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
