Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a7cfaf16 authored by Fabio Estevam's avatar Fabio Estevam Committed by Greg Kroah-Hartman
Browse files

serial: serial_core: Perform NULL checks for release/request_port ops 



Doing the following UART bind/unbind sequence on a i.mx platform causes
a kernel crash due to NULL pointer dereference:

echo  21f4000.serial > /sys/bus/platform/drivers/imx-uart/bind
echo  21f4000.serial > /sys/bus/platform/drivers/imx-uart/unbind

Fix this problem by adding NULL checks prior to calling release/request_port
ops.

Reported-by: default avatarFugang Duan <fugang.duan@nxp.com>
Signed-off-by: default avatarFabio Estevam <fabio.estevam@nxp.com>
Tested-by: default avatarFugang Duan <fugang.duan@nxp.com>
Acked-by: default avatarFugang Duan <fugang.duan@nxp.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3e5af8e0

drivers/tty/serial/serial_core.c

+4 −4
Original line number Diff line number Diff line
@@ -887,7 +887,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, 
		/*

		 * Free and release old regions

		 */

		if (old_type != PORT_UNKNOWN)

		if (old_type != PORT_UNKNOWN && uport->ops->release_port)

			uport->ops->release_port(uport);



		uport->iobase = new_port;
@@ -900,7 +900,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, 
		/*

		 * Claim and map the new regions

		 */

		if (uport->type != PORT_UNKNOWN) {

		if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {

			retval = uport->ops->request_port(uport);

		} else {

			/* Always success - Jean II */
@@ -1125,7 +1125,7 @@ static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state) 
		 * If we already have a port type configured,

		 * we must release its resources.

		 */

		if (uport->type != PORT_UNKNOWN)

		if (uport->type != PORT_UNKNOWN && uport->ops->release_port)

			uport->ops->release_port(uport);



		flags = UART_CONFIG_TYPE;
@@ -2897,7 +2897,7 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport) 
	/*

	 * Free the port IO and memory resources, if any.

	 */

	if (uport->type != PORT_UNKNOWN)

	if (uport->type != PORT_UNKNOWN && uport->ops->release_port)

		uport->ops->release_port(uport);

	kfree(uport->tty_groups);