[PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc

[PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc

[Rickard Strandqvist]

After discussion with especially Wolfram and Jingoo it was decided to convert the code to use the Managed Device Resource.
I lack this kind of hardware so preferably should someone do a HW test.

Rickard Strandqvist (1):
  i2c: busses: i2c-pxa.c:  Fix for possible null pointer dereferenc

 drivers/i2c/busses/i2c-pxa.c |   37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

-- 
1.7.10.4

[PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc

[Rickard Strandqvist]

Fix for possible null pointer dereferenc, and there is a risk for memory leak if something unexpected happens and the function returns.
It now use Managed Device Resource instead.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
---
 drivers/i2c/busses/i2c-pxa.c |   37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index be671f7..2edb633 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -1141,10 +1141,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
 	struct resource *res = NULL;
 	int ret, irq;
 
-	i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
+	i2c = devm_kzalloc(&dev->dev, sizeof(struct pxa_i2c), GFP_KERNEL);
 	if (!i2c) {
 		ret = -ENOMEM;
-		goto emalloc;
+		goto err_nothing_to_release;
 	}
 
 	/* Default adapter num to device id; i2c_pxa_probe_dt can override. */
@@ -1154,18 +1154,19 @@ static int i2c_pxa_probe(struct platform_device *dev)
 	if (ret > 0)
 		ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type);
 	if (ret < 0)
-		goto eclk;
+		goto err_nothing_to_release;
 
 	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 	irq = platform_get_irq(dev, 0);
 	if (res == NULL || irq < 0) {
 		ret = -ENODEV;
-		goto eclk;
+		goto err_nothing_to_release;
 	}
 
-	if (!request_mem_region(res->start, resource_size(res), res->name)) {
+	if (!devm_request_mem_region(&dev->dev, res->start,
+				resource_size(res), res->name)) {
 		ret = -ENOMEM;
-		goto eclk;
+		goto emalloc;
 	}
 
 	i2c->adap.owner   = THIS_MODULE;
@@ -1176,16 +1177,16 @@ static int i2c_pxa_probe(struct platform_device *dev)
 
 	strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name));
 
-	i2c->clk = clk_get(&dev->dev, NULL);
+	i2c->clk = devm_clk_get(&dev->dev, NULL);
 	if (IS_ERR(i2c->clk)) {
 		ret = PTR_ERR(i2c->clk);
-		goto eclk;
+		goto emalloc;
 	}
 
-	i2c->reg_base = ioremap(res->start, resource_size(res));
-	if (!i2c->reg_base) {
+	i2c->reg_base = devm_ioremap_resource(&adev->dev, res));
+	if (IS_ERR(i2c->reg_base)) {
 		ret = -EIO;
-		goto eremap;
+		goto emalloc;
 	}
 
 	i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr;
@@ -1227,10 +1228,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
 		i2c->adap.algo = &i2c_pxa_pio_algorithm;
 	} else {
 		i2c->adap.algo = &i2c_pxa_algorithm;
-		ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED,
-				  dev_name(&dev->dev), i2c);
+		ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler,
+				 IRQF_SHARED, dev_name(&dev->dev), i2c);
 		if (ret)
-			goto ereqirq;
+			goto emalloc;
 	}
 
 	i2c_pxa_reset(i2c);
@@ -1261,15 +1262,9 @@ static int i2c_pxa_probe(struct platform_device *dev)
 eadapt:
 	if (!i2c->use_pio)
 		free_irq(irq, i2c);
-ereqirq:
-	clk_disable_unprepare(i2c->clk);
-	iounmap(i2c->reg_base);
-eremap:
-	clk_put(i2c->clk);
-eclk:
-	kfree(i2c);
 emalloc:
 	release_mem_region(res->start, resource_size(res));
+err_nothing_to_release:
 	return ret;
 }
 
-- 
1.7.10.4

Re: [PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc

[Jingoo Han]

On Friday, July 04, 2014 5:19 AM, Rickard Strandqvist wrote:
> 
> Fix for possible null pointer dereferenc, and there is a risk
> for memory leak if something unexpected

s/dereferenc/dereference

The columns of this commit is too long.
Please keep about 80 columns.

