Commit 7b99b5ab authored by Lad Prabhakar's avatar Lad Prabhakar Committed by Bartosz Golaszewski
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gpiolib: Fix potential NULL pointer dereference in gpiod_get_label() 



In `gpiod_get_label()`, it is possible that `srcu_dereference_check()` may
return a NULL pointer, leading to a scenario where `label->str` is accessed
without verifying if `label` itself is NULL.

This patch adds a proper NULL check for `label` before accessing
`label->str`. The check for `label->str != NULL` is removed because
`label->str` can never be NULL if `label` is not NULL.

This fixes the issue where the label name was being printed as `(efault)`
when dumping the sysfs GPIO file when `label == NULL`.

Fixes: 5a646e03 ("gpiolib: Return label, if set, for IRQ only line")
Fixes: a86d2769 ("gpiolib: fix the speed of descriptor label setting with SRCU")
Signed-off-by: default avatarLad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20241003131351.472015-1-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
parent 5a431e50

drivers/gpio/gpiolib.c

+2 −2
Original line number Diff line number Diff line
@@ -114,12 +114,12 @@ const char *gpiod_get_label(struct gpio_desc *desc) 
				srcu_read_lock_held(&desc->gdev->desc_srcu));



	if (test_bit(FLAG_USED_AS_IRQ, &flags))

		return label->str ?: "interrupt";

		return label ? label->str : "interrupt";



	if (!test_bit(FLAG_REQUESTED, &flags))

		return NULL;



	return label->str;

	return label ? label->str : NULL;

}



static void desc_free_label(struct rcu_head *rh)