From 4d293fe1c69c157c15ac06918a805e5fef036682 Mon Sep 17 00:00:00 2001 From: Di Zhu Date: Wed, 23 Jun 2021 11:21:08 +0800 Subject: [PATCH] bonding: allow nesting of bonding device The commit 3c9ef511b9fa ("bonding: avoid adding slave device with IFF_MASTER flag") fix a crash when add slave device with IFF_MASTER, but it rejects the scenario of nested bonding device. As Eric Dumazet described: since there indeed is a usage scenario about nesting bonding, we should not break it. So we add a new judgment condition to allow nesting of bonding device. Fixes: 3c9ef511b9fa ("bonding: avoid adding slave device with IFF_MASTER flag") Suggested-by: Jay Vosburgh Signed-off-by: Di Zhu Signed-off-by: David S. Miller --- drivers/net/bonding/bond_main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 16840c9..03b1a93 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1601,7 +1601,9 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev, int link_reporting; int res = 0, i; - if (slave_dev->flags & IFF_MASTER) { + if (slave_dev->flags & IFF_MASTER && + !netif_is_bond_master(slave_dev)) { + NL_SET_ERR_MSG(extack, "Device with IFF_MASTER cannot be enslaved"); netdev_err(bond_dev, "Error: Device with IFF_MASTER cannot be enslaved\n"); return -EPERM; -- 2.7.4