From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Date: Tue, 11 Mar 2014 01:06:52 +0000 Subject: Re: [PATCH 1/2] serial_core: Unregister console in uart_remove_one_port() Message-Id: <531E61AC.6040706@hurleysoftware.com> List-Id: References: <1393593694-30262-1-git-send-email-geert@linux-m68k.org> In-Reply-To: <1393593694-30262-1-git-send-email-geert@linux-m68k.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 [ +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) >