Split tunneling not supported due to no cgroup v2 support?

[shygram]

Is it a bug?

• I know this is an issue with the app, and contacting Mullvad support is not relevant.

I have checked if others have reported this already

• I have checked the issue tracker to see if others have reported similar issues.

Current Behavior

I am unable to split tunnel, everything is grayed out and mullvad vpn gui thinks my kernel doesnt support cgroups v2

Expected Behavior

Split tunneling just works

Steps to Reproduce

1. Boot Mullvad VPN GUI
2. Go to Split Tunneling
3. Split tunneling is not supported by your system. Click here to learn more, so I click there.
4. "To use Split tunneling, please update to a Linux kernel version that supports cgroup v2."

Failure Logs

[2026-06-08 20:56:12.651][verbose] Chromium sandbox is enabled
[2026-06-08 20:56:12.652][info] Running version 2026.2
[2026-06-08 20:56:13.014][info] Detected locale: en-US
[2026-06-08 20:56:13.263][info] Verified socket ownership
[2026-06-08 20:56:13.263][info] Connected to the daemon
[2026-06-08 20:56:13.359][info] Skip autoconnect because GUI setting is disabled
[2026-06-08 21:56:14.569][verbose] GRPC Channel connectivity state changed to 2
[2026-06-08 22:56:14.570][verbose] GRPC Channel connectivity state changed to 2
[2026-06-08 23:56:14.571][verbose] GRPC Channel connectivity state changed to 2
[2026-06-09 00:56:14.572][verbose] GRPC Channel connectivity state changed to 2
[2026-06-09 01:56:14.573][verbose] GRPC Channel connectivity state changed to 2
[2026-06-09 02:16:58.441][error] Failed to load nativeImage: /usr/share/pixmaps/python3.xpm
[2026-06-09 02:16:58.587][error] Failed to load nativeImage: /usr/share/pixmaps/gxkb.xpm
[2026-06-09 02:30:11.339][error] Failed to load nativeImage: /usr/share/pixmaps/python3.xpm
[2026-06-09 02:30:11.488][error] Failed to load nativeImage: /usr/share/pixmaps/gxkb.xpm
[2026-06-09 02:47:31.658][info] Disconnected the tunnel
[2026-06-09 02:47:31.658][info] before-quit received
[2026-06-09 02:47:31.658][info] Quit initiated
[2026-06-09 02:47:31.659][info] Unsubscribed from the daemon events
[2026-06-09 02:47:31.660][verbose] GRPC Channel connectivity state changed to 4

Operating system version

MX Linux 25.2 (Debian 13.5)

Mullvad VPN app version

2026.2

Additional Information

Kernel version: Linux 6.12.90+deb13.1-amd64

Recently I did a distrohop from Slackware to MX Linux on my desktop computer. On Slackware, I was using the last 2025 release of the mullvad vpn gui. In that version, I could still split tunnel, but I'd have to use the following commands for it to work:

mkdir -p /sys/fs/cgroup/net_cls/mullvad-exclusions/
touch /sys/fs/cgroup/net_cls/mullvad-exclusions/cgroup.procs
chmod 777 /sys/fs/cgroup/net_cls/mullvad-exclusions/cgroup.procs

This was not ideal, but it was at least something. Now in the new 2026 GUI on Debian, nothing works. Instead, everything is grayed out and I get "Split tunneling is not supported by your system. Click here to learn more" and when I click there I get "To use Split tunneling, please update to a Linux kernel version that supports cgroup v2.".

This perplexed me at first considering v2 cgroups have apparently been a thing in the linux kernel for about a decade at this point, but then I noticed some projects (including this one) only recently started migrating to it. My guess is v1 was deprecated in this release and maybe MX's kernel is nonstandard in a way that doesnt support v2 cgroups (I believe that is a vanilla debian kernel though)? Maybe it has something to do with not using systemd by default since I've seen cgroups mentioned with systemd before, but I really don't know and I just want to be able to use split tunneling again since I've had it work with Debian before and even Slackware not that long ago. I'm totally lost at this point.

[hulthe]

"To use Split tunneling, please update to a Linux kernel version that supports cgroup v2."

The error message was updated prematurely, as we haven't finished the migration to v2 yet. It's supposed to say that you need cgroups v1. (#10564)

Sorry for the confusion :)

mkdir -p /sys/fs/cgroup/net_cls/mullvad-exclusions/
touch /sys/fs/cgroup/net_cls/mullvad-exclusions/cgroup.procs
chmod 777 /sys/fs/cgroup/net_cls/mullvad-exclusions/cgroup.procs

Have you tried if these steps work on MX Linux?

[shygram]

I actually wasn't aware of this, but unfortunately I'm still lost. For starters, no the mkdir, touch and chmod commands I mentioned using on Slackware didn't work on MX Linux either, otherwise I wouldn't have even made this post. Also, when I looked up cgroup v1 on the MX forums, I found this post: https://forum.mxlinux.org/viewtopic.php?p=829558&hilit=cgroup+v1#p829558

"NOTE: This project was broken by a change in the 6.12 kernel that turns off cgroup v1 support by default.
Therefore, this project is effectively retired."

Sure enough when I went to the systemd-shim github link on that page, the note is there too. So now I know my kernel version doesn't support v1 cgroups, and because mullvad vpn's gui actually does still depend on v1 cgroups, logically this means I really do need to be using a different kernel, right?

Unfortunately, it still isn't so simple. I tried kernels 6.6, 5.10, and even a 6.19 liquorix kernel since I found out from a little snippet in the antiX forums that the new liquorix kernels should still support cgroup v1. https://www.antixforum.com/forums/reply/183086/

"the change turned out to be debian disabling cgroup v1 in the kernel. liquorix kernels still have it enabled, for now."

NONE of these solutions worked for me, I still get the same old error. At this point I'm wondering if I'm missing something else entirely or if I need to build my own kernel at this point. I installed cgroup-tools and libcgroup3 thinking maybe I just needed packages from the repo this whole time, but that did nothing at all. I'm back at square 1.