[PATCH v1 1/1] i2c: robotfuzz-osif: Propagate parent device to I2C core

[PATCH v1 1/1] i2c: robotfuzz-osif: Propagate parent device to I2C core

[Andy Shevchenko]

I2C core might use parent device to retrieve properties of
the controller. Propagate parent device for that.

Fixes: 83e53a8f120f ("i2c: Add bus driver for for OSIF USB i2c device.")
Reported-by: syzbot+0591ccf54ee05344e4eb@syzkaller.appspotmail.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/i2c/busses/i2c-robotfuzz-osif.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/i2c/busses/i2c-robotfuzz-osif.c b/drivers/i2c/busses/i2c-robotfuzz-osif.c
index 66dfa211e736..bfbfa0d07bb2 100644
--- a/drivers/i2c/busses/i2c-robotfuzz-osif.c
+++ b/drivers/i2c/busses/i2c-robotfuzz-osif.c
@@ -128,6 +128,7 @@ MODULE_DEVICE_TABLE(usb, osif_table);
 static int osif_probe(struct usb_interface *interface,
 			     const struct usb_device_id *id)
 {
+	struct device *dev = &interface->dev;
 	int ret;
 	struct osif_priv *priv;
 	u16 version;
@@ -145,6 +146,7 @@ static int osif_probe(struct usb_interface *interface,
 	priv->adapter.class = I2C_CLASS_HWMON;
 	priv->adapter.algo = &osif_algorithm;
 	priv->adapter.algo_data = priv;
+	priv->adapter.dev.parent = dev;
 	snprintf(priv->adapter.name, sizeof(priv->adapter.name),
 		 "OSIF at bus %03d device %03d",
 		 priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
-- 
2.34.1

Re: [PATCH v1 1/1] i2c: robotfuzz-osif: Propagate parent device to I2C core

[Wolfram Sang]

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> +	struct device *dev = &interface->dev;

This now creates a mixture of 'dev' and '&interface->dev'...

> +	priv->adapter.dev.parent = dev;

I propose to use &interface->dev here in this patch and convert to dev
in a later patch?


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Re: [PATCH v1 1/1] i2c: robotfuzz-osif: Propagate parent device to I2C core

[Andy Shevchenko]

On Fri, Feb 18, 2022 at 03:22:19PM +0100, Wolfram Sang wrote:
> 
> > +	struct device *dev = &interface->dev;
> 
> This now creates a mixture of 'dev' and '&interface->dev'...
> 
> > +	priv->adapter.dev.parent = dev;
> 
> I propose to use &interface->dev here in this patch and convert to dev
> in a later patch?

Why not?
Will do for next version (next week).

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v1 1/1] i2c: robotfuzz-osif: Propagate parent device to I2C core

[Johan Hovold]

On Fri, Feb 04, 2022 at 05:17:26PM +0200, Andy Shevchenko wrote:
> I2C core might use parent device to retrieve properties of
> the controller. Propagate parent device for that.

What is the problem you're trying to solve here?

If you've changed some core function so that the kernel crashes because
of this, you need to address this in core.

Looks like you're also changing the device topology with this change.

This needs more details.

> Fixes: 83e53a8f120f ("i2c: Add bus driver for for OSIF USB i2c device.")

This isn't the commit causing the NULL deref.

> Reported-by: syzbot+0591ccf54ee05344e4eb@syzkaller.appspotmail.com
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/i2c/busses/i2c-robotfuzz-osif.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-robotfuzz-osif.c b/drivers/i2c/busses/i2c-robotfuzz-osif.c
> index 66dfa211e736..bfbfa0d07bb2 100644
> --- a/drivers/i2c/busses/i2c-robotfuzz-osif.c
> +++ b/drivers/i2c/busses/i2c-robotfuzz-osif.c
> @@ -128,6 +128,7 @@ MODULE_DEVICE_TABLE(usb, osif_table);
>  static int osif_probe(struct usb_interface *interface,
>  			     const struct usb_device_id *id)
>  {
> +	struct device *dev = &interface->dev;
>  	int ret;
>  	struct osif_priv *priv;
>  	u16 version;
> @@ -145,6 +146,7 @@ static int osif_probe(struct usb_interface *interface,
>  	priv->adapter.class = I2C_CLASS_HWMON;
>  	priv->adapter.algo = &osif_algorithm;
>  	priv->adapter.algo_data = priv;
> +	priv->adapter.dev.parent = dev;
>  	snprintf(priv->adapter.name, sizeof(priv->adapter.name),
>  		 "OSIF at bus %03d device %03d",
>  		 priv->usb_dev->bus->busnum, priv->usb_dev->devnum);

Johan

Re: [PATCH v1 1/1] i2c: robotfuzz-osif: Propagate parent device to I2C core

[Andy Shevchenko]

On Mon, Feb 21, 2022 at 10:56:20AM +0100, Johan Hovold wrote:
> On Fri, Feb 04, 2022 at 05:17:26PM +0200, Andy Shevchenko wrote:
> > I2C core might use parent device to retrieve properties of
> > the controller. Propagate parent device for that.
> 
> What is the problem you're trying to solve here?

Okay, let's drop the patch.

-- 
With Best Regards,
Andy Shevchenko