crashkernel memory reservation ignored

Bug #364414 reported by Jamin W. Collins on 2009-04-21
This bug affects 5 people
Affects Status Importance Assigned to Milestone
linux (Ubuntu)

Bug Description

In attempting to track down a rather elusive kernel panic I've begun trying to use the kdump facility based on information found here ( However, attempting to execute the kexec command results in an error that the crashkernel memory has not been reserved. Near as I can tell, the kernel parameters are correct.

# grep 'Command line:' /var/log/dmesg
[ 0.000000] Command line: root=UUID=66cf90ad-d4ec-4ec1-afb0-3fc3b17e3141 ro vga=0x37d quiet splash crashkernel=384M-2G:64M@16M,2G-:128M@16M

# uname -r

# kexec -p /boot/vmlinuz-2.6.28-11-generic --initrd=/boot/initrd.img-2.6.28-11-generic --append=root=UUID=66cf90ad-d4ec-4ec1-afb0-3fc3b17e3141 irqpoll maxcpus=1
Memory for crashkernel is not reserved
Please reserve memory by passing "crashkernel=X@Y" parameter to the kernel
Then try loading kdump kernel

ProblemType: Bug
Architecture: amd64
DistroRelease: Ubuntu 9.04
MachineType: LENOVO
NonfreeKernelModules: nvidia ath_hal
Package: linux-image-2.6.28-11-generic 2.6.28-11.42
ProcCmdLine: root=UUID=66cf90ad-d4ec-4ec1-afb0-3fc3b17e3141 ro vga=0x37d quiet splash crashkernel=384M-2G:64M@16M,2G-:128M@16M
 PATH=(custom, user)
ProcVersionSignature: Ubuntu 2.6.28-11.42-generic
SourcePackage: linux

Jamin W. Collins (jcollins) wrote :
Irfan Adilovic (irfy) wrote :

I am observing the exact same behavior. Same crashkernel argument, same kernel, same arch, same distro, also nvidia nonfree kernel module.

Same here. Is there any specific data I should report?

Kings (kingslee) wrote :

I get such message "Memory for crashkernel is not reserved" everytime I boot.

kernel argument ro vga=795 crashkernel=384M-2G:64M@16M,2G-:128M@16M, also nvidia nonfree kernel module, using "server" "Linux server1 2.6.28-11-server #42-Ubuntu SMP Fri Apr 17 02:45:36 UTC 2009 x86_64 GNU/Linux" kernel

me too
root=UUID=66252ae1-96e2-4f6b-bfd3-f8194579fa34 ro splash crashkernel=384M-2G:64M@16M,2G-:128M@16M

oh but I don't have any proprietary drivers installed

Duane Waddle (duane-waddle) wrote :

I've seen the same thing on my x86 Jaunty - updating the grub menu.lst to where the argument for crashkernel is just "crashkernel=128M" seems to fix the reservation problem.

Andy Whitcroft (apw) wrote :

On my current setup this is using the following incantion, note that it does not specify the location, can you see if that helps:


Changed in linux (Ubuntu):
assignee: nobody → Andy Whitcroft (apw)
importance: Undecided → Low
status: New → In Progress
status: In Progress → Incomplete
Duane Waddle (duane-waddle) wrote :

Andy's suggestion of "crashkernel=384M-2G:64M,2G-:128M" gets me a proper reservation on 2.6.28-15-generic.

Sep 17 16:21:03 localhost kernel: [ 0.000000] Reserving 128MB of memory at 32MB for crashkernel (System RAM: 3062MB)

Andy Whitcroft (apw) on 2010-06-18
Changed in linux (Ubuntu):
assignee: Andy Whitcroft (apw) → nobody
Jamin W. Collins (jcollins) wrote :

Looks like Lucid gets the reservation correct (crashkernel=384M-2G:64M,2G-:128M) as I see the following:

[ 0.000000] Reserving 128MB of memory at 32MB for crashkernel (System RAM: 9152MB)

Additionally, my system has now been generating crash dumps (and rebooting) instead of simply freezing.

Changed in linux (Ubuntu):
status: Incomplete → Fix Released
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