`mkvalidator` v0.6.0 crashes and `master` segfaults against sample `.mkv`

[xlikewise]

This happens against real video files too, but this is a short repro using source builds on Linux.

Repro:

1. Generate dummy video

/mnt/tmp/ # ffmpeg -f lavfi -i color=size=1280x720:duration=5:rate=25:color=black -f lavfi -i anullsrc=r=44100:cl=stereo -c:v libx264 -c:a aac -shortest dummy.mkv
ffmpeg version 6.1.2 Copyright (c) 2000-2024 the FFmpeg developers
  built with gcc 14.2.0 (Alpine 14.2.0)
  configuration: --prefix=/usr --disable-librtmp --disable-lzma --disable-static --disable-stripping --enable-avfilter --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libdrm --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libharfbuzz --enable-libmp3lame --enable-libopenmpt --enable-libopus --enable-libplacebo --enable-libpulse --enable-librav1e --enable-librist --enable-libsoxr --enable-libsrt --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-libzimg --enable-libzmq --enable-lto=auto --enable-lv2 --enable-openssl --enable-pic --enable-postproc --enable-pthreads --enable-shared --enable-vaapi --enable-vdpau --enable-version3 --enable-vulkan --optflags=-O3 --enable-libjxl --enable-libsvtav1 --enable-libvpl
  libavutil      58. 29.100 / 58. 29.100
  libavcodec     60. 31.102 / 60. 31.102
  libavformat    60. 16.100 / 60. 16.100
  libavdevice    60.  3.100 / 60.  3.100
  libavfilter     9. 12.100 /  9. 12.100
  libswscale      7.  5.100 /  7.  5.100
  libswresample   4. 12.100 /  4. 12.100
  libpostproc    57.  3.100 / 57.  3.100
Input #0, lavfi, from 'color=size=1280x720:duration=5:rate=25:color=black':
  Duration: N/A, start: 0.000000, bitrate: N/A
  Stream #0:0: Video: wrapped_avframe, yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 25 fps, 25 tbr, 25 tbn
Input #1, lavfi, from 'anullsrc=r=44100:cl=stereo':
  Duration: N/A, start: 0.000000, bitrate: 705 kb/s
  Stream #1:0: Audio: pcm_u8, 44100 Hz, stereo, u8, 705 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (wrapped_avframe (native) -> h264 (libx264))
  Stream #1:0 -> #0:1 (pcm_u8 (native) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 0x7f30d2bab940] using SAR=1/1
[libx264 @ 0x7f30d2bab940] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x7f30d2bab940] profile High, level 3.1, 4:2:0, 8-bit
[libx264 @ 0x7f30d2bab940] 264 - core 164 r3108 - H.264/MPEG-4 AVC codec - Copyleft 2003-2023 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=22 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, matroska, to 'dummy.mkv':
  Metadata:
    encoder         : Lavf60.16.100
  Stream #0:0: Video: h264 (H264 / 0x34363248), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 25 fps, 1k tbn
    Metadata:
      encoder         : Lavc60.31.102 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
  Stream #0:1: Audio: aac (LC) ([255][0][0][0] / 0x00FF), 44100 Hz, stereo, fltp, 128 kb/s
    Metadata:
      encoder         : Lavc60.31.102 aac
[out#0/matroska @ 0x7f30da3d0580] video:6kB audio:1kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 39.901823%
frame=  125 fps=101 q=-1.0 Lsize=      10kB time=00:00:04.96 bitrate=  16.1kbits/s speed=4.02x
[libx264 @ 0x7f30d2bab940] frame I:1     Avg QP: 9.00  size:   215
[libx264 @ 0x7f30d2bab940] frame P:31    Avg QP: 9.23  size:    46
[libx264 @ 0x7f30d2bab940] frame B:93    Avg QP:12.67  size:    38
[libx264 @ 0x7f30d2bab940] consecutive B-frames:  0.8%  0.0%  0.0% 99.2%
[libx264 @ 0x7f30d2bab940] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x7f30d2bab940] mb P  I16..4:  0.0%  0.0%  0.0%  P16..4:  0.0%  0.0%  0.0%  0.0%  0.0%    skip:100.0%
[libx264 @ 0x7f30d2bab940] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.0%  0.0%  0.0%  direct: 0.0%  skip:100.0%
[libx264 @ 0x7f30d2bab940] 8x8 transform intra:0.0%
[libx264 @ 0x7f30d2bab940] coded y,uvDC,uvAC intra: 0.0% 0.0% 0.0% inter: 0.0% 0.0% 0.0%
[libx264 @ 0x7f30d2bab940] i16 v,h,dc,p: 98%  0%  2%  0%
[libx264 @ 0x7f30d2bab940] i8c dc,h,v,p: 100%  0%  0%  0%
[libx264 @ 0x7f30d2bab940] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x7f30d2bab940] kb/s:8.22
[aac @ 0x7f30d27ff8c0] Qavg: 65536.000

2. Run mkvalidator against video

/mnt/tmp/ # foundation-source/build/mkvalidator/mkvalidator dummy.mkv
..Segmentation fault (core dumped)
/mnt/tmp/ # mkvalidator-0.6.0/build/mkvalidator/mkvalidator dummy.mkv
mkvalidator 0.6.0: the file appears to be valid
        file "dummy.mkv"
        created with Lavf60.16.100 / Lavf60.16.100
Assertion failed: p->Base.Base.RefCount==1 (/mnt/mkvalidator-0.6.0/corec/corec/node/node.c: NodeContext_Done: 2807)
Aborted (core dumped)

gcc version:

/mnt/tmp/ # gcc --version
gcc (Alpine 14.2.0) 14.2.0
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[xlikewise]

Repro files and coredump:
dummy.mkv.zip
core.zip

Backtrace for main @ abcfeae

Reading symbols from ./foundation-source/build/mkvalidator/mkvalidator...
[New LWP 4755]
Core was generated by `./foundation-source/build/mkvalidator/mkvalidator dummy.mkv'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  memcpy () at src/string/x86_64/memcpy.s:22

warning: 22     src/string/x86_64/memcpy.s: No such file or directory
(gdb) bt
#0  memcpy () at src/string/x86_64/memcpy.s:22
#1  0x000055f78901375e in MemRead (p=0x7f40b080f040, Data=0x55f789066390, Size=4, Readed=0x0)
    at /mnt/tmp/foundation-source/corec/corec/helpers/file/memstream.c:34
#2  0x000055f788ff7731 in ReadData (Element=0x7f40b080f820, Input=0x7f40b080f040, ParserContext=0x7fff80a78030,
    AllowDummyElt=1, Scope=1, DepthCheckCRC=0) at /mnt/tmp/foundation-source/libebml2/ebmlbinary.c:35
#3  0x000055f788ffa5b7 in ReadData (Element=0x7f40b0810f10, Input=0x7f40b080f040, ParserContext=0x7fff80a78120,
    AllowDummyElt=1, Scope=1, DepthCheckCRC=1) at /mnt/tmp/foundation-source/libebml2/ebmlmaster.c:310
#4  0x000055f788ffa5b7 in ReadData (Element=0x7f40b0810e10, Input=0x7f40b0810870, ParserContext=0x7fff80a78270,
    AllowDummyElt=1, Scope=1, DepthCheckCRC=2) at /mnt/tmp/foundation-source/libebml2/ebmlmaster.c:310
#5  0x000055f788fe1f52 in main (argc=2, argv=0x7fff80a78d68)
    at /mnt/tmp/foundation-source/mkvalidator/mkvalidator.c:1069

[imajes]

Seeing this also.