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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Benjamin LaHaise <bcrl@kvack.org>
Cc: David Miller <davem@davemloft.net>,
	socketcan@hartkopp.net, netdev@vger.kernel.org
Subject: Re: [PATCH net-next] pkt_sched: namespace aware ifb
Date: Sat, 12 Jan 2013 21:49:59 -0800	[thread overview]
Message-ID: <1358056199.20249.2121.camel@edumazet-glaptop> (raw)
In-Reply-To: <20130113035013.GJ5259@kvack.org>

On Sat, 2013-01-12 at 22:50 -0500, Benjamin LaHaise wrote:
> On Sat, Jan 12, 2013 at 07:06:14PM -0800, Eric Dumazet wrote:
> > From: Eric Dumazet <edumazet@google.com>
> > 
> > act_mirred needs to find the current net_ns, and struct net
> > pointer is not provided in the call chain. We run in process
> > context and current->nsproxy->net_ns is the needed pointer.
> ...
> 
> I don't think this is correct.  Going by the call chain, tcf_action_add can 
> be called because of a netlink message, and that netlink message may not be 
> in the same "struct net" as the current process.  It looks like the ->init 
> operation is going to need to have the namespace passed in for this to work 
> correctly.

But it is working in my tests.

I added a WARN and the call stack is :

[  701.522282]  [<ffffffff8108634f>] warn_slowpath_common+0x7f/0xc0
[  701.522284]  [<ffffffff810863aa>] warn_slowpath_null+0x1a/0x20
[  701.522286]  [<ffffffffa00e00e3>] tcf_mirred_init+0x43/0x340 [act_mirred]
[  701.522289]  [<ffffffff81506385>] ? __rtnl_unlock+0x15/0x20
[  701.522293]  [<ffffffff815195e8>] tcf_action_init_1+0x198/0x1e0
[  701.522295]  [<ffffffff815196c8>] tcf_action_init+0x98/0x100
[  701.522298]  [<ffffffff81517f30>] tcf_exts_validate+0x90/0xb0
[  701.522300]  [<ffffffff8151e55b>] u32_set_parms.isra.11+0x3b/0x270
[  701.522303]  [<ffffffff812ffdf0>] ? nla_parse+0x90/0xe0
[  701.522304]  [<ffffffff8151ed16>] u32_change+0x2e6/0x4c0
[  701.522306]  [<ffffffff81518432>] tc_ctl_tfilter+0x4e2/0x720
[  701.522308]  [<ffffffff815064ad>] rtnetlink_rcv_msg+0x11d/0x310
[  701.522310]  [<ffffffff81506390>] ? __rtnl_unlock+0x20/0x20
[  701.522312]  [<ffffffff81522d39>] netlink_rcv_skb+0xa9/0xd0
[  701.522314]  [<ffffffff81503875>] rtnetlink_rcv+0x25/0x40
[  701.522316]  [<ffffffff81522681>] netlink_unicast+0x1b1/0x230
[  701.522317]  [<ffffffff815229fe>] netlink_sendmsg+0x2fe/0x3b0
[  701.522321]  [<ffffffff814dbdf2>] sock_sendmsg+0xd2/0xf0
[  701.522323]  [<ffffffff814dbca0>] ? sock_recvmsg+0xe0/0x100
[  701.522326]  [<ffffffff814dd0f0>] __sys_sendmsg+0x380/0x390
[  701.522329]  [<ffffffff815b20b4>] ? __do_page_fault+0x214/0x460
[  701.522331]  [<ffffffff814df4e9>] sys_sendmsg+0x49/0x90
[  701.522334]  [<ffffffff815b68c2>] system_call_fastpath+0x16/0x1b

Could you elaborate on what could be the problem ?

We hold the RTNL, so I dont think another process could possibly call
tcf_mirred_init()

  reply	other threads:[~2013-01-13  5:50 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-12 13:48 [RFC davem] revert: net: Make skb->skb_iif always track skb->dev Oliver Hartkopp
2013-01-12 18:13 ` Jiri Pirko
2013-01-12 18:40   ` Oliver Hartkopp
2013-01-12 19:37     ` Jiri Pirko
2013-01-12 20:14       ` Oliver Hartkopp
2013-01-12 21:23 ` David Miller
2013-01-12 21:36   ` David Miller
2013-01-13  3:06     ` [PATCH net-next] pkt_sched: namespace aware ifb Eric Dumazet
2013-01-13  3:50       ` Benjamin LaHaise
2013-01-13  5:49         ` Eric Dumazet [this message]
2013-01-13 14:44           ` Jamal Hadi Salim
2013-01-13 16:41             ` Benjamin LaHaise
2013-01-13 16:57               ` Eric Dumazet
2013-01-13 17:25                 ` Jamal Hadi Salim
2013-01-14  5:40                 ` Eric Dumazet
2013-01-13 17:46             ` [PATCH net-next] ifb: dont hard code inet_net use Eric Dumazet
2013-01-14 13:13               ` Jamal Hadi Salim
2013-01-14 15:15                 ` [PATCH net-next] pkt_sched: namespace aware act_mirred Benjamin LaHaise
2013-01-14 20:10                   ` David Miller
2013-01-14 20:13                 ` [PATCH net-next] ifb: dont hard code inet_net use David Miller
2013-01-13 14:59           ` [PATCH net-next] pkt_sched: namespace aware ifb Benjamin LaHaise
2013-01-13 16:35             ` Eric Dumazet
2013-01-13 11:01     ` [RFC davem] revert: net: Make skb->skb_iif always track skb->dev Oliver Hartkopp
2013-01-13 13:20       ` David Miller

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