From: Patrick McHardy Subject: Re: [PATCH 0/5] We must use rcu_barrier() on module unload Date: Mon, 08 Jun 2009 16:00:29 +0200 Message-ID: <4A2D197D.4060804@trash.net> References: <20090608130959.10052.54590.stgit@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Cc: "David S. Miller" , "Paul E. McKenney" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, urs.thuermann@volkswagen.de, oliver.hartkopp@volkswagen.de, wg@grandegger.com, vladislav.yasevich@hp.com, sri@us.ibm.com, linux-sctp@vger.kernel.org, Trond.Myklebust@netapp.com, linux-nfs@vger.kernel.org, netfilter-devel@vger.kernel.org To: Jesper Dangaard Brouer Return-path: In-Reply-To: <20090608130959.10052.54590.stgit@localhost> Sender: netfilter-devel-owner@vger.kernel.org List-ID: Jesper Dangaard Brouer wrote: > If an unloadable module uses RCU callbacks, it need to use > rcu_barrier() so that the module may be safely unloaded. > > While hacking on a netfilter module of my own, I learned the > importance of calling rcu_barrier() instead of only a > synchronize_rcu() on module unload (iif using any call_rcu() > callbacks). synchronize_rcu() does wait for a grace period to > elapse, but it does not wait for the callbacks to complete. > > ... > I have made a patch for each individual module, so objections can be > made on a per module basis. I have Cc'ed all of the patches to the > maintainers of each module (according to the MAINTAINERS file). Acked-by: Patrick McHardy for patches 1 and 2, good catch.