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Commit 7fa25937 authored by Alexandre Courbot's avatar Alexandre Courbot Committed by Linus Walleij
Browse files

gpio/grgpio: fix deadlock in grgpio_irq_unmap() 



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: default avatarAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent ac49fbd1

drivers/gpio/gpio-grgpio.c

+10 −5
Original line number Diff line number Diff line
@@ -104,17 +104,12 @@ static void grgpio_set_imask(struct grgpio_priv *priv, unsigned int offset, 
{

	struct bgpio_chip *bgc = &priv->bgc;

	unsigned long mask = bgc->pin2mask(bgc, offset);

	unsigned long flags;



	spin_lock_irqsave(&bgc->lock, flags);



	if (val)

		priv->imask |= mask;

	else

		priv->imask &= ~mask;

	bgc->write_reg(priv->regs + GRGPIO_IMASK, priv->imask);



	spin_unlock_irqrestore(&bgc->lock, flags);

}



static int grgpio_to_irq(struct gpio_chip *gc, unsigned offset)
@@ -180,16 +175,26 @@ static void grgpio_irq_mask(struct irq_data *d) 
{

	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);

	int offset = d->hwirq;

	unsigned long flags;



	spin_lock_irqsave(&priv->bgc.lock, flags);



	grgpio_set_imask(priv, offset, 0);



	spin_unlock_irqrestore(&priv->bgc.lock, flags);

}



static void grgpio_irq_unmask(struct irq_data *d)

{

	struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);

	int offset = d->hwirq;

	unsigned long flags;



	spin_lock_irqsave(&priv->bgc.lock, flags);



	grgpio_set_imask(priv, offset, 1);



	spin_unlock_irqrestore(&priv->bgc.lock, flags);

}



static struct irq_chip grgpio_irq_chip = {