net_sched: use tcf_queue_work() in route filter

Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by: Chris Mi <[email protected]> Cc: Daniel Borkmann <[email protected]> Cc: Jiri Pirko <[email protected]> Cc: John Fastabend <[email protected]> Cc: Jamal Hadi Salim <[email protected]> Cc: "Paul E. McKenney" <[email protected]> Signed-off-by: Cong Wang <[email protected]> Signed-off-by: David S. Miller <[email protected]>
cail · Oct 29, 2017 · c2f3f31 · c2f3f31
1 parent c0d378e
commit c2f3f31
Showing 1 changed file with 16 additions and 3 deletions.
diff --git a/net/sched/cls_route.c b/net/sched/cls_route.c
@@ -57,7 +57,10 @@ struct route4_filter {
 	u32			handle;
 	struct route4_bucket	*bkt;
 	struct tcf_proto	*tp;
-	struct rcu_head		rcu;
+	union {
+		struct work_struct	work;
+		struct rcu_head		rcu;
+	};
 };
 
 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
@@ -254,12 +257,22 @@ static int route4_init(struct tcf_proto *tp)
 	return 0;
 }
 
-static void route4_delete_filter(struct rcu_head *head)
+static void route4_delete_filter_work(struct work_struct *work)
 {
-	struct route4_filter *f = container_of(head, struct route4_filter, rcu);
+	struct route4_filter *f = container_of(work, struct route4_filter, work);
 
+	rtnl_lock();
 	tcf_exts_destroy(&f->exts);
 	kfree(f);
+	rtnl_unlock();
+}
+
+static void route4_delete_filter(struct rcu_head *head)
+{
+	struct route4_filter *f = container_of(head, struct route4_filter, rcu);
+
+	INIT_WORK(&f->work, route4_delete_filter_work);
+	tcf_queue_work(&f->work);
 }
 
 static void route4_destroy(struct tcf_proto *tp)