pt., 6 mar 2020 o 14:23 Linus Walleij linus.walleij@linaro.org napisał(a):

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 Fixes: 461c1a7d4733 ("gpiolib: override irq_enable/disable") Signed-off-by: Linus Walleij linus.walleij@linaro.org

---

drivers/gpio/gpiolib.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index bdbc1649eafa..d0bb962f42d5 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2169,9 +2169,16 @@ 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);
  

}

2.24.1

Reviewed-by: Bartosz Golaszewski bgolaszewski@baylibre.com