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gpio: fix gpio-chip list corruption

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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: 14e85c0e69 ("gpio: remove gpio_descs global array")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Johan Hovold 2015-01-12 17:12:25 +01:00 committed by Linus Walleij
parent 5539b3c938
commit 225fce83cb
1 changed files with 10 additions and 7 deletions
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17
drivers/gpio/gpiolib.c
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@ -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;