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>
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 8f78d7b..2a3196a 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -519,10 +519,13 @@
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)