(Updating the patch for the case when a non-loopback dev could be unregistered)
Currently during namespace cleanup, if ‘dst’ subsystem is holding a reference to the interface in the namespace, it does not get released. Current code first does a ’dev_hold’ on the same device followed by a ‘dev_put’ on the same device resulting in a no-op. This change fixes this leak by assigning the initial namespace’s loopback device to the ‘dst’ before releasing the reference to the network device being released. Additional reference: https://github.com/docker/docker/issues/5618 Signed-off-by: Jojy G Varghese <jojy.vargh...@gmail.com> --- net/core/dst.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/core/dst.c b/net/core/dst.c index a1656e3..7e45593 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -433,7 +433,11 @@ static void dst_ifdown(struct dst_entry *dst, struct net_device *dev, dst->input = dst_discard; dst->output = dst_discard_out; } else { - dst->dev = dev_net(dst->dev)->loopback_dev; + if (dst->dev == dev_net(dst->dev)->loopback_dev) + dst->dev = init_net.loopback_dev; + else + dst->dev = dev_net(dst->dev)->loopback_dev; + dev_hold(dst->dev); dev_put(dev); } -- 1.8.3.1 On Wed, Sep 7, 2016 at 6:55 PM, Jojy Varghese <jojy.vargh...@gmail.com> wrote: > During namespace cleanup, if ‘dst’ subsystem is holding > a reference to the loopback interface in the namespace, it does not get > released. This is because in the case where the net_device held by 'dst' > is same as the namespace's loopback net_device, current code first > does a ’dev_hold’ on the same device followed by a ‘dev_put’ on the > same device resulting in a no-op. > > This change fixes this leak by assigning the initial namespace’s loopback > device to the ‘dst’’ before releasing the reference to the network device > being unregistered. > > Additional reference: https://github.com/docker/docker/issues/5618 > > Signed-off-by: Jojy G Varghese <jojy.vargh...@gmail.com> > --- > net/core/dst.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/core/dst.c b/net/core/dst.c > index a1656e3..a18e8ea 100644 > --- a/net/core/dst.c > +++ b/net/core/dst.c > @@ -433,7 +433,7 @@ static void dst_ifdown(struct dst_entry *dst, > struct net_device *dev, > dst->input = dst_discard; > dst->output = dst_discard_out; > } else { > - dst->dev = dev_net(dst->dev)->loopback_dev; > + dst->dev = init_net.loopback_dev; > dev_hold(dst->dev); > dev_put(dev); > } > -- > 1.8.3.1 -- Jojy G Varghese
