Commit fa3b895d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'gpio-fixes-for-v5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux 

Pull gpio fix from Bartosz Golaszewski:

 - fix a race condition with consumers accessing the fields of GPIO IRQ
   chips before they're fully initialized

* tag 'gpio-fixes-for-v5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
  gpio: Restrict usage of GPIO chip irq members before initialization
parents e1f700eb 5467801f

drivers/gpio/gpiolib.c

+19 −0
Original line number Diff line number Diff line
@@ -1404,6 +1404,16 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset) 
{

	struct irq_domain *domain = gc->irq.domain;



#ifdef CONFIG_GPIOLIB_IRQCHIP

	/*

	 * Avoid race condition with other code, which tries to lookup

	 * an IRQ before the irqchip has been properly registered,

	 * i.e. while gpiochip is still being brought up.

	 */

	if (!gc->irq.initialized)

		return -EPROBE_DEFER;

#endif



	if (!gpiochip_irqchip_irq_valid(gc, offset))

		return -ENXIO;
@@ -1593,6 +1603,15 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc, 


	acpi_gpiochip_request_interrupts(gc);



	/*

	 * Using barrier() here to prevent compiler from reordering

	 * gc->irq.initialized before initialization of above

	 * GPIO chip irq members.

	 */

	barrier();



	gc->irq.initialized = true;



	return 0;

}

include/linux/gpio/driver.h

+9 −0
Original line number Diff line number Diff line
@@ -221,6 +221,15 @@ struct gpio_irq_chip { 
	 */

	bool per_parent_data;



	/**

	 * @initialized:

	 *

	 * Flag to track GPIO chip irq member's initialization.

	 * This flag will make sure GPIO chip irq members are not used

	 * before they are initialized.

	 */

	bool initialized;



	/**

	 * @init_hw: optional routine to initialize hardware before

	 * an IRQ chip will be added. This is quite useful when