diff options
| author | Taehee Yoo <ap420073@gmail.com> | 2019-10-21 18:47:55 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-12 19:18:39 +0100 |
| commit | 1861904a6092ed411203c6a02c75bfc45b27cc3c (patch) | |
| tree | 1fe3ee5d59e5f25501001338df74de5fe2203c26 /drivers/net/macsec.c | |
| parent | addfc90b11df2c7fa4a8aa94ff2c113fda76710f (diff) | |
macsec: fix refcnt leak in module exit routine
[ 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>
Diffstat (limited to 'drivers/net/macsec.c')
| -rw-r--r-- | drivers/net/macsec.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c index aa204c98af79..9bcb7c3e879f 100644 --- a/drivers/net/macsec.c +++ b/drivers/net/macsec.c @@ -2993,12 +2993,10 @@ 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) @@ -3239,8 +3237,6 @@ 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, |