[NET]: Fix dev->qdisc race for NETDEV_TX_LOCKED case
When transmit fails with NETDEV_TX_LOCKED the skb is requeued
to dev->qdisc again. The dev->qdisc pointer is protected by
the queue lock which needs to be dropped when attempting to
transmit and acquired again before requeing. The problem is
that qdisc_restart() fetches the dev->qdisc pointer once and
stores it in the `q' variable which is invalidated when
dropping the queue_lock, therefore the variable needs to be
refreshed before requeueing.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 3385ee5..a8240c5 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -139,6 +139,7 @@
}
if (ret == NETDEV_TX_LOCKED && nolock) {
spin_lock(&dev->queue_lock);
+ q = dev->qdisc;
goto collision;
}
}