From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754447AbXDTLBd (ORCPT ); Fri, 20 Apr 2007 07:01:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992478AbXDTLBd (ORCPT ); Fri, 20 Apr 2007 07:01:33 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:40371 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754447AbXDTLBc (ORCPT ); Fri, 20 Apr 2007 07:01:32 -0400 Date: Fri, 20 Apr 2007 21:01:19 +1000 From: David Chinner To: Jarek Poplawski Cc: David Chinner , linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: [PATCH -mm] workqueue: debug possible endless loop in cancel_rearming_delayed_work Message-ID: <20070420110119.GS32602149@melbourne.sgi.com> References: <20070419065404.GB1782@ff.dom.local> <20070419144618.GG32602149@melbourne.sgi.com> <20070420081325.GB1695@ff.dom.local> <20070420085354.GP32602149@melbourne.sgi.com> <20070420102157.GD1695@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070420102157.GD1695@ff.dom.local> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 20, 2007 at 12:21:57PM +0200, Jarek Poplawski wrote: > On Fri, Apr 20, 2007 at 06:53:54PM +1000, David Chinner wrote: > ... > > Yes, after spending another two hours working out why my fix was > > then hanging in cancel_rearming_delayed_work() I was a little bit > > annoyed at the now obviously misleading comment. Five minutes later > > I agree with your feelings, but strictly speaking it's not "obviously > misleading": > > " * cancel_rearming_delayed_work - reliably kill off a delayed > keventd work whose handler rearms the delayed work." " This is not reliable if the handler rearms itself conditionally and it is restarted by external means." > And all your rearmed works were, probably, reliably killed! Yeah, it's the ones that weren't that we the problem ;) > > I'd fixed the bug properly. A better comment would have saved me two > > hours of wasted time..... > > It seems to be an Achilles' heel of linux... Too true.... Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group