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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 3C8FCC43215 for ; Fri, 29 Nov 2019 15:46:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1C32D2075C for ; Fri, 29 Nov 2019 15:46:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727126AbfK2PqS (ORCPT ); Fri, 29 Nov 2019 10:46:18 -0500 Received: from mx2.suse.de ([195.135.220.15]:43910 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726808AbfK2PqS (ORCPT ); Fri, 29 Nov 2019 10:46:18 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 4BF44B28F; Fri, 29 Nov 2019 15:46:16 +0000 (UTC) Subject: Re: [PATCH v2 1/2] xen/xenbus: reference count registered modules To: Paul Durrant , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org Cc: Jan Beulich , Boris Ostrovsky , Stefano Stabellini References: <20191129134306.2738-1-pdurrant@amazon.com> <20191129134306.2738-2-pdurrant@amazon.com> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: <82ff3fdf-b6f6-656d-4638-3b9f0a264fab@suse.com> Date: Fri, 29 Nov 2019 16:46:15 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: <20191129134306.2738-2-pdurrant@amazon.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29.11.19 14:43, Paul Durrant wrote: > To prevent a module being removed whilst attached to a frontend, and > hence xenbus calling into potentially invalid text, take a reference on > the module before calling the probe() method (dropping it if unsuccessful) > and drop the reference after returning from the remove() method. > > NOTE: This allows the ad-hoc reference counting in xen-netback to be > removed. This will be done in a subsequent patch. > > Suggested-by: Jan Beulich > Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross Juergen