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[PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning

Started byCaesar Wang <wxt@rock-chips.com>
First post2015-12-03 09:50 +0100
Last post2015-12-03 21:50 +0100
Articles 4 — 3 participants

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  [PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning Caesar Wang <wxt@rock-chips.com> - 2015-12-03 09:50 +0100
    Re: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition  caused by the warning Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-12-03 21:20 +0100
      Re: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition  caused by the warning Brian Norris <computersforpeace@gmail.com> - 2015-12-03 21:40 +0100
        Re: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition  caused by the warning Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-12-03 21:50 +0100

#1282805 — [PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning

FromCaesar Wang <wxt@rock-chips.com>
Date2015-12-03 09:50 +0100
Subject[PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning
Message-ID<qBxKq-2zO-9@gated-at.bofh.it>
As the Dan report the smatch check the thermal driver warning:
drivers/thermal/rockchip_thermal.c:551 rockchip_configure_from_dt()
warn: impossible condition '(thermal->tshut_temp > ((~0 >> 1))) =>
(s32min-s32max > s32max)'

Let's we remove the imposssible condition Since the Temperature is
currently represented as int not long in the thermal driver.

Fixes: commit 437df2172e8d
("thermal: rockchip: consistently use int for temperatures")

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>

---

Changes in v3:
- As Brian comments on https://patchwork.kernel.org/patch/7580661/,
  let's remove the impossible condition.

Changes in v2: None
Changes in v1: None

 drivers/thermal/rockchip_thermal.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
index ae796ec..611de00 100644
--- a/drivers/thermal/rockchip_thermal.c
+++ b/drivers/thermal/rockchip_thermal.c
@@ -549,12 +549,6 @@ static int rockchip_configure_from_dt(struct device *dev,
 		thermal->tshut_temp = shut_temp;
 	}
 
-	if (thermal->tshut_temp > INT_MAX) {
-		dev_err(dev, "Invalid tshut temperature specified: %d\n",
-			thermal->tshut_temp);
-		return -ERANGE;
-	}
-
 	if (of_property_read_u32(np, "rockchip,hw-tshut-mode", &tshut_mode)) {
 		dev_warn(dev,
 			 "Missing tshut mode property, using default (%s)\n",
-- 
1.9.1

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#1283309 — Re: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning

FromDmitry Torokhov <dmitry.torokhov@gmail.com>
Date2015-12-03 21:20 +0100
SubjectRe: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning
Message-ID<qBIwa-1o5-5@gated-at.bofh.it>
In reply to#1282805
On Thu, Dec 03, 2015 at 04:48:40PM +0800, Caesar Wang wrote:
> As the Dan report the smatch check the thermal driver warning:
> drivers/thermal/rockchip_thermal.c:551 rockchip_configure_from_dt()
> warn: impossible condition '(thermal->tshut_temp > ((~0 >> 1))) =>
> (s32min-s32max > s32max)'
> 
> Let's we remove the imposssible condition Since the Temperature is
> currently represented as int not long in the thermal driver.
> 
> Fixes: commit 437df2172e8d
> ("thermal: rockchip: consistently use int for temperatures")
> 
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> 
> ---
> 
> Changes in v3:
> - As Brian comments on https://patchwork.kernel.org/patch/7580661/,
>   let's remove the impossible condition.
> 
> Changes in v2: None
> Changes in v1: None
> 
>  drivers/thermal/rockchip_thermal.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
> index ae796ec..611de00 100644
> --- a/drivers/thermal/rockchip_thermal.c
> +++ b/drivers/thermal/rockchip_thermal.c
> @@ -549,12 +549,6 @@ static int rockchip_configure_from_dt(struct device *dev,
>  		thermal->tshut_temp = shut_temp;
>  	}
>  
> -	if (thermal->tshut_temp > INT_MAX) {
> -		dev_err(dev, "Invalid tshut temperature specified: %d\n",
> -			thermal->tshut_temp);
> -		return -ERANGE;
> -	}

Well, that is not entirely correct. The value that we read from DT is
u32, but we convert it down to int. I believe you want to move the check
up so that you do:

	} else if (tshut_temp > INT_MAX) {
		dev_err(dev, "Invalid tshut temperature specified: %d\n",
			thermal->tshut_temp);
		return -ERANGE;
	} else {
		thermal->tshut_temp = shut_temp;
	}

Thanks.

