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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 4E816C433E0 for ; Wed, 27 May 2020 08:53:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 319032078B for ; Wed, 27 May 2020 08:53:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388314AbgE0IxO (ORCPT ); Wed, 27 May 2020 04:53:14 -0400 Received: from mx2.suse.de ([195.135.220.15]:57314 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388112AbgE0IxO (ORCPT ); Wed, 27 May 2020 04:53:14 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id F3B52AD65; Wed, 27 May 2020 08:53:15 +0000 (UTC) Message-ID: <1590569589.2838.50.camel@suse.com> Subject: Re: Kernel Oops in cdc_acm From: Oliver Neukum To: Jean Rene Dawin Cc: linux-usb@vger.kernel.org Date: Wed, 27 May 2020 10:53:09 +0200 In-Reply-To: <20200526195750.GA10336@math.uni-bielefeld.de> References: <20200525120026.GA11378@math.uni-bielefeld.de> <1590409690.2838.7.camel@suse.com> <20200525191624.GA28647@math.uni-bielefeld.de> <1590491586.2838.38.camel@suse.com> <20200526195750.GA10336@math.uni-bielefeld.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Am Dienstag, den 26.05.2020, 21:57 +0200 schrieb Jean Rene Dawin: > Oliver Neukum wrote on Tue 26/05/20 13:13: > > Hi, > > > > may I ask whether you did the test with removing the battery twice with > > an older kernel? Could you please go back to > > f6cc6093a729ede1ff5658b493237c42b82ba107 > > and repeat the test of a second battery removal with that state? > > I just cannot find anything pointing to a change that could cause > > this issue within that time. > > Hi, > > testing with f6cc6093a729ede1ff5658b493237c42b82ba107 looks like this: OK, we have two possibilities here. Either a4e7279cd1d19f48f0af2a10ed020febaa9ac092 or 0afccd7601514c4b83d8cc58c740089cc447051d have had a really wierd effect, or they introduced a bug that hid a later bug. Can I ask you to run a complicated test to decide between these possibilities? Could you test a4e7279cd1d19f48f0af2a10ed020febaa9ac092 together with the patch I sent you applied on top? > Interesting is, that at the second time, the usb disconnect message > conmes first, and then a message from cdc_acm acm_port_activate. Basically you are deliberately creating a race condition between error handling and disconnect. That is a feature of the HC design. Regards Oliver