Ubuntu
flash-kernel package

On armel (Babbage platform), kernel image upgrading breaks if Ubiquity is instructed not to install a bootloader

Bug #365053 reported by Dave Martin
14
This bug affects 1 person
Affects Status Importance Assigned to Milestone
flash-kernel (Ubuntu)
Fix Released
High
Ubuntu ARM Team
initramfs-tools (Ubuntu)
Fix Released
Medium
Ubuntu ARM Team

Bug Description

Binary package hint: ubiquity

If the "install bootloader" option is cleared (in the advanced options on the last page of the Ubiquity installer dialogs), it appears that no /etc/flash-kernel.conf configuration file is generated for flash-kernel to use.

However, the linux image postinst script unconditionally runs flash-kernel to reprogram the kernel and (I think) initrd on the SD card. flash-kernel gets confused if there is no /etc/flash-kernel.conf; some shell variables remain unset in flash-kernel causing odd errors.

This means that if the kernel image package (e.g., linux-image-2.6.28-11-imx51) is upgraded, the postinst script will fail, leaving that package half-configured. This also seems to prevent apt-get (probably also higher-level package managers) from working until the problem is resolved manually.

This will not affect typical users who just install with the default configuration; however I already had a different SD card set up with a suitable kernel for booting purposes, and wanted to avoid clobbering the SD card with the live image on it so that I could use it again, reproducibly.

Here's what happens when I try to upgrade the kernel image just after a clean install:
(Actually, there's no newer package available, so I simulate this by reinstalling the kernel image)

root@ubuntu-desktop:~# apt-get --reinstall install linux-image-2.6.28-11-imx51
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
Need to get 0B/8235kB of archives.
After this operation, 0B of additional disk space will be used.
Do you want to continue [Y/n]?
(Reading database ... 95002 files and directories currently installed.)
Preparing to replace linux-image-2.6.28-11-imx51 2.6.28-11.42 (using .../linux-image-2.6.28-11-imx51_2.6.28-11.42_armel.deb) ...
Done.
Unpacking replacement linux-image-2.6.28-11-imx51 ...
Setting up linux-image-2.6.28-11-imx51 (2.6.28-11.42) ...
Running depmod.
update-initramfs: Generating /boot/initrd.img-2.6.28-11-imx51
 is not a block device
Failed to create initrd image.
dpkg: error processing linux-image-2.6.28-11-imx51 (--configure):
 subprocess post-installation script returned error exit status 2
Errors were encountered while processing:
 linux-image-2.6.28-11-imx51
E: Sub-process /usr/bin/dpkg returned an error code (1)

Poking around, I can see that there is no flash-kernel.conf (it _is_ there with sane contents of bootloader installation was enabled)

root@ubuntu-desktop:~# ls --color=never /etc/flash-kernel.conf
ls: cannot access /etc/flash-kernel.conf: No such file or directory

Since flash-kernel.conf is just sourced as a shell script, I can artificially make flash-kernel "succeed" by this ugly hack (but it's obviously not the right solution!)

root@ubuntu-desktop:~# echo exit 0 >/etc/flash-kernel.conf
root@ubuntu-desktop:~# dpkg --pending --configure
Setting up linux-image-2.6.28-11-imx51 (2.6.28-11.42) ...
Running depmod.
update-initramfs: Generating /boot/initrd.img-2.6.28-11-imx51
Not updating initrd symbolic links since we are being updated/reinstalled
(2.6.28-11.42 was configured last, according to dpkg)
Not updating image symbolic links since we are being updated/reinstalled
(2.6.28-11.42 was configured last, according to dpkg)

root@ubuntu-desktop:~# exit

ProblemType: Bug
Architecture: armel
DistroRelease: Ubuntu 9.04
Package: ubiquity 1.12.12
ProcEnviron:
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
Uname: Linux 2.6.28-11-imx51 armv7l

Revision history for this message
Dave Martin (dave-martin-arm) wrote :
Revision history for this message
Loïc Minier (lool) wrote :

Could you please attach your /etc/kernel-img.conf?

tags: added: arm
Revision history for this message
Dave Martin (dave-martin-arm) wrote :
Revision history for this message
Dave Martin (dave-martin-arm) wrote :

Perhaps do_initrd should be "no" when not installing the bootloader?

