From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941770AbcIHMEw (ORCPT ); Thu, 8 Sep 2016 08:04:52 -0400 Received: from x127155.tudelft.net ([131.180.127.155]:37580 "EHLO djo.tudelft.nl" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1030255AbcIHMEr (ORCPT ); Thu, 8 Sep 2016 08:04:47 -0400 X-Greylist: delayed 401 seconds by postgrey-1.27 at vger.kernel.org; Thu, 08 Sep 2016 08:04:47 EDT Date: Thu, 8 Sep 2016 13:58:03 +0200 From: Wim Osterholt To: oliver@neukum.org Cc: oneukum@suse.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Wim Osterholt Subject: crash by cdc_acm driver in kernels 4.8-rc1/5 Message-ID: <20160908115803.GA28274@djo.tudelft.nl> Reply-To: wim@djo.tudelft.nl MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org L.S. up to vanilla kernel 4.7.3 I've seen no problems. On two different dekstops running vanilla kernel-4.8 I can force a crash by inserting an USB-modem that requires module cdc_acm.ko . (Strangely enough that doesn't happen on my laptop.) The moment that cdc_acm loads (manually or automatically - the hardware needs to be present) a kernel oops occurs. The system remains responsive for a while, but a reboot is necessairy. If you try a neat shutdown, the system will hang forever after 'remounting fs read-only'. You'll need a power-down. The oops tells things that I didn't all write down, but it says null pointer dereference at 00000246 ... failed while handling devices/pci0000:00/0000:00:1d.3/usb7/7-1/7-1:1d etc. ... udevd .. is taking too long.. Could someone please explain and repair the magic that is happening here? Thanks in advance, Wim Osterholt. ----- wim@djo.tudelft.nl -----