Re: [PATCH 2/2] gpiolib: Fix unaligned used of reference counters

From: Linus Walleij
Date: Wed Jun 08 2016 - 04:54:13 EST


On Fri, Jun 3, 2016 at 7:10 PM, Ricardo Ribalda Delgado
<ricardo.ribalda@xxxxxxxxx> wrote:

> gpiolib relies on the reference counters to clean up the gpio_device
> structure.
>
> Although the number of get/put is properly aligned on gpiolib.c
> itself, it does not take into consideration how the referece counters
> are affected by other external functions such as cdev_add and device_add.
>
> Because of this, after the last call to put_device, the reference counter
> has a value of +3, therefore never calling gpiodevice_release.
>
> Due to the fact that some of the device has already been cleaned on
> gpiochip_remove, the library will end up OOPsing the kernel (e.g. a call
> to of_gpiochip_find_and_xlate).
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx>

Again, thanks for fixing my stupid mistakes.

Applied and tagged for stable.

Yours,
Linus Walleij