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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 D3019C83007 for ; Tue, 28 Apr 2020 22:18:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB6262072A for ; Tue, 28 Apr 2020 22:18:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726422AbgD1WST (ORCPT ); Tue, 28 Apr 2020 18:18:19 -0400 Received: from foss.arm.com ([217.140.110.172]:59982 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725934AbgD1WSS (ORCPT ); Tue, 28 Apr 2020 18:18:18 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0F1811FB; Tue, 28 Apr 2020 15:18:18 -0700 (PDT) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0E8A73F305; Tue, 28 Apr 2020 15:18:16 -0700 (PDT) References: <20200428184050.6501-1-john.stultz@linaro.org> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: John Stultz Cc: lkml , Andy Shevchenko , Russell King , Greg Kroah-Hartman , Jiri Slaby , linux-serial@vger.kernel.org Subject: Re: [PATCH v2] serial: amba-pl011: Make sure we initialize the port.lock spinlock In-reply-to: <20200428184050.6501-1-john.stultz@linaro.org> Date: Tue, 28 Apr 2020 23:18:14 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/04/20 19:40, John Stultz wrote: > Valentine reported seeing: > > [ 3.626638] INFO: trying to register non-static key. > [ 3.626639] the code is fine but needs lockdep annotation. > [ 3.626640] turning off the locking correctness validator. > [ 3.626644] CPU: 7 PID: 51 Comm: kworker/7:1 Not tainted 5.7.0-rc2-00115-g8c2e9790f196 #116 > [ 3.626646] Hardware name: HiKey960 (DT) > [ 3.626656] Workqueue: events deferred_probe_work_func > [ 3.632476] sd 0:0:0:0: [sda] Optimal transfer size 8192 bytes not a multiple of physical block size (16384 bytes) > [ 3.640220] Call trace: > [ 3.640225] dump_backtrace+0x0/0x1b8 > [ 3.640227] show_stack+0x20/0x30 > [ 3.640230] dump_stack+0xec/0x158 > [ 3.640234] register_lock_class+0x598/0x5c0 > [ 3.640235] __lock_acquire+0x80/0x16c0 > [ 3.640236] lock_acquire+0xf4/0x4a0 > [ 3.640241] _raw_spin_lock_irqsave+0x70/0xa8 > [ 3.640245] uart_add_one_port+0x388/0x4b8 > [ 3.640248] pl011_register_port+0x70/0xf0 > [ 3.640250] pl011_probe+0x184/0x1b8 > [ 3.640254] amba_probe+0xdc/0x180 > [ 3.640256] really_probe+0xe0/0x338 > [ 3.640257] driver_probe_device+0x60/0xf8 > [ 3.640259] __device_attach_driver+0x8c/0xd0 > [ 3.640260] bus_for_each_drv+0x84/0xd8 > [ 3.640261] __device_attach+0xe4/0x140 > [ 3.640263] device_initial_probe+0x1c/0x28 > [ 3.640265] bus_probe_device+0xa4/0xb0 > [ 3.640266] deferred_probe_work_func+0x7c/0xb8 > [ 3.640269] process_one_work+0x2c0/0x768 > [ 3.640271] worker_thread+0x4c/0x498 > [ 3.640272] kthread+0x14c/0x158 > [ 3.640275] ret_from_fork+0x10/0x1c > > Which seems to be due to the fact that after allocating the uap > structure, nothing initializes the spinlock. > > Its a little confusing, as uart_port_spin_lock_init() is one > place where the lock is supposed to be initialized, but it has > an exception for the case where the port is a console. > > This makes it seem like a deeper fix is needed to properly > register the console, but I'm not sure what that entails, and > Andy suggested that this approach is less invasive. > > Thus, this patch resolves the issue by initializing the spinlock > in the driver, and resolves the resulting warning. > Agreed with all of the above! Reviewed-and-tested-by: Valentin Schneider Thanks to both of you, John & Andy. > Cc: Valentin Schneider > Cc: Andy Shevchenko > Cc: Russell King > Cc: Greg Kroah-Hartman > Cc: Jiri Slaby > Cc: linux-serial@vger.kernel.org > Reported-by: Valentin Schneider > Reviewed-by: Andy Shevchenko > Signed-off-by: John Stultz > --- > v2: Added extra context in the commit message > --- > drivers/tty/serial/amba-pl011.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c > index 2296bb0f9578..458fc3d9d48c 100644 > --- a/drivers/tty/serial/amba-pl011.c > +++ b/drivers/tty/serial/amba-pl011.c > @@ -2575,6 +2575,7 @@ static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap, > uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL011_CONSOLE); > uap->port.flags = UPF_BOOT_AUTOCONF; > uap->port.line = index; > + spin_lock_init(&uap->port.lock); > > amba_ports[index] = uap;