Bug#639948: libavcodec.so.53: ffplay produces a coredump on arch ppc

[Reinhard Tartler]

severity 639948 normal
tags 639948 upstream
stop

On Thu, Sep 01, 2011 at 09:28:48 (CEST), Elimar Riesebieter wrote:

> * Reinhard Tartler [110901 08:00 +0200]:
>
> [...]
>> Can you please redo the backtrace with the package ffmpeg-dbg installed?
>
> [Thread debugging using libthread_db enabled]
> Core was generated by `ffplay 03-G3_Live_in_Denver-Joe_Satriani-Starry_Night.aac'.
> Program terminated with signal 11, Segmentation fault.
> #0  0x0f6ff2e4 in ff_fft_calc_altivec () at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/ppc/fft_altivec_s.S:447
> 447     /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/ppc/fft_altivec_s.S: Datei oder Verzeichnis nicht gefunden.
>         in /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/ppc/fft_altivec_s.S
> (gdb) bt
> #0  0x0f6ff2e4 in ff_fft_calc_altivec () at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/ppc/fft_altivec_s.S:447
> #1  0x0f6feaa8 in ff_imdct_half_altivec (s=<optimized out>, output=<optimized out>, input=<optimized out>)
>     at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/ppc/fft_altivec.c:93
> #2  0x0f437ce8 in imdct_and_windowing (ac=0x10065e00, sce=0x4917f0c0) at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/aacdec.c:1856

That gives some more insight. It avcodec tries to decode some AAC audio,
and causes some altivec optimized functions to segfault in
ff_fft_calc_altivec. Can you elaborate what kind of powerpc you have? 

> #3  0x0f43caa8 in spectral_to_sample (ac=<optimized out>) at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/aacdec.c:2015
> #4  aac_decode_frame_int (avctx=<optimized out>, data=0x49150020, data_size=0x4914e938, gb=<optimized out>)
>     at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/aacdec.c:2170
> #5  0x0f43ccec in aac_decode_frame (avctx=<optimized out>, data=<optimized out>, data_size=<optimized out>, avpkt=<optimized out>)
>     at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/aacdec.c:2216
> #6  0x0f77f25c in avcodec_decode_audio3 (avctx=0x10065a00, samples=<optimized out>, frame_size_ptr=<optimized out>, avpkt=<optimized out>)
>     at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavcodec/utils.c:726
> #7  0x0ff3f924 in try_decode_frame (avpkt=0x100632a0, st=0x10061a00) at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavformat/utils.c:2104
> #8  av_find_stream_info (ic=0x10047e00) at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/libavformat/utils.c:2388
> #9  0x10008ac8 in decode_thread (arg=0x48882020) at /build/buildd-libav_0.7.1-3-powerpc-vCfdgT/libav-0.7.1/ffplay.c:2362
> #10 0x0f18f63c in ?? () from /usr/lib/libSDL-1.2.so.0
> #11 0x0f1d7e18 in ?? () from /usr/lib/libSDL-1.2.so.0
> #12 0x0f1457a0 in start_thread () from /lib/powerpc-linux-gnu/libpthread.so.0
> #13 0x0f09c9f0 in clone () from /lib/powerpc-linux-gnu/libc.so.6
>
>> Also, does removing the file /usr/lib/altivec/libavcodec.so.53 help?
>
> It helps, but was installed by libavcodec53 4:0.7.1-3?

well, that's the package you've filed the bug against.

> $ dpkg -L libavcodec53 | grep altivec
>
> /usr/lib/altivec
> /usr/lib/altivec/libavcodec.so.53.5.0
> /usr/lib/altivec/libavcodec.so.53
>
> There is more libav stuff in /usr/lib/altivec.

Indeed, and that's intended. The problem is that it doesn't work for
you.

In any case, we need as sample to reproduce this ourselves. Since the
filename '03-G3_Live_in_Denver-Joe_Satriani-Starry_Night.aac' indicates
that the file might be rather longish, maybe you could share a part from
that still exposes the bug? Try:

 dd if=sample-file of=small-sample-file bs=1024 count=10000

As this is definitly an upstream bug, please report this issue at the
upstream bugzilla:

 http://bugzilla.libav.org/enter_bug.cgi

and provide all information in this bug and potentially more as
requested.

-- 
Gruesse/greetings,
Reinhard Tartler, KeyID 945348A4