From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932376AbZHMULR (ORCPT ); Thu, 13 Aug 2009 16:11:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932153AbZHMULO (ORCPT ); Thu, 13 Aug 2009 16:11:14 -0400 Received: from vena.lwn.net ([206.168.112.25]:46274 "EHLO vena.lwn.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932373AbZHMULL (ORCPT ); Thu, 13 Aug 2009 16:11:11 -0400 Date: Thu, 13 Aug 2009 14:08:25 -0600 From: Jonathan Corbet To: LKML Cc: Ingo Molnar , Mark Gross , Andrew Morton , Frederic Weisbecker Subject: [PATCH 2/2] pm_qos: clean up racy file-global variable Message-ID: <20090813140825.0a39d5b6@bike.lwn.net> In-Reply-To: <20090813140554.014ce1e0@bike.lwn.net> References: <20090813140554.014ce1e0@bike.lwn.net> Organization: LWN.net X-Mailer: Claws Mail 3.7.2 (GTK+ 2.16.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "name" is a poor name for a file-global variable. It was used in three 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: 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