From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753735Ab1KAP7x (ORCPT ); Tue, 1 Nov 2011 11:59:53 -0400 Received: from mail-gy0-f174.google.com ([209.85.160.174]:46435 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751911Ab1KAP7w (ORCPT ); Tue, 1 Nov 2011 11:59:52 -0400 Date: Tue, 1 Nov 2011 08:59:45 -0700 From: Tejun Heo To: Oleg Nesterov Cc: trisha yad , linux-mm , Russell King - ARM Linux , linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, kamezawa.hiroyu@jp.fujitsu.com, mhocko@suse.cz, rientjes@google.com, Andrew Morton , Konstantin Khlebnikov , KOSAKI Motohiro , "Rafael J. Wysocki" , Rusty Russell Subject: Re: Issue with core dump Message-ID: <20111101155945.GQ18855@google.com> References: <20111101152320.GA30466@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111101152320.GA30466@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, Nov 01, 2011 at 04:23:20PM +0100, Oleg Nesterov wrote: > Whatever we do, we can't "stop" other threads at the time when > thread 'a' traps. All we can do is to try to shrink the window. Yeah, "at the time" can't even be defined preciesly. Order of operation isn't clearly defined in absence of synchronization constructs. In the described example, there's unspecified amount of time (or cycles rather) between the load of the global variable and the thread faulting. Anything could have happened inbetween no matter how immediate core dump was. As long as we're reasonably immediate, which I think we already are, I don't think there's much which needs to be changed. Thanks. -- tejun