From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755895Ab0FVRJ7 (ORCPT ); Tue, 22 Jun 2010 13:09:59 -0400 Received: from terminus.zytor.com ([198.137.202.10]:55938 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752542Ab0FVRJ6 (ORCPT ); Tue, 22 Jun 2010 13:09:58 -0400 Message-ID: <4C20EE54.2050506@zytor.com> Date: Tue, 22 Jun 2010 10:09:40 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-3.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Jiri Slaby CC: Borislav Petkov , "x86@kernel.org" , Linux kernel mailing list Subject: Re: intel_cacheinfo: potential NULL dereference? References: <4C209C15.9090604@gmail.com> <4C209C6E.3060302@gmail.com> <20100622130825.GB27658@aftab> <4C20C478.9030505@gmail.com> In-Reply-To: <4C20C478.9030505@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/22/2010 07:11 AM, Jiri Slaby wrote: > On 06/22/2010 03:08 PM, Borislav Petkov wrote: >> From: Jiri Slaby >> Date: Tue, Jun 22, 2010 at 07:20:14AM -0400 >> >>> On 06/22/2010 01:18 PM, Jiri Slaby wrote: >>>> Stanse found, that this_leaf->l3 is dereferenced at <<1>>, but checked >>>> for being NULL at <<2>>. Is the check superfluous or the dev assignment >>>> should go after the check? >>> >>> Oh, and I have another report with same symptoms for show_cache_disable. >> >> Right, so I have a patch in tip/x86/cpu >> (8cc1176e5de534d55cb26ff0cef3fd0d6ad8c3c0) which reorganizes >> and cleans up that code. With it, all possible checks land in >> amd_check_l3_disable() and if they have all been passed, the PCI dev is >> guaranteed to be properly set. So no need for sprinkling additional NULL >> checks in the code. >> >> How's that? > > Looks good. > Do we need a patch for the existing code to go into -linus and -stable, though? -hpa