-- 
Dmitry
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#1283323 — Re: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning

FromBrian Norris <computersforpeace@gmail.com>
Date2015-12-03 21:40 +0100
SubjectRe: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning
Message-ID<qBIPv-1uA-5@gated-at.bofh.it>
In reply to#1283309
On Thu, Dec 03, 2015 at 12:19:08PM -0800, Dmitry Torokhov wrote:
> On Thu, Dec 03, 2015 at 04:48:40PM +0800, Caesar Wang wrote:
> > As the Dan report the smatch check the thermal driver warning:
> > drivers/thermal/rockchip_thermal.c:551 rockchip_configure_from_dt()
> > warn: impossible condition '(thermal->tshut_temp > ((~0 >> 1))) =>
> > (s32min-s32max > s32max)'
> > 
> > Let's we remove the imposssible condition Since the Temperature is
> > currently represented as int not long in the thermal driver.
> > 
> > Fixes: commit 437df2172e8d
> > ("thermal: rockchip: consistently use int for temperatures")
> > 
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> > 
> > ---
> > 
> > Changes in v3:
> > - As Brian comments on https://patchwork.kernel.org/patch/7580661/,
> >   let's remove the impossible condition.
> > 
> > Changes in v2: None
> > Changes in v1: None
> > 
> >  drivers/thermal/rockchip_thermal.c | 6 ------
> >  1 file changed, 6 deletions(-)
> > 
> > diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
> > index ae796ec..611de00 100644
> > --- a/drivers/thermal/rockchip_thermal.c
> > +++ b/drivers/thermal/rockchip_thermal.c
> > @@ -549,12 +549,6 @@ static int rockchip_configure_from_dt(struct device *dev,
> >  		thermal->tshut_temp = shut_temp;
> >  	}
> >  
> > -	if (thermal->tshut_temp > INT_MAX) {
> > -		dev_err(dev, "Invalid tshut temperature specified: %d\n",
> > -			thermal->tshut_temp);
> > -		return -ERANGE;
> > -	}
> 
> Well, that is not entirely correct. The value that we read from DT is
> u32, but we convert it down to int. I believe you want to move the check

Do we really account for the possibility of sizeof(int) < sizeof(u32)?

EDIT: A bit after writing the above line, I notice my error, but in case
anyone else is thinking the same thing... I guess you're referring to
the sign bit, since we're casting unsigned to signed.

Brian

> up so that you do:
> 
> 	} else if (tshut_temp > INT_MAX) {
> 		dev_err(dev, "Invalid tshut temperature specified: %d\n",
> 			thermal->tshut_temp);
> 		return -ERANGE;
> 	} else {
> 		thermal->tshut_temp = shut_temp;
> 	}
> 
> Thanks.
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#1283331 — Re: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning

FromDmitry Torokhov <dmitry.torokhov@gmail.com>
Date2015-12-03 21:50 +0100
SubjectRe: [PATCH v3 2/5] thermal: rockchip: fix a impossible condition caused by the warning
Message-ID<qBIZb-1y2-13@gated-at.bofh.it>
In reply to#1283323
On Thu, Dec 03, 2015 at 12:33:57PM -0800, Brian Norris wrote:
> On Thu, Dec 03, 2015 at 12:19:08PM -0800, Dmitry Torokhov wrote:
> > On Thu, Dec 03, 2015 at 04:48:40PM +0800, Caesar Wang wrote:
> > > As the Dan report the smatch check the thermal driver warning:
> > > drivers/thermal/rockchip_thermal.c:551 rockchip_configure_from_dt()
> > > warn: impossible condition '(thermal->tshut_temp > ((~0 >> 1))) =>
> > > (s32min-s32max > s32max)'
> > > 
> > > Let's we remove the imposssible condition Since the Temperature is
> > > currently represented as int not long in the thermal driver.
> > > 
> > > Fixes: commit 437df2172e8d
> > > ("thermal: rockchip: consistently use int for temperatures")
> > > 
> > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > > Signed-off-by: Caesar Wang <wxt@rock-chips.com>
> > > 
> > > ---
> > > 
> > > Changes in v3:
> > > - As Brian comments on https://patchwork.kernel.org/patch/7580661/,
> > >   let's remove the impossible condition.
> > > 
> > > Changes in v2: None
> > > Changes in v1: None
> > > 
> > >  drivers/thermal/rockchip_thermal.c | 6 ------
> > >  1 file changed, 6 deletions(-)
> > > 
> > > diff --git a/drivers/thermal/rockchip_thermal.c b/drivers/thermal/rockchip_thermal.c
> > > index ae796ec..611de00 100644
> > > --- a/drivers/thermal/rockchip_thermal.c
> > > +++ b/drivers/thermal/rockchip_thermal.c
> > > @@ -549,12 +549,6 @@ static int rockchip_configure_from_dt(struct device *dev,
> > >  		thermal->tshut_temp = shut_temp;
> > >  	}
> > >  
> > > -	if (thermal->tshut_temp > INT_MAX) {
> > > -		dev_err(dev, "Invalid tshut temperature specified: %d\n",
> > > -			thermal->tshut_temp);
> > > -		return -ERANGE;
> > > -	}
> > 
> > Well, that is not entirely correct. The value that we read from DT is
> > u32, but we convert it down to int. I believe you want to move the check
> 
> Do we really account for the possibility of sizeof(int) < sizeof(u32)?
> 
> EDIT: A bit after writing the above line, I notice my error, but in case
> anyone else is thinking the same thing... I guess you're referring to
> the sign bit, since we're casting unsigned to signed.

Yes, exactly. Sorry I was not clear.

-- 
Dmitry
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