Re: [net-next] bonding: don't allow the master to become its slave

Thu, Aug 09, 2012 at 09:03:23PM CEST, bhutchings@solarflare.com wrote:

On Thu, 2012-08-09 at 15:30 -0300, Flavio Leitner wrote:

quoted

It doesn't make any sense to allow the master to become
its slave. That creates a loop of events causing a crash.

What if there are other intermediate devices, e.g. the slave is a VLAN
sub-device of the bond?  And doesn't team also have this problem?

Yes, it does.

I think a more general check for such loops might be required.

I agree.

Ben.

quoted

Reported-by: Leonardo Chiquitto <redacted>
Signed-off-by: Flavio Leitner <redacted>
---
 drivers/net/bonding/bond_main.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 6fae5f3..5407b44 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c

@@ -1505,6 +1505,11 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 	int link_reporting;
 	int res = 0;
 
+	if (bond_dev == slave_dev) {
+		pr_err("%s: Error: cannot enslave itself.\n", bond_dev->name);
+		return -EINVAL;
+	}
+
 	if (!bond->params.use_carrier && slave_dev->ethtool_ops == NULL &&
 		slave_ops->ndo_do_ioctl == NULL) {
 		pr_warning("%s: Warning: no link monitoring support for %s\n",

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.