[PATCH] gpio: initialize descriptor SRCU structure before adding OF-based chips

From: Bartosz Golaszewski
Date: Mon Feb 12 2024 - 16:39:40 EST


From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

In certain situations we may end up taking the GPIO descriptor SRCU read
lock in of_gpiochip_add() before the SRCU struct is initialized. Move
the initialization before the call to of_gpiochip_add().

Fixes: be711caa87c5 ("gpio: add SRCU infrastructure to struct gpio_desc")
Fixes: 1f2bcb8c8ccd ("gpio: protect the descriptor label with SRCU")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-lkp/202402122228.e607a080-lkp@xxxxxxxxx
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
---
drivers/gpio/gpiolib.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 82811d9a4477..f5434e559382 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -991,10 +991,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
if (ret)
goto err_cleanup_gdev_srcu;

- ret = of_gpiochip_add(gc);
- if (ret)
- goto err_free_gpiochip_mask;
-
for (i = 0; i < gc->ngpio; i++) {
struct gpio_desc *desc = &gdev->descs[i];

@@ -1002,7 +998,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
if (ret) {
for (j = 0; j < i; j++)
cleanup_srcu_struct(&gdev->descs[j].srcu);
- goto err_remove_of_chip;
+ goto err_free_gpiochip_mask;
}

if (gc->get_direction && gpiochip_line_is_valid(gc, i)) {
@@ -1014,10 +1010,14 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
}
}

- ret = gpiochip_add_pin_ranges(gc);
+ ret = of_gpiochip_add(gc);
if (ret)
goto err_cleanup_desc_srcu;

+ ret = gpiochip_add_pin_ranges(gc);
+ if (ret)
+ goto err_remove_of_chip;
+
acpi_gpiochip_add(gc);

machine_gpiochip_add(gc);
@@ -1055,12 +1055,12 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
gpiochip_irqchip_free_valid_mask(gc);
err_remove_acpi_chip:
acpi_gpiochip_remove(gc);
-err_cleanup_desc_srcu:
- for (i = 0; i < gdev->ngpio; i++)
- cleanup_srcu_struct(&gdev->descs[i].srcu);
err_remove_of_chip:
gpiochip_free_hogs(gc);
of_gpiochip_remove(gc);
+err_cleanup_desc_srcu:
+ for (i = 0; i < gdev->ngpio; i++)
+ cleanup_srcu_struct(&gdev->descs[i].srcu);
err_free_gpiochip_mask:
gpiochip_remove_pin_ranges(gc);
gpiochip_free_valid_mask(gc);
--
2.40.1