From: Wang Hai <wanghai38@huawei.com>
To: <jhs@mojatatu.com>, <xiyou.wangcong@gmail.com>,
<jiri@resnulli.us>, <davem@davemloft.net>, <edumazet@google.com>,
<kuba@kernel.org>, <pabeni@redhat.com>, <brouer@redhat.com>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH net] net/sched: fix netdevice reference leaks in attach_one_default_qdisc()
Date: Wed, 17 Aug 2022 18:46:46 +0800 [thread overview]
Message-ID: <20220817104646.22861-1-wanghai38@huawei.com> (raw)
In attach_default_qdiscs(), when attach default qdisc (fq_codel) fails
and fallback to noqueue, if the original attached qdisc is not released
and a new one is directly attached, this will cause netdevice reference
leaks.
The following is the bug log:
veth0: default qdisc (fq_codel) fail, fallback to noqueue
unregister_netdevice: waiting for veth0 to become free. Usage count = 32
leaked reference.
qdisc_alloc+0x12e/0x210
qdisc_create_dflt+0x62/0x140
attach_one_default_qdisc.constprop.41+0x44/0x70
dev_activate+0x128/0x290
__dev_open+0x12a/0x190
__dev_change_flags+0x1a2/0x1f0
dev_change_flags+0x23/0x60
do_setlink+0x332/0x1150
__rtnl_newlink+0x52f/0x8e0
rtnl_newlink+0x43/0x70
rtnetlink_rcv_msg+0x140/0x3b0
netlink_rcv_skb+0x50/0x100
netlink_unicast+0x1bb/0x290
netlink_sendmsg+0x37c/0x4e0
sock_sendmsg+0x5f/0x70
____sys_sendmsg+0x208/0x280
In attach_one_default_qdisc(), release the old one before attaching
a new qdisc to fix this bug.
Fixes: bf6dba76d278 ("net: sched: fallback to qdisc noqueue if default qdisc setup fail")
Signed-off-by: Wang Hai <wanghai38@huawei.com>
---
net/sched/sch_generic.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index d47b9689eba6..87b61ef14497 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -1140,6 +1140,11 @@ static void attach_one_default_qdisc(struct net_device *dev,
if (!netif_is_multiqueue(dev))
qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
+
+ if (dev_queue->qdisc_sleeping &&
+ dev_queue->qdisc_sleeping != &noop_qdisc)
+ qdisc_put(dev_queue->qdisc_sleeping);
+
dev_queue->qdisc_sleeping = qdisc;
}
--
2.17.1
next reply other threads:[~2022-08-17 10:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-17 10:46 Wang Hai [this message]
2022-08-18 17:56 ` [PATCH net] net/sched: fix netdevice reference leaks in attach_one_default_qdisc() Jakub Kicinski
2022-08-19 15:58 ` wanghai (M)
2022-08-25 12:29 ` wanghai (M)
2022-08-25 15:59 ` Jakub Kicinski
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