Bug 507648

Description of problem:
I have a SGI Altix XE server (a rebranded Supermicro) with one internal and one external LSI Logic SAS controller and a SW RAID on top of the internal disks. After the kernel (and probably mkinitrd) upgrade, the server cannot boot: grub loads the kernel, the kernel runs initrd, initrd loads the MPT driver module, the MPT driver correctly finds all the physical disks (both internal and external ones), but it fails to start the md0 device for the root filesystem.

I don't remember the exact error messages, but it is something like "/dev/sda does not contain a valid v0.90 superblock" (strange, because the md0 device is not directly on top of sda, it is on top of the sda1 partition). mdadm --examine /dev/sda1 under the older kernel reports the correct version 0.90.00 superblock.

Version-Release number of selected component (if applicable):
kernel-2.6.27.24-170.2.68.fc10.x86_64
mkinitrd-6.0.71-4.fc10.x86_64
nash-6.0.71-4.fc10.x86_64

How reproducible:
100 %

Steps to Reproduce:
1. have a server with these controllers:
# lspci|grep -i mpt
02:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068E PCI-Express Fusion-MPT SAS (rev 08)
07:02.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068 PCI-X Fusion-MPT SAS (rev 02)
2. create a md0 device on top of them
3. reboot
  
Actual results:
initrd finds all the physical disks, but fails to start the root MD device.

Expected results:
the server should boot as it did with the older kernel (and presumably the older mkinitrd).


Additional info:
Booting the older kernel (kernel-2.6.26.5-45.fc9.x86_64, initrd created 2008-10-21 09:17 in my case) works as expected.

I have another identical server which I don't want to reboot now, and it runs the 2.6.27.5-117.fc10.x86_64 kernel with an initrd created at 2008-12-02 18:01. So I think the problem has appeared in mkinitrd newer than that.

I have even tried to remove and reinstall the newest kernel package (thus re-creating initrd with the current mkinitrd), but it still does not work.