[PATCH] netns: Simplify the network namespace list locking rules.

David Miller davem at davemloft.net
Wed Sep 26 22:40:22 PDT 2007


From: ebiederm at xmission.com (Eric W. Biederman)
Date: Wed, 26 Sep 2007 21:54:47 -0600

> 
> Denis V. Lunev <den at sw.ru> noticed that the locking rules
> for the network namespace list are over complicated and broken.
> 
> In particular the current register_netdev_notifier currently
> does not take any lock making the for_each_net iteration racy
> with network namespace creation and destruction. Oops.
> 
> The fact that we need to use for_each_net in rtnl_unlock() when
> the rtnetlink support becomes per network namespace makes designing
> the proper locking tricky.  In addition we need to be able to call
> rtnl_lock() and rtnl_unlock() when we have the net_mutex held.
> 
> After thinking about it and looking at the alternatives carefully
> it looks like the simplest and most maintainable solution is
> to remove net_list_mutex altogether, and to use the rtnl_mutex instead.
> 
> Signed-off-by: Eric W. Biederman <ebiederm at xmission.com>

Applied, thanks Eric.


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