sch_teql: fix lockdep splat
We need rcu_read_lock() protection before using dst_get_neighbour(), and
we must cache its value (pass it to __teql_resolve())
teql_master_xmit() is called under rcu_read_lock_bh() protection, its
not enough.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index a3b7120..4f4c52c 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -225,11 +225,11 @@
static int
-__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
+__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res,
+ struct net_device *dev, struct netdev_queue *txq,
+ struct neighbour *mn)
{
- struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
- struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
- struct neighbour *mn = dst_get_neighbour(skb_dst(skb));
+ struct teql_sched_data *q = qdisc_priv(txq->qdisc);
struct neighbour *n = q->ncache;
if (mn->tbl == NULL)
@@ -262,17 +262,26 @@
}
static inline int teql_resolve(struct sk_buff *skb,
- struct sk_buff *skb_res, struct net_device *dev)
+ struct sk_buff *skb_res,
+ struct net_device *dev,
+ struct netdev_queue *txq)
{
- struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
+ struct dst_entry *dst = skb_dst(skb);
+ struct neighbour *mn;
+ int res;
+
if (txq->qdisc == &noop_qdisc)
return -ENODEV;
- if (dev->header_ops == NULL ||
- skb_dst(skb) == NULL ||
- dst_get_neighbour(skb_dst(skb)) == NULL)
+ if (!dev->header_ops || !dst)
return 0;
- return __teql_resolve(skb, skb_res, dev);
+
+ rcu_read_lock();
+ mn = dst_get_neighbour(dst);
+ res = mn ? __teql_resolve(skb, skb_res, dev, txq, mn) : 0;
+ rcu_read_unlock();
+
+ return res;
}
static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -307,7 +316,7 @@
continue;
}
- switch (teql_resolve(skb, skb_res, slave)) {
+ switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
case 0:
if (__netif_tx_trylock(slave_txq)) {
unsigned int length = qdisc_pkt_len(skb);