Issues with 5.18.18 kernel on Fedora 36

I am having some major issues with the latest 5.18.18-200 kernel on Fedora 36.

First of all, it boots into the emergency mode because the grub entry is missing “ro rootflags=subvol=@” entry. If I manually add that in in the grub menu during boot, or if I use grubby to add it permanently, then everything loads, but the system is really slow and is stuttering heavily, even just moving the mouse around.

Everything works fine on 5.18.17-200.

Any idea what is going on? I removed 5.18.18 once and let the update install again and had exactly the same issue. I also removed the akmod-nvidia drivers and reinstalled them, but it made no difference.

Is 5.18.18 just bugged, or am I doing something wrong?

I think I saw a bunch of wayland related processes running and using CPU, which doesn’t happen on 5.18.17 for me. Maybe the nVidia driver wasn’t really working right? Either way, why did I need to mess with the args in grub?

Sorry, relatively new to Linux.

Thank you.

It’s a probably this bug, 2118287 – Updating kernel arguments with grubby --update-kernel=ALL results in kernel not booting after kernel upgrade

Can you check:
sudo grubby --info=ALL
cat /etc/kernel/cmdline


If it is that bug, I believe you can recover by.
Falling back to 5.18.17, re-install nvidia drivers, remove /etc/kernel/cmdline, and re-installing 5.18.18.



Thank you for your reply!
Removing the cmdline file and reinstalling the 5.18.18-200 fixed the grub issue. It correctly generated the arguments to include “ro rootflags=subvol=@”.

So what and why created this cmdline file? It’s not there after the reboot. So should it not exist? If so, why was it there? Just trying to learn/undertsand Linux better.

As a side note, it is still stuttering on 5.18.18…htop shows over a dozed wayland processes running each consuming ~9% CPU. So something is bugged. Possibly with the current nVidia driver?

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You probably need to reinstall the nvidia drivers in 5.18.18, especially if it works fine in 5.18.17.

There’s additional discussion regarding what is happening under this bug; 2113883 – grub2-mkconfig -o /boot/grub2.cfg doesn't update pre-installed kernel cmdline after changing GRUB_CMDLINE_LINUX

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Yep. Looks like reinstalling the drivers fixed it. Mostly because it takes some time to boot up the first time after the driver install, and I thought it hanged last time and forcefully rebooted without letting it finish whatever it was actually doing. :grimacing: I guess I am learning!

Thank you for the links to the bug discussions too!


A simple trick I have learned when the kernel or nvidia has an update is to open system monitor and watch the cpu usage.While the drivers are building with the new kernel the usage will be very high for a few minutes.When the usage settles back down to normal then reboot.

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I do not have an nvidea gpu so no drivers installed. But I had the same issue and removing /etc/kernel/cmdline did the trick :grin: