Re: gspca_zc3xx oops - 2.6.27-rc1

["Parag Warudkar" <parag.warudkar@gmail.com>]

On Sun, Aug 3, 2008 at 3:37 AM, Rabin Vincent <rabin@rab.in> wrote:

>  2b:   0f b6 37                movzbl (%edi),%esi <---- offender
>  2e:   0f af f0                imul   %eax,%esi
>  31:   8d b6 00 00 00 00       lea    0x0(%esi),%esi
>  37:   0f b6 83 00 dc 15 f9    movzbl -0x6ea2400(%ebx),%eax
>
> %edi is Tgamma, and it is NULL because sd->gamma was 0, and the zeroth element
> of gamma_tb was loaded.

Yep - I arrived at the same conclusion and sent a patch few minutes
before I saw your mail.
I am clueless about V4L and gspca workings but I chose a different
approach to fix this -
http://marc.info/?l=linux-kernel&m=121774817612391&w=2 .

>
> Now sd->gamma shouldn't be zero because in sd_ctrls, the minimum value for it
> is set to 1.  This range should be checked by vidioc_s_ctrl in gspca.c, and we
> have this there:
>
>               if (ctrl->value < ctrls->qctrl.minimum
>                   && ctrl->value > ctrls->qctrl.maximum)
>                        return -ERANGE;
>

Sounds more appropriate but I am not sure how vidioc_s_ctrl leads to
the call trace in the OOPS - at least it doesn't show up there.


Thanks

Parag