Re: rcu locking issue in mpls output code?

[David Ahern]

On 6/19/16 6:45 PM, Lennert Buytenhek wrote:

diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index fb31aa8..802956b 100644
--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -105,12 +105,15 @@ static int mpls_output(struct net *net, struct sock *sk, 
struct sk_buff *skb)
                bos = false;
        }

+       rcu_read_lock_bh();
        if (rt)
                err = neigh_xmit(NEIGH_ARP_TABLE, out_dev, &rt->rt_gateway,
                                 skb);
        else if (rt6)
                err = neigh_xmit(NEIGH_ND_TABLE, out_dev, &rt6->rt6i_gateway,
                                 skb);
+       rcu_read_unlock_bh();
+
        if (err)
                net_dbg_ratelimited("%s: packet transmission failed: %d\n",
                                    __func__, err);

I think those need to be added to neigh_xmit in the

        if (likely(index < NEIGH_NR_TABLES)) {

        }

block.