Commit 6bca1e95 authored by Eliav Farber's avatar Eliav Farber Committed by Greg Kroah-Hartman
Browse files

pps: clients: gpio: fix interrupt handling order in remove path 



The interrupt handler in pps_gpio_probe() is registered after calling
pps_register_source() using devm_request_irq(). However, in the
corresponding remove function, pps_unregister_source() is called before
the IRQ is freed, since devm-managed resources are released after the
remove function completes.

This creates a potential race condition where an interrupt may occur
after the PPS source is unregistered but before the handler is removed,
possibly leading to a kernel panic.

To prevent this, switch from devm-managed IRQ registration to manual
management by using request_irq() and calling free_irq() explicitly in
the remove path before unregistering the PPS source. This ensures the
interrupt handler is safely removed before deactivating the PPS source.

Signed-off-by: default avatarEliav Farber <farbere@amazon.com>
Link: https://lore.kernel.org/r/20250527053355.37185-1-farbere@amazon.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bfb4cf9f

drivers/pps/clients/pps-gpio.c

+3 −2
Original line number Diff line number Diff line
@@ -210,7 +210,7 @@ static int pps_gpio_probe(struct platform_device *pdev) 
	}



	/* register IRQ interrupt handler */

	ret = devm_request_irq(dev, data->irq, pps_gpio_irq_handler,

	ret = request_irq(data->irq, pps_gpio_irq_handler,

			  get_irqf_trigger_flags(data), data->info.name, data);

	if (ret) {

		pps_unregister_source(data->pps);
@@ -228,6 +228,7 @@ static void pps_gpio_remove(struct platform_device *pdev) 
{

	struct pps_gpio_device_data *data = platform_get_drvdata(pdev);



	free_irq(data->irq, data);

	pps_unregister_source(data->pps);

	timer_delete_sync(&data->echo_timer);

	/* reset echo pin in any case */