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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94580C4CECD for ; Mon, 27 Apr 2020 18:20:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7400E20775 for ; Mon, 27 Apr 2020 18:20:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726567AbgD0SU5 (ORCPT ); Mon, 27 Apr 2020 14:20:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42312 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726228AbgD0SU5 (ORCPT ); Mon, 27 Apr 2020 14:20:57 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4524AC0610D5; Mon, 27 Apr 2020 11:20:57 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 14F2C15D54880; Mon, 27 Apr 2020 11:20:55 -0700 (PDT) Date: Mon, 27 Apr 2020 11:20:54 -0700 (PDT) Message-Id: <20200427.112054.486660514927430577.davem@davemloft.net> To: xiyuyang19@fudan.edu.cn Cc: andrew.hendry@gmail.com, kuba@kernel.org, tanxin.ctf@gmail.com, gregkh@linuxfoundation.org, allison@lohutok.net, tglx@linutronix.de, linux-x25@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, yuanxzhang@fudan.edu.cn, kjlu@umn.edu Subject: Re: [PATCH v2] net/x25: Fix x25_neigh refcnt leak when x25 disconnect From: David Miller In-Reply-To: <1587819994-40137-1-git-send-email-xiyuyang19@fudan.edu.cn> References: <1587819994-40137-1-git-send-email-xiyuyang19@fudan.edu.cn> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 27 Apr 2020 11:20:55 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xiyu Yang Date: Sat, 25 Apr 2020 21:06:25 +0800 > x25_connect() invokes x25_get_neigh(), which returns a reference of the > specified x25_neigh object to "x25->neighbour" with increased refcnt. > > When x25 connect success and returns, the reference still be hold by > "x25->neighbour", so the refcount should be decreased in > x25_disconnect() to keep refcount balanced. > > The reference counting issue happens in x25_disconnect(), which forgets > to decrease the refcnt increased by x25_get_neigh() in x25_connect(), > causing a refcnt leak. > > Fix this issue by calling x25_neigh_put() before x25_disconnect() > returns. > > Signed-off-by: Xiyu Yang > Signed-off-by: Xin Tan Applied.