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Date:   Fri, 5 Feb 2021 11:32:40 -0300
From:   Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
To:     NeilBrown <neilb@suse.de>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Vlad Yasevich <vyasevich@gmail.com>,
        Neil Horman <nhorman@tuxdriver.com>,
        Xin Long <lucien.xin@gmail.com>, linux-kernel@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        linux-sctp@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 3/3] net: fix iteration for sctp transport seq_files
Message-ID: <20210205143240.GA3406@horizon.localdomain>
References: <161248518659.21478.2484341937387294998.stgit@noble1>
 <161248539022.21478.17038123892954492263.stgit@noble1>
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On Fri, Feb 05, 2021 at 11:36:30AM +1100, NeilBrown wrote:
> The sctp transport seq_file iterators take a reference to the transport
> in the ->start and ->next functions and releases the reference in the
> ->show function.  The preferred handling for such resources is to
> release them in the subsequent ->next or ->stop function call.
> 
> Since Commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration
> code and interface") there is no guarantee that ->show will be called
> after ->next, so this function can now leak references.
> 
> So move the sctp_transport_put() call to ->next and ->stop.
> 
> Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
> Reported-by: Xin Long <lucien.xin@gmail.com>
> Signed-off-by: NeilBrown <neilb@suse.de>

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>