2 files changed, 26 insertions, 10 deletions

diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 92435a882f..9c15c4888d 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -2,9 +2,7 @@
 # Traffic control configuration.
 # 
 
-menu "QoS and/or fair queueing"
-
-config NET_SCHED
+menuconfig NET_SCHED
         bool "QoS and/or fair queueing"
         select NET_SCH_FIFO
         ---help---
@@ -41,9 +39,6 @@ config NET_SCHED
           The available schedulers are listed in the following questions; you
           can say Y to as many as you like. If unsure, say N now.
 
-config NET_SCH_FIFO
-        bool
-
 if NET_SCHED
 
 comment "Queueing/Scheduling"
@@ -500,4 +495,5 @@ config NET_CLS_IND
 
 endif # NET_SCHED
 
-endmenu
+config NET_SCH_FIFO
+        bool
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index e01d57692c..fa1a6f45dc 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -556,6 +556,7 @@ void dev_deactivate(struct net_device *dev)
 {
         struct Qdisc *qdisc;
         struct sk_buff *skb;
+        int running;
 
         spin_lock_bh(&dev->queue_lock);
         qdisc = dev->qdisc;
@@ -571,12 +572,31 @@ void dev_deactivate(struct net_device *dev)
 
         dev_watchdog_down(dev);
 
-        /* Wait for outstanding dev_queue_xmit calls. */
+        /* Wait for outstanding qdisc-less dev_queue_xmit calls. */
         synchronize_rcu();
 
         /* Wait for outstanding qdisc_run calls. */
-        while (test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state))
-                yield();
+        do {
+                while (test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state))
+                        yield();
+
+                /*
+                 * Double-check inside queue lock to ensure that all effects
+                 * of the queue run are visible when we return.
+                 */
+                spin_lock_bh(&dev->queue_lock);
+                running = test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state);
+                spin_unlock_bh(&dev->queue_lock);
+
+                /*
+                 * The running flag should never be set at this point because
+                 * we've already set dev->qdisc to noop_qdisc *inside* the same
+                 * pair of spin locks.  That is, if any qdisc_run starts after
+                 * our initial test it should see the noop_qdisc and then
+                 * clear the RUNNING bit before dropping the queue lock.  So
+                 * if it is set here then we've found a bug.
+                 */
+        } while (WARN_ON_ONCE(running));
 }
 
 void dev_init_scheduler(struct net_device *dev)