Commit 50dbb852 authored Mar 17, 2010 by Johan Hovold Committed by Greg Kroah-Hartman May 20, 2010

USB: serial: fix missing locking on fifo in write callback



On errors the fifo was reset without any locking. This could race with
write which do kfifo_put and perhaps also chars_in_buffer and write_room.

Every other access to the fifo is protected using the port lock so
better add it to the error path as well.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

parent 30af7fb5

drivers/usb/serial/generic.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -519,11 +519,14 @@ void usb_serial_generic_write_bulk_callback(struct urb *urb)
		port->write_urb_busy = 0;
		spin_unlock_irqrestore(&port->lock, flags);

		if (status)
		if (status) {
		spin_lock_irqsave(&port->lock, flags);
		kfifo_reset_out(&port->write_fifo);
		else
		spin_unlock_irqrestore(&port->lock, flags);
		} else {
		usb_serial_generic_write_start(port);
		}
		}

		if (status)
		dbg("%s - non-zero urb status: %d", __func__, status);