From: Yi Yang Date: Tue, 28 Jun 2022 08:35:15 +0000 (+0800) Subject: serial: 8250: fix return error code in serial8250_request_std_resource() X-Git-Tag: v4.9.324~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f7a4aabcb3aced96d7ae4c82222b9739bb979a74;p=thirdparty%2Fkernel%2Fstable.git 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 Cc: stable Link: https://lore.kernel.org/r/20220628083515.64138-1-yiyang13@huawei.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index d3f17b23ac61f..d337a6d022825 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -2789,8 +2789,10 @@ 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;