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Commit 49c02304 authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
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serial: core: Expand port mutex section in uart_poll_init() 



Prepare uart_poll_init() to safely dereference uart port; expand the
port mutex section to guarantee uart port remains valid until
uart_poll_init() completes.

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5c0517fe

drivers/tty/serial/serial_core.c

+15 −15
Original line number Diff line number Diff line
@@ -2230,42 +2230,42 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options) 
{

	struct uart_driver *drv = driver->driver_state;

	struct uart_state *state = drv->state + line;

	struct tty_port *tport;

	struct uart_port *port;

	int baud = 9600;

	int bits = 8;

	int parity = 'n';

	int flow = 'n';

	int ret;

	int ret = 0;



	if (!state || !state->uart_port)

	if (!state)

		return -1;



	tport = &state->port;

	mutex_lock(&tport->mutex);



	port = state->uart_port;

	if (!(port->ops->poll_get_char && port->ops->poll_put_char))

		return -1;

	if (!(port->ops->poll_get_char && port->ops->poll_put_char)) {

		ret = -1;

		goto out;

	}



	if (port->ops->poll_init) {

		struct tty_port *tport = &state->port;



		ret = 0;

		mutex_lock(&tport->mutex);

		/*

		 * We don't set initialized as we only initialized the hw,

		 * e.g. state->xmit is still uninitialized.

		 */

		if (!tty_port_initialized(tport))

			ret = port->ops->poll_init(port);

		mutex_unlock(&tport->mutex);

		if (ret)

			return ret;

	}



	if (options) {

	if (!ret && options) {

		uart_parse_options(options, &baud, &parity, &bits, &flow);

		return uart_set_options(port, NULL, baud, parity, bits, flow);

		ret = uart_set_options(port, NULL, baud, parity, bits, flow);

	}



	return 0;

out:

	mutex_unlock(&tport->mutex);

	return ret;

}



static int uart_poll_get_char(struct tty_driver *driver, int line)