From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dirk Brandewie Subject: Re: intel_pstate_timer_func divide by zero oops Date: Wed, 27 Mar 2013 19:51:42 -0700 Message-ID: <5153B03E.2050201@gmail.com> References: Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:message-id:date:from:user-agent:mime-version:to:cc :subject:references:in-reply-to:content-type :content-transfer-encoding; bh=EfNbXf9+EzAFvBIhdP/nCyE8EcIuujVS6BBNmhf/3x8=; b=UDMKuyQHMZYFsS7cNAdQomHpsPj7/9aNo8wC3YnskBkjYEyZhizB13d5qA4+JYjNry Mwb+FRmENkYv8imsY/mnND3n/k1HBsghzAZWYjM7QHyZdkuVjXkDEWkNb4ExdpzC3B7Y NrQeiouSgKrApRIg3EspEXetdLzjd3OGfkPBk+9153nJYEz+/dN2HGcbjjfPM4Aovvrk L6KpJTUn6oLMElP9vVwMFgujrfZqP5vLQKC0DIYgUDjmxmtLvnSM3TQFVZUrubXauhBo i0fdHUHrrgK6uX3nXut2lgMrPedXWW6K4vqct9aQqE0Od/IiEYx2XnRfNrAwJX4QrJcn 2sbw== In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" 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 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 >