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_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 CF9A3C433E0 for ; Thu, 28 May 2020 08:51:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A50C020B80 for ; Thu, 28 May 2020 08:51:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727976AbgE1Ivh (ORCPT ); Thu, 28 May 2020 04:51:37 -0400 Received: from smtp2.math.uni-bielefeld.de ([129.70.45.13]:55740 "EHLO smtp2.math.uni-bielefeld.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727088AbgE1Ivg (ORCPT ); Thu, 28 May 2020 04:51:36 -0400 Received: from math.uni-bielefeld.de (kvm01.math.uni-bielefeld.de [129.70.45.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by smtp2.math.uni-bielefeld.de (Postfix) with ESMTPSA id 9883F60236; Thu, 28 May 2020 10:51:34 +0200 (CEST) Date: Thu, 28 May 2020 10:51:33 +0200 From: Jean Rene Dawin To: Oliver Neukum Cc: linux-usb@vger.kernel.org Subject: Re: Kernel Oops in cdc_acm Message-ID: <20200528085133.GA17192@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> <1590569589.2838.50.camel@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1590569589.2838.50.camel@suse.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Oliver Neukum wrote on Wed 27/05/20 10:53: > 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? Hi, I tested 0afccd7601514c4b83d8cc58c740089cc447051d and couldn't get it to show the symptoms. Then I tested a4e7279cd1d19f48f0af2a10ed020febaa9ac092 with your patch applied and it still showed the symptom [ 730.590055] Call Trace: [ 730.590058] [ 730.590062] queue_work_on+0x36/0x40 [ 730.590065] __usb_hcd_giveback_urb+0x6f/0x120 [ 730.590067] usb_giveback_urb_bh+0xa6/0x100 [ 730.590070] tasklet_action_common.isra.0+0x5f/0x130 [ 730.590074] __do_softirq+0x111/0x34d [ 730.590077] irq_exit+0xac/0xd0 [ 730.590078] do_IRQ+0x89/0x140 [ 730.590080] common_interrupt+0xf/0xf but very non-deterministic. The first time the error came up after the battery was removed the second time. Then after the fourth time. And testing again this morning it was after six removals. I will try to narrow the conditions that tirgger the behaviour. It seems the timing is important. Regards, Jean Rene