From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754652AbbFWLJD (ORCPT ); Tue, 23 Jun 2015 07:09:03 -0400 Received: from mail.skyhub.de ([78.46.96.112]:41705 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753371AbbFWLIz (ORCPT ); Tue, 23 Jun 2015 07:08:55 -0400 Date: Tue, 23 Jun 2015 13:08:44 +0200 From: Borislav Petkov To: Ingo Molnar Cc: Andy Lutomirski , Kees Cook , "Paul E. McKenney" , "linux-kernel@vger.kernel.org" , Oleg Nesterov , Denys Vlasenko , Brian Gerst , =?utf-8?B?RnLDqWTDqXJpYw==?= Weisbecker , X86 ML , Rik van Riel Subject: Re: [PATCH v2 03/14] notifiers: Assert that RCU is watching in notify_die Message-ID: <20150623110844.GG24268@pd.tnic> References: <20150622113649.GB20244@pd.tnic> <20150622163333.GC20244@pd.tnic> <20150623085624.GA2882@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20150623085624.GA2882@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 23, 2015 at 10:56:24AM +0200, Ingo Molnar wrote: > So I think the theory is that crashes do happen, and that any RCU warning only > matters to (usually) small race windows. > > So by the time a difficult crash truly happens, exactly in that race window, we'd > have fixed the RCU warning long ago. > > I.e. the placement of the RCU warning isn't really relevant in the long run, as it > should not trigger. > > In the short run it's probably more important to have it first, because if we have > that RCU race then we don't know whether we can trust anything that happens after > executing the (flawed) notifier chain. > > Does that logic make sense to you? Yap, it does actually. Nice :) Thanks! -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --