Hi,
On Wed, 4 Aug 2010 14:46:18 -0700
Greg KH <greg@kroah.com> wrote:
Just in case I provide the complete scenario again below.
If I can help somehow (provide further information, test something...)
of course I'll happily do so.
In an network namespace I can use an tun/tap tunnel through ssh and
when closing that namespace then eveything is fine.
But when using openvpn (also tunnel trough tun/tap) in an network
namespace and then closing that namespace I get:
unregister_netdevice: waiting for lo to become free
[repeated]
Please see the following two examples showing that difference:
# > unshare -n /bin/bash
# > # how to setup veth device pair to get connectivity into namespace not shown here
# > tunctl -u ml -t tap1
# > ssh -o Tunnel=Ethernet -w 1:1 somewhere
[ running some traffic over tap1 not shown here ]
^d # logging out from somewhere
# > tunctl -d tap1
# > exit # logging out from shell in network namespace
Now the veth device pair used automagically vanishes and nothing
from that different network namespace remains - very well.
but
# > unshare -n /bin/bash
# > # how to setup veth device pair to get connectivity into namespace not shown here
# > openvpn --config some.config
[ running some traffic over vpn device not shown here ]
^c # stopping openvpn
# > lsof -i
# > netstat -an
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address
State Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
# > ps ax|grep openvpn|grep -v grep
# > # cannot find anything that suggests there is anything left from that openvpn session
# > exit # logging out from shell in network namespace
Now I get
Jul 10 20:02:36 doris kernel: unregister_netdevice: waiting for lo to
become free. Usage count = 3 [repeated]
Now one might say it is fault of openvpn (used OpenVPN 2.1_rc20
i586-suse-linux - the one in openSuSE 11.2 package - EDIT: meanwhile it
is 2.1.1, openSuSE 11.3 ), openvpn didn't close some ressource and ssh
does fine.
But: should'nt kernel clean up after process when it exits?
And/or: Should'nt kernel clean up if last process in network namespace
exits - there is nothing left which might use that interface?!
--
MfG,
Michael Leun
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