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gpiolib: initialize return value in gpiochip_set_multiple()

PATCH Applied Ruoyu Wang 3 participants 4 messages Jun 20 – Jun 22 1 message not in the archive GPIO

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Ruoyu Wang

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#0 lore raw

PATCH 1/1 gpiolib: initialize return value in gpiochip_set_multiple()

gpiochip_set_multiple() falls back to setting lines one by one when the chip does not provide set_multiple(). If the fallback path receives an empty mask, the loop is skipped and ret is returned without being initialized.

Initialize ret to 0 so an empty mask is treated as a successful no-op.

Fixes 9b407312755f ("gpiolib: rework the wrapper around gpio_chip::set_multiple()")
Signed-off-by Ruoyu Wang <[email protected]>
---
 drivers/gpio/gpiolib.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/gpio/gpiolib.c +1 -1
index 1e6dce430dca..cd2a619da456 100644
@@ -3778,7 +3778,7 @@ static int gpiochip_set_multiple(struct gpio_chip *gc,
 				 unsigned long *mask, unsigned long *bits)
 {
 	unsigned int i;
-	int ret;
+	int ret = 0;
 
 	lockdep_assert_held(&gc->gpiodev->srcu);
Acked-by on v1 1/1
#1 lore raw
Quoted 18 lines · Ruoyu Wang

gpiochip_set_multiple() falls back to setting lines one by one when the chip does not provide set_multiple(). If the fallback path receives an empty mask, the loop is skipped and ret is returned without being initialized.

Initialize ret to 0 so an empty mask is treated as a successful no-op.

Fixes 9b407312755f ("gpiolib: rework the wrapper around gpio_chip::set_multiple()")
Signed-off-by Ruoyu Wang <[email protected]>
---
 drivers/gpio/gpiolib.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/gpio/gpiolib.c +0 -0
index 1e6dce430dca..cd2a619da456 100644

drivers/gpio/gpiolib.c static int gpiochip_set_multiple(struct gpio_chip *gc, · line 3783

Quoted 7 lines
drivers/gpio/gpiolib.c +1 -1
@@ -3778,7 +3778,7 @@ static int gpiochip_set_multiple(struct gpio_chip *gc,
 				 unsigned long *mask, unsigned long *bits)
 {
 	unsigned int i;
-	int ret;
+	int ret = 0;
 
 	lockdep_assert_held(&gc->gpiodev->srcu);

While I think it's questionable to call gpiochip_set_multiple with an empty mask, returning a random value isn't the right reaction.

Acked-by Uwe Kleine-König <[email protected]>

Did you find that by manual code inspection, or using a tool?

Best regards
Uwe

Quoted 1 line

A message that is not in the archive (sent off-list or not yet received): CAK_7xqx_kJneD2=nDPYbefX_Ov0tf5sOwp5BLLLr7VzP9mtC_w@mail.gmail.com

#3 lore raw

Hello,

Quoted 3 lines · Ruoyu Wang

This was found by a local static analysis checker. The checker flagged the uninitialized return value candidate, and I then confirmed by manual inspection that the fallback loop can be skipped for an empty mask.

That might be worth to point out in the commit log.

Best regards
Uwe

Applied
#4 lore raw
In reply to Ruoyu Wang
Quoted 8 lines · Ruoyu Wang

gpiochip_set_multiple() falls back to setting lines one by one when the chip does not provide set_multiple(). If the fallback path receives an empty mask, the loop is skipped and ret is returned without being initialized.

Initialize ret to 0 so an empty mask is treated as a successful no-op.

[...]

Applied, thanks!

[1/1] gpiolib: initialize return value in gpiochip_set_multiple()

      https://git.kernel.org/brgl/c/99dfa46baba29513d1094c8f30bc86c6ef88543a

Best regards,

Signature · 1 line
Bartosz Golaszewski <[email protected]>