2014-01-02 04:02:47

by Zhang, Rui

[permalink] [raw]
Subject: Re: [PATCH 1/1] thermal: fix cpu_cooling max_level behavior

On Fri, 2013-12-06 at 09:52 -0400, Eduardo Valentin wrote:
> On 13-11-2013 14:11, Eduardo Valentin wrote:
> > As per Documentation/thermal/sysfs-api.txt, max_level
> > is an index, not a counter. Thus, in case a CPU has
> > 3 valid frequencies, max_level is expected to be 2, for instance.
> >
> > The current code makes max_level == number of valid frequencies,
> > which is bogus. This patch fix the cpu_cooling device by
> > ranging max_level properly.
> >
good catch.
> > Reported-by: Carlos Hernandez <[email protected]>
> > Signed-off-by: Eduardo Valentin <[email protected]>
>
> Rui,
>
> Can you please consider pushing this fix?
>
applied.

> > ---
> > drivers/thermal/cpu_cooling.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
> > index d179028..d0f8f8b5 100644
> > --- a/drivers/thermal/cpu_cooling.c
> > +++ b/drivers/thermal/cpu_cooling.c
> > @@ -173,6 +173,8 @@ static int get_property(unsigned int cpu, unsigned long input,
> > freq = table[i].frequency;
> > max_level++;
> > }
> > + /* max_level is an index, not a counter */
> > + max_level--;
> >
I think we should check the max_level first, like the patch I attached
below.

thanks,
rui

>From a116776f7b6052599df0c67db29c30ea9d69d7ee Mon Sep 17 00:00:00 2001
From: Zhang Rui <[email protected]>
Date: Thu, 2 Jan 2014 11:57:48 +0800
Subject: [PATCH] Thermal cpu cooling: return error if no valid cpu frequency
entry

Signed-off-by: Zhang Rui <[email protected]>
---
drivers/thermal/cpu_cooling.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index cc556a8..bb486b4 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -173,6 +173,11 @@ static int get_property(unsigned int cpu, unsigned long input,
freq = table[i].frequency;
max_level++;
}
+
+ /* No valid cpu frequency entry */
+ if (max_level == 0)
+ return -EINVAL;
+
/* max_level is an index, not a counter */
max_level--;

--
1.7.9.5



2014-01-04 13:53:38

by Eduardo Valentin

[permalink] [raw]
Subject: Re: [PATCH 1/1] thermal: fix cpu_cooling max_level behavior

On 02-01-2014 00:02, Zhang Rui wrote:
> On Fri, 2013-12-06 at 09:52 -0400, Eduardo Valentin wrote:
>> On 13-11-2013 14:11, Eduardo Valentin wrote:
>>> As per Documentation/thermal/sysfs-api.txt, max_level
>>> is an index, not a counter. Thus, in case a CPU has
>>> 3 valid frequencies, max_level is expected to be 2, for instance.
>>>
>>> The current code makes max_level == number of valid frequencies,
>>> which is bogus. This patch fix the cpu_cooling device by
>>> ranging max_level properly.
>>>
> good catch.
>>> Reported-by: Carlos Hernandez <[email protected]>
>>> Signed-off-by: Eduardo Valentin <[email protected]>
>>
>> Rui,
>>
>> Can you please consider pushing this fix?
>>
> applied.
>
>>> ---
>>> drivers/thermal/cpu_cooling.c | 6 ++++--
>>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
>>> index d179028..d0f8f8b5 100644
>>> --- a/drivers/thermal/cpu_cooling.c
>>> +++ b/drivers/thermal/cpu_cooling.c
>>> @@ -173,6 +173,8 @@ static int get_property(unsigned int cpu, unsigned long input,
>>> freq = table[i].frequency;
>>> max_level++;
>>> }
>>> + /* max_level is an index, not a counter */
>>> + max_level--;
>>>
> I think we should check the max_level first, like the patch I attached
> below.
>
> thanks,
> rui
>
>>From a116776f7b6052599df0c67db29c30ea9d69d7ee Mon Sep 17 00:00:00 2001
> From: Zhang Rui <[email protected]>
> Date: Thu, 2 Jan 2014 11:57:48 +0800
> Subject: [PATCH] Thermal cpu cooling: return error if no valid cpu frequency
> entry
>
> Signed-off-by: Zhang Rui <[email protected]>
> ---
> drivers/thermal/cpu_cooling.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
> index cc556a8..bb486b4 100644
> --- a/drivers/thermal/cpu_cooling.c
> +++ b/drivers/thermal/cpu_cooling.c
> @@ -173,6 +173,11 @@ static int get_property(unsigned int cpu, unsigned long input,
> freq = table[i].frequency;
> max_level++;
> }
> +
> + /* No valid cpu frequency entry */
> + if (max_level == 0)
> + return -EINVAL;
> +

Agreed. For the patch above:

Acked-by: Eduardo Valentin <[email protected]>

> /* max_level is an index, not a counter */
> max_level--;
>
>


--
You have got to be excited about what you are doing. (L. Lamport)

Eduardo Valentin


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