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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 A7D8EC65BAF for ; Sun, 9 Dec 2018 22:13:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78C0A20661 for ; Sun, 9 Dec 2018 22:13:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 78C0A20661 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728438AbeLIWNp (ORCPT ); Sun, 9 Dec 2018 17:13:45 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:37944 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728414AbeLIWNl (ORCPT ); Sun, 9 Dec 2018 17:13:41 -0500 Received: from pub.yeoldevic.com ([81.174.156.145] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gW734-0002ib-GP; Sun, 09 Dec 2018 21:55:38 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gW72g-0003WI-PU; Sun, 09 Dec 2018 21:55:14 +0000 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, "Sven Eckelmann" , "Antonio Quartulli" , "Marek Lindner" Date: Sun, 09 Dec 2018 21:50:33 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 214/328] batman-adv: Use kref_get for batadv_nc_get_nc_node In-Reply-To: X-SA-Exim-Connect-IP: 81.174.156.145 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 3.16.62-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Sven Eckelmann commit 0de32ceee156787429035c974316f4e5098cf722 upstream. batadv_nc_get_nc_node requires that the caller already has a valid reference for orig_neigh_node. It is therefore not possible that it has an reference counter of 0 and was still given to this function The kref_get function instead WARNs (with debug information) when the reference counter would still be 0. This makes a bug in batman-adv better visible because kref_get_unless_zero would have ignored this problem. Signed-off-by: Sven Eckelmann Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli [bwh: Backported to 3.16: Reference counts are not krefs here, so open- code the equivalent of kref_get()] Signed-off-by: Ben Hutchings --- net/batman-adv/network-coding.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) --- a/net/batman-adv/network-coding.c +++ b/net/batman-adv/network-coding.c @@ -813,8 +813,7 @@ static struct batadv_nc_node if (!nc_node) return NULL; - if (!atomic_inc_not_zero(&orig_neigh_node->refcount)) - goto free; + WARN_ON_ONCE(atomic_inc_return(&orig_neigh_node->refcount) < 2); /* Initialize nc_node */ INIT_LIST_HEAD(&nc_node->list); @@ -840,10 +839,6 @@ static struct batadv_nc_node spin_unlock_bh(lock); return nc_node; - -free: - kfree(nc_node); - return NULL; } /**