From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754687AbaCKBHC (ORCPT ); Mon, 10 Mar 2014 21:07:02 -0400 Received: from mailout32.mail01.mtsvc.net ([216.70.64.70]:37233 "EHLO n23.mail01.mtsvc.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754665AbaCKBG6 (ORCPT ); Mon, 10 Mar 2014 21:06:58 -0400 Message-ID: <531E61AC.6040706@hurleysoftware.com> Date: Mon, 10 Mar 2014 21:06:52 -0400 From: Peter Hurley User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Geert Uytterhoeven , Greg Kroah-Hartman , Jiri Slaby CC: Laurent Pinchart , linux-serial@vger.kernel.org, linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven , One Thousand Gnomes Subject: Re: [PATCH 1/2] serial_core: Unregister console in uart_remove_one_port() References: <1393593694-30262-1-git-send-email-geert@linux-m68k.org> In-Reply-To: <1393593694-30262-1-git-send-email-geert@linux-m68k.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated-User: 990527 peter@hurleysoftware.com X-MT-ID: 8FA290C2A27252AACF65DBC4A42F3CE3735FB2A4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ +cc Alan ] On 02/28/2014 08:21 AM, Geert Uytterhoeven wrote: > From: Geert Uytterhoeven > > If the serial port being removed is used as a console, it must also be > unregistered from the console subsystem using unregister_console(). > > uart_ops.release_port() will release resources (e.g. iounmap() the serial > port registers), causing a crash on subsequent kernel output if the console > is still registered. This brings up an interesting point: where are the serial_core drivers indicating to the tty core that the port is bound to a console? IOW, I cannot find a single 'port->console = 1' anywhere in the serial tree. It would be bad if the uart port disappears while a console is running on it... > Signed-off-by: Geert Uytterhoeven > --- > drivers/tty/serial/serial_core.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c > index ece2049bd270..8ece7f14d89d 100644 > --- a/drivers/tty/serial/serial_core.c > +++ b/drivers/tty/serial/serial_core.c > @@ -2677,6 +2677,12 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport) > tty_vhangup(port->tty); > > /* > + * If the port is used as a console, unregister it > + */ > + if (uart_console(uport)) > + unregister_console(uport->cons); > + > + /* > * Free the port IO and memory resources, if any. > */ > if (uport->type != PORT_UNKNOWN) >