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 682DCC433FE for ; Thu, 17 Mar 2022 12:53:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234150AbiCQMzM (ORCPT ); Thu, 17 Mar 2022 08:55:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235016AbiCQMyX (ORCPT ); Thu, 17 Mar 2022 08:54:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B94FB1EC6D; Thu, 17 Mar 2022 05:53:07 -0700 (PDT) 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 57B1E61578; Thu, 17 Mar 2022 12:53:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34AE9C340E9; Thu, 17 Mar 2022 12:53:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1647521586; bh=yv24BEIQB2Wa9G21wq5trSJnLc3FQVzB/HOeXIspnWk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GCWssIRfFt7sPSBBx3n8wRbQtkSr84RgCLDw1ijymaxg6AxsVAurp9TYLoczn29bS DhAwupciTm+SxqJp3yK9llc5pvSM61TFNkS80HLyUGg2BhANZV5DwrB1tg7LevIOeu itNTrQLjOfDSItVkL3buf/D4bc1Xng3ijuuRH8js= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Florian Westphal , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 5.16 18/28] netfilter: egress: silence egress hook lockdep splats Date: Thu, 17 Mar 2022 13:46:09 +0100 Message-Id: <20220317124527.285482124@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220317124526.768423926@linuxfoundation.org> References: <20220317124526.768423926@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@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