Revision history for this message
Loïc Minier (lool) wrote :

So I think the installer does thing correctly in that it doesn't pull a bootloader and doesn't setup kernel-img.conf to run it (on systems where the bootloader is installed, kernel-img.conf has: "postinst_hook = flash-kernel"). The only problem is that flash-kernel gets installed while it shouldn't. I suspect this is due to the Recommends of linux-image-imx51, but I need to confirm where it gets pulled.

Revision history for this message
Dave Martin (dave-martin-arm) wrote :

I see; yes, that sounds plausible.

So it might make sense to remove the Recommends from linux-image-imx51 and install flash-kernel explicitly if the bootloader installation option is enabled in ubiquity?

Revision history for this message
Oliver Grawert (ogra) wrote :

i dont think the dependency is wrong, the code in update-initramfs should simply respect that there is no postinst_hook set (like the postinst of the kernel package itself seems to do here) in the linux-image postinst perl script the following code appears:

## Run user hook script here, if any
if ($postinst_hook) {
  &run_hook("postinst", $postinst_hook);
}

Revision history for this message
Loïc Minier (lool) wrote :

So flash-kernel is installed in the live-system (I see it in the manifest); perhaps it shouldn't be, or should be removed from the installed, I'm not sure.

There's a way I can prevent it to fail though which is to mark it as unsupported when there's no flash-kernel.conf; I think I'll upload that to karmic.

affects: ubiquity (Ubuntu) → flash-kernel (Ubuntu)
Revision history for this message
Loïc Minier (lool) wrote :

Subscribed Ubuntu Installer folks to hear what they think of the overall approach :-)

Revision history for this message
Emmet Hikory (persia) wrote :

There are two aspects to this bug: firstly, that flash-kernel really shouldn't fail in the absence of a configuration. The second is that update-initramfs should be checking the appropriate hook from kernel-img.conf. The hook to call flash-kernel will only be present if either manually added, or added by flash-kernel-installer (in the case where the user chose to install the bootloader).

Revision history for this message
Oliver Grawert (ogra) wrote :

the fix for update-initramfs

--- ../update-initramfs 2009-04-23 12:15:22.000000000 +0200
+++ update-initramfs 2009-04-23 12:23:05.000000000 +0200
@@ -263,7 +263,9 @@
   zipl
  fi
  if flash-kernel --supported >/dev/null 2>&1; then
- flash-kernel
+ if grep -q flash-kernel /etc/kernel-img.conf; then
+ flash-kernel
+ fi
  fi
 }

Revision history for this message
Loïc Minier (lool) wrote :

I don't like the crude greq; here's a nicer version of this option

Revision history for this message
Loïc Minier (lool) wrote :

And this is another option which drops --supported.

Revision history for this message
Loïc Minier (lool) wrote :

My preference for initramfs-tools is still to add a new post-update-initramfs option which would allow dropping the bunch of bootloader calls in update-initramfs (elilo and folks).

Revision history for this message
Loïc Minier (lool) wrote :
Paul Larson (pwlars)
tags: removed: arm
Paul Larson (pwlars)
Changed in flash-kernel (Ubuntu):
status: New → Triaged
Changed in initramfs-tools (Ubuntu):
status: New → Triaged
Changed in flash-kernel (Ubuntu):
importance: Undecided → Medium
Changed in initramfs-tools (Ubuntu):
importance: Undecided → Medium
Revision history for this message
Tobin Davis (gruemaster) wrote :

I would think that flash-kernel-installer.postinst script should have the ability to ensure that flash-kernel is enabled in /etc/kernel-img.conf after installing the flash-kernel package. This is now affecting the omap preinstalled images, as they don't use ubiquity to create the image (except for oem-tools on first boot). Upgrading to high, as currently updating the kernel in Maverick on omap fails to run flash-kernel.

Changed in flash-kernel (Ubuntu):
importance: Medium → High
milestone: none → ubuntu-10.10-beta
Revision history for this message
Tobin Davis (gruemaster) wrote :

This issue should be revisited with natty.

Changed in flash-kernel (Ubuntu):
assignee: nobody → Ubuntu armel porters (ubuntu-armel)
milestone: ubuntu-10.10-beta → none
Changed in initramfs-tools (Ubuntu):
assignee: nobody → Ubuntu armel porters (ubuntu-armel)
Revision history for this message
Tobin Davis (gruemaster) wrote :

This issue seems to have been resolved. Marking as "Fix Released".

Changed in flash-kernel (Ubuntu):
status: Triaged → Fix Released
Changed in initramfs-tools (Ubuntu):
status: Triaged → Fix Released
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