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

Michael Niedermayer michaelni at gmx.at
Mon Sep 26 22:27:28 CEST 2011


On Fri, Sep 23, 2011 at 10:35:20PM +0300, Mikko Rapeli wrote:
> On Wed, Aug 31, 2011 at 03:52:11PM +0200, Michael Niedermayer wrote:
> > 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 error has not reproduced without the patch until today, ffmpeg from
> Sept 1st at git commit acc3c380cb010451e8e336b622e7ae446709d5c2. Unfortunately
> it is hard to repeat and running valgrind isn't an option until I know
> how to hit this.

is this happening on more than one machine ?
if its just one, i would suggest memtest

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Dictatorship naturally arises out of democracy, and the most aggravated
form of tyranny and slavery out of the most extreme liberty. -- Plato
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