linux-kernel - [PATCH 4.9 29/32] gpio: of: Fix of_gpiochip

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Message-Id: <20190502143322.727461789@linuxfoundation.org>
Date:   Thu,  2 May 2019 17:21:15 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Mukesh Ojha <mojha@...eaurora.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        "Sasha Levin (Microsoft)" <sashal@...nel.org>
Subject: [PATCH 4.9 29/32] gpio: of: Fix of_gpiochip_add() error path

[ Upstream commit f7299d441a4da8a5088e651ea55023525a793a13 ]

If the call to of_gpiochip_scan_gpios() in of_gpiochip_add() fails, no
error handling is performed.  This lead to the need of callers to call
of_gpiochip_remove() on failure, which causes "BAD of_node_put() on ..."
if the failure happened before the call to of_node_get().

Fix this by adding proper error handling.

Note that calling gpiochip_remove_pin_ranges() multiple times causes no
harm: subsequent calls are a no-op.

Fixes: dfbd379ba9b7431e ("gpio: of: Return error if gpio hog configuration failed")
Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
Reviewed-by: Mukesh Ojha <mojha@...eaurora.org>
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Sasha Levin (Microsoft) <sashal@...nel.org>
---
 drivers/gpio/gpiolib-of.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index aac84329c759..b863386be911 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -531,7 +531,13 @@ int of_gpiochip_add(struct gpio_chip *chip)
 
 	of_node_get(chip->of_node);
 
-	return of_gpiochip_scan_gpios(chip);
+	status = of_gpiochip_scan_gpios(chip);
+	if (status) {
+		of_node_put(chip->of_node);
+		gpiochip_remove_pin_ranges(chip);
+	}
+
+	return status;
 }
 
 void of_gpiochip_remove(struct gpio_chip *chip)
-- 
2.19.1