Re: [PATCH v2] gpio: pca953x: Fix dereference of irq data in shutdown

[Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>]

On Thu, Feb 28, 2019 at 02:27:33PM +0000, Mark Walton wrote:
> If a PCA953x gpio was used as an interrupt and then released,
> the shutdown function was trying to extract the pca953x_chip
> pointer directly from the irq_data, but in reality was getting
> the gpio_chip structure.
> 
> The net effect was that the subsequent writes to the data
> structure corrupted data in the gpio_chip structure, which wasn't
> immediately obvious until attempting to use the GPIO again in the
> future, at which point the kernel panics.
> 
> This fix correctly extracts the pca953x_chip structure via the
> gpio_chip structure, as is correctly done in the other irq
> functions.
> 
> Fixes: 0a70fe00efea ("gpio: pca953x: Clear irq trigger type on irq shutdown")
> Signed-off-by: Mark Walton <mark.walton@xxxxxxxxxxxxx>
> ---
>  drivers/gpio/gpio-pca953x.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>