[tip:irq/urgent] irqchip/renesas-rza1: Prevent use-after-free in rza1_irqc_probe()

[tip-bot for Wen Yang]

Commit-ID:  7c8e90ddf02f139a90bc29c04302e9914818f0c8
Gitweb:     https://git.kernel.org/tip/7c8e90ddf02f139a90bc29c04302e9914818f0c8
Author:     Wen Yang <wen.yan...@zte.com.cn>
AuthorDate: Mon, 8 Jul 2019 14:19:04 +0800
Committer:  Thomas Gleixner <t...@linutronix.de>
CommitDate: Tue, 9 Jul 2019 14:53:50 +0200

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: a644ccb819bc ("irqchip: Add Renesas RZ/A1 Interrupt Controller driver")
Signed-off-by: Wen Yang <wen.yan...@zte.com.cn>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+rene...@glider.be>
Link: 
https://lkml.kernel.org/r/1562566745-7447-3-git-send-email-wen.yan...@zte.com.cn
---
 drivers/irqchip/irq-renesas-rza1.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/irqchip/irq-renesas-rza1.c 
b/drivers/irqchip/irq-renesas-rza1.c
index b1f19b210190..b0d46ac42b89 100644
--- a/drivers/irqchip/irq-renesas-rza1.c
+++ b/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)