4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gao Feng <gfree.wind@xxxxxxxxxxx> [ Upstream commit d02fd6e7d2933ede6478a15f9e4ce8a93845824e ] Because the macvlan_uninit would free the macvlan port, so there is one double free case in macvlan_common_newlink. When the macvlan port is just created, then register_netdevice or netdev_upper_dev_link failed and they would invoke macvlan_uninit. Then it would reach the macvlan_port_destroy which triggers the double free. Signed-off-by: Gao Feng <gfree.wind@xxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/macvlan.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -1441,9 +1441,14 @@ int macvlan_common_newlink(struct net *s return 0; unregister_netdev: + /* macvlan_uninit would free the macvlan port */ unregister_netdevice(dev); + return err; destroy_macvlan_port: - if (create) + /* the macvlan port may be freed by macvlan_uninit when fail to register. + * so we destroy the macvlan port only when it's valid. + */ + if (create && macvlan_port_get_rtnl(dev)) macvlan_port_destroy(port->dev); return err; }