Date: Mon, 5 Sep 2011 09:40:21 +0800 From: "Alex V. Petrov" <alexvpetrov@gmail.com> To: Hans de Goede <hdegoede@redhat.com> Cc: freebsd-multimedia@freebsd.org Subject: Re: Fwd: I have problem with libv4l Message-ID: <CAAtgPUpxhT2SDS09W5e%2B6_0zpX5R%2B%2Bv=HqBHFsjuMtbJkSrsqA@mail.gmail.com> In-Reply-To: <4E6396F1.6030704@redhat.com> References: <201108311418.53651.hselasky@c2i.net> <4E6396F1.6030704@redhat.com>
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2011/9/4 Hans de Goede <hdegoede@redhat.com> > Hi, > > On 08/31/2011 02:18 PM, Hans Petter Selasky wrote: > >> >> ---------- Forwarded Message ---------- >> >> Subject: I have problem with libv4l >> Date: Wednesday 31 August 2011, 13:44:37 >> From: "Alex V. Petrov"<alexvpetrov@gmail.com> >> To: freebsd-multimedia@freebsd.org >> CC: hselasky@freebsd.org >> >> Hi all! >> >> In June, after updating libv4l, my webcam (Mustek Gsmart mini 3) is not >> working (I use pwcview). >> >> $ pwcview >> Webcam set to: 320x240 (sif) at 5 fps >> Segmentation fault (core dumped) >> >> gdb: >> #0 0x0000000800ae1bfb in jpeg_idct_16x16 (cinfo=Variable "cinfo" is not >> available.) at jidctint.c:2760 >> 2760 outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp20 + tmp0, >> [New Thread 803807400 (LWP 101450/pwcview)] >> > > Hmm, this points to a bug in libjpeg, since recent versions of libv4l > have switched to using libjpeg for jpeg decompression, because of speed > reasons, except for some special cases (because some cams produce non > standard compliant JPEG data and the tinyjpeg copy bundled with libv4l > contains several patches to deal with this). > > Can you tell me the usb-id / chipset of your camera, so that I can > try to reproduce? I likely won't be able to reproduce though. What > version of libjpeg are you using, and with which compiler is it > build ? > > Can you perhaps try to reproduce this under Linux? Preferably > Fedora 15? > > There are 2 solutions to this problem: > 1) If it is specific to this webcam / chipset, add a quirk to libv4l's > quirk table to use the embedded tinyjpeg copy > > 2) Figure out what is causing libjpeg to crash and fix it. > > > With 2 being preferable since a segfault inside libjpeg (assuming it > is not the way libv4l uses libjpeg for now), does smell like a security > issue to me. > > Regards, > > Hans > ugen0.2: <product 0xc520 vendor 0x055f> at usbus0, cfg=0 md=HOST spd=FULL (12Mbps) pwr=ON jpeg-8_3 with cc (GCC) 4.2.2 20070831 prerelease [FreeBSD] Fedora 15 will try later. -- ---------------------- Alex V. Petrov
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