From 17631ac8eb6e56fb732f9bdfaa374e1980c6e727 Mon Sep 17 00:00:00 2001
From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Fri, 14 Aug 2020 20:05:58 -0700
Subject: [PATCH 3/9] bonding: fix a potential double-unregister
Git-commit: 832707021666411d04795c564a4adea5d6b94f17
Patch-mainline: v5.9-rc2
References: git-fixes
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@syzkaller.appspotmail.com
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/bonding/bond_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 4534bed7d8ef..64af4c03b47e 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2029,7 +2029,8 @@ static int bond_release_and_destroy(struct net_device *bond_dev,
int ret;
ret = __bond_release_one(bond_dev, slave_dev, false, true);
- 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);
--
2.16.4