lkml.org 
[lkml]   [2022]   [Aug]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH net] net/sched: fix netdevice reference leaks in attach_one_default_qdisc()
On Wed, 17 Aug 2022 18:46:46 +0800 Wang Hai wrote:
> 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.

Could you provide more details on the failure path? My preference would
be to try to clean up properly there, if possible.

> 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;
> }
>

\
 
 \ /
  Last update: 2022-08-18 19:59    [W:0.078 / U:0.756 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site