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 00E71C3DA78 for ; Tue, 17 Jan 2023 11:01:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236429AbjAQLBk (ORCPT ); Tue, 17 Jan 2023 06:01:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236400AbjAQLBf (ORCPT ); Tue, 17 Jan 2023 06:01:35 -0500 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C559D2331D for ; Tue, 17 Jan 2023 03:01:34 -0800 (PST) Received: by mail-qk1-x749.google.com with SMTP id j10-20020a05620a288a00b0070630ecfd9bso7271264qkp.20 for ; Tue, 17 Jan 2023 03:01:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=zgDOisqQY4khTeREa4/mVeCS308Srl2wAqZ7Yctk2nw=; b=tQ4HMt/wknqmDPJcWGElO2jhZ2cPr6FKU1fCWYoal7Q1mfM8YzW4UK4qrMUpGH4Tpi SiuUVtTgTgEo8jAvsyeU4ffTF/f68Jmpp6It5C6Bz+N6WeSpCUL3QG/ObyEPIAZAtqjI h0UUd9etTFP4V2Unk2D9hUbrPnycCJdPImpa/k9K/ykmjB3HrInqrQOEub4hNPaYDuG2 75WrofG3Br6lEaXDfiWMx1j4rULwUaf9r8vVfBKgXq8ZROjlY/+mW4DgPwZGBk1Ii8Ky gBHqrqHkS7xfEB0MKYCNsDDPxvYi/OKXFxj7fNg5WJqEl4ykQssQFbflVDp1YI93HUbU BZxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=zgDOisqQY4khTeREa4/mVeCS308Srl2wAqZ7Yctk2nw=; b=rdbagtVo0r7illkWjcCVHQktcO4AW0ObKGnDljBkHPGSostcfSEaK4j9NWn4b85HsS bGB5ktoGdqTff6c3rRzAR8Y84Lj7Wt30kIinnON6WOSkPvUkg3f3i6D8nB9OsXZyiODm pT5wR3JD1FGe9Hcntj9JP+BaTO8Ihfm7dkdS16PGNMnuF1sQ9ogBfj8wYfgH2LehIkup /IUgef89ONCj4zeBHQS5e9OnB7w4G+hcIM/YHwqVUPStbnGx/DjCkxRTbVw3IHOli+eR otgGSeXK3FhPGoPihdutFwUpw7K0tDtaR0cVtXJO6aJsXZ1u6U5OEaXbQUbfRQZhDLn3 xCjQ== X-Gm-Message-State: AFqh2kruWM/J9OsCQ7xEkR9Dbobh6PDTaq8xxqG1pdzEEJcospvLyV+S wjki68fIvkkOHu1L37GKUl+CntP6w/y4EQ== X-Google-Smtp-Source: AMrXdXtBWu8kd7H4hqO4taf1D0FZC1lGB2NDRl3QM7nMguJBy4gK6fO/50IfigPHy8Oc++Vwf79aNXyucXUZZg== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:395a]) (user=edumazet job=sendgmr) by 2002:a05:622a:4015:b0:3b6:3b2c:698b with SMTP id cf21-20020a05622a401500b003b63b2c698bmr129471qtb.29.1673953293970; Tue, 17 Jan 2023 03:01:33 -0800 (PST) Date: Tue, 17 Jan 2023 11:01:31 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Message-ID: <20230117110131.1362738-1-edumazet@google.com> Subject: [PATCH net] l2tp: prevent lockdep issue in l2tp_tunnel_register() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet , syzbot+bbd35b345c7cab0d9a08@syzkaller.appspotmail.com, Cong Wang , Guillaume Nault Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 --- 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 b6554e32bb12ae7813cc06c01e4d1380af667375..03608d3ded4b83d1e59e064e482f54cffcdf5240 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1483,10 +1483,8 @@ 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); @@ -1523,6 +1521,7 @@ 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); -- 2.39.0.314.g84b9a713c41-goog