From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751779AbZHRXaT (ORCPT ); Tue, 18 Aug 2009 19:30:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751261AbZHRXaS (ORCPT ); Tue, 18 Aug 2009 19:30:18 -0400 Received: from mga09.intel.com ([134.134.136.24]:14119 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751075AbZHRXaR (ORCPT ); Tue, 18 Aug 2009 19:30:17 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.43,404,1246863600"; d="scan'208";a="440418164" Date: Tue, 18 Aug 2009 16:30:17 -0700 From: mgross To: Jonathan Corbet Cc: LKML , Ingo Molnar , Andrew Morton , Frederic Weisbecker Subject: Re: [PATCH 2/2] pm_qos: clean up racy file-global variable Message-ID: <20090818233016.GC16014@linux.intel.com> Reply-To: mgross@linux.intel.com References: <20090813140554.014ce1e0@bike.lwn.net> <20090813140825.0a39d5b6@bike.lwn.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090813140825.0a39d5b6@bike.lwn.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 13, 2009 at 02:08:25PM -0600, Jonathan Corbet wrote: > "name" is a poor name for a file-global variable. It was used in three True. > different functions, with no mutual exclusion. But it's just a tiny, > temporary string; let's just move it onto the stack in the functions that > need it. Also use snprintf() just in case. > Signed-off-by: Mark Gross > Signed-off-by: Jonathan Corbet > Cc: Mark Gross > Reviewed-by: Frederic Weisbecker > --- > kernel/pm_qos_params.c | 12 +++++++----- > 1 files changed, 7 insertions(+), 5 deletions(-) > > diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c > index d96b83e..3db49b9 100644 > --- a/kernel/pm_qos_params.c > +++ b/kernel/pm_qos_params.c > @@ -343,18 +343,18 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier) > } > EXPORT_SYMBOL_GPL(pm_qos_remove_notifier); > > -#define PID_NAME_LEN sizeof("process_1234567890") > -static char name[PID_NAME_LEN]; > +#define PID_NAME_LEN 32 > > static int pm_qos_power_open(struct inode *inode, struct file *filp) > { > int ret; > long pm_qos_class; > + char name[PID_NAME_LEN]; > > pm_qos_class = find_pm_qos_object_by_minor(iminor(inode)); > if (pm_qos_class >= 0) { > filp->private_data = (void *)pm_qos_class; > - sprintf(name, "process_%d", current->pid); > + snprintf(name, PID_NAME_LEN, "process_%d", current->pid); > ret = pm_qos_add_requirement(pm_qos_class, name, > PM_QOS_DEFAULT_VALUE); > if (ret >= 0) > @@ -366,9 +366,10 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp) > static int pm_qos_power_release(struct inode *inode, struct file *filp) > { > int pm_qos_class; > + char name[PID_NAME_LEN]; > > pm_qos_class = (long)filp->private_data; > - sprintf(name, "process_%d", current->pid); > + snprintf(name, PID_NAME_LEN, "process_%d", current->pid); > pm_qos_remove_requirement(pm_qos_class, name); > > return 0; > @@ -379,13 +380,14 @@ static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf, > { > s32 value; > int pm_qos_class; > + char name[PID_NAME_LEN]; > > pm_qos_class = (long)filp->private_data; > if (count != sizeof(s32)) > return -EINVAL; > if (copy_from_user(&value, buf, sizeof(s32))) > return -EFAULT; > - sprintf(name, "process_%d", current->pid); > + snprintf(name, PID_NAME_LEN, "process_%d", current->pid); > pm_qos_update_requirement(pm_qos_class, name, value); > > return sizeof(s32); > -- > 1.6.2.5