From: "Paul E. McKenney" Subject: Re: [PATCH 4/5] sctp: protocol.c call rcu_barrier() on unload. Date: Mon, 8 Jun 2009 09:22:27 -0700 Message-ID: <20090608162227.GE6961@linux.vnet.ibm.com> References: <20090608130959.10052.54590.stgit@localhost> <20090608131143.10052.96470.stgit@localhost> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "David S. Miller" , 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: <20090608131143.10052.96470.stgit@localhost> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Jun 08, 2009 at 03:11:43PM +0200, Jesper Dangaard Brouer wrote: > On module unload call rcu_barrier(), this is needed as synchronize_rcu() > is not strong enough. The kmem_cache_destroy() does invoke > synchronize_rcu() but it does not provide same protection. Good, looks like sctp_v4_del_protocol() invokes call_rcu(), which the rcu_barrier() would then wait for. And it looks like sctp_v6_del_protocol() does the same for IPv6. Reviewed_by: Paul E. McKenney > Signed-off-by: Jesper Dangaard Brouer > --- > > net/sctp/protocol.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c > index cb2c50d..79cbd47 100644 > --- a/net/sctp/protocol.c > +++ b/net/sctp/protocol.c > @@ -1370,6 +1370,8 @@ SCTP_STATIC __exit void sctp_exit(void) > sctp_proc_exit(); > cleanup_sctp_mibs(); > > + rcu_barrier(); /* Wait for completion of call_rcu()'s */ > + > kmem_cache_destroy(sctp_chunk_cachep); > kmem_cache_destroy(sctp_bucket_cachep); > } >