From: Bartosz Golaszewski Date: Fri, 16 Feb 2024 10:59:30 +0000 (+0100) Subject: gpio: cdev: fix a NULL-pointer dereference with DEBUG enabled X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=91510d5959ad9eac451685e3bfc8385b89c23908;p=linux.git 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 Closes: https://lore.kernel.org/lkml/179caa10-5f86-4707-8bb0-fe1b316326d6@samsung.com/ Signed-off-by: Bartosz Golaszewski Tested-by: Marek Szyprowski --- diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 85037fa4925e3..f384fa2787648 100644 --- 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);