Commit d5643d22 authored by Bastien Nocera's avatar Bastien Nocera Committed by Greg Kroah-Hartman
Browse files

USB: Fix device driver race 



When a new device with a specialised device driver is plugged in, the
new driver will be modprobe()'d but the driver core will attach the
"generic" driver to the device.

After that, nothing will trigger a reprobe when the modprobe()'d device
driver has finished initialising, as the device has the "generic"
driver attached to it.

Trigger a reprobe ourselves when new specialised drivers get registered.

Fixes: 88b7381a ("USB: Select better matching USB drivers when available")
Signed-off-by: default avatarBastien Nocera <hadess@hadess.net>
Cc: stable <stable@vger.kernel.org>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200818110445.509668-3-hadess@hadess.net


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent adb6e6ac

drivers/usb/core/driver.c

+38 −2
Original line number Diff line number Diff line
@@ -905,6 +905,35 @@ static int usb_uevent(struct device *dev, struct kobj_uevent_env *env) 
	return 0;

}



static bool is_dev_usb_generic_driver(struct device *dev)

{

	struct usb_device_driver *udd = dev->driver ?

		to_usb_device_driver(dev->driver) : NULL;



	return udd == &usb_generic_driver;

}



static int __usb_bus_reprobe_drivers(struct device *dev, void *data)

{

	struct usb_device_driver *new_udriver = data;

	struct usb_device *udev;

	int ret;



	if (!is_dev_usb_generic_driver(dev))

		return 0;



	udev = to_usb_device(dev);

	if (usb_device_match_id(udev, new_udriver->id_table) == NULL &&

	    (!new_udriver->match || new_udriver->match(udev) != 0))

		return 0;



	ret = device_reprobe(dev);

	if (ret && ret != -EPROBE_DEFER)

		dev_err(dev, "Failed to reprobe device (error %d)\n", ret);



	return 0;

}



/**

 * usb_register_device_driver - register a USB device (not interface) driver

 * @new_udriver: USB operations for the device driver
@@ -934,13 +963,20 @@ int usb_register_device_driver(struct usb_device_driver *new_udriver, 


	retval = driver_register(&new_udriver->drvwrap.driver);



	if (!retval)

	if (!retval) {

		pr_info("%s: registered new device driver %s\n",

			usbcore_name, new_udriver->name);

	else

		/*

		 * Check whether any device could be better served with

		 * this new driver

		 */

		bus_for_each_dev(&usb_bus_type, NULL, new_udriver,

				 __usb_bus_reprobe_drivers);

	} else {

		printk(KERN_ERR "%s: error %d registering device "

			"	driver %s\n",

			usbcore_name, retval, new_udriver->name);

	}



	return retval;

}

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