Rapidly increasing memory usage of kwin_x11 while watching videos

[Alex B]

A few days ago, I upgraded from Ubuntu 19 to Ubuntu 20. Ever since then, whenever I watch a video (Youtube and Netflix in both Firefox and Chrome, people streaming their webcams in GoToMeeting in Chrome, etc), the resident memory usage of kwin_x11 climbs up at a rate of about 100MB per 5-10 seconds to the point where it takes all the ram and swap (see screenshot attached, though it goes even higher). When it has filled my ram and swap, it just stops increasing. Then, if I open a new window of whatever app (or perform some other action on the desktop), I will get a lag and memory usage will drop down to almost nothing. Letting the video play will result in memory usage increasing in the same fashion again and again.

I'm not sure if it's related, but I'm also seeing some segfaults in dmesg, but I was unable to correlate the timing of the segfault with high memory usage so far:

[ 1663.034397] SGI_video_sync[9193]: segfault at e6 ip 00005639903c9bfd sp 00007f9988a627c0 error 6 in bitwarden[56398cfb8000+5322000]
[ 1663.034406] Code: 0f 46 d8 89 df e8 43 00 00 00 4c 89 f7 e8 db 01 00 00 41 8b 46 10 41 8b 4e 18 0f b6 c0 c1 e0 0c 0f b6 c9 c1 e1 14 09 c1 09 d9 <c6> 01 00 81 e3 ff 0f 00 00 c6 03 00 bf 01 00 00 00 e8 bd b3 f0 01
[ 1663.692678] SGI_video_sync[9212]: segfault at e6 ip 0000557c749aebfd sp 00007fd08c8157c0 error 6 in bitwarden[557c7159d000+5322000]
[ 1663.692686] Code: 0f 46 d8 89 df e8 43 00 00 00 4c 89 f7 e8 db 01 00 00 41 8b 46 10 41 8b 4e 18 0f b6 c0 c1 e0 0c 0f b6 c9 c1 e1 14 09 c1 09 d9 <c6> 01 00 81 e3 ff 0f 00 00 c6 03 00 bf 01 00 00 00 e8 bd b3 f0 01
[ 1664.212728] SGI_video_sync[9223]: segfault at e6 ip 000055c73953cbfd sp 00007f62d88a47c0 error 6 in bitwarden[55c73612b000+5322000]
[ 1664.212737] Code: 0f 46 d8 89 df e8 43 00 00 00 4c 89 f7 e8 db 01 00 00 41 8b 46 10 41 8b 4e 18 0f b6 c0 c1 e0 0c 0f b6 c9 c1 e1 14 09 c1 09 d9 <c6> 01 00 81 e3 ff 0f 00 00 c6 03 00 bf 01 00 00 00 e8 bd b3 f0 01

xorg 1:7.7+19ubuntu14
nvidia 440.100-0ubuntu0.20.04.1
kwin-x11 4:5.18.5-0ubuntu0.1

Don't hesitate if you need more info. Thanks!

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: kwin-x11 4:5.18.5-0ubuntu0.1
ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44
Uname: Linux 5.4.0-42-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.8
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Fri Aug 21 15:26:52 2020
ExecutablePath: /usr/bin/kwin_x11
InstallationDate: Installed on 2019-06-20 (428 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
ProcEnviron:
 LANGUAGE=en_CA:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_CA.UTF-8
 SHELL=/bin/bash
SourcePackage: kwin
UpgradeStatus: Upgraded to focal on 2020-08-18 (2 days ago)

[Scarlett Gately Moore (scarlettmoore)]

This bug is very old, if it is still an issue please update the bug with information from a supported release.

[Launchpad Janitor (janitor)]

[Expired for kwin (Ubuntu) because there has been no activity for 60 days.]