[PATCH 10/13] media: adv7604 prevent underflow condition when reporting colorspace

Mauro Carvalho Chehab posted 13 patches 1 month, 1 week ago
There is a newer version of this series
[PATCH 10/13] media: adv7604 prevent underflow condition when reporting colorspace
Posted by Mauro Carvalho Chehab 1 month, 1 week ago
Currently, adv76xx_log_status() reads some date using
io_read() which may return negative values. The current logi
doesn't check such errors, causing colorspace to be reported
on a wrong way at adv76xx_log_status().

If I/O error happens there, print a different message, instead
of reporting bogus messages to userspace.

Fixes: 54450f591c99 ("[media] adv7604: driver for the Analog Devices ADV7604 video decoder")
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 drivers/media/i2c/adv7604.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
index 48230d5109f0..272945a878b3 100644
--- a/drivers/media/i2c/adv7604.c
+++ b/drivers/media/i2c/adv7604.c
@@ -2519,10 +2519,10 @@ static int adv76xx_log_status(struct v4l2_subdev *sd)
 	const struct adv76xx_chip_info *info = state->info;
 	struct v4l2_dv_timings timings;
 	struct stdi_readback stdi;
-	u8 reg_io_0x02 = io_read(sd, 0x02);
+	int ret;
+	u8 reg_io_0x02;
 	u8 edid_enabled;
 	u8 cable_det;
-
 	static const char * const csc_coeff_sel_rb[16] = {
 		"bypassed", "YPbPr601 -> RGB", "reserved", "YPbPr709 -> RGB",
 		"reserved", "RGB -> YPbPr601", "reserved", "RGB -> YPbPr709",
@@ -2621,13 +2621,21 @@ static int adv76xx_log_status(struct v4l2_subdev *sd)
 	v4l2_info(sd, "-----Color space-----\n");
 	v4l2_info(sd, "RGB quantization range ctrl: %s\n",
 			rgb_quantization_range_txt[state->rgb_quantization_range]);
-	v4l2_info(sd, "Input color space: %s\n",
-			input_color_space_txt[reg_io_0x02 >> 4]);
-	v4l2_info(sd, "Output color space: %s %s, alt-gamma %s\n",
-			(reg_io_0x02 & 0x02) ? "RGB" : "YCbCr",
-			(((reg_io_0x02 >> 2) & 0x01) ^ (reg_io_0x02 & 0x01)) ?
-				"(16-235)" : "(0-255)",
-			(reg_io_0x02 & 0x08) ? "enabled" : "disabled");
+
+	ret = io_read(sd, 0x02);
+	if (ret < 0) {
+		v4l2_info(sd, "Can't read Input/Output color space\n");
+	} else {
+		reg_io_0x02 = ret;
+
+		v4l2_info(sd, "Input color space: %s\n",
+				input_color_space_txt[reg_io_0x02 >> 4]);
+		v4l2_info(sd, "Output color space: %s %s, alt-gamma %s\n",
+				(reg_io_0x02 & 0x02) ? "RGB" : "YCbCr",
+				(((reg_io_0x02 >> 2) & 0x01) ^ (reg_io_0x02 & 0x01)) ?
+					"(16-235)" : "(0-255)",
+				(reg_io_0x02 & 0x08) ? "enabled" : "disabled");
+	}
 	v4l2_info(sd, "Color space conversion: %s\n",
 			csc_coeff_sel_rb[cp_read(sd, info->cp_csc) >> 4]);
 
-- 
2.47.0
Re: [PATCH 10/13] media: adv7604 prevent underflow condition when reporting colorspace
Posted by Hans Verkuil 1 month, 1 week ago
On 16/10/2024 12:22, Mauro Carvalho Chehab wrote:
> Currently, adv76xx_log_status() reads some date using
> io_read() which may return negative values. The current logi
> doesn't check such errors, causing colorspace to be reported
> on a wrong way at adv76xx_log_status().
> 
> If I/O error happens there, print a different message, instead
> of reporting bogus messages to userspace.
> 
> Fixes: 54450f591c99 ("[media] adv7604: driver for the Analog Devices ADV7604 video decoder")
> Cc: stable@vger.kernel.org

Not really a fix since this would just affect logging for debugging
purposes. I would personally just drop the Fixes and Cc tag.

> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>

Regards,

	Hans

> ---
>  drivers/media/i2c/adv7604.c | 26 +++++++++++++++++---------
>  1 file changed, 17 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
> index 48230d5109f0..272945a878b3 100644
> --- a/drivers/media/i2c/adv7604.c
> +++ b/drivers/media/i2c/adv7604.c
> @@ -2519,10 +2519,10 @@ static int adv76xx_log_status(struct v4l2_subdev *sd)
>  	const struct adv76xx_chip_info *info = state->info;
>  	struct v4l2_dv_timings timings;
>  	struct stdi_readback stdi;
> -	u8 reg_io_0x02 = io_read(sd, 0x02);
> +	int ret;
> +	u8 reg_io_0x02;
>  	u8 edid_enabled;
>  	u8 cable_det;
> -
>  	static const char * const csc_coeff_sel_rb[16] = {
>  		"bypassed", "YPbPr601 -> RGB", "reserved", "YPbPr709 -> RGB",
>  		"reserved", "RGB -> YPbPr601", "reserved", "RGB -> YPbPr709",
> @@ -2621,13 +2621,21 @@ static int adv76xx_log_status(struct v4l2_subdev *sd)
>  	v4l2_info(sd, "-----Color space-----\n");
>  	v4l2_info(sd, "RGB quantization range ctrl: %s\n",
>  			rgb_quantization_range_txt[state->rgb_quantization_range]);
> -	v4l2_info(sd, "Input color space: %s\n",
> -			input_color_space_txt[reg_io_0x02 >> 4]);
> -	v4l2_info(sd, "Output color space: %s %s, alt-gamma %s\n",
> -			(reg_io_0x02 & 0x02) ? "RGB" : "YCbCr",
> -			(((reg_io_0x02 >> 2) & 0x01) ^ (reg_io_0x02 & 0x01)) ?
> -				"(16-235)" : "(0-255)",
> -			(reg_io_0x02 & 0x08) ? "enabled" : "disabled");
> +
> +	ret = io_read(sd, 0x02);
> +	if (ret < 0) {
> +		v4l2_info(sd, "Can't read Input/Output color space\n");
> +	} else {
> +		reg_io_0x02 = ret;
> +
> +		v4l2_info(sd, "Input color space: %s\n",
> +				input_color_space_txt[reg_io_0x02 >> 4]);
> +		v4l2_info(sd, "Output color space: %s %s, alt-gamma %s\n",
> +				(reg_io_0x02 & 0x02) ? "RGB" : "YCbCr",
> +				(((reg_io_0x02 >> 2) & 0x01) ^ (reg_io_0x02 & 0x01)) ?
> +					"(16-235)" : "(0-255)",
> +				(reg_io_0x02 & 0x08) ? "enabled" : "disabled");
> +	}
>  	v4l2_info(sd, "Color space conversion: %s\n",
>  			csc_coeff_sel_rb[cp_read(sd, info->cp_csc) >> 4]);
>
Re: [PATCH 10/13] media: adv7604 prevent underflow condition when reporting colorspace
Posted by Mauro Carvalho Chehab 1 month, 1 week ago
Em Wed, 16 Oct 2024 12:57:53 +0200
Hans Verkuil <hverkuil@xs4all.nl> escreveu:

> On 16/10/2024 12:22, Mauro Carvalho Chehab wrote:
> > Currently, adv76xx_log_status() reads some date using
> > io_read() which may return negative values. The current logi
> > doesn't check such errors, causing colorspace to be reported
> > on a wrong way at adv76xx_log_status().
> > 
> > If I/O error happens there, print a different message, instead
> > of reporting bogus messages to userspace.
> > 
> > Fixes: 54450f591c99 ("[media] adv7604: driver for the Analog Devices ADV7604 video decoder")
> > Cc: stable@vger.kernel.org  
> 
> Not really a fix since this would just affect logging for debugging
> purposes. I would personally just drop the Fixes and Cc tag.

