netdev - Re: [patch net] switchdev: Require RTNL mutex to be held when sending FDB notifications

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Message-Id: <20160128.162215.1495832301297951482.davem@davemloft.net>
Date:	Thu, 28 Jan 2016 16:22:15 -0800 (PST)
From:	David Miller <davem@...emloft.net>
To:	jiri@...nulli.us
Cc:	netdev@...r.kernel.org, idosch@...lanox.com, eladr@...lanox.com,
	yotamg@...lanox.com, ogerlitz@...lanox.com,
	stephen@...workplumber.org, sfeldma@...il.com
Subject: Re: [patch net] switchdev: Require RTNL mutex to be held when
 sending FDB notifications

From: Jiri Pirko <jiri@...nulli.us>
Date: Wed, 27 Jan 2016 15:16:43 +0100

> From: Ido Schimmel <idosch@...lanox.com>
> 
> When switchdev drivers process FDB notifications from the underlying
> device they resolve the netdev to which the entry points to and notify
> the bridge using the switchdev notifier.
> 
> However, since the RTNL mutex is not held there is nothing preventing
> the netdev from disappearing in the middle, which will cause
> br_switchdev_event() to dereference a non-existing netdev.
> 
> Make switchdev drivers hold the lock at the beginning of the
> notification processing session and release it once it ends, after
> notifying the bridge.
> 
> Also, remove switchdev_mutex and fdb_lock, as they are no longer needed
> when RTNL mutex is held.
> 
> Fixes: 03bf0c281234 ("switchdev: introduce switchdev notifier")
> Signed-off-by: Ido Schimmel <idosch@...lanox.com>
> Signed-off-by: Jiri Pirko <jiri@...lanox.com>

Applied and queued up for -stable, thanks Jiri.