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Sometimes when I try to upgrade my packages a small number of packages are not upgraded.

root@pc:/home/user# sudo apt-get upgrade
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
  linux-headers-amd64 linux-image-amd64
0 upgraded, 0 newly installed, 0 to remove and 2 not upgraded.

What is the rationale behind the system deciding not to upgrade those packages? How can I upgrade them anyway?

mari2432
  • 11

1 Answers1

3

The two most common reasons are:

  1. One or more packages that the "kept back" packages Depend upon are not yet available in the archive. This is most common if you use Debian Sid or Debian Testing, or some other "rolling" type distribution, but sometimes also occurs with regular and security update distros.

    It's a matter of timing - when packages get uploaded, accepted into the archive, and then distributed to your local repo mirror. It usually settles with a day or two, but can sometimes take longer if there is a major upgrade of something in progress (e.g. a new version of KDE or Gnome or something that involves lots of packages) and/or one package is holding up lots of other packages.

    It's not worth worrying about. Just wait and try to apt update and apt upgrade or apt dist-upgrade again in a few days.

  2. You have manually held some of the packages (e.g. with apt-mark hold). You can fix this yourself with apt-mark unhold.

    BTW, I recommend holding both linux-headers-amd64 and linux-image-amd64 anyway, especially if you are using DKMS packages such as nvidia-kernel-dkms or zfs-dkms which may conflict with or require new patches to work with new kernels (you should not upgrade your kernel until you know that these DKMS packages will compile with the new kernel! and your *dkms* packages should be held too and only upgraded manually). Then you can upgrade them manually (and hold them again) with something like:

     apt-get install linux-image-amd64 linux-headers-amd64 ; apt-mark hold linux-image-amd64 linux-headers-amd64

You can begin investigating the actual cause on your system with apt-cache (particularly the show and policy sub-commands) and aptitude (which has useful why and why-not sub-commands). For example, try running:

apt-cache show linux-image-amd64
apt-cache policy linux-image-amd64

aptitude why-not linux-image-amd64
aptitude why linux-image-amd64

You'll need to read and understand the apt and dpkg documentation to interpret the output. Most of it is fairly straight-forward and obvious in meaning, but some is not - particularly the aptitude why output, which requires understanding of the code letters at the beginning of each output line.

cas
  • 78,579
  • Given that the kernel ABI was just bumped in stable, I suspect that the reason here is a third one: apt-get upgrade doesn’t install new packages and will hold back any upgrades that need new packages. See the linked dupe although I suspect you know all this already ;-). – Stephen Kitt Nov 08 '22 at 05:34
  • yeah, i didn't even notice that it was an 'apt-get upgrade' rather than `dist-upgrade', otherwise I would have mentioned the third common reason. I almost never run upgrade, only when I don't want anything to be auto-removed by a dist-upgrade. – cas Nov 08 '22 at 08:53