There are two legacy, deprecated functions - gpiod_to_chip() and
gpio_device_get_chip() - that still have users in tree. They return the
address of the SRCU-protected chip outside of the read-only critical
sections. They are inherently dangerous and the users should convert to
safer alternatives. Let's explicitly silence lockdep warnings by using
rcu_dereference_check(ptr, 1). While at it: reuse
gpio_device_get_chip() in gpiod_to_chip().
Fixes:
d83cee3d2bb1 ("gpio: protect the pointer to gpio_chip in gpio_device with SRCU")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/
202402122234.
d85cca9b-lkp@intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
{
if (!desc)
return NULL;
- return rcu_dereference(desc->gdev->chip);
+
+ return gpio_device_get_chip(desc->gdev);
}
EXPORT_SYMBOL_GPL(gpiod_to_chip);
*/
struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev)
{
- return rcu_dereference(gdev->chip);
+ return rcu_dereference_check(gdev->chip, 1);
}
EXPORT_SYMBOL_GPL(gpio_device_get_chip);