meson_drm *priv = dev_get_drvdata(dev);
- struct drm_device *drm = priv->drm;
+ struct drm_device *drm;
+
+ if (!priv)
+ return;
if (priv->canvas) {
meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
@@ -389,6 +392,7 @@ static void meson_drv_unbind(struct device *dev)
meson_canvas_free(priv->canvas, priv->canvas_id_vd1_2);
}
+ drm = priv->drm;
drm_dev_unregister(drm);
drm_kms_helper_poll_fini(drm);
drm_atomic_helper_shutdown(drm);
--
2.17.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2] drm/meson: fix potential NULL pointer exception in meson_drv_unbind()
@ 2021-06-18 5:28 ` Jiajun Cao
0 siblings, 0 replies; 8+ messages in thread
From: Jiajun Cao @ 2021-06-18 5:28 UTC (permalink / raw)
Cc: Xin Tan, Neil Armstrong, David Airlie, Kevin Hilman, yuanxzhang,
linux-kernel, dri-devel, Jiajun Cao, Martin Blumenstingl,
linux-amlogic, linux-arm-kernel, Jerome Brunet
Fix a potential NULL pointer exception when meson_drv_unbind()
attempts to operate on the driver_data priv which may be NULL.
Add a null pointer check on the priv struct to avoid the NULL
pointer dereference after calling dev_get_drvdata(), just like
the null pointer checks done on the struct priv in the function
meson_drv_shutdown(), meson_drv_pm_suspend() and meson_drv_pm_resume().
Signed-off-by: Jiajun Cao <jjcao20@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
drivers/gpu/drm/meson/meson_drv.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 07fcd12dca16..f544fba8c44e 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -380,7 +380,10 @@ static int meson_drv_bind(struct device *dev)
static void meson_drv_unbind(struct device *dev)
{
struct meson_drm *priv = dev_get_drvdata(dev);
- struct drm_device *drm = priv->drm;
+ struct drm_device *drm;
+
+ if (!priv)
+ return;
if (priv->canvas) {
meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
@@ -389,6 +392,7 @@ static void meson_drv_unbind(struct device *dev)
meson_canvas_free(priv->canvas, priv->canvas_id_vd1_2);
}
+ drm = priv->drm;
drm_dev_unregister(drm);
drm_kms_helper_poll_fini(drm);
drm_atomic_helper_shutdown(drm);
--
2.17.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2] drm/meson: fix potential NULL pointer exception in meson_drv_unbind()
@ 2021-06-18 5:28 ` Jiajun Cao
0 siblings, 0 replies; 8+ messages in thread
From: Jiajun Cao @ 2021-06-18 5:28 UTC (permalink / raw)
Cc: yuanxzhang, Jiajun Cao, Xin Tan, Neil Armstrong, David Airlie,
Daniel Vetter, Kevin Hilman, Jerome Brunet, Martin Blumenstingl,
dri-devel, linux-amlogic, linux-arm-kernel, linux-kernel
Fix a potential NULL pointer exception when meson_drv_unbind()
attempts to operate on the driver_data priv which may be NULL.
Add a null pointer check on the priv struct to avoid the NULL
pointer dereference after calling dev_get_drvdata(), just like
the null pointer checks done on the struct priv in the function
meson_drv_shutdown(), meson_drv_pm_suspend() and meson_drv_pm_resume().
Signed-off-by: Jiajun Cao <jjcao20@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
drivers/gpu/drm/meson/meson_drv.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 07fcd12dca16..f544fba8c44e 100644
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -380,7 +380,10 @@ static int meson_drv_bind(struct device *dev)
static void meson_drv_unbind(struct device *dev)
{
struct meson_drm *priv = dev_get_drvdata(dev);
- struct drm_device *drm = priv->drm;
+ struct drm_device *drm;
+
+ if (!priv)
+ return;
if (priv->canvas) {
meson_canvas_free(priv->canvas, priv->canvas_id_osd1);
@@ -389,6 +392,7 @@ static void meson_drv_unbind(struct device *dev)
meson_canvas_free(priv->canvas, priv->canvas_id_vd1_2);
}
+ drm = priv->drm;
drm_dev_unregister(drm);
drm_kms_helper_poll_fini(drm);
drm_atomic_helper_shutdown(drm);
--
2.17.1
_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2] drm/meson: fix potential NULL pointer exception in meson_drv_unbind()
2021-06-18 5:28 ` Jiajun Cao
(?)
