From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751649AbeDGCGo (ORCPT ); Fri, 6 Apr 2018 22:06:44 -0400 Received: from esa5.hgst.iphmx.com ([216.71.153.144]:48380 "EHLO esa5.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750807AbeDGCGm (ORCPT ); Fri, 6 Apr 2018 22:06:42 -0400 X-IronPort-AV: E=Sophos;i="5.48,417,1517846400"; d="scan'208";a="75443712" From: Bart Van Assche To: "wakko@animx.eu.org" CC: "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "richard.weinberger@gmail.com" , "linux-block@vger.kernel.org" Subject: Re: 4.15.14 crash with iscsi target and dvd Thread-Topic: 4.15.14 crash with iscsi target and dvd Thread-Index: AQHTyTSBb5uvLpZh0kGvcKoLkXFdJKPq6GkAgABbqICAAIUdgIAAU3eAgAAfGYCAAw0ygIADtuOAgAAFnoCAAAO2AIABfPAAgAARnwA= Date: Sat, 7 Apr 2018 02:06:39 +0000 Message-ID: References: <20180331221252.GA25573@animx.eu.org> <20180401113721.GA8471@animx.eu.org> <20180401163604.GB25011@animx.eu.org> <20180401182723.GA31755@animx.eu.org> <595a10cfb387e6b2ab4d2053b84fed9b3da9e079.camel@wdc.com> <20180406014644.GA16112@animx.eu.org> <20180406020651.GB16112@animx.eu.org> <20180407010334.GA11092@animx.eu.org> In-Reply-To: <20180407010334.GA11092@animx.eu.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=Bart.VanAssche@wdc.com; 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x-microsoft-antispam-message-info: +knNDGA6NSSkri/FRHBu3WQ6eGwv5S0DPzJlo4FlA0B7mDlzelirchugGu8h0pwbkw1eWed0xfoL9ZOPvQ4FfJh1QJ9hlmN2Jea2+qM/ZWh/RWp3PWHLQjA+EOIvyJCKFq/MIEJk/UKAavlzI98tI7XffwvLjMjrGZgQoZXb5TL8mpv+AD5luONgy/AYdS+VNYOu39E7/HMpQTyKFg8lm7m6MdFIYCDBvoaB8gw2gwuYaxIg420ILQT5I1AYVKvTjtjYTbpjk/Qv+NpwSQ6e2kCx4dT91mgJCOyIFu2UbjcAoz5VOLLXKLDlouJMjMlb0cvuVZaAF4nkqnXM41jdS6oLgrqUT3G9AEomIxt7VEG8NY1L5KhDDVQOIhMPvJtUR3Syp68BL77cgf73BbCiXHr4SLJ6WdmagtbTiRxauIU= spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="utf-8" Content-ID: <1273440D4C884042A0676C85A025C9AE@namprd04.prod.outlook.com> MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: 1fbf9918-1255-44b0-983c-08d59c2c333c X-MS-Exchange-CrossTenant-originalarrivaltime: 07 Apr 2018 02:06:39.3021 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR04MB0751 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id w3726wNo019080 On Fri, 2018-04-06 at 21:03 -0400, Wakko Warner wrote: > Bart Van Assche wrote: > > On Thu, 2018-04-05 at 22:06 -0400, Wakko Warner wrote: > > > I know now why scsi_print_command isn't doing anything. cmd->cmnd is null. > > > I added a dev_printk in scsi_print_command where the 2 if statements return. > > > Logs: > > > [ 29.866415] sr 3:0:0:0: cmd->cmnd is NULL > > > > That's something that should never happen. As one can see in > > scsi_setup_scsi_cmnd() and scsi_setup_fs_cmnd() both functions initialize > > that pointer. Since I have not yet been able to reproduce myself what you > > reported, would it be possible for you to bisect this issue? You will need > > to follow something like the following procedure (see also > > https://git-scm.com/docs/git-bisect): > > > > git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > git bisect start > > git bisect bad v4.10 > > git bisect good v4.9 > > > > and then build the kernel, install it, boot the kernel and test it. > > Depending on the result, run either git bisect bad or git bisect good and > > keep going until git bisect comes to a conclusion. This can take an hour or > > more. > > I have 1 question. Should make clean be done between tests? My box > compiles the whole kernel in 2 minutes. If you trust that the build system will figure out all dependencies then running make clean is not necessary. Personally I always run make clean during a bisect before rebuilding the kernel because if a header file has changed in e.g. the block layer a huge number of files has to be rebuilt anyway. Bart.