Re: kexec -l ... --ramdisk=<blah>

[ebiederm@xmission.com (Eric W. Biederman)]

bruce@it.usyd.edu.au (Bruce Janson) writes:

> i Eric, Randy,
>     Thanks for kexec.  It seems to mostly work well, and is an
> improvement on the other contenders (2-kernel monte, bootimg and lobos).

Thanks.  I am bouncing this to lkml since this at the moment does not
appear to be a kexec issue.

I just checked and initial ramdisks work.

The kernel messages I see look like:
> checking if image is initramfs...it isn't (no cpio magic); looks like an initrd
> Freeing initrd memory: 1503k freed


>     I am trying to use kexec's "--ramdisk=..." facility.  Both
> loader and loadee kernels are Linux 2.6.7.  The new kernel loads and
> runs successfully until it tries to mount its root file system.
> Then it fails with this:
> 
>   RAMDISK: Couldn't find valid RAM disk image starting at 0.

That message is because of your root=/dev/ram command line,
and really has nothing to do with your initial ramdisk.
 
>     I believe that the ramdisk image that I supply (to kexec)
> is a well-formed ext2 file system image.  Just for grins I also tried
> a copy of a RedHat 9.0 /boot/initrd* from one of our servers but it
> produced the same failure and message.

Perhaps you did not compile in initrd support?
 
>     The failure message (from .../linux/init/do_mounts_rd.c:130)
> suggests that the booted kernel has not found a valid ext2 superblock
> at the expected ramdisk location.  As I trust the format of the
> ramdisk image I now suspect that the ramdisk location may be wrong.

Unless you have gotten quite creative I doubt it.  Looking at
all of the kernel messages would have been more interesting.

> Any suggestions that you can offer would be appreciated.

See above.

Eric