> happens and the function returns.
> It now use Managed Device Resource instead.

s/use/uses

> 
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> ---
>  drivers/i2c/busses/i2c-pxa.c |   37 ++++++++++++++++---------------------
>  1 file changed, 16 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index be671f7..2edb633 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -1141,10 +1141,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
>  	struct resource *res = NULL;
>  	int ret, irq;
> 
> -	i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
> +	i2c = devm_kzalloc(&dev->dev, sizeof(struct pxa_i2c), GFP_KERNEL);
>  	if (!i2c) {
>  		ret = -ENOMEM;
> -		goto emalloc;
> +		goto err_nothing_to_release;
>  	}
> 
>  	/* Default adapter num to device id; i2c_pxa_probe_dt can override. */
> @@ -1154,18 +1154,19 @@ static int i2c_pxa_probe(struct platform_device *dev)
>  	if (ret > 0)
>  		ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type);
>  	if (ret < 0)
> -		goto eclk;
> +		goto err_nothing_to_release;
> 
>  	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
>  	irq = platform_get_irq(dev, 0);
>  	if (res == NULL || irq < 0) {
>  		ret = -ENODEV;
> -		goto eclk;
> +		goto err_nothing_to_release;
>  	}
> 
> -	if (!request_mem_region(res->start, resource_size(res), res->name)) {
> +	if (!devm_request_mem_region(&dev->dev, res->start,
> +				resource_size(res), res->name)) {
>  		ret = -ENOMEM;
> -		goto eclk;
> +		goto emalloc;
>  	}
> 
>  	i2c->adap.owner   = THIS_MODULE;
> @@ -1176,16 +1177,16 @@ static int i2c_pxa_probe(struct platform_device *dev)
> 
>  	strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name));
> 
> -	i2c->clk = clk_get(&dev->dev, NULL);
> +	i2c->clk = devm_clk_get(&dev->dev, NULL);
>  	if (IS_ERR(i2c->clk)) {
>  		ret = PTR_ERR(i2c->clk);
> -		goto eclk;
> +		goto emalloc;
>  	}
> 
> -	i2c->reg_base = ioremap(res->start, resource_size(res));
> -	if (!i2c->reg_base) {
> +	i2c->reg_base = devm_ioremap_resource(&adev->dev, res));
> +	if (IS_ERR(i2c->reg_base)) {
>  		ret = -EIO;
> -		goto eremap;
> +		goto emalloc;
>  	}
> 
>  	i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr;
> @@ -1227,10 +1228,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
>  		i2c->adap.algo = &i2c_pxa_pio_algorithm;
>  	} else {
>  		i2c->adap.algo = &i2c_pxa_algorithm;
> -		ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED,
> -				  dev_name(&dev->dev), i2c);
> +		ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler,
> +				 IRQF_SHARED, dev_name(&dev->dev), i2c);
>  		if (ret)
> -			goto ereqirq;
> +			goto emalloc;
>  	}
> 
>  	i2c_pxa_reset(i2c);
> @@ -1261,15 +1262,9 @@ static int i2c_pxa_probe(struct platform_device *dev)
>  eadapt:
>  	if (!i2c->use_pio)
>  		free_irq(irq, i2c);
> -ereqirq:
> -	clk_disable_unprepare(i2c->clk);
> -	iounmap(i2c->reg_base);
> -eremap:
> -	clk_put(i2c->clk);
> -eclk:
> -	kfree(i2c);
>  emalloc:
>  	release_mem_region(res->start, resource_size(res));

This function can be removed, because devm_request_mem_region()
is used. So, please remove release_mem_region().

Best regards,
Jingoo Han

> +err_nothing_to_release:
>  	return ret;
>  }
> 
> --
> 1.7.10.4

Re: [PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc

[Emil Goode]

Hello Rickard,

Since this is a probe function there is also no need to release the devm_*
resources in the i2c_pxa_remove function, this leads to double free.

Also I have a few nit-pick comments below.

On Thu, Jul 03, 2014 at 10:19:16PM +0200, Rickard Strandqvist wrote:
> Fix for possible null pointer dereferenc, and there is a risk for memory leak if something unexpected happens and the function returns.
> It now use Managed Device Resource instead.
> 
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> ---
>  drivers/i2c/busses/i2c-pxa.c |   37 ++++++++++++++++---------------------
>  1 file changed, 16 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index be671f7..2edb633 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -1141,10 +1141,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
>  	struct resource *res = NULL;
>  	int ret, irq;
>  
> -	i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
> +	i2c = devm_kzalloc(&dev->dev, sizeof(struct pxa_i2c), GFP_KERNEL);
>  	if (!i2c) {
>  		ret = -ENOMEM;
> -		goto emalloc;
> +		goto err_nothing_to_release;

Perhaps its a good idea to return directly here, then the label
err_nothing_to_release can be removed.

