Why does `apt install linux-headers-generic` install old headers for the newest stable kernel?

Question

I can boot a vanilla pi-4 with kernel8.img (Feb 15, 2023) to release 5.15.84-v8+ ... the pi-4 runs admirably.

# ls -ltr /boot/*.img
-rwxr-xr-x 1 root root 8194604 Feb 15 18:02 /boot/kernel8.img

# uname -r
5.15.84-v8+

But when I install linux-headers-generic, I get the message that version 5.10.162-1 already installed...

# apt install linux-headers-generic
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Note, selecting 'linux-headers-arm64' instead of 'linux-headers-generic'
linux-headers-arm64 is already the newest version (5.10.162-1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

eg.

$ apt list --installed "linux-headers-5.1*.*-"{common,arm64}
Listing... Done
linux-headers-5.10.0-21-arm64/stable-security,now 5.10.162-1 arm64 [installed,automatic]
linux-headers-5.10.0-21-common/stable-security,stable-security,now 5.10.162-1 all [installed,automatic]

Even more terrible: linux-headers-5.15.84-v8+-arm64 is missing from the repo.

How/where can I force apt to download the newest stable linux-headers-5.15.84-v8+-arm64 headers? (as per the actual boot kernel)

Note: I'm trying to build fresh dkms drivers for zfs, and zfs's build needs the most current headers.

Answer 1

I had the same issue, you can fix it by using

 sudo apt install raspberrypi-kernel-headers

instead of the generic headers.
That fixed the issue for me and v4l2loopback at least.

I found the answer at the bottom of this page.

Answer 2

test case: build current stable zfs divers for pi4.

Record current kernel release:

$ ls -lt /boot/kernel8.img
-rwxr-xr-x 1 root root 8194604 Feb 16 09:40 /boot/kernel8.img
$ uname -r
5.15.84-v8+

Upgrade to the most current packages:

$ sudo apt update
$ sudo apt upgrade

Prep linux for a build:

$ sudo apt install -y build-essential autoconf automake libtool gawk alien fakeroot dkms libblkid-dev uuid-dev libudev-dev libssl-dev zlib1g-dev libaio-dev libattr1-dev libelf-dev python3 python3-dev python3-setuptools python3-cffi libffi-dev python3-packaging git libcurl4-openssl-dev

At this point you already have headers for 5.10.0-21, but sadly these are of not much use for building modules for the 5.15.84-v8+ kernel! :-( ... eg. ...

# apt list --installed "linux-headers*"
Listing... Done
linux-headers-5.10.0-21-arm64/stable-security,now 5.10.162-1 arm64 [installed,automatic]
linux-headers-5.10.0-21-common/stable-security,stable-security,now 5.10.162-1 all [installed,automatic]
linux-headers-arm64/stable-security,now 5.10.162-1 arm64 [installed]

Instead, you must apt install the additional raspberrypi-kernel-headers package required to build on "Raspberry Pi OS" (aka debian11 on pi4/arm/64)

$ sudo apt install raspberrypi-kernel-headers

Download and build the package containing the driver:

$ git clone https://github.com/openzfs/zfs
$ cd zfs
$ git checkout master
$ sh autogen.sh
$ ./configure
$ make -s -j$(nproc)
$ make -s -j$(nproc) deb

Install the required packages and test:

$ sudo apt install -y $PWD/{zfs,zfs-dkms,libzfs5,libnvpair3,libuutil3}_2.1.99-1734_arm64.deb $PWD/kmod-zfs-`uname -r`_2.1.99-1734_arm64.deb
$ sudo zpool import -a

Enable zfs on boot:

$ sudo systemctl enable --now zfs-import-scan.service zfs-mount zfs-import.target zfs-zed zfs.target zfs-import-cache.service

Reboot and check zfs now works OK! (And finds all existing filesystems... if you have any)

$ df -PhT -t zfs
Filesystem           Type      Size  Used Avail Use% Mounted on
zfs_test             zfs       136G  107G   29G  80% /zfs_test
zfs_vault            zfs       2.9T  2.7T  192G  94% /zfs_vault

Warning: Do not run rpi-update, as this appears will install beta/unstable kernel-6.0.xx (and fresh firmware) and you will stuck in beta tester land... ;-)

But if you do... DougieLawson: "If you update the kernel with rpi-update you'd need to run rpi-source to get the matching kernel source tree and headers."

eg. If you run rpi-update you will get something like:

# modprobe zfs
modprobe: FATAL: Module zfs not found in directory /lib/modules/6.xx.xx-v8+

Note the 6.0.xx in /lib/modules/6.0.xx in the above.

See also:

• Building ZFS - by OpenZFS
• Do I install the current "correct" kernel headers? (and how)
• manjaro: ZFS pool does not load during boot - "ConditionPathIsDirectory=/sys/module/zfs was not met".