Opened 3 years ago

Last modified 8 months ago

#6364 open defect

ffmpeg is triggering an assertion and the assertion is causing a malloc corruption

Reported by: crow Owned by:
Priority: important Component: undetermined
Version: git-master Keywords: vdpau crash regression
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no

Description

Summary of the bug: it looks like ffmpeg is triggering an assertion (which it shouldn't) and the assertion is causing a malloc corruption. The malloc corruption probably isn't a bug in ffmpeg (but in libc), but the assertion triggering seems like a probable bug in ffmpeg.
This above was written by "c_14" on IRC!

The backtrace could be found in the attachment.

This isn't happening with the ffmpeg 3.2.4 .

How to reproduce: with using VDR and its vdr-softhdevice output plugin with Live TV. I'll try to provide recording of this Live TV channel with the ffmpeg 3.2.4 and provide it here.

% ffmpeg -i input ... output
ffmpeg version 3.3
built on Archlinux x86_64 with glibc 2.25

Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.

Attachments (1)

ffmpeg_3.3_crash01.txt (128.9 KB) - added by crow 3 years ago.
backtrace from crash

Download all attachments as: .zip

Change History (11)

Changed 3 years ago by crow

backtrace from crash

comment:1 Changed 3 years ago by Cigaes

It is hard to say who is responsible for what here. A few issues are yet obvious:

  • the libc is calling i18n functions from an assert failure handler, that is just stupid;
  • the crashing code is using assert() instead of av_assert0().

Now, neither of these is the cause of the bug itself. There are two possibilities:

  • either this is really a bug in FFmpeg;
  • or vdr is somehow corrupting the memory, and that later triggers the assertion failure.

Anyway, it is not a part of the code that I know.

comment:2 Changed 3 years ago by cehoyos

  • Keywords vdpau regression added; backtrace coredump glibc removed
  • Priority changed from normal to important
  • Version changed from unspecified to git-master

Please run a bisect to find out which change triggers the regression.

comment:3 Changed 3 years ago by crow

I tried bisect but there were two commits which could not be build here so i skip them. Please not that compile of 12 commits were successful so I can only guess it is not the build system.

bisect
good n3.2.4
bad n3.3 and current master as of today

$ git bisect reset
We are not bisecting.
$ git bisect start
$ git bisect good d4b731e271ba944ade8f6a128271479529507de9
$ git bisect bad 1968a1eef1cae22e162259d7082c2eea98d81e32
Bisecting: 930 revisions left to test after this (roughly 10 steps)
[928db5134478b4a410d9256a4d56cd8a7d4989b9] Merge commit '27085d1b47c3741cc0fac284c916127c4066d049'
$
$ git bisect skip
There are only 'skip'ped commits left to test.
The first bad commit could be any of:
38efff92f1ef81f3de20ff0460ec7b70c253d714
4a9bab3db0d9ec449ebc8b5e823374d1d1df7761
744801989099df26e90b00062c645969c5347533
We cannot bisect more!
$

Why this commits were skipped:

38efff92f1ef81f3de20ff0460ec7b70c253d714
4a9bab3db0d9ec449ebc8b5e823374d1d1df776164

is because i needed to exclude almost half of stuff from ./configure and then again there were such compile errors

Unknown option(s)

--disable-stripping \
--enable-fontconfig \
etc etc.
HOSTCC  doc/print_options.o
In file included from doc/print_options.c:32:0:
./libavcodec/options_table.h:87:1: warning: ‘me_method’ is deprecated [-Wdeprecated-declarations]
 {"me_method", "set motion estimation method", OFFSET(me_method), AV_OPT_TYPE_INT, {.i64 = ME_EPZS }, INT_MIN, INT_MAX, V|E, "me_metho
d"},
 ^
In file included from ./libavformat/avformat.h:258:0,
                 from doc/print_options.c:29:
./libavcodec/avcodec.h:1627:30: note: declared here
     attribute_deprecated int me_method;
                              ^~~~~~~~~
...
...
In file included from ./libavformat/avformat.h:258:0,
                 from doc/print_options.c:29:
./libavcodec/avcodec.h:3035:9: note: declared here
     int side_data_only_packets;
         ^~~~~~~~~~~~~~~~~~~~~~
HOSTLD  doc/print_options
GENTEXI doc/avoptions_format.texi
GENTEXI doc/avoptions_codec.texi
POD     doc/avconv.pod
MAN     doc/avconv.1
POD     doc/avprobe.pod
MAN     doc/avprobe.1
CC      tools/qt-faststart.o
LD      tools/qt-faststart
make: *** No rule to make target 'doc/ffmpeg.1'.  Stop.
==> ERROR: A failure occurred in build().
    Aborting...
==> ERROR: Build failed

comment:4 Changed 3 years ago by crow

I was able to compile one skiped commit by disabling building of docs (thanks BtbN from IRC), and marked that as good and got:

744801989099df26e90b00062c645969c5347533 is the first bad commit

http://git.ffmpeg.org/gitweb/ffmpeg.git/commit/744801989099df26e90b00062c645969c5347533

Last edited 3 years ago by crow (previous) (diff)

comment:5 Changed 3 years ago by cehoyos

  • Status changed from new to open

comment:6 Changed 3 years ago by crow

Is something else needed from me regarding this bug report? Below you can find ffprobe from recording which was taken with VDR (vdr-sotfhddevice compiled against ffmpeg 3.2.4) which can be replayed just fine, but replay fails and crash with VDR (vdr-softhddevice compiled against ffmpeg 3.3.)

ffprobe

$ ffprobe -i /srv/vdr/video/test/2017-05-04.19.45.16-0.rec/00001.ts
ffprobe version 3.3 Copyright (c) 2007-2017 the FFmpeg developers
  built with gcc 6.3.1 (GCC) 20170306
  configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-avisynth --enable-avresample --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libass --enable-libbluray --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxvid --enable-netcdf --enable-shared --enable-version3
  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
[h264 @ 0x55cae0d8f6e0] mmco: unref short failure
    Last message repeated 1 times
[mpegts @ 0x55cae0d8ac40] PES packet size mismatch
    Last message repeated 1 times
Input #0, mpegts, from '/srv/vdr/video/test/2017-05-04.19.45.16-0.rec/00001.ts':
  Duration: 00:00:58.65, start: 71545.302244, bitrate: 3101 kb/s
  Program 132
    Stream #0:0[0x6ff]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(tv, bt470bg, top first), 720x576 [SAR 16:11 DAR 20:11], 24.92 fps, 25 tbr, 90k tbn, 50 tbc
    Stream #0:1[0x700](qae): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 192 kb/s
    Stream #0:2[0x701](qaf): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 192 kb/s
$

comment:7 Changed 3 years ago by crow

same problem also with ffmpeg 3.3.1

comment:8 Changed 3 years ago by heleppkes

You should try to reproduce the problem without any external software, but only with ffmpeg, and then share a sample file that triggers the problem. Debugging problems that require external software to occur complicates the entire process.

Version 0, edited 3 years ago by heleppkes (next)

comment:9 Changed 3 years ago by crow

@heleppkes
Can you give me an example how to test directly by using ffmpeg? Here I have an .ts recording, but I am unable to find right examples how to play this file with ffmpeg directly on my TV (Xorg running).

I'll pass this info regarding deprecated vdpau code to the vdr-softhddevice (output plugin for VDR) developer.

comment:10 Changed 8 months ago by Balling

Can we close this?

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