Commit 53ad4a94 authored Jan 26, 2026 by Yuhao Huang Committed by Bartosz Golaszewski Jan 27, 2026

gpio: virtuser: fix UAF in configfs release path

The gpio-virtuser configfs release path uses guard(mutex) to protect
the device structure. However, the device is freed before the guard
cleanup runs, causing mutex_unlock() to operate on freed memory.

Specifically, gpio_virtuser_device_config_group_release() destroys
the mutex and frees the device while still inside the guard(mutex)
scope. When the function returns, the guard cleanup invokes
mutex_unlock(&dev->lock), resulting in a slab use-after-free.

Limit the mutex lifetime by using a scoped_guard() only around the
activation check, so that the lock is released before mutex_destroy()
and kfree() are called.

Fixes: 91581c4b ("gpio: virtuser: new virtual testing driver for the GPIO API")
Signed-off-by: Yuhao Huang <nekowong743@gmail.com>
Link: https://lore.kernel.org/r/20260126040348.11167-1-yuhaohuang@YuhaodeMacBook-Pro.local

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

parent c0ae43d3

drivers/gpio/gpio-virtuser.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -1682,10 +1682,10 @@ static void gpio_virtuser_device_config_group_release(struct config_item *item)
		{
		struct gpio_virtuser_device *dev = to_gpio_virtuser_device(item);

		guard(mutex)(&dev->lock);

		scoped_guard(mutex, &dev->lock) {
		if (gpio_virtuser_device_is_live(dev))
		gpio_virtuser_device_deactivate(dev);
		}

		mutex_destroy(&dev->lock);
		ida_free(&gpio_virtuser_ida, dev->id);