Commit 774412bd authored Jun 28, 2022 by Yi Yang Committed by Greg Kroah-Hartman Jul 21, 2022

serial: 8250: fix return error code in serial8250_request_std_resource()



commit 6e690d54cfa802f939cefbd2fa2c91bd0b8bd1b6 upstream.

If port->mapbase = NULL in serial8250_request_std_resource() , it need
return a error code instead of 0. If uart_set_info() fail to request new
regions by serial8250_request_std_resource() but the return value of
serial8250_request_std_resource() is 0, The system incorrectly considers
that the resource application is successful and does not attempt to
restore the old setting. A null pointer reference is triggered when the
port resource is later invoked.

Signed-off-by: Yi Yang <yiyang13@huawei.com>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20220628083515.64138-1-yiyang13@huawei.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 379deb42

drivers/tty/serial/8250/8250_port.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -2917,8 +2917,10 @@ static int serial8250_request_std_resource(struct uart_8250_port *up)
		case UPIO_MEM32BE:
		case UPIO_MEM16:
		case UPIO_MEM:
		if (!port->mapbase)
		if (!port->mapbase) {
		ret = -EINVAL;
		break;
		}

		if (!request_mem_region(port->mapbase, size, "serial")) {
		ret = -EBUSY;