>  	}
>  
>  	/* Default adapter num to device id; i2c_pxa_probe_dt can override. */
> @@ -1154,18 +1154,19 @@ static int i2c_pxa_probe(struct platform_device *dev)
>  	if (ret > 0)
>  		ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type);
>  	if (ret < 0)
> -		goto eclk;
> +		goto err_nothing_to_release;

Same here.

>  
>  	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
>  	irq = platform_get_irq(dev, 0);
>  	if (res == NULL || irq < 0) {
>  		ret = -ENODEV;
> -		goto eclk;
> +		goto err_nothing_to_release;

Same here.

>  	}
>  
> -	if (!request_mem_region(res->start, resource_size(res), res->name)) {
> +	if (!devm_request_mem_region(&dev->dev, res->start,
> +				resource_size(res), res->name)) {
>  		ret = -ENOMEM;
> -		goto eclk;
> +		goto emalloc;

We could also return directly here since the release_mem_region call should
be removed, as mentioned in Jingoos reply.

>  	}
>  
>  	i2c->adap.owner   = THIS_MODULE;
> @@ -1176,16 +1177,16 @@ static int i2c_pxa_probe(struct platform_device *dev)
>  
>  	strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name));
>  
> -	i2c->clk = clk_get(&dev->dev, NULL);
> +	i2c->clk = devm_clk_get(&dev->dev, NULL);
>  	if (IS_ERR(i2c->clk)) {
>  		ret = PTR_ERR(i2c->clk);
> -		goto eclk;
> +		goto emalloc;

Same here.

>  	}
>  
> -	i2c->reg_base = ioremap(res->start, resource_size(res));
> -	if (!i2c->reg_base) {
> +	i2c->reg_base = devm_ioremap_resource(&adev->dev, res));
> +	if (IS_ERR(i2c->reg_base)) {
>  		ret = -EIO;
> -		goto eremap;
> +		goto emalloc;

Same here.

>  	}
>  
>  	i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr;
> @@ -1227,10 +1228,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
>  		i2c->adap.algo = &i2c_pxa_pio_algorithm;
>  	} else {
>  		i2c->adap.algo = &i2c_pxa_algorithm;
> -		ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED,
> -				  dev_name(&dev->dev), i2c);
> +		ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler,
> +				 IRQF_SHARED, dev_name(&dev->dev), i2c);
>  		if (ret)
> -			goto ereqirq;
> +			goto emalloc;

Same here.

>  	}
>  
>  	i2c_pxa_reset(i2c);
> @@ -1261,15 +1262,9 @@ static int i2c_pxa_probe(struct platform_device *dev)
>  eadapt:
>  	if (!i2c->use_pio)
>  		free_irq(irq, i2c);

The free_irq() call should also be removed since devm_request_irq() was used.

> -ereqirq:
> -	clk_disable_unprepare(i2c->clk);
> -	iounmap(i2c->reg_base);
> -eremap:
> -	clk_put(i2c->clk);
> -eclk:
> -	kfree(i2c);
>  emalloc:
>  	release_mem_region(res->start, resource_size(res));
> +err_nothing_to_release:
>  	return ret;
>  }
>

Best regards,

Emil Goode

Re: [PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc

[Rickard Strandqvist]

