From: Di Zhu <zhudi21@huawei.com> mainline-inclusion from mainline-v5.16-rc7 commit 4d293fe1c69c157c15ac06918a805e5fef036682 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4RADY CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ------------------------------------------------- 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 <jay.vosburgh@canonical.com> Signed-off-by: Di Zhu <zhudi21@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Aichun Li <liaichun@huawei.com> Signed-off-by: Aichun Li <liaichun@huawei.com> Reviewed-by: Yue Haibing <yuehaibing@huawei.com> Reviewed-by: wuchangye <wuchangye@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- 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 97b9187bc8af..cb823e2da910 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1700,7 +1700,9 @@ 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; -- 2.20.1