[FFmpeg-trac] #8213(undetermined:new): Division by zero at libavcodec/lpc.h

[FFmpeg]

#8213: Division by zero at libavcodec/lpc.h
-------------------------------------+-------------------------------------
             Reporter:  Suhwan       |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:  ubsan        |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 {{{
 libavcodec/lpc.h:189:15: runtime error: division by zero
 SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior
 libavcodec/lpc.h:189:15 in

 Thread 1 "ffmpeg_g" hit Breakpoint 1, compute_lpc_coefs
 (autoc=0x7fffffff74c8,
     lpc=<optimized out>, lpc_stride=32, fail=0, normalize=1,
     max_order=<optimized out>) at libavcodec/lpc.h:189
 189                 r /= err;
 (gdb) bt
 #0  compute_lpc_coefs (autoc=0x7fffffff74c8, lpc=<optimized out>,
 lpc_stride=32,
     fail=0, normalize=1, max_order=<optimized out>) at
 libavcodec/lpc.h:189
 #1  ff_lpc_calc_coefs (s=0x633000080980, samples=0x633000070830,
 blocksize=4096,
     min_order=4, max_order=6, precision=9, coefs=<optimized out>,
     shift=<optimized out>, lpc_type=<optimized out>, lpc_passes=2,
 omethod=0,
     min_shift=<optimized out>, max_shift=<optimized out>,
     zero_shift=<optimized out>) at libavcodec/lpc.c:232
 #2  0x00000000068f926e in calc_predictor_params (s=0x633000070800,
     ch=<optimized out>) at libavcodec/alacenc.c:169
 #3  write_element (s=0x633000070800, element=TYPE_SCE, instance=0,
     samples0=<optimized out>, samples1=0x0) at libavcodec/alacenc.c:423
 #4  0x00000000068f26c3 in write_frame (s=0x633000070800, avpkt=<optimized
 out>,
     samples=0x616000009c80) at libavcodec/alacenc.c:478
 #5  0x00000000068f0b4e in alac_encode_frame (avctx=0x619000002380,
     avpkt=<optimized out>, frame=<optimized out>,
 got_packet_ptr=0x7fffffffb3c0)
     at libavcodec/alacenc.c:640
 #6  0x000000000314964d in avcodec_encode_audio2 (avctx=0x619000002380,
     avpkt=0x60e000005180, frame=0x616000009c80,
 got_packet_ptr=0x7fffffffb3c0)
     at libavcodec/encode.c:203
 #7  0x0000000003151c20 in do_encode (avctx=<optimized out>,
 frame=0x616000009c80,
     got_packet=0x7fffffffb3c0) at libavcodec/encode.c:374
 #8  0x00000000031513ef in avcodec_send_frame (avctx=<optimized out>,
     frame=0x616000009c80) at libavcodec/encode.c:420
 #9  0x0000000000653b5d in do_audio_out (of=0x60a000000180,
 ost=0x616000007880,
     frame=<optimized out>) at fftools/ffmpeg.c:939
 #10 reap_filters (flush=0) at fftools/ffmpeg.c:1513
 #11 0x00000000005e73a3 in transcode_step () at fftools/ffmpeg.c:4648
 #12 transcode () at fftools/ffmpeg.c:4692
 #13 0x00000000005db65c in main (argc=<optimized out>, argv=<optimized
 out>)
     at fftools/ffmpeg.c:4894
 }}}

 How to reproduce:
 {{{
 % ./ffmpeg_g -t 2 -stream_loop 14 -y -i guitar_acoustic_021-105-025.wav
 -loglevel 0 -map 0 -c copy -c:a:0 alac -disposition:s:8 vp8_v4l2m2m
 -disposition:s:8 pgmyuv -aframes 66 -ab 389k -ar 48000 -ac 1 -b:v 608k
 tmp.dts

 ffmpeg version N-95160-g9fdc2c7bc4 Copyright (c) 2000-2019 the FFmpeg
 developers
 built with clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
 configuration: --cc=clang --cxx=clang++ --ld=clang --enable-debug
 --toolchain=clang-asan
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8213>
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