Jiri, I just added a new artful version to the ppa, version 4.13.0-38.43+hf1711407v20180413b1; it's building right now. It should avoid the hang just like the last version from yesterday; but the last one blocked freeing any future net namespaces after one hangs; this one fixes that so even after a net namespace hangs, future ones will correctly clean up and get freed.
I also added debug to this new build that will show each net namespace alloc and free, like: [ 207.625857] net_namespace: alloced net ffff8d2eb3cae000 ... [ 208.152882] net_namespace: freeing net ffff8d2eb3cae000 and it has the same dbg during reproduction of this bug, where it hangs, like: [ 1363.377355] unregister_netdevice: possible namespace leak (netns ffff96ddf1c10000), have been waiting for 131032 seconds [ 1363.377393] (netns ffff96ddf1c10000): open sk ffff96ddf1e77380 family 2 state 4 dst_cache (null) rx_dst ffff96ddf532d800 creator generic_ip_connect+0x257/0x4f0 [cifs] [ 1363.377406] (netns ffff96ddf1c10000): dst ffff96ddf532d800 expires 0 error 0 obsolete 2 flags 0 refcnt 1 ops ipv4_dst_ops+0x0/0xc0 creator ip_route_input_rcu+0x6b3/0xd80 If you're able to test with today's build, let me know if you are able to reproduce the problem (see the 'namespace leak' message) and if it has worked around the container hang correctly. Thanks! -- 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 : firstname.lastname@example.org Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp