mintupdate symlinks old kernels to vmlinuz even if active version is higher

[japaneseTemmie]

Describe the bug
On hybrid systems with both HWE and GA kernels (as backups), mintupdate messes up the vmlinuz and initrd symlinks when updating / installing a GA kernel (older) before the HWE (newer). Requiring manual adjustment with ln -sf.

For example, having a system with both Linux 6.14 HWE and Linux 6.8 GA as backup, when mintupdate shows an update for 6.8 and is applied, the vmlinuz is symlinked to that version, and the active version is now .old. This could cause massive issues with utilities that rely on vmlinuz and initrd.

Screenshots
None

To Reproduce
Steps to reproduce the behavior:

1. Have a hybrid system with both HWE (newer) and GA (older) kernel
2. Update / Install new GA (older) kernel
3. vmlinuz and initrd are now symlinked to the older kernel.

Expected behavior
A clear and concise description of what you expected to happen.

Symlinks should stay as-is if the target kernel update version is lower than the running one.

Distribution:

• [ x ] Linux Mint
• LMDE
• Other (please specify)

Software version:
7.1.1

Logs:
Not needed.

Crash report:
None.

Additional context
None.

Locale:
If the problem is with text not getting displayed correctly, paste the output of the terminal command locale.

[randomnoise]

This could cause massive issues with utilities that rely on vmlinuz and initrd.

initrd.img and vmlinuz symlinks reside in the /boot directory, and files in /boot are used mainly for boot loading, defined by Filesystem Hierarchy Standard.

If you are using GNU GRUB (which is the default bootloader for Linux Mint), symbolic links don't matter; GRUB doesn't care about those symlinks.

So, you don't have to reorder symlinks with ln -sf if you use GRUB.

---

Also, mintupdate is just an intermediary in this situation, and it's more related to Ubuntu's kernel packaging.

The creation and relinking of those symlinks are managed by the linux-update-symlinks command, and this command is initially triggered by the postinst script in the linux-image-*.deb package. ¹

The logic of symlink usage from man linux-update-symlinks:

The symlinks for the primary default kernel version are named vmlinuz or vmlinux (depending on whether the architecture  normally  uses  compressed kernel images) and initrd.img (if it uses an initramfs). The symlinks for the secondary default have the same names with the suffix .old.

[...] it makes a list of kernel versions in decreasing order of priority:

• The given VERSION, if the first argument is install

• The current primary default version, if it exists and is not already listed

[...]The top two entries on the list are the new primary and secondary default versions, and it updates the symlinks accordingly.

The order of installation decides where those symlinks point to, and also it doesn't matter much.

Hope it helps. 👍

Footnotes

1. You can also check it by opening the .deb package with: Right click on the '*.deb' file > Open with Package Installer > Click on 'Included files' button. (the current linux-image-*.deb for example: linux-image-6.8.0-85-generic.deb) ↩