From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933078AbcI1PXn (ORCPT ); Wed, 28 Sep 2016 11:23:43 -0400 Received: from mx2.suse.de ([195.135.220.15]:60373 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932532AbcI1PXg (ORCPT ); Wed, 28 Sep 2016 11:23:36 -0400 Message-ID: <1475076210.4635.18.camel@suse.com> Subject: Re: crash by cdc_acm driver in kernels 4.8-rc1/5 From: Oliver Neukum To: wim@djo.tudelft.nl Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Date: Wed, 28 Sep 2016 17:23:30 +0200 In-Reply-To: <20160928150856.GA1424@djo.tudelft.nl> References: <20160908125850.GC28274@djo.tudelft.nl> <1473339915.32073.3.camel@suse.com> <20160912024340.GA16266@djo.tudelft.nl> <1474376714.4358.28.camel@suse.com> <20160920154520.GA12174@djo.tudelft.nl> <1474460477.2675.19.camel@suse.com> <20160921164122.GB18823@djo.tudelft.nl> <1474555250.30534.1.camel@suse.com> <20160927163414.GA21487@djo.tudelft.nl> <1475054164.4635.7.camel@suse.com> <20160928150856.GA1424@djo.tudelft.nl> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.11 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2016-09-28 at 17:08 +0200, Wim Osterholt wrote: > On Wed, Sep 28, 2016 at 11:16:04AM +0200, Oliver Neukum wrote: > > this should show you where it crashes. In addition I've attached > > a patch with paranoid debugging. Could you compile and test a kernel > > with it? > > > > Regards > > Oliver > > If you mean > echo "module cdc_acm +mpf" > /sys/kernel/debug/dynamic_debug/control > etc, then it will take some time because I don't have the cabling not > available now for a serial dump. > > Just 4.8-rc8 with the patched modules gave an oops of less than one screen > while the machine stayed responsive long enough to grab it with the mouse > and put it in a file: > > HP src # sync > HP src # [ 3744.914184] BUG: unable to handle kernel NULL pointer dereference at 00000249 The last view lines before that please with the debugging level ramped up to 9 please. Regards Oliver