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* [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference
@ 2022-01-21 13:12 ` Alexander Stein
  0 siblings, 0 replies; 8+ messages in thread
From: Alexander Stein @ 2022-01-21 13:12 UTC (permalink / raw)
  To: Marek Vasut, Stefan Agner, David Airlie, Daniel Vetter,
	Shawn Guo, Sascha Hauer, Fabio Estevam
  Cc: Alexander Stein, dri-devel, linux-arm-kernel

Do not deference the NULL pointer if the bridge does not return a
bridge state. Assume a fixed format instead.

Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest bridge if present")
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
---
This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached
to it. atomic_get_input_bus_fmts is only implemented for the
lvds-decoder case.

 drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
index 0655582ae8ed..4cfb6c001679 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
@@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
 		bridge_state =
 			drm_atomic_get_new_bridge_state(state,
 							mxsfb->bridge);
-		bus_format = bridge_state->input_bus_cfg.format;
+		if (!bridge_state)
+			bus_format = MEDIA_BUS_FMT_FIXED;
+		else
+			bus_format = bridge_state->input_bus_cfg.format;
+
 		if (bus_format == MEDIA_BUS_FMT_FIXED) {
 			dev_warn_once(drm->dev,
 				      "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 8+ messages in thread

* [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference
@ 2022-01-21 13:12 ` Alexander Stein
  0 siblings, 0 replies; 8+ messages in thread
From: Alexander Stein @ 2022-01-21 13:12 UTC (permalink / raw)
  To: Marek Vasut, Stefan Agner, David Airlie, Daniel Vetter,
	Shawn Guo, Sascha Hauer, Fabio Estevam
  Cc: Alexander Stein, linux-arm-kernel, dri-devel

Do not deference the NULL pointer if the bridge does not return a
bridge state. Assume a fixed format instead.

Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest bridge if present")
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
---
This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached
to it. atomic_get_input_bus_fmts is only implemented for the
lvds-decoder case.

 drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
index 0655582ae8ed..4cfb6c001679 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
@@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
 		bridge_state =
 			drm_atomic_get_new_bridge_state(state,
 							mxsfb->bridge);
-		bus_format = bridge_state->input_bus_cfg.format;
+		if (!bridge_state)
+			bus_format = MEDIA_BUS_FMT_FIXED;
+		else
+			bus_format = bridge_state->input_bus_cfg.format;
+
 		if (bus_format == MEDIA_BUS_FMT_FIXED) {
 			dev_warn_once(drm->dev,
 				      "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
-- 
2.25.1


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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 8+ messages in thread

* Re: [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference
  2022-01-21 13:12 ` Alexander Stein
@ 2022-01-21 13:14   ` Marek Vasut
  -1 siblings, 0 replies; 8+ messages in thread
From: Marek Vasut @ 2022-01-21 13:14 UTC (permalink / raw)
  To: Alexander Stein, Stefan Agner, David Airlie, Daniel Vetter,
	Shawn Guo, Sascha Hauer, Fabio Estevam, Laurent Pinchart
  Cc: dri-devel, linux-arm-kernel

On 1/21/22 14:12, Alexander Stein wrote:
> Do not deference the NULL pointer if the bridge does not return a
> bridge state. Assume a fixed format instead.
> 
> Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest bridge if present")
> Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> ---
> This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached
> to it. atomic_get_input_bus_fmts is only implemented for the
> lvds-decoder case.
> 
>   drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> index 0655582ae8ed..4cfb6c001679 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> @@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
>   		bridge_state =
>   			drm_atomic_get_new_bridge_state(state,
>   							mxsfb->bridge);
> -		bus_format = bridge_state->input_bus_cfg.format;
> +		if (!bridge_state)
> +			bus_format = MEDIA_BUS_FMT_FIXED;
> +		else
> +			bus_format = bridge_state->input_bus_cfg.format;
> +
>   		if (bus_format == MEDIA_BUS_FMT_FIXED) {
>   			dev_warn_once(drm->dev,
>   				      "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"


Shouldn't this be fixed on the bridge driver side instead ?

Which bridge driver do you use ?

