From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: [PATCH] serial: 8250: Prevent kernel crash with nr_uarts=0 Date: Mon, 04 May 2015 18:01:24 +0200 Message-ID: <554797D4.5080704@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: Greg Kroah-Hartman Cc: Linux Kernel Mailing List , linux-serial@vger.kernel.org List-Id: linux-serial@vger.kernel.org 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 that function if there are no uarts. Signed-off-by: Jan Kiszka --- drivers/tty/serial/8250/8250_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 4506e40..e1363a40 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -3256,7 +3256,7 @@ static void __init serial8250_isa_init_ports(void) static int first = 1; int i, irqflag = 0; - if (!first) + if (!first || nr_uarts == 0) return; first = 0; -- 2.1.4