Le 06/07/2017 à 20:16, Cong Wang a écrit : > 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. Why would it be needed to add this idev on a down interface? If idev wasn't there I don't see why changing the mtu would justify to create this idev.
> > This is a very unusual path, we don't have to take the risk. I still think that this approach is better for two reasons: - we don't know if another path like this exists (need an audit) and it would be easy to add one again by side effect in the future; - the patch is easy to backport in older kernel. Regards, Nicolas
