Software raid broken in recent kernels

[Dennis Jacobfeuerborn]

Dave Jones wrote:
> On Tue, Mar 11, 2008 at 07:32:20PM +0100, Dennis Jacobfeuerborn wrote:
>   >  I can't get recent kernels to boot because they don't seem to find
>   >  necessary devices ("no devices found for /dev/mdX"). The status is as follows:
>   >
>   >  works ->  kernel-2.6.25-0.87.rc3.git4.fc9
>   >  fails ->  kernel-2.6.25-0.101.rc4.git3.fc9
>   >  fails ->  kernel-2.6.25-0.105.rc5.fc9
>   >
>   >  I checked bugzilla but couldn't find any relevant kernel bugs. Should I
>   >  file one or is this already known?
>
> I don't recall anything in md changing recently that could explain this.
> I'm more inclined to believe it's another mkinitrd bug.
> Could you pull apart the working/broken initrds and compare them to see
> if there's something obviously different?

The only obvious difference is that the newer kernels no longer load sd_mod 
and the references to sd_mod from modules.alias have been removed.

BTW these are simple unencrypted raid-1 devices:

[root at nexus t]# uname -a
Linux nexus 2.6.25-0.78.rc3.git1.fc9 #1 SMP Fri Feb 29 02:19:15 EST 2008 
i686 athlon i386 GNU/Linux
[root at nexus t]# rpm -q mkinitrd
mkinitrd-6.0.34-1.fc9.i386
[root at nexus t]# cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4]
md0 : active raid1 sda2[0] sdb2[1]
       104320 blocks [2/2] [UU]

md1 : active raid1 sda3[0] sdb3[1]
       1052160 blocks [2/2] [UU]

md2 : active raid1 sda5[0] sdb5[1]
       307628544 blocks [2/2] [UU]

unused devices: <none>

Relevant entries from fstab:
/dev/md2            /                       ext3    defaults,noatime 1 1
/dev/md0            /boot                   ext3    defaults,noatime 1 2
/dev/md1            swap                    swap    defaults        0 0

Relevant entries from grub.conf:
title Fedora (2.6.25-0.105.rc5.fc9)
	root (hd0,1)
	kernel /vmlinuz-2.6.25-0.105.rc5.fc9 ro root=/dev/md2
	initrd /initrd-2.6.25-0.105.rc5.fc9.img
title Fedora (2.6.25-0.78.rc3.git1.fc9)
	root (hd0,1)
	kernel /vmlinuz-2.6.25-0.78.rc3.git1.fc9 ro root=/dev/md2
	initrd /initrd-2.6.25-0.78.rc3.git1.fc9.img

Regards,
   Dennis