Just chiming in here, I contacted Rodrigo off-list and was verging towards that same patch. More below.
I suspect there's two issues here with very similar symptoms. In particular post #8 which mentions people reporting that 3.14 improves the situation. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1403152/comments/8 I've been chasing a bug in 3.13 with docker containers and connection tracking which is fixed in 3.14, by this patch: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e53376bef2cd97d3e3f61fdc677fb8da7d03d0da Note that the commit message for the above commit fixes a different issue, but I've been able to produce issues of the nature in this thread (hung docker / ip netns add commands like in post #6) before applying this patch, but cannot reproduce after. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1403152/comments/6 In the issue that I face, I can find a kworker thread using up an entire core, and when I cat /proc/$pid/stack I see this: <ffffffffbe01e9b6>] ___preempt_schedule+0x56/0xb0 [<ffffffffc02223e4>] nf_ct_iterate_cleanup+0x134/0x160 [nf_conntrack] [<ffffffffc0223dae>] nf_conntrack_cleanup_net_list+0x4e/0x170 [nf_conntrack] [<ffffffffc022436d>] nf_conntrack_pernet_exit+0x4d/0x60 [nf_conntrack] [<ffffffffbe6040d3>] ops_exit_list.isra.1+0x53/0x60 [<ffffffffbe6048d0>] cleanup_net+0x100/0x1d0 [<ffffffffbe084991>] process_one_work+0x171/0x470 [<ffffffffbe08563b>] worker_thread+0x11b/0x3a0 [<ffffffffbe08bb82>] kthread+0xd2/0xf0 [<ffffffffbe71757c>] ret_from_fork+0x7c/0xb0 [<ffffffffffffffff>] 0xffffffffffffffff The kworker is looping forever and failing to clean up conntrack state. All the while, it holds the global netns lock. Given that I've bisected to the commit linked above which is to do with refcounting, I suspect that borked refcounting on conntrack entries makes them impossible to properly free/destroy, which prevents this worker from cleaning up the namespace, which then goes on to prevent anything else from interacting with namespaces (add/delete/etc). -- 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/1403152 Title: unregister_netdevice: waiting for lo to become free. Usage count Status in The Linux Kernel: Unknown Status in linux package in Ubuntu: In Progress Status in linux source package in Trusty: Confirmed Status in linux source package in Utopic: Confirmed Bug description: I currently running trusty latest patches and i get on these hardware and software: Ubuntu 3.13.0-43.72-generic 3.13.11.11 processor : 7 vendor_id : GenuineIntel cpu family : 6 model : 77 model name : Intel(R) Atom(TM) CPU C2758 @ 2.40GHz stepping : 8 microcode : 0x11d cpu MHz : 2400.000 cache size : 1024 KB physical id : 0 siblings : 8 core id : 7 cpu cores : 8 apicid : 14 initial apicid : 14 fpu : yes fpu_exception : yes cpuid level : 11 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 movbe popcnt tsc_deadline_timer aes rdrand lahf_lm 3dnowprefetch arat epb dtherm tpr_shadow vnmi flexpriority ept vpid tsc_adjust smep erms bogomips : 4799.48 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: somehow reproducable the subjected error, and lxc is working still but not more managable until a reboot. managable means every command hangs. I saw there are alot of bugs but they seams to relate to older version and are closed, so i decided to file a new one? I run alot of machine with trusty an lxc containers but only these kind of machines produces these errors, all other don't show these odd behavior. thx in advance meno To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1403152/+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