Bug#627818: ffmpeg segmentation fault __memcpy_ssse3 () at ../sysdeps/x86_64/multiarch/memcpy-ssse3.S:119

[Andres Mejia]

On Wed, May 25, 2011 at 4:51 PM, Marco Mattiolo
<marco.mattiolo at hotmail.it> wrote:
> Il 25/05/2011 08:47, Reinhard Tartler ha scritto:
>>
>> Can you please try the ffmpeg package from experimental (0.7) as well?
>> In any case, please share the .flv file, we really need to be able to
>> reproduce ourselves.
>
> Ok: ffmpeg from experimental works.
>
> The problem isn't video-specific, today I tried plenty of videos downloaded
> with youtube-dl, and all weren't able to convert into vorbis using ffmpeg.
> So I looked for a tiny video to attach, you can also get typing "youtube-dl
> http://www.youtube.com/watch?v=ELiKge89VAw".
>
> Il 25/05/2011 01:29, Romain Beauxis ha scritto:
>>
>> Hi all,
>> I ran into a similar bug in the recent past that was due to frame
>> memory not being aligned. Memory alignment is required to use SSE
>> optimisations. Maybe that is the issue here too?
>
> I don't know: how could I check it?
>
> Thank you
> Marco
>
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Note the following news of a recent upload of eglibc.

eglibc (2.13-3) unstable; urgency=low

  Starting with version 2.13, eglibc provides an SSSE3 optimized version
  of memcpy() on the amd64 architecture. This version might copy memory
  backward in some conditions, which causes issues if the source and
  destination overlap. memmove() should be used in such cases, but some
  programs still wrongly use memcpy().

  For this reason, on the amd64 architecture the Debian package provides
  two wrappers which can be use to workaround and/or debug the issue:
  - /usr/lib/libc/memcpy-preload.so simply replace all calls to memcpy()
    by a call to memmove()
  - /usr/lib/libc/memcpy-syslog-preload.so does the same, but in addition
    logs (with rate limit) the issue to syslog, so that it can be
    detected and fixed.

  To use these wrapper on a single binary, the easiest way is to use the
  LD_PRELOAD environment variable:
  - LD_PRELOAD=/usr/lib/libc/memcpy-preload.so /path/to/binary
  - LD_PRELOAD=/usr/lib/libc/memcpy-syslog-preload.so /path/to/binary

  For system-wide usage, it is possible to add the path of one of the
  wrapper to /etc/ld.so.preload.

  For more details about the issue, please see:
    http://bugs.debian.org/625521
    http://sourceware.org/bugzilla/show_bug.cgi?id=12518

 -- Aurelien Jarno <aurel32 at debian.org>  Wed, 11 May 2011 22:15:31 +0200


-- 
Regards,
Andres Mejia