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=-14.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 468FEC2D0A3 for ; Thu, 12 Nov 2020 08:39:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE23922202 for ; Thu, 12 Nov 2020 08:39:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="c6Izn5B2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725986AbgKLIjj (ORCPT ); Thu, 12 Nov 2020 03:39:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:58052 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725947AbgKLIji (ORCPT ); Thu, 12 Nov 2020 03:39:38 -0500 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 26ECD221FF; Thu, 12 Nov 2020 08:39:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605170377; bh=8taqSHxWFbByQnJia3D5L0Jw6PY/pFgoThAEcX64R7g=; h=Subject:To:From:Date:From; b=c6Izn5B2WeprUvRimR/SXGZu0tZdebvQ4AL7UI+7ukt+WBLRDwpItcWb/4yOj3vbn 8sPUZ/qFsmDn4Otj6jVPwY31wSDkuKzKyiUi1OhIpvrzcO+pMOAPbXxHpe+PzaZKi7 ql2BwMbs4M+6mdlA5i4aoF8EA7K1FuK4eOkOwK54= Subject: patch "tty: serial: imx: keep console clocks always on" added to tty-linus To: fugang.duan@nxp.com, gregkh@linuxfoundation.org, stable@vger.kernel.org, u.kleine-koenig@pengutronix.de From: Date: Thu, 12 Nov 2020 09:40:29 +0100 Message-ID: <160517042921119@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 tty: serial: imx: keep console clocks always on 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 e67c139c488e84e7eae6c333231e791f0e89b3fb Mon Sep 17 00:00:00 2001 From: Fugang Duan Date: Wed, 11 Nov 2020 10:51:36 +0800 Subject: tty: serial: imx: keep console clocks always on MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit For below code, there has chance to cause deadlock in SMP system: Thread 1: clk_enable_lock(); pr_info("debug message"); clk_enable_unlock(); Thread 2: imx_uart_console_write() clk_enable() clk_enable_lock(); Thread 1: Acuired clk enable_lock -> printk -> console_trylock_spinning Thread 2: console_unlock() -> imx_uart_console_write -> clk_disable -> Acquite clk enable_lock So the patch is to keep console port clocks always on like other console drivers. Fixes: 1cf93e0d5488 ("serial: imx: remove the uart_console() check") Acked-by: Uwe Kleine-König Signed-off-by: Fugang Duan Link: https://lore.kernel.org/r/20201111025136.29818-1-fugang.duan@nxp.com Cc: stable [fix up build warning - gregkh] Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 20 +++----------------- 1 file changed, 3 insertions(+), 17 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 3c53a3c89959..cacf7266a262 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -2008,16 +2008,6 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count) unsigned int ucr1; unsigned long flags = 0; int locked = 1; - int retval; - - retval = clk_enable(sport->clk_per); - if (retval) - return; - retval = clk_enable(sport->clk_ipg); - if (retval) { - clk_disable(sport->clk_per); - return; - } if (sport->port.sysrq) locked = 0; @@ -2053,9 +2043,6 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count) if (locked) spin_unlock_irqrestore(&sport->port.lock, flags); - - clk_disable(sport->clk_ipg); - clk_disable(sport->clk_per); } /* @@ -2156,15 +2143,14 @@ imx_uart_console_setup(struct console *co, char *options) retval = uart_set_options(&sport->port, co, baud, parity, bits, flow); - clk_disable(sport->clk_ipg); if (retval) { - clk_unprepare(sport->clk_ipg); + clk_disable_unprepare(sport->clk_ipg); goto error_console; } - retval = clk_prepare(sport->clk_per); + retval = clk_prepare_enable(sport->clk_per); if (retval) - clk_unprepare(sport->clk_ipg); + clk_disable_unprepare(sport->clk_ipg); error_console: return retval; -- 2.29.2