It's been a while since this bug was updated. I'll mark it as incomplete for now. If the bug is fixed, please change the status to "Fix Released". If the bug still exists, please change the status to "Confirmed".
** Changed in: linux (Ubuntu Saucy) Status: In Progress => Incomplete -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1181315 Title: unregister_netdevice: waiting for lo to become free. Usage count = 2' is reported and causing kernel hang when floodlight tests are run using utah Status in “linux” package in Ubuntu: Incomplete Status in “linux” source package in Saucy: Incomplete Bug description: When utah client is used to run floodlight smoke tests for saucy server images, the following error is reported. May 17 17:41:13 ubuntu kernel: [ 618.483362] IPv6: ADDRCONF(NETDEV_UP): s1-eth1: link is not ready May 17 17:41:23 ubuntu kernel: [ 628.220062] unregister_netdevice: waiting for lo to become free. Usage count = 2 May 17 17:41:33 ubuntu kernel: [ 638.460029] unregister_netdevice: waiting for lo to become free. Usage count = 2 .... ... ... May 17 17:44:16 ubuntu kernel: [ 801.760026] unregister_netdevice: waiting for lo to become free. Usage count = 2 May 17 17:44:27 ubuntu kernel: [ 812.000029] unregister_netdevice: waiting for lo to become free. Usage count = 2 May 17 17:44:37 ubuntu kernel: [ 822.240031] unregister_netdevice: waiting for lo to become free. Usage count = 2 May 17 17:44:47 ubuntu kernel: [ 832.480024] unregister_netdevice: waiting for lo to become free. Usage count = 2 May 17 17:44:55 ubuntu kernel: [ 840.564053] INFO: task mnexec:9343 blocked for more than 120 seconds. May 17 17:44:55 ubuntu kernel: [ 840.564268] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. May 17 17:44:55 ubuntu kernel: [ 840.564494] mnexec D ffff88003fc14240 0 9343 8358 0x00000000 May 17 17:44:55 ubuntu kernel: [ 840.564498] ffff880036c3fe20 0000000000000046 ffff880036c3ffd8 0000000000014240 May 17 17:44:55 ubuntu kernel: [ 840.564501] ffff880036c3ffd8 0000000000014240 ffff88003c1add40 ffffffff81ccea60 May 17 17:44:55 ubuntu kernel: [ 840.564503] ffff88003c1add40 ffffffff81ccea64 00000000ffffffff ffffffff81ccea68 May 17 17:44:55 ubuntu kernel: [ 840.564506] Call Trace: May 17 17:44:55 ubuntu kernel: [ 840.564531] [<ffffffff816d1499>] schedule_preempt_disabled+0x29/0x70 May 17 17:44:55 ubuntu kernel: [ 840.564535] [<ffffffff816cf537>] __mutex_lock_slowpath+0xe7/0x160 May 17 17:44:55 ubuntu kernel: [ 840.564550] [<ffffffff8117cbcf>] ? __kmalloc+0x14f/0x180 May 17 17:44:55 ubuntu kernel: [ 840.564554] [<ffffffff816cefbf>] mutex_lock+0x1f/0x30 May 17 17:44:55 ubuntu kernel: [ 840.564564] [<ffffffff815c5e05>] copy_net_ns+0x65/0x100 May 17 17:44:55 ubuntu kernel: [ 840.564574] [<ffffffff810814e9>] create_new_namespaces+0xf9/0x180 May 17 17:44:55 ubuntu kernel: [ 840.564577] [<ffffffff81081731>] unshare_nsproxy_namespaces+0x61/0xa0 May 17 17:44:55 ubuntu kernel: [ 840.564582] [<ffffffff81057b41>] sys_unshare+0x181/0x2a0 May 17 17:44:55 ubuntu kernel: [ 840.564585] [<ffffffff816da99d>] system_call_fastpath+0x1a/0x1f ================================================ This is observed to occur only when utah is used to run the floodlight smoke tests. Running the floodlight tests without utah does not cause this issue and using utah to run some other tests does not cause this issue either. Noticed a similar bug 1021471, but this one is occurring in KVM using libvirt. The issue is only with the saucy kernel versions, 3.9.0-1 onwards and does not occur with 3.9.0-0. The tests were tried with saucy server VMs on precise as well as saucy hosts and the results is the same. ================ Steps to reproduce: 1. Install a default saucy server on a vm (either manually or preseeded default installation) with either i386 or amd64 image using KVM, libvirt 2. Do the following to install utah inside the VM sudo apt-add-repository -y ppa:utah/stable sudo apt-get update sudo apt-get install utah 3. Run the floodlight tests using sudo utah -r lp:ubuntu-test-cases/server/runlists/floodlight.run 4. Now "kernel: [ 358.452029] unregister_netdevice: waiting for lo to become free. Usage count = 2" will be continuously reported The impacted jobs are, https://jenkins.qa.ubuntu.com/view/Saucy/view/Smoke%20Testing/job/saucy-server-amd64-smoke-floodlight/15/ and https://jenkins.qa.ubuntu.com/view/Saucy/view/Smoke%20Testing/job/saucy-server-i386-smoke-floodlight/13/ ProblemType: Bug DistroRelease: Ubuntu 13.10 Package: linux-image-3.9.0-2-generic 3.9.0-2.6 ProcVersionSignature: Ubuntu 3.9.0-2.6-generic 3.9.2 Uname: Linux 3.9.0-2-generic x86_64 AlsaVersion: Advanced Linux Sound Architecture Driver Version k3.9.0-2-generic. AplayDevices: Error: [Errno 2] No such file or directory: 'aplay' ApportVersion: 2.10.1-0ubuntu1 Architecture: amd64 ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord' AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/by-path', '/dev/snd/controlC0', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D0c', '/dev/snd/pcmC0D0p', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: CRDA: Error: [Errno 2] No such file or directory: 'iw' Card0.Amixer.info: Error: [Errno 2] No such file or directory: 'amixer' Card0.Amixer.values: Error: [Errno 2] No such file or directory: 'amixer' Date: Fri May 17 17:53:02 2013 HibernationDevice: RESUME=UUID=a9b2a509-9179-44d3-a4ea-807f7cd05d4e InstallationDate: Installed on 2013-05-17 (0 days ago) InstallationMedia: Ubuntu-Server 13.10 "Saucy Salamander" - Alpha amd64 (20130517) Lsusb: Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub MachineType: Bochs Bochs MarkForUpload: True ProcFB: ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.9.0-2-generic root=UUID=810403bd-1b5c-4a51-bc07-6ce34be38cd9 nomodeset ro RelatedPackageVersions: linux-restricted-modules-3.9.0-2-generic N/A linux-backports-modules-3.9.0-2-generic N/A linux-firmware 1.108 RfKill: Error: [Errno 2] No such file or directory: 'rfkill' SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 01/01/2011 dmi.bios.vendor: Bochs dmi.bios.version: Bochs dmi.chassis.type: 1 dmi.chassis.vendor: Bochs dmi.modalias: dmi:bvnBochs:bvrBochs:bd01/01/2011:svnBochs:pnBochs:pvr:cvnBochs:ct1:cvr: dmi.product.name: Bochs dmi.sys.vendor: Bochs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1181315/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp