Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 362432ae authored by Grant Likely's avatar Grant Likely
Browse files

gpiolib: Fix locking on gpio debugfs files 



The debugfs files really need to hold the gpiolib spinlock before
accessing the list. Otherwise chip addition/removal will cause an oops.

Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 6c0b4e6c

drivers/gpio/gpiolib.c

+9 −3
Original line number Diff line number Diff line
@@ -2053,29 +2053,35 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip) 


static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)

{

	unsigned long flags;

	struct gpio_chip *chip = NULL;

	loff_t index = *pos;



	/* REVISIT this isn't locked against gpio_chip removal ... */



	s->private = "";



	spin_lock_irqsave(&gpio_lock, flags);

	list_for_each_entry(chip, &gpio_chips, list)

		if (index-- == 0)

		if (index-- == 0) {

			spin_unlock_irqrestore(&gpio_lock, flags);

			return chip;

		}

	spin_unlock_irqrestore(&gpio_lock, flags);



	return NULL;

}



static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)

{

	unsigned long flags;

	struct gpio_chip *chip = v;

	void *ret = NULL;



	spin_lock_irqsave(&gpio_lock, flags);

	if (list_is_last(&chip->list, &gpio_chips))

		ret = NULL;

	else

		ret = list_entry(chip->list.next, struct gpio_chip, list);

	spin_unlock_irqrestore(&gpio_lock, flags);



	s->private = "\n";

	++*pos;