netdev - Re: [PATCH net v2] net: bridge: Fix locking in br_fdb_find

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Message-Id: <20180608.200009.1607578368137840763.davem@davemloft.net>
Date:   Fri, 08 Jun 2018 20:00:09 -0400 (EDT)
From:   David Miller <davem@...emloft.net>
To:     petrm@...lanox.com
Cc:     bridge@...ts.linux-foundation.org, netdev@...r.kernel.org,
        stephen@...workplumber.org
Subject: Re: [PATCH net v2] net: bridge: Fix locking in br_fdb_find_port()

From: Petr Machata <petrm@...lanox.com>
Date: Fri, 08 Jun 2018 15:11:47 +0200

> Callers of br_fdb_find() need to hold the hash lock, which
> br_fdb_find_port() doesn't do. However, since br_fdb_find_port() is not
> doing any actual FDB manipulation, the hash lock is not really needed at
> all. So convert to br_fdb_find_rcu(), surrounded by rcu_read_lock() /
> _unlock() pair.
> 
> The device pointer copied from inside the FDB entry is then kept alive
> by the RTNL lock, which br_fdb_find_port() asserts.
> 
> Fixes: 4d4fd36126d6 ("net: bridge: Publish bridge accessor functions")
> Signed-off-by: Petr Machata <petrm@...lanox.com>

Applied, thank you.