From: Florian Westphal <fw@strlen.de>
To: Xin Long <lucien.xin@gmail.com>
Cc: network dev <netdev@vger.kernel.org>,
netfilter-devel@vger.kernel.org, davem@davemloft.net,
pablo@netfilter.org, fw@strlen.de
Subject: Re: [PATCH net] netfilter: unlock xt_table earlier in __do_replace
Date: Fri, 16 Feb 2018 12:02:45 +0100 [thread overview]
Message-ID: <20180216110245.GB31046@breakpoint.cc> (raw)
In-Reply-To: <61f106376f836829d8c283fb4c0cf11567c953bf.1518775496.git.lucien.xin@gmail.com>
Xin Long <lucien.xin@gmail.com> wrote:
> Now it's doing cleanup_entry for oldinfo under the xt_table lock,
> but it's not really necessary. After the replacement job is done
> in xt_replace_table, oldinfo is not used elsewhere any more, and
> it can be freed without xt_table lock safely.
Right.
> The important thing is that rtnl_lock is called in some xt_target
> destroy, which means rtnl_lock, a big lock is used in xt_table
> lock, a smaller one. It usually could be the reason why a dead
> lock may happen.
In which cases do we aquire the xt table mutex from places that hold
rtnl mutex?
> Besides, all xt_target/match checkentry is called out of xt_table
> lock. It's better also to move all cleanup_entry calling out of
> xt_table lock, just as do_replace_finish does for ebtables.
Agree but I don't see how this patch fixes a bug so I would prefer if
this could simmer in nf-next first.
next prev parent reply other threads:[~2018-02-16 11:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-16 10:04 [PATCH net] netfilter: unlock xt_table earlier in __do_replace Xin Long
2018-02-16 11:02 ` Florian Westphal [this message]
2018-02-16 11:25 ` Xin Long
2018-03-05 22:10 ` Pablo Neira Ayuso
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