I can test that. I had to use the hardware to deal with a separate issue but I loaded up the backported package on Friday and I have been running a test over the weekend. No problems yet. 

Sent from my iPhone

On Sep 3, 2012, at 1:21 AM, Soren Hansen <email address hidden> wrote:

> As Serge says, we think we've narrowed in on the set of commits that
> will address this problem:
> 
>   a821ce5 virtio: order index/descriptor reads
>   92045d8 virtio: add missing mb() on enable notification
>   a281ebc virtio: add missing mb() on notification
> 
> I'd be happy to provide a SRU candidate in a PPA with just those patches
> applied if anyone is willing to test?
> 
> Serge, would it be ok for me to use the ubuntu-virt/backports ppa for
> this, or would you rather I create a new PPA?
> 
> -- 
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/997978
> 
> Title:
>  KVM images lose connectivity with bridged network
> 
> Status in OpenStack Compute (Nova):
>  New
> Status in “bridge-utils” package in Ubuntu:
>  Invalid
> Status in “ifenslave” package in Ubuntu:
>  Confirmed
> Status in “libvirt” package in Ubuntu:
>  Confirmed
> Status in “linux” package in Ubuntu:
>  Confirmed
> Status in “qemu-kvm” package in Ubuntu:
>  Confirmed
> 
> Bug description:
>  System:
>  -----------
>  Dell R410 Dual processor 2.4Ghz w/16G RAM
>  Distributor ID: Ubuntu
>  Description:    Ubuntu 12.04 LTS
>  Release:        12.04
>  Codename:       precise
> 
>  Setup:
>  ---------
>  We're running 3 KVM guests, all Ubuntu 12.04 LTS using bridged networking. 
> 
>  From the host:
>  # cat /etc/network/interfaces
>  auto br0
>  iface br0 inet static
>          address 212.XX.239.98
>          netmask 255.255.255.240
>          gateway 212.XX.239.97
>          bridge_ports eth0
>          bridge_fd 9
>          bridge_hello 2
>          bridge_maxage 12
>          bridge_stp off
> 
>  # ifconfig eth0
>  eth0      Link encap:Ethernet  HWaddr d4:ae:52:84:2d:5a  
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:11278363 errors:0 dropped:3128 overruns:0 frame:0
>            TX packets:14437384 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:1000 
>            RX bytes:4115980743 (4.1 GB)  TX bytes:5451961979 (5.4 GB)
>            Interrupt:36 Memory:da000000-da012800 
> 
>  # ifconfig br0
>  br0       Link encap:Ethernet  HWaddr d4:ae:52:84:2d:5a  
>            inet addr:212.XX.239.98  Bcast:212.XX.239.111  Mask:255.255.255.240
>            inet6 addr: fe80::d6ae:52ff:fe84:2d5a/64 Scope:Link
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:1720861 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:1708622 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:0 
>            RX bytes:210152198 (210.1 MB)  TX bytes:300858508 (300.8 MB)
> 
>  # brctl show
>  bridge name     bridge id               STP enabled     interfaces
>  br0             8000.d4ae52842d5a       no              eth0
> 
>  I have no default network configured to autostart in libvirt as we're using bridged networking:
>  # virsh net-list --all
>  Name                 State      Autostart
>  -----------------------------------------
>  default              inactive   no        
> 
>  # arp
>  Address                  HWtype  HWaddress           Flags Mask            Iface
>  mailer03.xxxx.com       ether   52:54:00:82:5f:0f   C                     br0
>  mailer01.xxxx.com       ether   52:54:00:d2:f7:31   C                     br0
>  mailer02.xxxx.com       ether   52:54:00:d3:8f:91   C                     br0
>  dxi-gw2.xxxx.com        ether   00:1a:30:2a:b1:c0   C                     br0
> 
>  From one of the guests:
>  <domain type='kvm' id='4'>
>    <name>mailer01</name>
>    <uuid>d41d1355-84e8-ae23-e84e-227bc0231b97</uuid>
>    <memory>2097152</memory>
>    <currentMemory>2097152</currentMemory>
>    <vcpu>1</vcpu>
>    <os>
>      <type arch='x86_64' machine='pc-1.0'>hvm</type>
>      <boot dev='hd'/>
>    </os>
>    <features>
>      <acpi/>
>    </features>
>    <clock offset='utc'/>
>    <on_poweroff>destroy</on_poweroff>
>    <on_reboot>restart</on_reboot>
>    <on_crash>destroy</on_crash>
>    <devices>
>      <emulator>/usr/bin/kvm</emulator>
>      <disk type='file' device='disk'>
>        <driver name='qemu' type='raw'/>
>        <source file='/dev/mapper/vg_main-mailer01--root'/>
>        <target dev='hda' bus='ide'/>
>        <alias name='ide0-0-0'/>
