From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752283Ab0FVLUM (ORCPT ); Tue, 22 Jun 2010 07:20:12 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:48270 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751397Ab0FVLUK (ORCPT ); Tue, 22 Jun 2010 07:20:10 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=ttMhDl1j6qYDdvNncTS9tHxtGr6MkkQxSe4DGfFPT3nNdCHtmUYIHlItugazycpnVA Rj0w8jzLOeA91pqN93EV3/XjczMCNOE0ISawXHec8mLYhCrp021DTFvH3EfBW/KL90m4 NvIanEl6aZ9ZhrZYkpBOX0opdC2Y6R1y+xxX0= Message-ID: <4C209C6E.3060302@gmail.com> Date: Tue, 22 Jun 2010 13:20:14 +0200 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; cs-CZ; rv:1.9.2.4) Gecko/20100608 SUSE/3.1.0 Thunderbird/3.1 MIME-Version: 1.0 To: borislav.petkov@amd.com CC: "H. Peter Anvin" , x86@kernel.org, Linux kernel mailing list Subject: Re: intel_cacheinfo: potential NULL dereference? References: <4C209C15.9090604@gmail.com> In-Reply-To: <4C209C15.9090604@gmail.com> X-Enigmail-Version: 1.1 Content-Type: text/plain; charset=ISO-8859-2 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 01:18 PM, Jiri Slaby wrote: > Hi, > > commit 9350f982 changed the code so it looks like: > static ssize_t store_cache_disable(struct _cpuid4_info *this_leaf, > const char *buf, size_t count, > unsigned int slot) > { > struct pci_dev *dev = this_leaf->l3->dev; <<1>> > int cpu = cpumask_first(to_cpumask(this_leaf->shared_cpu_map)); > unsigned long val = 0; > > #define SUBCACHE_MASK (3UL << 20) > #define SUBCACHE_INDEX 0xfff > > if (!this_leaf->l3 || !this_leaf->l3->can_disable) <<2>> > return -EINVAL; > > 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. -- js