Re: [PATCH] wireless extensions: play with netns

On Wed, 2009-06-17 at 16:54 -0700, Eric W. Biederman wrote:

quoted

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.

Indeed. Can we move the rcu_barrier() up? Or we could insert a
synchronize_rcu() (which is sufficient for rcu_read_lock) before the
exit functions are run?

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

Ouch.

johannes