Re: [Regression 3.1->3.2, bisected] UVC-webcam: kernel panic when starting capturing

["Frank Schäfer" <fschaefer.oss@googlemail.com>]

Am 15.07.2012 14:07, schrieb Laurent Pinchart:
> Hi Frank,
>
> Thanks for the report.
>
> On Thursday 12 July 2012 21:07:56 Frank Schäfer wrote:
>> Hi,
>>
>> when I start capturing from the UVC-webcam 2232:1005 ("WebCam
>> SCB-0385N") of my netbook, I get a kernel panic.
>> You can find a screenshot of the backtrace here:
>>
>> http://imageshack.us/photo/my-images/9/img125km.jpg/
>>
>>
>> This is a regression which has been introduced between kernel 3.2-rc2
>> and 3.2-rc3 with the following commit:
>>
>>
>> 3afedb95858bcc117b207a7c0a6767fe891bdfe9 is the first bad commit
>> commit 3afedb95858bcc117b207a7c0a6767fe891bdfe9
>> Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>> Date:   Thu Nov 3 07:24:34 2011 -0300
>>
>>     [media] uvcvideo: Don't skip erroneous payloads
>>
>>     Instead of skipping the payload completely, which would make the
>>     resulting image corrupted anyway, store the payload normally and mark
>>     the buffer as erroneous. If the no_drop module parameter is set to 1 the
>> buffer will then be passed to userspace, and tt will then be up to the
>> application to decide what to do with the buffer.
>>
>>     Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>>     Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
> I'm puzzled. Your screenshot shows the uvc_video_stats_decode() function in 
> the stack trace, but that function wasn't present in 
> 3afedb95858bcc117b207a7c0a6767fe891bdfe9. Could you please send me a stack 
> trace corresponding to 3afedb95858bcc117b207a7c0a6767fe891bdfe9 ?
>
> Your stack trace looks similar to the problem reported in 
> https://bugzilla.redhat.com/show_bug.cgi?id=836742. 
> 3afedb95858bcc117b207a7c0a6767fe891bdfe9 might have introduced a different 
> bug, possibly fixed in a later commit.
Hmm... you're right.
The screenshot I've sent to you was made during the bisection process at
a commit somewhere between 3.2-rc7 and 3.2-rc8.
It seems that this one is slightly different from the others.


This one is made at commit 3afedb95858bcc117b207a7c0a6767fe891bdfe9 (the
first bad commit):

http://imageshack.us/photo/my-images/811/img130hv.jpg


and this one is made at 3.5.rc6+:

http://imageshack.us/photo/my-images/440/img127u.jpg


Regards,
Frank Schäfer