1 files changed, 13 insertions, 2 deletions

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 5173c1e1b19c..17513252e83f 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -528,7 +528,7 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
         unsigned int size;
         int err = -ENOBUFS;
 
-        /* ensure that the Qdisc and the private data are 32-byte aligned */
+        /* ensure that the Qdisc and the private data are 64-byte aligned */
         size = QDISC_ALIGN(sizeof(*sch));
         size += ops->priv_size + (QDISC_ALIGNTO - 1);
 
@@ -590,6 +590,13 @@ void qdisc_reset(struct Qdisc *qdisc)
 }
 EXPORT_SYMBOL(qdisc_reset);
 
+static void qdisc_rcu_free(struct rcu_head *head)
+{
+        struct Qdisc *qdisc = container_of(head, struct Qdisc, rcu_head);
+
+        kfree((char *) qdisc - qdisc->padded);
+}
+
 void qdisc_destroy(struct Qdisc *qdisc)
 {
         const struct Qdisc_ops  *ops = qdisc->ops;
@@ -613,7 +620,11 @@ void qdisc_destroy(struct Qdisc *qdisc)
         dev_put(qdisc_dev(qdisc));
 
         kfree_skb(qdisc->gso_skb);
-        kfree((char *) qdisc - qdisc->padded);
+        /*
+         * gen_estimator est_timer() might access qdisc->q.lock,
+         * wait a RCU grace period before freeing qdisc.
+         */
+        call_rcu(&qdisc->rcu_head, qdisc_rcu_free);
 }
 EXPORT_SYMBOL(qdisc_destroy);