Commit 4b10f0f3 authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
Browse files

USB: race fixes for usb-serial, step 2 



- take BKL before looking up a driver to associate with a device to make
  sure the module is not unloaded after looking up but before association
  & bumping module count

Signed-off-by: default avatarOliver Neukum <oneukum@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 34ef50e5

drivers/usb/serial/usb-serial.c

+12 −2
Original line number Diff line number Diff line
@@ -685,14 +685,17 @@ int usb_serial_probe(struct usb_interface *interface, 
	int num_ports = 0;

	int max_endpoints;



	lock_kernel(); /* guard against unloading a serial driver module */

	type = search_serial_device(interface);

	if (!type) {

		unlock_kernel();

		dbg("none matched");

		return -ENODEV;

	}



	serial = create_serial (dev, interface, type);

	if (!serial) {

		unlock_kernel();

		dev_err(&interface->dev, "%s - out of memory\n", __FUNCTION__);

		return -ENOMEM;

	}
@@ -702,6 +705,7 @@ int usb_serial_probe(struct usb_interface *interface, 
		const struct usb_device_id *id;



		if (!try_module_get(type->driver.owner)) {

			unlock_kernel();

			dev_err(&interface->dev, "module get failed, exiting\n");

			kfree (serial);

			return -EIO;
@@ -712,6 +716,7 @@ int usb_serial_probe(struct usb_interface *interface, 
		module_put(type->driver.owner);



		if (retval) {

			unlock_kernel();

			dbg ("sub driver rejected device");

			kfree (serial);

			return retval;
@@ -781,6 +786,7 @@ int usb_serial_probe(struct usb_interface *interface, 
		 * properly during a later invocation of usb_serial_probe

		 */

		if (num_bulk_in == 0 || num_bulk_out == 0) {

			unlock_kernel();

			dev_info(&interface->dev, "PL-2303 hack: descriptors matched but endpoints did not\n");

			kfree (serial);

			return -ENODEV;
@@ -796,6 +802,7 @@ int usb_serial_probe(struct usb_interface *interface, 
	if (type == &usb_serial_generic_device) {

		num_ports = num_bulk_out;

		if (num_ports == 0) {

			unlock_kernel();

			dev_err(&interface->dev, "Generic device with no bulk out, not allowed.\n");

			kfree (serial);

			return -EIO;
@@ -806,6 +813,7 @@ int usb_serial_probe(struct usb_interface *interface, 
		/* if this device type has a calc_num_ports function, call it */

		if (type->calc_num_ports) {

			if (!try_module_get(type->driver.owner)) {

				unlock_kernel();

				dev_err(&interface->dev, "module get failed, exiting\n");

				kfree (serial);

				return -EIO;
@@ -831,6 +839,8 @@ int usb_serial_probe(struct usb_interface *interface, 
	max_endpoints = max(max_endpoints, num_interrupt_out);

	max_endpoints = max(max_endpoints, (int)serial->num_ports);

	serial->num_port_pointers = max_endpoints;

	unlock_kernel();



	dbg("%s - setting up %d port structures for this device", __FUNCTION__, max_endpoints);

	for (i = 0; i < max_endpoints; ++i) {

		port = kzalloc(sizeof(struct usb_serial_port), GFP_KERNEL);
@@ -1187,7 +1197,7 @@ static void fixup_generic(struct usb_serial_driver *device) 
	set_to_generic_if_null(device, shutdown);

}



int usb_serial_register(struct usb_serial_driver *driver)

int usb_serial_register(struct usb_serial_driver *driver) /* must be called with BKL held */

{

	int retval;
@@ -1211,7 +1221,7 @@ int usb_serial_register(struct usb_serial_driver *driver) 
}





void usb_serial_deregister(struct usb_serial_driver *device)

void usb_serial_deregister(struct usb_serial_driver *device) /* must be called with BKL held */

{

	info("USB Serial deregistering driver %s", device->description);

	list_del(&device->driver_list);

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