[PATCH 7/13 net-3.1-stable] sch_teql: fix lockdep splat
From: David Miller <davem@davemloft.net>
Date: 2011-12-06 21:33:31
Subsystem:
networking [general], tc subsystem, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds
From: Eric Dumazet <redacted> [ Upstream commit f7e57044eeb1841847c24aa06766c8290c202583 ] 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 <redacted> Signed-off-by: David S. Miller <davem@davemloft.net> --- net/sched/sch_teql.c | 31 ++++++++++++++++++++----------- 1 files changed, 20 insertions(+), 11 deletions(-)
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_qdisc_init(struct Qdisc *sch, struct nlattr *opt) 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 @@ __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device * } 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 @@ restart: 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);
--
1.7.7.3