[PKT_SCHED]: Fix OOPS when removing devices from a teql queuing discipline

tecl_reset() is called from deactivate and qdisc is set to noop already,
but subsequent teql_xmit does not know about it and dereference private
data as teql qdisc and thus oopses.
not catch it first :)

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index 421281d9dd1d..c0ed06d4a504 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -252,6 +252,9 @@ __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)
 {
+        if (dev->qdisc == &noop_qdisc)
+                return -ENODEV;
+
         if (dev->header_ops == NULL ||
             skb->dst == NULL ||
             skb->dst->neighbour == NULL)