From: Xin Long lucien.xin@gmail.com
[ Upstream commit c492d4c74dd3f87559883ffa0f94a8f1ae3fe5f5 ]
This patch is to fix a dst defcnt leak, which can be reproduced by doing:
# ip net a c; ip net a s; modprobe tipc # ip net e s ip l a n eth1 type veth peer n eth1 netns c # ip net e c ip l s lo up; ip net e c ip l s eth1 up # ip net e s ip l s lo up; ip net e s ip l s eth1 up # ip net e c ip a a 1.1.1.2/8 dev eth1 # ip net e s ip a a 1.1.1.1/8 dev eth1 # ip net e c tipc b e m udp n u1 localip 1.1.1.2 # ip net e s tipc b e m udp n u1 localip 1.1.1.1 # ip net d c; ip net d s; rmmod tipc
and it will get stuck and keep logging the error:
unregister_netdevice: waiting for lo to become free. Usage count = 1
The cause is that a dst is held by the udp sock's sk_rx_dst set on udp rx path with udp_early_demux == 1, and this dst (eventually holding lo dev) can't be released as bearer's removal in tipc pernet .exit happens after lo dev's removal, default_device pernet .exit.
"There are two distinct types of pernet_operations recognized: subsys and device. At creation all subsys init functions are called before device init functions, and at destruction all device exit functions are called before subsys exit function."
So by calling register_pernet_device instead to register tipc_net_ops, the pernet .exit() will be invoked earlier than loopback dev's removal when a netns is being destroyed, as fou/gue does.
Note that vxlan and geneve udp tunnels don't have this issue, as the udp sock is released in their device ndo_stop().
This fix is also necessary for tipc dst_cache, which will hold dsts on tx path and I will introduce in my next patch.
Reported-by: Li Shuang shuali@redhat.com Signed-off-by: Xin Long lucien.xin@gmail.com Acked-by: Jon Maloy jon.maloy@ericsson.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/tipc/core.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
--- a/net/tipc/core.c +++ b/net/tipc/core.c @@ -129,7 +129,7 @@ static int __init tipc_init(void) if (err) goto out_sysctl;
- err = register_pernet_subsys(&tipc_net_ops); + err = register_pernet_device(&tipc_net_ops); if (err) goto out_pernet;
@@ -137,7 +137,7 @@ static int __init tipc_init(void) if (err) goto out_socket;
- err = register_pernet_subsys(&tipc_topsrv_net_ops); + err = register_pernet_device(&tipc_topsrv_net_ops); if (err) goto out_pernet_topsrv;
@@ -148,11 +148,11 @@ static int __init tipc_init(void) pr_info("Started in single node mode\n"); return 0; out_bearer: - unregister_pernet_subsys(&tipc_topsrv_net_ops); + unregister_pernet_device(&tipc_topsrv_net_ops); out_pernet_topsrv: tipc_socket_stop(); out_socket: - unregister_pernet_subsys(&tipc_net_ops); + unregister_pernet_device(&tipc_net_ops); out_pernet: tipc_unregister_sysctl(); out_sysctl: @@ -167,9 +167,9 @@ out_netlink: static void __exit tipc_exit(void) { tipc_bearer_cleanup(); - unregister_pernet_subsys(&tipc_topsrv_net_ops); + unregister_pernet_device(&tipc_topsrv_net_ops); tipc_socket_stop(); - unregister_pernet_subsys(&tipc_net_ops); + unregister_pernet_device(&tipc_net_ops); tipc_netlink_stop(); tipc_netlink_compat_stop(); tipc_unregister_sysctl();