[Bug 828731] [NEW] kdump functionality not working as expected when /boot is a separate partition

[Launchpad Bug Tracker]

You have been subscribed to a public bug by Steve Langasek (vorlon):

SRU Request for Lucid/Maverick/Natty/Oneiric:

[Impact] - When a server is configured with the /boot as a separate
partition, which is the default configuration when LVM installation is
selected, the kdump mechanism fails systematically.

[Development/Stable Fix] - This has been fixed in the development
version with the addition of the following:

  * Backport changes to fix kdump functionality. LP: #828731.
    - debian/kdump.initramfs: call /usr/bin/makedumpfile via a chroot command,
      so that if makedumpfile is statically linked, we get proper library
      resolution.  Thanks to Louis Bouchard <louis.bouchard at canonical.com> for
      the patch.  LP: #785425.
    - debian/kdump.initramfs: handle the possibility that /usr, /boot, or
      /var is on a separate filesystem and needs to be manually mounted before
      calling makedumpfile.  LP: #828731.
    - Depend on makedumpfile, without which the initramfs script doesn't work.
    - Fix an unnecessary bashism.
    - Only install the kdump initramfs script and depend on makedumpfile on
      architectures that makedumpfile supports.


[Test Case] - See 'how to reproduce' below.
[Regression Potential] - Need to ensure kdump works correctly in backported versions.

--

Description : Ubuntu 10.04.2
Release : 10.04

When a server is configured with the /boot as a separate partition,
which is the default configuration when LVM installation is selected,
the kdump mechanism fails systematically.

This is caused by the fact that the ./scripts/init-bottom/0_kdump script
that is loaded into the initrd.img file make the assumption that /boot
is _ALWAYS_ a directory which contains the vmcoreinfo-$KVER file. The
bug is contained within the following code :

   KVER="`uname -r`"
   INFO="$rootmnt/boot/vmcoreinfo-$KVER"
   CRASHFILE="$rootmnt/var/crash/vmcore"
   MAKEDUMPFILE="$rootmnt/usr/bin/makedumpfile"
   LOG="$rootmnt/var/crash/vmcore.log"
   VMCORE="/proc/vmcore"

   # Check that this is a kexec kernel.
   grep -q kdump_needed /proc/cmdline || exit 0

   # Do NOT exit the script after this point, or the system will start
   # booting inside the crash kernel.

   . ./scripts/functions

   # Make sure makedumpfile assumptions are satisfied.
   while ! test -e "$INFO"; do
           panic "kdump: Missing $INFO"
   done
   while ! test -x "$MAKEDUMPFILE"; do
           panic "kdump: Missing $MAKEDUMPFILE"
   done

The test 'while !test -e "$INFO";do' fails if /boot is a separate
partition.

Reproducible: 100%

How to Reproduce :

Pre-requisite : a system or VM installed with LVM and /boot as a
separate partition (default option for LVM installation)

1) install the linux-crashdump package & dependancies
2) Increase the crashkernel= parameter to 128M if the RAM is below 2048M (LP Bug#785394) in /etc/grub.d/10_linux
3) Run sudo update-grub
4) Reboot the system
5) Force a panic with "echo c > /proc/sysrq-trigger

The system will reboot to the kexec kernel with complete network access
enabled :

 # cat /proc/cmdline
 BOOT_IMAGE=/vmlinuz-2.6.32-28-server root=/dev/mapper/Lucid--lvmS-root ro kdump_needed maxcpus=1 irqpoll reset_devices memmap=exactmap memmap=640K at 0K memmap=130412K at 33408K elfcorehdr=163820K

Workaround:
Copy the content of the /boot partition into the /boot directory. This is only valid until the next upgrade of the "linux-image-{version}" package.

How to workaround :

6) Reboot the system
7) Copy the content of the /boot partition into the /boot directory
   # df /boot
   Filesystem           1K-blocks      Used Available Use% Mounted on
   /dev/vda1               233191     17563    203187   8% /boot
   # sudo umount /boot
   # sudo mount /dev/vda1 /mnt
   # sudo cp -pr /mnt/* /boot
   # sudo umount /mnt
   # sudo mount -a
   # sudo echo c > /proc/sysrq-tgrigger

The system will correctly generate a crash dump
   # find /var/crash
    /var/crash
    /var/crash/linux-image-2.6.32-28-server.0.crash

ProblemType: Bug
DistroRelease: Ubuntu 10.04.02
Package: kexec-tools-1-2.0.1-1ubuntu3
Uname: Linux 2.6.32-28-server x86_64
Architecture: amd64

** Affects: kexec-tools (Ubuntu)
     Importance: Medium
     Assignee: Canonical Foundations Team (canonical-foundations)
         Status: Fix Released

** Affects: kexec-tools (Ubuntu Lucid)
     Importance: Medium
     Assignee: Chris J Arges (christopherarges)
         Status: Triaged

** Affects: kexec-tools (Ubuntu Maverick)
     Importance: Medium
     Assignee: Chris J Arges (christopherarges)
         Status: Triaged

** Affects: kexec-tools (Ubuntu Natty)
     Importance: Medium
     Assignee: Chris J Arges (christopherarges)
         Status: Triaged

** Affects: kexec-tools (Ubuntu Oneiric)
     Importance: Medium
     Assignee: Chris J Arges (christopherarges)
         Status: Triaged


** Tags: patch
-- 
kdump functionality not working as expected when /boot is a separate partition
https://bugs.launchpad.net/bugs/828731
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