Re: [PATCH 2/4] eisa: call put_device if device_register fails

Re: [PATCH 2/4] eisa: call put_device if device_register fails

[Bjorn Helgaas]

On Fri, Dec 13, 2013 at 07:39:54PM +0100, Levente Kurusa wrote:
> We need to give up the last reference to edev->dev, so
> we need to call put_device().
> 
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Levente Kurusa <levex@linux.com>

I applied this and will push it through my PCI tree, since I don't think
anybody really takes care of EISA these days.

I looked at other callers of device_register(), and most of them look like
they have the same problem.  Can you fix the others, too?  This patch says
"2/4", so maybe you already are, but I can't find the other patches in the
series.

Bjorn

> ---
>  drivers/eisa/eisa-bus.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/eisa/eisa-bus.c b/drivers/eisa/eisa-bus.c
> index 272a3ec..8842cde 100644
> --- a/drivers/eisa/eisa-bus.c
> +++ b/drivers/eisa/eisa-bus.c
> @@ -232,8 +232,10 @@ static int __init eisa_init_device(struct eisa_root_device *root,
>  static int __init eisa_register_device(struct eisa_device *edev)
>  {
>  	int rc = device_register(&edev->dev);
> -	if (rc)
> +	if (rc) {
> +		put_device(&edev->dev);
>  		return rc;
> +	}
>  
>  	rc = device_create_file(&edev->dev, &dev_attr_signature);
>  	if (rc)
> -- 
> 1.8.3.1
> 

Re: [PATCH 2/4] eisa: call put_device if device_register fails

[Levente Kurusa]

On 12/13/2013 08:04 PM, Bjorn Helgaas wrote:
> On Fri, Dec 13, 2013 at 07:39:54PM +0100, Levente Kurusa wrote:
>> We need to give up the last reference to edev->dev, so
>> we need to call put_device().
>>
>> Cc: Bjorn Helgaas <bhelgaas@google.com>
>> Signed-off-by: Levente Kurusa <levex@linux.com>
> 
> I applied this and will push it through my PCI tree, since I don't think
> anybody really takes care of EISA these days.
> 
> I looked at other callers of device_register(), and most of them look like
> they have the same problem.  Can you fix the others, too?  This patch says
> "2/4", so maybe you already are, but I can't find the other patches in the
> series.

Yes, the patchset didn't hit LKML due to me being a noob with git-send-email. :-(

I will fix them, just sent this to verify that I am doing it right. :-)

Thanks for applying!

-- 
Regards,
Levente Kurusa

Re: [PATCH 1/4] net: phy: call put_device on device_register() failure

[Greg Kroah-Hartman]

On Fri, Dec 13, 2013 at 07:39:53PM +0100, Levente Kurusa wrote:
> It is required to call put_device() if device_register() fails,
> so that we give up the last reference to the device. Calling put_device
> allows for mdiobus_release to be executed, kfreeing the bus.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> Signed-off-by: Levente Kurusa <levex@linux.com>

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH 3/4] backlight: lcd: call put_device if device_register fails

[Jingoo Han]

On Saturday, December 14, 2013 3:40 AM, Levente Kurusa wrote:
> 
> Currently we kfree the container of the device which failed to register.
> This is wrong as the last reference is not given up with a put_device
> call. Also, now that we have put_device() callen, we no longer need
> the kfree as the new_ld->dev.release function will take care of kfreeing
> the associated memory.
> 
> Signed-off-by: Levente Kurusa <levex@linux.com>

(+cc Andrew Morton)

Acked-by: Jingoo Han <jg1.han@samsung.com>

It looks good.
According to the comment of device_register, put_device()
should be used, instead of directly freeing.

