Hi Dan, the CPU usage is zero, there is nothing popping up. The tasks causing the high load value are in D state. If I do "echo w > /proc/sysrq- trigger", I will get for every leaked NS:
[392149.562095] kworker/u81:40 D 0 4290 2 0x80000000 [392149.562112] Workqueue: netns cleanup_net [392149.562125] Call Trace: [392149.562135] __schedule+0x291/0x8a0 [392149.562146] schedule+0x2c/0x80 [392149.562157] schedule_timeout+0x182/0x360 [392149.562167] ? call_timer_fn+0x130/0x130 [392149.562177] msleep+0x2d/0x40 [392149.562188] ? msleep+0x2d/0x40 [392149.562199] netdev_run_todo+0x15e/0x5d0 [392149.562210] rtnl_unlock+0xe/0x10 [392149.562221] default_device_exit_batch+0x156/0x180 [392149.562233] ? do_wait_intr_irq+0x90/0x90 [392149.562245] cleanup_net+0x14e/0x2a0 [392149.562257] process_one_work+0x1ec/0x410 [392149.562270] worker_thread+0x32/0x410 [392149.562281] kthread+0x128/0x140 [392149.562292] ? process_one_work+0x410/0x410 [392149.562300] ? kthread_create_on_node+0x70/0x70 [392149.562305] ? do_syscall_64+0x67/0x130 [392149.562310] ? SyS_exit_group+0x14/0x20 [392149.562316] ret_from_fork+0x35/0x40 I am not sure how fine is to have e.g. thousands of such leaked namespaces - if I can't run out of some resources (kworker threads?). I am going to keep the machine running + generate even higher load there to see if I hit any such limit. Thanks JH -- 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: In Progress Status in linux source package in Trusty: In Progress Status in linux source package in Xenial: In Progress Status in linux source package in Zesty: Won't Fix Status in linux source package in Artful: In Progress Status in linux source package in Bionic: In Progress 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
