[Bridge] [PATCH v2] net/bridge: Use __in6_dev_get rather than in6_dev_get in br_validate_ipv6
Pablo Neira Ayuso
pablo at netfilter.org
Wed Jul 8 09:04:21 UTC 2015
On Tue, Jul 07, 2015 at 11:34:34AM -0700, Stephen Hemminger wrote:
> On Tue, 7 Jul 2015 15:55:21 +0100
> Julien Grall <julien.grall at citrix.com> wrote:
> > The commit efb6de9b4ba0092b2c55f6a52d16294a8a698edd "netfilter: bridge:
> > forward IPv6 fragmented packets" introduced a new function
> > br_validate_ipv6 which take a reference on the inet6 device. Although,
> > the reference is not released at the end.
> > This will result to the impossibility to destroy any netdevice using
> > ipv6 and bridge.
> > It's possible to directly retrieve the inet6 device without taking a
> > reference as all netfilter hooks are protected by rcu_read_lock via
> > nf_hook_slow.
> > Spotted while trying to destroy a Xen guest on the upstream Linux:
> > "unregister_netdevice: waiting for vif1.0 to become free. Usage count = 1"
> > Signed-off-by: Julien Grall <julien.grall at citrix.com>
> > Cc: Bernhard Thaler <bernhard.thaler at wvnet.at>
> > Cc: Pablo Neira Ayuso <pablo at netfilter.org>
> > Cc: fw at strlen.de
> > Cc: ian.campbell at citrix.com
> > Cc: wei.liu2 at citrix.com
> > Cc: Bob Liu <bob.liu at oracle.com>
> > ---
> > Note that it's impossible to create new guest after this message.
> > I'm not sure if it's normal.
> > Changes in v2:
> > - Don't take a reference to inet6.
> > - This was "net/bridge: Add missing in6_dev_put in
> > br_validate_ipv6" 
> >  https://lkml.org/lkml/2015/7/3/443
> > ---
> > net/bridge/br_netfilter_ipv6.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> I like this simple solution
> Acked-by: Stephen Hemminger <stephen at networkplumber.org>
More information about the Bridge