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Date: Wed, 10 Feb 2021 12:12:57 +0200
From: Ido Schimmel <idosch@idosch.org>
Message-ID: <20210210101257.GA287766@shredder.lan>
References: <20210210091445.741269-1-olteanv@gmail.com>
 <20210210091445.741269-8-olteanv@gmail.com>
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In-Reply-To: <20210210091445.741269-8-olteanv@gmail.com>
Subject: Re: [Bridge] [PATCH v3 net-next 07/11] net: prep switchdev drivers
 for concurrent SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS
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To: Vladimir Oltean <olteanv@gmail.com>
Cc: Ivan Vecera <ivecera@redhat.com>, Andrew Lunn <andrew@lunn.ch>, Alexandre Belloni <alexandre.belloni@bootlin.com>, Florian Fainelli <f.fainelli@gmail.com>, Jiri Pirko <jiri@resnulli.us>, Vadym Kochan <vkochan@marvell.com>, linux-omap@vger.kernel.org, netdev@vger.kernel.org, bridge@lists.linux-foundation.org, Ioana Ciornei <ioana.ciornei@nxp.com>, linux-kernel@vger.kernel.org, Vivien Didelot <vivien.didelot@gmail.com>, Taras Chornyi <tchornyi@marvell.com>, Claudiu Manoil <claudiu.manoil@nxp.com>, Grygorii Strashko <grygorii.strashko@ti.com>, Nikolay Aleksandrov <nikolay@nvidia.com>, Roopa Prabhu <roopa@nvidia.com>, Jakub Kicinski <kuba@kernel.org>, UNGLinuxDriver@microchip.com, "David S. Miller" <davem@davemloft.net>

On Wed, Feb 10, 2021 at 11:14:41AM +0200, Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.oltean@nxp.com>
> 
> Because the bridge will start offloading SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS
> while not serialized by any lock such as the br->lock spinlock, existing
> drivers that treat that attribute and cache the brport flags might no
> longer work correctly.

Can you explain the race? This notification is sent from sysfs/netlink
call path, both of which take rtnl.