Commit 73e487fd authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Greg Kroah-Hartman
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[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: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent ca85485c

drivers/usb/serial/console.c

+15 −2
Original line number Diff line number Diff line
@@ -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)

{

	if (usbcons_info.port) {

		unregister_console(&usbcons);

		if (usbcons_info.port->open_count)

			usbcons_info.port->open_count--;

		usbcons_info.port = NULL;

	}

}

drivers/usb/serial/usb-serial.c

+11 −5
Original line number Diff line number Diff line
@@ -168,6 +168,11 @@ static void destroy_serial(struct kref *kref) 
	kfree (serial);

}



void usb_serial_put(struct usb_serial *serial)

{

	kref_put(&serial->kref, destroy_serial);

}



/*****************************************************************************

 * Driver tty interface functions

 *****************************************************************************/
@@ -232,7 +237,7 @@ bailout_mutex_unlock: 
	port->open_count = 0;

	mutex_unlock(&port->mutex);

bailout_kref_put:

	kref_put(&serial->kref, destroy_serial);

	usb_serial_put(serial);

	return retval;

}
@@ -268,7 +273,7 @@ static void serial_close(struct tty_struct *tty, struct file * filp) 
	}



	mutex_unlock(&port->mutex);

	kref_put(&port->serial->kref, destroy_serial);

	usb_serial_put(port->serial);

}



static int serial_write (struct tty_struct * tty, const unsigned char *buf, int count)
@@ -276,7 +281,7 @@ static int serial_write (struct tty_struct * tty, const unsigned char *buf, int 
	struct usb_serial_port *port = tty->driver_data;

	int retval = -EINVAL;



	if (!port)

	if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)

		goto exit;



	dbg("%s - port %d, %d byte(s)", __FUNCTION__, port->number, count);
@@ -473,7 +478,7 @@ static int serial_read_proc (char *page, char **start, off_t off, int count, int 
			begin += length;

			length = 0;

		}

		kref_put(&serial->kref, destroy_serial);

		usb_serial_put(serial);

	}

	*eof = 1;

done:
@@ -985,6 +990,7 @@ void usb_serial_disconnect(struct usb_interface *interface) 
	struct device *dev = &interface->dev;

	struct usb_serial_port *port;



	usb_serial_console_disconnect(serial);

	dbg ("%s", __FUNCTION__);



	usb_set_intfdata (interface, NULL);
@@ -996,7 +1002,7 @@ void usb_serial_disconnect(struct usb_interface *interface) 
		}

		/* let the last holder of this object 

		 * cause it to be cleaned up */

		kref_put(&serial->kref, destroy_serial);

		usb_serial_put(serial);

	}

	dev_info(dev, "device disconnected\n");

}

drivers/usb/serial/usb-serial.h

+3 −0
Original line number Diff line number Diff line
@@ -248,13 +248,16 @@ extern int ezusb_set_reset (struct usb_serial *serial, unsigned char reset_bit); 
#ifdef CONFIG_USB_SERIAL_CONSOLE

extern void usb_serial_console_init (int debug, int minor);

extern void usb_serial_console_exit (void);

extern void usb_serial_console_disconnect(struct usb_serial *serial);

#else

static inline void usb_serial_console_init (int debug, int minor) { }

static inline void usb_serial_console_exit (void) { }

static inline void usb_serial_console_disconnect(struct usb_serial *serial) {}

#endif



/* Functions needed by other parts of the usbserial core */

extern struct usb_serial *usb_serial_get_by_index (unsigned int minor);

extern void usb_serial_put(struct usb_serial *serial);

extern int usb_serial_generic_open (struct usb_serial_port *port, struct file *filp);

extern int usb_serial_generic_write (struct usb_serial_port *port, const unsigned char *buf, int count);

extern void usb_serial_generic_close (struct usb_serial_port *port, struct file *filp);