[FFmpeg-devel] [PATCH] Fix a crash when adding many video clips to a kdenlive project:

Michael Niedermayer michaelni at gmx.at
Wed Aug 31 15:52:11 CEST 2011

On Wed, Aug 31, 2011 at 04:04:30PM +0300, Mikko Rapeli wrote:
> On Wed, Aug 31, 2011 at 02:38:31PM +0200, Michael Niedermayer wrote:
> > > -    av_opt_free(avctx);
> > >      av_freep(&avctx->priv_data);
> > > +    av_opt_free(avctx);
> > 
> > Can you explain why you think the order of these 2 functions can
> > trigger a bug ?
> Granted, I did not dig too deep and don't know about ffmpeg much. I thought
> av_opt_free was freeing also the priv_data pointer so glibc would call
> it a free of an unallocated address.

av_opt_free() isnt supposed to free priv_data, also even if it did
it would set it to NULL
so this explanation doesnt look likely to me

> This showed up as a crash when adding new video clips to a kdenlive project
> and the crash has been gone since I added this change.
> > also valgrind output should help in understanding the bug
> I might be able dig this up.

please do

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is dangerous to be right in matters on which the established authorities
are wrong. -- Voltaire
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