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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 0A808C433DF for ; Fri, 29 May 2020 11:34:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D1DD8207BC for ; Fri, 29 May 2020 11:34:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590752064; bh=qiIfDGRDhLmCmqfNyI9oCVYYxVukeiaDUPgdXqd2ttw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=q8hgzvXxRQu+4SLKr2RIhkstY0cKsVvhbGU6ADqrdZU4KO8vGS1xtXgFFgPzxiMGD OfsM2Nn3VoHJqK6HPQozaKVA9tKZ5XUdqUMmLKWIF7ob2ETeMbCPX9VBrwgiGjR0mQ Mc/IqS8DsuSStxayeCQr/OTvda6JUXLIfVSaSl8I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726687AbgE2LeY (ORCPT ); Fri, 29 May 2020 07:34:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:36226 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725306AbgE2LeY (ORCPT ); Fri, 29 May 2020 07:34:24 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 BD6AC2074D; Fri, 29 May 2020 11:34:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590752062; bh=qiIfDGRDhLmCmqfNyI9oCVYYxVukeiaDUPgdXqd2ttw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=H99J23gA4rUUloXkwCU9gOqfAo95n70m/qWqJloLlyJ0MNKEGihGSXfdDyjUpjIjC kGkXIYDKyZhyx8oP7VXbe3l+gh3iZnjGJ5WnXvxQ/ho4LQsN7SXqxtnnA364gJC4Fe m/xFXsGiVaJaMfRFzJUjlISByDDGOeSPPILrP7lY= Date: Fri, 29 May 2020 13:34:19 +0200 From: Greg Kroah-Hartman To: Cristian Ciocaltea Cc: Andreas =?iso-8859-1?Q?F=E4rber?= , Manivannan Sadhasivam , Jiri Slaby , Andy Shevchenko , linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-actions@lists.infradead.org Subject: Re: [PATCH 1/1] tty: serial: owl: Initialize lock before registering port Message-ID: <20200529113419.GA1631227@kroah.com> References: <89f6393934fc6d493f8b9e87c1a6e916642b6a18.1590749143.git.cristian.ciocaltea@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <89f6393934fc6d493f8b9e87c1a6e916642b6a18.1590749143.git.cristian.ciocaltea@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 29, 2020 at 02:06:47PM +0300, Cristian Ciocaltea wrote: > Running a lockdep-enabled kernel leads to the following splat when > probing the owl-uart driver: > > [ 1.271784] b0124000.serial: ttyOWL2 at MMIO 0xb0124000 (irq = 22, base_baud = 1500000) is a owl-uart > [ 1.281226] INFO: trying to register non-static key. > [ 1.286179] the code is fine but needs lockdep annotation. > [ 1.291648] turning off the locking correctness validator. > [ 1.297125] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc7+ #70 > [ 1.303462] Hardware name: Generic DT based system > [ 1.308268] [<80111d3c>] (unwind_backtrace) from [<8010c9b8>] (show_stack+0x10/0x14) > [ 1.316003] [<8010c9b8>] (show_stack) from [<805016b4>] (dump_stack+0xb4/0xe0) > [ 1.323218] [<805016b4>] (dump_stack) from [<80182dec>] (register_lock_class+0x25c/0x8f4) > [ 1.331391] [<80182dec>] (register_lock_class) from [<8017ee34>] (__lock_acquire+0xb4/0x2ee4) > [ 1.339901] [<8017ee34>] (__lock_acquire) from [<8018291c>] (lock_acquire+0x424/0x4c8) > [ 1.347813] [<8018291c>] (lock_acquire) from [<808597b0>] (_raw_spin_lock_irqsave+0x54/0x68) > [ 1.356242] [<808597b0>] (_raw_spin_lock_irqsave) from [<80582e94>] (uart_add_one_port+0x384/0x510) > [ 1.365276] [<80582e94>] (uart_add_one_port) from [<8058b4d0>] (owl_uart_probe+0x1bc/0x248) > [ 1.373621] [<8058b4d0>] (owl_uart_probe) from [<8059c0e4>] (platform_drv_probe+0x48/0x94) > [ 1.381874] [<8059c0e4>] (platform_drv_probe) from [<805997c4>] (really_probe+0x200/0x470) > [ 1.390123] [<805997c4>] (really_probe) from [<80599c80>] (driver_probe_device+0x16c/0x1bc) > [ 1.398461] [<80599c80>] (driver_probe_device) from [<80599f18>] (device_driver_attach+0x44/0x60) > [ 1.407317] [<80599f18>] (device_driver_attach) from [<8059a078>] (__driver_attach+0x144/0x14c) > [ 1.416000] [<8059a078>] (__driver_attach) from [<805978ac>] (bus_for_each_dev+0x5c/0xb4) > [ 1.424162] [<805978ac>] (bus_for_each_dev) from [<8059896c>] (bus_add_driver+0x118/0x204) > [ 1.432410] [<8059896c>] (bus_add_driver) from [<8059ae6c>] (driver_register+0xbc/0xf8) > [ 1.440405] [<8059ae6c>] (driver_register) from [<80c1fd24>] (owl_uart_init+0x20/0x40) > [ 1.448313] [<80c1fd24>] (owl_uart_init) from [<801021d8>] (do_one_initcall+0x184/0x3a4) > [ 1.456399] [<801021d8>] (do_one_initcall) from [<80c01100>] (kernel_init_freeable+0x264/0x2e4) > [ 1.465085] [<80c01100>] (kernel_init_freeable) from [<80850a88>] (kernel_init+0x8/0x110) > [ 1.473249] [<80850a88>] (kernel_init) from [<80100114>] (ret_from_fork+0x14/0x20) > [ 1.480800] Exception stack(0xee8bdfb0 to 0xee8bdff8) > [ 1.485841] dfa0: 00000000 00000000 00000000 00000000 > [ 1.494002] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > [ 1.502162] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 > [ 1.508914] printk: console [ttyOWL2] enabled > > The locking issue occurs in uart_configure_port() when trying to > guard the call to set_mctrl(). > > uart_add_one_port() should normally initialize the spinlock via > uart_port_spin_lock_init(), but it never happens because the port is > detected as a console and, as a consequence, the spinlock is expected > to be already initialized. > > The commit a3cb39d258ef > ("serial: core: Allow detach and attach serial device for console") > changed the lock initialization logic to assume the spinlock is > initialized even if the console is not enabled. > > Therefore, initialize the lock explicitly in owl_uart_probe(), before > attempting to invoke uart_add_one_port(). > > Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") > Signed-off-by: Cristian Ciocaltea > --- > drivers/tty/serial/owl-uart.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c > index c149f8c30007..c2fa2f15d50a 100644 > --- a/drivers/tty/serial/owl-uart.c > +++ b/drivers/tty/serial/owl-uart.c > @@ -705,6 +705,8 @@ static int owl_uart_probe(struct platform_device *pdev) > owl_uart_ports[pdev->id] = owl_port; > platform_set_drvdata(pdev, owl_port); > > + spin_lock_init(&owl_port->port.lock); > + > ret = uart_add_one_port(&owl_uart_driver, &owl_port->port); > if (ret) > owl_uart_ports[pdev->id] = NULL; Ugh, another one :( Thanks for this, will queue this up now. greg k-h