From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752993AbdKTU6I (ORCPT ); Mon, 20 Nov 2017 15:58:08 -0500 Received: from mail-wm0-f68.google.com ([74.125.82.68]:38377 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752933AbdKTU6F (ORCPT ); Mon, 20 Nov 2017 15:58:05 -0500 X-Google-Smtp-Source: AGs4zMb19kX1H4f5wwFeDQkBjmur10Tx0RXRV/QOBVao9cK1S2auk2p9tFeKezEjSTdCCo56sx8WUA== Date: Mon, 20 Nov 2017 21:58:02 +0100 From: Luc Van Oostenryck To: Matthew Wilcox Cc: Tim Hansen , Al Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds , alexander.levin@one.verizon.com, "Paul E. McKenney" Subject: Re: [PATCH] fs: Safe rcu access to hlist. Message-ID: <20171120205801.dtqloltgfxkmfxee@ltop.local> References: <20171119200210.hhrklgm6hxhoyhqh@debian> <20171119212849.GV21978@ZenIV.linux.org.uk> <20171120185535.ggmnui2ud3ixqw7g@debian> <20171120200130.xhfj6zeczg3jfhcx@ltop.local> <20171120204253.GA8933@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171120204253.GA8933@bombadil.infradead.org> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 20, 2017 at 12:42:53PM -0800, Matthew Wilcox wrote: > > I disagree. The notion of whether a pointer is protected by RCU or not > is definitely not transient. Sure. But what about the memory it points to? It's just 'normal' kernel memory, there is nowhere something like some 'RCU memory', right? And the memory accessed through a __rcu annotated pointer can be legally be accessed with normal memory operation, because it's only the pointer that is concerned by the annotation? -- Luc