[FFmpeg-devel] [PATCH 2/2] lavfi/sink_buffer: implement libav compatibility API.

[Michael Niedermayer]

On Thu, Sep 27, 2012 at 04:51:15PM +0200, Nicolas George wrote:
> Le quintidi 5 vendémiaire, an CCXXI, Michael Niedermayer a écrit :
> > for me it seems crashing at fate-flic-magiccarpet, which it does not
> > do with incompatible_fork_abi
> > 
> > but the patch should be ok as i didnt notice a change when
> > incompatible_fork_abi is enabled
> > 
> > Program received signal SIGSEGV, Segmentation fault.
> > 0x00007ffff795e41f in vsink_init (ctx=0x63fb20, args=0x0, opaque=0x110) at libavfilter/sink_buffer.c:207
> 
> That is very strange, and it does not happen for me:
> 
> 
> avconv_filter.c:
> 
>     ret = avfilter_graph_create_filter(&ofilter->filter,
>                                        avfilter_get_by_name("buffersink"),
>                                        name, NULL, NULL, fg->graph);
> 
> avfilter_graph_create_filter (args and opaque are the NULL above):
> 
>     if ((ret = avfilter_init_filter(*filt_ctx, args, opaque)) < 0)
> 
> avfilter_init_filter:
> 
>     if (filter->filter->init_opaque)
>         ret = filter->filter->init_opaque(filter, args, opaque);
> 
> avfilter_vsink_ffbuffersink:
> 
>         .init_opaque = vsink_init,
> 
> I do not understand how that 0x110 can arrive here. Does valgrind report
> errors earlier in the run?

it appears that the crash does not happen in valgrind, instead it
shows:

[graph 0 input from stream 0:0 @ 0xff1fa20] Flat options syntax is deprecated, use key=value pairs
==8191== Conditional jump or move depends on uninitialised value(s)
==8191==    at 0x50A0419: vsink_init (sink_buffer.c:207)
==8191==    by 0x506B04B: avfilter_init_filter (avfilter.c:611)
==8191==    by 0x506B2AB: avfilter_graph_create_filter (avfiltergraph.c:89)
==8191==    by 0x40C691: configure_output_video_filter.isra.6 (avconv_filter.c:192)
==8191==    by 0x40D1BF: configure_output_filter (avconv_filter.c:350)
==8191==    by 0x40D446: configure_filtergraph (avconv_filter.c:516)
==8191==    by 0x410C7F: transcode_init (avconv.c:1702)
==8191==    by 0x405C1B: main (avconv.c:2252)
==8191==
==8191== Use of uninitialised value of size 8
==8191==    at 0x50A041F: vsink_init (sink_buffer.c:207)
==8191==    by 0x506B04B: avfilter_init_filter (avfilter.c:611)
==8191==    by 0x506B2AB: avfilter_graph_create_filter (avfiltergraph.c:89)
==8191==    by 0x40C691: configure_output_video_filter.isra.6 (avconv_filter.c:192)
==8191==    by 0x40D1BF: configure_output_filter (avconv_filter.c:350)
==8191==    by 0x40D446: configure_filtergraph (avconv_filter.c:516)
==8191==    by 0x410C7F: transcode_init (avconv.c:1702)
==8191==    by 0x405C1B: main (avconv.c:2252)
==8191==
#tb 0: 1/14

note, this is with avconv version v0.8-2970-gede3d64, i didnt update
it since then

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

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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