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 36286C433FE for ; Tue, 1 Mar 2022 21:53:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238503AbiCAVy2 (ORCPT ); Tue, 1 Mar 2022 16:54:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230144AbiCAVy0 (ORCPT ); Tue, 1 Mar 2022 16:54:26 -0500 Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 57F5F61A13; Tue, 1 Mar 2022 13:53:45 -0800 (PST) Received: from localhost.localdomain (unknown [78.30.32.163]) by mail.netfilter.org (Postfix) with ESMTPSA id 8AD3F608F7; Tue, 1 Mar 2022 22:52:16 +0100 (CET) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org Subject: [PATCH net 3/8] netfilter: egress: silence egress hook lockdep splats Date: Tue, 1 Mar 2022 22:53:32 +0100 Message-Id: <20220301215337.378405-4-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220301215337.378405-1-pablo@netfilter.org> References: <20220301215337.378405-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Florian Westphal Netfilter assumes its called with rcu_read_lock held, but in egress hook case it may be called with BH readlock. This triggers lockdep splat. In order to avoid to change all rcu_dereference() to rcu_dereference_check(..., rcu_read_lock_bh_held()), wrap nf_hook_slow with read lock/unlock pair. Reported-by: Eric Dumazet Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter_netdev.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/netfilter_netdev.h b/include/linux/netfilter_netdev.h index b4dd96e4dc8d..e6487a691136 100644 --- a/include/linux/netfilter_netdev.h +++ b/include/linux/netfilter_netdev.h @@ -101,7 +101,11 @@ static inline struct sk_buff *nf_hook_egress(struct sk_buff *skb, int *rc, nf_hook_state_init(&state, NF_NETDEV_EGRESS, NFPROTO_NETDEV, dev, NULL, NULL, dev_net(dev), NULL); + + /* nf assumes rcu_read_lock, not just read_lock_bh */ + rcu_read_lock(); ret = nf_hook_slow(skb, &state, e, 0); + rcu_read_unlock(); if (ret == 1) { return skb; -- 2.30.2