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

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Frank,

On Sunday 15 July 2012 21:39:47 Frank Schäfer wrote:
> Am 15.07.2012 14:07, schrieb Laurent Pinchart:
> > 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

Thank you. Could you please try the patch I've attached to 
https://bugzilla.redhat.com/show_bug.cgi?id=836742 ?

-- 
Regards,

Laurent Pinchart