From: Tzung-Bi Shih <tzungbi@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Danilo Krummrich <dakr@kernel.org>,
Bartosz Golaszewski <brgl@bgdev.pl>,
Linus Walleij <linusw@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>, Shuah Khan <shuah@kernel.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Jason Gunthorpe <jgg@nvidia.com>, Johan Hovold <johan@kernel.org>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
chrome-platform@lists.linux.dev, tzungbi@kernel.org,
Dan Williams <dan.j.williams@intel.com>,
linux-gpio@vger.kernel.org
Subject: [PATCH v2 05/11] gpio: cdev: Don't check struct gpio_chip in gpio_chrdev_open()
Date: Tue, 3 Feb 2026 06:10:52 +0000 [thread overview]
Message-ID: <20260203061059.975605-6-tzungbi@kernel.org> (raw)
In-Reply-To: <20260203061059.975605-1-tzungbi@kernel.org>
It's harmless even if: chrdev_open() and cdev_device_del() run at the
same time, and gpio_chrdev_open() gets called after the underlying GPIO
chip has gone. The subsequent file operations check the availability
of struct gpio_chip anyway.
Don't check struct gpio_chip in gpio_chrdev_open().
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
v2:
- No changes.
v1: https://lore.kernel.org/all/20260116081036.352286-11-tzungbi@kernel.org
drivers/gpio/gpiolib-cdev.c | 6 ------
1 file changed, 6 deletions(-)
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index b89201578516..aaa5de814468 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -2689,12 +2689,6 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file)
struct gpio_chardev_data *cdev;
int ret = -ENOMEM;
- guard(srcu)(&gdev->srcu);
-
- /* Fail on open if the backing gpiochip is gone */
- if (!rcu_access_pointer(gdev->chip))
- return -ENODEV;
-
cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
if (!cdev)
return -ENOMEM;
--
2.53.0.rc2.204.g2597b5adb4-goog
next prev parent reply other threads:[~2026-02-03 6:12 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-03 6:10 [PATCH v2 00/11] gpio: Adopt revocable mechanism for UAF prevention Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 01/11] gpio: Access `gpio_bus_type` in gpiochip_setup_dev() Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 02/11] gpio: Remove redundant check for struct gpio_chip Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 03/11] gpio: sysfs: " Tzung-Bi Shih
2026-02-04 10:33 ` Bartosz Golaszewski
2026-02-05 8:51 ` Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 04/11] gpio: Ensure struct gpio_chip for gpiochip_setup_dev() Tzung-Bi Shih
2026-02-04 10:36 ` Bartosz Golaszewski
2026-02-05 8:51 ` Tzung-Bi Shih
2026-02-03 6:10 ` Tzung-Bi Shih [this message]
2026-02-03 6:10 ` [PATCH v2 06/11] selftests: gpio: Add gpio-cdev-uaf tests Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 07/11] gpio: Add revocable provider handle for struct gpio_chip Tzung-Bi Shih
2026-02-04 12:58 ` Bartosz Golaszewski
2026-02-05 8:52 ` Tzung-Bi Shih
2026-02-05 16:57 ` Bartosz Golaszewski
2026-02-06 9:13 ` Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 08/11] gpio: cdev: Leverage revocable for accessing " Tzung-Bi Shih
2026-02-03 9:51 ` Tzung-Bi Shih
2026-02-04 13:02 ` Bartosz Golaszewski
2026-02-03 6:10 ` [PATCH v2 09/11] gpio: Remove gpio_chip_guard by using revocable Tzung-Bi Shih
2026-02-04 13:05 ` Bartosz Golaszewski
2026-02-03 6:10 ` [PATCH v2 10/11] gpio: Leverage revocable for accessing struct gpio_chip Tzung-Bi Shih
2026-02-03 6:10 ` [PATCH v2 11/11] gpio: Remove unused `chip` and `srcu` in struct gpio_device Tzung-Bi Shih
2026-02-03 11:15 ` [PATCH v2 00/11] gpio: Adopt revocable mechanism for UAF prevention Bartosz Golaszewski
2026-02-03 16:53 ` Bartosz Golaszewski
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