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authorLinus Walleij <linus.walleij@linaro.org>2020-03-06 14:23:26 +0100
committerLinus Walleij <linus.walleij@linaro.org>2020-03-11 15:55:03 +0100
commit8959b304c7062889b1276092cc8590dc1ba98f65 (patch)
tree0149e54d643bf600e2df45205ba1980063c1702b /drivers/gpio/gpiolib.c
parentLinux 5.6-rc3 (diff)
downloadlinux-8959b304c7062889b1276092cc8590dc1ba98f65.tar.xz
linux-8959b304c7062889b1276092cc8590dc1ba98f65.zip
gpiolib: Fix irq_disable() semantics
The implementation if .irq_disable() which kicks in between the gpiolib and the driver is not properly mimicking the expected semantics of the irqchip core: the irqchip will call .irq_disable() if that exists, else it will call mask_irq() which first checks if .irq_mask() is defined before calling it. Since we are calling it unconditionally, we get this bug from drivers/pinctrl/qcom/pinctrl-ssbi-gpio.c, as it only defines .irq_mask_ack and not .irq_mask: Unable to handle kernel NULL pointer dereference at virtual address 00000000 pgd = (ptrval) (...) PC is at 0x0 LR is at gpiochip_irq_disable+0x20/0x30 Fix this by only calling .irq_mask() if it exists. Cc: Brian Masney <masneyb@onstation.org> Cc: Hans Verkuil <hans.verkuil@cisco.com> Cc: stable@vger.kernel.org Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Fixes: 461c1a7d4733 ("gpiolib: override irq_enable/disable") Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20200306132326.1329640-1-linus.walleij@linaro.org
Diffstat (limited to 'drivers/gpio/gpiolib.c')
-rw-r--r--drivers/gpio/gpiolib.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 4d0106ceeba7..00fb91feba70 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2306,9 +2306,16 @@ static void gpiochip_irq_disable(struct irq_data *d)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
+ /*
+ * Since we override .irq_disable() we need to mimic the
+ * behaviour of __irq_disable() in irq/chip.c.
+ * First call .irq_disable() if it exists, else mimic the
+ * behaviour of mask_irq() which calls .irq_mask() if
+ * it exists.
+ */
if (chip->irq.irq_disable)
chip->irq.irq_disable(d);
- else
+ else if (chip->irq.chip->irq_mask)
chip->irq.chip->irq_mask(d);
gpiochip_disable_irq(chip, d->hwirq);
}