* Question about implementation of __qbuf_dmabuf() in videobuf2-core.c
@ 2014-04-23 0:18 n179911
2014-04-23 7:24 ` Hans Verkuil
0 siblings, 1 reply; 4+ messages in thread
From: n179911 @ 2014-04-23 0:18 UTC (permalink / raw)
To: linux-media
In __qbuf_dmabuf(), it check the length and size of the buffer being
queued, like this:
http://lxr.free-electrons.com/source/drivers/media/v4l2-core/videobuf2-core.c#L1158
My question is why the range check is liked this:
1158 if (planes[plane].length < planes[plane].data_offset +
1159 q->plane_sizes[plane]) {
.....
Isn't planes[plane].length + planes[plane].data_offset equals to
q->plane_sizes[plane]?
So the check should be?
if (planes[plane].length < q->plane_sizes[plane] - planes[plane].data_offset)
Please tell me what am I missing?
Thank you
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Question about implementation of __qbuf_dmabuf() in videobuf2-core.c
2014-04-23 0:18 Question about implementation of __qbuf_dmabuf() in videobuf2-core.c n179911
@ 2014-04-23 7:24 ` Hans Verkuil
2014-04-29 17:27 ` n179911
0 siblings, 1 reply; 4+ messages in thread
From: Hans Verkuil @ 2014-04-23 7:24 UTC (permalink / raw)
To: n179911, linux-media
On 04/23/2014 02:18 AM, n179911 wrote:
> In __qbuf_dmabuf(), it check the length and size of the buffer being
> queued, like this:
> http://lxr.free-electrons.com/source/drivers/media/v4l2-core/videobuf2-core.c#L1158
>
> My question is why the range check is liked this:
>
> 1158 if (planes[plane].length < planes[plane].data_offset +
> 1159 q->plane_sizes[plane]) {
It's a bug. It should be:
if (planes[plane].length < q->plane_sizes[plane]) {
This has been fixed in our upstream code and will appear in 3.16.
Regards,
Hans
> .....
>
> Isn't planes[plane].length + planes[plane].data_offset equals to
> q->plane_sizes[plane]?
>
> So the check should be?
> if (planes[plane].length < q->plane_sizes[plane] - planes[plane].data_offset)
>
> Please tell me what am I missing?
>
> Thank you
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Question about implementation of __qbuf_dmabuf() in videobuf2-core.c
2014-04-23 7:24 ` Hans Verkuil
@ 2014-04-29 17:27 ` n179911
2014-05-05 10:19 ` Hans Verkuil
0 siblings, 1 reply; 4+ messages in thread
From: n179911 @ 2014-04-29 17:27 UTC (permalink / raw)
To: Hans Verkuil; +Cc: linux-media
Hi,
Is there a work around for this bug without upgrading to 3.16 kernel?
Is it safe to manually set the length to be data_offset + size + 1 to make sure
planes[plane].length is greater than planes[plane].data_offset +
q->plane_sizes[plane]?
Thank you.
On Wed, Apr 23, 2014 at 12:24 AM, Hans Verkuil <hverkuil@xs4all.nl> wrote:
> On 04/23/2014 02:18 AM, n179911 wrote:
>> In __qbuf_dmabuf(), it check the length and size of the buffer being
>> queued, like this:
>> http://lxr.free-electrons.com/source/drivers/media/v4l2-core/videobuf2-core.c#L1158
>>
>> My question is why the range check is liked this:
>>
>> 1158 if (planes[plane].length < planes[plane].data_offset +
>> 1159 q->plane_sizes[plane]) {
>
> It's a bug. It should be:
>
> if (planes[plane].length < q->plane_sizes[plane]) {
>
> This has been fixed in our upstream code and will appear in 3.16.
>
> Regards,
>
> Hans
>
>> .....
>>
>> Isn't planes[plane].length + planes[plane].data_offset equals to
>> q->plane_sizes[plane]?
>>
>> So the check should be?
>> if (planes[plane].length < q->plane_sizes[plane] - planes[plane].data_offset)
>>
>> Please tell me what am I missing?
>>
>> Thank you
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-media" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Question about implementation of __qbuf_dmabuf() in videobuf2-core.c
2014-04-29 17:27 ` n179911
@ 2014-05-05 10:19 ` Hans Verkuil
0 siblings, 0 replies; 4+ messages in thread
From: Hans Verkuil @ 2014-05-05 10:19 UTC (permalink / raw)
To: n179911; +Cc: linux-media
On 04/29/2014 07:27 PM, n179911 wrote:
> Hi,
>
> Is there a work around for this bug without upgrading to 3.16 kernel?
>
> Is it safe to manually set the length to be data_offset + size + 1 to make sure
>
> planes[plane].length is greater than planes[plane].data_offset +
> q->plane_sizes[plane]?
Yes, that should be safe. However, if you are building the kernel yourself, then
I would recommend just fixing the kernel instead of working around it elsewhere.
Regards,
Hans
>
> Thank you.
>
> On Wed, Apr 23, 2014 at 12:24 AM, Hans Verkuil <hverkuil@xs4all.nl> wrote:
>> On 04/23/2014 02:18 AM, n179911 wrote:
>>> In __qbuf_dmabuf(), it check the length and size of the buffer being
>>> queued, like this:
>>> http://lxr.free-electrons.com/source/drivers/media/v4l2-core/videobuf2-core.c#L1158
>>>
>>> My question is why the range check is liked this:
>>>
>>> 1158 if (planes[plane].length < planes[plane].data_offset +
>>> 1159 q->plane_sizes[plane]) {
>>
>> It's a bug. It should be:
>>
>> if (planes[plane].length < q->plane_sizes[plane]) {
>>
>> This has been fixed in our upstream code and will appear in 3.16.
>>
>> Regards,
>>
>> Hans
>>
>>> .....
>>>
>>> Isn't planes[plane].length + planes[plane].data_offset equals to
>>> q->plane_sizes[plane]?
>>>
>>> So the check should be?
>>> if (planes[plane].length < q->plane_sizes[plane] - planes[plane].data_offset)
>>>
>>> Please tell me what am I missing?
>>>
>>> Thank you
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-media" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>>
>>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-04-23 0:18 Question about implementation of __qbuf_dmabuf() in videobuf2-core.c n179911
2014-04-23 7:24 ` Hans Verkuil
2014-04-29 17:27 ` n179911
2014-05-05 10:19 ` Hans Verkuil
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