This is a note to let you know that I've just added the patch titled bonding: fix a potential double-unregister to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bonding-fix-a-potential-double-unregister.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Wed Aug 26 04:19:14 PM CEST 2020 From: Cong Wang <xiyou.wangcong@xxxxxxxxx> Date: Fri, 14 Aug 2020 20:05:58 -0700 Subject: bonding: fix a potential double-unregister From: Cong Wang <xiyou.wangcong@xxxxxxxxx> [ Upstream commit 832707021666411d04795c564a4adea5d6b94f17 ] When we tear down a network namespace, we unregister all the netdevices within it. So we may queue a slave device and a bonding device together in the same unregister queue. If the only slave device is non-ethernet, it would automatically unregister the bonding device as well. Thus, we may end up unregistering the bonding device twice. Workaround this special case by checking reg_state. Fixes: 9b5e383c11b0 ("net: Introduce unregister_netdevice_many()") Reported-by: syzbot+af23e7f3e0a7e10c8b67@xxxxxxxxxxxxxxxxxxxxxxxxx Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx> Cc: Andy Gospodarek <andy@xxxxxxxxxxxxx> Cc: Jay Vosburgh <j.vosburgh@xxxxxxxxx> Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/bonding/bond_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1940,7 +1940,8 @@ static int bond_release_and_destroy(str int ret; ret = bond_release(bond_dev, slave_dev); - if (ret == 0 && !bond_has_slaves(bond)) { + if (ret == 0 && !bond_has_slaves(bond) && + bond_dev->reg_state != NETREG_UNREGISTERING) { bond_dev->priv_flags |= IFF_DISABLE_NETPOLL; netdev_info(bond_dev, "Destroying bond %s\n", bond_dev->name); Patches currently in stable-queue which might be from xiyou.wangcong@xxxxxxxxx are queue-4.4/tipc-fix-uninit-skb-data-in-tipc_nl_compat_dumpit.patch queue-4.4/bonding-fix-a-potential-double-unregister.patch