Crashes with "double free" or "invalid chunk size" with some mp4 files

[Jani Uusitalo]

I'm seeing memory-related crashes when playing videos sliced (with ffmpeg -c copy) from mp4 streams (downloaded with youtube-dl). I'm attaching a sample clip which, granted, is pretty useless for a video, but which produces these crashes with 100% certainty for me; I just edited it down to a reasonable size and non-infringing content.

The errors reported just before core is dumped are (mostly) "double free or corruption (fasttop)" or (less often) "malloc_consolidate(): invalid chunk size".

To be clear, my expectation here is not for the problematic clips to have useful content, or even to play back; just that vlc didn't crash. (Totem for instance does not seem to crash with the same files.)

I'll attach logs for both the double free and malloc_consolidate cases (which I'm producing by running LC_ALL=C vlc -vvv out.mp4 in a loop).

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: vlc 3.0.3-1-1ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-36.39-generic 4.15.18
Uname: Linux 4.15.0-36-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sat Oct 20 18:14:25 2018
InstallationDate: Installed on 2016-10-13 (737 days ago)
InstallationMedia: Ubuntu-Server 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=fi_FI.UTF-8
 SHELL=/bin/bash
SourcePackage: vlc
UpgradeStatus: No upgrade log present (probably fresh install)

[Sebastian Ramacher (s-ramacher)]

This issue is also present in vlc 3.0.7, but not in the 4.0 branch.

[Jani Uusitalo (uusijani)]

Seems to be fixed in VLC 3.0.9.2-1 (Ubuntu 20.04); at least I haven't been able to reproduce it anymore.