diff options
| author |   Maciej Fijalkowski <maciej.fijalkowski@intel.com> | 2026-08-28 18:49:18 +0200 |
|---|---|---|
| committer |   Jakub Kicinski <kuba@kernel.org> | 2026-08-30 14:30:59 -0700 |
| commit | a8455260b2e9c024d1872ac1c094793d55a7e537 (patch) | |
| tree | c34c2ac7a8036fe85cbeeb3ecaa97d699ad888d1 | |
| parent | vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del() (diff) | |
ipvlan: unregister upper devices outside pnodes_lockdavem/net
syzbot reported the following circular locking dependency:
xs->mutex -> netdev lock -> pnodes_lock -> net->xdp.lock -> xs->mutex
The pnodes_lock -> net->xdp.lock edge is recorded when
ipvlan_device_event(NETDEV_UNREGISTER) calls unregister_netdevice_many()
while holding pnodes_lock. A nested NETDEV_UNREGISTER notification for
an IPvlan device enters xsk_notifier(), which acquires net->xdp.lock.
Keep pnodes_lock only while marking the upper devices as dying, removing
them from port->ipvlans, and queueing them for unregistration. Once the
devices have been detached from the protected list, release pnodes_lock
before unregister_netdevice_many() invokes notifier callbacks.
The port remains alive across unregistration because
ipvlan_device_event() holds the reference acquired by ipvlan_port_get().
The dying flag prevents a concurrent ->dellink() callback from deleting a
queued device again.
Fixes: 35add1093e2f ("ipvlan: Protect ipvl_port.ipvlans with mutex.")
Reported-by: syzbot+aa48b5fe7bfda62d1682@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=aa48b5fe7bfda62d1682
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260828164918.451364-1-maciej.fijalkowski@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/ipvlan/ipvlan_main.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c index 4939cf67b336..f29864db662a 100644 --- a/drivers/net/ipvlan/ipvlan_main.c +++ b/drivers/net/ipvlan/ipvlan_main.c @@ -848,7 +848,6 @@ static int ipvlan_device_event(struct notifier_block *unused, __ipvlan_link_delete(net, ipvlan->dev, &lst_kill); } - unregister_netdevice_many(&lst_kill); break; } case NETDEV_FEAT_CHANGE: @@ -899,6 +898,9 @@ static int ipvlan_device_event(struct notifier_block *unused, mutex_unlock(&port->pnodes_lock); + /* Avoid invoking nested netdevice notifiers under pnodes_lock. */ + unregister_netdevice_many(&lst_kill); + ipvlan_port_put(port); return ret; |