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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30D9BC07E8A for ; Tue, 15 Aug 2023 22:31:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240303AbjHOWaz (ORCPT ); Tue, 15 Aug 2023 18:30:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240301AbjHOWa0 (ORCPT ); Tue, 15 Aug 2023 18:30:26 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0AD81FEE; Tue, 15 Aug 2023 15:30:25 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1qW2YP-0004Zh-T9; Wed, 16 Aug 2023 00:30:21 +0200 From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Subject: [PATCH net 1/9] netfilter: nf_tables: fix false-positive lockdep splat Date: Wed, 16 Aug 2023 00:29:51 +0200 Message-ID: <20230815223011.7019-2-fw@strlen.de> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230815223011.7019-1-fw@strlen.de> References: <20230815223011.7019-1-fw@strlen.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org ->abort invocation may cause splat on debug kernels: WARNING: suspicious RCU usage net/netfilter/nft_set_pipapo.c:1697 suspicious rcu_dereference_check() usage! [..] rcu_scheduler_active = 2, debug_locks = 1 1 lock held by nft/133554: [..] (nft_net->commit_mutex){+.+.}-{3:3}, at: nf_tables_valid_genid [..] lockdep_rcu_suspicious+0x1ad/0x260 nft_pipapo_abort+0x145/0x180 __nf_tables_abort+0x5359/0x63d0 nf_tables_abort+0x24/0x40 nfnetlink_rcv+0x1a0a/0x22c0 netlink_unicast+0x73c/0x900 netlink_sendmsg+0x7f0/0xc20 ____sys_sendmsg+0x48d/0x760 Transaction mutex is held, so parallel updates are not possible. Switch to _protected and check mutex is held for lockdep enabled builds. Fixes: 212ed75dc5fb ("netfilter: nf_tables: integrate pipapo into commit protocol") Signed-off-by: Florian Westphal --- net/netfilter/nft_set_pipapo.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c index a5b8301afe4a..5fa12cfc7b84 100644 --- a/net/netfilter/nft_set_pipapo.c +++ b/net/netfilter/nft_set_pipapo.c @@ -1697,6 +1697,17 @@ static void nft_pipapo_commit(const struct nft_set *set) priv->clone = new_clone; } +static bool nft_pipapo_transaction_mutex_held(const struct nft_set *set) +{ +#ifdef CONFIG_PROVE_LOCKING + const struct net *net = read_pnet(&set->net); + + return lockdep_is_held(&nft_pernet(net)->commit_mutex); +#else + return true; +#endif +} + static void nft_pipapo_abort(const struct nft_set *set) { struct nft_pipapo *priv = nft_set_priv(set); @@ -1705,7 +1716,7 @@ static void nft_pipapo_abort(const struct nft_set *set) if (!priv->dirty) return; - m = rcu_dereference(priv->match); + m = rcu_dereference_protected(priv->match, nft_pipapo_transaction_mutex_held(set)); new_clone = pipapo_clone(m); if (IS_ERR(new_clone)) -- 2.41.0