[FFmpeg-trac] #6323(ffmpeg:new): ffmpeg unconnected filter outputs can cause OOM and segfault

[FFmpeg]

#6323: ffmpeg unconnected filter outputs can cause OOM and segfault
-------------------------------------+-------------------------------------
               Reporter:  cus        |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  important  |              Component:  ffmpeg
                Version:  git-       |               Keywords:  regression
  master                             |  SIGSEGV
             Blocked By:             |               Blocking:
Reproduced by developer:  0          |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 Summary of the bug:

 Since af1761f7b5b1b72197dc40934953b775c2d951cc ffmpeg no longer detects an
 unconnected filter output in some cases. This causes frames to queue up
 and eventually cause an OOM and a segmentation fault.

 How to reproduce:
 {{{
 ffmpeg -f lavfi -i testsrc -f lavfi -i testsrc -filter_complex
 "[0:v][1:v]psnr[out]" -f null none

 ffmpeg version N-85544-g9e86a61 Copyright (c) 2000-2017 the FFmpeg
 developers
   built with gcc 4.8 (SUSE Linux)
   configuration: --disable-vaapi --enable-vdpau --enable-gpl --enable-
 libfreetype --enable-libzvbi --enable-libass --enable-frei0r --enable-
 openssl --enable-nonfree --enable-libx264 --enable-libfdk-aac --enable-
 nonfree --enable-libvorbis --enable-decklink --enable-libmp3lame --enable-
 openal --enable-libiec61883
   libavutil      55. 61.100 / 55. 61.100
   libavcodec     57. 92.100 / 57. 92.100
   libavformat    57. 72.101 / 57. 72.101
   libavdevice    57.  7.100 / 57.  7.100
   libavfilter     6. 84.101 /  6. 84.101
   libswscale      4.  7.101 /  4.  7.101
   libswresample   2.  8.100 /  2.  8.100
   libpostproc    54.  6.100 / 54.  6.100
 Input #0, lavfi, from 'testsrc':
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 320x240
 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
 Input #1, lavfi, from 'testsrc':
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #1:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 320x240
 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
 Stream mapping:
   Stream #0:0 (rawvideo) -> psnr:main (graph 0)
   Stream #1:0 (rawvideo) -> psnr:reference (graph 0)
   Stream #0:0 -> #0:0 (rawvideo (native) -> wrapped_avframe (native))
 Press [q] to stop, [?] for help
 OST: 0x255a920
 Output #0, null, to 'none':
   Metadata:
     encoder         : Lavf57.72.101
     Stream #0:0: Video: wrapped_avframe, rgb24, 320x240 [SAR 1:1 DAR 4:3],
 q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
     Metadata:
       encoder         : Lavc57.92.100 wrapped_avframe
 testsrc: Cannot allocate memory
 Segmentation fault (core dumped)

 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6323>
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