CVE-2022-49958
net/sched: fix netdevice reference leaks in attach_default_qdiscs()
We use these services and cookies to improve your user experience. You may opt out if you wish, however, this may limit some features on this site.
Please see our statement on Data Privacy.
net/sched: fix netdevice reference leaks in attach_default_qdiscs()
In the Linux kernel, the following vulnerability has been resolved: net/sched: fix netdevice reference leaks in attach_default_qdiscs() In attach_default_qdiscs(), if a dev has multiple queues and queue 0 fails to attach qdisc because there is no memory in attach_one_default_qdisc(). Then dev->qdisc will be noop_qdisc by default. But the other queues may be able to successfully attach to default qdisc. In this case, the fallback to noqueue process will be triggered. 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 Fix this bug by clearing any non-noop qdiscs that may have been assigned before trying to re-attach.
Reserved 2025-06-18 | Published 2025-06-18 | Updated 2025-06-18 | Assigner Linuxgit.kernel.org/...c/44dfa645895a56f65461249deb5b81cd16560e2a
git.kernel.org/...c/a420d587260185407eda9c5766cfa9bdd5c39a56
git.kernel.org/...c/0c6c522857151ac00150fd01baeebf231fb7d142
git.kernel.org/...c/f612466ebecb12a00d9152344ddda6f6345f04dc
Support options
