We also backported [1] to 4.2 (linux-lts-wily) and deployed it to our production OpenStack cloud. We just installed it yesterday and our MTBF is between two and twenty days, so we won't know if this has made any difference for a while now.
Some details about our configuration / failure mode: Three OpenStack "Layer 3" hosts (running 3.19.0-30-generic #34~14.04.1-Ubuntu) providing virtual routers/VPNs/Metadata via network namespaces. Our most recent failures occurred on hosts B and C (within 30 minutes of each other, after having been fine for weeks) while removing routers from A and re-creating them on B and C. Our stack traces are a slightly different from the ones posted above... Dec 14 15:37:05 hostname kernel: [961050.119727] INFO: task ip:9865 blocked for more than 120 seconds. Dec 14 15:37:05 hostname kernel: [961050.126707] Tainted: G C 3.19.0-30-generic #34~14.04.1-Ubuntu Dec 14 15:37:05 hostname kernel: [961050.135073] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Dec 14 15:37:05 hostname kernel: [961050.144094] ip D ffff88097e3e3de8 0 9865 9864 0x00000000 Dec 14 15:37:05 hostname kernel: [961050.144098] ffff88097e3e3de8 ffff880e982693a0 0000000000013e80 ffff88097e3e3fd8 Dec 14 15:37:05 hostname kernel: [961050.144100] 0000000000013e80 ffff88101a8993a0 ffff880e982693a0 0000000000000000 Dec 14 15:37:05 hostname kernel: [961050.144102] ffffffff81cdb2a0 ffffffff81cdb2a4 ffff880e982693a0 00000000ffffffff Dec 14 15:37:05 hostname kernel: [961050.144104] Call Trace: Dec 14 15:37:05 hostname kernel: [961050.144109] [<ffffffff817b2fa9>] schedule_preempt_disabled+0x29/0x70 Dec 14 15:37:05 hostname kernel: [961050.144111] [<ffffffff817b4c95>] __mutex_lock_slowpath+0x95/0x100 Dec 14 15:37:05 hostname kernel: [961050.144115] [<ffffffff811cfd66>] ? __kmalloc+0x226/0x280 Dec 14 15:37:05 hostname kernel: [961050.144117] [<ffffffff816a14a1>] ? net_alloc_generic+0x21/0x30 Dec 14 15:37:05 hostname kernel: [961050.144120] [<ffffffff817b4d23>] mutex_lock+0x23/0x37 Dec 14 15:37:05 hostname kernel: [961050.144122] [<ffffffff816a1c75>] copy_net_ns+0x75/0x150 Dec 14 15:37:05 hostname kernel: [961050.144125] [<ffffffff810943ad>] create_new_namespaces+0xfd/0x180 Dec 14 15:37:05 hostname kernel: [961050.144127] [<ffffffff810945ba>] unshare_nsproxy_namespaces+0x5a/0xc0 Dec 14 15:37:05 hostname kernel: [961050.144130] [<ffffffff8107439b>] SyS_unshare+0x15b/0x2e0 Dec 14 15:37:05 hostname kernel: [961050.144133] [<ffffffff817b6e4d>] system_call_fastpath+0x16/0x1b Dec 14 15:37:05 hostname kernel: [961050.144135] INFO: task ip:9896 blocked for more than 120 seconds. Dec 14 15:37:05 hostname kernel: [961050.151109] Tainted: G C 3.19.0-30-generic #34~14.04.1-Ubuntu Dec 14 15:37:05 hostname kernel: [961050.159558] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Dec 14 15:37:05 hostname kernel: [961050.168551] ip D ffff8804591cfde8 0 9896 9895 0x00000000 Dec 14 15:37:05 hostname kernel: [961050.168556] ffff8804591cfde8 ffff880814031d70 0000000000013e80 ffff8804591cffd8 Dec 14 15:37:05 hostname kernel: [961050.168558] 0000000000013e80 ffffffff81c1d4e0 ffff880814031d70 0000000000000000 Dec 14 15:37:05 hostname kernel: [961050.168560] ffffffff81cdb2a0 ffffffff81cdb2a4 ffff880814031d70 00000000ffffffff Dec 14 15:37:05 hostname kernel: [961050.168562] Call Trace: Dec 14 15:37:05 hostname kernel: [961050.168568] [<ffffffff817b2fa9>] schedule_preempt_disabled+0x29/0x70 Dec 14 15:37:05 hostname kernel: [961050.168571] [<ffffffff817b4c95>] __mutex_lock_slowpath+0x95/0x100 Dec 14 15:37:05 hostname kernel: [961050.168573] [<ffffffff817b4d23>] mutex_lock+0x23/0x37 Dec 14 15:37:05 hostname kernel: [961050.168577] [<ffffffff816a1c75>] copy_net_ns+0x75/0x150 Dec 14 15:37:05 hostname kernel: [961050.168581] [<ffffffff810943ad>] create_new_namespaces+0xfd/0x180 Dec 14 15:37:05 hostname kernel: [961050.168584] [<ffffffff810945ba>] unshare_nsproxy_namespaces+0x5a/0xc0 Dec 14 15:37:05 hostname kernel: [961050.168587] [<ffffffff8107439b>] SyS_unshare+0x15b/0x2e0 Dec 14 15:37:05 hostname kernel: [961050.168589] [<ffffffff817b6e4d>] system_call_fastpath+0x16/0x1b [1] http://www.spinics.net/lists/netdev/msg351337.html Cheers, James Dempsey -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1403152 Title: unregister_netdevice: waiting for lo to become free. Usage count To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1403152/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
