From 7b99b5ab885993bff010ebcd93be5e511c56e28a Mon Sep 17 00:00:00 2001 From: Lad Prabhakar Date: Thu, 3 Oct 2024 14:13:51 +0100 Subject: 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: 5a646e03e956 ("gpiolib: Return label, if set, for IRQ only line") Fixes: a86d27693066 ("gpiolib: fix the speed of descriptor label setting with SRCU") Signed-off-by: Lad Prabhakar Link: https://lore.kernel.org/r/20241003131351.472015-1-prabhakar.mahadev-lad.rj@bp.renesas.com Signed-off-by: Bartosz Golaszewski --- drivers/gpio/gpiolib.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/gpio/gpiolib.c') diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index c6afbf434366..d5952ab7752c 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -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) -- cgit v1.2.3-70-g09d2