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.ku...@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.
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