From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DBEB3C4360C for ; Wed, 2 Oct 2019 19:12:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BB669207FF for ; Wed, 2 Oct 2019 19:12:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729588AbfJBTMG (ORCPT ); Wed, 2 Oct 2019 15:12:06 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35592 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729199AbfJBTIM (ORCPT ); Wed, 2 Oct 2019 15:08:12 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iFjyr-000368-MN; Wed, 02 Oct 2019 20:08:09 +0100 Received: from ben by deadeye with local (Exim 4.92.1) (envelope-from ) id 1iFjyo-0003e2-N4; Wed, 02 Oct 2019 20:08:06 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "David S. Miller" , "Eric Dumazet" , "Willem de Bruijn" Date: Wed, 02 Oct 2019 20:06:51 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 52/87] ipv6: flowlabel: fl6_sock_lookup() must use atomic_inc_not_zero In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.75-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit 65a3c497c0e965a552008db8bc2653f62bc925a1 upstream. Before taking a refcount, make sure the object is not already scheduled for deletion. Same fix is needed in ipv6_flowlabel_opt() Fixes: 18367681a10b ("ipv6 flowlabel: Convert np->ipv6_fl_list to RCU.") Signed-off-by: Eric Dumazet Cc: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/ipv6/ip6_flowlabel.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/net/ipv6/ip6_flowlabel.c +++ b/net/ipv6/ip6_flowlabel.c @@ -255,9 +255,9 @@ struct ip6_flowlabel * fl6_sock_lookup(s rcu_read_lock_bh(); for_each_sk_fl_rcu(np, sfl) { struct ip6_flowlabel *fl = sfl->fl; - if (fl->label == label) { + + if (fl->label == label && atomic_inc_not_zero(&fl->users)) { fl->lastuse = jiffies; - atomic_inc(&fl->users); rcu_read_unlock_bh(); return fl; } @@ -619,7 +619,8 @@ int ipv6_flowlabel_opt(struct sock *sk, goto done; } fl1 = sfl->fl; - atomic_inc(&fl1->users); + if (!atomic_inc_not_zero(&fl1->users)) + fl1 = NULL; break; } }