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Subject: Re: sctp: hang in sctp_remaddr_seq_show
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>, Sasha Levin <sasha.levin@oracle.com>,
        sri@us.ibm.com, "David S. Miller" <davem@davemloft.net>,
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Date: Mon, 18 Mar 2013 13:48:48 -0700
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On Mon, 2013-03-18 at 16:32 -0400, Neil Horman wrote:

> Vlads, right.  We need to grab the rcu lock before the read lock, but we should
> probably use the rcu_read_lock_bh variant, since we're going to disable bottom
> halves anyway.
> Neil

rcu_read_lock_bh() and {local_bh_disable();rcu_read_lock();} have quite
different semantics.

If you use rcu_read_lock_bh(), you also need to change rcu_dereference()
calls to rcu_dereference_bh() variant.