./drivers/base/core.c

 * NOTE: _Never_ directly free @dev after calling this function, even
 * if it returned an error! Always use put_device() to give up the
 * reference initialized in this function instead.
 */
int device_register(struct device *dev)
{
        device_initialize(dev);
        return device_add(dev);
}
EXPORT_SYMBOL_GPL(device_register);

Levente Kurusa,
By the way, don't send the same mails three times, without any
reason. It is the waste of traffic. :-(

Best regards,
Jingoo Han

> ---
>  drivers/video/backlight/lcd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
> index 93cf15e..7de847d 100644
> --- a/drivers/video/backlight/lcd.c
> +++ b/drivers/video/backlight/lcd.c
> @@ -228,7 +228,7 @@ struct lcd_device *lcd_device_register(const char *name, struct device *parent,
> 
>  	rc = device_register(&new_ld->dev);
>  	if (rc) {
> -		kfree(new_ld);
> +		put_device(&new_ld->dev);
>  		return ERR_PTR(rc);
>  	}
> 
> --
> 1.8.3.1

Re: [PATCH 3/4] backlight: lcd: call put_device if device_register fails

[Jingoo Han]

On Saturday, December 14, 2013 3:40 AM, Levente Kurusa wrote:
> 
> Currently we kfree the container of the device which failed to register.
> This is wrong as the last reference is not given up with a put_device
> call. Also, now that we have put_device() callen, we no longer need
> the kfree as the new_ld->dev.release function will take care of kfreeing
> the associated memory.
> 
> Signed-off-by: Levente Kurusa <levex@linux.com>

(+cc Andrew Morton)

Acked-by: Jingoo Han <jg1.han@samsung.com>

It looks good.
According to the comment of device_register, put_device()
should be used, instead of directly freeing.

./drivers/base/core.c

 * NOTE: _Never_ directly free @dev after calling this function, even
 * if it returned an error! Always use put_device() to give up the
 * reference initialized in this function instead.
 */
int device_register(struct device *dev)
{
        device_initialize(dev);
        return device_add(dev);
}
EXPORT_SYMBOL_GPL(device_register);

Levente Kurusa,
By the way, don't send the same mails three times, without any
reason. It is the waste of traffic. :-(

Best regards,
Jingoo Han

> ---
>  drivers/video/backlight/lcd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
> index 93cf15e..7de847d 100644
> --- a/drivers/video/backlight/lcd.c
> +++ b/drivers/video/backlight/lcd.c
> @@ -228,7 +228,7 @@ struct lcd_device *lcd_device_register(const char *name, struct device *parent,
> 
>  	rc = device_register(&new_ld->dev);
>  	if (rc) {
> -		kfree(new_ld);
> +		put_device(&new_ld->dev);
>  		return ERR_PTR(rc);
>  	}
> 
> --
> 1.8.3.1

Re: [PATCH 3/4] backlight: lcd: call put_device if device_register fails

[Levente Kurusa]

On 12/16/2013 05:52 AM, Jingoo Han wrote:
> On Saturday, December 14, 2013 3:40 AM, Levente Kurusa wrote:
>>
>> Currently we kfree the container of the device which failed to register.
>> This is wrong as the last reference is not given up with a put_device
>> call. Also, now that we have put_device() callen, we no longer need
>> the kfree as the new_ld->dev.release function will take care of kfreeing
>> the associated memory.
>>
>> Signed-off-by: Levente Kurusa <levex@linux.com>
> 
> (+cc Andrew Morton)
> 
> Acked-by: Jingoo Han <jg1.han@samsung.com>
> 
> It looks good.
> According to the comment of device_register, put_device()
> should be used, instead of directly freeing.
Indeed, this is also mostly explained in [0/4]. Thanks for the Ack!
> 
[...]
> 
> Levente Kurusa,
> By the way, don't send the same mails three times, without any
> reason. It is the waste of traffic. :-(
> 

Yea, sorry about that I messed up my git's smtp config and hence most of the
messages bounced off. It didn't even reach LKML. Sorry once more.


-- 
Regards,
Levente Kurusa

Re: [PATCH 3/4] backlight: lcd: call put_device if device_register fails

[Levente Kurusa]

On 12/16/2013 05:52 AM, Jingoo Han wrote:
> On Saturday, December 14, 2013 3:40 AM, Levente Kurusa wrote:
>>
>> Currently we kfree the container of the device which failed to register.
>> This is wrong as the last reference is not given up with a put_device
>> call. Also, now that we have put_device() callen, we no longer need
>> the kfree as the new_ld->dev.release function will take care of kfreeing
>> the associated memory.
>>
>> Signed-off-by: Levente Kurusa <levex@linux.com>
> 
> (+cc Andrew Morton)
> 
> Acked-by: Jingoo Han <jg1.han@samsung.com>
> 
> It looks good.
> According to the comment of device_register, put_device()
> should be used, instead of directly freeing.
Indeed, this is also mostly explained in [0/4]. Thanks for the Ack!
> 
[...]
> 
> Levente Kurusa,
> By the way, don't send the same mails three times, without any
> reason. It is the waste of traffic. :-(
> 

Yea, sorry about that I messed up my git's smtp config and hence most of the
messages bounced off. It didn't even reach LKML. Sorry once more.


