From patchwork Fri Jan 30 07:46:28 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patrick McHardy X-Patchwork-Id: 434766 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 4E32D140161 for ; Fri, 30 Jan 2015 18:47:38 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755294AbbA3Hqs (ORCPT ); Fri, 30 Jan 2015 02:46:48 -0500 Received: from stinky.trash.net ([213.144.137.162]:34109 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753418AbbA3Hqq (ORCPT ); Fri, 30 Jan 2015 02:46:46 -0500 Received: from acer.localdomain.localdomain (localhost [127.0.0.1]) by stinky.trash.net (Postfix) with ESMTP id C213B9D2E2; Fri, 30 Jan 2015 08:46:43 +0100 (MET) From: Patrick McHardy To: herbert@gondor.apana.org.au Cc: tgraf@suug.ch, davem@davemloft.net, David.Laight@ACULAB.COM, ying.xue@windriver.com, paulmck@linux.vnet.ibm.com, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org Subject: [PATCH 3/9] nftables: nft_rbtree: fix locking Date: Fri, 30 Jan 2015 07:46:28 +0000 Message-Id: <1422603994-5836-4-git-send-email-kaber@trash.net> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1422603994-5836-1-git-send-email-kaber@trash.net> References: <1422603994-5836-1-git-send-email-kaber@trash.net> Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Fix a race condition and unnecessary locking: * the root rb_node must only be accessed under the lock in nft_rbtree_lookup() * the lock is not needed in lookup functions in netlink contexts Signed-off-by: Patrick McHardy --- net/netfilter/nft_rbtree.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/net/netfilter/nft_rbtree.c b/net/netfilter/nft_rbtree.c index 46214f2..417796f 100644 --- a/net/netfilter/nft_rbtree.c +++ b/net/netfilter/nft_rbtree.c @@ -37,10 +37,11 @@ static bool nft_rbtree_lookup(const struct nft_set *set, { const struct nft_rbtree *priv = nft_set_priv(set); const struct nft_rbtree_elem *rbe, *interval = NULL; - const struct rb_node *parent = priv->root.rb_node; + const struct rb_node *parent; int d; spin_lock_bh(&nft_rbtree_lock); + parent = priv->root.rb_node; while (parent != NULL) { rbe = rb_entry(parent, struct nft_rbtree_elem, node); @@ -158,7 +159,6 @@ static int nft_rbtree_get(const struct nft_set *set, struct nft_set_elem *elem) struct nft_rbtree_elem *rbe; int d; - spin_lock_bh(&nft_rbtree_lock); while (parent != NULL) { rbe = rb_entry(parent, struct nft_rbtree_elem, node); @@ -173,11 +173,9 @@ static int nft_rbtree_get(const struct nft_set *set, struct nft_set_elem *elem) !(rbe->flags & NFT_SET_ELEM_INTERVAL_END)) nft_data_copy(&elem->data, rbe->data); elem->flags = rbe->flags; - spin_unlock_bh(&nft_rbtree_lock); return 0; } } - spin_unlock_bh(&nft_rbtree_lock); return -ENOENT; } @@ -190,7 +188,6 @@ static void nft_rbtree_walk(const struct nft_ctx *ctx, struct nft_set_elem elem; struct rb_node *node; - spin_lock_bh(&nft_rbtree_lock); for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) { if (iter->count < iter->skip) goto cont; @@ -203,14 +200,11 @@ static void nft_rbtree_walk(const struct nft_ctx *ctx, elem.flags = rbe->flags; iter->err = iter->fn(ctx, set, iter, &elem); - if (iter->err < 0) { - spin_unlock_bh(&nft_rbtree_lock); + if (iter->err < 0) return; - } cont: iter->count++; } - spin_unlock_bh(&nft_rbtree_lock); } static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[])