Messages in this thread Patch in this message | | | From | Wang Hai <> | Subject | [PATCH net] net/sched: fix netdevice reference leaks in attach_one_default_qdisc() | Date | Wed, 17 Aug 2022 18:46:46 +0800 |
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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
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