From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gao feng <gaofeng@cn.fujitsu.com>
Subject: Re: [PATCH] ulog: add protection when remove ipt_ULOG
Date: Mon, 18 Feb 2013 11:57:36 +0800
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Cc: netfilter-devel@vger.kernel.org
To: Pablo Neira Ayuso <pablo@netfilter.org>
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Hi Pablo,

On 2013/02/08 02:27, Pablo Neira Ayuso wrote:
> Hi Gao,
> 
> On Tue, Feb 05, 2013 at 09:57:30AM +0800, Gao feng wrote:
>> We should add a lock protection when we free the skb,
>> because it maybe used by ipt_ulog_packet right now.
> 
> Did you hit a reproducible crash?
> 

I didn't.
I looked at the ebt_ulog.c and found ebt_ulog_fini
uses the spin lock to protect the ulog_buff's skb.


> I think this is very unlikely to happen. The removal of the module
> happens in user-context and the entire path to build and deliver the
> skb to user-space is protected is under spin_lock_bh, so scheduling
> is not possible.
>

Doesn't spin_lock_bh only disable local cpu's bottom-half?
the task that remove the modules can run on other cpus at the same time.
I'm wrong?