Re: [Qemu-devel] Bug#688964: qemu-kvm: Fedora 17 guest hangs on boot with soft lockup in udevd

[Nikolai Kondrashov <spbnick@gmail.com>]

On 09/27/2012 08:15 PM, Michael Tokarev wrote:
> Ok.  I reproduced this, I _think_, and now I want some confirmation
> from you.  This is my command line:
>
>    QEMU_AUDIO_DRV=none qemu-kvm -nodefconfig -nodefaults -enable-kvm \
>     -monitor stdio -rtc base=utc \
>     -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 \
>     -m 512 -vga cirrus -cdrom Fedora-17-x86_64-Live-Desktop.iso \
>     -device intel-hda,id=sound0,bus=pci.0,addr=0x4 \
>     -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0
>
> leads to this in guest:
>
> ...
> Starting udev Wait for Complete Device Initialization...
> [    4.123978] piix4_smbus 0000:00:01.3: SMBus Host Controller at 0xb100, revision 0
> [    4.311473] microcode: AMD CPU family 0x6 not supported
> [    4.355429] microcode: AMD CPU family 0x6 not supported
> [    7.323032] ALSA sound/pci/hda/hda_intel.c:823 azx_get_response timeout, switching to polling mode: last cmd=0x000f0000
> [    8.325018] ALSA sound/pci/hda/hda_intel.c:831 No response from codec, disabling MSI: last cmd=0x000f0000
> [   36.055021] BUG: soft lockup - CPU#0 stuck for 22s! [udevd:385]
>
> Is it the issue you're seeing?
>
> Removing hda-duplex device lets it to work.  Removing piix3-usb-uhci
> allows it to boot too.  Even removing the explicit bus address from
> piix3-usb-uhci allow it to boot.
>
> Nikolai, please verify if this is the issue you're seeing, and
> please try without sound device.  If this is the case, let's
> downgrade this bug from important to normal, since emulated sound
> devices aren't really of high priority in this context, and there
> should be easy workaround (to disable sound).

I wasn't able to get a backtrace, unfortunately. It just isn't printed. 
Could
I be missing some trick? However, removing the sound device did help.

I'll try the patch you sent in another message next.

Thank you.