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 7A290EB64DA for ; Thu, 20 Jul 2023 06:57:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231394AbjGTG5Z (ORCPT ); Thu, 20 Jul 2023 02:57:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229651AbjGTG5W (ORCPT ); Thu, 20 Jul 2023 02:57:22 -0400 Received: from out30-101.freemail.mail.aliyun.com (out30-101.freemail.mail.aliyun.com [115.124.30.101]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FFEACC; Wed, 19 Jul 2023 23:57:18 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R131e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045176;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VnovSVt_1689836233; Received: from 30.97.48.52(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VnovSVt_1689836233) by smtp.aliyun-inc.com; Thu, 20 Jul 2023 14:57:14 +0800 Message-ID: <7c7e062f-40d2-a3d9-6a25-0ef3defe2caf@linux.alibaba.com> Date: Thu, 20 Jul 2023 14:57:34 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH V2 1/2] serial: sprd: Assign sprd_port after initialized to avoid wrong access To: Chunyan Zhang , Greg Kroah-Hartman , Jiri Slaby Cc: linux-serial@vger.kernel.org, Orson Zhai , Chunyan Zhang , LKML References: <20230713031904.12106-1-chunyan.zhang@unisoc.com> From: Baolin Wang In-Reply-To: <20230713031904.12106-1-chunyan.zhang@unisoc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/13/2023 11:19 AM, Chunyan Zhang wrote: > The global pointer 'sprd_port' may not zero when sprd_probe returns > failure, that is a risk for sprd_port to be accessed afterward, and > may lead to unexpected errors. > > For example: > > There are two UART ports, UART1 is used for console and configured in > kernel command line, i.e. "console="; > > The UART1 probe failed and the memory allocated to sprd_port[1] was > released, but sprd_port[1] was not set to NULL; > > In UART2 probe, the same virtual address was allocated to sprd_port[2], > and UART2 probe process finally will go into sprd_console_setup() to > register UART1 as console since it is configured as preferred console > (filled to console_cmdline[]), but the console parameters (sprd_port[1]) > belong to UART2. > > So move the sprd_port[] assignment to where the port already initialized > can avoid the above issue. > > Fixes: b7396a38fb28 ("tty/serial: Add Spreadtrum sc9836-uart driver support") > Signed-off-by: Chunyan Zhang > --- > V2: > - Leave sprd_remove() to keep the unrelated code logic the same. > --- > drivers/tty/serial/sprd_serial.c | 25 +++++++++++++++++-------- > 1 file changed, 17 insertions(+), 8 deletions(-) > > diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c > index b58f51296ace..11de338a6122 100644 > --- a/drivers/tty/serial/sprd_serial.c > +++ b/drivers/tty/serial/sprd_serial.c > @@ -1106,7 +1106,7 @@ static bool sprd_uart_is_console(struct uart_port *uport) > static int sprd_clk_init(struct uart_port *uport) > { > struct clk *clk_uart, *clk_parent; > - struct sprd_uart_port *u = sprd_port[uport->line]; > + struct sprd_uart_port *u = container_of(uport, struct sprd_uart_port, port); > > clk_uart = devm_clk_get(uport->dev, "uart"); > if (IS_ERR(clk_uart)) { > @@ -1149,22 +1149,22 @@ static int sprd_probe(struct platform_device *pdev) > { > struct resource *res; > struct uart_port *up; > + struct sprd_uart_port *sport; > int irq; > int index; > int ret; > > index = of_alias_get_id(pdev->dev.of_node, "serial"); > - if (index < 0 || index >= ARRAY_SIZE(sprd_port)) { > + if (index < 0 || index >= UART_NR_MAX) { > dev_err(&pdev->dev, "got a wrong serial alias id %d\n", index); > return -EINVAL; > } > > - sprd_port[index] = devm_kzalloc(&pdev->dev, sizeof(*sprd_port[index]), > - GFP_KERNEL); > - if (!sprd_port[index]) > + sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL); > + if (!sport) > return -ENOMEM; > > - up = &sprd_port[index]->port; > + up = &sport->port; > up->dev = &pdev->dev; > up->line = index; > up->type = PORT_SPRD; > @@ -1195,7 +1195,7 @@ static int sprd_probe(struct platform_device *pdev) > * Allocate one dma buffer to prepare for receive transfer, in case > * memory allocation failure at runtime. > */ > - ret = sprd_rx_alloc_buf(sprd_port[index]); > + ret = sprd_rx_alloc_buf(sport); > if (ret) > return ret; > > @@ -1208,12 +1208,21 @@ static int sprd_probe(struct platform_device *pdev) > } > sprd_ports_num++; > > + sprd_port[index] = sport; > + > ret = uart_add_one_port(&sprd_uart_driver, up); > if (ret) > - sprd_remove(pdev); > + goto clean_port; > > platform_set_drvdata(pdev, up); > > + return 0; > + > +clean_port: > + sprd_port[index] = NULL; > + sprd_ports_num--; > + uart_unregister_driver(&sprd_uart_driver); I am not sure this is corect, in sprd_remove() it only calls uart_unregister_driver() when the 'sprd_ports_num' decreases to 0. > + sprd_remove(pdev); I don't think calling sprd_remove() is helpful here, since we have not saved 'up' into the driver data, which means the 'sprd_rx_free_buf(sup)' will not be called in sprd_remove(). So, to simplify the code, I think you can just add the sprd_rx_free_buf() into the 'clean_port' label: clean_port: sprd_rx_free_buf(sprd_port[index]); sprd_port[index] = NULL; sprd_ports_num--; if (!sprd_ports_num) uart_unregister_driver(&sprd_uart_driver); Then in patch 2, you can move the sprd_rx_free_buf() to the correct place to fix another potential leak issue.