Linux Ethernet Bridging - Jul 2010 - [Bridge] [BUG] bridge leaks 3 references on lo per up&down

On Wed, Jul 28, 2010 at 09:44:28AM +0200, David Lamparter
wrote:
> On Tue, Jul 27, 2010 at 10:02:49AM -0700, Stephen Hemminger wrote:
> > David Lamparter <equinox at diac24.net> wrote:
> > > unregister_netdevice: waiting for lo to become free. Usage count
= 4
> > > 
> > > unshare -n -- /bin/bash -c 'ip link add link lo veth0 type
veth peer
> > > name veth3 netns 1; brctl addbr br0; ip l s br0 up; ip a l; sleep
8'
When I do

unshare -n -- /bin/bash -c 'ip link add link lo veth0 type veth peer
	name veth3 netns 1; brctl addbr br0; \
	ip l s br0 up; sleep 8; ip l s br0 down; sleep 1;
	ip l s br0 up; sleep 8;'

I get "usage count = 7" on lo; when I add another up & down, I get
"usage count = 10". 4 times makes it a merry 13 refs...


-David

On Wed, Jul 28, 2010 at 11:58:25AM +0200, David Lamparter
wrote:
> unshare -n -- /bin/bash -c 'ip link add link lo veth0 type veth peer
>       name veth3 netns 1; brctl addbr br0; \
>       ip l s br0 up; sleep 8; ip l s br0 down; sleep 1;
>       ip l s br0 up; sleep 8;'
>
> I get "usage count = 7" on lo; when I add another up & down,
I get
> "usage count = 10". 4 times makes it a merry 13 refs...
It only happens with BRIDGE_IGMP_SNOOPING. As we don't need that, our
"fix" is just to run with it disabled... works pretty fine.

Herbert, you implemented bridge multicast support, maybe you can figure
out where these references are taken?


-David