Red Hat Bugzilla – Bug 242765
[amd svm disabled] x86_64: kernel coredumps
Last modified: 2007-11-30 17:12:06 EST
Description of problem:
- I installed FC7 freshly. I choosed an xen kernel etc.
Hardware is an Dell optiplex 740 (AhtlonX2 / SATA etc.)
After installation i noticed that the normal kernel was
also installed. I rebooted the machine.
- Kernel core dumps on booting .
Normal kprintf-message are shown.
than init starts :
i see the "fedora welcome" string
i also see "press I for interactive mode" etc.
shortly after this, kernel core dumps.
i can read something about
"Process (udevd pid 496 , threadinfo etc. pp."
Notice: I can boot the kernel-xen !!
Version-Release number of selected component (if applicable):
Steps to Reproduce:
Reboot the system and boot kernel-2.6.21-1.3194.fc7
on a x86_64 machine (my is a dell optiplex 740)
Coredumps while init is starting udev
I can boot the kernel-xen !!
We need the exact messages from the screen. Please boot in 50-line mode (add the
kernel parameter "vga=ask" and select 80x50) then take a picture of the panic
with a digital camera. upload that as an attachment to this bugzilla.
Switching to vesa mode 80x50 doesnt help because
when INIT take the boot process they switch back
to, i dont know maybe 80x24 ?
Right now i haven't a camera here but i typed it down:
so no warranty
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000555555769e90 CR3: 000000007f310000 CR4: 00000000000006e0
Process udevd (pid: 496, threadinfo ffff81007fd6a000, task ffff81007ecff040)
Stack: ffffffff802582ac ffff810037c87f78 81007fea30000080 000000000000ffff
0000000000000000 ffffffff80221bf7 0000000000000000 0000000000000053
00000000000002ad ffffffff80257c76 ffff81007fd6bd60 <EOI> 0000000000000043
<IRQ> [<ffffffff802582ac>] call_softirq+0x1c/0x28
<From me: Without [< >]
<EOI> ffffffff8033190e __first_cpu+0x3/0x1f
Code: 0f30488b5620488b0a48c1e933 48 89 c8 48 c1 e8 09
RIP ffffffff8823932a : kvm_amd:svm_hardware_enable+0xa0/0x141
kernel panic - not syncing : aiee , killing interrupt handler!
JFYI: I can boot kernel-2.6.21-1.3xxx from FC7RC2 LiveCD !
I have tested this kernels:
kernel-2.6.21-1.3200.fc8 - doesnt work
kernel-2.6.21-1.3194.fc7 - doesnt work
i expected that at least this would work
because it is the same like the one on
kernel-2.6.21-1.3116.fc7 - doesnt work
kernel-2.6.20-1.3104.fc7 - doesnt work
kernel-xen-2.6.20-2925.9.fc7 - does work
udev is on f7 and fc7rc2 the same (106-4.fc7)
password --md5 $1$nz2jA0d7$qZGgWbA8bqopvb3eQPZbJ.
title Fedora (2.6.21-1.3116.fc7)
kernel /boot/vmlinuz-2.6.21-1.3116.fc7 ro root=LABEL=/
title CasaRoot (2.6.20-2925.9.fc7xen)
module /boot/vmlinuz-2.6.20-2925.9.fc7xen ro root=LABEL=/
(In reply to comment #2)
> Switching to vesa mode 80x50 doesnt help because
> when INIT take the boot process they switch back
> to, i dont know maybe 80x24 ?
Yeah, it loads the stupid default font and that forces it back to 80x25.
That can be disabled (the easy way) by renaming /lib/kbd/consolefonts
to something else during testing.
> Right now i haven't a camera here but i typed it down:
> so no warranty
> RIP ffffffff8823932a : kvm_amd:svm_hardware_enable+0xa0/0x141
> RSP ffff810037c87f68
You should be able to boot by blacklisting the kvm_amd module.
Edit /etc/modprobe.d/blacklist and add it.
I had kernel-2.6.21-1.3116.fc7 installed
i first modified /etc/modprobe.d/blacklist
then updated the kernel to kernel-2.6.21-1.3194.fc7
and rebooted - blacklisting kvm_amd doenst help.
i removed drivers/kvm dir, then i rebuild
the kernel dependencies and rebooted. This worked !!!
Being in 2.6.21-1.3194 i restored the drivers/kvm dir
and rebuilded the kernel dependencies again.
so - doing manualy modprobe kvm_amd killed the box.
for now - kvm_amd triggers these freezes.
so far - thank you - but one eye is crying because
i was planning to setup this box as a virt server ,)
Good Night (here is midnight)
The latest dev kernel (2.6.21-1.3218.fc8.x86_64)
also gets panic if i load the kvm-amd modul.
If virtualization is enabled in the BIOS, disable is.
If it is enabled, disable it :)
And let us know what happens.
About the BIOS: There is no possibility for change any
virtualization option. it dosnt offer it.
By the way - should we change the bug title - now where we
known what it caused?
Created attachment 158069 [details]
detect svm disabled by bios
The attached patch fixes this.
Patch went into kernel 3237
I tried kernel-2.6.21-1.3240.fc8.x86_64 and kernel-2.6.21-1.3228.fc7.x86_64.
The difference to the other tested kernels - it passes the point where init starts udev.
After booting - no kvm* module is loaded.
Loading kvm-amd manually ends in a kernel panic.
Patch is in kernel 1.3237.fc7
fc8 is following upstream and still doesn't have this fix.
Where to find 1.3237.fc7 kernel?
I searched in development/x86_64/os/Fedora/, updates/testing/7/x86_64/,
updates/7/x86_64/ and http://people.redhat.com/cebbert/kernels/!
(In reply to comment #13)
> Where to find 1.3237.fc7 kernel?
Not released, some kernel after 3237 will be released soon.
(In reply to comment #9)
> Created an attachment (id=158069) 
> detect svm disabled by bios
> The attached patch fixes this.
Avi, this patch is broken on 32-bit.
See bug #246250
Patch is in kernel 2.6.21-1.3255.fc7, in updates-testing now.
# uname -a
Linux casa.localdomain 2.6.21-1.3255.fc7 #1 SMP Thu Jul 5 18:03:06 EDT 2007 x86_64 x86_64
# modprobe kvm
# modprobe kvm-amd
kvm: disabled by bios
FATAL: Error inserting kvm_amd (/lib/modules/2.6.21-1.3255.fc7/kernel/drivers/kvm/kvm-amd.ko):
Operation not supported
# lsmod |head
Module Size Used by
kvm 75969 0
autofs4 32841 2
sunrpc 188329 1
ipv6 340289 16
cpufreq_ondemand 17489 1
dm_mirror 30209 0
dm_mod 69713 1 dm_mirror
video 28113 0
sbs 25729 0
Well as the message above stated - kvm stuff is unusable and no
bios options exists for enabling it.
Is it possible to bypass the bios and enabling it while booting?
There is no way to override the BIOS settings for svm. The patch is doing its
job and preventing a kernel crash when svm is disabled -- that's all it can do.
This appears to be still broken on kernel-22.214.171.124-65.fc7 - is this a new branch
that doesn't include the above fix?
2.6.21-1.3228.fc7 (which is before the fix) does boot, usually, but always
outputs a kernel traceback while starting udev. The newer kernel panics every time.
For anyone reading this who has an HP machine (dc5750 here with BIOS 2.20), I
found the BIOS option that controls virtualization technology - it's in Security
-> OS Security. Setting this to Enable fixes the oops.
There's a kvm-devel thread about the same problem (no patch, though):