From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752680Ab2LTTSW (ORCPT ); Thu, 20 Dec 2012 14:18:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:5239 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752416Ab2LTTSF (ORCPT ); Thu, 20 Dec 2012 14:18:05 -0500 Date: Thu, 20 Dec 2012 14:17:53 -0500 From: Don Zickus To: =?iso-8859-1?Q?Bj=F8rn?= Mork Cc: Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, Norbert Warmuth , Joseph Salisbury , Thomas Gleixner Subject: Re: [RESEND][PATCH v3] watchdog: Fix disable/enable regression Message-ID: <20121220191752.GR88797@redhat.com> References: <87y5h1c70y.fsf@nemi.mork.no> <1355946691-7969-1-git-send-email-bjorn@mork.no> <20121219201336.GK88797@redhat.com> <874njh7nd5.fsf@nemi.mork.no> <87zk1967jn.fsf@nemi.mork.no> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87zk1967jn.fsf@nemi.mork.no> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 19, 2012 at 10:44:44PM +0100, Bjørn Mork wrote: > Bjørn Mork writes: > > Don Zickus writes: > > > >> What about the opposite cases? > >> nmi_watchdog=1 > >> echo 1 > /sys/devices/system/cpu/cpu1/online > > > > I don't see why not. But verifying it would be nice. I thought that it > > would be a simple thing to test using qemu-kvm, but it seems that the > > CPU hotplugging support there isn't quite ready. The guest just dies > > with "Assertion `bus->allow_hotplug' failed." > > > > I'll go digging for alternatives, but if anyone else could verify this > > then I'd appreciate it. > > I just realized that you might not really want/need hotplugging, but > just booting with some cores initially offline? Actually, I did a poor job explaining myself but your previous email answered my question. The original problem was that hrtimer_cancel was being called on an un-initialized object. I was wondering what happens if watchdog_enable was called multiple times, would it re-initialize a new object causing a memory leak? But as you pointed out that couldn't happen. So I am fine with your changes. Thanks for the initial and follow up testing. Acked-by: Don Zickus