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From: Ivan Vecera <ivecera@redhat.com>
To: Saeed Mahameed <saeed@kernel.org>
Cc: netdev@vger.kernel.org, Jiri Pirko <jiri@resnulli.us>
Subject: Re: [PATCH net] team: fix deadlock during setting of MTU
Date: Wed, 20 Jan 2021 13:23:00 +0100	[thread overview]
Message-ID: <20210120132300.757b91b3@ceranb> (raw)
In-Reply-To: <20210115092405.29e8ff8f@ceranb>

On Fri, 15 Jan 2021 09:24:05 +0100
Ivan Vecera <ivecera@redhat.com> wrote:

> > 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


      reply	other threads:[~2021-01-20 12:53 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-14 11:55 [PATCH net] team: fix deadlock during setting of MTU Ivan Vecera
2021-01-15  0:34 ` Saeed Mahameed
2021-01-15  8:24   ` Ivan Vecera
2021-01-20 12:23     ` Ivan Vecera [this message]

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