From patchwork Thu Feb 27 13:36:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 230359 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, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 E9B0CC3F36D for ; Thu, 27 Feb 2020 14:21:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C030424650 for ; Thu, 27 Feb 2020 14:21:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582813279; bh=kUKSzHdRRHXlQaZVmuHIoD/S65nhOWHRv5mf2gtz24U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ji0HIZUBBPMVN7UwE23x5DpGLnI+PG9Wk33uHQmGEPL5nRKJ75qmEMbwNNYoA+MFE FESf/p24MP272msfg0DtZ5iEU9nQ9PfddCw1HoXVjs4Nr7MbWERv9rE8qdRkAwZ63e GnD1Ml9YjCSpVOcbxAllUq9UNtMk4kmmLic8358c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389612AbgB0ORF (ORCPT ); Thu, 27 Feb 2020 09:17:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:57422 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389642AbgB0ORE (ORCPT ); Thu, 27 Feb 2020 09:17:04 -0500 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 B388120801; Thu, 27 Feb 2020 14:17:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582813024; bh=kUKSzHdRRHXlQaZVmuHIoD/S65nhOWHRv5mf2gtz24U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CQ83uEtRZwqxnuvpvmMRpE7eK0zXjeye5FhFaiajnTY++w3bU226Axdzc+X0PMg8H E6UyBcov/DGRqiD4xpQPa/BvsvjWeHUMybUrpC/Ane11ImDa4UzYZWbidFnn5klU3L EuNzEGofwniRU1JvxRwXBL4x/05aTrRR2ECRpX7I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Loic Poulain , Johan Hovold Subject: [PATCH 5.5 068/150] serdev: ttyport: restore client ops on deregistration Date: Thu, 27 Feb 2020 14:36:45 +0100 Message-Id: <20200227132243.004997059@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132232.815448360@linuxfoundation.org> References: <20200227132232.815448360@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Johan Hovold commit 0c5aae59270fb1f827acce182786094c9ccf598e upstream. The serdev tty-port controller driver should reset the tty-port client operations also on deregistration to avoid a NULL-pointer dereference in case the port is later re-registered as a normal tty device. Note that this can only happen with tty drivers such as 8250 which have statically allocated port structures that can end up being reused and where a later registration would not register a serdev controller (e.g. due to registration errors or if the devicetree has been changed in between). Specifically, this can be an issue for any statically defined ports that would be registered by 8250 core when an 8250 driver is being unbound. Fixes: bed35c6dfa6a ("serdev: add a tty port controller driver") Cc: stable # 4.11 Reported-by: Loic Poulain Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20200210145730.22762-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serdev/serdev-ttyport.c | 6 ++---- drivers/tty/tty_port.c | 5 +++-- include/linux/tty.h | 2 ++ 3 files changed, 7 insertions(+), 6 deletions(-) --- a/drivers/tty/serdev/serdev-ttyport.c +++ b/drivers/tty/serdev/serdev-ttyport.c @@ -265,7 +265,6 @@ struct device *serdev_tty_port_register( struct device *parent, struct tty_driver *drv, int idx) { - const struct tty_port_client_operations *old_ops; struct serdev_controller *ctrl; struct serport *serport; int ret; @@ -284,7 +283,6 @@ struct device *serdev_tty_port_register( ctrl->ops = &ctrl_ops; - old_ops = port->client_ops; port->client_ops = &client_ops; port->client_data = ctrl; @@ -297,7 +295,7 @@ struct device *serdev_tty_port_register( err_reset_data: port->client_data = NULL; - port->client_ops = old_ops; + port->client_ops = &tty_port_default_client_ops; serdev_controller_put(ctrl); return ERR_PTR(ret); @@ -312,8 +310,8 @@ int serdev_tty_port_unregister(struct tt return -ENODEV; serdev_controller_remove(ctrl); - port->client_ops = NULL; port->client_data = NULL; + port->client_ops = &tty_port_default_client_ops; serdev_controller_put(ctrl); return 0; --- a/drivers/tty/tty_port.c +++ b/drivers/tty/tty_port.c @@ -52,10 +52,11 @@ static void tty_port_default_wakeup(stru } } -static const struct tty_port_client_operations default_client_ops = { +const struct tty_port_client_operations tty_port_default_client_ops = { .receive_buf = tty_port_default_receive_buf, .write_wakeup = tty_port_default_wakeup, }; +EXPORT_SYMBOL_GPL(tty_port_default_client_ops); void tty_port_init(struct tty_port *port) { @@ -68,7 +69,7 @@ void tty_port_init(struct tty_port *port spin_lock_init(&port->lock); port->close_delay = (50 * HZ) / 100; port->closing_wait = (3000 * HZ) / 100; - port->client_ops = &default_client_ops; + port->client_ops = &tty_port_default_client_ops; kref_init(&port->kref); } EXPORT_SYMBOL(tty_port_init); --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -225,6 +225,8 @@ struct tty_port_client_operations { void (*write_wakeup)(struct tty_port *port); }; +extern const struct tty_port_client_operations tty_port_default_client_ops; + struct tty_port { struct tty_bufhead buf; /* Locked internally */ struct tty_struct *tty; /* Back pointer */