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From:   Yang Yingliang <yangyingliang@huawei.com>
To:     <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-serial@vger.kernel.org>
CC:     <gregkh@linuxfoundation.org>, <jirislaby@kernel.org>,
        <baruch@tkos.co.il>
Subject: [PATCH] tty/serial: digicolor: fix possible null-ptr-deref in digicolor_uart_probe()
Date:   Thu, 5 May 2022 20:46:21 +0800
Message-ID: <20220505124621.1592697-1-yangyingliang@huawei.com>
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It will cause null-ptr-deref when using 'res', if platform_get_resource()
returns NULL, so move using 'res' after devm_ioremap_resource() that
will check it to avoid null-ptr-deref.
And use devm_platform_get_and_ioremap_resource() to simplify code.

Fixes: 5930cb3511df ("serial: driver for Conexant Digicolor USART")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 drivers/tty/serial/digicolor-usart.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/digicolor-usart.c b/drivers/tty/serial/digicolor-usart.c
index 6d70fea76bb3..e37a917b9dbb 100644
--- a/drivers/tty/serial/digicolor-usart.c
+++ b/drivers/tty/serial/digicolor-usart.c
@@ -471,11 +471,10 @@ static int digicolor_uart_probe(struct platform_device *pdev)
 	if (IS_ERR(uart_clk))
 		return PTR_ERR(uart_clk);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	dp->port.mapbase = res->start;
-	dp->port.membase = devm_ioremap_resource(&pdev->dev, res);
+	dp->port.membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 	if (IS_ERR(dp->port.membase))
 		return PTR_ERR(dp->port.membase);
+	dp->port.mapbase = res->start;
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
-- 
2.25.1