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Date: Fri, 08 Oct 2010 09:06:02 -0700 From: ebiederm@...ssion.com (Eric W. Biederman) To: Hans Schillstrom <hans.schillstrom@...csson.com> Cc: "netdev\@vger.kernel.org" <netdev@...r.kernel.org>, Daniel Lezcano <daniel.lezcano@...e.fr> Subject: Re: BUG ? ipip unregister_netdevice_many() Hans Schillstrom <hans.schillstrom@...csson.com> writes: > Hello > I'm trying to exit a network name space and it doesn't work (or am I doing something wrong?) > The only netdevices left are lo and the tunnels ip6tnl0, sit0 and tunl0 when exiting netns. > > A netns is created by lxc-execute with two interfaces eth0 eth1 (macvlan) > (see conf file at the end) > > Kernel: net-next-2.6 top from 4 october 2010 > > I added some printk's inn ipip.c ipip_exit_net() > ... > rtnl_lock(); > printk(KERN_ERR "ipip_exit_net(enter)\n"); > ipip_destroy_tunnels(ipn, &list); > printk(KERN_ERR "ipip_exit_net(1)\n"); > unregister_netdevice_queue(ipn->fb_tunnel_dev, &list); > printk(KERN_ERR "ipip_exit_net(2)\n"); > unregister_netdevice_many(&list); > printk(KERN_ERR "ipip_exit_net(3)\n"); > rtnl_unlock(); > printk(KERN_ERR "ipip_exit_net(exit)\n"); > > > Exit steps: > ===== Screen dump ===== > > # ifconfig eth0 0.0.0.0 down > # ifconfig eth1 0.0.0.0 down > # ifconfig lo 0.0.0.0 down > # ip li de eth0 > # ip li de eth1 > # ifconfig -a > ip6tnl0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 > NOARP MTU:1460 Metric:1 > RX packets:0 errors:0 dropped:0 overruns:0 frame:0 > TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) > > lo Link encap:Local Loopback > inet addr:127.0.0.1 Mask:255.0.0.0 > LOOPBACK MTU:16436 Metric:1 > RX packets:0 errors:0 dropped:0 overruns:0 frame:0 > TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) > > sit0 Link encap:IPv6-in-IPv4 > NOARP MTU:1480 Metric:1 > RX packets:0 errors:0 dropped:0 overruns:0 frame:0 > TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) > > tunl0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 > NOARP MTU:1480 Metric:1 > RX packets:0 errors:0 dropped:0 overruns:0 frame:0 > TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) > > # ps > PID USER VSZ STAT COMMAND > 1 root 12412 S /usr/lib64/lxc/lxc-init -- /var/bin/init > 2 root 4540 S /bin/ash /var/bin/init > 7 root 6640 S inetd > 8 root 4544 S /bin/ash > 26 root 4544 R ps > # lsmod > Module Size Used by Not tainted > macvlan 8709 0 > pcnet32 29549 0 > tg3 112093 0 > libphy 21043 1 tg3 > # kill 7 2 > # ps > PID USER VSZ STAT COMMAND > 1 root 12412 S /usr/lib64/lxc/lxc-init -- /var/bin/init > 8 root 4544 S /bin/ash > 28 root 4544 R ps > # exit ( here is the exit from netns ) > # ipip_exit_net(enter) > ipip_exit_net(1) > ipip_exit_net(2) > ------------[ cut here ]------------ > WARNING: at /home/hans/evip/kvm/net-next-2.6/kernel/sysctl.c:1953 > unregister_sysctl_table+0xc7/0xf9() This warning is caused by removing the parent directory before the child in the sysctl tables. Not strictly fatal but it is a problem. It may be worth looking at which sysctl tables ipip registers to see if we can rectify this. > Hardware name: Bochs > Modules linked in: macvlan pcnet32 tg3 libphy > Pid: 5, comm: kworker/u:0 Not tainted 2.6.36-rc3+ #7 > Call Trace: > [<ffffffff8103e281>] warn_slowpath_common+0x85/0x9d > [<ffffffff8103e2b3>] warn_slowpath_null+0x1a/0x1c > [<ffffffff81045e64>] unregister_sysctl_table+0xc7/0xf9 > [<ffffffff812c86a5>] neigh_sysctl_unregister+0x27/0x3f > [<ffffffff81342108>] addrconf_ifdown+0x415/0x45e > [<ffffffff81342b98>] addrconf_notify+0x756/0x7fe > [<ffffffff812cacfb>] ? neigh_ifdown+0xc3/0xd4 > [<ffffffff813622b3>] ? ip6mr_device_event+0x8d/0x9e > [<ffffffff8105eddb>] notifier_call_chain+0x37/0x63 > [<ffffffff8105ee8b>] raw_notifier_call_chain+0x14/0x16 > [<ffffffff812c15c7>] call_netdevice_notifiers+0x4a/0x4f > [<ffffffff812c1c1b>] rollback_registered_many+0x121/0x208 > [<ffffffff812c1d1d>] unregister_netdevice_many+0x1b/0x71 > [<ffffffff81324209>] ipip_exit_net+0xea/0x11a > [<ffffffff812bc941>] ? cleanup_net+0x0/0x198 > [<ffffffff812bc2cf>] ops_exit_list+0x2a/0x5b > [<ffffffff812bca39>] cleanup_net+0xf8/0x198 > [<ffffffff810568c7>] process_one_work+0x2a2/0x44d > [<ffffffff81056e35>] worker_thread+0x1db/0x34e > [<ffffffff81056c5a>] ? worker_thread+0x0/0x34e > [<ffffffff8105a030>] kthread+0x82/0x8a > [<ffffffff81003954>] kernel_thread_helper+0x4/0x10 > [<ffffffff81059fae>] ? kthread+0x0/0x8a > [<ffffffff81003950>] ? kernel_thread_helper+0x0/0x10 > ---[ end trace 939b5185219f32e7 ]--- > ipip_exit_net(3) > ipip_exit_net(exit) > unregister_netdevice: waiting for lo to become free. Usage count = 4 > unregister_netdevice: waiting for lo to become free. Usage count = 4 > unregister_netdevice: waiting for lo to become free. Usage count = 4 Nasty. Someone has left a reference lying around to one of the network devices. It is a reference that we can transfer to the loopback device at device exit time, but we never drop the reference and so the loopback interface never frees up. Ouch! There is the painful method of instrumenting of dev_hold and dev_release that may give you a clue. It may also be worth seeing which kinds of device reference we transfer from the loopback device when a device exits. Eric -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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