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference
@ 2022-01-21 13:14   ` Marek Vasut
  0 siblings, 0 replies; 8+ messages in thread
From: Marek Vasut @ 2022-01-21 13:14 UTC (permalink / raw)
  To: Alexander Stein, Stefan Agner, David Airlie, Daniel Vetter,
	Shawn Guo, Sascha Hauer, Fabio Estevam, Laurent Pinchart
  Cc: linux-arm-kernel, dri-devel

On 1/21/22 14:12, Alexander Stein wrote:
> Do not deference the NULL pointer if the bridge does not return a
> bridge state. Assume a fixed format instead.
> 
> Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest bridge if present")
> Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> ---
> This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached
> to it. atomic_get_input_bus_fmts is only implemented for the
> lvds-decoder case.
> 
>   drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> index 0655582ae8ed..4cfb6c001679 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> @@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
>   		bridge_state =
>   			drm_atomic_get_new_bridge_state(state,
>   							mxsfb->bridge);
> -		bus_format = bridge_state->input_bus_cfg.format;
> +		if (!bridge_state)
> +			bus_format = MEDIA_BUS_FMT_FIXED;
> +		else
> +			bus_format = bridge_state->input_bus_cfg.format;
> +
>   		if (bus_format == MEDIA_BUS_FMT_FIXED) {
>   			dev_warn_once(drm->dev,
>   				      "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"


Shouldn't this be fixed on the bridge driver side instead ?

Which bridge driver do you use ?

_______________________________________________
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: (EXT) Re: [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference
  2022-01-21 13:14   ` Marek Vasut
@ 2022-01-21 13:24     ` Alexander Stein
  -1 siblings, 0 replies; 8+ messages in thread
From: Alexander Stein @ 2022-01-21 13:24 UTC (permalink / raw)
  To: Stefan Agner, David Airlie, Daniel Vetter, Shawn Guo,
	Sascha Hauer, Fabio Estevam, Laurent Pinchart, Marek Vasut
  Cc: dri-devel, linux-arm-kernel

Am Freitag, 21. Januar 2022, 14:14:01 CET schrieb Marek Vasut:
> On 1/21/22 14:12, Alexander Stein wrote:
> > Do not deference the NULL pointer if the bridge does not return a
> > bridge state. Assume a fixed format instead.
> > 
> > Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest
> > bridge if present") Signed-off-by: Alexander Stein
> > <alexander.stein@ew.tq-group.com>
> > ---
> > This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached
> > to it. atomic_get_input_bus_fmts is only implemented for the
> > lvds-decoder case.
> > 
> >   drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
> >   1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > b/drivers/gpu/drm/mxsfb/mxsfb_kms.c index 0655582ae8ed..4cfb6c001679
> > 100644
> > --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > @@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc
> > *crtc,> 
> >   		bridge_state =
> >   		
> >   			drm_atomic_get_new_bridge_state(state,
> >   			
> >   							
mxsfb->bridge);
> > 
> > -		bus_format = bridge_state->input_bus_cfg.format;
> > +		if (!bridge_state)
> > +			bus_format = MEDIA_BUS_FMT_FIXED;
> > +		else
> > +			bus_format = bridge_state-
>input_bus_cfg.format;
> > +
> > 
> >   		if (bus_format == MEDIA_BUS_FMT_FIXED) {
> >   		
> >   			dev_warn_once(drm->dev,
> >   			
> >   				      "Bridge does not provide bus 
format, assuming
> >   				      MEDIA_BUS_FMT_RGB888_1X24.
\n"
> 
> Shouldn't this be fixed on the bridge driver side instead ?
> 
> Which bridge driver do you use ?

It's drivers/gpu/drm/bridge/lvds-codec.c. I thought naming the compatibles 
would suffice. I consider a patch for the bridge driver as a separate issue, 
hence the warning from mxsfb. Although I'm unsure how/what to implement. 
Similar to the encode case where the bus format is specified in DT? 

Anyway, mxsfb should not never dereference the NULL pointer which 
drm_atomic_get_new_bridge_state is allowed to return.

Best regards,
Alexander





^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: (EXT) Re: [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference
@ 2022-01-21 13:24     ` Alexander Stein
  0 siblings, 0 replies; 8+ messages in thread
From: Alexander Stein @ 2022-01-21 13:24 UTC (permalink / raw)
  To: Stefan Agner, David Airlie, Daniel Vetter, Shawn Guo,
	Sascha Hauer, Fabio Estevam, Laurent Pinchart, Marek Vasut
  Cc: linux-arm-kernel, dri-devel

Am Freitag, 21. Januar 2022, 14:14:01 CET schrieb Marek Vasut:
> On 1/21/22 14:12, Alexander Stein wrote:
> > Do not deference the NULL pointer if the bridge does not return a
> > bridge state. Assume a fixed format instead.
> > 
> > Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest
> > bridge if present") Signed-off-by: Alexander Stein
> > <alexander.stein@ew.tq-group.com>
> > ---
> > This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached
> > to it. atomic_get_input_bus_fmts is only implemented for the
> > lvds-decoder case.
> > 
> >   drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
> >   1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > b/drivers/gpu/drm/mxsfb/mxsfb_kms.c index 0655582ae8ed..4cfb6c001679
> > 100644
> > --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > @@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc
> > *crtc,> 
> >   		bridge_state =
> >   		
> >   			drm_atomic_get_new_bridge_state(state,
> >   			
> >   							
mxsfb->bridge);
> > 
> > -		bus_format = bridge_state->input_bus_cfg.format;
> > +		if (!bridge_state)
> > +			bus_format = MEDIA_BUS_FMT_FIXED;
> > +		else
> > +			bus_format = bridge_state-
>input_bus_cfg.format;
> > +
> > 
> >   		if (bus_format == MEDIA_BUS_FMT_FIXED) {
> >   		
> >   			dev_warn_once(drm->dev,
> >   			
> >   				      "Bridge does not provide bus 
format, assuming
> >   				      MEDIA_BUS_FMT_RGB888_1X24.
\n"
> 
> Shouldn't this be fixed on the bridge driver side instead ?
> 
> Which bridge driver do you use ?

It's drivers/gpu/drm/bridge/lvds-codec.c. I thought naming the compatibles 
would suffice. I consider a patch for the bridge driver as a separate issue, 
hence the warning from mxsfb. Although I'm unsure how/what to implement. 
Similar to the encode case where the bus format is specified in DT? 

Anyway, mxsfb should not never dereference the NULL pointer which 
drm_atomic_get_new_bridge_state is allowed to return.

Best regards,
Alexander





_______________________________________________
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: (EXT) Re: [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference
  2022-01-21 13:24     ` Alexander Stein
@ 2022-01-21 13:28       ` Marek Vasut
  -1 siblings, 0 replies; 8+ messages in thread
From: Marek Vasut @ 2022-01-21 13:28 UTC (permalink / raw)
  To: Alexander Stein, Stefan Agner, David Airlie, Daniel Vetter,
	Shawn Guo, Sascha Hauer, Fabio Estevam, Laurent Pinchart
  Cc: dri-devel, linux-arm-kernel

On 1/21/22 14:24, Alexander Stein wrote:
> Am Freitag, 21. Januar 2022, 14:14:01 CET schrieb Marek Vasut:
>> On 1/21/22 14:12, Alexander Stein wrote:
>>> Do not deference the NULL pointer if the bridge does not return a
>>> bridge state. Assume a fixed format instead.
>>>
>>> Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest
>>> bridge if present") Signed-off-by: Alexander Stein
>>> <alexander.stein@ew.tq-group.com>
>>> ---
>>> This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached
>>> to it. atomic_get_input_bus_fmts is only implemented for the
>>> lvds-decoder case.
>>>
>>>    drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
>>>    1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
>>> b/drivers/gpu/drm/mxsfb/mxsfb_kms.c index 0655582ae8ed..4cfb6c001679
>>> 100644
>>> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
>>> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
>>> @@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc
>>> *crtc,>
>>>    		bridge_state =
>>>    		
>>>    			drm_atomic_get_new_bridge_state(state,
>>>    			
>>>    							
> mxsfb->bridge);
>>>
>>> -		bus_format = bridge_state->input_bus_cfg.format;
>>> +		if (!bridge_state)
>>> +			bus_format = MEDIA_BUS_FMT_FIXED;
>>> +		else
>>> +			bus_format = bridge_state-
>> input_bus_cfg.format;
>>> +
>>>
>>>    		if (bus_format == MEDIA_BUS_FMT_FIXED) {
>>>    		
>>>    			dev_warn_once(drm->dev,
>>>    			
>>>    				      "Bridge does not provide bus
> format, assuming
>>>    				      MEDIA_BUS_FMT_RGB888_1X24.
> \n"
>>
>> Shouldn't this be fixed on the bridge driver side instead ?
>>
>> Which bridge driver do you use ?
> 
> It's drivers/gpu/drm/bridge/lvds-codec.c. I thought naming the compatibles
> would suffice. I consider a patch for the bridge driver as a separate issue,
> hence the warning from mxsfb. Although I'm unsure how/what to implement.
> Similar to the encode case where the bus format is specified in DT?

