irqchip/renesas-rza1: Prevent use-after-free in rza1_irqc_probe()

The gic_node is still being used in the rza1_irqc_parse_map() call
after the of_node_put() call, which may result in use-after-free.

Fixes: a644ccb8 ("irqchip: Add Renesas RZ/A1 Interrupt Controller driver")
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lkml.kernel.org/r/1562566745-7447-3-git-send-email-wen.yang99@zte.com.cn

drivers/irqchip/irq-renesas-rza1.c

@@ -208,20 +208,19 @@ static int rza1_irqc_probe(struct platform_device *pdev)
 		return PTR_ERR(priv->base);
 
 	gic_node = of_irq_find_parent(np);
-	if (gic_node) {
+	if (gic_node)
 		parent = irq_find_host(gic_node);
-		of_node_put(gic_node);
-	}
 
 	if (!parent) {
 		dev_err(dev, "cannot find parent domain\n");
-		return -ENODEV;
+		ret = -ENODEV;
+		goto out_put_node;
 	}
 
 	ret = rza1_irqc_parse_map(priv, gic_node);
 	if (ret) {
 		dev_err(dev, "cannot parse %s: %d\n", "interrupt-map", ret);
-		return ret;
+		goto out_put_node;
 	}
 
 	priv->chip.name = "rza1-irqc",
@@ -237,10 +236,12 @@ static int rza1_irqc_probe(struct platform_device *pdev)
 						    priv);
 	if (!priv->irq_domain) {
 		dev_err(dev, "cannot initialize irq domain\n");
-		return -ENOMEM;
+		ret = -ENOMEM;
 	}
 
-	return 0;
+out_put_node:
+	of_node_put(gic_node);
+	return ret;
 }
 
 static int rza1_irqc_remove(struct platform_device *pdev)