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From: ebiederm@xmission.com (Eric W. Biederman)
To: Johannes Berg <johannes@sipsolutions.net>
Cc: John Linville <linville@tuxdriver.com>,
	Netdev <netdev@vger.kernel.org>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	"Eric W. Biederman" <ebiederm@aristanetworks.com>,
	Alexey Dobriyan <adobriyan@gmail.com>
Subject: Re: [PATCH] wireless extensions: play with netns
Date: Wed, 17 Jun 2009 16:54:12 -0700	[thread overview]
Message-ID: <m17hzato0r.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <1245282099.31588.69.camel@johannes.local> (Johannes Berg's message of "Thu\, 18 Jun 2009 01\:41\:38 +0200")

Johannes Berg <johannes@sipsolutions.net> writes:

> On Wed, 2009-06-17 at 16:24 -0700, Eric W. Biederman wrote:
>
>> > So it looks like I can also use rcu_read_lock(), but there's no
>> > for_each_net_rcu(), should there be?
>> 
>> I'm not using rcu safe list manipulation.  What makes it look like
>> rcu_read_lock() is safe?
>
> Indeed. I was looking at rcu_barrier() only. How about the patch below?
>
> johannes
>
> Subject: net: make namespace iteration possible under RCU
>
> We already call rcu_barrier(), so all we need to take
> care of is using proper RCU list add/del primitives.

This of course gives you a network namespace that can be found by for_each_net rcu
while the per net exit functions are running.  I think that opens up to races
that I don't want to think about.

I still haven't tracked down how I am occasionally getting time wait sockets
with an invalid network namespace.

Eric

  parent reply	other threads:[~2009-06-17 23:54 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-17 18:24 [PATCH] wireless extensions: play with netns Johannes Berg
2009-06-17 20:46 ` Eric W. Biederman
2009-06-17 20:50   ` Johannes Berg
2009-06-17 21:40   ` [PATCH v2] wireless extensions: make netns aware Johannes Berg
2009-06-17 22:14   ` [PATCH] wireless extensions: play with netns Johannes Berg
2009-06-17 23:24     ` Eric W. Biederman
2009-06-17 23:41       ` Johannes Berg
2009-06-17 23:45         ` Johannes Berg
2009-06-18  0:27           ` Eric W. Biederman
2009-06-18  0:35             ` Johannes Berg
2009-06-17 23:54         ` Eric W. Biederman [this message]
2009-06-18  0:02           ` Johannes Berg
2009-06-18  0:30             ` Eric W. Biederman
2009-06-18  0:39               ` Johannes Berg
2009-06-18  1:12                 ` Eric W. Biederman

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