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=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 7277CC43463 for ; Fri, 18 Sep 2020 14:52:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28C1B21973 for ; Fri, 18 Sep 2020 14:52:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726839AbgIROwc (ORCPT ); Fri, 18 Sep 2020 10:52:32 -0400 Received: from netrider.rowland.org ([192.131.102.5]:51789 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1726253AbgIROwc (ORCPT ); Fri, 18 Sep 2020 10:52:32 -0400 Received: (qmail 1130178 invoked by uid 1000); 18 Sep 2020 10:52:31 -0400 Date: Fri, 18 Sep 2020 10:52:31 -0400 From: Alan Stern To: "M. Vefa Bicakci" Cc: linux-usb@vger.kernel.org, Andrey Konovalov , stable@vger.kernel.org, Greg Kroah-Hartman , Bastien Nocera , syzkaller@googlegroups.com, Shuah Khan Subject: Re: [PATCH 1/3] usbcore/driver: Fix specific driver selection Message-ID: <20200918145231.GA1130146@rowland.harvard.edu> References: <20200917144151.355848-1-m.v.b@runbox.com> <363eab9a-c32a-4c60-4d6b-14ae8d873c52@runbox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <363eab9a-c32a-4c60-4d6b-14ae8d873c52@runbox.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Fri, Sep 18, 2020 at 05:31:26PM +0300, M. Vefa Bicakci wrote: > Hello all, > > I noticed that applying this patch on its own to the kernel causes the following > unexpected behaviour: As soon as the usbip_host module is loaded, all of the > USB devices are re-probed() by their drivers, and this causes the USB devices > connected to my system to be momentarily unavailable. This happens because > *without* the third patch in this patch set, the match function for the usbip_host > device driver unconditionally returns true. > > The third patch in this patch set [1] makes this unexpected behaviour go > away, as it makes the usbip device driver's match function only match devices > that were requested by user-space to be used with USB-IP. > > Is this something to be concerned about? I was thinking of people who might be > using git-bisect, who might encounter this issue in an unexpected manner. > > As a potential solution, I can prepare another patch to revert commit > 7a2f2974f2 ("usbip: Implement a match function to fix usbip") so that this > unexpected behaviour will not be observed. This revert would be placed as > the first patch in the patch series. Yes, that sounds like a good solution. Alan Stern