[ATrpms-users] vlc crashes

[Axel Thimm]

On Wed, Jan 09, 2008 at 07:40:41PM -0500, Jeffrey J. Kosowsky wrote:
> Axel Thimm wrote at about 14:03:42 +0200 on Wednesday, January 9, 2008:
>  > On Wed, Jan 09, 2008 at 01:26:50AM -0500, Jeffrey J. Kosowsky wrote:
>  > > When I run vlc on some HD streams (piping getatsc to vlc), I get a
>  > > crash most but not all the time (using the exact same command).
>  > 
>  > Errors that are not deterministic usually point to non-intialized
>  > variables or to overwriting past their boundaries. Depending on what
>  > the value of the var (randomly) was or whether the overwritten memory
>  > was critical or not you get different results.
>  > 
>  > > *** glibc detected *** vlc: double free or corruption (!prev): 0x0991f808 ***
>  > 
>  > This means that there is a bug in the program trying to free twice the
>  > same memory. E.g. there is something wrong with the memory
>  > bookkeeping. In older distros or if one removed the glibc safety
>  > features (I think one can do so by environment vars) the error is not
>  > fatal and you may be lucky and not notice any effect. But as these
>  > bugs can be used for security exploits Fedora (since FC5?) by default
>  > kills such bad behaving programs.
>  > 
>  > E.g. the issue is a code issue - glibc detects it and kills the code.
>  > 
>  > > ======= Backtrace: =========
>  > > /lib/libc.so.6[0xc8dac1]
>  > > /lib/libc.so.6(cfree+0x90)[0xc910f0]
>  > > vlc[0x809ea5b]
>  > > /usr/lib/vlc/stream_out/libstream_out_transcode_plugin.so[0x5fcb24]
>  > > vlc(sout_InputSendBuffer+0x78)[0x8097f28]
>  > > vlc[0x80d1b3a]
>  > > vlc[0x80d5b0e]
>  > > vlc[0x80fd694]
>  > > vlc[0x80fe628]
>  > > vlc[0x8079ddd]
>  > > vlc[0x807b3ad]
>  > > /lib/libpthread.so.0[0xdb650b]
>  > > /lib/libc.so.6(clone+0x5e)[0xcf7b2e]
>  > 
>  > If you install the debuginfo package to vlc and glibc then you would
>  > get the names of the routines and maybe one would be able to guess
>  > what vlc was doing at that time (e.g. which sublibrary it is using etc.)
> 
> Any words of wisdom on the other (non-critical) "errors" mentioned in
> the log file:
> 
>  >  > 1. libdvdread: Can't stat - No such file or directory
>  >  >   (but I do have libdvdread-0.9.7-3.fc8.i386.rpm)

It mentions "-" which vlc simply passes down to libdvdread,
e.g. libdvdread thinks it should examine the file "-" not stdin (which
can't be reused anyway), so consider this a bad API between vlc and
libdvdread.

>  >  > 2. libdvdnav: vm: faild to open/read the DVD
>  >  > 	 (but I was using an input stream on stdin and never
>  >  > 	 referenced a DVD though the format is mpeg2)

Exactly, so it's a bad API again.

>  >  > 3. libdvbpsi error (PSI decoder): TS discontinuity (received 2, expected 0) for PID 0

TS probably means Transport Stream, e.g in contrast to a PS Program
Stream. Probably a demuxing issue in the stream itself.

>  >  > 4. No accelerated IMDCT transform found
> 
> Basically, I just want to know what the errors mean and what I need to
> do to fix them or at least get rid of them.

In contrast to the double free/malloc issue these are cosmetic, I
think they will just clutter your console when the true problem is
fixed/worked around.
-- 
Axel.Thimm at ATrpms.net
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
Url : http://lists.atrpms.net/pipermail/atrpms-users/attachments/20080110/8b9debe7/attachment.bin