[PATCH] mfd: fix unintentional NULL check in menelaus_set_voltage()

[PATCH] mfd: fix unintentional NULL check in menelaus_set_voltage()

[Emil Goode]

The struct menelaus_vtg pointer vtg cannot be NULL here
so the condition is never true and if it ever was true
it would lead to a NULL pointer dereference when we goto
label set_voltage.

Before the below patch was applied the code was:

if (vtg == 0)

The intention was to check if vtg_val is 0.

commit 59a9f7a32adf6537b4e4db8ca204eeb77d7a634e
("mfd: menelaus: Use NULL instead of 0")

Signed-off-by: Emil Goode <emilgoode@gmail.com>
---
Hello,

This is only build tested, it would be good to get a comment
from someone who is familiar with this code.

Found using coccinelle.

Best regards,

Emil Goode

 drivers/mfd/menelaus.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mfd/menelaus.c b/drivers/mfd/menelaus.c
index ad25bfa..4859597 100644
--- a/drivers/mfd/menelaus.c
+++ b/drivers/mfd/menelaus.c
@@ -466,7 +466,7 @@ static int menelaus_set_voltage(const struct menelaus_vtg *vtg, int mV,
 	struct i2c_client *c = the_menelaus->client;
 
 	mutex_lock(&the_menelaus->lock);
-	if (!vtg)
+	if (vtg_val == 0)
 		goto set_voltage;
 
 	ret = menelaus_read_reg(vtg->vtg_reg);
-- 
1.7.10.4

Re: [PATCH] mfd: fix unintentional NULL check in menelaus_set_voltage()

[Lee Jones]

On Wed, 28 May 2014, Emil Goode wrote:

> The struct menelaus_vtg pointer vtg cannot be NULL here
> so the condition is never true and if it ever was true
> it would lead to a NULL pointer dereference when we goto
> label set_voltage.
> 
> Before the below patch was applied the code was:
> 
> if (vtg == 0)
> 
> The intention was to check if vtg_val is 0.
> 
> commit 59a9f7a32adf6537b4e4db8ca204eeb77d7a634e
> ("mfd: menelaus: Use NULL instead of 0")
> 
> Signed-off-by: Emil Goode <emilgoode@gmail.com>
> ---
> Hello,
> 
> This is only build tested, it would be good to get a comment
> from someone who is familiar with this code.
> 
> Found using coccinelle.
> 
> Best regards,
> 
> Emil Goode
> 
>  drivers/mfd/menelaus.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/menelaus.c b/drivers/mfd/menelaus.c
> index ad25bfa..4859597 100644
> --- a/drivers/mfd/menelaus.c
> +++ b/drivers/mfd/menelaus.c
> @@ -466,7 +466,7 @@ static int menelaus_set_voltage(const struct menelaus_vtg *vtg, int mV,
>  	struct i2c_client *c = the_menelaus->client;
>  
>  	mutex_lock(&the_menelaus->lock);
> -	if (!vtg)
> +	if (vtg_val == 0)

I would prefer:

  if (!vtg_val)

>  		goto set_voltage;
>  
>  	ret = menelaus_read_reg(vtg->vtg_reg);

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH] mfd: fix unintentional NULL check in menelaus_set_voltage()

[Emil Goode]

Hello,

On Wed, May 28, 2014 at 04:20:11PM +0100, Lee Jones wrote:
> On Wed, 28 May 2014, Emil Goode wrote:
> 
> > The struct menelaus_vtg pointer vtg cannot be NULL here
> > so the condition is never true and if it ever was true
> > it would lead to a NULL pointer dereference when we goto
> > label set_voltage.
> > 
> > Before the below patch was applied the code was:
> > 
> > if (vtg == 0)
> > 
> > The intention was to check if vtg_val is 0.
> > 
> > commit 59a9f7a32adf6537b4e4db8ca204eeb77d7a634e
> > ("mfd: menelaus: Use NULL instead of 0")
> > 
> > Signed-off-by: Emil Goode <emilgoode@gmail.com>
> > ---
> > Hello,
> > 
> > This is only build tested, it would be good to get a comment
> > from someone who is familiar with this code.
> > 
> > Found using coccinelle.
> > 
> > Best regards,
> > 
> > Emil Goode
> > 
> >  drivers/mfd/menelaus.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/mfd/menelaus.c b/drivers/mfd/menelaus.c
> > index ad25bfa..4859597 100644
> > --- a/drivers/mfd/menelaus.c
> > +++ b/drivers/mfd/menelaus.c
> > @@ -466,7 +466,7 @@ static int menelaus_set_voltage(const struct menelaus_vtg *vtg, int mV,
> >  	struct i2c_client *c = the_menelaus->client;
> >  
> >  	mutex_lock(&the_menelaus->lock);
> > -	if (!vtg)
> > +	if (vtg_val == 0)
> 
> I would prefer:
> 
>   if (!vtg_val)

Ok, I will resend.

Best regards,

Emil Goode