From 7fa25937542358bfa01ef5c5a1e9a00bd164c000 Mon Sep 17 00:00:00 2001 From: Alexandre Courbot Date: Mon, 17 Aug 2015 17:23:52 +0900 Subject: [PATCH] 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: Alexey Khoroshilov Signed-off-by: Alexandre Courbot Cc: Alexey Khoroshilov Cc: Andreas Larsson Signed-off-by: Linus Walleij --- drivers/gpio/gpio-grgpio.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/gpio/gpio-grgpio.c b/drivers/gpio/gpio-grgpio.c index 77053d61466e..801423fe8143 100644 --- a/drivers/gpio/gpio-grgpio.c +++ b/drivers/gpio/gpio-grgpio.c @@ -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 = {