Ignore ZRAM devices in the Qubes Devices tray menu

[Atrate]

How to file a helpful issue

Qubes OS release

4.2.1

Brief summary

AppVMs' zram devices show up in the Qubes Devices tray menu. Accidentally assigning them to an AppVM and then unassigning causes a lockup of most Qubes functionality (no new VMs can be launched, shut down, etc.).

Steps to reproduce

1. Install zram-generator in a qube template (e.g. F39).

2. Configure zram, for example like this:

[zram0]
zram-size = ram * 10
compression-algorithm = lz4
swap-priority = 200
fs-type = swap

(Note: I use ram * 10 because zram-generator takes the amount of ram that it sees as the maximum at qube startup, this is usually around 800MB on my system, so it results in around 8GB of zram being created.)

3. Shut the template down, boot a qube from that template (may need to reboot QubesOS first)

4. Click on the Qubes Devices tray menu, assign a zram device (called () in the menu) to a qube (I tried the same qube itself).

5. Unassign that zram device.

Expected behavior

Zram devices shouldn't show up in the tray menu. If they do, it shouldn't break QubesOS to assign/unassign them.

Actual behavior

Qubes Devices tray stops functioning, can't boot any new domains, can't shut any domains down, can't open Qube Manager, probably many other things I haven't tried. Shutting the OS down also takes a lot longer because of having to wait on unit timeouts.

[DemiMarie]

Wow, this is pretty bad. I can understand that assigning them would break things, but this should not break the whole system!