2014-07-04 11:10 GMT+02:00 Emil Goode <emilgoode@gmail.com>:
> Hello Rickard,
>
> Since this is a probe function there is also no need to release the devm_*
> resources in the i2c_pxa_remove function, this leads to double free.
>
> Also I have a few nit-pick comments below.
>
> On Thu, Jul 03, 2014 at 10:19:16PM +0200, Rickard Strandqvist wrote:
>> Fix for possible null pointer dereferenc, and there is a risk for memory leak if something unexpected happens and the function returns.
>> It now use Managed Device Resource instead.
>>
>> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
>> ---
>>  drivers/i2c/busses/i2c-pxa.c |   37 ++++++++++++++++---------------------
>>  1 file changed, 16 insertions(+), 21 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
>> index be671f7..2edb633 100644
>> --- a/drivers/i2c/busses/i2c-pxa.c
>> +++ b/drivers/i2c/busses/i2c-pxa.c
>> @@ -1141,10 +1141,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
>>       struct resource *res = NULL;
>>       int ret, irq;
>>
>> -     i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
>> +     i2c = devm_kzalloc(&dev->dev, sizeof(struct pxa_i2c), GFP_KERNEL);
>>       if (!i2c) {
>>               ret = -ENOMEM;
>> -             goto emalloc;
>> +             goto err_nothing_to_release;
>
> Perhaps its a good idea to return directly here, then the label
> err_nothing_to_release can be removed.
>
>>       }
>>
>>       /* Default adapter num to device id; i2c_pxa_probe_dt can override. */
>> @@ -1154,18 +1154,19 @@ static int i2c_pxa_probe(struct platform_device *dev)
>>       if (ret > 0)
>>               ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type);
>>       if (ret < 0)
>> -             goto eclk;
>> +             goto err_nothing_to_release;
>
> Same here.
>
>>
>>       res = platform_get_resource(dev, IORESOURCE_MEM, 0);
>>       irq = platform_get_irq(dev, 0);
>>       if (res == NULL || irq < 0) {
>>               ret = -ENODEV;
>> -             goto eclk;
>> +             goto err_nothing_to_release;
>
> Same here.
>
>>       }
>>
>> -     if (!request_mem_region(res->start, resource_size(res), res->name)) {
>> +     if (!devm_request_mem_region(&dev->dev, res->start,
>> +                             resource_size(res), res->name)) {
>>               ret = -ENOMEM;
>> -             goto eclk;
>> +             goto emalloc;
>
> We could also return directly here since the release_mem_region call should
> be removed, as mentioned in Jingoos reply.
>
>>       }
>>
>>       i2c->adap.owner   = THIS_MODULE;
>> @@ -1176,16 +1177,16 @@ static int i2c_pxa_probe(struct platform_device *dev)
>>
>>       strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name));
>>
>> -     i2c->clk = clk_get(&dev->dev, NULL);
>> +     i2c->clk = devm_clk_get(&dev->dev, NULL);
>>       if (IS_ERR(i2c->clk)) {
>>               ret = PTR_ERR(i2c->clk);
>> -             goto eclk;
>> +             goto emalloc;
>
> Same here.
>
>>       }
>>
>> -     i2c->reg_base = ioremap(res->start, resource_size(res));
>> -     if (!i2c->reg_base) {
>> +     i2c->reg_base = devm_ioremap_resource(&adev->dev, res));
>> +     if (IS_ERR(i2c->reg_base)) {
>>               ret = -EIO;
>> -             goto eremap;
>> +             goto emalloc;
>
> Same here.
>
>>       }
>>
>>       i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr;
>> @@ -1227,10 +1228,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
>>               i2c->adap.algo = &i2c_pxa_pio_algorithm;
>>       } else {
>>               i2c->adap.algo = &i2c_pxa_algorithm;
>> -             ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED,
>> -                               dev_name(&dev->dev), i2c);
>> +             ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler,
>> +                              IRQF_SHARED, dev_name(&dev->dev), i2c);
>>               if (ret)
>> -                     goto ereqirq;
>> +                     goto emalloc;
>
> Same here.
>
>>       }
>>
>>       i2c_pxa_reset(i2c);
>> @@ -1261,15 +1262,9 @@ static int i2c_pxa_probe(struct platform_device *dev)
>>  eadapt:
>>       if (!i2c->use_pio)
>>               free_irq(irq, i2c);
>
> The free_irq() call should also be removed since devm_request_irq() was used.
>
>> -ereqirq:
>> -     clk_disable_unprepare(i2c->clk);
>> -     iounmap(i2c->reg_base);
>> -eremap:
>> -     clk_put(i2c->clk);
>> -eclk:
>> -     kfree(i2c);
>>  emalloc:
>>       release_mem_region(res->start, resource_size(res));
>> +err_nothing_to_release:
>>       return ret;
>>  }
>>
>
> Best regards,
>
> Emil Goode

Hi All!

Ok, so there is literally nothing to do release anymore.
A good system Devres, I understand you want everyone to use it.

I also think it is also better to return directly then.
But who decides, Wolfram?

Would appreciate if I did not have to do more than one patch more.

And thanks Jingoo for spelling, etc.


Kind regards
Rickard Strandqvist

Re: [PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc

[Emil Goode]

Hello,

I noticed one more thing.

