Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933716Ab0KQKoT (ORCPT ); Wed, 17 Nov 2010 05:44:19 -0500 Received: from one.firstfloor.org ([213.235.205.2]:56998 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754065Ab0KQKoS (ORCPT ); Wed, 17 Nov 2010 05:44:18 -0500 From: Andi Kleen To: Nick Piggin Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org Subject: Re: [patch 01/28] fs: d_validate fixes References: <20101116140900.039761100@kernel.dk> <20101116142028.254946611@kernel.dk> Date: Wed, 17 Nov 2010 11:44:16 +0100 In-Reply-To: <20101116142028.254946611@kernel.dk> (Nick Piggin's message of "Wed, 17 Nov 2010 01:09:01 +1100") Message-ID: <87bp5orzzz.fsf@basil.nowhere.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 740 Lines: 19 Nick Piggin writes: > d_validate has been broken for a long time. > > kmem_ptr_validate does not guarantee that a pointer can be dereferenced > if it can go away at any time. Even rcu_read_lock doesn't help, because > the pointer might be queued in RCU callbacks but not executed yet. I wonder if that is a problem for NFS ... (which I believe is the only user). Could these races be used to break the NFS server? -Andi -- ak@linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/