dracut-core: Shipping /usr/lib/kernel/install.d/50-dracut.install causes two initrds to be installed on kernel postinst

[Alexander Kurtz]

Control: affects -1 systemd-boot

Hi,

I just upgraded to Trixie and ran into this bug. Unfortunately it seems
to have more unintended consequences. Here's (one of) the problem(s):

   1. dracut ships /etc/kernel/postinst.d/dracut which generates an
      initramfs into /boot/initrd.img-$VERSION and correctly
      handles the hostonly={yes|no} setting from the configuration.
      
   2. dracut also ships /usr/lib/kernel/install.d/50-dracut.install
      which generates an initramfs into
      $KERNEL_INSTALL_STAGING_AREA/initrd *but hardcodes*
      "--add-confdir hostonly" as a command line argument. The latter
      has been fixed by PR [0] (commits [1-2]) but AFAICT there has
      been no release yet which contains these changes.
      
   3. systemd-boot ships /etc/kernel/postinst.d/zz-systemd-boot which
      calls kernel-install, which calls
      /usr/lib/kernel/install.d/50-dracut.install and then
      /usr/lib/kernel/install.d/90-loaderentry.install which does this:
      
      for initrd in "${KERNEL_INSTALL_STAGING_AREA}"/microcode* "${@}"
      "${KERNEL_INSTALL_STAGING_AREA}"/initrd*; do [ -f "$initrd" ] ||
      continue echo "initrd $ENTRY_DIR/${initrd##*/}" have_initrd=yes
      done
      
      This effectively means that *both* initramfs files end up in the
      loader entry for systemd-boot and thus *both* initramfs entries
      are loaded by the kernel on boot
      
   4. This effectively concatenates/merges to *full* initramfs images
      (instead of only partial overlays as intended), one of which is a
      hostonly=yes initramfs even though the user may have explicitly
      configured hostonly=no. On my system this leads to some warnings
      about missing devices on boot, but fortunately the system still
      boots. However, other users may not be so lucky.
      
The problem can be worked around by disabling the .install file:

ln -s /dev/null /etc/kernel/install.d/50-dracut.install
dpkg-reconfigure linux-image-`uname -r`

However, I think the correct solution is for dracut to *stop shipping*
the /usr/lib/kernel/install.d/50-dracut.install file completely, at
least until a consensus has been found as to which part of the software
stack (kernel postinst vs. systemd-boot->kernel-install) *should*
generate the initramfs in Debian. This is most likely a policy decision
[3] involving the systemd and Linux maintainers.

Best regards

Alexander Kurtz

[0] https://github.com/dracut-ng/dracut-ng/pull/1238
[1] https://github.com/dracut-ng/dracut-ng/commit/663e720e76407cf10e4e5c8d834b292beba828fa
[2] https://github.com/dracut-ng/dracut-ng/commit/62fdf59c94ef7ec2261d054384ceddff39c3643b
[3] https://kernel-team.pages.debian.net/kernel-handbook/ch-update-hooks.html