From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757820Ab0CaAeT (ORCPT ); Tue, 30 Mar 2010 20:34:19 -0400 Received: from kroah.org ([198.145.64.141]:48769 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756252Ab0C3XLw (ORCPT ); Tue, 30 Mar 2010 19:11:52 -0400 X-Mailbox-Line: From linux@linux.site Tue Mar 30 15:58:13 2010 Message-Id: <20100330225813.099145953@linux.site> User-Agent: quilt/0.47-14.9 Date: Tue, 30 Mar 2010 15:57:10 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Thomas Renninger , Dave Jones , Greg Kroah-Hartman Subject: [08/89] CPUFREQ: Fix use after free of struct powernow_k8_data In-Reply-To: <20100330230520.GA28779@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.31-stable review patch. If anyone has any objections, please let us know. ------------------ From: Thomas Renninger commit 557a701c16553b0b691dbb64ef30361115a80f64 upstream. Easy fix for a regression introduced in 2.6.31. On managed CPUs the cpufreq.c core will call driver->exit(cpu) on the managed cpus and powernow_k8 will free the core's data. Later driver->get(cpu) function might get called trying to read out the current freq of a managed cpu and the NULL pointer check does not work on the freed object -> better set it to NULL. ->get() is unsigned and must return 0 as invalid frequency. Reference: http://bugzilla.kernel.org/show_bug.cgi?id=14391 Signed-off-by: Thomas Renninger Tested-by: Michal Schmidt Signed-off-by: Dave Jones Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/cpufreq/powernow-k8.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c +++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c @@ -1372,6 +1372,7 @@ static int __devexit powernowk8_cpu_exit kfree(data->powernow_table); kfree(data); + per_cpu(powernow_data, pol->cpu) = NULL; return 0; } @@ -1391,7 +1392,7 @@ static unsigned int powernowk8_get(unsig int err; if (!data) - return -EINVAL; + return 0; smp_call_function_single(cpu, query_values_on_cpu, &err, true); if (err)