* [PATCH] cpufreq: check cpufreq driver is valid and cpufreq isn't disabled in cpufreq_get()
@ 2013-09-20 17:07 Viresh Kumar
2013-09-21 5:51 ` Srivatsa S. Bhat
0 siblings, 1 reply; 2+ messages in thread
From: Viresh Kumar @ 2013-09-20 17:07 UTC (permalink / raw)
To: rjw
Cc: linaro-kernel, patches, cpufreq, linux-pm, linux-kernel,
srivatsa.bhat, linus.walleij, Viresh Kumar
cpufreq_get() can be called from external drivers which might not be aware if
cpufreq driver is registered or not. And so we should actually check if cpufreq
driver is registered or not and also if cpufreq is active or disabled, at the
beginning of cpufreq_get().
Otherwise call to lock_policy_rwsem_read() might hit BUG_ON(!policy).
Reported-and-Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
For 3.12.
drivers/cpufreq/cpufreq.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 82ecbe3..db004a8 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1460,6 +1460,9 @@ unsigned int cpufreq_get(unsigned int cpu)
{
unsigned int ret_freq = 0;
+ if (cpufreq_disabled() || !cpufreq_driver)
+ return -ENOENT;
+
if (!down_read_trylock(&cpufreq_rwsem))
return 0;
--
1.7.12.rc2.18.g61b472e
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] cpufreq: check cpufreq driver is valid and cpufreq isn't disabled in cpufreq_get()
2013-09-20 17:07 [PATCH] cpufreq: check cpufreq driver is valid and cpufreq isn't disabled in cpufreq_get() Viresh Kumar
@ 2013-09-21 5:51 ` Srivatsa S. Bhat
0 siblings, 0 replies; 2+ messages in thread
From: Srivatsa S. Bhat @ 2013-09-21 5:51 UTC (permalink / raw)
To: Viresh Kumar
Cc: rjw, linaro-kernel, patches, cpufreq, linux-pm, linux-kernel,
linus.walleij
On 09/20/2013 10:37 PM, Viresh Kumar wrote:
> cpufreq_get() can be called from external drivers which might not be aware if
> cpufreq driver is registered or not. And so we should actually check if cpufreq
> driver is registered or not and also if cpufreq is active or disabled, at the
> beginning of cpufreq_get().
>
> Otherwise call to lock_policy_rwsem_read() might hit BUG_ON(!policy).
>
> Reported-and-Tested-by: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Regards,
Srivatsa S. Bhat
>
> For 3.12.
>
> drivers/cpufreq/cpufreq.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 82ecbe3..db004a8 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1460,6 +1460,9 @@ unsigned int cpufreq_get(unsigned int cpu)
> {
> unsigned int ret_freq = 0;
>
> + if (cpufreq_disabled() || !cpufreq_driver)
> + return -ENOENT;
> +
> if (!down_read_trylock(&cpufreq_rwsem))
> return 0;
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2013-09-20 17:07 [PATCH] cpufreq: check cpufreq driver is valid and cpufreq isn't disabled in cpufreq_get() Viresh Kumar
2013-09-21 5:51 ` Srivatsa S. Bhat
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