From patchwork Mon Mar 7 22:35:54 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 593462 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3AA0F140271; Tue, 8 Mar 2016 09:45:04 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ad3td-0004Hp-3V; Mon, 07 Mar 2016 22:45:01 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1ad3kt-000827-4h for kernel-team@lists.ubuntu.com; Mon, 07 Mar 2016 22:35:59 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1ad3ks-0007e6-MD; Mon, 07 Mar 2016 22:35:58 +0000 Received: from kamal by fourier with local (Exim 4.86) (envelope-from ) id 1ad3kq-0000pQ-0F; Mon, 07 Mar 2016 14:35:56 -0800 From: Kamal Mostafa To: Eric Dumazet Subject: [4.2.y-ckt stable] Patch "ipv6: fix a lockdep splat" has been added to the 4.2.y-ckt tree Date: Mon, 7 Mar 2016 14:35:54 -0800 Message-Id: <1457390154-3126-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 X-Extended-Stable: 4.2 Cc: Dave Jones , Kamal Mostafa , "David S . Miller" , Hannes Frederic Sowa , kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled ipv6: fix a lockdep splat to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt5. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From e1f8ce7f75105cd04395e168a53c2a7c0d4b87b8 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 2 Feb 2016 17:55:01 -0800 Subject: ipv6: fix a lockdep splat [ 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: Kamal Mostafa --- net/ipv6/ip6_flowlabel.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) -- 2.7.0 diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c index 1f9ebe3..dc2db4f 100644 --- a/net/ipv6/ip6_flowlabel.c +++ b/net/ipv6/ip6_flowlabel.c @@ -540,12 +540,13 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen) } 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);