The issue is on a VIDIOC_ ioctl, so part of media API. Ok, this is
used only for debugging purposes and should, instead be implemented
via debugfs, etc, but, in summary: it is what it is: part of the V4L2
uAPI.

-

Now, the question about what should have Fixes: tag and what
shouldn't is a different matter. I've saw long discussions about
that at the kernel mailing lists. In the particular case of y2038,
I'm pretty sure I saw some of them with Fixes tag on it.

> 
> > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>  
> 
> Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
> 
> Regards,
> 
> 	Hans
> 
> > ---
> >  drivers/media/i2c/adv7604.c | 26 +++++++++++++++++---------
> >  1 file changed, 17 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
> > index 48230d5109f0..272945a878b3 100644
> > --- a/drivers/media/i2c/adv7604.c
> > +++ b/drivers/media/i2c/adv7604.c
> > @@ -2519,10 +2519,10 @@ static int adv76xx_log_status(struct v4l2_subdev *sd)
> >  	const struct adv76xx_chip_info *info = state->info;
> >  	struct v4l2_dv_timings timings;
> >  	struct stdi_readback stdi;
> > -	u8 reg_io_0x02 = io_read(sd, 0x02);
> > +	int ret;
> > +	u8 reg_io_0x02;
> >  	u8 edid_enabled;
> >  	u8 cable_det;
> > -
> >  	static const char * const csc_coeff_sel_rb[16] = {
> >  		"bypassed", "YPbPr601 -> RGB", "reserved", "YPbPr709 -> RGB",
> >  		"reserved", "RGB -> YPbPr601", "reserved", "RGB -> YPbPr709",
> > @@ -2621,13 +2621,21 @@ static int adv76xx_log_status(struct v4l2_subdev *sd)
> >  	v4l2_info(sd, "-----Color space-----\n");
> >  	v4l2_info(sd, "RGB quantization range ctrl: %s\n",
> >  			rgb_quantization_range_txt[state->rgb_quantization_range]);
> > -	v4l2_info(sd, "Input color space: %s\n",
> > -			input_color_space_txt[reg_io_0x02 >> 4]);
> > -	v4l2_info(sd, "Output color space: %s %s, alt-gamma %s\n",
> > -			(reg_io_0x02 & 0x02) ? "RGB" : "YCbCr",
> > -			(((reg_io_0x02 >> 2) & 0x01) ^ (reg_io_0x02 & 0x01)) ?
> > -				"(16-235)" : "(0-255)",
> > -			(reg_io_0x02 & 0x08) ? "enabled" : "disabled");
> > +
> > +	ret = io_read(sd, 0x02);
> > +	if (ret < 0) {
> > +		v4l2_info(sd, "Can't read Input/Output color space\n");
> > +	} else {
> > +		reg_io_0x02 = ret;
> > +
> > +		v4l2_info(sd, "Input color space: %s\n",
> > +				input_color_space_txt[reg_io_0x02 >> 4]);
> > +		v4l2_info(sd, "Output color space: %s %s, alt-gamma %s\n",
> > +				(reg_io_0x02 & 0x02) ? "RGB" : "YCbCr",
> > +				(((reg_io_0x02 >> 2) & 0x01) ^ (reg_io_0x02 & 0x01)) ?
> > +					"(16-235)" : "(0-255)",
> > +				(reg_io_0x02 & 0x08) ? "enabled" : "disabled");
> > +	}
> >  	v4l2_info(sd, "Color space conversion: %s\n",
> >  			csc_coeff_sel_rb[cp_read(sd, info->cp_csc) >> 4]);
> >    
> 



