From d2d1819e29266cf26b2d649d9543c38afad57904 Mon Sep 17 00:00:00 2001
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Date: Wed, 24 Jan 2024 14:08:45 +0100
Subject: [PATCH] gpio: sysfs: extend the critical section for unregistering
 sysfs devices

BugLink: https://bugs.launchpad.net/bugs/2084005

[ Upstream commit 59cba4a0e6ca1058fbf88fec22530a4e2841802a ]

Checking the gdev->mockdev pointer for NULL must be part of the critical
section.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
---
 drivers/gpio/gpiolib-sysfs.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 6bf5332136e5..e6100260035c 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #include <linux/bitops.h>
+#include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/idr.h>
 #include <linux/init.h>
@@ -773,15 +774,15 @@ void gpiochip_sysfs_unregister(struct gpio_device *gdev)
 	struct gpio_desc *desc;
 	struct gpio_chip *chip = gdev->chip;
 
-	if (!gdev->mockdev)
-		return;
+	scoped_guard(mutex, &sysfs_lock) {
+		if (!gdev->mockdev)
+			return;
 
-	device_unregister(gdev->mockdev);
+		device_unregister(gdev->mockdev);
 
-	/* prevent further gpiod exports */
-	mutex_lock(&sysfs_lock);
-	gdev->mockdev = NULL;
-	mutex_unlock(&sysfs_lock);
+		/* prevent further gpiod exports */
+		gdev->mockdev = NULL;
+	}
 
 	/* unregister gpiod class devices owned by sysfs */
 	for_each_gpio_desc_with_flag(chip, desc, FLAG_SYSFS) {