Since xenial we have this very annoying behavior (unregister_netdevice: waiting for lo to become free. Usage count = 1) as well, which in turn makes a container reboot taking several minutes instead of seconds e.g. on vivid (lxc-ls -f also hangs for that time). E.g.:
[ +10.244888] unregister_netdevice: waiting for lo to become free. Usage count = 1 [Oct 2 17:16] INFO: task lxc-autostart:5321 blocked for more than 120 seconds. [ +0.007147] Tainted: P OE 4.4.0-96-generic #119-Ubuntu [ +0.006796] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ +0.007913] lxc-autostart D ffff883fb99fbcb8 0 5321 1 0x00000000 [ +0.000007] ffff883fb99fbcb8 ffffffffffffffff ffff883ff2a3aa00 ffff881fed2fe200 [ +0.000004] ffff883fb99fc000 ffffffff81ef79a4 ffff881fed2fe200 00000000ffffffff [ +0.000004] ffffffff81ef79a8 ffff883fb99fbcd0 ffffffff8183f165 ffffffff81ef79a0 [ +0.000004] Call Trace: [ +0.000014] [<ffffffff8183f165>] schedule+0x35/0x80 [ +0.000005] [<ffffffff8183f40e>] schedule_preempt_disabled+0xe/0x10 [ +0.000016] [<ffffffff81841049>] __mutex_lock_slowpath+0xb9/0x130 [ +0.000014] [<ffffffff818410df>] mutex_lock+0x1f/0x30 [ +0.000009] [<ffffffff8172da4e>] copy_net_ns+0x6e/0x120 [ +0.000009] [<ffffffff810a179b>] create_new_namespaces+0x11b/0x1d0 [ +0.000003] [<ffffffff810a18bd>] copy_namespaces+0x6d/0xa0 [ +0.000007] [<ffffffff8107f1d2>] copy_process+0x8e2/0x1b30 [ +0.000011] [<ffffffff810805b0>] _do_fork+0x80/0x360 [ +0.000015] [<ffffffff81003226>] ? exit_to_usermode_loop+0xa6/0xd0 [ +0.000004] [<ffffffff81080939>] SyS_clone+0x19/0x20 [ +0.000009] [<ffffffff81843272>] entry_SYSCALL_64_fastpath+0x16/0x71 [ +4.882232] unregister_netdevice: waiting for lo to become free. Usage count = 1 ... -- 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/1711407 Title: unregister_netdevice: waiting for lo to become free Status in linux package in Ubuntu: Confirmed Bug description: This is a "continuation" of bug 1403152, as that bug has been marked "fix released" and recent reports of failure may (or may not) be a new bug. Any further reports of the problem should please be reported here instead of that bug. -- [Impact] When shutting down and starting containers the container network namespace may experience a dst reference counting leak which results in this message repeated in the logs: unregister_netdevice: waiting for lo to become free. Usage count = 1 This can cause issues when trying to create net network namespace and thus block a user from creating new containers. [Test Case] See comment 16, reproducer provided at https://github.com/fho/docker- samba-loop To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1711407/+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
