Re: [PATCH net] team: fix deadlock during setting of MTU

On Fri, 15 Jan 2021 09:24:05 +0100
Ivan Vecera [off-list ref] wrote:

quoted

according to your explanation in the commit message the team->lock
mutex will be also taken under this rcu lock, so this is bad even
if dev_set_mtu does not sleep.
  

Hmm, you are right... btw do we need to take this mutex at this place?

team_change_mtu() is protected by RTNL, team_device_event() as a netdevice
notifier as well... and team_{add,del}_slave() that modify port list
also.

Thoughts?

After private discussion with Jiri, this is no-go as he would not like to
introduce a dependency on RTNL into team driver. The other solution is
to postpone features calculation in certain cases... the patch follows.

Ivan