loading X during xenU startup may reboot machine

[Msquared]

The most likely setup to cause this is when you have set up xenU domains
to start during boot by turning xendomains on, and your dom0 domain (your
main domain) is set to start X.


I installed FC4 onto two drives.  I use one for dom0 and the other for a
domU, and if I start the domU domain manually or via 'service xendomains
start' everything works fine.

I ran 'chkconfig xendomains on', restarted, and started to see problems.

The problem is the machine reboots itself when trying to start up the auto
xendomains.  The following output appears on the Xen console just before
the machine is rebooted:

    ****************************************
    CPU0 FATAL PAGE FAULT
    [error_code=0000]
    Faulting linear address might be f000f0af
    Aieee! CPU0 is toast...
    ****************************************

    Reboot in five seconds...

(See below for full dump)


The problem appears to go away if I boot dom0 into console (runlevel 3)
mode instead of gui (runlevel 5) mode.  It doesn't seem to matter whether
domU is started in console or gui mode.

If I boot dom0 into console mode but switch to gui mode while domU is
starting up, the problem persists.  Further testing reveals that the
problem occurs even when starting up domU manually (xm create) rather than
automatically (xendomains init script).

Regards, Msquared...

Here is the full dump from Xen:

(XEN) CPU:    0
(XEN) EIP:    0808:[<ff108bb7>]      
(XEN) EFLAGS: 00010202   CONTEXT: hypervisor
(XEN) eax: 0000009c   ebx: 00000090   ecx: 00000000   edx: 00000000
(XEN) esi: f000f0a7   edi: ffbef090   ebp: 0000001a   esp: ff103da4
(XEN) ds: 0810   es: 0810   fs: 0810   gs: 0810   ss: 0810   cs: 0808
(XEN) Stack trace from ESP=ff103da4:
(XEN)    1306e000 27fe0000 27fe0001 [ff11bd05] 00000024 ffbf9980 00000000 00000000 
(XEN)    00000001 fc400000 ffbf9080 [ff11b1d3] ff17fc00 ffbf9080 00000000 00000000 
(XEN)    ff17fc00 00000808 00000246 00000067 000252ae 00000000 00000000 [ff11c2a5] 
(XEN)    00000067 ffbf9080 00000000 c463a8dc 00000000 00000067 ffbf9080 [ff133b99] 
(XEN)    ff103eec c463a8dc 0c63a061 c01594cd 0000004e 00000087 00000000 [ff135124] 
(XEN)    00000004 00000001 00000000 00000004 ff103ec3 00000002 fc400000 80000002 
(XEN)    [ff11c012] fc400000 e0000000 00004e00 fee01807 00000027 00000000 ffbf9080 
(XEN)    00000004 00000001 00000000 00000004 05be0000 00007ff1 40000000 00000000 
(XEN)    00000000 55555555 c463a8dc 00000067 b7e37000 00000000 000e0003 c01594cd 
(XEN)    00000061 00010246 c5263ec4 00000069 0000007b 0000007b 00000000 00000033 
(XEN)    00000001 00000004 00000000 00000067 c463a8dc 00000000 00000004 00000000 
(XEN)    00000000 ff103eb0 ffffffff 0000003e 00000000 00000001 00000001 ffbf9080 
(XEN)    c463a8dc 00000000 0000c63a [ff11da5e] ff103fb8 c463a8dc ff1561e8 00000004 
(XEN)    [ff10d9d1] 00000000 ffbf9280 fe3f8b7c 00000000 fe3118e8 000002df [ff12bc93] 
(XEN)    ff103fb8 ffbf8080 0c63a061 ffbf9080 c463a8dc ffbf8080 ff103fb8 [ff12b62b] 
(XEN)    ffbf9080 c463a8dc 00000007 c01f95f0 c034991c 000001fb c5263f2c ffbf8080 
(XEN)    c463a8dc 00000000 b7e37000 [ff136b4e] ff103fb8 00000000 00000000 55555555 
(XEN)    c463a8dc 00000000 b7e37000 00000000 000e0003 c01594cb 00000061 00010246 
(XEN)    c5263ec4 00000069 0000007b 0000007b 00000000 00000033 ffbf8080 
(XEN) Call Trace from ESP=ff103da4:
(XEN)    [<ff11bd05>] [<ff11b1d3>] [<ff11c2a5>] [<ff133b99>] [<ff135124>] [<ff11c012>] 
(XEN)    [<ff11da5e>] [<ff10d9d1>] [<ff12bc93>] [<ff12b62b>] [<ff136b4e>] 

****************************************
CPU0 FATAL PAGE FAULT
[error_code=0000]
Faulting linear address might be f000f0af
Aieee! CPU0 is toast...
****************************************

Reboot in five seconds...