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 7E9A1C433F5 for ; Thu, 16 Dec 2021 14:15:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234758AbhLPOP3 (ORCPT ); Thu, 16 Dec 2021 09:15:29 -0500 Received: from smtp21.cstnet.cn ([159.226.251.21]:49698 "EHLO cstnet.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229612AbhLPOP2 (ORCPT ); Thu, 16 Dec 2021 09:15:28 -0500 Received: from localhost.localdomain (unknown [124.16.138.126]) by APP-01 (Coremail) with SMTP id qwCowAAnvqbgSbthnnSfAw--.52579S2; Thu, 16 Dec 2021 22:14:56 +0800 (CST) From: Jiasheng Jiang To: gregkh@linuxfoundation.org, jirislaby@kernel.org Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Jiasheng Jiang Subject: [PATCH v3] serial: pch_uart: potential dereference of null pointer Date: Thu, 16 Dec 2021 22:14:54 +0800 Message-Id: <20211216141454.423333-1-jiasheng@iscas.ac.cn> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: qwCowAAnvqbgSbthnnSfAw--.52579S2 X-Coremail-Antispam: 1UD129KBjvJXoWxAw4UuF4fXF4fWF48Jw1DZFb_yoW5GF4xpa 1jyrZ8A3yYq3Z3KF18Ar47Xr4avwn3CFy7KrW7KwnIyr9rtr1UCF15t3s0vrn5JrWxKryF vw4qyF45uF48taDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkv14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY02Avz4vE14v_Xryl 42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJV WUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAK I48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r 4UMIIF0xvE42xK8VAvwI8IcIk0rVWrZr1j6s0DMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF 0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JU6WlgUUUUU= X-Originating-IP: [124.16.138.126] X-CM-SenderInfo: pmld2xxhqjqxpvfd2hldfou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The return value of dma_alloc_coherent() needs to be checked. To avoid dereference of null pointer in case of the failure of alloc. Signed-off-by: Jiasheng Jiang --- Changelog: v2 -> v3 *Change 1. Remove dev_err. *Change 2. Change the return type of pch_request_dma to int. *Change 3. Return -ENOMEM when dma_alloc_coherent() failed and 0 the others. *Change 4. Check return value of dma_alloc_coherent(). --- drivers/tty/serial/pch_uart.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index f0351e6f0ef6..cfad5592010c 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -698,7 +698,7 @@ static bool filter(struct dma_chan *chan, void *slave) } } -static void pch_request_dma(struct uart_port *port) +static int pch_request_dma(struct uart_port *port) { dma_cap_mask_t mask; struct dma_chan *chan; @@ -723,7 +723,7 @@ static void pch_request_dma(struct uart_port *port) if (!chan) { dev_err(priv->port.dev, "%s:dma_request_channel FAILS(Tx)\n", __func__); - return; + return 0; } priv->chan_tx = chan; @@ -739,13 +739,20 @@ static void pch_request_dma(struct uart_port *port) __func__); dma_release_channel(priv->chan_tx); priv->chan_tx = NULL; - return; + return 0; } /* Get Consistent memory for DMA */ priv->rx_buf_virt = dma_alloc_coherent(port->dev, port->fifosize, &priv->rx_buf_dma, GFP_KERNEL); + if (!priv->rx_buf_virt) { + dma_release_channel(priv->chan_tx); + priv->chan_tx = NULL; + return -ENOMEM; + } + priv->chan_rx = chan; + return 0; } static void pch_dma_rx_complete(void *arg) @@ -1321,8 +1328,11 @@ static int pch_uart_startup(struct uart_port *port) if (ret < 0) return ret; - if (priv->use_dma) - pch_request_dma(port); + if (priv->use_dma) { + ret = pch_request_dma(port); + if (ret) + return ret; + } priv->start_rx = 1; pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT | @@ -1469,6 +1479,7 @@ static int pch_uart_verify_port(struct uart_port *port, struct serial_struct *serinfo) { struct eg20t_port *priv; + int ret; priv = container_of(port, struct eg20t_port, port); if (serinfo->flags & UPF_LOW_LATENCY) { @@ -1483,7 +1494,9 @@ static int pch_uart_verify_port(struct uart_port *port, return -EOPNOTSUPP; #endif if (!priv->use_dma) { - pch_request_dma(port); + ret = pch_request_dma(port); + if (ret) + return ret; if (priv->chan_rx) priv->use_dma = 1; } -- 2.25.1