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Subject[tip:bkl/core] pm_qos: clean up racy global "name" variable
Commit-ID:  1a6deaea3584fd7af1cad492b1fe0867060b45db
Gitweb: http://git.kernel.org/tip/1a6deaea3584fd7af1cad492b1fe0867060b45db
Author: Jonathan Corbet <corbet@lwn.net>
AuthorDate: Thu, 6 Aug 2009 13:35:44 -0600
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 14 Oct 2009 15:31:10 +0200

pm_qos: clean up racy global "name" variable

"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 <corbet@lwn.net>
LKML-Reference: <20091010153349.113570550@linutronix.de>
Acked-by: Mark Gross <mgross@linux.intel.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
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);

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