thermal: tegra: dereference the pointer after null check

Message ID 1504223549-4152-1-git-send-email-nicoleotsuka@gmail.com
State New
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Series
  • thermal: tegra: dereference the pointer after null check
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Commit Message

Nicolin Chen Aug. 31, 2017, 11:52 p.m.
The dev pointer is going through a null check after a dereference.
So this patch just reverses that.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 drivers/thermal/tegra/soctherm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Thierry Reding Sept. 1, 2017, 7:08 p.m. | #1
On Thu, Aug 31, 2017 at 04:52:29PM -0700, Nicolin Chen wrote:
> The dev pointer is going through a null check after a dereference.
> So this patch just reverses that.
> 
> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
> ---
>  drivers/thermal/tegra/soctherm.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c
> index 7d2db23..6718799 100644
> --- a/drivers/thermal/tegra/soctherm.c
> +++ b/drivers/thermal/tegra/soctherm.c
> @@ -478,7 +478,7 @@ static int throttrip_program(struct device *dev,
>  			     struct soctherm_throt_cfg *stc,
>  			     int trip_temp)
>  {
> -	struct tegra_soctherm *ts = dev_get_drvdata(dev);
> +	struct tegra_soctherm *ts;
>  	int temp, cpu_throt, gpu_throt;
>  	unsigned int throt;
>  	u32 r, reg_off;
> @@ -486,6 +486,8 @@ static int throttrip_program(struct device *dev,
>  	if (!dev || !sg || !stc || !stc->init)
>  		return -EINVAL;
>  
> +	ts = dev_get_drvdata(dev);
> +
>  	temp = enforce_temp_range(dev, trip_temp) / ts->soc->thresh_grain;
>  
>  	/* Hardcode LIGHT on LEVEL1 and HEAVY on LEVEL2 */

I don't see a case where dev is ever going to be NULL here. Therefore, I
think a better patch would be to just drop the !dev test and leave the
rest of the code as-is.

Thierry

Patch

diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c
index 7d2db23..6718799 100644
--- a/drivers/thermal/tegra/soctherm.c
+++ b/drivers/thermal/tegra/soctherm.c
@@ -478,7 +478,7 @@  static int throttrip_program(struct device *dev,
 			     struct soctherm_throt_cfg *stc,
 			     int trip_temp)
 {
-	struct tegra_soctherm *ts = dev_get_drvdata(dev);
+	struct tegra_soctherm *ts;
 	int temp, cpu_throt, gpu_throt;
 	unsigned int throt;
 	u32 r, reg_off;
@@ -486,6 +486,8 @@  static int throttrip_program(struct device *dev,
 	if (!dev || !sg || !stc || !stc->init)
 		return -EINVAL;
 
+	ts = dev_get_drvdata(dev);
+
 	temp = enforce_temp_range(dev, trip_temp) / ts->soc->thresh_grain;
 
 	/* Hardcode LIGHT on LEVEL1 and HEAVY on LEVEL2 */