Re: [PATCH] gpio/grgpio: fix deadlock in grgpio_irq_unmap()

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Mon, Aug 17, 2015 at 10:23 AM, Alexandre Courbot <acourbot@xxxxxxxxxx> wrote:

> As reported by Alexey Khoroshilov:
>
>     grgpio_irq_unmap() code looks quite suspicious regarding usage of
>     priv->bgc.lock spinlock.
>
>     It locks the spinlock in line 310:
>
>         spin_lock_irqsave(&priv->bgc.lock, flags);
>
>     and then it can call grgpio_set_imask() in line 317:
>
>         grgpio_set_imask(priv, i, 0);
>
>     But grgpio_set_imask() unconditionally locks the spinlock by itself.
>
> Fix this by moving the spinlock acquisition outside of
> grgpio_set_imask().
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Reported-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
> CC: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
> CC: Andreas Larsson <andreas@xxxxxxxxxxx>

Patch applied.

Yours,
Linus Walleij
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