I'm sorry, I missed the lvds-codec part. Laurent is already on CC.

> Anyway, mxsfb should not never dereference the NULL pointer which
> drm_atomic_get_new_bridge_state is allowed to return.

That line ^ should be in the commit message.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: (EXT) Re: [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference
@ 2022-01-21 13:28       ` Marek Vasut
  0 siblings, 0 replies; 8+ messages in thread
From: Marek Vasut @ 2022-01-21 13:28 UTC (permalink / raw)
  To: Alexander Stein, Stefan Agner, David Airlie, Daniel Vetter,
	Shawn Guo, Sascha Hauer, Fabio Estevam, Laurent Pinchart
  Cc: linux-arm-kernel, dri-devel

On 1/21/22 14:24, Alexander Stein wrote:
> Am Freitag, 21. Januar 2022, 14:14:01 CET schrieb Marek Vasut:
>> On 1/21/22 14:12, Alexander Stein wrote:
>>> Do not deference the NULL pointer if the bridge does not return a
>>> bridge state. Assume a fixed format instead.
>>>
>>> Fixes: commit b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest
>>> bridge if present") Signed-off-by: Alexander Stein
>>> <alexander.stein@ew.tq-group.com>
>>> ---
>>> This can happen if a "ti,sn75lvds83", "lvds-encoder" bridge is attached
>>> to it. atomic_get_input_bus_fmts is only implemented for the
>>> lvds-decoder case.
>>>
>>>    drivers/gpu/drm/mxsfb/mxsfb_kms.c | 6 +++++-
>>>    1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
>>> b/drivers/gpu/drm/mxsfb/mxsfb_kms.c index 0655582ae8ed..4cfb6c001679
>>> 100644
>>> --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
>>> +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
>>> @@ -361,7 +361,11 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc
>>> *crtc,>
>>>    		bridge_state =
>>>    		
>>>    			drm_atomic_get_new_bridge_state(state,
>>>    			
>>>    							
> mxsfb->bridge);
>>>
>>> -		bus_format = bridge_state->input_bus_cfg.format;
>>> +		if (!bridge_state)
>>> +			bus_format = MEDIA_BUS_FMT_FIXED;
>>> +		else
>>> +			bus_format = bridge_state-
>> input_bus_cfg.format;
>>> +
>>>
>>>    		if (bus_format == MEDIA_BUS_FMT_FIXED) {
>>>    		
>>>    			dev_warn_once(drm->dev,
>>>    			
>>>    				      "Bridge does not provide bus
> format, assuming
>>>    				      MEDIA_BUS_FMT_RGB888_1X24.
> \n"
>>
>> Shouldn't this be fixed on the bridge driver side instead ?
>>
>> Which bridge driver do you use ?
> 
> It's drivers/gpu/drm/bridge/lvds-codec.c. I thought naming the compatibles
> would suffice. I consider a patch for the bridge driver as a separate issue,
> hence the warning from mxsfb. Although I'm unsure how/what to implement.
> Similar to the encode case where the bus format is specified in DT?

I'm sorry, I missed the lvds-codec part. Laurent is already on CC.

> Anyway, mxsfb should not never dereference the NULL pointer which
> drm_atomic_get_new_bridge_state is allowed to return.

That line ^ should be in the commit message.

_______________________________________________
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

end of thread, other threads:[~2022-01-21 13:30 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-01-21 13:12 [PATCH 1/1] drm: mxsfb: Fix NULL pointer dereference Alexander Stein
2022-01-21 13:12 ` Alexander Stein
2022-01-21 13:14 ` Marek Vasut
2022-01-21 13:14   ` Marek Vasut
2022-01-21 13:24   ` (EXT) " Alexander Stein
2022-01-21 13:24     ` Alexander Stein
2022-01-21 13:28     ` Marek Vasut
2022-01-21 13:28       ` Marek Vasut

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