[PATCH] cpufreq:core: Fix printing of governor and driver name

[PATCH] cpufreq:core: Fix printing of governor and driver name

[Viresh Kumar]

Arrays for governer and driver name are of size CPUFREQ_NAME_LEN or 16.
i.e. 15 bytes for name and 1 for trailing '\0'.

When cpufreq driver print these names (for sysfs), it includes '\n' or ' ' in
the fmt string and still passes length as CPUFREQ_NAME_LEN. If the driver or
governor names are using all 15 fields allocated to them, then the trailing '\n'
or ' ' will never be printed. And so commands like:

root@linaro-developer# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver

will print something like:

cpufreq_foodrvroot@linaro-developer#

Fix this by increasing print length by one character.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/cpufreq/cpufreq.c | 6 +++---
 include/linux/cpufreq.h   | 2 ++
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 021973b..db6e337 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -445,7 +445,7 @@ static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
 	else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
 		return sprintf(buf, "performance\n");
 	else if (policy->governor)
-		return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
+		return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
 				policy->governor->name);
 	return -EINVAL;
 }
@@ -491,7 +491,7 @@ static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
  */
 static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
 {
-	return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
+	return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
 }
 
 /**
@@ -512,7 +512,7 @@ static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
 		if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
 		    - (CPUFREQ_NAME_LEN + 2)))
 			goto out;
-		i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
+		i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
 	}
 out:
 	i += sprintf(&buf[i], "\n");
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index b60f6ba..fc4b785 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -22,6 +22,8 @@
 #include <asm/div64.h>
 
 #define CPUFREQ_NAME_LEN 16
+/* Print length for names. Extra 1 space for accomodating '\n' in prints */
+#define CPUFREQ_NAME_PLEN (CPUFREQ_NAME_LEN + 1)
 
 
 /*********************************************************************
-- 
1.7.12.rc2.18.g61b472e

Re: [PATCH] cpufreq:core: Fix printing of governor and driver name

[Rafael J. Wysocki]

On Wednesday 10 of October 2012 10:12:11 Viresh Kumar wrote:
> Arrays for governer and driver name are of size CPUFREQ_NAME_LEN or 16.
> i.e. 15 bytes for name and 1 for trailing '\0'.
> 
> When cpufreq driver print these names (for sysfs), it includes '\n' or ' ' in
> the fmt string and still passes length as CPUFREQ_NAME_LEN. If the driver or
> governor names are using all 15 fields allocated to them, then the trailing '\n'
> or ' ' will never be printed. And so commands like:
> 
> root@linaro-developer# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
> 
> will print something like:
> 
> cpufreq_foodrvroot@linaro-developer#
> 
> Fix this by increasing print length by one character.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Thanks for the patch, I'll queue it up for v3.8.

Rafael


> ---
>  drivers/cpufreq/cpufreq.c | 6 +++---
>  include/linux/cpufreq.h   | 2 ++
>  2 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 021973b..db6e337 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -445,7 +445,7 @@ static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
>  	else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
>  		return sprintf(buf, "performance\n");
>  	else if (policy->governor)
> -		return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n",
> +		return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
>  				policy->governor->name);
>  	return -EINVAL;
>  }
> @@ -491,7 +491,7 @@ static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
>   */
>  static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
>  {
> -	return scnprintf(buf, CPUFREQ_NAME_LEN, "%s\n", cpufreq_driver->name);
> +	return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
>  }
>  
>  /**
> @@ -512,7 +512,7 @@ static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
>  		if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
>  		    - (CPUFREQ_NAME_LEN + 2)))
>  			goto out;
> -		i += scnprintf(&buf[i], CPUFREQ_NAME_LEN, "%s ", t->name);
> +		i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
>  	}
>  out:
>  	i += sprintf(&buf[i], "\n");
> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
> index b60f6ba..fc4b785 100644
> --- a/include/linux/cpufreq.h
> +++ b/include/linux/cpufreq.h
> @@ -22,6 +22,8 @@
>  #include <asm/div64.h>
>  
>  #define CPUFREQ_NAME_LEN 16
> +/* Print length for names. Extra 1 space for accomodating '\n' in prints */
> +#define CPUFREQ_NAME_PLEN (CPUFREQ_NAME_LEN + 1)
>  
>  
>  /*********************************************************************
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

Re: [PATCH] cpufreq:core: Fix printing of governor and driver name

[Viresh Kumar]

On 15 October 2012 23:21, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> On Wednesday 10 of October 2012 10:12:11 Viresh Kumar wrote:
>> Arrays for governer and driver name are of size CPUFREQ_NAME_LEN or 16.
>> i.e. 15 bytes for name and 1 for trailing '\0'.
>>
>> When cpufreq driver print these names (for sysfs), it includes '\n' or ' ' in
>> the fmt string and still passes length as CPUFREQ_NAME_LEN. If the driver or
>> governor names are using all 15 fields allocated to them, then the trailing '\n'
>> or ' ' will never be printed. And so commands like:
>>
>> root@linaro-developer# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
>>
>> will print something like:
>>
>> cpufreq_foodrvroot@linaro-developer#
>>
>> Fix this by increasing print length by one character.
>>
>> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> Thanks for the patch, I'll queue it up for v3.8.

Hi Rafael,

Thanks for accepting the patch.
I thought both of my patches would go in 3.7-rc2 as they are bug
fixes. Isn't that correct?

--
viresh

Re: [PATCH] cpufreq:core: Fix printing of governor and driver name

[Rafael J. Wysocki]

On Tuesday 16 of October 2012 09:09:15 Viresh Kumar wrote:
> On 15 October 2012 23:21, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > On Wednesday 10 of October 2012 10:12:11 Viresh Kumar wrote:
> >> Arrays for governer and driver name are of size CPUFREQ_NAME_LEN or 16.
> >> i.e. 15 bytes for name and 1 for trailing '\0'.
> >>
> >> When cpufreq driver print these names (for sysfs), it includes '\n' or ' ' in
> >> the fmt string and still passes length as CPUFREQ_NAME_LEN. If the driver or
> >> governor names are using all 15 fields allocated to them, then the trailing '\n'
> >> or ' ' will never be printed. And so commands like:
> >>
> >> root@linaro-developer# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
> >>
> >> will print something like:
> >>
> >> cpufreq_foodrvroot@linaro-developer#
> >>
> >> Fix this by increasing print length by one character.
> >>
> >> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> >
> > Thanks for the patch, I'll queue it up for v3.8.
> 
> Hi Rafael,
> 
> Thanks for accepting the patch.
> I thought both of my patches would go in 3.7-rc2 as they are bug
> fixes. Isn't that correct?

They don't fix serious bugs, though, so they don't look like urgent.

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.