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sch_teql: fix lockdep splat

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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>
This commit is contained in:
Eric Dumazet 2011-11-30 04:08:58 +00:00 committed by David S. Miller
parent 15fc1f3617
commit f7e57044ee
1 changed files with 20 additions and 11 deletions
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31
net/sched/sch_teql.c
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@ -225,11 +225,11 @@ static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
static int 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(txq->qdisc);
struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
struct neighbour *mn = dst_get_neighbour(skb_dst(skb));
struct neighbour *n = q->ncache; struct neighbour *n = q->ncache;
if (mn->tbl == NULL) if (mn->tbl == NULL)
@ -262,17 +262,26 @@ __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *
} }
static inline int teql_resolve(struct sk_buff *skb, 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) if (txq->qdisc == &noop_qdisc)
return -ENODEV; return -ENODEV;
if (dev->header_ops == NULL || if (!dev->header_ops || !dst)
skb_dst(skb) == NULL ||
dst_get_neighbour(skb_dst(skb)) == NULL)
return 0; 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) static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
@ -307,7 +316,7 @@ restart:
continue; continue;
} }
switch (teql_resolve(skb, skb_res, slave)) { switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
case 0: case 0:
if (__netif_tx_trylock(slave_txq)) { if (__netif_tx_trylock(slave_txq)) {
unsigned int length = qdisc_pkt_len(skb); unsigned int length = qdisc_pkt_len(skb);