From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932222Ab1CVPuT (ORCPT ); Tue, 22 Mar 2011 11:50:19 -0400 Received: from smtpbg52.qq.com ([64.71.138.43]:36453 "HELO smtpbg52.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932096Ab1CVPuO (ORCPT ); Tue, 22 Mar 2011 11:50:14 -0400 X-QQ-mid: esmtp3t1300808894t338t15176 X-QQ-SSF: 00000000000000F0FF300F000000000 Date: Tue, 22 Mar 2011 23:48:16 +0800 From: "Lina Lu" To: "Vivek Goyal" Cc: "linux kernel mailing list" References: <201103201523220468314@foxmail.com>, <201103222332465003523@foxmail.com> Subject: Re: Re: Re: cfq-iosched.c: panic in cfq_dispatch_requests Message-ID: <201103222348152343383@foxmail.com> X-mailer: Foxmail 6, 15, 201, 23 [cn] Mime-Version: 1.0 Content-Type: text/plain; charset="gb2312" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011-03-22 23:39:48, Vivek Goyal wrote: >On Tue, Mar 22, 2011 at 11:32:47PM +0800, Lina Lu wrote: >> On 2011-03-21 22:08:19, Vivek Goyal wrote: >> >On Sun, Mar 20, 2011 at 03:23:23PM +0800, Lina Lu wrote: >> >> Hi Vivek, >> >> >> >> I did some test with blkio weight policy these days. The kernel panic >> >> once in a while. >> >> >> >> From the calltrace, It 's in func cfq_dispatch_requests(+0x058D). >> >> And I caught a divide by zero error with system monitor tools. >> > >> >Hi Lina, >> > >> >Can you please paste the full backtrace here. >> > >> >> >> >> The panic happens when I first set 100 weight to two IO pids, then >> >> change the weight to 200, and begin to perform IO. The kernel panic >> >> accurately when the IO begin. >> > >> >So you notice this only if weights are changed otherwise not? >> >> Hi Vivek >> >> Thanks for this patch! I did objdump and find place that divide by zero. >> It's in cfq_group_slice function, the st->total_weight is zero in my issue. >> As described in the patch, this is because I change the weight when the >> group on service tree. > >Ok, so this patch did solve the issue you are facing? > Yes, this patch did solve the issue. And I will do more test these days, if there is any other problem, I will keep you know. Thanks Lina