From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752659AbcGVFm2 (ORCPT ); Fri, 22 Jul 2016 01:42:28 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:32912 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751020AbcGVFm0 (ORCPT ); Fri, 22 Jul 2016 01:42:26 -0400 To: LKML , viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org From: Chris Clayton Subject: 4.7.0-rc7+: Oops during boot with USB pen drive inserted Message-ID: Date: Fri, 22 Jul 2016 06:41:40 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, With Linus' latest and greatest, I get an opps when I boot my laptop with a pen drive inserted in any USB port. The oops message is: Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,2) The oops seems to be 100% repeatable. If a USB pen drive is not inserted, the laptop boots successfully. I've taken a photograph of the oops and you can view it at http://s714.photobucket.com/user/chris2553/media/IMG_20160722_053841.jpg.html. At the top of the picture, I notice that the partitions on my actual boot disk are being reported as being on /dev/sdb, so it seems likely that, at this point, the pen drive is being seen as /dev/sda, although that has scrolled off the screen. I don't boot via a ramdisk - my kernel has ext4 built in. The grub2 entry is: menuentry "Krisux, Linux 4.7.0-rc7+" { insmod ext2 set root=(hd0,2) linux /boot/vmlinuz-4.7.0-rc7+ ro root=/dev/sda2 resume=/dev/sda6 rootfstype=ext4 net.ifnames=0 } (BTW, Krisux is not a real distro - it's just the name I have given Linux from Scratch system.) The stack that is dumped is: dump_stack panic printk mount_block_root prepare_namespace kernel_init_freeable kernel_init ret_from_fork rest_init I realise I could work around this by specifying the boot partition by, say, its UUID, but I thought you would want me to report this anyway. Of course, I'm happy to provide any other information required and to test any fix, but I will be out and about for the next 14-16 hours, so it will be later tonight or maybe even tomorrow before I can respond. Chris