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
WARNING: multiple messages have this Message-ID (diff)
From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)
To: Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
Cc: John Linville <linville-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org>,
Netdev <netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
linux-wireless
<linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"Eric W. Biederman"
<ebiederm-BGArkANP9klv6pq1l3V1OdBPR1lH4CV8@public.gmane.org>,
Alexey Dobriyan
<adobriyan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
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-YfaajirXv2244ywRPIzf9A@public.gmane.org> (Johannes Berg's message of "Thu\, 18 Jun 2009 01\:41\:38 +0200")
Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org> 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
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next prev parent reply other threads:[~2009-06-17 23:54 UTC|newest]
Thread overview: 26+ 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 18:24 ` Johannes Berg
2009-06-17 20:46 ` Eric W. Biederman
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 21:40 ` Johannes Berg
2009-06-17 22:14 ` [PATCH] wireless extensions: play with netns Johannes Berg
2009-06-17 22:14 ` Johannes Berg
2009-06-17 23:24 ` Eric W. Biederman
2009-06-17 23:24 ` Eric W. Biederman
2009-06-17 23:41 ` Johannes Berg
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 0:27 ` Eric W. Biederman
2009-06-18 0:35 ` Johannes Berg
2009-06-17 23:54 ` Eric W. Biederman [this message]
2009-06-17 23:54 ` Eric W. Biederman
2009-06-18 0:02 ` Johannes Berg
2009-06-18 0:02 ` Johannes Berg
2009-06-18 0:30 ` Eric W. Biederman
2009-06-18 0:30 ` Eric W. Biederman
2009-06-18 0:39 ` Johannes Berg
2009-06-18 0:39 ` Johannes Berg
2009-06-18 1:12 ` Eric W. Biederman
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