Lubuntu 22.04.2 LTS Upgrades still using the 5.15 GA kernel

[Surepic]

Doing full system upgrade doesnt upgrade your kernel to the latest 5.19 version.
After applying full system upgrade:
To know which kernel version you are running:

your@comp:~$ uname -r
5.15.0-60-generic

Check if you are on 22.04.2:

your@comp:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 22.04.2 LTS
Release:        22.04
Codename:       jammy

To check if your are on HWE or GA kernel:

your@comp:~$ hwe-support-status --verbose
You are not running a system with a Hardware Enablement Stack. Your system is supported until April 2027.

As you see I`m on release 22.04.2 but with kernel 5.15 (i.e. GA not HWE).
To switch from GA to HWE kernel check on what it depends:

your@comp:~$ sudo apt-cache depends linux-image-generic-hwe-22.04
linux-image-generic-hwe-22.04
  Depends: linux-image-5.19.0-32-generic
  Depends: linux-modules-extra-5.19.0-32-generic
  Depends: linux-firmware
  Depends: intel-microcode
  Depends: amd64-microcode
  Recommends: thermald

Now upgrade to new kernel:

your@comp:~$ sudo apt install linux-generic-hwe-22.04

After its done reboot.

Congratulations now you are on latest kernel!

[guiverc]

Lubuntu is a flavor of Ubuntu, as such the installation media dictates the default kernel stack used.

It’s expected that as Lubuntu users upgrade from 22.04.1 to 22.04.2 they may or may-not change kernels, as their installation media (either on 22.04, or earlier if it was a 20.04 install for example) set what packages were installed (ie. GA or HWE kernel stack), and its those packages that control if HWE kernel stack is used (ie. the 5.19 kernel from 22.10 at 22.04.2) or GA kernel stack (ie. remain on 5.15 for the life of 22.04).

Lubuntu (and other flavors) follow the standard that was used by Ubuntu Desktop up to (and including) the 18.04 release, ie. 18.04/20.04/22.04 & 18.04.1/20.04.1/22.04.1 installation media will have the install using the GA kernel stack, however 18.04.2/20.04.2/22.04.2 & later will have the install using the HWE kernel stack for the given release.

Both GA & HWE stacks are supported the life of the product, but which you’re using depends on your installation media for flavors like Lubuntu.

Ubuntu 20.04 LTS Desktop changed this and defaults to using the HWE kernel stack for all media, but flavors did not change that way. The reason for Ubuntu Desktop’s change was that desktop hardware is often newer & can thus benefit from the newer kernel stack support (esp. for video hardware). Ubuntu 20.04 LTS Server still defaults to the more stable GA kernel stack as stability is valued on servers.

The wiki page with this detail is Kernel/LTSEnablementStack - Ubuntu Wiki though flavors aren’t specifically mentioned on that page. (I’ve thought about adding that flavor specifics to that page, but haven’t been sure about the best wording, thus never have & it talks only about Ubuntu Desktop & Server).

Also FYI: You can have both GA & HWE kernel stacks installed on your system; I do on many of my LTS releases so I’m aware of when different kernels change, though also note many closed-source proprietary kernel modules (eg. some Nvidia video drivers) can prevent both stacks co-existing on the same install.

[Surepic]

My post was to clear up confusion that some users might get after reading announcement thread about 22.04.2 particularly as there are users whose native language is not english.

“
This Lubuntu 22.04.2 media also contains the updated HWE 5.19 kernel stack (from Lubuntu 22.10) where prior 22.04 media contained only the 5.15 GA kernel stack.
“

I wanted to pinpoint the fact that even tho after full upgrade via settings->full upgrade and rechecking via lsb_release -a some might think that their kernel version is also upgraded but in fact it isnt.

[Bartman]

I prefer the long term stable (LTS) 5.15 GA kernel over the short term HWE 5.19 kernel using my old outdated computers.

Newer kernels seem to offer a possibility of problems from my experience which is why I prefer LTS kernels over HWE kernels.

Could be because of using old outdated computers pieced together from many other old computers…

[Surepic]

On my old amd9200e with 8gb ram after upgrading to new kernel got performance increase of 17%! Changelog of kernel from 5.15 to 5.19 is pretty excessive so would recommend to try on old hardware and confirm. Oh and performance difference i obtained via xmrig miner compiled from source code on my machine in test mode. This one uses cpu and ram very excessively.

