Custom kernel - lilo complains device-mapper missing
 

Debian Unstable.

I made a custom 2.6.5 kernel with raid/lvm stuff removed, and now lilo complains as follows:

/dev/mapper/control: open failed: No such device
Is device-mapper driver missing from kernel?
/dev/mapper/control: open failed: No such device
Is device-mapper driver missing from kernel?
Incompatible libdevmapper 1.00.15-ioctl (2004-04-07)(compat) and kernel driver

Is this important? It continues without a FATAL message.

If I don't need raid/lvm support why would I need this compiled in?

Is the answer to apt-get remove libdevmapper?

[ bump ]

Any ideas? I've made several custom kernels and this seems to happen with many of them. I wish everything just worked properly without complaining about things that probably aren't compulsory.

I don't use devfs, BTW.

I could post my .config if someone wants to help.

Should I forget about the extra bloat and leave it in?

Hi

I know this is an old thread but I had the same problem and when I found it I wished that someone had answered the question :-)

I think if the currently running kernel image does not have
Multi devices support (RAID) -> select device mapper support
turned on (can be a module) then this warning will be issued. Also, the module this option builds has to be loaded (if you build it as a module). You can check if it is loaded by running:

cat /proc/modules | grep dm_mod

If it is not in the list, but you have compiled it as a module for the running kernel, you should run

modprobe dm_mod

For me after doing so, the warning has disappeared.

Jozsi


PS: I am using Slackware 12, kernel 2.6.20.19. I am not sure if this works on other systems.

July 2010, 2.6.33.4 kernel and same problem.

In my attempts to resolve this I have found.

Device-mapper is now optional, and is found under the MD config items in menuconfig. It apparently is only needed to map logical volumne addresses to drive/sectors because of RAID and LVM, and for simple drives was not considered necessary.

The current Lilo is not coping well with device-mapper being optional.
In my opinion this is a Lilo bug.
Lilo has had the ability to cope with simple drives and seems to still have that ability, at least my boots have not failed, yet.
Just to be sure, I change back to 2.4 and reinstall lilo again, because
I do not get any error messages that way.