On Fri, Jul 04, 2014 at 07:07:48PM +0200, Rickard Strandqvist wrote:
> 2014-07-04 11:10 GMT+02:00 Emil Goode <emilgoode@gmail.com>:
> > Hello Rickard,
> >
> > Since this is a probe function there is also no need to release the devm_*
> > resources in the i2c_pxa_remove function, this leads to double free.
> >
> > Also I have a few nit-pick comments below.
> >
> > On Thu, Jul 03, 2014 at 10:19:16PM +0200, Rickard Strandqvist wrote:
> >> Fix for possible null pointer dereferenc, and there is a risk for memory leak if something unexpected happens and the function returns.
> >> It now use Managed Device Resource instead.
> >>
> >> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> >> ---
> >>  drivers/i2c/busses/i2c-pxa.c |   37 ++++++++++++++++---------------------
> >>  1 file changed, 16 insertions(+), 21 deletions(-)
> >>
> >> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> >> index be671f7..2edb633 100644
> >> --- a/drivers/i2c/busses/i2c-pxa.c
> >> +++ b/drivers/i2c/busses/i2c-pxa.c
> >> @@ -1141,10 +1141,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
> >>       struct resource *res = NULL;
> >>       int ret, irq;
> >>
> >> -     i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
> >> +     i2c = devm_kzalloc(&dev->dev, sizeof(struct pxa_i2c), GFP_KERNEL);
> >>       if (!i2c) {
> >>               ret = -ENOMEM;
> >> -             goto emalloc;
> >> +             goto err_nothing_to_release;
> >
> > Perhaps its a good idea to return directly here, then the label
> > err_nothing_to_release can be removed.
> >
> >>       }
> >>
> >>       /* Default adapter num to device id; i2c_pxa_probe_dt can override. */
> >> @@ -1154,18 +1154,19 @@ static int i2c_pxa_probe(struct platform_device *dev)
> >>       if (ret > 0)
> >>               ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type);
> >>       if (ret < 0)
> >> -             goto eclk;
> >> +             goto err_nothing_to_release;
> >
> > Same here.
> >
> >>
> >>       res = platform_get_resource(dev, IORESOURCE_MEM, 0);
> >>       irq = platform_get_irq(dev, 0);
> >>       if (res == NULL || irq < 0) {
> >>               ret = -ENODEV;
> >> -             goto eclk;
> >> +             goto err_nothing_to_release;
> >
> > Same here.
> >
> >>       }
> >>
> >> -     if (!request_mem_region(res->start, resource_size(res), res->name)) {
> >> +     if (!devm_request_mem_region(&dev->dev, res->start,
> >> +                             resource_size(res), res->name)) {
> >>               ret = -ENOMEM;
> >> -             goto eclk;
> >> +             goto emalloc;
> >
> > We could also return directly here since the release_mem_region call should
> > be removed, as mentioned in Jingoos reply.
> >
> >>       }
> >>
> >>       i2c->adap.owner   = THIS_MODULE;
> >> @@ -1176,16 +1177,16 @@ static int i2c_pxa_probe(struct platform_device *dev)
> >>
> >>       strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name));
> >>
> >> -     i2c->clk = clk_get(&dev->dev, NULL);
> >> +     i2c->clk = devm_clk_get(&dev->dev, NULL);
> >>       if (IS_ERR(i2c->clk)) {
> >>               ret = PTR_ERR(i2c->clk);
> >> -             goto eclk;
> >> +             goto emalloc;
> >
> > Same here.
> >
> >>       }
> >>
> >> -     i2c->reg_base = ioremap(res->start, resource_size(res));
> >> -     if (!i2c->reg_base) {
> >> +     i2c->reg_base = devm_ioremap_resource(&adev->dev, res));
> >> +     if (IS_ERR(i2c->reg_base)) {
> >>               ret = -EIO;
> >> -             goto eremap;
> >> +             goto emalloc;
> >
> > Same here.
> >
> >>       }
> >>
> >>       i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr;
> >> @@ -1227,10 +1228,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
> >>               i2c->adap.algo = &i2c_pxa_pio_algorithm;
> >>       } else {
> >>               i2c->adap.algo = &i2c_pxa_algorithm;
> >> -             ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED,
> >> -                               dev_name(&dev->dev), i2c);
> >> +             ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler,
> >> +                              IRQF_SHARED, dev_name(&dev->dev), i2c);
> >>               if (ret)
> >> -                     goto ereqirq;
> >> +                     goto emalloc;
> >
> > Same here.
> >
> >>       }
> >>
> >>       i2c_pxa_reset(i2c);
> >> @@ -1261,15 +1262,9 @@ static int i2c_pxa_probe(struct platform_device *dev)
> >>  eadapt:
> >>       if (!i2c->use_pio)
> >>               free_irq(irq, i2c);
> >
> > The free_irq() call should also be removed since devm_request_irq() was used.
> >
> >> -ereqirq:
> >> -     clk_disable_unprepare(i2c->clk);

