From: Taehee Yoo ap420073@gmail.com
[ Upstream commit 2bce1ebed17da54c65042ec2b962e3234bad5b47 ]
When a macsec interface is created, it increases a refcnt to a lower device(real device). when macsec interface is deleted, the refcnt is decreased in macsec_free_netdev(), which is ->priv_destructor() of macsec interface.
The problem scenario is this. When nested macsec interfaces are exiting, the exit routine of the macsec module makes refcnt leaks.
Test commands: ip link add dummy0 type dummy ip link add macsec0 link dummy0 type macsec ip link add macsec1 link macsec0 type macsec modprobe -rv macsec
[ 208.629433] unregister_netdevice: waiting for macsec0 to become free. Usage count = 1
Steps of exit routine of macsec module are below. 1. Calls ->dellink() in __rtnl_link_unregister(). 2. Checks refcnt and wait refcnt to be 0 if refcnt is not 0 in netdev_run_todo(). 3. Calls ->priv_destruvtor() in netdev_run_todo().
Step2 checks refcnt, but step3 decreases refcnt. So, step2 waits forever.
This patch makes the macsec module do not hold a refcnt of the lower device because it already holds a refcnt of the lower device with netdev_upper_dev_link().
Fixes: c09440f7dcb3 ("macsec: introduce IEEE 802.1AE driver") Signed-off-by: Taehee Yoo ap420073@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/macsec.c | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c index 0dc92d2faa64d..05115fb0c97a9 100644 --- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -3008,12 +3008,10 @@ static const struct nla_policy macsec_rtnl_policy[IFLA_MACSEC_MAX + 1] = { static void macsec_free_netdev(struct net_device *dev) { struct macsec_dev *macsec = macsec_priv(dev); - struct net_device *real_dev = macsec->real_dev;
free_percpu(macsec->stats); free_percpu(macsec->secy.tx_sc.stats);
- dev_put(real_dev); }
static void macsec_setup(struct net_device *dev) @@ -3268,8 +3266,6 @@ static int macsec_newlink(struct net *net, struct net_device *dev, if (err < 0) return err;
- dev_hold(real_dev); - macsec->nest_level = dev_get_nest_level(real_dev) + 1; netdev_lockdep_set_classes(dev); lockdep_set_class_and_subclass(&dev->addr_list_lock,