Package: dkms Version: 2.8.7-2 Severity: important Dear Maintainer,
When upgrading the kernel (with unattended upgrades) on a system with a dkms-built module, dkms fails to build the new module. This is the excerpt from "/var/log/apt/term.log": Selecting previously unselected package linux-image-5.10.0-0.bpo.9-amd64. [...] Preparing to unpack .../linux-image-5.10.0-0.bpo.9-amd64_5.10.70-1~bpo10+1_amd64.deb ...(Reading database ... 149449 files and directories currently installed.) Unpacking linux-image-5.10.0-0.bpo.9-amd64 (5.10.70-1~bpo10+1) ...~bpo10+1_amd64.deb ... Preparing to unpack .../linux-image-amd64_5.10.70-1~bpo10+1_amd64.deb ... Unpacking linux-image-amd64 (5.10.70-1~bpo10+1) over (5.10.46-4~bpo10+1) ... Setting up linux-image-5.10.0-0.bpo.9-amd64 (5.10.70-1~bpo10+1) ...10+1) ... I: /vmlinuz.old is now a symlink to boot/vmlinuz-5.10.0-0.bpo.8-amd64 I: /initrd.img.old is now a symlink to boot/initrd.img-5.10.0-0.bpo.8-amd64 I: /vmlinuz is now a symlink to boot/vmlinuz-5.10.0-0.bpo.9-amd64po.8-amd64 I: /initrd.img is now a symlink to boot/initrd.img-5.10.0-0.bpo.9-amd64 /etc/kernel/postinst.d/dkms:ink to boot/initrd.img-5.10.0-0.bpo.9-amd64 Error! Your kernel headers for kernel 5.10.0-0.bpo.9-amd64 cannot be found. Please install the linux-headers-5.10.0-0.bpo.9-amd64 package,not be found. or use the --kernelsourcedir option to tell DKMS where it's located /etc/kernel/postinst.d/initramfs-tools:tell DKMS where it's located update-initramfs: Generating /boot/initrd.img-5.10.0-0.bpo.9-amd64 /etc/kernel/postinst.d/zz-update-grub:trd.img-5.10.0-0.bpo.9-amd64 Generating grub configuration file ... Found linux image: /boot/vmlinuz-5.10.0-0.bpo.9-amd64 Found initrd image: /boot/initrd.img-5.10.0-0.bpo.9-amd64 Found linux image: /boot/vmlinuz-5.10.0-0.bpo.8-amd64md64 Found initrd image: /boot/initrd.img-5.10.0-0.bpo.8-amd64 Found linux image: /boot/vmlinuz-5.10.0-0.bpo.7-amd64md64 Found initrd image: /boot/initrd.img-5.10.0-0.bpo.7-amd64 Found linux image: /boot/vmlinuz-5.10.0-0.bpo.5-amd64md64 Found initrd image: /boot/initrd.img-5.10.0-0.bpo.5-amd64 Adding boot menu entry for EFI firmware configurationmd64 doneng boot menu entry for EFI firmware configuration Setting up linux-image-amd64 (5.10.70-1~bpo10+1) ... Log ended: 2021-11-01 06:26:47.10.70-1~bpo10+1) ... Log ended: 2021-11-01 06:26:47 Log started: 2021-11-01 06:26:50 Selecting previously unselected package linux-headers-5.10.0-0.bpo.9-common. [...] Preparing to unpack .../linux-headers-5.10.0-0.bpo.9-common_5.10.70-1~bpo10+1_all.deb ... Unpacking linux-headers-5.10.0-0.bpo.9-common (5.10.70-1~bpo10+1) ... Selecting previously unselected package linux-headers-5.10.0-0.bpo.9-amd64. Preparing to unpack .../linux-headers-5.10.0-0.bpo.9-amd64_5.10.70-1~bpo10+1_amd64.deb ... Unpacking linux-headers-5.10.0-0.bpo.9-amd64 (5.10.70-1~bpo10+1) ... Preparing to unpack .../linux-headers-amd64_5.10.70-1~bpo10+1_amd64.deb ... Unpacking linux-headers-amd64 (5.10.70-1~bpo10+1) over (5.10.46-4~bpo10+1) ... Setting up linux-headers-5.10.0-0.bpo.9-common (5.10.70-1~bpo10+1) ...0+1) ... Setting up linux-headers-5.10.0-0.bpo.9-amd64 (5.10.70-1~bpo10+1) .... Setting up linux-headers-amd64 (5.10.70-1~bpo10+1) ...-1~bpo10+1) ... Log ended: 2021-11-01 06:27:32(5.10.70-1~bpo10+1) ... Log ended: 2021-11-01 06:27:32 This appareantly happens because unatteneded upgrade unnecessarily splits the upgrades of the kernel image and linux-headers into two separate apt calls, as there is no dependency between them (in either way). With a bit of bad luck the installation of the headers happens afterwards and the trigger from dkms fails to rebuild the module. I observed this with several versions of dkms. I've set the severity to "important", because the failed dkms upgrade does not seem to fail the upgrade which together with unattended upgrades sneakily "removes" a module from the most recent kernel which will lead to the next boot failing if correct booting requires that module.
