--- drivers/usb/serial/usb-serial.c.alt	2006-12-17 14:57:40.000000000 +0100
+++ drivers/usb/serial/usb-serial.c	2006-12-20 18:22:41.000000000 +0100
@@ -59,6 +59,7 @@
 
 static int debug;
 static struct usb_serial *serial_table[SERIAL_TTY_MINORS];	/* initially all NULL */
+static DECLARE_MUTEX(table_lock); /* lock for serial_table */
 static LIST_HEAD(usb_serial_driver_list);
 
 struct usb_serial *usb_serial_get_by_index(unsigned index)
@@ -176,7 +177,9 @@
 	dbg("%s", __FUNCTION__);
 
 	/* get the serial object associated with this tty pointer */
+	mutex_lock(&table_lock);
 	serial = usb_serial_get_by_index(tty->index);
+	mutex_unlock(&table_lock);
 	if (!serial) {
 		tty->driver_data = NULL;
 		return -ENODEV;
@@ -265,7 +268,9 @@
 	}
 
 	mutex_unlock(&port->mutex);
+	mutex_lock(&table_lock);
 	usb_serial_put(port->serial);
+	mutex_unlock(&table_lock);
 }
 
 static int serial_write (struct tty_struct * tty, const unsigned char *buf, int count)
@@ -771,7 +776,9 @@
 			num_ports = type->num_ports;
 	}
 
+	mutex_lock(&table_lock);
 	if (get_free_serial (serial, num_ports, &minor) == NULL) {
+		mutex_unlock(&table_lock);
 		dev_err(&interface->dev, "No more free serial devices\n");
 		kfree (serial);
 		return -ENOMEM;
@@ -921,6 +928,7 @@
 		if (retval > 0) {
 			/* quietly accept this device, but don't bind to a serial port
 			 * as it's about to disappear */
+			mutex_unlock(&table_lock);
 			goto exit;
 		}
 	}
@@ -941,6 +949,7 @@
 				"continuing\n");
 	}
 
+	mutex_unlock(&table_lock);
 	usb_serial_console_init (debug, minor);
 
 exit:
@@ -980,6 +989,7 @@
 
 	/* return the minor range that this device had */
 	return_serial (serial);
+	mutex_unlock(&table_lock);
 
 	/* free up any memory that we allocated */
 	for (i = 0; i < serial->num_port_pointers; ++i)
@@ -999,6 +1009,7 @@
 	dbg ("%s", __FUNCTION__);
 
 	usb_set_intfdata (interface, NULL);
+	mutex_lock(&table_lock);
 	if (serial) {
 		for (i = 0; i < serial->num_ports; ++i) {
 			port = serial->port[i];
@@ -1009,6 +1020,7 @@
 		 * cause it to be cleaned up */
 		usb_serial_put(serial);
 	}
+	mutex_unlock(&table_lock);
 	dev_info(dev, "device disconnected\n");
 }
 
@@ -1060,6 +1072,7 @@
 	usb_serial_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 	usb_serial_tty_driver->init_termios = tty_std_termios;
 	usb_serial_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+	init_MUTEX(&table_lock);
 	tty_set_operations(usb_serial_tty_driver, &serial_ops);
 	result = tty_register_driver(usb_serial_tty_driver);
 	if (result) {