From: Vladimir Oltean <olteanv@gmail.com>
To: Ido Schimmel <idosch@idosch.org>
Cc: Jakub Kicinski <kuba@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Andrew Lunn <andrew@lunn.ch>,
Vivien Didelot <vivien.didelot@gmail.com>,
Florian Fainelli <f.fainelli@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
bridge@lists.linux-foundation.org,
Roopa Prabhu <roopa@nvidia.com>,
Nikolay Aleksandrov <nikolay@nvidia.com>,
Jiri Pirko <jiri@resnulli.us>,
Claudiu Manoil <claudiu.manoil@nxp.com>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
UNGLinuxDriver@microchip.com, Vadym Kochan <vkochan@marvell.com>,
Taras Chornyi <tchornyi@marvell.com>,
Grygorii Strashko <grygorii.strashko@ti.com>,
Ioana Ciornei <ioana.ciornei@nxp.com>,
Ivan Vecera <ivecera@redhat.com>,
linux-omap@vger.kernel.org
Subject: Re: [PATCH v3 net-next 07/11] net: prep switchdev drivers for concurrent SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS
Date: Wed, 10 Feb 2021 12:23:28 +0200 [thread overview]
Message-ID: <20210210102328.7jpzlobpwotdo63z@skbuf> (raw)
In-Reply-To: <20210210101257.GA287766@shredder.lan>
On Wed, Feb 10, 2021 at 12:12:57PM +0200, Ido Schimmel wrote:
> 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.
Replying here to both you and Nikolay: there isn't any race, sorry, I
missed the fact that brport_store takes the rtnl_mutex and by extension
I thought that RTM_SETLINK runs unlocked too, without really checking.
Well, at least that's good news, the implementation can be a lot more
straightforward then...
WARNING: multiple messages have this Message-ID (diff)
From: Vladimir Oltean <olteanv@gmail.com>
To: Ido Schimmel <idosch@idosch.org>
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>
Subject: Re: [Bridge] [PATCH v3 net-next 07/11] net: prep switchdev drivers for concurrent SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS
Date: Wed, 10 Feb 2021 12:23:28 +0200 [thread overview]
Message-ID: <20210210102328.7jpzlobpwotdo63z@skbuf> (raw)
In-Reply-To: <20210210101257.GA287766@shredder.lan>
On Wed, Feb 10, 2021 at 12:12:57PM +0200, Ido Schimmel wrote:
> 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.
Replying here to both you and Nikolay: there isn't any race, sorry, I
missed the fact that brport_store takes the rtnl_mutex and by extension
I thought that RTM_SETLINK runs unlocked too, without really checking.
Well, at least that's good news, the implementation can be a lot more
straightforward then...
next prev parent reply other threads:[~2021-02-10 10:36 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-10 9:14 [PATCH v3 net-next 00/11] Cleanup in brport flags switchdev offload for DSA Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-10 9:14 ` [PATCH v3 net-next 01/11] net: switchdev: propagate extack to port attributes Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-11 4:12 ` Florian Fainelli
2021-02-11 4:12 ` [Bridge] " Florian Fainelli
2021-02-10 9:14 ` [PATCH v3 net-next 02/11] net: bridge: offload all port flags at once in br_setport Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-10 9:14 ` [PATCH v3 net-next 03/11] net: bridge: don't print in br_switchdev_set_port_flag Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-10 9:14 ` [PATCH v3 net-next 04/11] net: dsa: configure proper brport flags when ports leave the bridge Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-11 4:16 ` Florian Fainelli
2021-02-11 4:16 ` [Bridge] " Florian Fainelli
2021-02-10 9:14 ` [PATCH v3 net-next 05/11] net: squash switchdev attributes PRE_BRIDGE_FLAGS and BRIDGE_FLAGS Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-10 9:14 ` [PATCH v3 net-next 06/11] net: dsa: kill .port_egress_floods overengineering Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-11 4:18 ` Florian Fainelli
2021-02-11 4:18 ` [Bridge] " Florian Fainelli
2021-02-10 9:14 ` [PATCH v3 net-next 07/11] net: prep switchdev drivers for concurrent SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-10 10:12 ` Ido Schimmel
2021-02-10 10:12 ` [Bridge] " Ido Schimmel
2021-02-10 10:23 ` Vladimir Oltean [this message]
2021-02-10 10:23 ` Vladimir Oltean
2021-02-10 23:34 ` David Miller
2021-02-10 23:34 ` [Bridge] " David Miller
2021-02-10 9:14 ` [PATCH v3 net-next 08/11] net: bridge: put SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS on the blocking call chain Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-10 10:14 ` Nikolay Aleksandrov
2021-02-10 10:14 ` [Bridge] " Nikolay Aleksandrov
2021-02-10 9:14 ` [PATCH v3 net-next 09/11] net: mscc: ocelot: use separate flooding PGID for broadcast Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-11 4:19 ` Florian Fainelli
2021-02-11 4:19 ` [Bridge] " Florian Fainelli
2021-02-10 9:14 ` [PATCH v3 net-next 10/11] net: mscc: ocelot: offload bridge port flags to device Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-11 4:20 ` Florian Fainelli
2021-02-11 4:20 ` [Bridge] " Florian Fainelli
2021-02-10 9:14 ` [PATCH v3 net-next 11/11] net: dsa: sja1105: " Vladimir Oltean
2021-02-10 9:14 ` [Bridge] " Vladimir Oltean
2021-02-10 10:31 ` [PATCH v3 net-next 00/11] Cleanup in brport flags switchdev offload for DSA Nikolay Aleksandrov
2021-02-10 10:31 ` [Bridge] " Nikolay Aleksandrov
2021-02-10 10:45 ` Vladimir Oltean
2021-02-10 10:45 ` [Bridge] " Vladimir Oltean
2021-02-10 10:52 ` Nikolay Aleksandrov
2021-02-10 10:52 ` [Bridge] " Nikolay Aleksandrov
2021-02-10 11:01 ` Vladimir Oltean
2021-02-10 11:01 ` [Bridge] " Vladimir Oltean
2021-02-10 11:05 ` Nikolay Aleksandrov
2021-02-10 11:05 ` [Bridge] " Nikolay Aleksandrov
2021-02-10 12:01 ` Vladimir Oltean
2021-02-10 12:01 ` [Bridge] " Vladimir Oltean
2021-02-10 12:10 ` Nikolay Aleksandrov
2021-02-10 12:10 ` [Bridge] " Nikolay Aleksandrov
2021-02-10 12:21 ` Ido Schimmel
2021-02-10 12:21 ` [Bridge] " Ido Schimmel
2021-02-10 12:29 ` Vladimir Oltean
2021-02-10 12:29 ` [Bridge] " Vladimir Oltean
2021-02-10 12:38 ` Ido Schimmel
2021-02-10 12:38 ` [Bridge] " Ido Schimmel
2021-02-10 12:55 ` Vladimir Oltean
2021-02-10 12:55 ` [Bridge] " Vladimir Oltean
2021-02-10 12:59 ` Ido Schimmel
2021-02-10 12:59 ` [Bridge] " Ido Schimmel
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