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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no 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 8D4E5C433E0 for ; Mon, 13 Jul 2020 10:09:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6CE7B20758 for ; Mon, 13 Jul 2020 10:09:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729460AbgGMKJD (ORCPT ); Mon, 13 Jul 2020 06:09:03 -0400 Received: from mx2.suse.de ([195.135.220.15]:41586 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726523AbgGMKJC (ORCPT ); Mon, 13 Jul 2020 06:09:02 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 327C0B138; Mon, 13 Jul 2020 10:09:03 +0000 (UTC) Message-ID: <1594634939.2541.3.camel@suse.de> Subject: Re: [PATCH] cdc-acm: acm_init: Set initial BAUD to B0 From: Oliver Neukum To: Joakim Tjernlund , "linux-usb @ vger . kernel . org" Cc: stable@vger.kernel.org Date: Mon, 13 Jul 2020 12:08:59 +0200 In-Reply-To: <20200710093518.22272-1-joakim.tjernlund@infinera.com> References: <20200710093518.22272-1-joakim.tjernlund@infinera.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Am Freitag, den 10.07.2020, 11:35 +0200 schrieb Joakim Tjernlund: > Hi, > --- a/drivers/usb/class/cdc-acm.c > +++ b/drivers/usb/class/cdc-acm.c > @@ -1999,19 +1999,19 @@ static int __init acm_init(void) > acm_tty_driver->subtype = SERIAL_TYPE_NORMAL, > acm_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV; > acm_tty_driver->init_termios = tty_std_termios; > - acm_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | > + acm_tty_driver->init_termios.c_cflag = B0 | CS8 | CREAD | > HUPCL | CLOCAL; > tty_set_operations(acm_tty_driver, &acm_ops); > > - retval = tty_register_driver(acm_tty_driver); > + retval = usb_register(&acm_driver); No, you cannot do that. This means that probe() is now live. Probe() in turn does this: tty_dev = tty_port_register_device(&acm->port, acm_tty_driver, minor, &control_interface->dev); if (IS_ERR(tty_dev)) { rv = PTR_ERR(tty_dev); goto alloc_fail6; } That is just not a good idea when the tty is not already registered. You are opening up a race. Regards Oliver