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 18C99C433E0 for ; Mon, 15 Jun 2020 20:20:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA3F0207D3 for ; Mon, 15 Jun 2020 20:20:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731445AbgFOUUd (ORCPT ); Mon, 15 Jun 2020 16:20:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731249AbgFOUUd (ORCPT ); Mon, 15 Jun 2020 16:20:33 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D1C2C061A0E; Mon, 15 Jun 2020 13:20:32 -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 0CC09120ED49A; Mon, 15 Jun 2020 13:20:32 -0700 (PDT) Date: Mon, 15 Jun 2020 13:20:31 -0700 (PDT) Message-Id: <20200615.132031.260816488025362367.davem@davemloft.net> To: bruceshenzk@gmail.com Cc: jcliburn@gmail.com, chris.snook@gmail.com, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] net: alx: fix race condition in alx_remove From: David Miller In-Reply-To: <20200615155029.21002-1-bruceshenzk@gmail.com> References: <20200614165912.25622-1-bruceshenzk@gmail.com> <20200615155029.21002-1-bruceshenzk@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.3 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, 15 Jun 2020 13:20:32 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zekun Shen Date: Mon, 15 Jun 2020 11:50:29 -0400 > There is a race condition exist during termination. The path is > alx_stop and then alx_remove. An alx_schedule_link_check could be called > before alx_stop by interrupt handler and invoke alx_link_check later. > Alx_stop frees the napis, and alx_remove cancels any pending works. > If any of the work is scheduled before termination and invoked before > alx_remove, a null-ptr-deref occurs because both expect alx->napis[i]. > > This patch fix the race condition by moving cancel_work_sync functions > before alx_free_napis inside alx_stop. Because interrupt handler can call > alx_schedule_link_check again, alx_free_irq is moved before > cancel_work_sync calls too. > > Signed-off-by: Zekun Shen Applied, thank you.