serial: 8250: Do nothing if nr_uarts=0

When nr_uarts was set to 0 (via config or 8250_core.nr_uarts), we crash
early on x86 because serial8250_isa_init_ports dereferences base_ops
which remains NULL. In fact, there is nothing to do for all the callers
of serial8250_isa_init_ports if there are no uarts.

Based on suggestions by Peter Hurley.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jan Kiszka 2015-05-05 08:26:27 +02:00 committed by Greg Kroah-Hartman
parent 24ee4df122
commit 59cfc45f17

View file

@ -3535,6 +3535,9 @@ static struct console univ8250_console = {
static int __init univ8250_console_init(void)
{
if (nr_uarts == 0)
return -ENODEV;
serial8250_isa_init_ports();
register_console(&univ8250_console);
return 0;
@ -3565,7 +3568,7 @@ int __init early_serial_setup(struct uart_port *port)
{
struct uart_port *p;
if (port->line >= ARRAY_SIZE(serial8250_ports))
if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
return -ENODEV;
serial8250_isa_init_ports();
@ -3932,6 +3935,9 @@ static int __init serial8250_init(void)
{
int ret;
if (nr_uarts == 0)
return -ENODEV;
serial8250_isa_init_ports();
printk(KERN_INFO "Serial: 8250/16550 driver, "