2.4.21 kernel boot problems

[<tmcd@panix.com>]

I've been trying to upgrade from 2.4.18 to 2.4.21 for several days.  I
used the kernel-source package for the latest 2.4.21 kernel (-3, I
think).  I finally went thru all the screens in "menu xconfig" -- I
was astonished, by the way, at the things that were "n" by default
rather than "m".  I included ("y") the ext2 filesystem, initrd
support, SCSI (I have SCSI as my boot drive), and so forth.  I built
using --initrd; the one time I tried doing without it, at boot time I
got "EBDA is big; kernel setup stack overlaps LILO second stage" and
it hung.

At LILO time, I get

    Warning: '/proc/partitions' does not match '/dev' directory structure.
        Name change: '/dev/ide/host0/bus1/target0/lun0/disc' -> '/dev/hdc'
        The kernel was compiled with DEVFS_FS, but 'devfs=mount' was omitted
            as a kernel command-line boot parameter; hence, the '/dev' directory
            structure does not reflect DEVFS_FS device names.
        Name change: '/dev/ide/host0/bus1/target0/lun0/part1' -> '/dev/hdc1'
        Name change: '/dev/ide/host0/bus1/target1/lun0/disc' -> '/dev/hdd'
        ...

I'm not compiling the new kernel with devfs (it's even grayed out in
xconfig, because I didn't choose to build with experimental code
support).  This is apparently due to the current 2.4.18 kernel, which
was (hey, it was the default), though I don't run devfsd.

However, I don't think it's a LILO problem.  My 2.4.18 kernel is in
there too, with the same stanza structure (just changing the
filename), and that boots as fine as always.

After doing "dpkg -i", running lilo, and booting, I get this as the
last screen (I obviously can't scroll up after the panic):

    Freeing unused kernel memory: 140K freed
    initrd-tools: 0.1.49
            [that's the latest in apt-cache for testing, it appears]
    Warning: can't open /etc/mtab: No such file or directory
    modprobe: modprobe: Can't locate module devfs
    mount: fs type devfs not supported by kernel
    modprobe: modprobe: Can't locate module aic7xxx
    modprobe: modprobe: Can't locate module sg
    modprobe: modprobe: Can't locate module sd_mod
    umount: devfs: not mounted
    modprobe: modprobe: Can't locate module devfs
    mount: fs type devfs not supported by kernel
    modprobe: modprobe: Can't locate module devfs
    modprobe: modprobe: Can't locate module devfs
    mknod: `devfs/root2': Operation not permitted
    mount: special device /devfs/root2 does not exist
    mount: special device /devfs/root2 does not exist
    mount: special device /devfs/root2 does not exist
    mount: special device /devfs/root2 does not exist
    mount: special device /devfs/root2 does not exist
    umount: devfs: not mounted
    umount: devfs: not mounted
    rivot_root: No such file or directory
    /sbin/init: 139: cannot open dev/console: No such file
    kernel panic: Attempted to kill init!

This is particularly confusing because I turned off devfs at xconfig
time and included unconditionally ("y") aic7xxx and sg at least, and
probably sd_mod (I haven't checked).

What sorts of things should I check?  I've gone over the xconfig
settings once already.  Should I post here any other logs or files?

-- 
Tim McDaniel, tmcd@panix.com; tmcd@us.ibm.com is my work address