== SRU Justification == Copying a fairly large amount of data over the network inside a container and then exiting the container can trigger a missing decrement in the per cpu reference count on a network device. The result is the kernel error message:
unregister_netdevice: waiting for lo to become free. Usage count = 1 ..and the next time lxc-start is started it just hangs. == Fix == The following upstream commit 3d861f661006606bf159fd6bd973e8 fixes this issue by releasing all possible references to linked objects. == Impact == Users copying large amounts of data over the network inside a container can trigger this bug and cannot exit the container and restart it. == Test Case == To trigger the bug: On the host: 1. sudo lxc-create -n test01 -t ubuntu -- -a amd64 -r quantal 2. sudo lxc-start -n test01 3. Login with ubuntu/ubuntu Inside the container: 4. Copy an amount of data from the network (scp from your local network or wget below) 4.1 sudo apt-get update && sudo apt-get -y install wget 4.2 wget cdimage.ubuntu.com/daily-live/current/quantal-desktop-amd64.iso 5. Download more than 250MB and press CTRL+C 6. sudo poweroff On the host: After a few seconds one will see the kernel warning appear: unregister_netdevice: waiting for lo to become free. Usage count = 1 7. sudo lxc-start -n test01 ..and this will hang. With the fix, the error message will not occur and step 7 will not hang. One can run lxc-start and then exit the container multiple times without it hanging -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1065434 Title: "unregister_netdevice: waiting for lo to become free. Usage count = 1" after LXC container shutdown To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1065434/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
