KVM hangs after KERNEL BUG (tun.c)

Binary package hint: qemu-kvm

VM machines stops working after some time. dmesg is attached.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: kvm 1:84+dfsg-0ubuntu16+0.12.3+noroms+0ubuntu6
ProcVersionSignature: Ubuntu 2.6.32-20.30-server 2.6.32.11+drm33.2
Uname: Linux 2.6.32-20-server x86_64
Architecture: amd64
Date: Thu Apr 15 14:56:33 2010
EcryptfsInUse: Yes
InstallationMedia: Ubuntu-Server 10.04 "Lucid Lynx" - Alpha amd64 (20100114)
KvmCmdLine:
 UID PID PPID C SZ RSS PSR STIME TTY TIME CMD
 root 2534 1 0 180800 203236 0 Apr13 ? 00:07:25 /usr/bin/kvm -S -M pc-0.12 -cpu qemu32 -enable-kvm -m 512 -smp 1 -name FIREBIRD -uuid be07ef9c-bd1b-9cdc-1cff-53f4d491454d -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/FIREBIRD.monitor,server,nowait -monitor chardev:monitor -boot c -drive file=/dev/storage/linux-firebird,if=virtio,index=0,boot=on,format=raw -drive if=ide,media=cdrom,index=2 -net nic,macaddr=52:54:00:2e:48:bf,vlan=0,model=virtio,name=virtio.0 -net tap,fd=68,vlan=0,name=tap.0 -chardev pty,id=serial0 -serial chardev:serial0 -parallel none -usb -vnc 127.0.0.1:0 -vga cirrus
 root 2610 1 21 0 0 4 Apr13 ? 10:03:12 [kvm] <defunct>
 root 2639 1 6 307884 1068588 4 Apr13 ? 02:56:42 /usr/bin/kvm -S -M pc-0.12 -enable-kvm -m 1024 -smp 1 -name W2003 -uuid d06cc56c-779e-a9a5-475f-5e1044e59c01 -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/W2003.monitor,server,nowait -monitor chardev:monitor -localtime -boot d -drive file=/dev/mirror/win-2003,if=ide,index=0,format=raw -drive file=/iso-windows/W2003-B943W-J6WFM-6YKC7-VDW2D-K6YQY.iso,if=ide,media=cdrom,index=2 -net nic,macaddr=52:54:00:0e:78:4f,vlan=0,name=nic.0 -net tap,fd=72,vlan=0,name=tap.0 -chardev pty,id=serial0 -serial chardev:serial0 -parallel none -usb -usbdevice tablet -vnc 127.0.0.1:2 -vga cirrus
MachineType: Intel Corporation S5520HC
ProcCmdLine: BOOT_IMAGE=/vmlinuz-2.6.32-20-server root=/dev/mapper/mirror-linux--root ro quiet splash
ProcEnviron:
 LANGUAGE=pt_BR:pt:pt_PT
 PATH=(custom, no user)
 LANG=pt_BR.utf8
 SHELL=/bin/bash
SourcePackage: qemu-kvm
dmi.bios.date: 03/02/2009
dmi.bios.vendor: Intel Corp.
dmi.bios.version: S5500.86B.01.10.0025.030220091519
dmi.board.asset.tag: ....................
dmi.board.name: S5520HC
dmi.board.vendor: Intel Corporation
dmi.board.version: FRU Ver 0.05
dmi.chassis.asset.tag: ....................
dmi.chassis.type: 17
dmi.chassis.vendor: ..............................
dmi.chassis.version: ..................
dmi.modalias: dmi:bvnIntelCorp.:bvrS5500.86B.01.10.0025.030220091519:bd03/02/2009:svnIntelCorporation:pnS5520HC:pvr....................:rvnIntelCorporation:rnS5520HC:rvrFRUVer0.05:cvn..............................:ct17:cvr..................:
dmi.product.name: S5520HC
dmi.product.version: ....................
dmi.sys.vendor: Intel Corporation