ffmpeg crashed with SIGSEGV in avformat_open_input()

[David Kastrup]

Startup message stated:
ffmpeg -f libdc1394 -video_size 640x480 -framerate 15 -i fw.0 -pix_fmt bgr24 -f v4l2 /dev/video0
ffmpeg version 3.3.3-1ubuntu1 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 6.4.0 (Ubuntu 6.4.0-2ubuntu1) 20170724
  configuration: --prefix=/usr --extra-version=1ubuntu1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  WARNING: library configuration mismatch
  avcodec configuration: --prefix=/usr --extra-version=1ubuntu1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared --enable-version3 --disable-doc --disable-programs --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libtesseract --enable-libvo_amrwbenc --enable-netcdf
  libavutil 55. 58.100 / 55. 58.100
  libavcodec 57. 89.100 / 57. 89.100
  libavformat 57. 71.100 / 57. 71.100
  libavdevice 57. 6.100 / 57. 6.100
  libavfilter 6. 82.100 / 6. 82.100
  libavresample 3. 5. 0 / 3. 5. 0
  libswscale 4. 6.100 / 4. 6.100
  libswresample 2. 7.100 / 2. 7.100
  libpostproc 54. 5.100 / 54. 5.100
Segmentation fault (core dumped)

I don't know whether the reported library version mismatch in the warning might be relevant.

ProblemType: Crash
DistroRelease: Ubuntu 17.10
Package: ffmpeg 7:3.3.3-1ubuntu1
ProcVersionSignature: Ubuntu 4.11.0-13.19-lowlatency 4.11.12
Uname: Linux 4.11.0-13-lowlatency x86_64
ApportVersion: 2.20.6-0ubuntu5
Architecture: amd64
CurrentDesktop: XFCE
Date: Tue Aug 15 11:42:18 2017
ExecutablePath: /usr/bin/ffmpeg
InstallationDate: Installed on 2011-10-14 (2131 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111011)
ProcCmdline: ffmpeg -f libdc1394 -video_size 640x480 -framerate 15 -i fw.0 -pix_fmt bgr24 -f v4l2 /dev/video0
SegvAnalysis:
 Segfault happened at: 0x7f6f755ffb7d: mov 0xa8(%rdi),%eax
 PC (0x7f6f755ffb7d) ok
 source "0xa8(%rdi)" (0x000000a8) not located in a known VMA region (needed readable region)!
 destination "%eax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: ffmpeg
StacktraceTop:
 ?? () from /usr/lib/x86_64-linux-gnu/libavdevice.so.57
 avformat_open_input () from /usr/lib/x86_64-linux-gnu/libavformat.so.57
 ?? ()
 ?? ()
 main ()
Title: ffmpeg crashed with SIGSEGV in avformat_open_input()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin audio cdrom dialout fax floppy lpadmin lxd plugdev pulse-access sambashare

[Carl Eugen Hoyos (cehoyos)]

Please either install debug libraries to make the backtrace useful or (even better) recompile current FFmpeg git head with "./configure --enable-libdc1394 && make ffmpeg" (likely needs libdc1394-22-dev, no FFmpeg installation required) and provide a full backtrace with symbols.

I consider it possible that dc1394 support in FFmpeg has not been tested for a year, sorry!

[James Cowgill (jcowgill)]

cehoyos, here is a stacktrace with symbols based on the core dump attached earlier.

The point where it segfaults is:
    /* Select MAX Speed possible from the cam */
    if (dc1394->camera->bmode_capable>0) {

According to GDB, dc1394->camera is NULL.

[Carl Eugen Hoyos (cehoyos)]

I have sent an untested patch that is meant to fix this issue:
http://ffmpeg.org/pipermail/ffmpeg-devel/2017-August/214977.html

Feel free to test, Carl Eugen