(?)
@ 2021-07-01 21:34 ` Martin Blumenstingl
-1 siblings, 0 replies; 8+ messages in thread
From: Martin Blumenstingl @ 2021-07-01 21:34 UTC (permalink / raw)
To: Jiajun Cao
Cc: yuanxzhang, Xin Tan, Neil Armstrong, David Airlie, Daniel Vetter,
Kevin Hilman, Jerome Brunet, dri-devel, linux-amlogic,
linux-arm-kernel, linux-kernel
Hello,
first of all: thanks for your patch and sorry for being late with my
review question.
On Fri, Jun 18, 2021 at 7:28 AM Jiajun Cao <jjcao20@fudan.edu.cn> wrote:
>
> Fix a potential NULL pointer exception when meson_drv_unbind()
> attempts to operate on the driver_data priv which may be NULL.
> Add a null pointer check on the priv struct to avoid the NULL
> pointer dereference after calling dev_get_drvdata(), just like
> the null pointer checks done on the struct priv in the function
> meson_drv_shutdown(), meson_drv_pm_suspend() and meson_drv_pm_resume().
I am trying to review Amlogic Meson related patches in the DRM
subsystem so I can help Neil with this.
However, I am still new to this so please help me educate on this topic.
[...]
> static void meson_drv_unbind(struct device *dev)
> {
> struct meson_drm *priv = dev_get_drvdata(dev);
> - struct drm_device *drm = priv->drm;
> + struct drm_device *drm;
> +
> + if (!priv)
> + return;
My understanding of the component framework is that meson_drv_unbind()
is only called if previously meson_drv_bind() was called (and did not
return any error).
This is different from meson_drv_shutdown() (for example) because that
can be called if meson_drv_probe() returns 0 (success) in case the
"count" variable was 0 (then the probe function does nothing).
As I mentioned before: I am still learning about the DRM subsystem in
the Linux kernel.
So it would be great if you could help me understand for which
scenarios this newly added if-condition is needed.
Thank you!
Best regards,
Martin
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] drm/meson: fix potential NULL pointer exception in meson_drv_unbind()
@ 2021-07-01 21:34 ` Martin Blumenstingl
0 siblings, 0 replies; 8+ messages in thread
From: Martin Blumenstingl @ 2021-07-01 21:34 UTC (permalink / raw)
To: Jiajun Cao
Cc: yuanxzhang, Xin Tan, Neil Armstrong, David Airlie, Daniel Vetter,
Kevin Hilman, Jerome Brunet, dri-devel, linux-amlogic,
linux-arm-kernel, linux-kernel
Hello,
first of all: thanks for your patch and sorry for being late with my
review question.
On Fri, Jun 18, 2021 at 7:28 AM Jiajun Cao <jjcao20@fudan.edu.cn> wrote:
>
> Fix a potential NULL pointer exception when meson_drv_unbind()
> attempts to operate on the driver_data priv which may be NULL.
> Add a null pointer check on the priv struct to avoid the NULL
> pointer dereference after calling dev_get_drvdata(), just like
> the null pointer checks done on the struct priv in the function
> meson_drv_shutdown(), meson_drv_pm_suspend() and meson_drv_pm_resume().
I am trying to review Amlogic Meson related patches in the DRM
subsystem so I can help Neil with this.
However, I am still new to this so please help me educate on this topic.
[...]
> static void meson_drv_unbind(struct device *dev)
> {
> struct meson_drm *priv = dev_get_drvdata(dev);
> - struct drm_device *drm = priv->drm;
> + struct drm_device *drm;
> +
> + if (!priv)
> + return;
My understanding of the component framework is that meson_drv_unbind()
is only called if previously meson_drv_bind() was called (and did not
return any error).
This is different from meson_drv_shutdown() (for example) because that
can be called if meson_drv_probe() returns 0 (success) in case the
"count" variable was 0 (then the probe function does nothing).
As I mentioned before: I am still learning about the DRM subsystem in
the Linux kernel.
So it would be great if you could help me understand for which
scenarios this newly added if-condition is needed.
Thank you!
Best regards,
Martin
_______________________________________________
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] 8+ messages in thread
* Re: [PATCH v2] drm/meson: fix potential NULL pointer exception in meson_drv_unbind()
@ 2021-07-01 21:34 ` Martin Blumenstingl
0 siblings, 0 replies; 8+ messages in thread
From: Martin Blumenstingl @ 2021-07-01 21:34 UTC (permalink / raw)
To: Jiajun Cao
Cc: Xin Tan, Neil Armstrong, David Airlie, Kevin Hilman, yuanxzhang,
linux-kernel, dri-devel, linux-amlogic, linux-arm-kernel,
Jerome Brunet
Hello,
first of all: thanks for your patch and sorry for being late with my
review question.
