[Bug 1981385] Re: initrd lacks modules to mount boot image from http boot

[Launchpad Bug Tracker]

This bug was fixed in the package initramfs-tools - 0.142ubuntu23

---------------
initramfs-tools (0.142ubuntu23) noble; urgency=medium

  [ Daniel van Vugt ]
  * hooks/framebuffer: Only add simple/tiny framebuffer drivers. This is to
    limit the size of initrd when FRAMEBUFFER=y is soon enabled for desktop
    installations (LP: #1970069, #1869655).

  [ Benjamin Drung ]
  * autopkgtest: Increase QEMU timeouts on arm64/armhf
  * hooks/framebuffer:
    - Move adding framebuffer drivers into auto_add_modules
    - Drop looking in $MODULESDIR/initrd/ for kernel modules
    - Support MODULES=dep in framebuffer hook

initramfs-tools (0.142ubuntu22) noble; urgency=medium

  * autopkgtest: update systemd-udevd path from /lib to /usr/lib

initramfs-tools (0.142ubuntu21) noble; urgency=medium

  [ Benjamin Drung ]
  * configure_networking:
    - Increase minimum timeout to 30 seconds
    - Fix configuring BOOTIF when using iSCSI (LP: #2056187)
    - Set interface MTU if provided by the DHCP server (LP: #2056194)
    - log sleep durations before retries
  * Copy /etc/passwd into the initramfs to allow dhcpcd running as dhcpcd user
  * Replace obsolete pkg-config build-dependency by pkgconf

  [ Dan Bungert ]
  * Restore nvdimm and dax pmem-related modules (LP: #1981385)

 -- Benjamin Drung <bdrung at ubuntu.com>  Thu, 21 Mar 2024 10:57:54 +0100

** Changed in: initramfs-tools (Ubuntu)
       Status: Fix Committed => Fix Released

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https://bugs.launchpad.net/bugs/1981385

Title:
  initrd lacks modules to mount boot image from http boot

Status in initramfs-tools package in Ubuntu:
  Fix Released
Status in initramfs-tools source package in Jammy:
  Fix Released

Bug description:
  [ Impact ]

   * If you use UEFI http boot to boot an image (rather than an EFI
     executable) and get all the way to a normal userspace, you can
     access the boot image as /dev/pmem0. But this is not accessible in
     the initrd; presumably some modules are missing.
   * This is desirable because then you can just feed an installer ISO to
     a machine via http boot and the installer just works as normal
   * Add support for physical pmem devices, and simulation thereof with
     the memmap kernel command line parameter
   * The initrd is larger

  [ Test Plan ]

   * unpack an initrd on a Jammy system with the generic kernel
     metapackage with unmkinitramfs
   * observe that the directories kernel/drivers/{nvdimm,dax,acpi/nfit}
     are not present
   * install the updated initramfs-tools packages from proposed
   * again unpack an initrd on a Jammy system with the generic kernel
     metapackage with unmkinitramfs
   * observe that the directories kernel/drivers/{nvdimm,dax,acpi/nfit}
     are present now
   * reboot to confirm that the system still boots
   * modify /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT to contain a
     memmap entry - memmap=1G!4G seems to work on many systems over 4G of
     RAM, or do `dmesg | grep BIOS-e820` to observe the memory regions
     and select a usable one. 
   * update-grub and reboot again
   * a /dev/pmem device should now be present on the system

  [ Where problems could occur ]

   * The growth of the files in /boot will accelerate issues for users
     who have a dedicated boot partition that is not large enough

  [ Other Info ]

   * Details on the memmap kernel command line parameter:
     https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt
   * PMEM simulation with memmap:
     https://docs.pmem.io/persistent-memory/getting-started-guide/creating-development-environments/linux-environments/linux-memmap

  
  [ Original Bug Description ]

  If you use UEFI http boot to boot an image (rather than an EFI
  executable) and get all the way to a normal userspace, you can access
  the boot image as /dev/pmem0. But this is not accessible in the
  initrd; presumably some modules are missing. Dimitri added some
  modules that are clearly going to be necessary (kernel/drivers/nvdimm)
  in 0.140ubuntu14 and I added kernel/drivers/dax too in local
  experiments but this appears not to be enough to get it to appear.

  This is desirable because then you can just feed an installer ISO to a
  machine via http boot and the installer just works as normal (the
  speed and, uh, quality, of the implementation of HTTP in a given
  machine's firmware may mean this isn't always the best option but it
  would be nice if it worked in case someone's machine actually does
  this well).

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