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

Alan Stern
2007-08-24T14:00:04Z

On Thu, 23 Aug 2007, Greg KH wrote:

> -stable review patch. If anyone has any objections, please let us know.
>
> ------------------
>
> From: Alan Stern <stern@rowland.harvard.edu>
>
> 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 <stern@rowland.harvard.edu>
> Acked-by: Oliver Neukum <oneukum@suse.de>
> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
>
> ---
> 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