From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail177-1.suw61.mandrillapp.com ([198.2.177.1]:23733 "EHLO mail177-1.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755055AbcCAXyQ (ORCPT ); Tue, 1 Mar 2016 18:54:16 -0500 Received: from pmta06.mandrill.prod.suw01.rsglab.com (127.0.0.1) by mail177-1.suw61.mandrillapp.com id hqolqg22rtku for ; Tue, 1 Mar 2016 23:53:49 +0000 (envelope-from ) From: Greg Kroah-Hartman Subject: [PATCH 4.4 018/342] ipv6: fix a lockdep splat To: Cc: Greg Kroah-Hartman , , Dave Jones , Eric Dumazet , Hannes Frederic Sowa , "David S. Miller" Message-Id: <20160301234528.576362343@linuxfoundation.org> In-Reply-To: <20160301234527.990448862@linuxfoundation.org> References: <20160301234527.990448862@linuxfoundation.org> Date: Tue, 01 Mar 2016 23:53:49 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 44c3d0c1c0a880354e9de5d94175742e2c7c9683 ] Silence lockdep false positive about rcu_dereference() being used in the wrong context. First one should use rcu_dereference_protected() as we own the spinlock. Second one should be a normal assignation, as no barrier is needed. Fixes: 18367681a10bd ("ipv6 flowlabel: Convert np->ipv6_fl_list to RCU.") Reported-by: Dave Jones Signed-off-by: Eric Dumazet Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_flowlabel.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/net/ipv6/ip6_flowlabel.c +++ b/net/ipv6/ip6_flowlabel.c @@ -540,12 +540,13 @@ int ipv6_flowlabel_opt(struct sock *sk, } spin_lock_bh(&ip6_sk_fl_lock); for (sflp = &np->ipv6_fl_list; - (sfl = rcu_dereference(*sflp)) != NULL; + (sfl = rcu_dereference_protected(*sflp, + lockdep_is_held(&ip6_sk_fl_lock))) != NULL; sflp = &sfl->next) { if (sfl->fl->label == freq.flr_label) { if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK)) np->flow_label &= ~IPV6_FLOWLABEL_MASK; - *sflp = rcu_dereference(sfl->next); + *sflp = sfl->next; spin_unlock_bh(&ip6_sk_fl_lock); fl_release(sfl->fl); kfree_rcu(sfl, rcu);