pkt_sched: Fix sch_sfq vs tc_modify_qdisc oops

sch_sfq as a classful qdisc needs the .leaf handler. Otherwise, there
is an oops possible in tc_modify_qdisc()/check_loop().

Fixes commit 7d2681a6ff4f9ab5e48d02550b4c6338f1638998

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index b8bcb2096df8..201cbac2b32c 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -508,6 +508,11 @@ nla_put_failure:
         return -1;
 }
 
+static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg)
+{
+        return NULL;
+}
+
 static unsigned long sfq_get(struct Qdisc *sch, u32 classid)
 {
         return 0;
@@ -575,6 +580,7 @@ static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 }
 
 static const struct Qdisc_class_ops sfq_class_ops = {
+        .leaf           =       sfq_leaf,
         .get            =       sfq_get,
         .put            =       sfq_put,
         .tcf_chain      =       sfq_find_tcf,