sch_tbf: Fix potential memory leak in tbf_change().

The allocated child qdisc is not freed in error conditions.
Defer the allocation after user configuration turns out to be
valid and acceptable.

Fixes: cc106e441a63b ("net: sched: tbf: fix the calculation of max_size")
Signed-off-by: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 1cb413f..4f505a0 100644 (file)
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -334,18 +334,6 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt)
                        qdisc_put_rtab(qdisc_get_rtab(&qopt->peakrate,
                                                      tb[TCA_TBF_PTAB]));
 
-       if (q->qdisc != &noop_qdisc) {
-               err = fifo_set_limit(q->qdisc, qopt->limit);
-               if (err)
-                       goto done;
-       } else if (qopt->limit > 0) {
-               child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit);
-               if (IS_ERR(child)) {
-                       err = PTR_ERR(child);
-                       goto done;
-               }
-       }
-
        buffer = min_t(u64, PSCHED_TICKS2NS(qopt->buffer), ~0U);
        mtu = min_t(u64, PSCHED_TICKS2NS(qopt->mtu), ~0U);
 
@@ -390,6 +378,18 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt)
                goto done;
        }
 
+       if (q->qdisc != &noop_qdisc) {
+               err = fifo_set_limit(q->qdisc, qopt->limit);
+               if (err)
+                       goto done;
+       } else if (qopt->limit > 0) {
+               child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit);
+               if (IS_ERR(child)) {
+                       err = PTR_ERR(child);
+                       goto done;
+               }
+       }
+
        sch_tree_lock(sch);
        if (child) {
                qdisc_tree_decrease_qlen(q->qdisc, q->qdisc->q.qlen);