gpiolib: cdev: add gpio_device locking wrapper around gpio_ioctl()
[ Upstream commit
1d656bd259edb89dc1d9938ec5c5389867088546 ]
While the GPIO cdev gpio_ioctl() call is in progress, the kernel can
call gpiochip_remove() which will set gdev->chip to NULL, after which
any subsequent access will cause a crash.
gpio_ioctl() was overlooked by the previous fix to protect syscalls
(
bdbbae241a04), so add protection for that.
Fixes:
bdbbae241a04 ("gpiolib: protect the GPIO device against being dropped while in use by user-space")
Fixes:
d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes:
3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Fixes:
aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>