On Thu, Jul 6, 2017 at 5:08 AM, Nicolas Dichtel <[email protected]> wrote: > Le 06/07/2017 à 00:43, Cong Wang a écrit : >> On Wed, Jul 5, 2017 at 8:57 AM, Nicolas Dichtel >> <[email protected]> wrote: >>> When a device changes from one netns to another, it's first unregistered, >>> then the netns reference is updated and the dev is registered in the new >>> netns. Thus, when a slave moves to another netns, it is first >>> unregistered. This triggers a NETDEV_UNREGISTER event which is caught by >>> the bonding driver. The driver calls bond_release(), which calls >>> dev_set_mtu() and thus triggers NETDEV_CHANGEMTU (the device is still in >>> the old netns). >> >> I think in this special case it is meaningless to send >> NETDEV_CHANGEMTU, because the device is dying within >> its old netns, who still cares about its mtu change? >> >> Something like the attached patch... > Yes, your patch seems good and I hesitated with something like this. > But I don't see a valid case where the inet[6]dev must be created on a down > interface. I think the patch is valid, even with your patch.
Your patch is more risky because it affects normal CHANGEMTU path, I am not sure if it is correct to not to add idev when it is down either. This is a very unusual path, we don't have to take the risk.
