From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBFEFC433E2 for ; Wed, 16 Sep 2020 17:54:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6FCA12074B for ; Wed, 16 Sep 2020 17:54:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600278840; bh=lqzdIOQ2v5uAaJ5UDf7Rkv6xvR9w50zt6VNuSmWbeD0=; h=Subject:To:From:Date:List-ID:From; b=PdVfQO2SYIlheQEROUCJa+mYwlH9SI5WGCprbmReZdkzafAuYd5Sx7xhOSn2e3PoX tkUYvBwKkTQD9w0lKH0TOe5bC0GAbxSG2WcNyzhsBmCriVmjbzbuZ0JoGy52EAWi1e QmQpOpgZnJlvFVjzwCqYCPzMvoDs4WjQtA4qykL8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727290AbgIPRxH (ORCPT ); Wed, 16 Sep 2020 13:53:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:42918 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727222AbgIPRwC (ORCPT ); Wed, 16 Sep 2020 13:52:02 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3EB8521D43; Wed, 16 Sep 2020 11:23:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600255404; bh=lqzdIOQ2v5uAaJ5UDf7Rkv6xvR9w50zt6VNuSmWbeD0=; h=Subject:To:From:Date:From; b=tMqy+fB5WUjofla58yU2ip14yDHBdK1kGt1tjcWXaE5IC1BayfYMFsxTZwE9WJ3M5 cZYqbfB2x0RrmBq7NGWhuHxWOiW72XvtnFywIlKy/ToHA5RMhMex58zxPQpkns3oPQ 0QwMDcSXXC7jFGo9BVL+77as/mPF7PYFkww2SRHM= Subject: patch "serial: core: fix console port-lock regression" added to tty-linus To: johan@kernel.org, andriy.shevchenko@linux.intel.com, gregkh@linuxfoundation.org, stable@vger.kernel.org From: Date: Wed, 16 Sep 2020 13:23:56 +0200 Message-ID: <1600255436723@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled serial: core: fix console port-lock regression to my tty git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git in the tty-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From e0830dbf71f191851ed3772d2760f007b7c5bc3a Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 9 Sep 2020 16:31:01 +0200 Subject: serial: core: fix console port-lock regression Fix the port-lock initialisation regression introduced by commit a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") by making sure that the lock is again initialised during console setup. The console may be registered before the serial controller has been probed in which case the port lock needs to be initialised during console setup by a call to uart_set_options(). The console-detach changes introduced a regression in several drivers by effectively removing that initialisation by not initialising the lock when the port is used as a console (which is always the case during console setup). Add back the early lock initialisation and instead use a new console-reinit flag to handle the case where a console is being re-attached through sysfs. The question whether the console-detach interface should have been added in the first place is left for another discussion. Note that the console-enabled check in uart_set_options() is not redundant because of kgdboc, which can end up reinitialising an already enabled console (see commit 42b6a1baa3ec ("serial_core: Don't re-initialize a previously initialized spinlock.")). Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Cc: stable # 5.7 Signed-off-by: Johan Hovold Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200909143101.15389-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 32 +++++++++++++++----------------- include/linux/serial_core.h | 1 + 2 files changed, 16 insertions(+), 17 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 53b79e1fcbc8..124524ecfe26 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1916,24 +1916,12 @@ static inline bool uart_console_enabled(struct uart_port *port) return uart_console(port) && (port->cons->flags & CON_ENABLED); } -static void __uart_port_spin_lock_init(struct uart_port *port) +static void uart_port_spin_lock_init(struct uart_port *port) { spin_lock_init(&port->lock); lockdep_set_class(&port->lock, &port_lock_key); } -/* - * Ensure that the serial console lock is initialised early. - * If this port is a console, then the spinlock is already initialised. - */ -static inline void uart_port_spin_lock_init(struct uart_port *port) -{ - if (uart_console(port)) - return; - - __uart_port_spin_lock_init(port); -} - #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL) /** * uart_console_write - write a console message to a serial port @@ -2086,7 +2074,15 @@ uart_set_options(struct uart_port *port, struct console *co, struct ktermios termios; static struct ktermios dummy; - uart_port_spin_lock_init(port); + /* + * Ensure that the serial-console lock is initialised early. + * + * Note that the console-enabled check is needed because of kgdboc, + * which can end up calling uart_set_options() for an already enabled + * console via tty_find_polling_driver() and uart_poll_init(). + */ + if (!uart_console_enabled(port) && !port->console_reinit) + uart_port_spin_lock_init(port); memset(&termios, 0, sizeof(struct ktermios)); @@ -2794,10 +2790,12 @@ static ssize_t console_store(struct device *dev, if (oldconsole && !newconsole) { ret = unregister_console(uport->cons); } else if (!oldconsole && newconsole) { - if (uart_console(uport)) + if (uart_console(uport)) { + uport->console_reinit = 1; register_console(uport->cons); - else + } else { ret = -ENOENT; + } } } else { ret = -ENXIO; @@ -2898,7 +2896,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport) * initialised. */ if (!uart_console_enabled(uport)) - __uart_port_spin_lock_init(uport); + uart_port_spin_lock_init(uport); if (uport->cons && uport->dev) of_console_check(uport->dev->of_node, uport->cons->name, uport->line); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 01fc4d9c9c54..8a99279a579b 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -248,6 +248,7 @@ struct uart_port { unsigned char hub6; /* this should be in the 8250 driver */ unsigned char suspended; + unsigned char console_reinit; const char *name; /* port name */ struct attribute_group *attr_group; /* port specific attributes */ const struct attribute_group **tty_groups; /* all attributes (serial core use only) */ -- 2.28.0