KDE Plasma + 7.0.1 issue

Issues & Assistance
1

I’m using a Dell G15 laptop (AMD + NVIDIA) running CachyOS. After updating to kernel 7.0.1, the boot process hangs at a black screen right after the splash logo. Interestingly, this seems to be environment-specific: the LTS kernel (6.18) works fine, and even on kernel 7.0.1, I can launch Hyprland without any issues. The problem only occurs with KDE Plasma. A fresh reinstall didn’t resolve it, though the same kernel/DE combo works perfectly on my desktop. What should be my next steps? Should I provide specific logs or just stick to LTS for now?

2

(guessing from long history) Wait for the next Nvidia update.

3

If so, it would be nice if they fixed this before 7.x becomes LTS in CachyOS :smiley:

4

I’m experiencing the same issue.
Hardware: Lenovo X13 Gen 2 (AMD)
Bootloader: Limine

In my case, I discovered a workaround: after the screen goes black during boot, closing the lid to trigger sleep mode and then reopening it (and pressing the power button) brings up the login screen. This behavior is consistently reproducible in my environment.

5

I’ll try this on my side. Thanks.

6

hmm. i don’t know what’s changed since yday. but today everything works just fine… i noticed different spinner style (three square dots now) + without big cachyos splash logo but in general it looks ok now.

7

Turns out the below didn’t end up being a full fix for me and I am giving up on this path for the moment. Just thought I’d warn you..

Thanks to some AI troubleshooting I’ve identified a possible cause of the black screen / dbus failure.

**Root cause: BPF LSM program `bpf-restrict-fs` blocking /dev/null system-wide**

On linux-cachyos 7.0.x, immediately after switch_root at boot, systemd attaches
a BPF LSM program called `bpf-restrict-fs`. Due to a kernel bug in the 7.0.x s
eries, this program incorrectly denies open() of /dev/null to all processes — i
ncluding root-level system services. You can confirm this is your issue by runn
ing:

journalctl -b | grep "bpf-restrict-fs\\|Permission denied" | head -20

You’ll see `systemd[1]: bpf-restrict-fs: LSM BPF program attached` near the top
, followed by a cascade of Permission denied errors from dbus-broker, polkitd,
and others.

This kills the user D-Bus session → KDE Plasma cannot start → black screen. Dow
ngrading the kernel to 7.0.1 does NOT fix it — both 7.0.1 and 7.0.3 are affecte
d.

Workaround (partial?)

Add `lsm=landlock,lockdown,yama,integrity` to your kernel command line. This re
moves `bpf` from the active LSM list and prevents the broken program from being
attached.

**If you use systemd-boot with sdboot-manage** (default CachyOS setup):

  1. Edit `/etc/sdboot-manage.conf` and update LINUX_OPTIONS to include the param
    eter:

     LINUX_OPTIONS="zswap.enabled=0 nowatchdog quiet splash lsm=landlock,loc

kdown,yama,integrity"

  1. Also edit your boot entry directly so it takes effect immediately on the nex
    t reboot (the conf file only applies when entries are regenerated on kernel upg
    rades):

     sudo nano /boot/loader/entries/linux-cachyos.conf

    Append `lsm=landlock,lockdown,yama,integrity` to the end of the `options` li
    ne.

  2. Reboot normally.

**If you use GRUB:** Add `lsm=landlock,lockdown,yama,integrity` to `GRUB_CMDLIN
E_LINUX` in `/etc/default/grub`, then run `sudo grub-mkconfig -o /boot/grub/gru
b.cfg`.

**Tradeoff:** This disables BPF-based systemd sandbox enforcement (RestrictFile
Systems=). It’s a workaround until the kernel bug is fixed — not a permanent so
lution.

I’ve filed a bug report at linux-cachyos 7.0.x: bpf-restrict-fs LSM BPF program blocks /dev/null system-wide, breaking dbus-broker / KDE login · Issue #838 · CachyOS/linux-cachyos · GitHub . If anyone can re
produce this on a vanilla Linux 7.0.x kernel (not CachyOS-patched), please comm
ent there so we can escalate upstream.

8

thanks. good spot. I’ll check my journalctl today. btw close-open laptop lid also works as a temporary solution.

9

My problem just went away on its own. I had it for exactly one day, and the next day the laptop started up without any problems. Yesterday I updated to 7.0.3 and everything continues to work. So, after all this, I decided to stick with the LTS kernel from now on.