net: sched: ensure n arg not empty before call bind_class

All bind_class callbacks are directly returned when n arg is empty.
Therefore, bind_class is invoked only when n arg is not empty.

Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 7c15f1f3da1770e74aa80eaf89a06a3122d5db59..c98af0ada706efee202a20a6bfb6f2b984106f45 100644 (file)
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1915,7 +1915,7 @@ static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
 {
        struct tcf_bind_args *a = (void *)arg;
 
-       if (tp->ops->bind_class) {
+       if (n && tp->ops->bind_class) {
                struct Qdisc *q = tcf_block_q(tp->chain->block);
 
                sch_tree_lock(q);