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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C88D5C001DE for ; Sun, 6 Aug 2023 04:34:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229777AbjHFEeF (ORCPT ); Sun, 6 Aug 2023 00:34:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229458AbjHFEeC (ORCPT ); Sun, 6 Aug 2023 00:34:02 -0400 Received: from muru.com (muru.com [72.249.23.125]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 4914A1FDE; Sat, 5 Aug 2023 21:34:00 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 4157480A0; Sun, 6 Aug 2023 04:33:59 +0000 (UTC) Date: Sun, 6 Aug 2023 07:33:57 +0300 From: Tony Lindgren To: Guenter Roeck Cc: Greg Kroah-Hartman , Jiri Slaby , Andy Shevchenko , Andy Shevchenko , Dhruva Gole , Ilpo =?utf-8?B?SsOkcnZpbmVu?= , John Ogness , Johan Hovold , Sebastian Andrzej Siewior , Vignesh Raghavendra , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, kernel test robot Subject: Re: [PATCH v2 1/1] serial: core: Fix serial_base_match() after fixing controller port name Message-ID: <20230806043357.GL14799@atomide.com> References: <20230803071034.25571-1-tony@atomide.com> <0e1bc27d-dc84-473d-bfdf-db0743c5d64a@roeck-us.net> <20230805044910.GJ14799@atomide.com> <20230805114846.GK14799@atomide.com> <095e0120-ba81-64e7-e5d0-c042fb64978f@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <095e0120-ba81-64e7-e5d0-c042fb64978f@roeck-us.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Guenter Roeck [230805 16:12]: > On 8/5/23 08:50, Guenter Roeck wrote: > > On 8/5/23 04:48, Tony Lindgren wrote: > > > * Guenter Roeck [230805 10:50]: > > > > On 8/4/23 21:49, Tony Lindgren wrote: > > > > > * Guenter Roeck [230804 21:42]: > > > > > > kobject: kobject_add_internal failed for serial8250.0:0.0 with -EEXIST, don't try to register things with the same name in the same directory. > > > > > > serial8250 serial8250.0: unable to register port at index 1 (IO2f8 MEM0 IRQ3): -17 > > > > > > sysfs: cannot create duplicate filename '/devices/platform/serial8250.0/serial8250.0:0/serial8250.0:0.0' > > > > > > > > > > The issue above should be fixed with commit: > > > > > > > > > > bbb4abb1bcfb ("serial: 8250: Reinit port_id when adding back serial8250_isa_devs") > > > > > > > > > > > > > No. I tested the tip of tty-linus (v6.5-rc4-9-gdfe2aeb226fd) which includes > > > > above commit, but still see the problem. sparc images also still stall after > > > > the "cannot create duplicate filename" message. > > > > I bisected the sparc problem - it also bisects to commit d962de6ae51f. > > > > > > > > The problem affects all mips boot tests, all sparc boot tests, as well as > > > > arm sx1, ppc bamboo and sam460ex emulations. As far as I can see, those > > > > call serial8250_register_8250_port() without calling  serial8250_setup_port() > > > > and thus don't set port_id. I am only testing a few of those, so I strongly > > > > suspect that all similar callers of serial8250_register_8250_port() are > > > > affected (i.e., almost all of them) if they register more than one serial port. > > > > > > OK thanks for explaining. So we need to initialize port->port_id for the > > > multi-port instances to avoid being stuck with the port->line index. I'll > > > take a look. > > > > > > I wonder if we should just revert d962de6ae51f for now. It needs to be > > > tested to see if something else also needs reverting though. > > > > > > > It is actually more complicated like that. Adding some debug into, I get the following > > from a mips boot. Turns out that serial8250_setup_port() is actually called. > > > > ... > > ####### serial8250_setup_port: index 0 > > ####### serial8250_setup_port: index 0 returning 819a5ab8 > > ####### serial8250_setup_port: index 1 > > ####### serial8250_setup_port: index 1 returning 819a5d20 > > ####### serial8250_setup_port: index 2 > > ####### serial8250_setup_port: index 2 returning 819a5f88 > > ####### serial8250_setup_port: index 3 > > ####### serial8250_setup_port: index 3 returning 819a61f0 > > ... > > #### serial8250_register_8250_port: uart=819a5ab8 > > #### serial8250_register_8250_port: uart=819a5ab8 port_id=0 line=0 > > ... > > #### serial8250_register_8250_port: uart=819a5d20 > > #### serial8250_register_8250_port: uart=819a5d20 port_id=1 line=1 > > sysfs: cannot create duplicate filename '/devices/platform/serial8250.0/serial8250.0:0/serial8250.0:0.0' > > > > So line and port_id are both set, but the created sysfs attribute > > is still duplicate. I'll do some more debugging. > > > > Ok, it is actually quite simple. In serial8250_register_8250_port(), > uart->port.port_id has the correct and expected value. However, that is > overwritten with > uart->port.port_id = up->port.port_id; > where 'up' is the port pointer passed by the caller of serial8250_register_8250_port(). > And 'port_id' is always 0 in _that_ port pointer (while 'line' is set correctly). To me it seems we can't use port->port_id until multiport drivers initialize it, or set port->port_id automatically with ida_alloc(). Meanwhile, we can just change back to using port->line assuming that fixes the issue for your tests. This means the port names are broken like we had in -rc1 but that's a cosmetic issue for now. Below is what I have in mind for a partial revert of commit d962de6ae51f. Regards, Tony 8< ------------------ diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c --- a/drivers/tty/serial/serial_base_bus.c +++ b/drivers/tty/serial/serial_base_bus.c @@ -151,7 +151,7 @@ struct serial_port_device *serial_base_port_add(struct uart_port *port, err = serial_base_device_init(port, &port_dev->dev, &ctrl_dev->dev, &serial_port_type, serial_base_port_release, - port->ctrl_id, port->port_id); + port->ctrl_id, port->line); if (err) goto err_put_device; -- 2.41.0