Wayland session freeze when playing some videos in mpv

[rotopenguin]

I have some mkv videos with pathologically large (50MB!) coverart pngs attached inside them. If I play one in mpv, the entire desktop becomes unresponsive. By SSHing into my otherwise unresponsive system, I can see that gnome-shell is at 100% cpu load.

This can be reproduced by creating a large png (convert -size 1500x2000 xc: +noise Random noise.png), use mkvtoolnix to open some preexisting mkv file, go to the Attachments tab, add the noise.png file, and "start multiplexing" a new "evil" mkv file. Play that mkv file in mpv. The ~20MB video that this produces should only freeze your desktop for a few seconds.

Doing the same with a dimensionally-large but low-entropy (6000x8000px all white ~20KB) does not appear to cause any issues. Doing it with a 50MB png (3000x3000 should do it) seems to be enough to freeze the desktop for ... as long as I've been willing to wait. Hours.

ProblemType: Bug
DistroRelease: Ubuntu 23.10
Package: gnome-shell 45.1-0ubuntu1
ProcVersionSignature: Ubuntu 6.5.0-14.14-generic 6.5.3
Uname: Linux 6.5.0-14-generic x86_64
ApportVersion: 2.27.0-0ubuntu5
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Fri Dec 15 23:04:21 2023
DisplayManager: gdm3
InstallationDate: Installed on 2023-05-20 (210 days ago)
InstallationMedia: Ubuntu 23.04 "Lunar Lobster" - Release amd64 (20230418)
ProcEnviron:
 LANG=en_US.UTF-8
 PATH=(custom, no username)
 SHELL=/usr/bin/fish
 TERM=xterm-kitty
 XDG_RUNTIME_DIR=<set>
RelatedPackageVersions: mutter-common 45.0-3ubuntu3.1
SourcePackage: gnome-shell
UpgradeStatus: Upgraded to mantic on 2023-10-15 (61 days ago)