[SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

GhettoGirl · 2016-06-08 12:03:37

Today pacman offered me to upgrade my Kernel to 4.6.1
The last time I tried that kernel on another distro, I wasn't able to boot anymore, because of a bug Linux wasn't able to find any HDDs or SSDs and timed out waiting for root filesystem.
I'm a bit afraid now to upgrade. Can I downgrade the kernel using the bootstrap (installer) in case something wents wrong?

If this is not the case, I already know how to ignore updates with pacman in /etc/pacman.conf

Regards

Last edited by GhettoGirl (2016-06-09 12:48:22)

mis · 2016-06-08 12:20:28

You could install linux-lts before upgrading.
Then you should be able to boot with the lts kernel if 4.6.1 does not work for you.

Arup · 2016-06-08 12:30:23

No issues here, i7 4790 with nvidia 610 using nvidia drivers. Big thing is that finally the i7 Haswell scale again.

GhettoGirl · 2016-06-08 13:34:04

ok, i will install the linux-lts kernel before upgrading to 4.6.1
anyway to go back to 4.5.4 in case 4.6.1 ends up waiting for root device?
can i "backup" or "dump" a installed pacman package?

graysky · 2016-06-08 13:46:11

Your package cache is /var/cache/pacman/pkg and all packages you installed (prev or current) are there... note that it is a bad idea to run old kernels as they are not supported upstream. Also note that partial updates are not officially supported. If the 4.6 series doesn't work for you, work with upstream to fix it. If you want to run the 4.5 series, I recommend that you build your own (use ABS) and keep it updated (current stable is 4.5.7 according to https://www.kernel.org but that will go EOL at some point).

ewaller · 2016-06-08 14:08:52

The answer to your question is yes, you can downgrade if things go awry. You can boot from your install media, set up a chroot, and downgrade using the pacman cache on your system. I think you will be okay with the 4.6.1 kernel, but you can go back.

Arup · 2016-06-08 14:11:58

Rather than use old kernel, I would strongly recommend using LTS one for backup.

Arup · 2016-06-08 14:12:56

graysky wrote:

Your package cache is /var/cache/pacman/pkg and all packages you installed (prev or current) are there... note that it is a bad idea to run old kernels as they are not supported upstream. Also note that partial updates are not officially supported. If the 4.6 series doesn't work for you, work with upstream to fix it. If you want to run the 4.5 series, I recommend that you build your own (use ABS) and keep it updated (current stable is 4.5.7 according to https://www.kernel.org but that will go EOL at some point).

By the way, the CPU scaling issue with Haswell refresh is gone with 4.6, in fact now its scaling better than Ubuntu's 4.4 250MHz kernel.

ewaller · 2016-06-08 14:13:23

Arup wrote:

Rather than use old kernel, I would strongly recommend using LTS one for backup.

I might add, one can also install an alternate kernel from inside the chroot instead of downgrading,

GhettoGirl · 2016-06-08 14:42:12

thanks guys for the help, i just hope now i can go with 4.6.1.
i am not sure exactly if it really was the 4.6.1 kernel or the 4.6 that caused this problem
but glad to know that i can easily recover

R00KIE · 2016-06-08 14:57:24

So far so good here with i7-6500u + r7 m370, I haven't seen any problems (yet?).

The recommendation to install the LTS kernel is a good one, even if you never use it you will be glad you have it installed if you ever need to use it.

Another thing I recommend is that you create a "rescue usb install" with a DE of your choice and all the utilities you expect to need, basically it is a usb drive with another arch install. Then you wait to update that usb install until you confirm everything is working. You could do it the other way around, update the usb drive first and only then your main system. This applies mostly to kernel or updates that might cause breakage. Again you'll be glad you have a rescue usb drive if you ever need to fix a problem.

Another alternative would be to use btrfs and snapshot your system before the update, if anything goes wrong you can quickly revert all changes, mind you that btrfs might not be as stable as ext4 or other filesystems, although lots of people report they never had problems. In any case a good backup policy is always a good idea.

GhettoGirl · 2016-06-09 12:48:05

So, I finally had some free time to create a backup and update the kernel. Everything is still working with 4.6.1, the kernel finds my root device and is able to mount it. nvidia optimus is also still working.
Thanks again for the great help. Better have a backup you don't need as needing a backup you don't have, am I right

The only problem now is that VMware Workstation is not working anymore, because it is not compatible with the 4.6.1 kernel (yet)
But that's another problem and story.

Regards

EDIT: In case someone is interested: https://communities.vmware.com/thread/5 … 0&tstart=0 a tiny patch to fix the compilation issue on the 4.6.1 and up kernels

Last edited by GhettoGirl (2016-06-09 13:01:26)

ewaller · 2016-06-09 13:53:19

Did you do a full update? (Pacman -Syu)
I do not know about VMware, but VirtualBox uses pacman hooks to rebuild the required kernel modules. VMware may just need to be reinstalled.

GhettoGirl · 2016-06-09 13:56:48

I did a full system upgrade with pacman -Syyu
and VMware rebuilds the kernel modules automatically at startup if they are not installed in the current kernel, but the modules itself are API incompatible with the current kernels and i needed to apply the patches from the link in my previous post

vmware is working very fine with the patched modules, no problems noticed at this time

mis · 2016-06-09 16:16:21

GhettoGirl wrote:

can i "backup" or "dump" a installed pacman package?

You can do that with bacman.

bacman (pacman) v5.0.1

Recreate a package using pacman's database and system files

Usage: bacman [--nocolor] [--pacnew] <installed package name>

Example: bacman linux-headers

Last edited by mis (2016-06-09 16:16:53)

Arch Linux

#1 2016-06-08 12:03:37

[SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#2 2016-06-08 12:20:28

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#3 2016-06-08 12:30:23

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#4 2016-06-08 13:34:04

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#5 2016-06-08 13:46:11

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#6 2016-06-08 14:08:52

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#7 2016-06-08 14:11:58

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#8 2016-06-08 14:12:56

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#9 2016-06-08 14:13:23

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#10 2016-06-08 14:42:12

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#11 2016-06-08 14:57:24

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#12 2016-06-09 12:48:05

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#13 2016-06-09 13:53:19

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#14 2016-06-09 13:56:48

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

#15 2016-06-09 16:16:21

Re: [SOLVED] Kernel 4.6.1 Upgrade? Wasn't that a broken Kernel?

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