ipv6: annotate data-races in rt6_probe()

Use READ_ONCE() while reading idev->cnf.rtr_probe_interval
while its value could be changed.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -645,14 +645,15 @@ static void rt6_probe(struct fib6_nh *fib6_nh)
 		write_lock_bh(&neigh->lock);
 		if (!(neigh->nud_state & NUD_VALID) &&
 		    time_after(jiffies,
-			       neigh->updated + idev->cnf.rtr_probe_interval)) {
+			       neigh->updated +
+			       READ_ONCE(idev->cnf.rtr_probe_interval))) {
 			work = kmalloc(sizeof(*work), GFP_ATOMIC);
 			if (work)
 				__neigh_set_probe_once(neigh);
 		}
 		write_unlock_bh(&neigh->lock);
 	} else if (time_after(jiffies, last_probe +
-				       idev->cnf.rtr_probe_interval)) {
+				       READ_ONCE(idev->cnf.rtr_probe_interval))) {
 		work = kmalloc(sizeof(*work), GFP_ATOMIC);
 	}