From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Helgaas Date: Thu, 16 Oct 2003 16:58:56 +0000 Subject: [PATCH] serial console registration bugfix (2.6) Message-Id: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org uart_set_options() can dereference a null pointer. This happens if you specify a console that hasn't previously been setup by early_serial_setup(). For example, on ia64, the HCDP typically tells us about line 0, so we calls early_serial_setup() for it. If the user specifies "console=ttyS3", we machine-check when trying to follow the uninitialized port->ops pointer. It's not entirely clear to me whether we should return 0 or -ENODEV or something. The advantage of returning zero is that if the user specifies "console=ttyS0" and we just lack the HCDP, the console doesn't work as early as usual, but it does start working after the serial driver detects the port (though the baud/parity/etc from the command line are lost). Returning -ENODEV seems to prevent it from ever working. Bjorn === drivers/serial/serial_core.c 1.72 vs edited ==--- 1.72/drivers/serial/serial_core.c Mon Sep 29 18:35:33 2003 +++ edited/drivers/serial/serial_core.c Thu Oct 16 09:56:55 2003 @@ -1859,6 +1859,9 @@ if (flow = 'r') termios.c_cflag |= CRTSCTS; + if (!port->ops) + return 0; + port->ops->set_termios(port, &termios, NULL); co->cflag = termios.c_cflag;