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SubjectRe: linux-next: build warning after merge of the suspend tree
Date
On Monday, May 23, 2011, mark gross wrote:
> On Mon, May 23, 2011 at 03:06:36PM +1000, Stephen Rothwell wrote:
> > Hi Rafael,
> >
> > After merging the suspend tree, today's linux-next build (i386 defconfig
> > among others) produced this warning:
> >
> > kernel/pm_qos_params.c: In function 'pm_qos_power_write':
> > kernel/pm_qos_params.c:420: warning: passing argument 3 of 'kstrtol' from incompatible pointer type
> > include/linux/kernel.h:210: note: expected 'long int *' but argument is of type 's32 *'
> >
> > Intreoduced by commit 365daa955e03 ("PM: Correct PM QOS's user mode
> > interface to work with ascii input per").
>
> Gah! I'm sorry about that.
>
> attached is a fix.
>
>
> --mark
>
> signed-off-by:markgross <markgross@thegnar.org>
>
>
>
> From a8f0587b9ae598be5ca4c3cdda4e0ced6ca9baaf Mon Sep 17 00:00:00 2001
> From: mgross <mgross@cr48>
> Date: Mon, 23 May 2011 07:14:09 -0700
> Subject: [PATCH] clean up a compile time warning in the use of strict_strtol but that was
> passing an s32 * when it should be passing a long *
>
> ---
> kernel/pm_qos_params.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
> index d61ecf3..dd37c56 100644
> --- a/kernel/pm_qos_params.c
> +++ b/kernel/pm_qos_params.c
> @@ -405,6 +405,7 @@ static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
> size_t count, loff_t *f_pos)
> {
> s32 value;
> + long safe_int;
> int x;
> char ascii_value[11];
> struct pm_qos_request_list *pm_qos_req;
> @@ -417,10 +418,11 @@ static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
> ascii_value[count] = 0;
> if (copy_from_user(ascii_value, buf, count))
> return -EFAULT;
> - if ((x=strict_strtol(ascii_value, 16, &value)) != 0){
> - pr_debug("%s, 0x%x, 0x%x\n",ascii_value, value, x);
> + if ((x=strict_strtol(ascii_value, 16, &safe_int)) != 0){
> + pr_debug("%s, 0x%lx, 0x%x\n",ascii_value, safe_int, x);
> return -EINVAL;
> }
> + value = (s32) safe_int;

Well, this doesn't seem quite right.

> } else
> return -EINVAL;

Besides, if count == 11, there we'll write beyond ascii_value[], right?

What about the appended patch instead of your original one?

Rafael


---
From: mark gross <markgross@thegnar.org>
Subject: PM: Correct PM QOS's user mode interface to work with ascii input per

What is in the kernel docs. Writing a string to the ABI from user mode
comes in 2 flavors. One with and one without a '\n' at the end. This
change accepts both.

# echo 0x12345678 > /dev/cpu_dma_latency

and

# echo -n 0x12345678 > /dev/cpu_dma_latency

now both work.

[rjw: Fixed up array bounds checking and type casting.]

Signed-off-by: mark gross <markgross@thegnar.org>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
kernel/pm_qos_params.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)

Index: linux-2.6/kernel/pm_qos_params.c
===================================================================
--- linux-2.6.orig/kernel/pm_qos_params.c
+++ linux-2.6/kernel/pm_qos_params.c
@@ -40,6 +40,7 @@
#include <linux/string.h>
#include <linux/platform_device.h>
#include <linux/init.h>
+#include <linux/kernel.h>

#include <linux/uaccess.h>

@@ -404,24 +405,30 @@ static ssize_t pm_qos_power_write(struct
size_t count, loff_t *f_pos)
{
s32 value;
- int x;
char ascii_value[11];
struct pm_qos_request_list *pm_qos_req;

if (count == sizeof(s32)) {
if (copy_from_user(&value, buf, sizeof(s32)))
return -EFAULT;
- } else if (count == 11) { /* len('0x12345678/0') */
- if (copy_from_user(ascii_value, buf, 11))
+ } else if (count >= 10) { /* '0x12345678' or '0x12345678\n'*/
+ unsigned long int ulval;
+ int ret;
+
+ count = 10;
+ ascii_value[count] = 0;
+ if (copy_from_user(ascii_value, buf, count))
return -EFAULT;
- if (strlen(ascii_value) != 10)
- return -EINVAL;
- x = sscanf(ascii_value, "%x", &value);
- if (x != 1)
+
+ ret = strict_strtoul(ascii_value, 16, &ulval);
+ if (ret){
+ pr_debug("%s, 0x%lx, 0x%x\n", ascii_value, ulval, ret);
return -EINVAL;
- pr_debug("%s, %d, 0x%x\n", ascii_value, x, value);
- } else
+ }
+ value = (s32)lower_32_bits(ulval);
+ } else {
return -EINVAL;
+ }

pm_qos_req = filp->private_data;
pm_qos_update_request(pm_qos_req, value);

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