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gpio/grgpio: fix deadlock in grgpio_irq_unmap()

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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@ispras.ru>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Alexandre Courbot 2015-08-17 17:23:52 +09:00 committed by Linus Walleij
parent ac49fbd1f9
commit 7fa2593754
1 changed files with 10 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/gpio/gpio-grgpio.c
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@ -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 = {