Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755653Ab3C1Cvr (ORCPT ); Wed, 27 Mar 2013 22:51:47 -0400 Received: from mail-pa0-f49.google.com ([209.85.220.49]:54138 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755079Ab3C1Cvq (ORCPT ); Wed, 27 Mar 2013 22:51:46 -0400 Message-ID: <5153B03E.2050201@gmail.com> Date: Wed, 27 Mar 2013 19:51:42 -0700 From: Dirk Brandewie User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Parag Warudkar CC: rjw@sisk.pl, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, dirk.brandewie@gmail.com Subject: Re: intel_pstate_timer_func divide by zero oops References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1476 Lines: 45 Is there any way to capture the beginning of this trace? pid_param_set() is on the stack which means that something is changing the debugfs parameters or the stack is FUBAR. On 03/27/2013 06:49 PM, Parag Warudkar wrote: > I get this same oops occassionally - the machine freezes and there doesn't > seem to be any record of the oops on disk. > > > That is - > sample->pstate_pct_busy = 100 - div64_u64( > sample->idletime_us * 100, > sample->duration_us); > I don't see how duration_us can be zero unless somehow I am getting back-to-back timer callbacks which seems unlikely since the timer is not re-armed until the timer function is about to return and the driver has done all its work for the sample period --Dirk > So looks like sample->duration_us is 0? If so, that implies that > ktime_us_delta(now, cpu->prev_sample) is zero. I am not entirely sure how > to handle this case - return if sampling too early, or if there is some > other bug making the delta calculation go poof. > > > Thanks, > > Parag > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/