[ATrpms-users] vlc crashes

[Axel Thimm]

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.)
-- 
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/20080109/d70ad94c/attachment.bin