Re: [patch 25/28] USB: cdc-acm: fix sysfs attribute registration bug

On Thu, 23 Aug 2007, Greg KH wrote:

> -stable review patch.  If anyone has any objections, please let us know.
> 
> ------------------
> 
> From: Alan Stern <[email protected]>
> 
> This patch (as950) fixes a bug in the cdc-acm driver.  It doesn't keep
> track of which interface (control or data) the sysfs attributes get
> registered for, and as a result, during disconnect it will sometimes
> attempt to remove the attributes from the wrong interface.  The
> left-over attributes can cause a crash later on, particularly if the driver
> module has been unloaded.
> 
> Signed-off-by: Alan Stern <[email protected]>
> Acked-by: Oliver Neukum <[email protected]>
> Signed-off-by: Greg Kroah-Hartman <[email protected]>
> 
> ---
>  drivers/usb/class/cdc-acm.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 
> --- a/drivers/usb/class/cdc-acm.c
> +++ b/drivers/usb/class/cdc-acm.c
> @@ -900,6 +900,10 @@ next_desc:
>  			return -ENODEV;
>  		}
>  	}
> +
> +	/* Accept probe requests only for the control interface */
> +	if (intf != control_interface)
> +		return -ENODEV;
>  	
>  	if (data_interface_num != call_interface_num)
>  		dev_dbg(&intf->dev,"Seperate call control interface. That is not fully supported.");
> 

Odd.  This doesn't include the entire patch; the second hunk is
missing.  It should go on to say:

@@ -1109,10 +1113,12 @@ static void acm_disconnect(struct usb_interface *intf)
 		return;
 	}
 	if (acm->country_codes){
-		device_remove_file(&intf->dev, &dev_attr_wCountryCodes);
-		device_remove_file(&intf->dev, &dev_attr_iCountryCodeRelDate);
+		device_remove_file(&acm->control->dev,
+				&dev_attr_wCountryCodes);
+		device_remove_file(&acm->control->dev,
+				&dev_attr_iCountryCodeRelDate);
 	}
-	device_remove_file(&intf->dev, &dev_attr_bmCapabilities);
+	device_remove_file(&acm->control->dev, &dev_attr_bmCapabilities);
 	acm->dev = NULL;
 	usb_set_intfdata(acm->control, NULL);
 	usb_set_intfdata(acm->data, NULL);

Alan Stern