From: Linus Walleij linus.walleij@linaro.org
commit 8959b304c7062889b1276092cc8590dc1ba98f65 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpio/gpiolib.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
--- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2323,9 +2323,16 @@ static void gpiochip_irq_disable(struct { 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); }