FAILED: patch "[PATCH] tty/serial: digicolor: fix possible null-ptr-deref in" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 447ee1516f19f534a228dda237eddb202f23e163 Mon Sep 17 00:00:00 2001
From: Yang Yingliang <[email protected]>
Date: Thu, 5 May 2022 20:46:21 +0800
Subject: [PATCH] tty/serial: digicolor: fix possible null-ptr-deref in
digicolor_uart_probe()

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.

index 6d70fea76bb3..e37a917b9dbb 100644
@@ -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)