F10a xen crashes on boot

[John Summerfield]

Bugz https://bugzilla.redhat.com/show_bug.cgi?id=458808

xen crashes with these messages:
xen_init_pt returned.
(XEN) traps.c:1838:d0 Attempt to change unmodifiable CR0 flags.
(XEN) traps.c:413:d0 Unhandled general protection fault fault/trap [#13]
on VCPU
0 [ec=0000]
(XEN) domain_crash_sync called from entry.S
(XEN) Domain 0 (vcpu#0) crashed on cpu#0:
(XEN) ----[ Xen-3.2.0  x86_64  debug=n  Tainted:    C ]----
(XEN) CPU:    0
(XEN) RIP:    e033:[<ffffffff8020b385>]
(XEN) RFLAGS: 0000000000000206   CONTEXT: guest
(XEN) rax: 00000000c0050033   rbx: 0000000000000000   rcx: 0000000000000000
(XEN) rdx: ffffffff806925b0   rsi: 0000000000000000   rdi: 00000000c0050033
(XEN) rbp: ffffffff80639e38   rsp: ffffffff80639df0   r8:  0000000000000002
(XEN) r9:  0000000000000070   r10: 0000000000000000   r11: ffffffff80639f2c
(XEN) r12: ffffffff80639ef4   r13: 0000000000000210   r14: 0000000000000070
(XEN) r15: 0000000000000000   cr0: 000000008005003b   cr4: 00000000000026b0
(XEN) cr3: 0000000078201000   cr2: 0000000000000000
(XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: e02b   cs: e033
(XEN) Guest stack trace from rsp=ffffffff80639df0:
(XEN)    0000000000000000 ffffffff80639f2c 0000000000000000 ffffffff8020b385
(XEN)    000000010000e030 0000000000010006 ffffffff80639e38 000000000000e02b
(XEN)    ffffffff80639ef4 ffffffff80639e88 ffffffff8021c2e1 0000000000000000
(XEN)    0000000000000000 ffffffff80639f38 00000000804a8a5f 0000000000000008
(XEN)    0000000000000000 ffffffff80639ef4 0000000000000210 ffffffff80639f18
(XEN)    ffffffff80645ee1 0000000000074110 0000000000000001 00000000000003e0
(XEN)    00000000805e1070 0000000000000000 ffffffff80639f18 ffffffff80256190
(XEN)    ffffffff80639f18 ffffffff80256aeb 0000000000000000 ffffffff80639f18
(XEN)    00000000806514f7 ffffffff80639f34 ffffffff80639f30 ffffffff80639f2c
(XEN)    ffffffff80639f28 ffffffff80639f58 ffffffff8064594b 0000000000000000
(XEN)    0000302400000000 ffffffff80639fb0 ffffffff80667390 ffffffffffffffff
(XEN)    0000000000000000 ffffffff80639f98 ffffffff80642f91 ffffffff80639f88
(XEN)    ffffffff80250b5c 0000000000000000 ffffffff80667390 ffffffffffffffff
(XEN)    0000000000000000 ffffffff80639fd8 ffffffff8063ba43 ffffffff80639fc8
(XEN)    ffffffff80669840 0000000000c33918 0000000000000000 0000000000000000
(XEN)    0000000000000000 ffffffff80639ff8 ffffffff80641cfc 0000000000000000
(XEN)    0000000000000000 0000000000000000 0000000000000000 00cf9b000000ffff
(XEN)    00af9b000000ffff 00cf93000000ffff 00cffb000000ffff 00cff3000000ffff
(XEN)    00affb000000ffff 0000000000000000 0000000000000000 0000000000000000
(XEN)    0000000000000000 0000000000000000 0000000000000000 0000000000000000
(XEN) Debugging connection not set up.
(XEN) Domain 0 crashed: rebooting machine in 5 seconds.

This is the relevant menu entry:
title Fedora (2.6.26-0.1.rc6.git2.fc10.x86_64.xen)
         root (hd0,4)
         kernel /xen.gz-2.6.26-0.1.rc6.git2.fc10.x86_64.xen
com1=115200,8n1 conso
le=com1 `xencons=ttyS sync_console
#       kernel /xen.gz-2.6.26-0.1.rc6.git2.fc10.x86_64.xen
vga=text-80x60 com1=1
15200,8n1
         module /vmlinuz-2.6.26-0.1.rc6.git2.fc10.x86_64.xen ro
root=/dev/VolGrou
p00/LogVol00 vga=794 video=vesafb selinux=0 console=ttyS0,115200n8
console=tty
         savedefault
         module /initrd-2.6.26-0.1.rc6.git2.fc10.x86_64.xen.img

The system was fully up2date this morning, my time.

Has anyone not had this with this kernel (surely it's not very dependent
on the CPU, an Intel(R) Core(TM)2 CPU          6300  @ 1.86GHz.