-- 
Regards,
Levente Kurusa

Re: [PATCH 3/4] backlight: lcd: call put_device if device_register fails

[Jingoo Han]

On Saturday, December 14, 2013 3:40 AM, Levente Kurusa wrote:
> 
> Currently we kfree the container of the device which failed to register.
> This is wrong as the last reference is not given up with a put_device
> call. Also, now that we have put_device() callen, we no longer need
> the kfree as the new_ld->dev.release function will take care of kfreeing
> the associated memory.
> 
> Signed-off-by: Levente Kurusa <levex@linux.com>
> ---
>  drivers/video/backlight/lcd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
> index 93cf15e..7de847d 100644
> --- a/drivers/video/backlight/lcd.c
> +++ b/drivers/video/backlight/lcd.c
> @@ -228,7 +228,7 @@ struct lcd_device *lcd_device_register(const char *name, struct device *parent,
> 
>  	rc = device_register(&new_ld->dev);
>  	if (rc) {
> -		kfree(new_ld);
> +		put_device(&new_ld->dev);
>  		return ERR_PTR(rc);
>  	}

(+cc Andrew Morton)

Hi Levente Kurusa,

Would you fix the same thing for 'backlight.c' file?

./drivers/video/backlight/backlight.c
struct backlight_device *backlight_device_register(const char *name,
    .....
    rc = device_register(&new_bd->dev);
            if (rc) {
                    kfree(new_bd);
                    return ERR_PTR(rc);
            }

Best regards,
Jingoo Han

Re: [PATCH 3/4] backlight: lcd: call put_device if device_register fails

[Jingoo Han]

On Saturday, December 14, 2013 3:40 AM, Levente Kurusa wrote:
> 
> Currently we kfree the container of the device which failed to register.
> This is wrong as the last reference is not given up with a put_device
> call. Also, now that we have put_device() callen, we no longer need
> the kfree as the new_ld->dev.release function will take care of kfreeing
> the associated memory.
> 
> Signed-off-by: Levente Kurusa <levex@linux.com>
> ---
>  drivers/video/backlight/lcd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
> index 93cf15e..7de847d 100644
> --- a/drivers/video/backlight/lcd.c
> +++ b/drivers/video/backlight/lcd.c
> @@ -228,7 +228,7 @@ struct lcd_device *lcd_device_register(const char *name, struct device *parent,
> 
>  	rc = device_register(&new_ld->dev);
>  	if (rc) {
> -		kfree(new_ld);
> +		put_device(&new_ld->dev);
>  		return ERR_PTR(rc);
>  	}

(+cc Andrew Morton)

Hi Levente Kurusa,

Would you fix the same thing for 'backlight.c' file?

./drivers/video/backlight/backlight.c
struct backlight_device *backlight_device_register(const char *name,
    .....
    rc = device_register(&new_bd->dev);
            if (rc) {
                    kfree(new_bd);
                    return ERR_PTR(rc);
            }

Best regards,
Jingoo Han

[PATCH 2/4] eisa: call put_device if device_register fails

[Levente Kurusa]

We need to give up the last reference to edev->dev, so
we need to call put_device().

Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Levente Kurusa <levex@linux.com>
---
 drivers/eisa/eisa-bus.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/eisa/eisa-bus.c b/drivers/eisa/eisa-bus.c
index 272a3ec..8842cde 100644
--- a/drivers/eisa/eisa-bus.c
+++ b/drivers/eisa/eisa-bus.c
@@ -232,8 +232,10 @@ static int __init eisa_init_device(struct eisa_root_device *root,
 static int __init eisa_register_device(struct eisa_device *edev)
 {
 	int rc = device_register(&edev->dev);
-	if (rc)
+	if (rc) {
+		put_device(&edev->dev);
 		return rc;
+	}
 
 	rc = device_create_file(&edev->dev, &dev_attr_signature);
 	if (rc)
-- 
1.8.3.1