>        <address type='drive' controller='0' bus='0' unit='0'/>
>      </disk>
>      <disk type='file' device='disk'>
>        <driver name='qemu' type='raw'/>
>        <source file='/dev/mapper/vg_main-mailer01--swap'/>
>        <target dev='hdb' bus='ide'/>
>        <alias name='ide0-0-1'/>
>        <address type='drive' controller='0' bus='0' unit='1'/>
>      </disk>
>      <controller type='ide' index='0'>
>        <alias name='ide0'/>
>        <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
>      </controller>
>      <interface type='bridge'>
>        <mac address='52:54:00:d2:f7:31'/>
>        <source bridge='br0'/>
>        <target dev='vnet0'/>
>        <model type='virtio'/>
>        <alias name='net0'/>
>        <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
>      </interface>
>      <serial type='pty'>
>        <source path='/dev/pts/0'/>
>        <target port='0'/>
>        <alias name='serial0'/>
>      </serial>
>      <console type='pty' tty='/dev/pts/0'>
>        <source path='/dev/pts/0'/>
>        <target type='serial' port='0'/>
>        <alias name='serial0'/>
>      </console>
>      <input type='mouse' bus='ps2'/>
>      <graphics type='vnc' port='5900' autoport='yes' listen='127.0.0.1'>
>        <listen type='address' address='127.0.0.1'/>
>      </graphics>
>      <video>
>        <model type='cirrus' vram='9216' heads='1'/>
>        <alias name='video0'/>
>        <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
>      </video>
>      <memballoon model='virtio'>
>        <alias name='balloon0'/>
>        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
>      </memballoon>
>    </devices>
>    <seclabel type='dynamic' model='apparmor' relabel='yes'>
>      <label>libvirt-d41d1355-84e8-ae23-e84e-227bc0231b97</label>
>      <imagelabel>libvirt-d41d1355-84e8-ae23-e84e-227bc0231b97</imagelabel>
>    </seclabel>
>  </domain>
> 
>  From within the guest:
>  # cat /etc/network/interfaces 
>  # The primary network interface
>  auto eth0
>  iface eth0 inet static
>          address 212.XX.239.100
>          netmask 255.255.255.240 
>          network 212.XX.239.96
>          broadcast 212.XX.239.111
>          gateway 212.XX.239.97
> 
>  # ifconfig
>  eth0      Link encap:Ethernet  HWaddr 52:54:00:d2:f7:31  
>            inet addr:212.XX.239.100  Bcast:212.XX.239.111  Mask:255.255.255.240
>            inet6 addr: fe80::5054:ff:fed2:f731/64 Scope:Link
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:5631830 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:6683416 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:1000 
>            RX bytes:2027322829 (2.0 GB)  TX bytes:2076698690 (2.0 GB)
> 
> 
>  A commandline which starts the KVM guest:
>  /usr/bin/kvm -S -M pc-1.0 -enable-kvm -m 2048 -smp 1,sockets=1,cores=1,threads=1 -name mailer01 -uuid d41d1355-84e8-ae23-e84e-227bc0231b97 -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/mailer01.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -drive file=/dev/mapper/vg_main-mailer01--root,if=none,id=drive-ide0-0-0,format=raw -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -drive file=/dev/mapper/vg_main-mailer01--swap,if=none,id=drive-ide0-0-1,format=raw -device ide-drive,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1 -netdev tap,fd=18,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:d2:f7:31,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -usb -vnc 127.0.0.1:0 -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4
> 
>  Problem:
>  ------------
>  Periodically (at least once a day), one or more of the guests lose network connectivity.  Ping responds with 'host unreachable', even from the dom host. Logging in via the serial console shows no problems: eth0 is up, can ping the local host, but no outside connectivity.  Restart the network (/etc/init.d/networking restart) does nothing. Reboot the machine and it comes alive again.
> 
>  I've verified there's no arp games going on on the primary host (the
>  arp tables remain the same before - when it had connectivity - and
>  after - when it doesn't.
> 
>  This is a critical issue affecting production services on the latest
>  LTS release of Ubuntu. It's similar to an issue which was 'resolved'
>  in 10.04 but appears to have risen its ugly head again.
> 
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/nova/+bug/997978/+subscriptions
>