gpio: timberdale: fix off-by-one in IRQ type boundary check

[PATCH] gpio: timberdale: fix off-by-one in IRQ type boundary check

Posted by Junjie Cao 1 month, 1 week ago

timbgpio_irq_type() currently accepts offset == ngpio, violating
gpiolib's [0..ngpio-1] contract. This can lead to undefined behavior
when computing '1 << offset', and it is also inconsistent with users
that iterate with for_each_set_bit(..., ngpio).

Tighten the upper bound to reject offset == ngpio. No functional change
for in-range offsets.

Signed-off-by: Junjie Cao <junjie.cao@intel.com>
---
 drivers/gpio/gpio-timberdale.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-timberdale.c b/drivers/gpio/gpio-timberdale.c
index 679e27f00ff6..f488939dd00a 100644
--- a/drivers/gpio/gpio-timberdale.c
+++ b/drivers/gpio/gpio-timberdale.c
@@ -137,7 +137,7 @@ static int timbgpio_irq_type(struct irq_data *d, unsigned trigger)
 	u32 ver;
 	int ret = 0;
 
-	if (offset < 0 || offset > tgpio->gpio.ngpio)
+	if (offset < 0 || offset >= tgpio->gpio.ngpio)
 		return -EINVAL;
 
 	ver = ioread32(tgpio->membase + TGPIO_VER);
-- 
2.43.0

Re: [PATCH] gpio: timberdale: fix off-by-one in IRQ type boundary check

Posted by Bartosz Golaszewski 1 month, 1 week ago

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>


On Mon, 25 Aug 2025 17:08:50 +0800, Junjie Cao wrote:
> timbgpio_irq_type() currently accepts offset == ngpio, violating
> gpiolib's [0..ngpio-1] contract. This can lead to undefined behavior
> when computing '1 << offset', and it is also inconsistent with users
> that iterate with for_each_set_bit(..., ngpio).
> 
> Tighten the upper bound to reject offset == ngpio. No functional change
> for in-range offsets.
> 
> [...]

Applied, thanks!

[1/1] gpio: timberdale: fix off-by-one in IRQ type boundary check
      https://git.kernel.org/brgl/linux/c/810e154d90f44127239957b06ee51a55553a5815

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>