[cocci] [PATCH] leds: trigger: oneshot: One function call less in pattern_init() after error detection

[cocci] [PATCH] leds: trigger: oneshot: One function call less in pattern_init() after error detection

[Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Tue, 26 Dec 2023 22:02:08 +0100

The kfree() function was called in one case by
the pattern_init() function during error handling
even if the passed variable contained a null pointer.
This issue was detected by using the Coccinelle software.

Thus use another label.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 drivers/leds/trigger/ledtrig-oneshot.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/trigger/ledtrig-oneshot.c b/drivers/leds/trigger/ledtrig-oneshot.c
index bee3bd452abf..31061ec0afe6 100644
--- a/drivers/leds/trigger/ledtrig-oneshot.c
+++ b/drivers/leds/trigger/ledtrig-oneshot.c
@@ -134,7 +134,7 @@ static void pattern_init(struct led_classdev *led_cdev)

 	pattern = led_get_default_pattern(led_cdev, &size);
 	if (!pattern)
-		goto out_default;
+		goto out_settings;

 	if (size != 2) {
 		dev_warn(led_cdev->dev,
@@ -151,6 +151,7 @@ static void pattern_init(struct led_classdev *led_cdev)

 out_default:
 	kfree(pattern);
+out_settings:
 	led_cdev->blink_delay_on = DEFAULT_DELAY;
 	led_cdev->blink_delay_off = DEFAULT_DELAY;
 }
--
2.43.0

Re: [cocci] leds: trigger: oneshot: One function call less in pattern_init() after error detection

[Markus Elfring]

>> The kfree() function was called in one case by
>> the pattern_init() function during error handling
>> even if the passed variable contained a null pointer.
>
> It's totally valid to call kfree() on a NULL pointer:
>
>   * If @object is NULL, no operation is performed.
>
> Why do we care all that much?

Would you dare to categorise such special function calls as redundant?

Should they be skipped in more cases?

See also:
https://wiki.sei.cmu.edu/confluence/display/c/MEM12-C.+Consider+using+a+goto+chain+when+leaving+a+function+on+error+when+using+and+releasing+resources


Regards,
Markus