From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752170Ab1C2JuW (ORCPT ); Tue, 29 Mar 2011 05:50:22 -0400 Received: from 0122700014.0.fullrate.dk ([95.166.99.235]:42432 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751388Ab1C2JuV (ORCPT ); Tue, 29 Mar 2011 05:50:21 -0400 Message-ID: <4D91AB5C.8030203@kernel.dk> Date: Tue, 29 Mar 2011 11:50:20 +0200 From: Jens Axboe MIME-Version: 1.0 To: Gui Jianfeng CC: Vivek Goyal , lkml Subject: Re: Bug at for-2.6.39/core References: <4D91AAB9.2000800@cn.fujitsu.com> In-Reply-To: <4D91AAB9.2000800@cn.fujitsu.com> 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 On 2011-03-29 11:47, Gui Jianfeng wrote: > Hi Jens, > > I trigger an OOPS when testing, the following script can reproduce > this bug on my box. > > #!/bin/sh > > mkdir /mnt/blkio > mount -t cgroup -o blkio blkio /mnt/blkio/ > mkdir /mnt/blkio/test1 /mnt/blkio/test2 > echo noop > /sys/block/sdb/queue/scheduler > dd iflag=direct if=/dev/sdb of=/dev/null bs=4k & > echo $! > /mnt/blkio/test1/tasks > dd iflag=direct if=/dev/sdb of=/dev/null bs=4k & > echo $! > /mnt/blkio/test2/tasks > sleep 3 > echo cfq > /sys/block/sdb/queue/scheduler > > ---- > eBUG: unable to handle kernel NULL pointer dereference at 0000000000000008 > IP: [] cfq_completed_request+0x38/0x7f0 This is a known bug, update to Linus' current -git and it's fixed. -- Jens Axboe