gpio: cdev: fix a NULL-pointer dereference with DEBUG enabled

We are actually passing the gc pointer to chip_dbg() so we have to
srcu_dereference() it.

Fixes: 8574b5b47610 ("gpio: cdev: use correct pointer accessors with SRCU")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/lkml/179caa10-5f86-4707-8bb0-fe1b316326d6@samsung.com/
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 85037fa4925e3135c9b7563da866cf4f943e2c66..f384fa2787648e750802f909e810cc340c5efbf6 100644 (file)
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -2795,8 +2795,8 @@ int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
                return ret;
 
        guard(srcu)(&gdev->srcu);
-
-       if (!rcu_access_pointer(gdev->chip))
+       gc = srcu_dereference(gdev->chip, &gdev->srcu);
+       if (!gc)
                return -ENODEV;
 
        chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);