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 DA5AFC636CB for ; Mon, 30 Jan 2023 14:14:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237288AbjA3OOa (ORCPT ); Mon, 30 Jan 2023 09:14:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237267AbjA3OO3 (ORCPT ); Mon, 30 Jan 2023 09:14:29 -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 5734B1BAEC for ; Mon, 30 Jan 2023 06:14:27 -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 DD5AB6102E for ; Mon, 30 Jan 2023 14:14:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EED1CC433D2; Mon, 30 Jan 2023 14:14:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675088066; bh=ffzel8X/qV7MnDhW26+rmNDsh9ooM5L26oNnOs9qV/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xNONLbgDfPoGsADhm0x8/UcNnOzVzOUl2Ee91X0H0+7y43NcRI6IWnlYEeV7URsly dl1eVWpx556EuwQJqUfxrMYVapE4ul8aCGEn0q/GG2K0Z559/Qa6W7/r1bJ7N5vw1o 1yKV53FkXxT+oySNELq8jvQIOMvl0HPMbfioceQ8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+bbd35b345c7cab0d9a08@syzkaller.appspotmail.com, Eric Dumazet , Cong Wang , Guillaume Nault , "David S. Miller" , Sasha Levin Subject: [PATCH 5.15 073/204] l2tp: prevent lockdep issue in l2tp_tunnel_register() Date: Mon, 30 Jan 2023 14:50:38 +0100 Message-Id: <20230130134319.545869747@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134316.327556078@linuxfoundation.org> References: <20230130134316.327556078@linuxfoundation.org> User-Agent: quilt/0.67 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: Eric Dumazet [ Upstream commit b9fb10d131b8c84af9bb14e2078d5c63600c7dea ] lockdep complains with the following lock/unlock sequence: lock_sock(sk); write_lock_bh(&sk->sk_callback_lock); [1] release_sock(sk); [2] write_unlock_bh(&sk->sk_callback_lock); We need to swap [1] and [2] to fix this issue. Fixes: 0b2c59720e65 ("l2tp: close all race conditions in l2tp_tunnel_register()") Reported-by: syzbot+bbd35b345c7cab0d9a08@syzkaller.appspotmail.com Signed-off-by: Eric Dumazet Link: https://lore.kernel.org/netdev/20230114030137.672706-1-xiyou.wangcong@gmail.com/T/#m1164ff20628671b0f326a24cb106ab3239c70ce3 Cc: Cong Wang Cc: Guillaume Nault Reviewed-by: Guillaume Nault Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/l2tp/l2tp_core.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 4c5227048be4..a2b13e213e06 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1485,10 +1485,8 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, lock_sock(sk); write_lock_bh(&sk->sk_callback_lock); ret = l2tp_validate_socket(sk, net, tunnel->encap); - if (ret < 0) { - release_sock(sk); + if (ret < 0) goto err_inval_sock; - } rcu_assign_sk_user_data(sk, tunnel); write_unlock_bh(&sk->sk_callback_lock); @@ -1525,6 +1523,7 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net, err_inval_sock: write_unlock_bh(&sk->sk_callback_lock); + release_sock(sk); if (tunnel->fd < 0) sock_release(sock); -- 2.39.0