** Changed in: linux (Ubuntu Hardy)
Status: In Progress => Fix Released
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https://bugs.launchpad.net/bugs/458521
Title:
kvm crash when using virtio for network, hardy guest
Status in QEMU:
Fix Released
Status in Release Notes for Ubuntu:
Fix Released
Status in “linux” package in Ubuntu:
Fix Released
Status in “qemu-kvm” package in Ubuntu:
Fix Released
Status in “linux” source package in Hardy:
Fix Released
Status in “qemu-kvm” source package in Hardy:
Invalid
Status in “linux” source package in Karmic:
Fix Released
Status in “qemu-kvm” source package in Karmic:
Fix Released
Bug description:
Binary package hint: kvm
I was running a kvm host with 5 virtual machines using jaunty. 1
running centos 5.4, 3 running karmic and 1 running hardy.
I upgraded the host to karmic to test it and one of my virtual
machines(the vm with hardy) crashs after some seconds of boot! I stack
traced the kvm process and found a "virtio-net truncating packet"
before process crash.
No error in any log file. The VM just crash.
I changed the model of network interface(the disk is still virtio) in
VM.xml to rtl8139, redefined and started. The problem goes away.
I don't know if it's a kvm bug or libvirt(regarding the bridge
network) bug but definitely is a bug. All other VMs are running OK
with virtio for both network and disk.
===========================
Karmic Release Notes:
KVM Guest Crashes when Guest is Hardy and using Virtio Networking
Ubuntu 8.04 LTS (Hardy) KVM guests using virtio networking may crash,
when running on top of Ubuntu 9.10 (Karmic) hosts.
As a workaround, such guests should use either e1000 or rtl839 as the
networking model. A fix for the bug is currently in progress and
should be addressed in an update to the qemu-kvm package in Karmic.
===========================
===========================
SRU Justification
This bug is a regression from the kvm-84 package in 9.04. Karmic users
hosting 8.04 KVM guests and using virtio networking *will* crash their VM when
the network connection is saturated. As the virtual machine crashes without
sync buffers, there could very well be data lost in the guest filesystem or
memory.
I have posted the patch for review, and acked upstream:
* http://lists.gnu.org/archive/html/qemu-devel/2009-10/msg02495.html
I am bundling this fix with two other minor fixes, for Bug #452323 and Bug
#453441.
TEST CASE:
1) Download and uncompress
* http://rookery.canonical.com/~kirkland/hardy.img.bz2
2) Download a bridged networking script
* http://rookery.canonical.com/~kirkland/bridge.sh
3) Start the vm with virtio and bridged networking
* sudo /usr/bin/kvm -m 512 -net nic,model=virtio -net tap,script=bridge.sh
-drive file=hardy.img,if=virtio,index=0,boot=on
4) The VM's username and password are both "ubuntu".
5) In the guest, have nc listen on a port
* nc -lp 1234 > /dev/null
6) On your host, flood the guest with network traffic on that port
* cat /dev/urandom | nc -w 3 guest_ip 1234
7) Without this fix, the guest will crash immediately, saying:
* virtio-net truncating packet
8) With the fix, you will be able to send the guest with data over the
virtio network ad nauseum. I get about 6MB/s throughput.
===========================