I think we should keep the clk_disable_unprepare() call.

> >> -     iounmap(i2c->reg_base);
> >> -eremap:
> >> -     clk_put(i2c->clk);
> >> -eclk:
> >> -     kfree(i2c);
> >>  emalloc:
> >>       release_mem_region(res->start, resource_size(res));
> >> +err_nothing_to_release:
> >>       return ret;
> >>  }
> >>
> >
> > Best regards,
> >
> > Emil Goode
> 
> Hi All!
> 
> Ok, so there is literally nothing to do release anymore.
> A good system Devres, I understand you want everyone to use it.
> 
> I also think it is also better to return directly then.
> But who decides, Wolfram?

Yes, Wolfram is the maintainer.

Personally I would do the devm_* convertion in a second patch.

Best regards,

Emil Goode

Re: [PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc

[Rickard Strandqvist]

2014-07-04 19:24 GMT+02:00 Emil Goode <emilgoode@gmail.com>:
> Hello,
>
> I noticed one more thing.
>
> On Fri, Jul 04, 2014 at 07:07:48PM +0200, Rickard Strandqvist wrote:
>> 2014-07-04 11:10 GMT+02:00 Emil Goode <emilgoode@gmail.com>:
>> > Hello Rickard,
>> >
>> > Since this is a probe function there is also no need to release the devm_*
>> > resources in the i2c_pxa_remove function, this leads to double free.
>> >
>> > Also I have a few nit-pick comments below.
>> >
>> > On Thu, Jul 03, 2014 at 10:19:16PM +0200, Rickard Strandqvist wrote:
>> >> Fix for possible null pointer dereferenc, and there is a risk for memory leak if something unexpected happens and the function returns.
>> >> It now use Managed Device Resource instead.
>> >>
>> >> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
>> >> ---
>> >>  drivers/i2c/busses/i2c-pxa.c |   37 ++++++++++++++++---------------------
>> >>  1 file changed, 16 insertions(+), 21 deletions(-)
>> >>
>> >> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
>> >> index be671f7..2edb633 100644
>> >> --- a/drivers/i2c/busses/i2c-pxa.c
>> >> +++ b/drivers/i2c/busses/i2c-pxa.c
>> >> @@ -1141,10 +1141,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
>> >>       struct resource *res = NULL;
>> >>       int ret, irq;
>> >>
>> >> -     i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
>> >> +     i2c = devm_kzalloc(&dev->dev, sizeof(struct pxa_i2c), GFP_KERNEL);
>> >>       if (!i2c) {
>> >>               ret = -ENOMEM;
>> >> -             goto emalloc;
>> >> +             goto err_nothing_to_release;
>> >
>> > Perhaps its a good idea to return directly here, then the label
>> > err_nothing_to_release can be removed.
>> >
>> >>       }
>> >>
>> >>       /* Default adapter num to device id; i2c_pxa_probe_dt can override. */
>> >> @@ -1154,18 +1154,19 @@ static int i2c_pxa_probe(struct platform_device *dev)
>> >>       if (ret > 0)
>> >>               ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type);
>> >>       if (ret < 0)
>> >> -             goto eclk;
>> >> +             goto err_nothing_to_release;
>> >
>> > Same here.
>> >
>> >>
>> >>       res = platform_get_resource(dev, IORESOURCE_MEM, 0);
>> >>       irq = platform_get_irq(dev, 0);
>> >>       if (res == NULL || irq < 0) {
>> >>               ret = -ENODEV;
>> >> -             goto eclk;
>> >> +             goto err_nothing_to_release;
>> >
>> > Same here.
>> >
>> >>       }
>> >>
>> >> -     if (!request_mem_region(res->start, resource_size(res), res->name)) {
>> >> +     if (!devm_request_mem_region(&dev->dev, res->start,
>> >> +                             resource_size(res), res->name)) {
>> >>               ret = -ENOMEM;
>> >> -             goto eclk;
>> >> +             goto emalloc;
>> >
>> > We could also return directly here since the release_mem_region call should
>> > be removed, as mentioned in Jingoos reply.
>> >
>> >>       }
