Description of problem:
Software-RAID (md), LVM-rooted, FC5 x86_64 system panics upon boot after Yum
upgrades kernel to 2.6.18.  It can't find any volume groups.  Photo of panic:

    http://community.moertel.com/~thor/panic.png

If I revert back to the previous kernel, 2.6.17-1.2187_FC5, the system boots no
problem.

Version-Release number of selected component (if applicable):
2.6.18-1.2200.fc5 (x86_64 arch)

How reproducible:
Every time.

Steps to Reproduce:
1. Turn it on.
2. Watch it panic.
3. Take photo.  ;-)
  
Actual results:
Panic shortly after kernel decompresses and starts booting.

Expected results:
Kernel finds volume groups, mounts root, boots happily.

Additional info:
Opteron 165 (dual core) on a Tyan Tomcat K8E mobo, nVidia nFORCE 4 chipset, 4-GB
RAM.

# lspci
00:00.0 Memory controller: nVidia Corporation CK804 Memory Controller (rev a3)
00:01.0 ISA bridge: nVidia Corporation CK804 ISA Bridge (rev a3)
00:01.1 SMBus: nVidia Corporation CK804 SMBus (rev a2)
00:02.0 USB Controller: nVidia Corporation CK804 USB Controller (rev a2)
00:02.1 USB Controller: nVidia Corporation CK804 USB Controller (rev a3)
00:04.0 Multimedia audio controller: nVidia Corporation CK804 AC'97 Audio
Controller (rev a2)
00:06.0 IDE interface: nVidia Corporation CK804 IDE (rev f2)
00:07.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev f3)
00:08.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev f3)
00:09.0 PCI bridge: nVidia Corporation CK804 PCI Bridge (rev a2)
00:0b.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:0c.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:0d.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:0e.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron]
HyperTransport Technology Configuration
00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM
Controller
00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron]
Miscellaneous Control
01:05.0 Display controller: ATI Technologies Inc Rage XL (rev 27)
01:06.0 FireWire (IEEE 1394): VIA Technologies, Inc. IEEE 1394 Host Controller
(rev 80)
04:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5721 Gigabit
Ethernet PCI Express (rev 11)
05:00.0 VGA compatible controller: nVidia Corporation NV43 [GeForce 6600] (rev a2)

# mdadm /dev/md0   # /boot
/dev/md0: 101.88MiB raid1 2 devices, 1 spare. Use mdadm --detail for more detail.

# mdadm /dev/md1   # LVM PV
/dev/md1: 465.57GiB raid5 3 devices, 0 spares. Use mdadm --detail for more detail.

# pvscan
  PV /dev/md1   VG VolGroup00   lvm2 [465.56 GB / 32.00 MB free]
  Total: 1 [465.56 GB] / in use: 1 [465.56 GB] / in no VG: 0 [0   ]

# lvscan
  ACTIVE            '/dev/VolGroup00/LogVol00' [459.53 GB] inherit
  ACTIVE            '/dev/VolGroup00/LogVolSwap' [6.00 GB] inherit


# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                     466760872 235561348 207106852  54% /
/dev/md0                101018     15766     80036  17% /boot
/dev/shm               1734804         0   1734804   0% /dev/shm


See attachment for dmesg output under *previous* and working-just-fine kernel.