Thanks,
Mauro
Re: [PATCH 10/13] media: adv7604 prevent underflow condition when reporting colorspace
Posted by Hans Verkuil 1 month, 1 week ago
On 16/10/2024 13:24, Mauro Carvalho Chehab wrote:
> Em Wed, 16 Oct 2024 12:57:53 +0200
> Hans Verkuil <hverkuil@xs4all.nl> escreveu:
> 
>> On 16/10/2024 12:22, Mauro Carvalho Chehab wrote:
>>> Currently, adv76xx_log_status() reads some date using
>>> io_read() which may return negative values. The current logi
>>> doesn't check such errors, causing colorspace to be reported
>>> on a wrong way at adv76xx_log_status().
>>>
>>> If I/O error happens there, print a different message, instead
>>> of reporting bogus messages to userspace.
>>>
>>> Fixes: 54450f591c99 ("[media] adv7604: driver for the Analog Devices ADV7604 video decoder")
>>> Cc: stable@vger.kernel.org  
>>
>> Not really a fix since this would just affect logging for debugging
>> purposes. I would personally just drop the Fixes and Cc tag.
> 
> The issue is on a VIDIOC_ ioctl, so part of media API. Ok, this is
> used only for debugging purposes and should, instead be implemented
> via debugfs, etc, but, in summary: it is what it is: part of the V4L2
> uAPI.

The ioctl, yes, but what it logs to the kernel log isn't part of the ABI.
That can change.

I think it is overkill to send this to stable for an old chip that almost
nobody uses, and that requires an i2c read to go wrong for it to produce
a wrong debug message. It seems an unnecessary waste of time.

> 
> -
> 
> Now, the question about what should have Fixes: tag and what
> shouldn't is a different matter. I've saw long discussions about
> that at the kernel mailing lists. In the particular case of y2038,
> I'm pretty sure I saw some of them with Fixes tag on it.

But patch 13/13 doesn't affect the operation either, again it is just
an incorrect log message that can only go wrong if Pulse-Eight still
sells that device in 2038 with a firmware build date >= 2038. And v6.12
is guaranteed to be EOL in 2038 :-)

Regards,

	Hans

> 
>>
>>> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>  
>>
>> Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
>>
>> Regards,
>>
>> 	Hans
>>
>>> ---
>>>  drivers/media/i2c/adv7604.c | 26 +++++++++++++++++---------
>>>  1 file changed, 17 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/media/i2c/adv7604.c b/drivers/media/i2c/adv7604.c
>>> index 48230d5109f0..272945a878b3 100644
>>> --- a/drivers/media/i2c/adv7604.c
>>> +++ b/drivers/media/i2c/adv7604.c
>>> @@ -2519,10 +2519,10 @@ static int adv76xx_log_status(struct v4l2_subdev *sd)
>>>  	const struct adv76xx_chip_info *info = state->info;
>>>  	struct v4l2_dv_timings timings;
>>>  	struct stdi_readback stdi;
>>> -	u8 reg_io_0x02 = io_read(sd, 0x02);
>>> +	int ret;
>>> +	u8 reg_io_0x02;
>>>  	u8 edid_enabled;
>>>  	u8 cable_det;
>>> -
>>>  	static const char * const csc_coeff_sel_rb[16] = {
>>>  		"bypassed", "YPbPr601 -> RGB", "reserved", "YPbPr709 -> RGB",
>>>  		"reserved", "RGB -> YPbPr601", "reserved", "RGB -> YPbPr709",
>>> @@ -2621,13 +2621,21 @@ static int adv76xx_log_status(struct v4l2_subdev *sd)
>>>  	v4l2_info(sd, "-----Color space-----\n");
>>>  	v4l2_info(sd, "RGB quantization range ctrl: %s\n",
>>>  			rgb_quantization_range_txt[state->rgb_quantization_range]);
>>> -	v4l2_info(sd, "Input color space: %s\n",
>>> -			input_color_space_txt[reg_io_0x02 >> 4]);
>>> -	v4l2_info(sd, "Output color space: %s %s, alt-gamma %s\n",
>>> -			(reg_io_0x02 & 0x02) ? "RGB" : "YCbCr",
>>> -			(((reg_io_0x02 >> 2) & 0x01) ^ (reg_io_0x02 & 0x01)) ?
>>> -				"(16-235)" : "(0-255)",
>>> -			(reg_io_0x02 & 0x08) ? "enabled" : "disabled");
>>> +
>>> +	ret = io_read(sd, 0x02);
>>> +	if (ret < 0) {
>>> +		v4l2_info(sd, "Can't read Input/Output color space\n");
>>> +	} else {
>>> +		reg_io_0x02 = ret;
>>> +
>>> +		v4l2_info(sd, "Input color space: %s\n",
>>> +				input_color_space_txt[reg_io_0x02 >> 4]);
>>> +		v4l2_info(sd, "Output color space: %s %s, alt-gamma %s\n",
>>> +				(reg_io_0x02 & 0x02) ? "RGB" : "YCbCr",
>>> +				(((reg_io_0x02 >> 2) & 0x01) ^ (reg_io_0x02 & 0x01)) ?
>>> +					"(16-235)" : "(0-255)",
>>> +				(reg_io_0x02 & 0x08) ? "enabled" : "disabled");
>>> +	}
>>>  	v4l2_info(sd, "Color space conversion: %s\n",
>>>  			csc_coeff_sel_rb[cp_read(sd, info->cp_csc) >> 4]);
>>>    
>>
> 
> 
> 
> Thanks,
> Mauro
Re: [PATCH 10/13] media: adv7604 prevent underflow condition when reporting colorspace
Posted by Mauro Carvalho Chehab 1 month, 1 week ago
Em Wed, 16 Oct 2024 13:58:48 +0200
Hans Verkuil <hverkuil@xs4all.nl> escreveu:

