netdev - [PATCH net] qdisc: fix a module refcount leak in qdisc_create

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Date:   Wed, 24 Aug 2016 09:39:02 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     netdev <netdev@...r.kernel.org>,
        John Fastabend <john.fastabend@...il.com>,
        stephen hemminger <stephen@...workplumber.org>,
        Jamal Hadi Salim <jhs@...atatu.com>
Subject: [PATCH net] qdisc: fix a module refcount leak in qdisc_create_dflt()

From: Eric Dumazet <edumazet@...gle.com>

Should qdisc_alloc() fail, we must release the module refcount
we got right before.

Fixes: 6da7c8fcbcbd ("qdisc: allow setting default queuing discipline")
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/sched/sch_generic.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index e95b67cd5718..657c13362b19 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -643,18 +643,19 @@ struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 	struct Qdisc *sch;
 
 	if (!try_module_get(ops->owner))
-		goto errout;
+		return NULL;
 
 	sch = qdisc_alloc(dev_queue, ops);
-	if (IS_ERR(sch))
-		goto errout;
+	if (IS_ERR(sch)) {
+		module_put(ops->owner);
+		return NULL;
+	}
 	sch->parent = parentid;
 
 	if (!ops->init || ops->init(sch, NULL) == 0)
 		return sch;
 
 	qdisc_destroy(sch);
-errout:
 	return NULL;
 }
 EXPORT_SYMBOL(qdisc_create_dflt);