[PATCH] USB console: fix disconnection issues

Prevent sending further output to a USB-serial console after the dongle is
disconnected, take care not to leak kref.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c
index fc4a0f731d91..f3404e10afb4 100644
--- a/drivers/usb/serial/console.c
+++ b/drivers/usb/serial/console.c
@@ -202,7 +202,7 @@ static void usb_console_write(struct console *co, const char *buf, unsigned coun
         struct usb_serial *serial;
         int retval = -ENODEV;
 
-        if (!port)
+        if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
                 return;
         serial = port->serial;
 
@@ -255,6 +255,14 @@ static struct console usbcons = {
         .index =        -1,
 };
 
+void usb_serial_console_disconnect(struct usb_serial *serial)
+{
+        if (serial && serial->port && serial->port[0] && serial->port[0] == usbcons_info.port) {
+                usb_serial_console_exit();
+                usb_serial_put(serial);
+        }
+}
+
 void usb_serial_console_init (int serial_debug, int minor)
 {
         debug = serial_debug;
@@ -280,6 +288,11 @@ void usb_serial_console_init (int serial_debug, int minor)
 
 void usb_serial_console_exit (void)
 {
-        unregister_console(&usbcons);
+        if (usbcons_info.port) {
+                unregister_console(&usbcons);
+                if (usbcons_info.port->open_count)
+                        usbcons_info.port->open_count--;
+                usbcons_info.port = NULL;
+        }
 }