The GPIO controller is configured as non-sleeping but it uses generic pinctrl helpers which use a mutex for synchronization. This will cause lockdep splats when used together with shared GPIOs going through the GPIO shared proxy driver.
Fixes: 6e9be3abb78c ("pinctrl: Add driver support for Amlogic SoCs") Cc: stable@vger.kernel.org Reported-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Closes: https://lore.kernel.org/all/CAFBinCAc7CO8gfNQakCu3LfkYXuyTd2iRpMRm8EKXSL0mwO... Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@oss.qualcomm.com --- drivers/pinctrl/meson/pinctrl-amlogic-a4.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c index d9e3a8d5932a..ded7b218e2ec 100644 --- a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c +++ b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c @@ -893,7 +893,7 @@ static const struct gpio_chip aml_gpio_template = { .direction_input = aml_gpio_direction_input, .direction_output = aml_gpio_direction_output, .get_direction = aml_gpio_get_direction, - .can_sleep = false, + .can_sleep = true, };
static void init_bank_register_bit(struct aml_pinctrl *info,
On 1/6/26 09:52, Bartosz Golaszewski wrote:
The GPIO controller is configured as non-sleeping but it uses generic pinctrl helpers which use a mutex for synchronization. This will cause lockdep splats when used together with shared GPIOs going through the GPIO shared proxy driver.
Fixes: 6e9be3abb78c ("pinctrl: Add driver support for Amlogic SoCs") Cc: stable@vger.kernel.org Reported-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Closes: https://lore.kernel.org/all/CAFBinCAc7CO8gfNQakCu3LfkYXuyTd2iRpMRm8EKXSL0mwO... Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@oss.qualcomm.com
drivers/pinctrl/meson/pinctrl-amlogic-a4.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c index d9e3a8d5932a..ded7b218e2ec 100644 --- a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c +++ b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c @@ -893,7 +893,7 @@ static const struct gpio_chip aml_gpio_template = { .direction_input = aml_gpio_direction_input, .direction_output = aml_gpio_direction_output, .get_direction = aml_gpio_get_direction,
- .can_sleep = false,
- .can_sleep = true, };
static void init_bank_register_bit(struct aml_pinctrl *info,
Reviewed-by: Neil Armstrong neil.armstrong@linaro.org
Thanks, Neil
Hi Bartosz, Could you explain the reproduction method for this problem ?
On 2026/1/6 16:55, Neil Armstrong wrote:
The GPIO controller is configured as non-sleeping but it uses generic pinctrl helpers which use a mutex for synchronization. This will cause lockdep splats when used together with shared GPIOs going through the GPIO shared proxy driver.
Fixes: 6e9be3abb78c ("pinctrl: Add driver support for Amlogic SoCs") Cc: stable@vger.kernel.org Reported-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Closes: https://lore.kernel.org/all/CAFBinCAc7CO8gfNQakCu3LfkYXuyTd2iRpMRm8EKXSL0mwO... Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@oss.qualcomm.com
drivers/pinctrl/meson/pinctrl-amlogic-a4.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c index d9e3a8d5932a..ded7b218e2ec 100644 --- a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c +++ b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c @@ -893,7 +893,7 @@ static const struct gpio_chip aml_gpio_template = { .direction_input = aml_gpio_direction_input, .direction_output = aml_gpio_direction_output, .get_direction = aml_gpio_get_direction, - .can_sleep = false, + .can_sleep = true, };
static void init_bank_register_bit(struct aml_pinctrl *info,
On Tue, Jan 6, 2026 at 10:32 AM Xianwei Zhao xianwei.zhao@amlogic.com wrote:
Hi Bartosz, Could you explain the reproduction method for this problem ?
Please don't top-post on the mailing list.
If you have a pin shared by multiple devices in device-tree, it will now go through a dedicated gpio-shared-proxy driver. It will use a locking mechanism depending on the can_sleep flag of the GPIO controller device - spinlock or mutex. If the flag is wrong - like is the case here - it may happen that we take a spinlock and then descend into pinctrl where a mutex is taken resulting in a lockdep splat.
Bart
On Tue, Jan 6, 2026 at 9:53 AM Bartosz Golaszewski bartosz.golaszewski@oss.qualcomm.com wrote:
The GPIO controller is configured as non-sleeping but it uses generic pinctrl helpers which use a mutex for synchronization. This will cause lockdep splats when used together with shared GPIOs going through the GPIO shared proxy driver.
Fixes: 6e9be3abb78c ("pinctrl: Add driver support for Amlogic SoCs") Cc: stable@vger.kernel.org Reported-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Closes: https://lore.kernel.org/all/CAFBinCAc7CO8gfNQakCu3LfkYXuyTd2iRpMRm8EKXSL0mwO... Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@oss.qualcomm.com
Reviewed-by: Martin Blumenstingl martin.blumenstingl@googlemail.com
On Tue, Jan 6, 2026 at 9:53 AM Bartosz Golaszewski bartosz.golaszewski@oss.qualcomm.com wrote:
The GPIO controller is configured as non-sleeping but it uses generic pinctrl helpers which use a mutex for synchronization. This will cause lockdep splats when used together with shared GPIOs going through the GPIO shared proxy driver.
Fixes: 6e9be3abb78c ("pinctrl: Add driver support for Amlogic SoCs") Cc: stable@vger.kernel.org Reported-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Closes: https://lore.kernel.org/all/CAFBinCAc7CO8gfNQakCu3LfkYXuyTd2iRpMRm8EKXSL0mwO... Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@oss.qualcomm.com
Patch applied for fixes!
Yours, Linus Walleij
On Tue, Jan 6, 2026 at 9:53 AM Bartosz Golaszewski bartosz.golaszewski@oss.qualcomm.com wrote:
The GPIO controller is configured as non-sleeping but it uses generic pinctrl helpers which use a mutex for synchronization. This will cause lockdep splats when used together with shared GPIOs going through the GPIO shared proxy driver.
BTW it is a very *welcome* side-effect of the new shared GPIO rework that it just happens to find these old bugs, I'm very pleased with this :)
Yours, Linus Walleij
On Fri, Jan 9, 2026 at 10:35 AM Linus Walleij linusw@kernel.org wrote:
On Tue, Jan 6, 2026 at 9:53 AM Bartosz Golaszewski bartosz.golaszewski@oss.qualcomm.com wrote:
The GPIO controller is configured as non-sleeping but it uses generic pinctrl helpers which use a mutex for synchronization. This will cause lockdep splats when used together with shared GPIOs going through the GPIO shared proxy driver.
BTW it is a very *welcome* side-effect of the new shared GPIO rework that it just happens to find these old bugs, I'm very pleased with this :)
Actually, I was surprised I was getting so many bug reports and then it turned out, there was a bug that caused a lot of false-positives to turn up when scanning the devicetree for shared pins. I just queued a fix for that so it should slow down now.
Bart
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Xianwei Zhao