> On 16/10/2024 13:24, Mauro Carvalho Chehab wrote:
> > Em Wed, 16 Oct 2024 12:57:53 +0200
> > Hans Verkuil <hverkuil@xs4all.nl> escreveu:
> >   
> >> On 16/10/2024 12:22, Mauro Carvalho Chehab wrote:  
> >>> Currently, adv76xx_log_status() reads some date using
> >>> io_read() which may return negative values. The current logi
> >>> doesn't check such errors, causing colorspace to be reported
> >>> on a wrong way at adv76xx_log_status().
> >>>
> >>> If I/O error happens there, print a different message, instead
> >>> of reporting bogus messages to userspace.
> >>>
> >>> Fixes: 54450f591c99 ("[media] adv7604: driver for the Analog Devices ADV7604 video decoder")
> >>> Cc: stable@vger.kernel.org    
> >>
> >> Not really a fix since this would just affect logging for debugging
> >> purposes. I would personally just drop the Fixes and Cc tag.  
> > 
> > The issue is on a VIDIOC_ ioctl, so part of media API. Ok, this is
> > used only for debugging purposes and should, instead be implemented
> > via debugfs, etc, but, in summary: it is what it is: part of the V4L2
> > uAPI.  
> 
> The ioctl, yes, but what it logs to the kernel log isn't part of the ABI.
> That can change.

Sure, logs can change, but this is an user-visible bug.

> I think it is overkill to send this to stable for an old chip that almost
> nobody uses, and that requires an i2c read to go wrong for it to produce
> a wrong debug message. It seems an unnecessary waste of time.

Agreed. Will drop cc stable.

> > 
> > -
> > 
> > Now, the question about what should have Fixes: tag and what
> > shouldn't is a different matter. I've saw long discussions about
> > that at the kernel mailing lists. In the particular case of y2038,
> > I'm pretty sure I saw some of them with Fixes tag on it.  
> 
> But patch 13/13 doesn't affect the operation either, again it is just
> an incorrect log message that can only go wrong if Pulse-Eight still
> sells that device in 2038 with a firmware build date >= 2038. 

> And v6.12 is guaranteed to be EOL in 2038 :-)

We can't count on it. Civil infrastructure is now working with a 10 years
SLTS:

	https://www.linuxfoundation.org/press/civil-infrastructure-platform-expands-slt-stable-kernel-program

I heard somewhere that having a 15 years or 20 years stable Kernel is a
need for certain usages.

Even commercial distros have a minimum of 10 years as LTS.

Suse is now working with a 13-years support. Both Canonical and Red Hat
announced a 12-years ELTS support. As they usually takes the last year's 
LTS Kernel, it means support will end with a 14 years old Kernel (so, 
support will end in 2037 or 2038 if they release an LTS distro next year),
and don't decide to extend it further.

I also heard during LPC that there's an increased pressure from Linux
customers from commercial distros to extend it even further.


Thanks,
Mauro