Skip to content

Revert "Avoid updating the initramfs twice for some cases"

Benjamin Drung requested to merge bdrung/initramfs-tools:revert-avoid-double-generation into debian/latest

This reverts commit 7f2ed354.

When installing a kernel package and a package with a trigger for update-initramfs in one go, the update of the initramfs is skipped in some cases.

In a clean chroot, populated with debootstrap for "trixie", run

apt install linux-image-amd64 plymouth-theme-mobian

Result:

[...]
Setting up linux-image-6.12.32-amd64 (6.12.32-1) ...
I: /vmlinuz.old is now a symlink to boot/vmlinuz-6.12.32-amd64
I: /initrd.img.old is now a symlink to boot/initrd.img-6.12.32-amd64
I: /vmlinuz is now a symlink to boot/vmlinuz-6.12.32-amd64
I: /initrd.img is now a symlink to boot/initrd.img-6.12.32-amd64
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-6.12.32-amd64
Setting up linux-image-amd64 (6.12.32-1) ...
Setting up plymouth-theme-mobian (1.1) ...
update-alternatives: using /usr/share/plymouth/themes/mobian/mobian.plymouth to provide /usr/share/plymouth/themes/default.plymouth (default.plymouth) in auto mode
Processing triggers for libc-bin (2.41-8) ...
Processing triggers for initramfs-tools (0.148.2) ...
update-initramfs: /boot/initrd.img-6.12.32-amd64 has already been updated since Mon Jun 23 06:07:09 2025.

The initramfs is updated after setup of the kernel package. It is NOT updated again after setup of package plymouth-theme-mobian, which is wrong. The files that are installed by package plymouth-theme-mobian are missing in the initramfs (and the plymouth splash screen will not work).

This is what happens here:

  1. Another package is installed that calls "update-initramfs -u". This activates the trigger, and we store a timestamp for it.
  2. linux-image-6.12.32-amd64 is installed. This calls the initramfs-tools hook which synchronously builds the initramfs.
  3. plymouth-theme-mobian is installed. This activates the trigger through a triggers control file.
  4. The trigger runs and passes the timestamp from (1) through to update-initramfs. update-initramfs sees the current image is newer than that, and skips the update.

We correctly handle the case where the trigger is only activated through update-initramfs -u, or only through a triggers control file or direct invocation of dpkg-trigger. But when both methods are used, this bug is possible because a timestmap file is present and it is wrong.

So revert the optimised trigger handling until dpkg itself records timestamps for trigger activation (see bug #1099136).

Closes: #1108204

Merge request reports