datapath: Fix net exit.

Open vSwitch allows moving internal vport to different namespace
while still connected to the bridge. But when namespace deleted
OVS does not detach these vports, that results in dangling
pointer to netdevice which causes kernel panic as follows.
This issue is fixed by detaching all ovs ports from the deleted
namespace at net-exit.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
IP: [<ffffffffa0aadaa5>] ovs_vport_locate+0x35/0x80 [openvswitch]
Oops: 0000 [#1] SMP
Call Trace:
 [<ffffffffa0aa6391>] lookup_vport+0x21/0xd0 [openvswitch]
 [<ffffffffa0aa65f9>] ovs_vport_cmd_get+0x59/0xf0 [openvswitch]
 [<ffffffff8167e07c>] genl_family_rcv_msg+0x1bc/0x3e0
 [<ffffffff8167e319>] genl_rcv_msg+0x79/0xc0
 [<ffffffff8167d919>] netlink_rcv_skb+0xb9/0xe0
 [<ffffffff8167deac>] genl_rcv+0x2c/0x40
 [<ffffffff8167cffd>] netlink_unicast+0x12d/0x1c0
 [<ffffffff8167d3da>] netlink_sendmsg+0x34a/0x6b0
 [<ffffffff8162e140>] sock_sendmsg+0xa0/0xe0
 [<ffffffff8162e5e8>] ___sys_sendmsg+0x408/0x420
 [<ffffffff8162f541>] __sys_sendmsg+0x51/0x90
 [<ffffffff8162f592>] SyS_sendmsg+0x12/0x20
 [<ffffffff81764ee9>] system_call_fastpath+0x12/0x17

Reported-by: Assaf Muller <amuller@redhat.com>
Fixes: 46df7b81454("openvswitch: Add support for network namespaces.")
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Reviewed-by: Thomas Graf <tgraf@noironetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Upstream: 7b4577a9da ("openvswitch: Fix net exit").
Acked-by: Andy Zhou <azhou@nicira.com>

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 7b48a33..15e8c23 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -2080,14 +2080,55 @@ static int __net_init ovs_init_net(struct net *net)
        return 0;
 }
 
-static void __net_exit ovs_exit_net(struct net *net)
+static void __net_exit list_vports_from_net(struct net *net, struct net *dnet,
+                                           struct list_head *head)
 {
-       struct datapath *dp, *dp_next;
        struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
+       struct datapath *dp;
+
+       list_for_each_entry(dp, &ovs_net->dps, list_node) {
+               int i;
+
+               for (i = 0; i < DP_VPORT_HASH_BUCKETS; i++) {
+                       struct vport *vport;
+
+                       hlist_for_each_entry(vport, &dp->ports[i], dp_hash_node) {
+                               struct netdev_vport *netdev_vport;
+
+                               if (vport->ops->type != OVS_VPORT_TYPE_INTERNAL)
+                                       continue;
+
+                               netdev_vport = netdev_vport_priv(vport);
+                               if (dev_net(netdev_vport->dev) == dnet)
+                                       list_add(&vport->detach_list, head);
+                       }
+               }
+       }
+}
+
+static void __net_exit ovs_exit_net(struct net *dnet)
+{
+       struct datapath *dp, *dp_next;
+       struct ovs_net *ovs_net = net_generic(dnet, ovs_net_id);
+       struct vport *vport, *vport_next;
+       struct net *net;
+       LIST_HEAD(head);
 
        ovs_lock();
        list_for_each_entry_safe(dp, dp_next, &ovs_net->dps, list_node)
                __dp_destroy(dp);
+
+       rtnl_lock();
+       for_each_net(net)
+               list_vports_from_net(net, dnet, &head);
+       rtnl_unlock();
+
+       /* Detach all vports from given namespace. */
+       list_for_each_entry_safe(vport, vport_next, &head, detach_list) {
+               list_del(&vport->detach_list);
+               ovs_dp_detach_port(vport);
+       }
+
        ovs_unlock();
 
        cancel_work_sync(&ovs_net->dp_notify_work);

diff --git a/datapath/vport.h b/datapath/vport.h
index cfaea09..f6ce745 100644 (file)
--- a/datapath/vport.h
+++ b/datapath/vport.h
@@ -95,6 +95,7 @@ struct vport_portids {
  * @err_stats: Points to error statistics used and maintained by vport
  * @offset_stats: Added to actual statistics as a sop to compatibility with
  * XAPI for Citrix XenServer.  Deprecated.
+ * @detach_list: list used for detaching vport in net-exit call.
  */
 struct vport {
        struct rcu_head rcu;
@@ -111,6 +112,7 @@ struct vport {
        spinlock_t stats_lock;
        struct vport_err_stats err_stats;
        struct ovs_vport_stats offset_stats;
+       struct list_head detach_list;
 };
 
 /**