From 225fce83cb72e1bffb712a33ce47c210c770f8ab Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 12 Jan 2015 17:12:25 +0100 Subject: [PATCH] gpio: fix gpio-chip list corruption Fix potential corruption of gpio-chip list due to failure to remove the chip from the list before returning in gpiochip_add error path. The chip could be long gone when the global list is next traversed, something which could lead to a null-pointer dereference. In the best case (chip not deallocated) we are just leaking the gpio range. Fixes: 14e85c0e69d5 ("gpio: remove gpio_descs global array") Signed-off-by: Johan Hovold Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 89c59f5f1924..ac5944b4e4d8 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -248,7 +248,8 @@ int gpiochip_add(struct gpio_chip *chip) base = gpiochip_find_base(chip->ngpio); if (base < 0) { status = base; - goto unlock; + spin_unlock_irqrestore(&gpio_lock, flags); + goto err_free_descs; } chip->base = base; } @@ -288,11 +289,8 @@ int gpiochip_add(struct gpio_chip *chip) acpi_gpiochip_add(chip); status = gpiochip_export(chip); - if (status) { - acpi_gpiochip_remove(chip); - of_gpiochip_remove(chip); - goto fail; - } + if (status) + goto err_remove_chip; pr_debug("%s: registered GPIOs %d to %d on device: %s\n", __func__, chip->base, chip->base + chip->ngpio - 1, @@ -300,9 +298,14 @@ int gpiochip_add(struct gpio_chip *chip) return 0; -unlock: +err_remove_chip: + acpi_gpiochip_remove(chip); + of_gpiochip_remove(chip); + spin_lock_irqsave(&gpio_lock, flags); + list_del(&chip->list); spin_unlock_irqrestore(&gpio_lock, flags); fail: +err_free_descs: kfree(descs); chip->desc = NULL; -- 2.39.2