On Fri, Jun 18, 2021 at 7:28 AM Jiajun Cao <jjcao20@fudan.edu.cn> wrote:
>
> Fix a potential NULL pointer exception when meson_drv_unbind()
> attempts to operate on the driver_data priv which may be NULL.
> Add a null pointer check on the priv struct to avoid the NULL
> pointer dereference after calling dev_get_drvdata(), just like
> the null pointer checks done on the struct priv in the function
> meson_drv_shutdown(), meson_drv_pm_suspend() and meson_drv_pm_resume().
I am trying to review Amlogic Meson related patches in the DRM
subsystem so I can help Neil with this.
However, I am still new to this so please help me educate on this topic.
[...]
> static void meson_drv_unbind(struct device *dev)
> {
> struct meson_drm *priv = dev_get_drvdata(dev);
> - struct drm_device *drm = priv->drm;
> + struct drm_device *drm;
> +
> + if (!priv)
> + return;
My understanding of the component framework is that meson_drv_unbind()
is only called if previously meson_drv_bind() was called (and did not
return any error).
This is different from meson_drv_shutdown() (for example) because that
can be called if meson_drv_probe() returns 0 (success) in case the
"count" variable was 0 (then the probe function does nothing).
As I mentioned before: I am still learning about the DRM subsystem in
the Linux kernel.
So it would be great if you could help me understand for which
scenarios this newly added if-condition is needed.
Thank you!
Best regards,
Martin
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] drm/meson: fix potential NULL pointer exception in meson_drv_unbind()
@ 2021-07-01 21:34 ` Martin Blumenstingl
0 siblings, 0 replies; 8+ messages in thread
From: Martin Blumenstingl @ 2021-07-01 21:34 UTC (permalink / raw)
To: Jiajun Cao
Cc: yuanxzhang, Xin Tan, Neil Armstrong, David Airlie, Daniel Vetter,
Kevin Hilman, Jerome Brunet, dri-devel, linux-amlogic,
linux-arm-kernel, linux-kernel
Hello,
first of all: thanks for your patch and sorry for being late with my
review question.
On Fri, Jun 18, 2021 at 7:28 AM Jiajun Cao <jjcao20@fudan.edu.cn> wrote:
>
> Fix a potential NULL pointer exception when meson_drv_unbind()
> attempts to operate on the driver_data priv which may be NULL.
> Add a null pointer check on the priv struct to avoid the NULL
> pointer dereference after calling dev_get_drvdata(), just like
> the null pointer checks done on the struct priv in the function
> meson_drv_shutdown(), meson_drv_pm_suspend() and meson_drv_pm_resume().
I am trying to review Amlogic Meson related patches in the DRM
subsystem so I can help Neil with this.
However, I am still new to this so please help me educate on this topic.
[...]
> static void meson_drv_unbind(struct device *dev)
> {
> struct meson_drm *priv = dev_get_drvdata(dev);
> - struct drm_device *drm = priv->drm;
> + struct drm_device *drm;
> +
> + if (!priv)
> + return;
My understanding of the component framework is that meson_drv_unbind()
is only called if previously meson_drv_bind() was called (and did not
return any error).
This is different from meson_drv_shutdown() (for example) because that
can be called if meson_drv_probe() returns 0 (success) in case the
"count" variable was 0 (then the probe function does nothing).
As I mentioned before: I am still learning about the DRM subsystem in
the Linux kernel.
So it would be great if you could help me understand for which
scenarios this newly added if-condition is needed.
Thank you!
Best regards,
Martin
_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2021-07-01 21:36 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-18 5:28 [PATCH v2] drm/meson: fix potential NULL pointer exception in meson_drv_unbind() Jiajun Cao
2021-06-18 5:28 ` Jiajun Cao
2021-06-18 5:28 ` Jiajun Cao
2021-06-18 5:28 ` Jiajun Cao
2021-07-01 21:34 ` Martin Blumenstingl
2021-07-01 21:34 ` Martin Blumenstingl
2021-07-01 21:34 ` Martin Blumenstingl
2021-07-01 21:34 ` Martin Blumenstingl
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