openvswitch: Fix refcount leak on force commit.

The reference count held for skb needs to be released when the skb's
nfct pointer is cleared regardless of if nf_ct_delete() is called or
not.

Failing to release the skb's reference cound led to deferred conntrack
cleanup spinning forever within nf_conntrack_cleanup_net_list() when
cleaning up a network namespace:

   kworker/u16:0-19025 [004] 45981067.173642: sched_switch: kworker/u16:0:19025 [120] R ==> rcu_preempt:7 [120]
   kworker/u16:0-19025 [004] 45981067.173651: kernel_stack: <stack trace>
=> ___preempt_schedule (ffffffffa001ed36)
=> _raw_spin_unlock_bh (ffffffffa0713290)
=> nf_ct_iterate_cleanup (ffffffffc00a4454)
=> nf_conntrack_cleanup_net_list (ffffffffc00a5e1e)
=> nf_conntrack_pernet_exit (ffffffffc00a63dd)
=> ops_exit_list.isra.1 (ffffffffa06075f3)
=> cleanup_net (ffffffffa0607df0)
=> process_one_work (ffffffffa0084c31)
=> worker_thread (ffffffffa008592b)
=> kthread (ffffffffa008bee2)
=> ret_from_fork (ffffffffa071b67c)

Fixes: dd41d33f0b03 ("openvswitch: Add force commit.")
Reported-by: Yang Song <yangsong@vmware.com>
Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Acked-by: Joe Stringer <joe@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index e0a8777..7b2c2fc 100644 (file)
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -643,8 +643,8 @@ static bool skb_nfct_cached(struct net *net,
                 */
                if (nf_ct_is_confirmed(ct))
                        nf_ct_delete(ct, 0, 0);
-               else
-                       nf_conntrack_put(&ct->ct_general);
+
+               nf_conntrack_put(&ct->ct_general);
                nf_ct_set(skb, NULL, 0);
                return false;
        }