>> >>
>> >>       i2c->adap.owner   = THIS_MODULE;
>> >> @@ -1176,16 +1177,16 @@ static int i2c_pxa_probe(struct platform_device *dev)
>> >>
>> >>       strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name));
>> >>
>> >> -     i2c->clk = clk_get(&dev->dev, NULL);
>> >> +     i2c->clk = devm_clk_get(&dev->dev, NULL);
>> >>       if (IS_ERR(i2c->clk)) {
>> >>               ret = PTR_ERR(i2c->clk);
>> >> -             goto eclk;
>> >> +             goto emalloc;
>> >
>> > Same here.
>> >
>> >>       }
>> >>
>> >> -     i2c->reg_base = ioremap(res->start, resource_size(res));
>> >> -     if (!i2c->reg_base) {
>> >> +     i2c->reg_base = devm_ioremap_resource(&adev->dev, res));
>> >> +     if (IS_ERR(i2c->reg_base)) {
>> >>               ret = -EIO;
>> >> -             goto eremap;
>> >> +             goto emalloc;
>> >
>> > Same here.
>> >
>> >>       }
>> >>
>> >>       i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr;
>> >> @@ -1227,10 +1228,10 @@ static int i2c_pxa_probe(struct platform_device *dev)
>> >>               i2c->adap.algo = &i2c_pxa_pio_algorithm;
>> >>       } else {
>> >>               i2c->adap.algo = &i2c_pxa_algorithm;
>> >> -             ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED,
>> >> -                               dev_name(&dev->dev), i2c);
>> >> +             ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler,
>> >> +                              IRQF_SHARED, dev_name(&dev->dev), i2c);
>> >>               if (ret)
>> >> -                     goto ereqirq;
>> >> +                     goto emalloc;
>> >
>> > Same here.
>> >
>> >>       }
>> >>
>> >>       i2c_pxa_reset(i2c);
>> >> @@ -1261,15 +1262,9 @@ static int i2c_pxa_probe(struct platform_device *dev)
>> >>  eadapt:
>> >>       if (!i2c->use_pio)
>> >>               free_irq(irq, i2c);
>> >
>> > The free_irq() call should also be removed since devm_request_irq() was used.
>> >
>> >> -ereqirq:
>> >> -     clk_disable_unprepare(i2c->clk);
>
> I think we should keep the clk_disable_unprepare() call.
>
>> >> -     iounmap(i2c->reg_base);
>> >> -eremap:
>> >> -     clk_put(i2c->clk);
>> >> -eclk:
>> >> -     kfree(i2c);
>> >>  emalloc:
>> >>       release_mem_region(res->start, resource_size(res));
>> >> +err_nothing_to_release:
>> >>       return ret;
>> >>  }
>> >>
>> >
>> > Best regards,
>> >
>> > Emil Goode
>>
>> Hi All!
>>
>> Ok, so there is literally nothing to do release anymore.
>> A good system Devres, I understand you want everyone to use it.
>>
>> I also think it is also better to return directly then.
>> But who decides, Wolfram?
>
> Yes, Wolfram is the maintainer.
>
> Personally I would do the devm_* convertion in a second patch.

Hi

Ok then, Wolfram!

Keep only:

ereqirq:
     clk_disable_unprepare(i2c->clk);

And let everyone else just return?


And Emil, as I said before, it would in that case the first patch just be:
 emalloc:
-       release_mem_region(res->start, resource_size(res));
+       if(res)
+               release_mem_region(res->start, resource_size(res));

It is rather pointless to add something in a patch, to remove it in the next.



Kind regards
Rickard Strandqvist

Re: [PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc

[Wolfram Sang]

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> Ok then, Wolfram!
> 
> Keep only:
> 
> ereqirq:
>      clk_disable_unprepare(i2c->clk);
> 
> And let everyone else just return?

I haven't looked at the details, but when you simply can return, do it.

> It is rather pointless to add something in a patch, to remove it in the next.

Yup, just say in the patch description that it fixes this bug.


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