Re: [PATCH] gpio: Fix lockdep warnings in gpiolib_{cdev,sysfs}_register()

[Bartosz Golaszewski]

On Sat, Feb 28, 2026 at 2:14 PM Tzung-Bi Shih <tzungbi@xxxxxxxxxx> wrote:
>
> A lockdep warning is reported in gpiolib-cdev driver:
>
>   WARNING: drivers/gpio/gpiolib-cdev.c:2735 at
>   gpiolib_cdev_register+0x114/0x140, CPU#1: swapper/0/1
>   Modules linked in:
>   CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted
>   7.0.0-rc1-next-20260227-00065-g6af4b9cfeded #12259 PREEMPT
>   Hardware name: Samsung Exynos (Flattened Device Tree)
>   Call trace:
>     unwind_backtrace from show_stack+0x10/0x14
>     show_stack from dump_stack_lvl+0x68/0x88
>     dump_stack_lvl from __warn+0x94/0x210
>     __warn from warn_slowpath_fmt+0x1b0/0x1bc
>     warn_slowpath_fmt from gpiolib_cdev_register+0x114/0x140
>     gpiolib_cdev_register from gpiochip_setup_dev+0x4c/0xd0
>     gpiochip_setup_dev from gpiochip_add_data_with_key+0x960/0xad4
>     gpiochip_add_data_with_key from devm_gpiochip_add_data_with_key+0x20/0x5c
>
> This is because the SRCU wasn't held in gpiolib_cdev_register() when the
> caller is from gpiochip_add_data_with_key() instead of
> gpiochip_setup_devs().  gpiochip_sysfs_register() shares the similar
> concern.
>
> Given that both gpiolib_cdev_register() and gpiochip_sysfs_register()
> are only called from gpiolib but no external users.  Remove the lockdep
> checks to fix the warnings.
>
> Reported-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> Closes: https://lore.kernel.org/all/506ce9b3-d492-4fce-9d02-330e411911e2@xxxxxxxxxxx/
> Fixes: cf674f1a0c98 ("gpio: Ensure struct gpio_chip for gpiochip_setup_dev()")
> Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx>
> ---

Marek: could you please leave your T-b if this fixes the issue?

Bart