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Date: Wed, 19 Oct 2011 00:03:11 -0400 (EDT)
Message-Id: <20111019.000311.1490092497677136273.davem@davemloft.net>
To: mitsuo.hayasaka.hu@hitachi.com
Cc: fubar@us.ibm.com, andy@greyhouse.net, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, yrl.pp-manager.tt@hitachi.com,
        eric.dumazet@gmail.com, xiyou.wangcong@gmail.com
Subject: Re: [PATCH net -v2] [BUGFIX] bonding: use local function pointer
 of bond->recv_probe in bond_handle_frame
From: David Miller <davem@davemloft.net>
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From: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>
Date: Thu, 13 Oct 2011 11:04:29 +0900

> The bond->recv_probe is called in bond_handle_frame() when
> a packet is received, but bond_close() sets it to NULL. So,
> a panic occurs when both functions work in parallel.
> 
> Why this happen:
> After null pointer check of bond->recv_probe, an sk_buff is
> duplicated and bond->recv_probe is called in bond_handle_frame.
> So, a panic occurs when bond_close() is called between the
> check and call of bond->recv_probe.
> 
> Patch:
> This patch uses a local function pointer of bond->recv_probe
> in bond_handle_frame(). So, it can avoid the null pointer
> dereference.
> 
> 
> Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>
> Cc: Jay Vosburgh <fubar@us.ibm.com>
> Cc: Andy Gospodarek <andy@greyhouse.net>
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: WANG Cong <xiyou.wangcong@gmail.com>

Bonding folks please review this, thanks.