Subject: [PATCH 02/22] bonding: fix a potential double-unregister

From: Cong Wang <[email-masked]>
Date: Fri, 14 Aug 2020 20:05:58 -0700

[ 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: [email-masked]
Cc: Eric Dumazet <[email-masked]>
Cc: Andy Gospodarek <[email-masked]>
Cc: Jay Vosburgh <[email-masked]>
Signed-off-by: Cong Wang <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 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 dba3dfa2658f..7949bbb0eaa7 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2084,7 +2084,8 @@ 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\n");
 		bond_remove_proc_entry(bond);
-- 
2.26.2