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 B6BA4C433F5 for ; Wed, 9 Mar 2022 16:25:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234927AbiCIQ0O (ORCPT ); Wed, 9 Mar 2022 11:26:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238120AbiCIQVT (ORCPT ); Wed, 9 Mar 2022 11:21:19 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C64691520E1; Wed, 9 Mar 2022 08:18:56 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6377D615F1; Wed, 9 Mar 2022 16:18:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D015C340E8; Wed, 9 Mar 2022 16:18:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646842735; bh=yv24BEIQB2Wa9G21wq5trSJnLc3FQVzB/HOeXIspnWk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l19KADzZvjJH/kZ4pJpMw0pHtWPr6vwS0mk+NN3BHpzZiufSxCruRKbHWLnuFAqYi h22e4VVXv2gXjMALPHk2c6fZzB2NDJUys44OgUVHJIUs95HxQF66bhUjXiVt/8wqhB zqBxu0k4XrkK6uA67lUtODJZsi0BKhe7wmqSkPFwBrxVcP/YjFzBtimuaFe6UJJGKl QYqjAn8pzXiCxyPJl1apxPM2xRp1jjOxaBwST1utsTVQHZnnfYhb9j+aafDT+52PUw s+4rXYji73igRwBrfaWnXfkvISIGa6bwR1KfgunxMPGbjEXBZ3L3BI0kxBlRmWp5Ei BgVPktjXNI/9w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Florian Westphal , Eric Dumazet , Pablo Neira Ayuso , Sasha Levin , kadlec@netfilter.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org Subject: [PATCH AUTOSEL 5.16 18/27] netfilter: egress: silence egress hook lockdep splats Date: Wed, 9 Mar 2022 11:16:55 -0500 Message-Id: <20220309161711.135679-18-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220309161711.135679-1-sashal@kernel.org> References: <20220309161711.135679-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Florian Westphal [ Upstream commit 17a8f31bba7bac8cce4bd12bab50697da96e7710 ] 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 Signed-off-by: Sasha Levin --- 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; -- 2.34.1