Kernel changes and masking

LIsLinuxIsSogood · Veteran Joined: 13 Feb 2016 Posts: 1175

What resources are available for tracking important changes to the Linux kernel so I can know when it is important to proceed with an upgrade to the kernel?
As of now I sort of just been relying on the maintainers of gentoo's repository to tell me what kernel to be using. I use the gentoo-sources package fyi.
Would it work and still be a good practice to mask kernel source versions greater than or "above" my current one in use so that I can avoid unnecessarily downloading kernel source tree every time it is updated?
I only upgrade the kernel anyway when I have time to go through the manual steps for configuring and installing it, which is probably once a month.

pietinger · Guru Joined: 17 Oct 2006 Posts: 513 Location: Bavaria

I also use gentoo-sources (unstable)

NeddySeagoon · Posted: Sat Sep 05, 2020 11:01 am Post subject:

LIsLinuxIsSogood,

There are two options to consider.

a) you hardware is well supported in the gentoo-sources stable kernel.
Keep using the stable kernel. It gets all the important updates.
When a new stable e.g 4.19.x to 5.4.x comes out, move to it. The .x versions are all important to somebody. You need se read the changelog to decide if you are affected.
It may be faster to update anyway.

b) You have new shiny hardware that does not quite work with the newest kernel you can get plus patches that have not get into the kernel yet.
You need testing gentoo-sources or newer Don't expect improvements every step. Just occasionally things go backward too.

In short, if the stable kernel is good enough, use it but don't mask version mask anything. You will miss things that way.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Tony0945 · Posted: Sat Sep 05, 2020 1:45 pm Post subject:

If running an unstable version, say ACCEPT_KEYWORDS="~amd64" in make.conf, does "sys-kernel/gentoo-sources amd64" in package.accept_keywords do anything? My understanding was that it only unmasked unstable keywords.

NeddySeagoon · Posted: Sat Sep 05, 2020 2:02 pm Post subject:

Tony0945,

You need

Tony0945 · Posted: Sat Sep 05, 2020 2:33 pm Post subject:

LIsLinuxIsSogood · Veteran Joined: 13 Feb 2016 Posts: 1175

So I gather from the last few messages it would be okay and encouraged to use unstable packages for the rest of the system, but stable for kernel? This is counter to what I was generally assuming in terms of mixing stable and experimental branches, but I guess if it is for the kernel specifically it may not be a problem?

pietinger · Guru Joined: 17 Oct 2006 Posts: 513 Location: Bavaria

LIsLinuxIsSogood · Veteran Joined: 13 Feb 2016 Posts: 1175

Well now I am not sure whether or not to downgrade the kernel and if so then how to do so? I tried the scenario of inserting the use flag for sys-kernel/gentoo sources -~amd64 but running the emerge --changed-use or emerge -N does not downgrade automatically. Suggestions?

pietinger · Guru Joined: 17 Oct 2006 Posts: 513 Location: Bavaria

LIsLinuxIsSogood · Veteran Joined: 13 Feb 2016 Posts: 1175

Good point

NeddySeagoon · Posted: Sun Sep 06, 2020 10:09 am Post subject:

LIsLinuxIsSogood,

The mixing branches works both ways A few testing packages on a stable system is the common case. That's the well known package.accept_keywords ~arch
Less common is a few stable packages on an ~arch system. That's package.accept_keywords -~arch.

Its possible that you had the now stable kernel installed in /usr/src before you added

Tony0945 · Posted: Sun Sep 06, 2020 3:04 pm Post subject:

LIsLinuxIsSogood · Veteran Joined: 13 Feb 2016 Posts: 1175

I am currently using an unstable kernel, 5.8.3, and I do want to avoid updating the kernel as often as it seems the latest unstable sources are "pushed" in the repo -- that process being tedious and time consuming. SO, I've made the accept_keyword change and downloaded the lower version of kernel 5.4.60. I am considering the downgrade just so I can keep up with the latest stable kernel version, but I could also keep running 5.8.3. However it is conceivable that 5.4.60 as a stable kernel is safer and more reliable than staying with this later kernel version that in its x.x.3 revision as opposed to the x.x.60 for the 5.4 would end up becoming outdated quickly putting me back in the same position I am now of upgrading again and again. I bet by the time 5.8 is available as stable it would be far beyond 5.8.3 so I guess I should not risk keeping 5.8.3 and downgrade to 5.4.60.

asturm · Posted: Mon Sep 07, 2020 9:32 am Post subject:

Only LTS kernels are stabilised so 5.8 will never be stable. But if it works for you now, why change? By now there's already 5.8.7 available which by definition has received numerous fixes over 5.8.3.
_________________
backend.cpp:92:2: warning: #warning TODO - this error message is about as useful as a cooling unit in the arctic

DespLock · n00b Joined: 27 Jul 2020 Posts: 46

Another way to do this: emerge a special kernel version:
emerge --noreplace sys-kernel/gentoo-sources:5.8.3

Then remove gentoo-sources from world (file):
emerge --deselect gentoo-sources
emerge --depclean

After that you can install newer versions like above.

NeddySeagoon · Posted: Mon Sep 07, 2020 10:03 am Post subject:

LIsLinuxIsSogood,

Once 5.9.x is out, there will be no more changes to 5.8.
Either track LTS or testing but don't stay on 5.8 now with the intent to track LTS 'one day'.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Tony0945 · Posted: Mon Sep 07, 2020 3:48 pm Post subject:

NeddySeagoon · Posted: Mon Sep 07, 2020 4:49 pm Post subject:

Tony0945,

Yes. The problem is that LIsLinuxIsSogood will stay on gentoo-sources-5.8.3 long after its forgotten, until there is a newer LTS kernel.
gentoo-sources-5.8.3 is already forgotten. 5.8.7 is out.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

pietinger · Guru Joined: 17 Oct 2006 Posts: 513 Location: Bavaria

LIsLinuxIsSogood,

you want to avoid too many updates of your kernel. You can do this with a stable (today: 5.4.x) and an unstable kernel (today: 5.8.7), BUT ...

... dont believe a stable kernel has less updates than the unstable ones (think of 5.4.60 - in words: sixty). This is because every bug found in newer unstable kernels wil be BACKPORTED to the actual LTS-kernel. And for security reasons you should update your stable LTS-kernel ALSO when a new version is out ...

so, you dont win (or loose) something with your decission for a stable kernel.

Tony0945 · Posted: Mon Sep 07, 2020 5:16 pm Post subject:

pietinger,

What you win is avoiding the weekly build of a new kernel.

pietinger · Guru Joined: 17 Oct 2006 Posts: 513 Location: Bavaria

LIsLinuxIsSogood · Veteran Joined: 13 Feb 2016 Posts: 1175

Not to deter from discussions about stable vs unstable, but now that I downgraded the kernel, and I decided I want to keep the latest version in my /boot folder since I know it works. When running grub-mkconfig I believe the default entry is set to the highest version number of the kernel found, which unfortunately is not the one I want. I would read all the grub documentation to figure it out myself, but I am also not one to shy away from recommended solutions. So what is a way to instruct grub to either remove or block the 5.8.3 kernel or else to prioritize the lower kernels in the boot loader's menu entry order? thank you in advance for your suggestions.

Tony0945 · Posted: Thu Sep 10, 2020 1:38 pm Post subject:

LIsLinuxIsSogood,

If you were running rEFInd, all you would have to do is run "touch <full pathname of desired boot kernel>" and it would become the latest. I suppose you could do that with grub:2 also, running your grub command afterward.

Tony0945 · Posted: Thu Sep 10, 2020 1:47 pm Post subject: