From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760574AbZAWBWM (ORCPT ); Thu, 22 Jan 2009 20:22:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756770AbZAWBPI (ORCPT ); Thu, 22 Jan 2009 20:15:08 -0500 Received: from kroah.org ([198.145.64.141]:50566 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1760212AbZAWBO6 (ORCPT ); Thu, 22 Jan 2009 20:14:58 -0500 Date: Thu, 22 Jan 2009 17:12:13 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , Willy Tarreau , Rodrigo Rubira Branco , Jake Edge , Eugene Teo , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jarek Poplawski , "David S. Miller" Subject: [patch 21/46] pkt_sched: cls_u32: Fix locking in u32_change() Message-ID: <20090123011213.GV19756@kroah.com> References: <20090123010651.683741823@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="pkt_sched-cls_u32-fix-locking-in-u32_change.patch" In-Reply-To: <20090123011110.GA19756@kroah.com> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.28-stable review patch. If anyone has any objections, please let us know. ------------------ From: Jarek Poplawski [ Upstream commit: 6f57321422e0d359e83c978c2b03db77b967b7d5 ] New nodes are inserted in u32_change() under rtnl_lock() with wmb(), so without tcf_tree_lock() like in other classifiers (e.g. cls_fw). This isn't enough without rmb() on the read side, but on the other hand adding such barriers doesn't give any savings, so the lock is added instead. Reported-by: m0sia Signed-off-by: Jarek Poplawski Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/cls_u32.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -637,8 +637,9 @@ static int u32_change(struct tcf_proto * break; n->next = *ins; - wmb(); + tcf_tree_lock(tp); *ins = n; + tcf_tree_unlock(tp); *arg = (unsigned long)n; return 0;