[guiverc]

I agree with @Bartman actually; in that older GA kernels in my experience work better on older hardware.

Until my old primary PCs PSU gave out ~Oct 2022, my primary PC was a 2009 dell desktop… That had me use a replacement (older box) for a few months, until I somewhat recently got a new (second-hand) box. My QA boxes are older than my old-primary PC was (for the most part anyway).

HOWEVER, each PC is unique, with different CPU, different chipsets, different speed RAM, etc…, so any general statement such as “old hardware, use older kernel stack” will always be proved wrong with some hardware. Yes we need to try things out, and live media allows us to somewhat easily do this, without re-install too.

Well done @Surepic for reading the kernel changelogs ! That will give you a really good insight; impressive!

[user8446]

Hi, how would I go back to 5.15 if 5.19 is buggy?

[ArrayBolt3]

It’s kind of tricky, but the basic idea is:

1. Install linux-generic.
2. Remove linux-generic-hwe-22.04 and then do an apt autoremove.
3. Uninstall all the other kernels.
4. Profit.

To start, just run sudo apt update && sudo apt install linux-generic && sudo apt remove linux-generic-hwe-22.0 && sudo apt autoremove and that will do steps 1 and 2. Step 3 is a bit harder though.

Each kernel consists of four components - linux-image-VERSION-generic, linux-modules-VERSION-generic, linux-modules-extra-VERSION-generic, and linux-headers-VERSION-generic. The VERSION is different for each installed kernel - if you run ls /boot, you’ll see files like vmlinuz-5.19.0-29-generic - the “5.19.0-29” is the version.

So if you want to remove a kernel, you’d run:

sudo apt remove linux-image-VERSION-generic linux-modules-VERSION-generic linux-modules-extra-VERSION-generic linux-headers-VERSION-generic

replacing VERSION with the version number. For instance, to remove kernel 5.19.0-29, you’d run sudo apt remove linux-image-5.19.0-29-generic linux-modules-5.19.0-29-generic linux-modules-extra-5.19.0-29-generic linux-headers-5.19.0-29-generic and the kernel would be uninstalled.

So in order to go back to the older kernel, you want to remove all the kernels except for the 5.15 one that you installed when you ran sudo apt install linux-generic. To do that, just run ls /boot and look at all of the kernels you have. For each kernel who’s version does not start with “5.15”, run the kernel uninstallation command, replacing all four VERSIONs with the kernel version you’re removing. You want to be left with a single 5.15 kernel when you’re done.

Be careful, if you get carried away and accidentally uninstall all kernels, that would be bad.

The system will probably throw a small tantrum when you try to uninstall the kernel that you’re actively booted into - as long as you’ve installed the linux-generic package first and still have a 5.15 kernel on the system at that point, you can safely tell the system to go ahead and remove the kernel even though you’re running it. (No, this will not cause a system crash like you might imagine - the kernel is fully loaded into RAM and the system should continue to run just fine once you remove it from the disk, until you reboot. You just need to make sure you have a kernel available to boot into once you reboot.)

If all goes well, you should be running 5.15 by the end of it - you can run uname -r in a terminal to confirm this.

[guiverc]

You can read the instructions from the link I provided previously

https://wiki.ubuntu.com/Kernel/LTSEnablementStack

Look for “To downgrade from HWE/OEM to GA kernel:”

You may also note the instructions tell you to install the GA kernel stack first, then test the system (ie. both stacks are installed!*).

Then it mentions “If everything is good, you may remove the other kernel flavours:”, ie. the removal of the HWE stack is optional, as both stacks can co-exist, unless you’re using nvidia or other closed-source proprietary kernel modules…

The document uses 20.04 as it’s guide, but change 20.04 to 22.04 or as @Arraybolt3 has suggested… My point is, don’t be in a hurry to remove the HWE kernels if you don’t want to, they can co-exist on an install, allowing you to select at grub during boot which you’ll use & return to 5.19 to quickly test to see if issues get resolved.

[user8446]

Thank you @ArrayBolt3 @guiverc!